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UBC Theses and Dissertations

Gallium arsenide integrated circuit modeling, layout and fabrication 1987

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GALLIUM ARSENIDE INTEGRATED CIRCUIT MODELING, LAYOUT AND FABRICATION by WILLIAM C. RUTHERFORD A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF APPLIED SCIENCE i n THE FACULTY OF GRADUATE STUDIES DEPARTMENT OF ELECTRICAL ENGINEERING We a c c e p t t h i s t h e s i s as c o n f o r m i n g t o t h e r e q u i r e d s t a n d a r d THE UNIVERSITY OF BRITISH COLUMBIA MAY 1987 © WILLIAM C. RUTHERFORD, 1987 In presenting this thesis in partial fulfilment of the requirements for an advanced degree at the University of British Columbia, I agree that the Library shall make it freely available for reference and study. I further agree that permission for extensive copying of this thesis for scholarly purposes may be granted by the head of my department or by his or her representatives. It is understood that copying or publication of this thesis for financial gain shall not be allowed without my written permission. Department The University of British Columbia 1956 Main Mall Vancouver, Canada V6T 1Y3 Date J u ^ e / f l , 1971 DE-6(3/81) ABSTRACT The object of the work described in this thesis was to develop GaAs integrated circuit modeling techniques based on a modified version of SPICE 2, then layout, fabricate, model and test ion implanted GaAs MESFET integrated sample and hold circuits. A large signal GaAs MESFET model was used in SPICE to evaluate the relative performance of inverted common drain logic (ICDL) digital integrated circuits compared to other circuit configurations. The integrated sample and hold subsequently referred to as an integrated sampling amplifier block(ISAB), uses a MESFET switch with either one or two guard gates to suppress strobe feedthrough. Performance guidelines suggested by the project sponsor indicate an optimal switch sampling pulse width capability of 25 ps with 5 ps rise and f a l l time. Guard gates are included in the switch layout to evaluate pulse feedthrough minimization. The project sponsor suggested -20 dB pulse feedthrough isolation and minimum sampling switch off isolation of -20 dB at 10 GHz as project guidelines. Simulations indicate that a 0.5 urn gate length process approaches the suggested performance guidelines. A mask layout was designed and modeled including both selective implant and refractory self aligned gate processes. The refractory self aligned gate process plasma etched t-gate i i structure produces a sub 0.5 Mm gate length. Ac knowledgement Our work on the integrated sampling amplifier block was supported by the Defense Research Establishment Ottawa. I thank my supervisor, Dr. L . Young, for his guidance and for suggesting many of the ideas in this work. Mr. Salam Dindo is to be thanked for his advice concerning layout topology and process optimization. Mr. David Michelson is to be thanked for his discussions of microwave circuit considerations. Mr. Bruce Beggs is to be thanked for his collaboration in developing fine line lithography techniques. Mr. Peter Townsley is to be thanked for his effort in getting the f i r s t two runs of selective implant devices working. Mrs. Mary Mager is to be thanked for instructing Bruce Beggs and myself on the intricacies of SEM photography. Mr. Martin Lord is to be thanked for his effort to get discrete MESFET test fixtures built by Microtel Pacific Research Ltd. Mr. Hiroshi Kato is to be thanked for his work on the RSAG process. i v Table of Contents ABSTRACT . i i Acknowledgement iv List of Tables v i i i List of Figures ix Symbol Definitions x i i List of Acronyms xvi 1. Introduction 1 1.1 Integrated Sampling Amplifier Overview 1 2. Process Definition, Parameter Extraction and Mask Layout 14 2.0.1 Process Parameters 14 2.1 Process Definition 15 2.1.1 Process Listing 16 3. Schottky Diode Parameter Extraction and Layout 30 4. MESFET Parameter Extraction and Layout 34 4.1 Alignment Limitations 34 4.1.1 Interlayer Alignment Marks 35 4.2 RSAG and Selective Implant Process Parameter Differences 37 4.2.1 Source and Drain Resistance 37 4.2.2 Gate Phase Shift 39 4.3 MESFET Capacitance 41 4.4 MESFET 1 Mm Slice Parameters 42 5. Switch Considerations and Layout 51 5.1 The Sampling Cycle 54 5.2 Guard and Sampling Gate Biasing Considerations 56 5.3 Hold Capacitance Considerations 56 v 6. Amplifier Layout 59 7. ISAB Design and Layouts 66 7.1 Configurations 66 7.2 I SAB Simulation Results 68 8. Process Monitors and Measured Results 87 8.1 Isolation Monitors 87 8.2 TLMs 87 8.3 Power MESFET 88 8.4 TiW Sheet Resistance 88 8.5 Three Amplifier Oscillator 89 8.6 Peaking Inductor ...89 8.7 Selective Implant Fabrication Run Results 91 8.7.1 Isolation 91 8.7.2 Doping and Mobility Profiles 92 8.7.3 SI MESFET Characteristics 94 9. Conclusion 96 REFERENCES 97 10. Appendix A -ICDL Simulations 102 10.1 Digital Integrated Circuit Simulation Overview 102 10.2 ICDL Basic Circuits 105 10.3 Buffer Circuit 107 10.4 Inverter 110 10.5 Buffered Inverter 115 10.6 OR Gate 115 10.7 AND Gate 115 10.8 Results and their SPICE Simulation 116 REFERENCES FOR APPENDIX A ....119 vi 11. A p p e n d i x B - L a y o u t s 121 12. A p p e n d i x C -GASFET S u b r o u t i n e 123 13. A p p e n d i x D - S i m u l a t i o n S o u r c e L i s t i n g s 129 v i i List of Tables Table Description Page 1.1 Overall mask pattern die locations.... 12 2.1 Process Parameters 14 2.2 Process Plates 15 4.1 Thin film resistivity 40 5.1 MESFET parameters for sampling switches 58 v i i i List of Figures Figure Description Page 1.1 Integrated Sampling Amplifier Block configuration 3 1.2 Triple Gate Switch Cross Sections 5 1.3 Overall layout pattern 7 2.1 Nonbevelled PR edge profile, no chlorobenzene soak 17 2.2 Bevelled profile with chlorobenzene... 19 2.3 N" implant profile 20 2.4 SEM photograph of alignment 21 2.5 SEM photograph of 1/Ltm gate before l i f t o f f 22 2.6 SEM photograph of Ijim gate after l i f t o f f 23 2.7 Cross Section of MIM 25 2.8 MESFET Gate Cross Sections.. 28 3.1 Schottky diode cross sections 30 4.1 Alignment marks 36 4.2 Cross section of MESFETs 38 4.3 MESFET circuit model 42 4.4 a) 7r-Gate Layout 43 4.4 b) 7r-Gate Magnified 44 4.5 RSAG 0.5Mm characteristics 45 4.6 RSAG lAim characteristics 46 ix 4.7 SI c h a r a c t e r i s t i c s 47 5.1 a) T r i p l e Gate Switch Layout 51 5.1 b) Ma g n i f i e d T r i p l e Gate Switch 52 5.2 T r i p l e Gate Switch S l i c e E q u i v a l e n t C i r c u i t 53 5.3 T r i p l e Gate Switch D i s t r i b u t e d Model..53 5.4 S i n g l e Gate D i s t r i b u t e d S i m u l a t i o n . . . . 55 6.1 A m p l i f i e r E q u i v a l e n t C i r c u i t 59 6.2 A m p l i f i e r Layout 60 6.3 A m p l i f i e r Open Loop DC C h a r a c t e r i s t i c . 6 1 6.4 AORT3_9012 Open Loop T r a n s i e n t 61 6.5 90mn RSAG1_2 A m p l i f i e r DC Character i st i c s 62 6.6 90/im RSAG1_2 A m p l i f i e r Step Response..62 6.7 90MITI RSAG2_2 A m p l i f i e r DC C h a r a c t e r i s t i c s 63 6.8 90mri RSAG2_2 A m p l i f i e r Step Response..63 6.9 90/im SI1_2 A m p l i f i e r DC C h a r a c t e r i s t i c s 64 6.10 90MITI S11_2 A m p l i f i e r Step Response.... 64 7.1 SI and RSAG I SAB layout ...66 7.2 MIM ISAB layout 67 7.3 RSAG1_2 S i n g l e Gate ISAB T r a c k i n g 69 7.4 RSAG1_2 Dual Gate ISAB T r a c k i n g 69 7.5 RSAG1_2 T r i p l e Gate ISAB T r a c k i n g 70 7.6 RSAG1_2 S i n g l e Gate Time Constant 70 7.7 RSAG1_2 Dual Gate Time Constant 71 x 7.8 RSAG1_2 Triple Gate Time Constant 71 7.9 Pad Pulse Distortion 72 7.10 Single Gate Feedthrough 73 7.11 Dual Gate Feedthrough 73 7.12 Triple Gate Feedthrough ..74 7.13 Guard Gate Source and Drain Voltages..76 7.14 Guard Gate Current 77 7.15 RI16R912T3 150ps Tracking, 0.6 V Bias.79 7.16 RI16R912T3 150ps Tracking, 0.4 V Bias.80 7.17 RI16R912T3 75ps Tracking 81 7.18 RI16R912T3 25ps Tracking 82 7.19 RI36R912T3 300ps Tracking 83 7.20 RI26R912T3 50ps Tracking 84 8.1 Power MESFET Gate Strip Layout 88 8.2 TiW Stepped Resistor Layout 89 8.3 Test Oscillator OFRT3_9013 90 8.4 Amplifier Peaking Inductor 90 8.5 Isolation monitor chip 8. 91 8.6 Isolation monitor chip 5 ...92 8.7 SI doping profile 93 8.8 SI mobility profile..... 93 8.9 S F _ 2 3 6 _ 1 _ 4 *~gate I-V characteristics.94 xi Symbol Definitions Symbol Units Description 5 I Mm mask intra layer skew *L Mm mask inter layer skew « A Mm mask alignment skew 5 LA Mm lateral alloy movement e F/cm free space permittivity GaAs F/cm permittivity of GaAs, taken as 12. 9e cm2/V-s Hall mobility cmJ/V-s electron low fi e l d d r i f t mobility cm2/V-s electron d r i f t mobility P 0/cm specific resi s t i v i t y Pen fi/Mm2 contact specific resistance, C1 = N + GaAs to AuGe, C2 = AuGe to TiW. ARp standard deviation of the implant r ps channel transit time = L/v^r VS cm/s saturated electron d r i f t velocity ="nEs *Bn V Schottky barrier height on n-GaAs ©G rad/Mm gate phase shift fi A/V2 MESFET model current gain factor X v- • channel length modulation parameter a hyperbolic tangent function parameter E s V/cm velocity saturation f i e l d =vs/vn L Mm channel length xi i t Mm a p p a r e n t c h a n n e l t h i c k n e s s A Mm e f f e c t i v e u n i f o r m p r o f i l e c h a n n e l t h i c k n e s s LQ Mm m e t a l l u r g i c a l g a t e l e n g t h L g a p Mm e f f e c t i v e M E S F E T s o u r c e o r d r a i n t o g a t e gap or d i o d e S c h o t t k y m e t a l t o ohmic gap. Z Mm g a t e w i d t h d i m e n s i o n CGD fF/Mm g a t e t o d r a i n c a p a c i t a n c e CQg fF/Mm g a t e t o s o u r c e c a p a c i t a n c e C D S fF/Mm d r a i n t o s o u r c e c a p a c i t a n c e Cgc fF/Mm s p a c e c h a r g e c a p a c i t a n c e R p S fl/Mm S c h o t t k y d i o d e p a r a s i t i c s e r i e s r e s i s t a n c e R G ft g a t e s e r i e s r e s i s t a n c e Rg fl s o u r c e s e r i e s r e s i s t a n c e R D fl d r a i n s e r i e s r e s i s t a n c e R s i ft/n L E C GaAs s e m i - i n s u l a t i n g s h e e t r e s i s t i v i t y R g H ft d r a i n t o s o u r c e s h u n t r e s i s t a n c e g m mA/V 9 I D S / 3 V G S I D g mk/nm d r a i n t o s o u r c e c u r r e n t ^ S S mA/Mm s a t u r a t e d d r a i n t o s o u r c e c u r r e n t a t s t a t e d V Q S and V D S x i i i V-,- V internal gate to source voltage V Gg V external gate to source voltage V^g V internal drain to source voltage V Dg V external drain to source voltage V^g V substrate bias voltage f T Hz cutoff frequency = 1/(27rr) V (positive) b u i l t - i n voltage at the gate V p V pinchoff voltage =q/e G a A s/^N(x)xdx V T V threshold voltage V T=V p+V b i WQ Mm zero gate bias depletion width Wi Mm the doping p r o f i l e depth at a doping le v e l of 10' 6 n diode i d e a l i t y factor N(x) ions/cm 3 activated ion implanted doping p r o f i l e N a ions/cm 3 e f f e c t i v e p-doping substrate concentrat ion N D ions/cm 3 e f f e c t i v e uniform p r o f i l e channel doping density Nmax ions/cm 3 peak value of doping p r o f i l e q C electron charge n e/cm3 free electron concentration n^ e/cm3 i n t r i n s i c free electron concentration NQ s/cm3 e f f e c t i v e density of states in conduction band xiv N T s/cm3 total concentration of traps Q1 ions/cm2 total N" dose Q_2 ions/cm2 total N+ dose Qa ions/cm available dose =/oN(x)dx keV N" implant energy $ 2 keV N + implant energy RpQ cm projected range of the implantation Rp cm effective projected range Rp0-ARp xv List of Acronyms Acronym Meaning BFL buffered FET logic CAD computer aided design EBL electron beam lithography ID interdigitated MBE molecular beam epitaxy MESFET metal semiconductor fi e l d effect transistor MIM metal insulator metal PR positive photoresist RD refractory diode RIE reactive ion etch RSAG refractory self aligned gate ISAB integrated sampling amplifier block SD selective implant diode SEM scanning electron microscope SI selective implant SPICE simulation program with integrated circuit emphasis TD two implant diode, SD on N+ xvi 1. INTRODUCTION The purpose of this work was to investigate the design, simulation and fabrication of GaAs devices and in particular of a GaAs sample and hold device. The work was sponsored by the Defense Research Establishment Ottawa. 1.1 INTEGRATED SAMPLING AMPLIFIER OVERVIEW One of the target applications for integrated GaAs sample and holds is a microwave acquisition system or digital radio frequency memory(DRFM)[1.1]. This involves sampling a microwave frequency signal on an input delay line at regular distributed points. Ideally the entire unit would be constructed on a single chip, complete with microstrip delay line, pulse generator, controller circuits, and analog to digital conversion. The primary purpose of the simulation, layout and fabrication is to investigate and optimize, as far as possible within the confines of the available process parameters, the performance of the integrated sampling amplifier (ISAB). The most important aspects of the ISAB are a low input time constant, ideally less than 25ps, combined with minimal strobe "blow-by". In previous published work Saul[1.2] demonstrated a MESFET switch ring approach with greater than 40dB of "OFF" isolation and an acquisition time of 2ns suggesting operation up to 250MHz. Sample pulse "blow-by" or feedthrough was minimized by careful chip and circuit layout 1 2 t o m i n i m i z e c a p a c i t i v e c o u p l i n g . Sample s t r o b e f e e d t h r o u g h ranged from a worst c a s e of about 80mV t o an ave r a g e of about 20 t o 30 mV on a 2.5V s i g n a l c o r r e s p o n d i n g t o about 40dB of s t r o b e i s o l a t i o n from t h e sampled s i g n a l . A 1/zm SI t r i p l e g a t e MESFET s w i t c h ISAB w i t h a 65ps i n p u t t i m e c o n s t a n t was b u i l t and t e s t e d t o 500 Megasamples per second, u s i n g a 36MHz sine-wave i n p u t by G.S. B a r t a and A.G. R o d e [ 1 . 3 ] . I s o l a t i o n i n t h e "OFF" s t a t e was about 40dB w i t h a MHz band i n p u t . Sample s t r o b e blow-by was -35mV on a 300 mV s i g n a l , c o r r e s p o n d i n g t o 18.6dB of s t r o b e i s o l a t i o n . The t e s t equipment was c o n s i d e r e d i n a d e q u a t e f o r t h e f u l l c a p a b i l i t y of the d e v i c e . I f the MIM c a p a c i t o r was o m i t t e d an i n p u t time c o n s t a n t of about 33ps would r e s u l t , c l o s e t o th e d e s i r e d s p e c i f i c a t i o n . However absence of t h e MIM c a p a c i t o r would l i k e l y r e s u l t i n a r e d u c t i o n of s t r o b e i s o l a t i o n below the a l r e a d y m a r g i n a l s p e c i f i c a t i o n . Work a t U.B.C. by D u r t l e r a t t e m p t e d t o e x t e n d t h e r e s u l t s of B a r t a and Rode u s i n g a s i n g l e and d u a l g a t e s w i t c h c o n f i g u r a t i o n f 1 . 4 ] . The ISAB c o n f i g u r a t i o n , shown i n f i g u r e 1.1, c o n s i s t s of e i t h e r a s i n g l e , d u a l o r t r i p l e gate s a m p l i n g s w i t c h f o l l o w e d by a MIM or i n t e r d i g i t a t e d h o l d c a p a c i t o r and an a m p l i f i e r . Due t o the low a c q u i s i t i o n t i m e , s w i t c h c o n f i g u r a t i o n v a r i a t i o n s a r e d e s i g n e d t o i n v e s t i g a t e the r e l a t i v e m e r i t of MESFET "guard g a t e s " (BSG1 and BSG2 i n F i g . 1.1) i n s u p p r e s s i n g s a m p l i n g s t r o b e f e e d t h r o u g h t o the s i g n a l p a t h . 3 The a m p l i f i e r i s , i n i t s open l o o p form, e s s e n t i a l l y a BFL i n v e r t e r , shown w i t h t h e ICDL m o d e l i n g s e c t i o n of Appendix A. Feedback i s a c h i e v e d by a d d i n g a n o t h e r MESFET(BFB) w i t h s o u r c e and d r a i n , i n p a r a l l e l w i t h the i n p u t MESFET as shown i n F i g . 1.1. The a m p l i f i e r was d e v e l o p e d t o e n a b l e c a s c a d i n g and i s t r e a t e d e x t e n s i v e l y by D.P. H o r n b u c k l e , R.L. Van T u y l and D.B. E s t r e i c h [ 1.5,1.6,1.7,1.8]. The MESFET i n t e g r a t e d s a m p l i n g s w i t c h and a m p l i f i e r b u i l t and t e s t e d by G. S. B a r t a and A. G. R o d e [ 1 . 3 ] , was f a b r i c a t e d i n SI p r o c e s s t e c h n o l o g y , w i t h t h e Nminus c h a n n e l i m p l a n t t h r o u g h a 100nm s i l o x f i l m y i e l d i n g V p=-1.5 V or V T*-0.8 V. The l i t h o g r a p h i c r e s o l u t i o n was ^um l i n e s and Ijxm gaps f o r t h e t r i p l e g a t e s t r u c t u r e r e s u l t i n g i n an "ON" F i g . 1.1 I n t e g r a t e d S a m p l i n g A m p l i f i e r B l o c k c o n f i g u r a t i o n . 4 resistance of 120S2 at Vgs=0 V for a 100Mm width, or 12000ft/Mm. The base RC input time constant calculated from this is 36ps as compared to the 65ps input time constant arrived at with 90% sampling efficiency with a 150ps strobe. If the system is considered as a simple RC network with a switch input step height and the capacitor i n i t i a l l y at V h 0 such that 5V=Vi-Vh0 then V h(t)=V i-6Ve" t/ r and 90% of 6V is lost in t=2.3r. This would imply an input time constant of 83ps for the switch, as compared to the measured 65ps. However the MESFET I^g is not linear with V^g and the strobe can be driven to 0.5* V providing more node charging current. The amplifier output stage diode stack employs diodes fabricated using gate metal on N* GaAs, reducing the series resistance(Rp S) per unit width of the forward biased stack diodes. A 150fF MIM capacitor was formed by using 100 nm of sputtered silicon nitride over an AuGe base plate resulting in a total of about 300fF sample node capacitance and a droop rate of 4 mV/ns. The use of external capacitors induces excessive ringing due to lead inductance[1.2]. The amplifier had a measured 3dB bandwidth of 1.1GHz with unity gain feedback and a measured system slew rate of 800 V / M S . The aim of the present project was to extend the work of Barta and Rode by modeling and implementing an ISAB in refractory self aligned gate(RSAG) technology using lithographic resolution of 1/im line and 2um gaps as shown in figure 1.2. As the RSAG process is a t-gate technology the 5 SI I urn line lum gap RSAG lum line 2um gap 3 - —•t= RSAG 0.2um line 0.2um gap Nplus T i W AuGe Schottky F i g . 1.2 T r i p l e Gate Switch Cross Sections. r e s u l t i n g submicrometer gate w i l l exhibit a reduced Cg S which should reduce the displaced charge during strobe operation and increase the strobe i s o l a t i o n to over 20dB. The input time constant should be reduced by decreasing the "ON" resistance per Mm with the s e l f aligned intergate Nplus implant. Considering the t r i p l e gate structures of figure 1.2 four series p a r a s i t i c resistance regions w i l l have a sheet resistance reduction of about 5 times which should reduce "ON" resistance by 15 to 20% compared to Barta and Rode. Thus the same width switch RSAG version of the SI t r i p l e gate ISAB should have a 55ps input time constant with about 25dB of strobe i s o l a t i o n . Strobe i s o l a t i o n could then be s a c r i f i c e d by reducing the node capacitance to bring the input time constant into the 25ps range. This implies that 6 o p e r a t i o n up t o 20GHz would be p o s s i b l e w i t h t h e t r i p l e g a t e c o n f i g u r a t i o n . D u a l and s i n g l e g a t e c o n f i g u r a t i o n s would have l o w e r i n p u t t i m e c o n s t a n t s , w h i c h i s the main p r i o r i t y of t h e work. The RSAG p r o c e s s has been de m o n s t r a t e d f o r d i g i t a l i n t e g r a t e d c i r c u i t s C 1 . 9 , 1 . 1 0 , 1 . 1 1 ] of short g a t e widthdOmn) and g a t e l e n g t h down t o l e s s than 0.1um u s i n g e l e c t r o n beam l i t h o g r a p h y (EBL). D e v i c e s w i t h 0.5/um g a t e l e n g t h a r e o b t a i n a b l e w i t h 300nm o p t i c a l l i t h o g r a p h y c a p a b l e of 1um l i n e w i d t h s t 1 . 4 ] . C o n s i d e r i n g t h e 0.2wm EBL t r i p l e g a t e of f i g u r e 1.2, "ON" r e s i s t a n c e would be reduced by about t e n t i m e s and C g S about 5 t i m e s compared t o t h e o t h e r RSAG c r o s s s e c t i o n . T h i s i m p l i e s t h a t o p e r a t i o n up t o s e v e r a l hundred GHz would be p o s s i b l e w i t h good strobe i s o l a t i o n . As t h e RSAG TiW or t u n g s t e n s i l i c i d e g a t e m e t a l i z a t i o n i s more r e s i s t i v e t h a n SI g a t e m e t a l i z a t i o n s RSAG s w i t c h g a t e s s h o u l d be d r i v e n a t one or more t - j u n c t i o n s , s i m i l a r t o power MESFETs. In o r d e r t o f a b r i c a t e RSAG MESFET ISABs w i t h low R p s S c h o t t k y d i o d e s f o r t h e a m p l i f i e r o u t p u t s t a g e and MIM c a p a c i t o r s , e i g h t mask l a y e r s were n e c e s s a r y . I n t e r d i g i t a t e d h o l d c a p a c i t o r s were used i n the ISAB l a y o u t s as an a l t e r n a t i v e t o t h e MIM t y p e and i f s u c c e s s f u l w i l l r e s u l t i n t h e e l i m i n a t i o n of one mask l a y e r and an i n c r e a s e i n y i e l d , w h ich would be s i g n i f i c a n t f o r t h e s i n g l e c h i p a c q u i s i t i o n system. Only the r e f r a c t o r y and S c h o t t k y m e t a l i z a t i o n s a r e shown i n f i g u r e 1.3 f o r c l a r i t y . 7 L i t h o g r a p h i c p l a t e p r o c e s s r e l a t e d l a y o u t v a r i a t i o n s a r e d e s i g n e d t o e n a b l e f a b r i c a t i o n of h i g h performance w o r k i n g d e v i c e s , w i t h m a n u f a c t u r a b l e t o l e r a n c e s . As such SI l a y o u t s w i t h ~\nm gate l e n g t h s and 2 , 3 , or 4nm s o u r c e and d r a i n t o g a t e gaps a r e combined w i t h s i x RSAG l a y o u t s w i t h 1 o r 2Mm g a t e mask l e n g t h s and 2, 3 , o r 4 /zm s o u r c e and d r a i n A mSm m I I * 61 8- • B S SI A • A A C-. 8% afi" a&" 8% • • A A D - SI 8ft • • A A P mmm e- 8% eft da * i eft £ £ £ A Fan H eft eft ela £ £ A G-s 8G> eft eft £ H§ - H * 9fr e& 8% da e& eft • JJL a 1 A 8- 8ft r+::+ j + + 4- M • • V • J A e- 8ft eft II K A 9- SB* 8- 6- M « « 6! 81 1 • L A B • A" •I >••» fill va •'• • =. 1 1 2 3 4 5 6 7 8 9 10 F i g . 1 . 3 O v e r a l l l a y o u t p a t t e r n . 8 to gate gaps, for a total of nine basic MESFET variations. It was necessary to leave approximately 300MITI channels between the device die to enable nondestructive separation with a narrow blade saw, assuming a cutting channel of about 100 Mm and a chipping width of about 40Mm [ 1 . 1 2 ] . This requirement served to motivate compaction of the device pad frame in order to maximize the number of ISAB units in the lithographically optimal inner 60% of the overall pattern[1.13]. A modified pad frame may be necessary later in the discrete phase of the project to enable automatic probing. Conversely the one chip acquisition system would have minimal pad requirements enabling circuit compaction within the limits of the transmission line geometries. The f i r s t mask layer is used to control an alignment etch in the surface about 2Mm deep to provide a reference for a l l subsequent layers. The second layer provides holes through which to implant the active regions for MESFET channel characteristics (N~). The third layer provides a pattern for the t-gate top for the RSAG process, protecting regions of TiW from removal. The fourth layer provides an implant mask for the N+ regions. The f i f t h mask is for ohmic contact to the N+ regions and production of MIM bottoms and inductors over nonactivated substrate. The sixth layer is a positive overlay mask protecting the MIM insulator Si3N 4 dielectric from etching, (which could be eliminated). The seventh mask is for SI Schottky metalization providing a high quality 9 interface for N* diodes and MESFET gates. This metalization serves a dual purpose as the MIM capacitor top plate. The eighth mask defines openings which are to be gold plated to a few Mm for airbridge bodies and bonding pad thickening. The N~ mask can be used with negative photo resist for implant isolation if necessary. The overall pattern outer dimensions are approximately 8.8mm high by 9.2mm across. Test patterns for process calibration and device characterization are around the outer edge of the pattern. The devices are listed in table 1.1 with alphanumeric grid reference to figure 1.3. The trailing grid reference characters(L,R,T,B) refer to the l e f t , right, top and bottom of the addressed c e l l . Loc Item Description/Code A 1 diagnostic amplifier AORT2_9024 A 2 diagnostic amplifier AORR2_9024 A 3LT RD diagnostic diode 5Mm Lg A 3LB RD diagnostic diode 10Mm Lg A 3R RD diagnostic diode 3 M m Lg A 4 amplifier AFRT3_9024 A 5 amplifier AFRT3_9023 A 6 amplifier AFRT3_9022 A 7 switch R2_40_1_2 A 8 switch R3_60_1_3 A 9L switch RO0_1_2 A 9R L C cal ibrat ion inductor test B 1 diagnostic amplifier AORT3_9024 B 2 diagnostic amplifier AORR3_9024 B 3LT TD diagnostic diode 5Mm Lg B 3LB TD diagnostic diode 10̂ m Lg B 3R TD diagnostic diode 3Mm Lg B 4 amplifier AFRT3_9014 B 5 amplifier AFRT4_9014 B 6 amplifier AFRR3_9012 B 7 switch R3_60_1_2 B 8 100Mm test FET SF_100_1_3 B 9L 100Mm test FET SF 100 1 4 10 B 9R 100Mm t e s t FET RF_100_2_4 B 10 fa t FET RSAG normal C 1 inductor l a r g e center C 2 switch R2 60 2 2 C 3 ISAB RM16R924T3 C 4 a m p l i f i e r AFRT3 9013 C 5 a m p l i f i e r AFRT4 9013 C 6 a m p l i f i e r AFRR3~9013 C 7 ISAB RM16R922T3 C 8 1 0 0 M m t e s t FET SF 100 1 2 C 9L 100**m t e s t FET RF 1 0 0 ~ 1 4 C 9R 100t*m t e s t FET RF~100~2_3 C 10 fa t FET RSAG no Nplus D 1 inductor small center D 2 switch R3 60 2 4 D 3 ISAB RMT6R923T3 D 4 a m p l i f i e r - AFRT3 9012 D 5 a m p l i f i e r AFRR2~6012 D 6 a m p l i f i e r AFRR2~6013 D 7 alignment mark D 8 1 0 0 M m t e s t FET RF 1 0 0 1 2 D 9L 100Mm t e s t FET RF 100~1 3 D 9R 1 0 0 M m t e s t FET RF_100~2~2 D 10 fa t FET SI on Nplus E 1 stepped r e s i s t o r TiW 3 step E 2 switch R1 60 2 2 E 3 ISAB RM16R914T3 E 4 ISAB RM16R913T3 E 5 ISAB SI3S912T3 E 6 ISAB SI2S912T3 E 7 ISAB SI1S912T3 B 8 '-gate FET RF 236 1 4 E 9L ff-gate FET SF 236 1 2 E 9R "•-gate FET RF_236_2_4 E 10 fa t FET SI normal F 1 stepped r e s i s t o r TiW 3 step F 2 switch R3 60 1 4 F 3 ISAB RI16R913T4 F 4 ISAB RI16R912T3 F 5 ISAB RI34R612T3 F 6 ISAB RI36R912T3 F 7 ISAB RI36R913T3 F 8 ff-gate FET RF 236 1 3 F 9L ff-gate FET SF 236~1~3 F 9R "•-gate FET RF~236~2_3 F 10 fa t FET SI~on both G 1L i s o l a t i o n monitor l a t e r a l 10Mm by 150mi gap G 1R i s o l a t i o n monitor v e r t i c a l G 2 switch R2 60 1 2 G 3 ISAB RI16R913T3 G 4 ISAB RI16R912R3 G 5 ISAB RI26R912T3 G 6 ISAB RI26R913T3 G 7 ISAB SI1S913T3 G 8 ff-gate FET RF 236 1 2 G 9L "•-gate FET SF 236~1~4 G 9R "•-gate FET RF 236~2 4 11 G 10 i s o l a t i o n monitor l a t e r a l H 1 f a t FET RSAG normal H 2 sw i t c h R3 40 1 2 H 3 ISAB RI26R922T3 H 4 ISAB RM16R912T3 H 5 ISAB SI3S913T3 H 6 ISAB SI2S913T3 H 7 ISAB SI1S914T3 H 8 dual gate FET RMPR 1 2 H 9L dual gate FET SMPR 1 2 H 9R dual gate FET RMPR~2~2 H 10 i s o l a t i o n monitor v e r t i c a l I 1 f a t FET RSAG no Nplus I 2 swi t c h R1 60 1 2 I 3 ISAB RI16R924T3 I 4 alignment mark I 5 ISAB RI16R914T4 I 6 3 amp o s c i l l a t o r OFRT39013 I 7 power FET dfet-500Mm I 8 dual gate FET RMPR 1 3 I 9L dual gate FET SMPR 1 3 I 9R dual gate FET RMPR~2_3 I 10 meander AuGe J 1 f a t FET SI on Nplus J 2 sw i t c h R1 60 1 3 J 3 ISAB RI16R923T3 J 4 ISAB RI16R922T3 J 5 ISAB RI16R914T3 J 6 modulator M26R912T3 J 7L dual gate s w i t c h rm2 40 1 2 J 7R dual gate s w i t c h rm2 40 1~3 J 8 dual gate FET R M P R 1~4~ J 9L dual gate FET SMPR~1 4 J 9R dual gate FET RMPR_2_4 J 10 meander SI gate metal K 1 Fat FET SI on Nminus K 2 sw i t c h R1 60 2 3 K 3 swi t c h R3~60 2 2 K 4 sw i t c h R1 60 2 4 K 5 swi t c h R1 60 1 4 K 6 sw i t c h R2 60~1~4 K 7 sw i t c h R2 60 1~3 K 8 sw i t c h R2~60~2~4 K 9L sw i t c h R2 60 2 3 K 9R sw i t c h R3_60_2~3 L 1 f a t FET SI on both L 2T SD d i a g n o s t i c diode 5 M m L s L 2B SD d i a g n o s t i c diode 3 Men L s L 3 SD d i a g n o s t i c diode 10Mm L s L 4 a i r b r i d g e t e s t AuGe under b r i d g e L 5T t r a n s m i s s i o n l i n e on Nminus L 5B t r a n s m i s s i o n l i n e on both L 6 d i a g n o s t i c a m p l i f i e r AORT4 9024 L 7 d i a g n o s t i c a m p l i f i e r AORR4_9024 L 8T MIM c a p a c i t o r area 5 by 100*411 L 8B MIM c a p a c i t o r area 6 by 60Mm 12 L 9 T I n t e r d i g i t a t e d c a p a c i t o r MIM c a p a c i t o r t r a n s m i s s i o n l i n e 14 h a l f p a i r s 200^m long L 9B L 10 area 50,000Mm' on Nplus Table 1.1 Overall mask pattern die locations Device codes, for the most part, serve the dual purpose of CAD data base f i l e name and unit d e s c r i p t i o n . The switch i d e n t i f i c a t i o n code begins with the process type, 'R' for RSAG and 'S' for SI, followed by the number of gates, the gate width over the active region, the mask gate length and the source/drain to gate gap in Mm. The ir-gate FET code begins with the process type followed by 'F', the gate width over the active region, mask gate length and source/drain to gate gap. The dual gate FET code begins with the process type followed by the logo "MPR" of the target test f a c i l i t y , Microtel P a c i f i c Research, then mask gate length and source/drain to gate gap. For the amplifiers the f i r s t two characters i d e n t i f y configuration as open loop 'AO' or feedback 'AF' followed by the MESFET process type. The next two characters are the diode process type, 'T' for SI gate metal on Nplus, and the number of diodes in the stack. The f i r s t two of the l a s t four d i g i t s indicate the output stage MESFET width, followed by the mask gate length and source/drain to gate gap. The ISAB code st a r t s with the switch process type followed by the hold capacitor type, 'M' for MIM and 'I' for i n t e r d i g i t a t e d , the number of gates in the switch, a single d i g i t representation of the switch gate width(ie. 6 for 13 60um), t h e a m p l i f i e r MESFET p r o c e s s t y p e , a s i n g l e d i g i t r e p r e s e n t a t i o n of t h e o u t p u t s t a g e w i d t h d e . 9 f o r 90mn), the n s o u r c e / d r a i n t o gat e and i n t e r g a t e gap f o r b o t h t h e s w i t c h and a m p l i f i e r , and f i n a l l y t h e d i o d e p r o c e s s type and number of d i o d e s i n t h e s t a c k . 2. PROCESS DEFINITION, PARAMETER EXTRACTION AND MASK LAYOUT P r o c e s s p a r a m e t e r s r e q u i r e d f o r l a y o u t were e s t i m a t e d from p r e v i o u s work, then a d j u s t e d by c a l c u l a t i o n f o r c u r r e n t p r o c e s s r e q u i r e m e n t s . 2.0.1 PROCESS PARAMETERS T a b l e 2.1 r e p r e s e n t s a v e r a g e d d a t a from D i n d o [ 2 . 1 ] a t U.B.C. and S a d l e r [ 2 . 2 ] a t C o r n e l l U n i v e r s i t y , c o n c e r n i n g S i i o n i m p l a n t e d p r o c e s s i n g of LEC GaAs. Parameter Value Source R s i 3 - io« « / • [2.1] Qi 2.2 '10'' ions/cm J [2.1] • i 100 keV [2.1] R s h t 1 1542 «/• [2.1] v T -1.97 V [2.1] V P 2.67 V [2.1] RP1 85 nm [2.1] A R P 1 44.2 nm [2.1 ] W 0 114 nm [2.1] W1 244 nm [2.1] Nmax1 1.27-10" [2.1] Q2 2-10" ions/cm' [2.2] *2 150 keV [2.2] R s h t 2 320 [2.2] R p 2 110 nm [2.2] A R p 2 96 nm [2.2] Nmax2 5.2-10" [2.2] Nplus to AuGe P c 1 65 tt/«nJ [2.2] AuGe to TiW P c 2 78 n/Mnl [2.2] T a b l e 2.1 P r o c e s s P arameters 14 15 2.1 PROCESS DEFINITION P l a t e d e f i n i t i o n s used f o r f a b r i c a t i o n ( T a b l e 2.2) a r e a consequence of ISAB f e a t u r e s and t h e p r o c e s s s t e p s t o b u i l d them. The p l a t e s can be used w i t h d i s c r e t i o n t o i n c l u d e or omit d e v i c e f e a t u r e s f o r a g i v e n p r o c e s s r u n . P l a t e Name 1N A l i g n 2N Nminus 3N TiW 4N Nplus 5N AuGe 6P D i e l e c t r i c 7N S c h o t t k y 8N ' A i r b r i d g e D e s c r i p t i o n A l i g n E t c h p a t t e r n f o r subsequent l a y e r s . The Nminus implant i s the same f o r a l l FBTs and Diodes a c t i v e r e g i o n . D e f i n e s t - g a t e and a l l TiW not e t c h e d . D e f i n e s the Nplus implant window a l l o w i n g s e l e c t i v e FET f a b r i c a t i o n . D e f i n e s ohmic c o n t a c t s and MIM c a p a c i t o r bottoms. Si3Ng c a p a c i t o r d i e l e c t r i c i s etched back t o PR i s l a n d s . S c h o t t k y SI FET, TD diode m e t a l , MIM tops and a i r b r i d g e f o o t i n g . A i r b r i d g e body, connector run and bonding pad t h i c k e n i n g . T a b l e 2.2 P r o c e s s P l a t e s The p l a t e s a r e d e s i g n a t e d by t h e i r p l a t e name i n t h e f o l l o w i n g p r o c e s s l i s t i n g . The l e t t e r "N" or "P" f o l l o w i n g t h e p l a t e number c o r r e s p o n d s t o p o s i t i v e or n e g a t i v e i n terms of r e l a t i o n of t h e r e s i d u a l p h o t o r e s i s t on the w a f e r , u s i n g p o s i t i v e p h o t o r e s i s t , t o t h e e n c l o s e d l a y e r on t h e CAD s t a t i o n s c r e e n . "N" r e f e r s t o no p o s i t i v e p h o t o r e s i s t ( P R ) l e f t i n t h e e n c l o s e d a r e a and ."P" r e f e r s t o PR r e m a i n i n g i n t h e e n c l o s e d a r e a , b e i n g d e v e l o p e d away e l s e w h e r e . 16 2.1.1 PROCESS LISTING The process allows production of both SI and RSAG devices concurrently, specifically allowing the use of low resistance two implant (TD) type diodes for RSAG amplifiers. As process results w i l l be optimized for a given subprocess individual ISAB units were constructed from components of the same type with the notable exception of the diode stack. The RSAG process should be optimized with respect to ion implantation, TiW thickness, and plasma or reactive ion etch parameters, as a result of the 1 and 0 . 5 M m mask gate lengths, only one may be made optimal on a given wafer run. These fabrication parameters should be optimized for switch transient characteristics as the main priority as long as this is consistent with amplifier operation and process yield. Bevelling was found to be necessary on test pieces for reducing photoresist edge bead height. If the bevelling is omitted increased mask to surface gap results in loss of line width control and rectangular edge profile as seen in figure 2.1. Process steps 30 to 57 are similar to those developed for MMIC manufacturing^.3,2.4]. Problems with implant activation uniformity and dislocations due to handling are expected[2.5,2.6]. Step D e s c r i p t i o n 1 Wafer b e v e l l i n g ( t e s t p i e c e s o n l y ) and s u r f a c e l a y e r r e m o v a l : F i g . 2.1 N o n b e v e l l e d PR edge p r o f i l e , no c h l o r o b e n z e n e soak. - d e p o s i t s i l i c o n n i t r i d e o r A l o v e r new w a f e r - s c r i b e and b r e a k w a f e r a s d e s i r e d - s p i n on p h o t o r e s i s t a t low rpm -mount p i e c e s t o be b e v e l l e d w i t h beeswax on g l a s s s l i d e o r aluminum b e v e l l i n g f i x t u r e f o r q u a r t e r s - b e v e l w a f e r e d g e s u s i n g 1.0**m a l u m i n a p o l i s h i n g compound on p o l i s h e r , h e a t i n g beeswax on h o t p l a t e t o r o t a t e 18 -remove PR, beeswax and alumina i n b o i l i n g acetone -use hot acetone then t r i c h l o r o e t h y l e n e f o l l o w e d by M i c r o s t r i p t o remove r e s i d u e , then r i n s e i n DI water -remove p r o t e c t i v e l a y e r w i t h HF - 1 % Alconox s o l u t i o n -DI water r i n s e - F i r s t e t c h s o l u t i o n : 5:NH4OH 2:H 20 2 240:DI -DI water r i n s e - B u f f e r e d HF -10% NH4OH -DI water r i n s e - N i t r o g e n blow dry 2 P h o t o r e s i s t d e p o s i t i o n for alignment etch - P h o t o r e s i s t t h i c k n e s s : 1.5Wn 3 P h o t o r e s i s t p a t t e r n exposure for alignment etch - P l a t e : A l i g n -Mask to PR method: vacuum contact 4 P h o t o r e s i s t develop f o r alignment etch -Developer type MF-316 -Spray a p p l i c a t i o n -DI water r i n s e 5 Alignment etch of GaAs surface -Etch s o l u t i o n : 5:NH4OH 2:H 20 2 240:DI 6 P h o t o r e s i s t removal - B o i l i n g acetone - B o i l i n g isopropanol 7 P h o t o r e s i s t d e p o s i t i o n for Nminus implant - P h o t o r e s i s t t h i c k n e s s : 1.5Mm 8 Ph o t o r e s i s t pattern exposure for Nminus implant - P l a t e : Nminus -Mask to PR method: depends on work piece 9 P h o t o r e s i s t develop f o r Nminus implant -Developer type: MF-316 -Spray a p p l i c a t i o n -DI water r i n s e 10 Nminus Implant -Species: S i 2 ^ -Energy: *^ keV -Dose: Qi ions/cm' -Wafer t i l t : 11° -Wafer r o t a t i o n : 22° F i g . 2.2 Bevel led p r o f i l e with chlorobenzene 11 P h o t o r e s i s t removal -Hot M i c r o s t r i p * T O S h i p l e y L t d . - B o i l i n g acetone - B o i l i n g i s o p r o p a n o l 12 L i g h t c l e a n i n g e t c h - E t c h s o l u t i o n : 1:NH4OH 1:H 20 2 240:DI -DI water r i n s e - B u f f e r e d HF -10% NH4OH -DI water r i n s e - N i t r o g e n blow dry 13 R e f r a c t o r y metal d e p o s i t i o n -Method: r f s p u t t e r , Ar atmosphere, TiW -Pr e s s u r e 33 mTorr -RSAG t h i c k n e s s o p t i m i z a t i o n h f 14 R e f r a c t o r y metal s u r f a c e c l e a n i n g - B u f f e r e d HF -DI water r i n s e - N i t r o g e n blow dry 15 P h o t o r e s i s t d e p o s i t i o n f o r t - g a t e mask - P h o t o r e s i s t t h i c k n e s s : 1.5Wn - C r i t i c a l : prebake t o remove water t r a c e s . -Spin on -Softbake 16 P h o t o r e s i s t p a t t e r n exposure f o r t - g a t e - P l a t e : TiW -Mask t o PR method: vacuum c o n t a c t Nminus Implant vs. Depth 20 min. annoal. 60* acflv* D*pth (nm) a implanted + annaated © activated g. 2.3 Nminus implant profile F i g . 2 .4 SEM photograph of alignment 17 P h o t o r e s i s t develop f o r t - g a t e -Chlorobenzene soak -Developer type: MF-312 -Immersion -DI water r i n s e 18 T-gate top metal d e p o s i t i o n - D e p o s i t i o n method: slow e v a p o r a t i o n 19 P h o t o r e s i s t removal and t- g a t e l i f t o f f - B o i l i n g acetone - B o i l i n g i s o p r o p a n o l 20 R e f r a c t o r y metal undercut e t c h - E t c h method: plasma or RIE -Plasma c o m p o s i t i o n : C F 4 -RSAG e t c h o p t i m i z a t i o n t , A fp, A j r 21 P h o t o r e s i s t d e p o s i t i o n f o r Nplus implant - P h o t o r e s i s t t h i c k n e s s : 1.5MB 22 Fig. 2.5 SEM photograph of 1/um sampling gate before l i f t o f f 22 P h o t o r e s i s t p a t t e r n exposure f o r Nplus implant - P l a t e : Nplus -Mask to PR method: vacuum c o n t a c t 23 P h o t o r e s i s t develop f o r Nplus implant -Developer t y p e : MF-316 -Spray a p p l i c a t i o n -DI water r i n s e 24 Nplus implant - S p e c i e s : S i 2 ^ - O p t i m i z a t i o n f o r L G = 1 **m -Energy: * 22 k e V -Dose: Fig. 2.6 SEM Photograph of 1jim gate after l i f t o f f . Q22 ions/cm* -Wafer t i l t : 11° -Wafer r o t a t i o n : 22° - O p t i m i z a t i o n f o r L G • 0.5^m -Energy: * 2 1 fceV -Dose: Q21 ions/cm' -Wafer t i l t : 11° -Wafer r o t a t i o n : 22° 25 P h o t o r e s i s t removal -Hot M i c r o s t r i p S h i p l e y L t d . - B o i l i n g acetone - B o i l i n g i s o p r o p a n o l 26 T-gate top removal 24 -Wet e t c h s o l u t i o n : HC1 -DI water r i n s e - N i t r o g e n blow dry 27 S i l i c o n n i t r i d e b l a n k e t d e p o s i t i o n -Plasma p r e c l e a n u s i n g : NH3 -Plasma c o m p o s i t i o n : He:500 seem SiH 4:550 seem, NH3:37.6 seem 28 Implant anneal - f u r n a c e : 30 min. 800° C 29 S i l i c o n n i t r i d e removal -Wet e t c h s o l u t i o n : HF -DI water r i n s e - N i t r o g e n blow dry 30 P h o t o r e s i s t d e p o s i t i o n f o r AuGe - P h o t o r e s i s t t h i c k n e s s : 1Mm 31 P h o t o r e s i s t p a t t e r n exposure f o r AuGe - P l a t e : AuGe -Mask t o PR method: vacuum c o n t a c t 32 P h o t o r e s i s t develop f o r AuGe -Chlorobenzene soak -Developer type MF-312 -Immersion -DI water r i n s e 33 AuGe d e p o s i t i o n - D e p o s i t i o n method: e v a p o r a t i o n 34 P h o t o r e s i s t removal and AuGe l i f t o f f - B o i l i n g acetone - B o i l i n g i s o p r o p a n o l 35 A l l o y AuGe t o Nplus GaAs - O p t i m i z a t i o n : furnace or r a p i d thermal a l l o y 36 Test process monitors enabled at t h i s stage I s o l a t i o n leakage TiW step r e s i s t o r AuGe ohmic meander Tran s m i s s i o n l i n e s RSAG t e s t MBSFBTs RD t e s t diodes 37 D e p o s i t i o n of MIM c a p a c i t o r d i e l e c t r i c : Si3N 4 -Plasma p r e c l e a n u s i n g : NHj - D e p o s i t i o n method: plasma -Plasma c o m p o s i t i o n : He:500 seem SiH 4:550 seem NH3:37.6 seem 38 P h o t o r e s i s t d e p o s i t i o n 813X4 e t c h - P h o t o r e s i s t t h i c k n e s s : 1.5wn -Spin on -Softbake 39 P h o t o r e s i s t p a t t e r n exposure f o r MIM d i e l e c t r i c - P l a t e : D i e l e c t r i c -Mask t o PR method: vacuum c o n t a c t 40 P h o t o r e s i s t develop f o r MIM d i e l e c t r i c -Developer type: MF-316 -Spray a p p l i c a t i o n -DI water r i n s e 41 D i e l e c t r i c E t c h to PR i s l a n d s - Etch S o l u t i o n 20% HF - B u f f e r e d HF -DI water r i n s e 42 P h o t o r e s i s t removal and l i f t o f f - B o i l i n g acetone - B o i l i n g i s o p r o p a n o l 43 P h o t o r e s i s t d e p o s i t i o n f o r S c h o t t k y m e t a l i z a t i o n - P h o t o r e s i s t t h i c k n e s s : 1̂ m -Spin on -Softbake 44 P h o t o r e s i s t p a t t e r n exposure Fig. 2.7 Cross Section of MIM 26 - P l a t e : Schottky -Mask to PR method: vacuum contact 45 P h o t o r e s i s t develop for Schottky m e t a l i z a t i o n -Developer type: MF-312 -Immersion -DI water r i n s e 46 Schottky m e t a l i z a t i o n d e p o s i t i o n -Deposition method: slow evaporation 47 P h o t o r e s i s t removal and m e t a l i z a t i o n l i f t o f f - B o i l i n g acetone - B o i l i n g isopropanol 48 P h o t o r e s i s t d e p o s i t i o n f o r a i r b r i d g e f o o t i n g - P h o t o r e s i s t t h i c k n e s s : 1.5Mm 49 P h o t o r e s i s t pattern exposure for a i r b r i d g e f o o t i n g - P l a t e : Schottky -Mask to PR method: standard contact -Exposure wavelength: -Exposure 50 P h o t o r e s i s t develop for a i r b r i d g e f o o t i n g -Developer type: MF-316 -Spray a p p l i c a t i o n -DI water r i n s e 51 D e p o s i t i o n of a i r b r i d g e f o o t i n g and p l a t e conduction metal -Method: r f sputt e r , Ar atmosphere, Au 3 nm 52 P h o t o r e s i s t d e p o s i t i o n for a i r b r i d g e body - P h o t o r e s i s t t h i c k n e s s : 1.5wn 53 P h o t o r e s i s t pattern exposure for a i r b r i d g e body - P l a t e : A i r b r i d g e -Mask to PR method: standard contact 54 P h o t o r e s i s t develop for a i r b r i d g e body -Developer type MF-316 -Spray a p p l i c a t i o n -DI water r i n s e 55 Gold p l a t e a i r b r i d g e body - e l e c t r o d e s on exposed edge Au - p l a t e to few Mm -DI water r i n s e 56 P h o t o r e s i s t removal and p l a t i n g m e t a l i z a t i o n l i f t o f f - B o i l i n g acetone - B o i l i n g isopropanol 27 57 W a f e r / S l i c e c o m p l e t e d With respect to step 20, plasma etching has a vertical to lateral etch rate vv-):v^1 of about 15:1 whereas RIE is 18:1. Referring to figure 2.8 MESFET high frequency performance improvement could be achieved by gate width resistance reduction and capacitance per unit width reduction by maximizing the TiW cross section available for conduction and minimizing the Schottky contact length. As the t-top should remain firmly in place for subsequent operations df t, the final dimension of the TiW top, should be maximized with respect to df^, the final dimension of the TiW bottom. The t-top, i n i t i a l l y hfc^ thick and d t^ wide should have Rp+3ARp=ht£ thickness and kdf D=d t£, where k is in the order of 2, after etching to prevent 99% of the implant from reaching the channel[2.2]. Assuming the t-top material v v2:v^2 ratio is the same as TiW and the etch rates of significantly less magnitude the approximate maximum TiW thickness (hj) can be calculated for the two mask line widths and both etch processes. Taking as bias B=(dti-dt£)/2 - df t and the degree of anisotropy Aj = 1 -VQ_ ̂ /Vv -| as Af=1-B/2hj after Mogab[2.7] then d f t=d m-(1-A f)2h f when etched to completion, where d m is the mask gate width and at completion ) 28 S I 1 2 RSAG1 2 RSAG2_2 EM Nminus • Nplus TiW AuGe Schottky. F i g . 2.8 MESFET Gate Cross Sections. dfj 3=d m. If etching continues u n t i l the base i s tedm, or les s , as required for RSAG df t c«df t-&d m=ted m-(1-A f)2h f where d f t c i s the c r i t i c a l TiW top width l e f t to support the t-top through subsequent operations. Choosing d f t c as 0.9dfb c, where d f ^ ^ d j j , corresponds to the Schottky contact width, for maximum t-top support, l i m i t s TiW thickness to h f*0.025d m/[(1-A f)]. Neglecting t-top etching hf = 0.025d mv vi/vi -j or about 0.45itm for RIE and 0.37itm for plasma etching of a 1itm d m t-top. For dm=2Mm a maximum 0.75um of TiW can be used with the plasma etch and 0.9um 29 with RIE. Over e t c h i n g produces a s h o r t e r gate l e n g t h at the r i s k of l o s i n g the t - t o p s . 3. SCHOTTKY DIODE PARAMETER EXTRACTION AND LAYOUT The a m p l i f i e r o u t p u t s t a g e d i o d e s t a c k r e q u i r e s d i o d e s which p r o v i d e v o l t a g e l e v e l s h i f t i n g w i t h r e a s o n a b l e t r a n s i e n t p e r f o r m a n c e , compact s i z e and r e l i a b l e f a b r i c a t i o n . Comparing t h e TD and RD s t r u c t u r e s o f f i g u r e o) TO Type [ . . ' [ 'semi-insulating GaAs III] Nminus ; mW TiW B Sdnifcy • Nplus mi AuGe; : : : : : b) RD Type : : : : : : : : F i g . 3.1 S c h o t t k y d i o d e c r o s s s e c t i o n s . a) TD S c h o t t k y g a t e m e t a l on Nplus+Nminus b) RD RSAG p r o c e s s 30 31 3 . 1 , where the "dot g r i d " i s 1/im f o r the c r o s s s e c t i o n s and 10jum f o r the a m p l i f i e r stack top views, the TD type diode used by Barta and Rode [ 1 . 2 ] i s more compact but at the expense of i n c r e a s e d c a p a c i t a n c e when compared to the RD type. In the forward b i a s e d mode of the a m p l i f i e r stack the d e p l e t i o n width W d i m i n i s h e s as the a p p l i e d v o l t a g e approaches V ^ . The major t r a n s p o r t process i s due to m a j o r i t y c a r r i e r s t u n n e l i n g from the GaAs under the d e p l e t i o n r egion over the p o t e n t i a l b a r r i e r i n t o the m e t a l [ 3 . 1 ] . Thermionic emission theory i s adequate f o r high m o b i l i t y semiconductors and r e s u l t s i n equation 3 - 1 , [ 3 . 1 ] . I s = SA**T 2exp ( - q 0 B/kT) [ 3 - 1 ] For GaAs the Richardson constant changes from low to h i g h f i e l d c o n d i t i o n s at E s as the e f f e c t i v e e l e c t r o n mass changes due to s c a t t e r i n g i n t o the upper v a l l e y of the conduction band. The h i g h f i e l d c o n d i t i o n s e t s i n at about 3kV/cm, which i n c o n s i d e r a t i o n of the d e p l e t i o n width at zero b i a s f o r the N " implant of t a b l e 2 .1 holds f o r a p p l i e d v o l t a g e s above about 0 . 0 3 . As such the value of A** i s taken as 144 A/cm 2/K 2 [ 3 . 1 ] . The Schottky diode b a r r i e r t r a n s i t time(TT) f o r SPICE i s approximated as W 0/2i> s, where i> s=M nE s and E s i s taken as 3200 V/cm and Mn i s a d j u s t e d f o r doping l e v e l . 32 The p a r a s i t i c s e r i e s r e s i s t a n c e ( R p S ) p e r u n i t w i d t h o f t h e d i o d e d e t e r m i n e s t h e t o t a l w i d t h r e q u i r e d f o r t h e a m p l i f i e r d i o d e s t a c k , n e g l e c t i n g s u b s t r a t e s h u n t r e s i s t a n c e . As c a n be s e e n f r o m t h e c r o s s s e c t i o n s i n f i g u r e 3.1 Rp S=R c+R^+R s, where R c i s t h e c o n t a c t r e s i s t a n c e , R^ i s due t o t h e gap a n d R s i s t h e a v e r a g e r e s i s t a n c e u n d e r t h e d e p l e t i o n r e g i o n . R s i s c a l c u l a t e d a f t e r K e l l n e r , E n d e r s , R i s t a w a n d K n i e p k a m p [ 3 . 2 ] v i a e q u a t i o n 3-2. R s ~ 3 ^ R s h t [ 3 - 2 ] Where R s h t *-s t a k e n a s t h e s h e e t r e s i s t a n c e o f t h e i m p l a n t u n d e r t h e S c h o t t k y m e t a l . R^ i s t a k e n a s t h e s h e e t r e s i s t a n c e b e t w e e n t h e ohmic a nd S c h o t t k y b a r r i e r c o n t a c t s . R c i s c a l c u l a t e d a f t e r B e r g e r [ 3 . 3 ] f o r a *\nm s t r i p a s R c = i / [ R C V ( R S S ) ] where R c v i s p c ^ ( c o n t a c t a r e a ) a n d R s s i s R s h t 2 ( l e n g t h ) / ( w i d t h ) . The t o t a l s e r i e s r e s i s t a n c e due t o t h e R p S p e r u n i t w i d t h f o r t h e d i o d e t y p e i s d i v i d e d by t h e a r e a f a c t o r t a k e n a s w i d t h i n c l u d e d i n t h e a m p l i f i e r d i o d e s p e c i f i c a t i o n s i n A p p e n d i x B. A d e f a u l t v a l u e f o r t h e S c h o t t k y t o ohmic m e t a l s p a c i n g o f 4jum i s u s e d f o r b o t h d i o d e t y p e s . V e l o c i t y s a t u r a t i o n i s a c h i e v e d i n t h e gap a t a p p r o x i m a t e l y 1.2 V a c r o s s t h e gap, o r 2 V a c r o s s t h e d i o d e , o r a b o u t 1.7 V f o r a 3Mm gap. B o t h a r e a d e q u a t e however t h e 4Mm gap b e i n g more r e l i a b l e w i t h r e s p e c t t o p r o c e s s y i e l d [ 3 . 4 ] . O n l y t h e d i o d e s t a c k number 33 and width is changed to match the diode stack to amplifier cir c u i t requirements. Diodes were model characterized per unit width for standard gaps of 3 and 4 Mm and Schottky metal length of 3 Mm from alignment and capacitance considerat ions. SPICE model Schottky diode tra i l i n g numbers are Lg ap. SPICE input deck format specifies RS as RpS in the following diode models. .MODEL RD4 D(IS=0.31E—12, RS=3206, N=1.18, TT=0.45PS, + CJO=3.85E-15, VJ=0.72, EG=1.42, BV=8, IBV=1E~3) .MODEL TD4 D(IS=0.31E-12, RS=1744, N=1.1, TT=0.59PS, + CJO=8.02E-15, VJ=0.72, EG=1.42, BV=8, IBV=1E~3) The cutoff frequency ( f c= 1/( 27rRpsC j) ) is about 8.8 and 11.1 GHz for the TD and RD types, respectively, with a bias of 0 V. Equation 3-3 gives the diode I-V characteristic with the effect of RpS. V = IR p s + (nkT/q)ln(l/l s + 1) [3-3] Using data in Table 2.1 and referring to Figure 3.1 the parameters for a iMm wide diode slice were constructed for the two types and used for amplifier stack layout calculations in section 6. Ideality factor n is taken as 1.18 for RSAG and 1.1 for SI. Schottky interface problems were assumed negligible for the layout calculations however can be determined from the FAT FETs and accounted for later in simulations[3.5]. 4. MESFET PARAMETER EXTRACTION AND LAYOUT The major l i m i t a t i o n s t o MESFET f a b r i c a t i o n u s i n g mask c o n t a c t o p t i c a l l i t h o g r a p h y a r e minimum l i n e w i d t h and worst c a s e a l i g n m e n t . 4.1 ALIGNMENT LIMITATIONS F a c t o r s t h a t dominate l a y o u t a r e i n t e r l a y e r a l i g n m e n t skew and minimum l i n e w i d t h and l i n e t o gap r a t i o of mask l i t h o g r a p h y p r o v i d e d by t h e p l a t e m a n u f a c t u r e r . The l i n e w i d t h l i m i t of t h e c u r r e n t mask i s 1/xm and t h e l i n e t o gap r a t i o was f i x e d a t 1:2 f o r mask p r o d u c t i o n c o s t , f a b r i c a t i o n and a l i g n m e n t r e a s o n s . I f t h e mask s e t has a t o l e r a n c e of 8 j (±0.1«xm) [4.1] l a t e r a l p o s i t i o n w i t h i n and ±0.4/xm ( 6 L ) between l a y e r s and the a l i g n m e n t can be m a n u a l l y made t o ±0.5Mm ( 6 A ) under o p t i m a l c o n d i t i o n s [ 4 . 2 ] , a minimum s p a c i n g of $ j + S L + S A must be a l l o t t e d t o a v o i d c o n t a c t . A f u r t h e r m a r g i n must be a l l o w e d f o r l a t e r a l movement d u r i n g a l l o y i n g (8L A) w i t h t h e t o t a l e r r o r t i m e s a s a f e t y f a c t o r (S) t o a c c o u n t f o r t h e o p t i m i s t i c a l i g n m e n t a s s u m p t i o n , as i t i s a time consuming manual o p e r a t i o n and some m i s a l i g n m e n t may o c c u r d u r i n g t h e vacuum t r a n s f e r phase of t h e exposure o p e r a t i o n . S (6 I+8 L+ 6 A+ 6 L A ) = MINIMUM SEPARATION [4-1] T a k i n g 6 L A as 0.3/um and S as 1.5 g i v e s about 2(im minimum s e p a r a t i o n between l a y e r s , o r more c o n s e r v a t i v e l y 2.6/xm w i t h 34 35 S as 2 . Minimum s e p a r a t i o n w i t h i n a l a y e r can be reduced by t h e compounding e f f e c t of i n t e r l a y e r mask skew and l a t e r a l s p r e a d i n g r e s u l t i n g i n a minimum s e p a r a t i o n of l e s s t h a n "Idem. However p r e v i o u s e x p e r i e n c e a t U.B.C. has shown t h a t a 1iim i n t e r g a t e gap on a m u l t i p l e g a t e RSAG MESFET c a u s e s l i f t o f f problems i n s t e p 19 of s e c t i o n 2 . 1 . 1 , asymmetric plasma u n d e r c u t t i n g i n s t e p 20 [4 .3 ] and i s h i g h l y demanding of t h e c u r r e n t p l a t e m a n u f a c t u r i n g p r o c e s s [ 4 . 1 ] . 4 .1 .1 INTERLAYER ALIGNMENT MARKS To maximize a l i g n m e n t a c c u r a c y a s e t of a l i g n m e n t marks shown i n f i g u r e 4.1 were d e v e l o p e d . As t h e mask a l i g n e r i s c a p a b l e of l a t e r a l movement a t a m a g n i f i c a t i o n of 160X c o r r e s p o n d i n g t o a mask t o wafer gap of 20xtm, then an a l i g n m e n t c h e c k i n g o p e r a t i o n w i t h t h e mask and wafer a t a 3 Mm gap or under vacuum a s s i s t e d d i r e c t c o n t a c t , t h r e e l e v e l s of a l i g n m e n t mark a r e n e c e s s a r y . The f i r s t mark must a l l o w the o p e r a t o r t o a l i g n wafer t o mask o r i e n t a t i o n e a s i l y , f o r w h i c h a s i m p l e s t a c k e d s t r u c t u r e w i l l s u f f i c e ( c o r n e r b r a c k e t s i n f i g . 4 . 1 ) . The second mark s h o u l d a l l o w maximum a l i g n m e n t a c c u r a c y a t 160X m a g n i f i c a t i o n a t w h i c h the s m a l l e s t v i s i b l e f e a t u r e i s 1 .5Mm i n a f i e l d of a p p r o x i m a t e l y 200 by 2 0 0 M m . The proposed 0.5Mm a l i g n m e n t a c c u r a c y of the p r o c e s s can o n l y be o b t a i n e d under t h e s e c o n d i t i o n s by t a k i n g advantage of the symmetry d e t e c t i o n c a p a b i l i t y of the o p e r a t o r by b a l a n c i n g l i g h t and dark 3 6 Fig. 4.1 Alignment Marks fields[4.2] of greater than 1.5/im. As such 3 and 4Mm were taken as a 2nd level gaps. The third level mark should be able to take advantage of the 320X objective capability of detecting a 0.75Mm minimum feature[4.2] to check the second mark alignment under direct contact through a 1 to 2Mm photoresist layer with a depth of f i e l d of 3Mm and a frame of less than 100mn.The inner cross has a 1 or 2Mm gap to compensate the possible interference due to the photoresist, resulting in the multiple patterns for each layer. I n o r d e r t o accommodate t h e demands of a l i g n i n g t o the o r i g i n a l a l i g n m e n t e t c h , t h u s t o a v o i d any e r r o r t a c c u m u l a t i o n between l a y e r s , and check m e t a l t o m e t a l a l i g n m e n t , s e p a r a t e a l i g n m e n t marks were u s e d , i n c l u d i n g m e t a l o v e r l a y s of p r e v i o u s m e t a l d e p o s i t i o n s . The f a c t t h a t w i t h p o s i t i v e p h o t o r e s i s t t h e exposed a r e a t h r o u g h the c l e a r p o r t i o n of t h e mask i s s u b s e q u e n t l y d e v e l o p e d away means t h a t t o o b t a i n the l i g h t f i e l d symmetry f o r second l e v e l a l i g n m e n t t h e c l e a r a r e a must s u r r o u n d the p e r i p h e r y of the e t c h l i n e by 4Mm. T h i r d l e v e l a l i g n m e n t can be a c c o m p l i s h e d by a i n t e r n a l e t c h p e r i p h e r y w i t h a dark mask f i e l d 1/xm i n s i d e i t . 4.2 RSAG AND SELECTIVE IMPLANT PROCESS PARAMETER DIFFERENCES As i s a p p a r e n t from f i g u r e 4.2, RSAG d e v i c e s made w i t h the same l e v e l o f l i t h o g r a p h y as SI d e v i c e s s h o u l d have s u p e r i o r p erformance due t o re d u c e d g a t e l e n g t h and s o u r c e / d r a i n p a r a s i t i c r e s i s t a n c e . E q u a l l y a p p a r e n t though i s t h e f a c t t h a t RSAG p r o c e s s gate r e s i s t a n c e i s much h i g h e r l e a d i n g t o a l o s s of some of the g a i n e d b e n e f i t w i t h r e s p e c t t o t h e SI p r o c e s s . 4.2.1 SOURCE AND DRAIN RESISTANCE Source and d r a i n r e s i s t a n c e s a r e m i n i m i z e d t o m i n i m i z e the c h a n n e l t r a n s i t t i m e ( T ) and i n c r e a s e I D s a t a g i v e n V D g . R e f e r r i n g t o F i g . 4.2 i t can be seen t h a t R s and R D have s e v e r a l s e r i e s c o n t r i b u t i o n s . The 38 Fig. 4.2 Cross Section of MESFETs tr a i l i n g model numbers(ie. RSAG1_2) correspond to mask L G and L g a p . The gap resistance R S g a p or R D g a p is calculated by using the applicable Rgheet t i n 1 6 3 t^e number of squares in the gap, allowing for lateral diffusion during anneal in the RSAG case. This does not allow for alignment variations. Ohmic contact resistance is calculated after Berger[3.3]. For the purposes of compaction and layout regularity for a large number of circuit variations a 39 s t a n d a r d c o n t a c t l e n g t h of 20iim was s e l e c t e d , however some l a y o u t s a r e a d j u s t e d s l i g h t l y . 4.2.2 GATE PHASE SHIFT A " w e l l d e s i g n e d FET", w i t h r e s p e c t t o g a t e s e r i e s r e s i s t a n c e , has gat e m e t a l e v a p o r a t i o n o n t o t h i c k d o u b l e l a y e r p h o t o r e s i s t f o r l i t h o g r a p h i c a c c u r a c y w i t h r e l i a b l e l i f t o f f o f unwanted m e t a l from a t h i c k d e p o s i t i o n [ 2 . 4 ] . T y p i c a l l a y e r s a r e 300 nm of TiW topped by 0.7 (tn Au p r o d u c i n g a "mushroom g a t e " p r o f i l e . The t h i c k g o l d l a y e r i s n e c e s s a r y t o d e c r e a s e Rg per u n i t w i d t h a t h i g h f r e q u e n c y , m i n i m i z i n g g a i n d e g r a d a t i o n due t o t r a n s m i s s i o n l i n e and s k i n e f f e c t s [ 4 . 4 - 4 . 8 ] . The c u r r e n t g a i n of a MESFET depends on a u n i f o r m v o l t a g e a c t i n g a l o n g t h e c h a n n e K z a x i s ) . I f a phase s h i f t of t h e c o n t r o l s i g n a l o c c u r s a l o n g t h e w i d t h of the g a t e , the s o u r c e t o d r a i n f l o w o f e l e c t r o n s t h r o u g h the c h a n n e l v a r i e s w i t h Z. T h i s e f f e c t i s a r e s u l t of phase s h i f t due t o the t r a n s m i s s i o n l i n e c h a r a c t e r of the g a t e . A second m e t a l l a y e r f o r the TiW RSAG gat e has been at t e m p t e d by Sadler [ 2 . 2 ] t o make up f o r t h e d i s c r e p a n c y a p p a r e n t i n t a b l e 4 .1, l e a v i n g A l , N i , Au, and P t t - g a t e t o p s i n p l a c e d u r i n g a n n e a l i n g . The r e s u l t was " d r a s t i c i n t e r d i f f u s i o n and a l l o y i n g ... between t h e t o p m e t a l and the GaAs". W i t h t h i s i n mind we c o n s i d e r e d p o s t a n n e a l p r o c e s s i n g as t h e o n l y v i a b l e r e f r a c t o r y g a t e 40 s t r i p e r e s i s t a n c e r e d u c t i o n s t r a t e g y . M e t a l B u l k T h i n F i l m E s t i m a t e U n i t s A l Au T i W T i 0 . 3 w 0 . 7 2.56 2.44 41.00 5.60 16.22 5.12 4.88 82.00 11.20 74.61* jifl-cm MO-cm MO-cm Mfl-cm Mfi-cm T a b l e 4.1 T h i n f i l m r e s i s t i v i t y . ( * from [2.2]) A p o s t a n n e a l gate g o l d p l a t i n g p r o c e s s was c o n j e c t u r e d . An e x t r a f a b r i c a t i o n s t e p would be added where a temporary i n t e r c o n n e c t web would p r o v i d e p l a t i n g c u r r e n t t o t h e g a t e s . T h i s would cause e l e c t r o l y t i c p l a t i n g a c t i o n a t exposed a r e a s , but would r e q u i r e p r e c i s e l y a l i g n e d mask windows t o p r e v e n t unwanted p l a t i n g . A f t e r p l a t i n g t h e PR would be removed and a c i r c u i t s h i e l d i n g mask used t o e t c h t h e p l a t i n g c u r r e n t d i s t r i b u t i o n g r i d . The main problem w i t h t h i s p l a n i s p l a t i n g mask a l i g n m e n t and minimum l i n e w i d t h . A l i g n m e n t skew of 1.6/im i s e x p e c t e d , and t h e mask minimum l i n e w i d t h of 1um i s in a d e q u a t e f o r 0.5/xm RSAG gate l e n g t h s . I t has been d e m o n s t r a t e d by W o l f [ 4 . 3 ] t h a t the e f f e c t of g a t e m e t a l i z a t i o n r e s i s t a n c e i s p r o p o r t i o n a l t o b?, where b i s t h e g a t e w i d t h . As s u c h t h e d e s i g n p h i l o s o p h y of t h i s p r o j e c t has been t o maximize TiW t h i c k n e s s and the gate w i d t h w i t h r e s p e c t t o the maximum 41 frequency or pulse response required of the MESFET. Separate considerations are included for the switch of section 5 and the amplifier of section 6. 4.3 MESFET CAPACITANCE Capacitance due to the depletion layer(C Gg and C G D varies with the specific two dimensional geometry of the depletion region, which is dependent on V Gg and V Dg. C Dg is considered to be relatively independent of the depletion region and as such is treated as a constant. The SPICE 2[4.4] MESFET model proposed by Curtice[4.5] and realized by Sussman-Fort[4.6] models C Gg as variable and treats C G D as constant. Several other models have been published some of which are included in the references[4.7-4.11]. In the course of modeling ICDL and other logics(partial inclusion in appendix A) with the SPICE 2 MESFET model Abdel-Moteleb, Rutherford and Young[4.17] included a variable C G D for some of the simulation runs. The MESFET circuit model with an added shunt resistor, due to substrate conduction, appears in figure 4.3. A more accurate capacitance model has been proposed by Golid, Hauser and Blakey[4.13] of which the C G D portion has been included in a version of SPICE 2 (re: appendix B). 42 GATE RG CGS RS f F l I | CGD SOURCE• CDS II RSHUNT RD DRAIN MESFET CIRCUIT MODEL UITH SHUNT RESISTOR Fig. 4.3 MESFET c i r c u i t model 4.4 MESFET 1<xM SLICE PARAMETERS From the process definition and parameter estimation procedures nine MESFET SPICE models are maintained for cir c u i t evaluation. Figure 4.4 a) represents a typical industry standard MESFET configuration which is used as a process benchmark for comparison of our variations to each other and MESFETs currently being produced by several manufacturers. Figure 4.4 b) has a 1um dot grid superimposed on the magnified layout of the gate connect, as compared to the 100Mm dot grid of figure 4.4 a). DC characteristics are accumulated from the 100/zm test MESFET or 236 w-gate array of figure 1.2 with the use of a semiconductor parameter analyzer. 43 F i g . 4.4 a) 7r-Gate Layout The s i m u l a t e d I-V c h a r a c t e r i s t i c s a r e d i s p l a y e d f o r 100iim w i d t h s i n f i g u r e s 4.5 t o 4.7 f o r t h e n i n e v a r i a t i o n s . In t h e SPICE models below a l l w i d t h dependent c o n s t a n t s a r e per nm. SPICE GGSO and CGD a r e c a l c u l a t e d a t V G S and V D S = 0 V from t h e normal space charge e q u a t i o n 4-2. Comparing t h e measured r e s u l t s of Van T u y l and L i e c h t i [ 4 . 1 4 ] 44 F i g . 4.4 b) ff-Gate M a g n i f i e d C S c i s a p p r o x i m a t e l y e q u a l t o C G S u n t i l t he MESFET i s b i a s e d near V Q C * = 0 . 5 V where t h e measured C G g i s about 0.68C S G. From symmetry CGD i s e q u a l t o CGS under t h e s e c o n d i t i o n s . The SPICE s i m u l a t i o n then p r o c e e d s t o m o d i f y the i n i t i a l v a l u e s a c c o r d i n g t o e q u a t i o n s 4-3[4.5] and 4-4[ 4 . 1 3 ] . C s c = L Z [ q £ N ( x ) / 2 ( V B I - V G S - V F C H ) ] * [4-2] c G s ( v g s ) s = C G S 0 / [ 1 - V G S / V B I ] * [4-3] cGD< vgs' Vds>= C GD0/£ T - ^ G D l V g s - V d s ^ ^ G D ^ G 5 3 ( 1 - X G D 2 v g s ) [4-4] 45 RSAG1_4 TEST MESFET F i g 4.5 RSAG 0.5Mm I-V c h a r a c t e r i s t i e s RSAG2_2 TEST MESFET 2.4 la RSAG2_3 TEST MESFET RSAG2_4 TEST MESFET 4.6 RSAG lMm I-V characteristics SI1_3 TEST MESFET SI1_4 TEST MESFET Fig. 4.7 SI 1um I-V characteristics 48 The c o n s t a n t s f o r e q u a t i o n 4-4 a r e l i s t e d i n Appendix C as p a r t of the GASFET s u b r o u t i n e s o u r c e code. I d s i s e m p i r i c a l l y f i t t e d w i t h e q u a t i o n [4-5] a f t e r C u r t i c e [ 4 . 5 ] . I d s = / 5 ( V g s + V T ) i • ( 1 + X V d s ) t a n h ( o V d s ) [4-5] Where X i s the c h a n n e l l e n g t h m o d u l a t i o n f a c t o r and a i s the h y p e r b o l i c t a n g e n t f u n c t i o n p a r a m e t e r , o i s used t o f i t the l i n e a r r e g i o n and X t h e s l o p e of t h e s a t u r a t i o n r e g i o n . The t r a n s c o n d u c t a n c e parameter /J=Ip/V p* and V T a r e g e n e r a l l y d e t e r m i n e d by p l o t t i n g / I J J S V S « V G S a n c * a c c o u n t i n g f o r Rg and R D. I f d e v i c e s a r e not a v a i l a b l e j8 can be a p p r o x i m a t e d t h e o r e t i c a l l y a f t e r Chen and S h u r [ 4 . 1 5 ] . 0 = [ 2 e G a A s u s w 3 / [ A ( v P + 3 E m L 1 ) ] [ 4 _ 6 ] where A = [ 2 e G a A s V p ] / [ q Q a ] [4-7] and L 1 = L - 2 ^ s i n h - , { [ T K d ( V d s - V i s ) ] / [ 2 A E s ] } [4-8] and t h e v o l t a g e d r o p a c r o s s t h e c h a n n e l a t s a t u r a t i o n i s : V i s = [ E s L ( V g s - V T ) ] / [ E s L + V g s - V T ] [4-9] K d i s a p p r o x i m a t e l y 1 f o r s e l f a l i g n e d g a t e s and K d = A V / ( V d s - V i s ) f o r S I g a t e s where AV i s the " v o l t a g e drop a c r o s s p a r t of the h i g h f i e l d domain under t h e g a t e " . When 49 V G S = V B I the maximum V I S = ( E S L V P Q / ( E S L + V P Q ) and increase in I^g due to channel shortening is negligible for v c l s > v " i s + 2 volts at this point, /? can be considered independent [ 4 . 10 ] of V D S > > V i s + 2 at V G S = V B I . Q A is taken as the implant activation times the N~ dose for the purposes of i n i t i a l approximation. The following models are the result of layout and process calculations. .MODEL RSAG1_2 GASFET(VTO= -2, VBI=1.23, RG=4.97, ALPHA=2.3, + B E T A=3.1E-5, LAMBDA=0.055, CGS0=0.595FF, CGD=0.595FF, + CDS=0.0791FF, IS=2.07E-15, RD=1170, RS=1170, + TAU=0.71PS) .MODEL RSAG1_3 GASFET(VTO=-2, VBI= 1.23, RG=4.97, ALPHA= 2 . 3 , + BETA= 3.1E - 5 , LAMBDA=0.055, CGS0=0.595FF, CGD=0.595FF, + CDS=0.0738FF, IS= 2.07E-15, RD=1490, RS=1490, + TAU=0.71PS) .MODEL RSAG1_4 GASFET(VTO= - 2 , VBI=1.23, RG=4.97, ALPHA= 2 . 3 , + B E T A = 3.1E - 5 , LAMBDA=0.055, CGS0 = 0.595FF, CGD=0.595FF, + CDS=0.0714FF, IS= 2.07E-15, RD=1810, RS=1810, + TAU=0.71PS) .MODEL RSAG2_2 GASFET(VTO=~2 , V B I=1.23, RG=1.49, ALPHA= 2 . 3 , + B E T A = 2 . 6 1 E - 5 , LAMBDA=0.055, CGS0=1.19FF, CGD=1.19FF, + CDS=0.096FF, IS=4.13E-15, RD=1555, RS=1555, TAU=2.86PS) .MODEL RSAG2_3 GASFET(VTO=~2, VBI= 1.23, RG=1.49, ALPHA= 2 . 3 , + B E T A = 2 . 6 1 E - 5 , LAMBDA=0.055, CGS0=1.19FF, CGD=1.19FF, + CDS= 0 . 0 9 4 7 F F , IS=4.13E-15, RD=1875, RS=1875, TAU=2.86PS) .MODEL RSAG2_4 GASFET(VTO= - 2, VBI=1.23, RG=1.49, ALPHA= 2 . 3 , + B E T A=2.61E~5, LAMBDA=0.055, CGS0=1.19FF, CGD=1.19FF, + CDS=0 . 0 7 9 1 F F , IS=4.13E~15, RD=2195, RS=2195, TAU=2.86PS) .MODEL SI 1 _ 2 GASFET(VTO= - 2 , VBI=1.23, RG=0.13, ALPHA= 2 . 3 , + B E T A = 2 . 6 1 E ~ 5 , LAMBDA=0.055, CGS0=1.19FF, CGD=1.19FF, + CDS=0.096FF, IS= 4.13E-15, RD=3228, RS=3228, TAU=2.86PS) .MODEL S I 1 _ 3 GASFET(VTO=-2, VBI=1.23, RG=0.13, ALPHA=2.3, + BETA=2.61E-5, LAMBDA=0.055, CGS0=1.19FF, CGD=1.19FF, + CDS=0.0847FF, IS=4.13E-15, RD=4770, RS=4770, TAU=2.86PS) .MODEL SI1_4 GASFET(VTO= - 2 , VBI= 1.23, RG=0.13, ALPHA= 2 . 3 , + BETA=2.61E"5 , LAMBDA=0.055, CGS0=1.19FF, CGD=1.19FF, + C D S=0 . 0 7 9 1 F F , IS= 4.13E-15, RD=6312, RS=6312, 50 + T A U = 2 . 8 6 P S ) V f a i i s tak e n as 0 . 5 V + 0 B n a f t e r C u r t i c e [ 4 . 5 ] a l l o w i n g f o r a v o l t a g e d r o p a c r o s s r ^ i n t h e c o n d u c t i o n c h a n n e l under the g a t e . The t r a n s i t t i m e under the ga t e TAU i s used i n t h e model t o i n c l u d e t h e d e l a y e d e f f e c t of a change i n V g S on I j j g . I n the C u r t i c e [ 4 . 5 ] model i t i s a c o n s t a n t . TAU i s tak e n a t V^ s - 1 V, u s i n g a c o n s e r v a t i v e average low f i e l d m o b i l i t y of 3500 cm 2/V-s, a c r o s s t h e e f f e c t i v e c h a n n e l l e n g t h . T h i s v a l u e i s the n m o d i f i e d d u r i n g program e x e c u t i o n i n a p r o t o t y p e SPICE v e r s i o n by d i v i d i n g TAU by V^g+k, where k i s t o p r e v e n t d i v i s i o n by z e r o , t o produce an e f f e c t i v e t r a n s i t t i m e . 5. SWITCH CONSIDERATIONS AND LAYOUT F i g u r e 5.1 a) i s t h e l a y o u t f o r a t r i p l e g a t e RSAG1_2 s w i t c h w i t h a 100/zin d o t g r i d and f i g u r e 5.1 b) i s a m a g n i f i e d view of t h e g a t e r e g i o n . Assuming t h e e x i s t e n c e of a ground p l a n e a d i s t a n c e d under t h e m e t a l i z a t i o n , c i r c u i t F i g . 5.1 a) T r i p l e Gate S w i t c h Layout 51 52 F i g . 5.1 b) M a g n i f i e d T r i p l e Gate S w i t c h p a r a s i t i c s can be c a l c u l a t e d a f t e r Van T u y l , L i e c h t i , Lee and Gowen[5.1]. S w i t c h s a m p l i n g performance i n v o l v e s t h e combined e f f e c t of p u l s e edge p r o p a g a t i o n and r e f l e c t i o n i n the gate and c h a n n e l r e a c t i o n . I n a p u l s e modulated s h o r t c h a n n e l MESFET t r a n s i e n t b e h a v i o r can be s i m u l a t e d by a two d i m e n s i o n a l mesh model i n f r a c t i o n s of a p i c o s e c o n d such as performed by F a r i c e l l i , Fig. 5.3 Triple Gate Switch Distributed Model 54 F r e y and K r u s i u s [ 5 . 2 ] w i t h r e s p e c t t o d i g i t a l l o g i c . 5.1 THE SAMPLING CYCLE In a s a m p l i n g c y c l e the s w i t c h i s i n i t i a l l y h e l d a t or below p i n c h o f f by t h e s a m p l i n g p u l s e t r a n s m i s s i o n l i n e b i a s . The r i s i n g edge of t h e p u l s e ramps from V T t o Vj^-AV, where AV i s t o p r e v e n t f o r w a r d c o n d u c t i o n , i n t r . The v o l t a g e ramp p r o p a g a t e s down t h e g a t e t r a n s m i s s i o n l i n e and r e f l e c t s o f f the u n t e r m i n a t e d end. I n t h e c h a n n e l t h e p o s i t i v e gate p u l s e c a u s e s f i e l d s t o withdraw from t h e a c t i v e l a y e r , d r awing m a j o r i t y c a r r i e r s from t h e s o u r c e and d r a i n towards t h e g a t e , i n c r e a s i n g C G S and C G D . The t r a n s v e r s e f i e l d p r o f i l e due t o V D S i n c o m b i n a t i o n w i t h t h e a l t e r i n g d e p l e t i o n boundary a c c e l e r a t e s m o b i l e charge i n t h e c h a n n e l from s o u r c e t o d r a i n moving ch a r g e from or t o t h e h o l d node depending on t h e magnitude o f v h o l d v s - v i n - A f t e r 25ps t h e down ramp p r o p a g a t e s down and r e f l e c t s from t h e u n t e r m i n a t e d gate end c a u s i n g f i e l d s t o p e n e t r a t e t h e a c t i v e l a y e r . The m a j o r i t y c a r r i e r s move down the p o t e n t i a l g r a d i e n t t o the s o u r c e and d r a i n , d e c r e a s i n g C G S and C G D and r e v e r s i n g the s o u r c e c u r r e n t of the p r e v i o u s s t a t e . The r a p i d d i s p l a c e m e n t o f charge from t h e c h a n n e l t o t h e s o u r c e and d r a i n a r e a s l i k e l y causes most of t h e o b s e r v e d v o l t a g e change which i s r e f e r r e d t o as "sample s t r o b e blow-by" by B a r t a and R o d e [ 1 . 2 ] . I d e a l l y the magnitude of t h e " s t r o b e f e e d t h r o u g h " t o the o u t p u t of t h e sample and h o l d would be n e g l i g i b l e . The bandwidth of t h e a m p l i f i e r s h o u l d be maximized f o r m i n i m i z a t i o n of t h e number of ISAB u n i t s [ 1 . 1 ] . Thus t h e s t r o b e f e e d t h r o u g h s h o u l d be m i n i m i z e d a t t h e s w i t c h . RSAG1_2 Pulse Gate End -0-2 F i g . 5.4 S i n g l e Gate D i s t r i b u t e d S i m u l a t i o n } 5.2 GUARD AND SAMPLING GATE BIASING CONSIDERATIONS 56 The o p e r a t i o n of the s w i t c h w i t h r e s p e c t t o sample and h o l d i s such t h a t , when the s w i t c h i s on, V D g t e n d s t o z e r o w h i l e b r i n g i n g t h e h o l d c a p a c i t a n c e t o a p o t e n t i a l near the s o u r c e p o t e n t i a l . When the s w i t c h i s o f f the s o u r c e i s f r e e t o f o l l o w e x c u r s i o n s which do not i n a d v e r t e n t l y b i a s t h e s w i t c h on w i t h t h e c h a r g e d h o l d c a p a c i t a n c e s u p p l y i n g a v o l t a g e t o the a m p l i f i e r i n p u t MESFET. The h o l d c h a rge l e a k a g e p a t h s i n c l u d e MIM or ID c a p a c i t o r l e a k a g e , s w i t c h shunt l e a k a g e , a m p l i f i e r i n p u t l e a k a g e and s u b s t r a t e shunt l e a k a g e . The a m p l i f i e r i n p u t b i a s s h o u l d be such t h a t t h e o u t p u t b i a s i s v e r y c l o s e so as t o e n a b l e c a s c a d e o p e r a t i o n f o r s e v e r a l s t a g e s . A m p l i f i e r i n p u t b i a s i s i n t h e o r d e r of 0.3V T, v a r y i n g w i t h the s p e c i f i c a m p l i f i e r component c h a r a c t e r i s t i c s . A m p l i f i e r g a i n and o u t p u t swing l i m i t t h e i n p u t swing such t h a t V ^ o i a s h o u l d v a r y by about 200mV about the symmetry b i a s p o i n t . The guard g a t e b i a s s h o u l d be such t h a t c h a r g i n g c u r r e n t i s maximized w i t h o u t c a u s i n g g a t e f o r w a r d c o n d u c t i o n , about 500 mV above t h e most n e g a t i v e i n p u t s i g n a l e x c u r s i o n . 5.3 HOLD CAPACITANCE CONSIDERATIONS The optimum magnitude of t h e h o l d c a p a c i t a n c e i s d e t e r m i n e d by t h e r a t e of c h a r g i n g f o r t h e a p e r t u r e a v a i l a b l e . The g u i d e l i n e a p e r t u r e i s t h e h i g h e s t p r i o r i t y a s p e c t of t h e d e s i g n . A m p l i f i e r i n p u t c a p a c i t a n c e i s m a i n l y C g S of t h e i n p u t MESFET p l u s a s m a l l p a r a s i t i c c o n t r i b u t i o n and as such 57 is a function of Vg S. Reduction of potential distortion can be accomplished by increasing the ratio of fixed capacitance to variable capacitance. Fixed capacitance is from two sources, parasitic or layout dependent and MIM or interdigitated structures. The estimated node capacitance for the Barta and Rode ISAB is 0.3pF of which half is MIM and the other a combination of parasitic and depletion layer. The amplifier input width is 50mn implying CgGg of about 60fF combined with the node side guard gate width of 100/im amounting to C Srjo~ 1 2OfF, with the node at zero volts. Parasitic capacitance originates with the layout separations, substrate thickness and dielectric constant. If the ISAB is mounted on a sheet of conducting epoxy at ground potential the surface metalizations form a MIM capacitor. Substrate thickness is about 450mn leading to an approximate capacitance per unit area of eGaAs/d=*25, 700f F/cm2. For a 100Mm 2 pad this amounts to about 2.6fF. This would increase for a thinned substrate design incorporating the entire DRFM acquisition unit including microstrip delay line. The rate of charging for a single gate switch at V D S is determined by switch characteristics and V G S. A multiple gate switch has a lower charging rate due to the added guard channels in series. Barta and Rode[1.2] claim that in a three gate switch "the outside gates serve a shielding function by minimizing the effects of sample strobe blow-by reflected back into the input source and coupled onto the output signal." 58 Comparative lumped element modeling of this configuration with equivalent input time constant single and dual gate configurations is shown in section 7 simulations. The switch slice parameters are accumulated in table 5.1. Figure 5.2 is the equivalent circuit of a triple gate switch slice connected to the amplifier input FET with a fixed capacitance(Cf). The distributed model of the switch incorporates the switch as a set of n slice elements connected to simulate the layout of figure 5.1 as demonstrated in figure 5.3 for n=3. Notts ICSrTT ID CS50 11) Rc (2) Rs (3) RH (4) TMJ (5) RSAG if OhM onus ones usee 1 6ate to Source Caoacitance i t Vgs=0 V 61 1 1 2 0.59. 144.2 1169.7 705.5 0.71 Contact Resistance S 1 1 2 0.59 0.0 705.5 705.5 0.71 62 1 : 2 0.59 IM . : 705.5 1169.7 0.71 3 Source resistance SI 1 2 2 1.17 144.2 1555.2 1091.0 2.86 S i 2 2 1.17 0.0 1091.C 1091.0 2.86 4 Drain resistance 62 1 2 2 1.17 144.2 1091.0 1555.2 2.86 J C T T t i u v . u ianne i L a n g i n / M i u f a l i g n v e i g t i i y TiiAu Selective laciint NESFETJ 31 1 1 2 1.17 144.2 3226.2 1542.0 2.36 S 1 ! 1.17 0.0 1542.0 1542.0 2.86 S2 1 1 2 1.17 144.2 1542.0 3228.2 2.B6 Mtl R1.261 RI 2S R 1.252 R2.2S1 R2.2S R2.2S2 S1.261 S1.2S S1.262 UNITS 0.5 0.5 0.5 1 1 1 1 1 1 ut S/D Sao 2 2 2 2 2 2 2 2 2 ue VTO .? -2 -2 -2 -2 -2 -2 -2 V VB! 1.23 1.23 1.23 1.23 1.23 1.23 1.23 1.23 1.23 V RE 4.97 4.97 4.97 1.49 1.49 1.49 0.13 0.128 0.128 onus ALPHA 2.J 2.3 2.3 2.3 2.3 2.3 2.3 2.3 2.3 SETA 3.055M5 3.055EK.3 3.055E-05 2.615E-05 2.615E-05 2.615E-05 2.6I5E-05 2.615E-05 2.615E-05 A/V-2 'JWDA 0.055 0.055 0.055 0.055 0.055 0.055 0.055 0.055 0.055 CSSO 0.586 0.586 •}.586 1.173 1.173 1.173 1.190 1.190 < 1.190 fF CSD 0.566 0.5B6 0.536 1.173 1.173 1.173 1.190 1.190 1.190 fF CDS 0.0791 0.0736 0.0714 0.096 0.0847 0.0791 0.096 0.0B47 0.0791 fF IS 2.07E-O5 2.V7E-05 2.07E-O5 4.13E-05 4.13E-05 4.13E-05 4.13E-05 4.13E-05 4.13E-05 A RS 1169.7 705.3 705.5 1555.2 1091.0 1091.0 3228.2 1542.0 1542.0 ohn RD 705.5 705.5 1169.7 1091.0 1091.0 1555.2 1542.0 1542.0 3228.2 ohm m 0.71 0.7: 0.71 . 2.86 2.86 2.86 2.86 2.96 2.86 os Table 5.1 MESFET Parameters for sampling switches. 6. AMPLIFIER LAYOUT The a m p l i f i e r e q u i v a l e n t c i r c u i t of f i g u r e 6.1 i s r e a l i z e d w i t h t h e l a y o u t of f i g u r e 6.2. The r e l a t i v e feedback MESFET w i d t h was t a k e n as 25% of BPU a f t e r Van T u y l [2.4] g i v i n g about 3dB g a i n . I n t h e l a y o u t BPU i s t h e MESFET most a f f e c t e d by gate m e t a l i z a t i o n r e s i s t a n c e , as i t i s not d r i v e n a t b o t h ends. F o r t h e SPICE t r a n s i e n t s i m u l a t i o n s R Q i s t a k e n as 1/3 the end t o end m e t a l i z a t i o n r e s i s t a n c e a f t e r W o l f [ 4 . 3 ] f o r an end d r i v e n g a t e and 1/2 of t h a t f o r b o t h ends d r i v e n . •*|rBPu BLPU rt y »> y »e u u GNO VSS F i g . 6.1 A m p l i f i e r E q u i v a l e n t C i r c u i t . 59 60 Fig. 6.2 Amplifier Layout The -3dB frequency of the amplifier is determined by pole interaction treated by Hornbuckle and Van Tuyl[1.7], Step response settling time is a more suitable performance measure for sampling. The input step of the simulations is a 0.1ps transition carried out about the amplifier symmetry bias point. The step amplitude is chosen to reflect the maximum excursions of the hold node with respect to keeping the amplifier output linear. AORT3_9012 DC Characteristics 3 -. 4 3 2 O -1 •2 I i 1 1 1 i—i 1 i i 1 1 -1.2 -1 -0.8 -0.6 -0.4 -0.2 O vm (v) . 6.3 A m p l i f i e r Open Loop DC C h a r a c t e r i s t i c s A0RT3_9012 Transient F i g . 6.4 AORT3_9012 Open Loop T r a n s i e n t AFRT3_9012 DC Characteristics VH (V) 6.5 90tim RSAG1_2 Amplifier DC Characteristics AFRT3_9012 Transient 2.3 > 0.5 -0.5 4 S (Tbn« 10E-10) Tim* (*) g. 6.6 90/xm RSAG1_2 Amplifier Step Response 63 AFRT3_9022 DC Characteristics F i g . 6.7 90<xm RSAG2_2 A m p l i f i e r DC C h a r a c t e r i s t i c s F i g . 6.8 90Mm RSAG2_2 A m p l i f i e r S t e p Response 64 AFST3_9012 DC C h a r a c t e r i s t i c s -1.2 -1 -0.8 -0.6 -0.4 -OJ 0 Vh (V) Fig. 6.9 90iim S11_2 Amplifier DC Characteristics AFST3_9012 T r a n s i e n t 3.3 _ 1.5 - > 1 - 0.5 - O -• -1-3 -i—i—i—i—i—r—i—i—i—i—i—i—I—i—i—i—r—i—i—i— 0 0.2 0.4. 0.6 0.8 1 1.2 1.4 1.6 1.8 2 (TVnw 10E-9) Hm« (•) Fig. 6.10 90mn SI1_2 Amplifier Step Response 65 The S c h o t t k y d i o d e s t a c k number and w i d t h were chosen t o m a i n t a i n about a 1 V per d i o d e v o l t a g e d r o p f o r a g i v e n s u p p l y v o l t a g e d i f f e r e n c e , s c a l e d w i t h V T , and t o t a l R p S t o ba l a n c e t h e o u t p u t and i n p u t v o l t a g e s . As th e i n p u t v o l t a g e swing i s b i a s e d near t h e c e n t e r of the i n p u t MESFET o p e r a t i n g c h a r a c t e r i s t i c the o u t p u t v o l t a g e must c o i n c i d e t o g i v e c a s c a d e c a p a b i l i t y . The a m p l i f i e r t r a n s i e n t and DC c h a r a c t e r i s t i c s a r e shown i n f i g u r e s 6.4 t h r o u g h 6.10 f o r the t i g h t e s t l i t h o g r a p h i c t o l e r a n c e s of the t h r e e major performance g r o u p s . The f a s t e s t s e t t l i n g t ime i s l e s s than 200ps f o r RSAG1_2 t e c h n o l o g y . A m p l i f i e r v a r i a t i o n s were g e n e r a t e d f o r 30 t o 120ixm maximum MESFET w i d t h range, w i t h 2, 3 and 4 d i o d e s t a c k s of bot h RD and TD typ e f o r the n i n e MESFET parameter s e t s . The r o l e of th e a m p l i f i e r i n t h i s p r o j e c t was t o demonstrate minimum s e t t l i n g t ime f o r the DRFM a p p l i c a t i o n , w h i l e p r o v i d i n g a s u i t a b l e a d j u n c t f o r t h e s w i t c h . V a r i a b l e h o l d c a p a c i t a n c e i n c r e a s e s w i t h i n p u t w i d t h , o u t p u t d r i v e d e c r e a s e s w i t h w i d t h and phase s h i f t d e g r a d a t i o n of t r a n s i e n t performance i n c r e a s e s w i t h w i d t h . The 67iim i n p u t w i d t h has a C a m p i n of about 20fF f o r RSAG1_N and 40fF f o r the o t h e r p r o c e s s e s a t the r e q u i r e d i n p u t b i a s . The c o m b i n a t i o n of guard g a t e c a p a c i t a n c e w i t h C a m p ^ n r e s u l t s i n the a p p r o x i m a t e minimum c a p a c i t a n c e f o r i n p u t t i m e c o n s t a n t c a l c u l a t i o n s f o r d u a l and t r i p l e g a t e s w i t c h e s . 7. ISAB DESIGN AND LAYOUTS 7.1 CONFIGURATIONS The p o s s i b l e c o n f i g u r a t i o n s i n c l u d e s i n g l e , d u a l and t r i p l e g a t e s w i t c h e s of v a r i o u s w i d t h s i n each of t h e n i n e MESFET v a r i a t i o n s , combined w i t h an a m p l i f i e r i n the same or o t h e r p r o c e s s v a r i a t i o n . A r e p r e s e n t a t i v e group of 28 ISAB c o n f i g u r a t i o n s were i n c l u d e d on t h e mask w i t h a s u b s e t of 21 s e p a r a t e s w i t c h e s and 12 a m p l i f i e r s ( r e : F i g . 1.3). Seven SI p r o c e s s ISABs a r e i n c l u d e d w i t h o u t s e p a r a t e d components, as on c h i p p r i o r i t y was g i v e n t o RSAG u n i t s i n terms of r e s e a r c h i n t e r e s t . The SI u n i t s encompass 140um c e n t e r t a p s i n g l e , d u a l and t r i p l e g a t e s w i t c h e s i n b o t h 2 F i g . 7.1 SI and RSAG ISAB l a y o u t 66 67 s Iterate**} m a- P F i g . 7.2 MIM ISAB l a y o u t and 3/xm s o u r c e / d r a i n gap v a r i a t i o n s w i t h 90um a m p l i f i e r s i n the same v a r i a t i o n p l u s one s i n g l e g a t e 4*xm gap ISAB. The ISAB l a y o u t on the l e f t of f i g u r e 7.1 i s t h e t r i p l e g a t e 2/im gap v e r s i o n , of which a f u l l page l a y o u t i s i n c l u d e d i n appendix B. The minimum i n p u t t i m e c o n s t a n t f o r a g i v e n s w i t c h i s o b t a i n e d by e l i m i n a t i n g a l l f i x e d h o l d c a p a c i t a n c e , as seen i n e q u a t i o n 7-1. c h o l d = c f i x e d + c a m p i n + c g u a r d + c s w i t c h + c p a r a s i t i c guai [7-1] 68 The s w i t c h c o n t r i b u t i o n i s a c o m b i n a t i o n of C D s a n d C G D assuming t h e h o l d node i s t h e s w i t c h d r a i n s i d e . As guard g a t e s a r e added t h e r e s u l t i n g d e c r e a s e of node c h a r g i n g c u r r e n t makes i n t e r d i g i t a t e d c a p a c i t o r s a more a t t r a c t i v e p r o c e s s o p t i o n due t o t h e p r o c e s s y i e l d c o n s i d e r a t i o n s of MIM s h o r t s . 7.2 ISAB SIMULATION RESULTS T a k i n g the t h e o r e t i c a l l y d e r i v e d SPICE model pa r a m e t e r s from t a b l e 4.1 a r e p r e s e n t a t i v e s e l e c t i o n of l a r g e s i g n a l s i m u l a t i o n s were p e r f o r m e d . These i n c l u d e s i m u l a t i o n s of e x p e c t e d p u l s e and t r a n s i e n t c o n d i t i o n s i n d i c a t i v e of i n t r i n s i c performance w i t h i d e a l i n p u t c o n d i t i o n s . The o v e r a l l performance of a c t u a l d e v i c e s w i l l depend on a c t u a l i n p u t s and a s s o c i a t e d p a r a s i t i c s as w e l l as the i n t r i n s i c p e rformance h i g h l i g h t e d h e r e . The SPICE MESFET model v e r s i o n used has f i x e d C Q D w i t h a v a l u e t h e same as C G S Q . More a c c u r a t e c a p a c i t a n c e m o d e l i n g can be done a t t h e expense of i n c r e a s e d s i m u l a t i o n t i m e . C i r c u i t p a rameters f o r t h e SPICE s o u r c e l i s t i n g s f o r the s i m u l a t i o n s a r e i n appendix D. F i g u r e s 7.3 t o 7.5 show t h e s i m u l a t e d open s w i t c h t r a c k i n g of the t h r e e t i g h t e s t t o l e r a n c e RSAG ISABs w i t h a 1GHz s i n e wave i n p u t . As t h e number of guard g a t e s a r e i n c r e a s e d f i x e d node c a p a c i t a n c e i s d e c r e a s e d t o compensate, however as can be seen i n f i g u r e s 7.3 t o 7.5 s i g n i f i c a n t h o l d node a t t e n u a t i o n and phase s h i f t o c c u r s . Fig. 7.3 RSAG1_2 Single Gate ISAB Tracking Fig. 7.4 RSAG1_2 Dual Gate ISAB Tracking 70 RI36R912T3 Tracking -OJ -| F i g . 7.5 RSAG1_2 T r i p l e Gate ISAB T r a c k i n g RI16R912T3 Time Constant T 1—1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 I OJ 0.4 O.S 0.8 1 1.2 1.4 1.8 1.8 (Hmm 10C-10) Tim* (•) W •*•*> input — F i g . 7.6 RSAG1_2 S i n g l e Gate Time C o n s t a n t RI26R912T3 Time Constant i — r - i — i i i—i— i— i— i—i—i—• i i 0.2 0.4 0.6 0.S 1 1.2 1-4 1.6 (1)nt« 10C-10) Tim* (•) -7^- W atop input Fig. 7 .7 RSAG1_2 Dual Gate Time Constant RI36R912T3 Time Constant -0.33-1 -0.85 A—i—i—r—i—i—i—i—r—i—i—r—T—I—i—i—i—i—i—i— 0 CJ. 0.4 0.6 03 1 1.2 1.4 1.6 13 2 (Tim** 10E-10) Tim* (•) RT atop kiput -j- Mold nod* Fig. 7.8 RSAG1_2 Triple Gate Time Constant 72 F i g u r e s 7.6 t o 7.8 use t h e same c i r c u i t model as f i g u r e s 7.3 t o 7.5 w i t h a 0.1ps s t e p i n p u t of t h e same magnitude. The i n p u t t i m e c o n s t a n t i n c r e a s e s w i t h t h e number of g a t e s from about 40ps f o r 90% s a m p l i n g e f f i c i e n c y w i t h a s i n g l e g a t e s w i t c h t o about 52ps and 71ps f o r d u a l and t r i p l e g a t e s w i t c h e s . F i g u r e 7.9 shows t h e s i m u l a t e d d i s t o r t i o n of an i d e a l 50S2 t r a n s m i s s i o n l i n e p u l s e on the gate pad due t o a s i n g l e g o l d bond w i r e and v a r i a b l e c a p a c i t a n c e of t h e g a t e . F i g u r e s 7.10 t h r o u g h 7.12 show t h e e f f e c t of guard g a t e s on p u l s e f e e d t h r o u g h a t both t h e RF i n p u t s i d e and h o l d node s i d e . The h o l d node v o l t a g e changes t o a more n e g a t i v e v a l u e on s w i t c h c l o s u r e due t o c h a n n e l m a j o r i t y c a r r i e r d i s t r i b u t i o n a c r o s s c a p a c i t a n c e s . I n i t i a l l y the s i n g l e g a t e s w i t c h o f Pulse Dis t o r t i o n Tim* (•} -j— Transmission In* —g- Cat* pad F i g . 7.9 Pad P u l s e D i s t o r t i o n 73 RI16R912T3 Feedthrough (Hm« IOC-11) v _ 1km (•) CotoPulM -j,- UT Pod Hold nod* Fig. 7.10 Single Gate Feedthrough RI26R912T3 Feedthrough 0.4 Fig. 7.11 Dual Gate Feedthrough 74 RI36R912T3 Feedthrough > -3 0 4 Cote "ukM -j- Hotd nod* F i g . 7.12 T r i p l e Gate F e e d t h r o u g h f i g u r e 7.10 i s open w i t h s o u r c e and d r a i n a t t h e same p o t e n t i a l as t h e 152fF f i x e d c a p a c i t o r . When t h e s w i t c h ramps c l o s e d i n 5ps b o t h s o u r c e and d r a i n r e c e i v e an i n j e c t i o n of m a j o r i t y c a r r i e r c a u s i n g a n e g a t i v e v o l t a g e s w i n g . The l a c k of a v a i l a b i l i t y of n e u t r a l i z i n g c h a r g e f o r the h o l d node produces a s t o r e d n e g a t i v e o f f s e t of about 0.4V i n v e r s e l y p r o p o r t i o n a l t o the node c a p a c i t a n c e . The RF i n p u t s i d e i s n e u t r a l i z e d r e t u r n i n g t o i t s o r i g i n a l p o t e n t i a l i n about 20ps. On s w i t c h o p e n i n g m a j o r i t y c a r r i e r s a r e p u l l e d i n t o t h e c h a n n e l l e a v i n g a temporary l a c k a t s o u r c e and d r a i n , i n c r e a s i n g v o l t a g e . The r e s u l t a n t t r a n s i e n t decays i n a p p r o x i m a t e l y t h e same time as f o r s w i t c h c l o s u r e , about 20ps. 75 The d u a l g a t e s w i t c h of f i g u r e 7.11 has a s i n g l e g u ard g a t e on t h e h o l d node s i d e w i t h a 39fF f i x e d c a p a c i t o r . The h o l d node s t o r e d n e g a t i v e o f f s e t of f i g u r e 7.11 i s reduced i n the p r e s e n c e of t h e guard g a t e t o about one h a l f t h e s i n g l e g a t e magnitude of f i g u r e 7.10. The p o s t s w i t c h o p e n i n g t r a n s i e n t i s about 100mV l a r g e r r e q u i r i n g a l o n g e r s e t t l i n g t i m e . The guard gate C G S 0 i s about 3 6 f F , and V G S i s 0.3 V a t the a m p l i f i e r symmetry p o i n t g i v i n g a C G S of about 41f F from e q u a t i o n 4-3. Thus the combined d i s t r i b u t e d c a p a c i t a n c e f o r t h e i n i t i a l phase of the d u a l g a t e s i m u l a t i o n i s about 1 1 6 f F + C s w ^ t c h + < - a m p i n a s compared t o 1 5 2 f F + C s w ^ t c j 1 + C a m p i n f o r the s i n g l e g a t e . As c h a r g e i s t r a n s f e r e d t o t h e h o l d node d u r i n g the s w i t c h down ramp guard g a t e C G S i n c r e a s e s r e s p o n d i n g t o the change i n p o t e n t i a l t o about 4 7 f F . The d i s p l a c e d charge can be c o n s i d e r e d t o be h e l d on two nodes, the s w i t c h g u a r d g a t e node and the h o l d node s e p a r a t e d by t h e guard g a t e c h a n n e l . The a p p r o x i m a t e s i m u l a t e d c a p a c i t a n c e of the s w i t c h g u a r d g a t e node i s C s w£tch + c-GSguard a n o - t h a t of t h e h o l d node c a m p i n + c f i x e d + c G D g u a r d - T h e charge h o l d i n g a b i l i t y of t h e v a r i o u s c a p a c i t a n c e s i s d i r e c t l y p r o p o r t i o n a l t o t h e v o l t a g e a c r o s s t h e c a p a c i t a n c e . When the s t r o b e down ramp l e v e l s o f f the s w i t c h gate i s a t -2.9V such t h a t about -2.1V i s a c r o s s c s w i t c h * c G S g u a r d a n d cGDguard h a v e a b o u t + 0 - 5 v o l t s a c r o s s them and C f i x e ( j and C a m p ^ n a r e about +0.8 V. The d i s t r i b u t e d c a p a c i t a n c e of t h e two nodes t h u s h o l d s l e s s c h a r g e than the s i n g l e node of t h e s i n g l e s w i t c h ISAB. The "blow-by" 76 d i s p l a c e m e n t charge i s the same however, t h u s some of the c h a n n e l charge i s b e i n g n e u t r a l i z e d by a n o t h e r s o u r c e of c a r r i e r s . The most o b v i o u s p a t h f o r t h e s e c a r r i e r s i s from the b i a s s u p p l y t h r o u g h the guard g a t e S c h o t t k y d i o d e . F i g u r e 7.13 shows t h e v o l t a g e a t t h e guard node between t h e s w i t c h and t h e gu a r d g a t e f o r a d u a l g a t e s w i t c h , w i t h t h e same t r a n s i e n t c o n d i t i o n s as f i g u r e 7.11. The guard node v o l t a g e drops s u d d e n l y i n re s p o n s e t o e l e c t r o n s b e i n g i n j e c t e d from the s w i t c h . The v o l t a g e from g a t e t o s o u r c e of the g u a r d gate r e a c h e s about 0.9 V, c a u s i n g e l e c t r o n s t o t u n n e l t h r o u g h the S c h o t t k y b a r r i e r . F i g u r e 7.14 shows the gua r d g a t e c u r r e n t i n c r e a s e i n t h e p o s i t i v e g o i n g p u l s e , c o r r e s p o n d i n g t o the s t r o b e down ramp. The n e g a t i v e g o i n g c u r r e n t p u l s e i s m a i n l y due t o c a p a c i t i v e c o u p l i n g , and as RI26R912T3 Guard Gate Source and Drai n 0.3 -, 1 0.2-I (Tbr iM 10E-11) Tim* (•) ^ guard nod* ^ hold nod* F i g . 7.13 Guard Gate Source and D r a i n V o l t a g e s 77 RI26R912T3 Guard Gate Current ( T W I M tOE-11) Tlm» (•) Fig. 7.14 Guard Gate Current such is missing the conduction effect. The triple gate switch of figure 7.12 exhibits a reduced RF pad transient due to i t s guard gate and a larger hold node swing than either the single or dual gate switch. The reason for the increased hold node swing is reduced hold node capacitance in an attempt to improve the input time constant. The hold node capacitance is thus mainly composed of guard gate and amplifier input depletion capacitance which varies with hold node voltage. Unfortunately the tr i p l e gate switch is both slower in terms of input time constant and as a result of minimal fixed capacitance at the hold node not as good in terms of hold node feedthrough. While the single gate switch is predictably the fastest in terms of input time constant the dual gate exhibits about 78 one h a l f t h e f e e d t h r o u g h , a t t h e a m p l i f i e r i n p u t b i a s v o l t a g e , w i t h a 30% t i m e c o n s t a n t i n c r e a s e . F i g u r e s 7.15 t o 7.20 show sampled t r a c k i n g c o n d i t i o n s s i m i l a r t o t h o s e of B a r t a and Rode[1.3] u s i n g a 36MHz s i n e wave i n p u t , however the s t r o b e p u l s e s a r e a t 1 r a t h e r than 2ns i n t e r v a l s as s u g g e s t e d by t h e r e s e a r c h s p o n s o r . The s t r o b e p u l s e r i s e t i me i s t a k e n as 20% of t h e s t r o b e "ON" w i d t h f o r a l l t h e s i m u l a t i o n s . F i g u r e 7.15 shows sampled t r a c k i n g i f t h e RF pad i n p u t b i a s i s a t the same l e v e l as t h e unsampled t r a c k i n g of f i g u r e 7.3. Due t o t h e s t o r e d n e g a t i v e o f f s e t a t t h e h o l d node a f t e r s w i t c h c l o s u r e t h e a m p l i f i e r i n p u t i s b i a s e d about 200mV below i t s symmetry t r a n s f e r p o i n t . T h i s can be c o r r e c t e d by c h a n g i n g t h e b i a s of t h e RF pad i n p u t by 200mV as seen i n f i g u r e 7.16 r e s u l t i n g i n a s y m m e t r i c a l a m p l i f i e r o u t p u t . F i g u r e 7.18 shows t h a t the s i n g l e g a t e ISAB s t i l l t r a c k s when o p e r a t e d below th e 90% s a m p l i n g e f f i c i e n c y a p e r t u r e . The s i m u l a t i o n r e s o l u t i o n of f i g u r e 7.18 i s 50ps and as such some of t h e h o l d node d e t a i l i s l o s t . I t s h o u l d be n o t e d t h a t the a m p l i f i e r a c t s as a low pass f i l t e r w i t h r e s p e c t t o h o l d node t r a n s i e n t s and as such t h e i r o u t p u t magnitude can be l i m i t e d w i t h m i n i m a l sample and h o l d s i g n a l d e g r a d a t i o n by c h o o s i n g the a m p l i f i e r f r e q u e n c y r esponse a p p r o p r i a t e l y . F i g u r e 7.19 shows t r i p l e g a t e t r a c k i n g w i t h 300ps p u l s e s . S i g n a l d i v e r g e n c e problems were e n c o u n t e r e d , where h o l d node v o l t a g e would c o n s i s t e n t l y r i s e when u s i n g 79 F i g . 7.15 RI16R912T3 150ps T r a c k i n g , 0.6 V B i a s Fig. 7.16 RI16R912T3 150ps Tracking, 0.4 V Bias Fig. 7.17 RI16R912T3 75ps Tracking 82 I I I I I I I I I I I I A F i g . 7.18 RI16R912T3 25ps T r a c k i n g 83 F i g . 7.19 RI36R912T3 300ps T r a c k i n g F i g . 7.20 RI26R912T3 50ps T r a c k i n g 85 na r r o w e r p u l s e s . F i g u r e 7.20 shows d u a l g a t e t r a c k i n g a t 50ps, c l o s e t o t h e 90% s a m p l i n g e f f i c i e n c y i n p u t t i m e c o n s t a n t . B o t h f i g u r e s 7.19 and 7.20 e x h i b i t f e e d t h r o u g h c o m p r e s s i o n on t h e n e g a t i v e swing of t h e i n p u t s i n e wave and a s p r e a d i n g e f f e c t on t h e p o s i t i v e g o i n g h a l f c y c l e . T h i s e f f e c t i s not seen on t h e s i n g l e g a t e t r a c k i n g s i m u l a t i o n s of f i g u r e s 7.16 t o 7.18. The p r o b a b l e cause i s h o l d node s i d e g u ard g a t e b i a s w i t h r e s p e c t t o the h o l d node v o l t a g e . The guard g a t e v o l t a g e i s f i x e d such t h a t any d e p l e t i o n r e g i o n v a r i a t i o n o r gate c o n d u c t i o n i s c a u s e d by c h a n g i n g s o u r c e o r d r a i n p o t e n t i a l s . The d e p l e t i o n r e g i o n c a p a c i t a n c e w i l l d e c r e a s e as t h e s o u r c e / d r a i n p o t e n t i a l s i n c r e a s e and v i c e v e r s a . The amount of c h a r g e i s b e i n g e x p e l l e d from the s w i t c h by t h e a c t i o n of t h e s t r o b e i s r e l a t i v e l y c o n s t a n t . G r e a t e r c a p a c i t a n c e i s a v a i l a b l e a t t h e h o l d node w i t h more n e g a t i v e guard g a t e s o u r c e / d r a i n v o l t a g e s t h u s the s t o r e d n e g a t i v e o f f s e t i s l e s s , however o n l y s l i g h t change would be due t o t h i s as t h e c a p a c i t a n c e change i s o n l y a few f F . The n e u t r a l i z i n g c h a r g e i n j e c t e d by the h o l d s i d e guard g a t e w i l l depend on t h e i n i t i a l b i a s of the h o l d node as t h i s w i l l d e t e r m i n e t h e p o s i t i o n of t h e n e g a t i v e t r a n s i e n t on the v o l t a g e a x i s of f i g u r e 7.13. The more n e g a t i v e the peak the g r e a t e r t h e amount of n e u t r a l i z i n g c h a r ge p a s s i n g t h r o u g h t h e g u ard g a t e S c h o t t k y d i o d e under f o r w a r d b i a s e d c o n d i t i o n s . Thus f e e d t h r o u g h i s l e s s w i t h l o w e r h o l d node v o l t a g e . 86 The amplifier bandwidth is instrumental in determining the peak feedthrough voltage. Comparison of devices should thus be done on the basis of similar amplifier bandwidth. The amplifier bandwidth of Barta and Rode[1.3] is in the order of 1GHz whereas the RSAG1_2 amplifier bandwidth is in the order of 3GHz. The simulations were done with fixed C Q D at C G g Q which is a reasonable approximation for V Q D near 0 V and low V D S. More accurate capacitance simulation would be very unlikely to reduce the 200 to 800mV feedthrough transients of the simulations an order of magnitude to compare directly with the experimental 35mV feedthrough of Barta and Rode. The discrepancy would seem to be with the pulse parameters of the experimental setup compared to ideal pulses combined with transient response of the amplifier and measuring system compared to the simulated version. 8. PROCESS MONITORS AND MEASURED RESULTS The e a r l y v e r i f i c a t i o n of d e v i c e c h a r a c t e r i s t i c s enhances f a b r i c a t i o n t r o u b l e s h o o t i n g . T e s t probes can be u s e d , as soon as AuGe ohmics a r e p r e s e n t , t o v e r i f y i m p l a n t a c t i v a t i o n and i d e a l i t y f a c t o r . At t h e same time MESFET DC c h a r a c t e r i s t i c s and m e t a l sheet r e s i s t a n c e can be c h e c k e d . 8 .1 ISOLATION MONITORS The i s o l a t i o n m o n i t o r s ( a t c o o r d i n a t e s G 1L, G 1R ,G 10, H 10 i n f i g u r e 1.3) a r e ohmic pads on combined Nminus and N p l u s i m p l a n t s s e p a r a t e d by a gap t o t e s t t h e n o n a c t i v a t e d s u b s t r a t e f o r r e t e n t i o n o f t h e s e m i - i n s u l a t i n g sheet r e s i s t a n c e of about 3-10 * O / n i n b o t h c r y s t a l d i r e c t i o n s w i t h r e s p e c t t o t h e major f l a t . S h o u l d t h i s i s o l a t i o n be l e s s f o r some re a s o n i t i s p o s s i b l e t o i n c o r p o r a t e an i s o l a t i o n i m p l a n t [ 8 . 1 ] . 8.2 TLMS The t h r e e t r a n s m i s s i o n l i n e s (L 5T, L 5B, L 10) measure th e c o n t a c t r e s i s t a n c e of the AuGe ohmic pads t o the t h r e e p o s s i b l e i m p l a n t c o m b i n a t i o n s f o r c a l i b r a t i o n of p r o c e s s a n n e a l c h a r a c t e r i s t i c s . The pad gaps a r e measured by SEM and t h e d a t a a n a l y z e d by use of the t r a n s m i s s i o n l i n e model[8.2] f o r a c c u r a t e r e s u l t s . 87 88 8.3 POWER MESFET The gate of an open drain power MESFET should be driven with the last amplifier output. A power MESFET requires airbridges for the interdigitated gate architecture. This architecture could be expanded to a dual gate configuration for output sampling to a time domain multiplexed transmission line. A single gate version power MESFET has been included on the mask for fabrication evaluation. [8 . 3 ] . 8.4 TIW SHEET RESISTANCE The stepped resistor pattern used to determine TiW sheet resistance is shown in figure 8.2. The actual segment widths can be measured by SEM and the r e s i s t i v i t y calculated after [2.2]. Fig. 8.1 Power MESFET Gate Strip Layout 89 Fig. 8.2 TiW Stepped Resistor Layout \ 8.5 THREE AMPLIFIER OSCILLATOR Airbridges were used to construct a three amplifier ring oscillator to verify simulation. The RSAG1_3 MESFET was used as a base unit to increase the probability of a l l three amplifiers working. 8.6 PEAKING INDUCTOR The amplifier frequency response can be improved by adding a pole with a peaking inductor in series between the input and output stages.[1.8] r F i g . 8.4 Amplifier Peaking Inductor 91 8.7 SELECTIVE IMPLANT FABRICATION RUN RESULTS 8.7.1 ISOLATION The isolation monitors are two 150*im square pads on Nplus GaAs separated by a 15/um gap of SI GaAs. Figure 8.5 shows the current and resistance plots for a low voltage scan of the monitor on test chip 8. Considering the positive voltage side a diode characteristic appears with a series resistance in the order of 15k£2 implying a sheet resistance of 150kJ2/n. Figure 8.6 from chip 5 shows about 5MJJ series resistance corresponding to about 50MR/n of isolation which is an improvement over chip 8 however does not match the expected semi-insulating value of 300MJ2/n. Switch "OFF" isolation and hold mode I R (UA) (n ) 145.9 MARKER (- .6000V 1 . i . -2.B65UA . 209E+03 ) 232.0 E+03 14.59 /div .0000 23. 15 /div .4476 -2.000 0 .4000/div 2.000 V ( V) Fig. 8.5 Isolation monitor chip 8 92 MARKER {- .BOOOV . - 7 . 5 1 7 n A . 1Q6E+Q6 ) V .4000/div ( V) F i g . 8.6 I s o l a t i o n m o n i t o r c h i p 5 l e a k a g e a r e the two most c r i t i c a l p erformance a s p e c t s of i s o l a t i o n . 8.7.2 DOPING AND MOBILITY PROFILES U s i n g the f a t FET a t g r i d p o s i t i o n K-1 of f i g u r e 1.3 on t e s t c h i p 8 the d o p i n g and m o b i l i t y p r o f i l e s of f i g u r e s 8.7 and 8.8 a r e o b t a i n e d . The Nminus i m p l a n t f o r t h i s run was a dose of 3 • 1 0 1 2 i o n s / c m 2 a t 125keV. The peak d e p t h i s about 103nm w i t h an a c t i v a t e d dose of 2.6-10<|2 i o n s / c m 2 or about 87%. T h i s i s h i g h e r than the d e s i g n s i m u l a t i o n c a l c u l a t i o n a ssumption of 60% a c t i v a t i o n r e p r e s e n t i n g a 45% i n c r e a s e f o r the SI p r o c e s s , however a n n e a l i n g i s performed a t a lower t e m p e r a t u r e f o r the RSAG p r o c e s s which may r e s u l t i n F i g . 8.7 SI d o p i n g p r o f i l e . 3831 tn \ > \ (M < £ u L L 3112 F- r 2334 P r 1556 p F ~1 H J j j -i M 778. 1 h § t t a t- -779.1 .2 .3 DEPTH (MICRONS) .5 F i g . 8.8 SI m o b i l i t y p r o f i l e . 94 lower activation. Mobility is close to the assumed value of 3500 cm2/V-s. 8.7.3 SI MESFET CHARACTERISTICS The measured I-V characteristics of figures 8.9 and 8.10 are 236um width ir-gate MESFETs for which industry specifications are available. Three versions of this device are present on each chip, corresponding to source/drain gaps of 2, 3 and 4um. The published device IO (mA) C U R S O R 31.13 3.113 / d i v .0001 .0000 3.2000V , 31.10mA . / I 1 fy r Y D S .3500/div ( V) 3.500 GRA3 1 / G R A D ••• X i n t e r c e p t ' Y i n t e r c e p t ! LINE1 12.BE-03 78.3E+00 12.0E-03 : -154E-06 • i LINE2. 1 5 . 9 E - 0 6 ; 52 . 9E-rQ3, -1 .95E+03 , 3 1 . 0 E - 0 3 \ Fig. 8.9 SF_236_1_4 7r-gate I-V characteristics, VT^-2.7V, l D S S " 3 0 m A 95 ID (RIA) 71.70 MARKER 7.168 /div .0228 .0000 VDS ,3000/div ( V) 3.000 F i g . 8.10 SF_236__1_2 jr-gate I-V c h a r a c t e r i s t i c s , VT=*-3.7V, I D S S a ' 7 0 m A s p e c i f i c a t i o n s of manufacturers have a V T and I Q S S tolerance t y p i c a l l y ranging from -4 to -2V and 30 to 70mA respectively. The measured c h a r a c t e r i s t i c s of our S I devices are in t h i s range. 9 . CONCLUSION Sample and h o l d c y c l e s , w i t h i d e a l s w i t c h s t r o b e p u l s e s , i n d i c a t e a s i n g l e ga te 0.5/im MESFET s w i t c h i n t e g r a t e d s a m p l i n g a m p l i f i e r b l o c k w i l l have the b e s t i n p u t t ime c o n s t a n t , and l i k e l y be the o n l y u n i t , a t t h i s l e v e l of l i t h o g r a p h y , c a p a b l e of s u c c e s s f u l o p e r a t i o n w i t h 25ps p u l s e s . The mechanisms by wh i ch MESFET s w i t c h g u a r d g a t e s a f f e c t sample and h o l d s w i t c h o p e r a t i o n have been d e m o n s t r a t e d by s i m u l a t i o n . S t r o b e p u l s e f e e d t h r o u g h i s r e d u c e d by momentary f o r w a r d c o n d u c t i o n of the gua rd g a t e , a l l o w i n g d i s p l a c e d c a r r i e r s t o t u n n e l out of t he s w i t c h c h a n n e l . The number of c a r r i e r s i n v o l v e d i n t he t u n n e l i n g a c t i o n i s gua rd ga te b i a s and s i g n a l l e v e l s e n s i t i v e c a u s i n g some d i s t o r t i o n of the ou tpu t s i g n a l . The i n p u t t ime c o n s t a n t i n c r e a s e s , due t o the e x t r a guard c h a n n e l s i n s e r i e s , i s i n the o r d e r of 30 t o 40% when u s i n g a r e d u c t i o n of h o l d node c a p a c i t a n c e . The a p p l i c a b i l i t y of the GaAs RSAG p r o c e s s t o sample and h o l d s w i t c h d e s i g n has been v e r i f i e d by a m u l t i p l e ga te s l i c e s i m u l a t i o n , i n d i c a t i n g i n the o r d e r of 5ps ga te c e n t e r t a p t o g a t e end d e l a y f o r a 30Mm w i d t h t - g a t e . 96 REFERENCES 1.1 L. J . Conway and S. L. Bouchard, "The S a m p l i n g A m p l i f i e r " , DREO REPORT NO. 863, (1982). 1.2 P.H. S a u l , "A GaAs MESFET Sample and H o l d S w i t c h , " IEEE JSSC, V o l . 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Kniepkamp, " S o l i d - S t a t e E l e c t r o n i c s , V o l . 23, 9, (1 9 8 0 ) . 3.3 H.H. B e r g e r , "Models f o r C o n t a c t s t o P l a n a r D e v i c e s , " S o l i d - S t a t e E l e c t r o n i c s , V o l . 15, 145-158, ( 1 9 7 2 ) . 3.4 P. Townsley P r o c e s s E n g i n e e r , U.B.C. E l e c t r i c a l E n g i n e e r i n g S o l i d - S t a t e Lab, v e r b a l communication. 3.5 P.K. Vasudev, B.L. M a t t e s , E. P i e t r a s and R.H. Bube, "Excess C a p a c i t a n c e and N o n - I d e a l S c h o t t k y B a r r i e r s on GaAs," S o l i d - S t a t e E l e c t r o n i c s , V o l . 19, 557-559, (1976) 4.1 P r e c i s i o n Photomask I n c . v e r b a l communication. 4.2 K a r l Suss mask a l i g n e r manual. 4.3 W. D u r t l e r , P. Townsley and L. Young, "High Speed G a l l i u m A r s e n i d e S w i t c h e s , " P r o g r e s s R e p o r t t o 31 May 1985 s u b m i t t e d t o DREO. 4.4 P. Wo l f , "Microwave P r o p e r t i e s of S c h o t t k y - B a r r i e r 99 F i e l d - E f f e c t T r a n s i s t o r s , " IBM J o u r n a l Res. & Dev., V o l . 14, 125-141, ( 1 9 7 0 ) . 4.5 P.H. Ladbrooke, "Some E f f e c t s of Wave P r o p a g a t i o n i n t h e Gate of a Microwave MESFET," E l e c t r o n i c s L e t t e r s , V o l . 14, No. 1, 21-22, (1978) 4.6 Y. Wang and M. Bahrami, " D i s t r i b u t e d E f f e c t i n GaAs MESFET," S o l i d - S t a t e E l e c t r o n i c s , V o l . 22, 1005-1009, (1979) 4.7 R.L. Kuvas, " E q u i v a l e n t C i r c u i t Model of FET I n c l u d i n g D i s t r i b u t e d Gate E f f e c t s , IEEE T r a n s . ED, ED-27, No. 6, 1193-1195, (1980) 4.8 W. H e i n r i c h and H.L. H a r t n a g e l , "Wave P r o p a g a t i o n on MESFET E l e c t r o d e s and I t s I n f l u e n c e on T r a n s i s t o r G a i n , " IEEE MTT, MTT-35, No. 1, 1-8, (1987). 4.9 L. W. N a g e l , "SPICE 2: A computer program t o s i m u l a t e s e m i c o n d u c t o r c i r c u i t s , " E l e c t r o n i c s R e s e a r c h Lab, C o l . Eng., U n i v e r s i t y of C a l i f o r n i a , B e r k e l e y , Memo. ERL-M520 (1 9 7 5 ) . 4.10 W.R. C u r t i c e , "A MESFET Model f o r Use i n t h e D e s i g n of GaAs I n t e g r a t e d C i r c u i t s , " IEEE T r a n s . MTT, MTT-28, No. 5, 448 (1980). 4.11 S.E. Sussman-Fort, S. Narasimhan and K. Mayaram, "A Complete GaAs MESFET Computer Model f o r SPICE," IEEE T r a n s . MTT, MTT-32, No. 4, 471 ( 1 9 8 4 ) . 4.12 W.R. C u r t i c e and Yong-Hoon Yun, "A Temperature Model f o r the GaAs MESFET," IEEE T r a n s . ED, ED-28, No. 8, 954, (19 8 1 ) . 4.13 W.R. C u r t i c e and R.L. Camisa, " S e l f - C o n s i s t e n t GaAs FET Models f o r A m p l i f i e r D e s i g n and D e v i c e D i a g n o s t i c s , " I E E E T r a n s . MTT, MTT-32, No. 12, 1573 ( 1 9 8 4 ) . 4.14 W.R. C u r t i c e and M. E t t e n b e r g , "A N o n l i n e a r GaAs FET Model f o r Use i n t h e D e s i g n of Output C i r c u i t s f o r Power A m p l i f i e r s , " IEEE T r a n s . MTT, MTT-33, No. 12, 1383 ( 1 9 8 5 ) . 4.15 P h i l i p L. Hower and N. George B e c h t e l , " C u r r e n t S a t u r a t i o n and S m a l l - S i g n a l C h a r a c t e r i s t i c s of GaAs F i e l d - E f f e c t T r a n s i s t o r s , " IEEE T r a n s . ED, ED-20, No. 3, 100 (1973) . 4.16 S.E. Sussman-Fort, J.C. Hantgan and F.L. Huang, "A SPICE Model f o r Enhancement and D e p l e t i o n Mode GaAs FETs," IEEE MTT, MTT-34, No. 11, 1115-1119, (1986). 4.17 I.M. A b d e l - M o t a l e b , W.C. R u t h e r f o r d and L. Young, "GaAs I n v e r t e d Common D r a i n L o g i c ( I C D L ) and I t s Performance Compared w i t h Other GaAs L o g i c F a m i l i e s , " t o be p u b l i s h e d S o l i d - S t a t e E l e c t r o n i c s , ( 1 9 8 7 ) . 4. 18 J . M i c h a e l G o l i o , John R. Hauser, and P e t e r A. B l a k e y , "A L a r g e - S i g n a l GaAs MESFET Model Implemented on SPICE," IEEE C i r c u i t s and D e v i c e s Magazine, 21-30, S e p t . (1985). 4.19 R.L. Van T u y l and C.A. L i e c h t i "High-Speed I n t e g r a t e d L o g i c w i t h GaAs MESFET's," IEEE JSSC, V o l . 9, No. 5, (1974) . 4.20 Tzu-Hung Chen and M i c h a e l S. Shur, " A n a l y t i c a l Models of I o n - I m p l a n t e d GaAs FET's," IEEE T r a n s . ED, ED-32, No. 1, 18-28, (1985) 4.21 S. Ch a u d h u r i and D.C. Look, " E f f e c t of the V e l o c i t y - F i e l d Peak on I-V C h a r a c t e r i s t i c s of GaAs FETs," S o l i d - S t a t e E l e c t r o n i c s , V o l . 26, No. 8, 811-814, (1983) 5.1 J.V. F a r i c e l l i , J . F r e y and J.P. K r u s i u s , " P h y s i c a l B a s i s of S h o r t Channel MESFET O p e r a t i o n I I : T r a n s i e n t B e h a v i o r , " IEEE T r a n s . ED, ED-29, No. 3, 377-388, (1982) 5.2 F.A. Buot, " E f f e c t s of V e l o c i t y Overshoot on Performance of GaAs D e v i c e s , w i t h D e s i g n I n f o r m a t i o n , " S o l i d - S t a t e E l e c t r o n i c s , V o l . 26, No. 7, 617-632, (1983) 6.1 D. B. E s t r e i c h , "A M o n o l i t h i c Wide-Band GaAs IC A m p l i f i e r , " IEEE JSSC, SC-17, 1166-1173, (1982). 8.1 D.C. D'Avanzo, " P r o t o n I s o l a t i o n f o r GaAs MESFETs," IEEE T r a n s . MTT, V o l . MTT-30, No. 7, (1982). 8.2 H.H. B e r g e r , "Models f o r C o n t a c t s t o P l a n a r D e v i c e s , " S o l i d - S t a t e E l e c t r o n i c s , V o l . 15, 145-158, (1972) 8.3 C. A. L i e c h t i , "Performance of Dual-Gate GaAs MESFET's as G a i n - C o n t r o l l e d Low-Noise A m p l i f i e r s and High-Speed M o d u l a t o r s , " IEEE T r a n s . MTT, MTT-23, No. 6, (1 9 7 5 ) . 101 8.4 Y. Ikawa, W.E. E i s e n s t a d t and R.W. D u t t o n , " M o d e l i n g of High-Speed, L a r g e - S i g n a l T r a n s i s t o r S w i t c h i n g T r a n s i e n t s from s-Parameter Measurements," IEEE JSSC, SC-17, No. 2, ( 1 9 8 2 ) . 10. APPENDIX A -ICDL SIMULATIONS 10.1 DIGITAL INTEGRATED CIRCUIT SIMULATION OVERVIEW I n v e r t e d common d r a i n l o g i c ( I C D L ) , was modeled c o m p a r a t i v e l y t o o t h e r GaAs MESFET l o g i c s . ICDL i s a new l o g i c c i r c u i t c o n f i g u r a t i o n d e v e l o p e d by A b d e l - M o t a l e b [ 4 . 1 7 ] i n w hich t h e l o g i c f u n c t i o n s a r e r e a l i z e d u s i n g the p u l l u p r a t h e r t h a n the pulldowm t r a n s i s t o r s w hich a r e n o r m a l l y used. D e p l e t i o n ("normally on") t r a n s i s t o r s a r e employed. The b a s i c s w i t c h i n g modes and t h e advantages and problems a r e d i s c u s s e d . S i m u l a t i o n s were done u s i n g b o t h t h e JFET and the Sussman-Fort MESFET models i n SPICE. E x p e r i m e n t a l r e s u l t s were f i r s t s i m u l a t e d u s i n g p a r a m e t r i c d a t a o b t a i n e d from measurements. In o r d e r t o attempt t o compare performance w i t h some w e l l e s t a b l i s h e d l o g i c a p p r o a c h e s , t h e s e were s i m u l a t e d u s i n g t h e same p a r a m e t r i c d a t a f o r a l l t h e l o g i c s . D e p l e t i o n t r a n s i s t o r s (which conduct f o r Vgg = 0) were used i n t h e f i r s t GaAs l o g i c c i r c u i t s because of t h e problems of f a b r i c a t i n g enhancement t y p e d e v i c e s w i t h s u f f i c i e n t l y c o n t r o l l e d t h r e s h o l d v o l t a g e s and low enough s e r i e s r e s i s t a n c e s ( R s and R D ) . In the BFL ( b u f f e r e d FET l o g i c ) a p p r o a c h , l o g i c f u n c t i o n s a r e a c h i e v e d , as shown i n F i g . 1 0 . 1 ( a ) , u s i n g c o m b i n a t i o n s of p u l l d o w n d e p l e t i o n t r a n s i s t o r s . T h i s i s t h e same, f o r example, as i n s i l i c o n MOSFET DCFL ( d i r e c t c o u p l e d FET l o g i c ) w h i c h uses enhancement d e v i c e s ( w h i c h a r e OFF f o r V Q S = 0 ) , e x c e p t t h a t 102 103 A F i g . 10.1 GaAs MESFET l o g i c . a) BFL ( b u f f e r e d FET l o g i c ) [1] - i - b) SDFL ( S c h o t t k y d i o d e FET l o g i c ) [ 2 ] c) DCFL ( d i r e c t c o u p l e d FET l o g i c ) [ 3 ] the o u t p u t must be l e v e l - s h i f t e d b e f o r e p r e s e n t a t i o n t o the next s t a g e , s i n c e a n e g a t i v e g a t e v o l t a g e ( w i t h r e s p e c t t o the s o u r c e ) i s r e q u i r e d t o t u r n o f f the d e p l e t i o n p u l l d o w n t r a n s i s t o r s . The l e v e l s h i f t i n g i s a c h i e v e d u s i n g S c h o t t k y d i o d e s . I n SDFL ( S c h o t t k y d i o d e FET l o g i c , F i g . 10.1(b)) the i n p u t s a r e combined u s i n g d i o d e s . E v e n t u a l l y , i t i s commonly b e l i e v e d , VLSI u s i n g GaAs w i l l be a c h i e v e d by u s i n g enhancement p u l l d o w n d e v i c e s [3] 1 104 and DCFL ( F i g . 1 0 . 1 ( c ) ) . The r e q u i r e d t h r e s h o l d v o l t a g e and low s e r i e s r e s i s t a n c e s may be o b t a i n e d u s i n g a s e l f - a l i g n e d g a t e t e c h n o l o g y [4-8] (once t h e i o n i m p l a n t a t i o n and a c t i v a t i o n p r o c e s s i s b e t t e r c o n t r o l l e d ) or e l s e some form of e t c h e d r e c e s s e d g a t e [ 9 ] , F o r t h e p r e s e n t we r e s t r i c t o u r s e l v e s , however, t o d e p l e t i o n t y p e t r a n s i s t o r s t o form the l o g i c and c o n s i d e r what advantages (or o t h e r w i s e ) may be o b t a i n e d by, so t o speak, t u r n i n g t h e l o g i c u p s i d e down by u s i n g t h e p u l l u p t r a n s i s t o r s t o form t h e l o g i c w i t h p u l l d o w n t r a n s i s t o r s a c t i n g as l o a d s . The i d e a of d o i n g t h i s seems an o b v i o u s one, but t h e r e i s s u r p r i s i n g l y l i t t l e p r e v i o u s c o n s i d e r a t i o n of i t i n t h e l i t e r a t u r e . Of what we c o u l d f i n d , t h e most s i g n i f i c a n t was t h e work of N u z i l l a t e t a l . [ 8 , 9 ] . 105 10.2 ICDL BASIC CIRCUITS The b a s i c g a t e s f o r ICDL [10] a r e assembled i n F i g . 10.2 and a r e f i r s t b r i e f l y l i s t e d b e f o r e d i s c u s s i o n i n l a t e r s e c t i o n s . The f i r s t ( F i g . 10.2(a) i s a n o n - i n v e r t i n g b u f f e r . T h i s b u f f e r was proposed p r e v i o u s l y by H a r t g r i n g e t a l . [11] f o r use i n c o n n e c t i o n w i t h dynamic s i l i c o n MESFET l o g i c . An i n v e r t e r i s needed and r e q u i r e s a second power s u p p l y V s s f o r l e v e l s h i f t i n g between s t a g e s . The i n v e r t e r c o n s i d e r e d , F i g . 1 0.2(b), d i f f e r s from t h e SDFL i n v e r t e r , F i g . 1 0 . 1 ( c ) , i n u s i n g an i o n i m p l a n t e d , n o n - v e l o c i t y s a t u r a t i n g , r e s i s t o r i n p l a c e of d i o d e s f o r l e v e l s h i f t i n g . The b u f f e r e d form of the i n v e r t e r , w i t h h i g h i n p u t impedance, i s a c t u a l l y t h e v e r s i o n most needed, and t h i s i s shown i n F i g . 1 0 . 2 ( c ) . The AND ga t e i s i n F i g . 10.2(d) and t h e OR g a t e i n F i g . 1 0 . 2 ( e ) , w i t h p o s s i b l e complex ga t e c o n f i g u r a t i o n s i n F i g . 1 0 . 2 ( f ) and ( g ) . A s i m i l a r i n v e r t e d OR ga t e was p r e v i o u s l y l i s t e d by N u z i l l a t e t a l . i n c o n n e c t i o n w i t h t h e i r q u a s i - n o r m a l l y - o f f l o g i c . Our l o g i c g a t e d i f f e r s by not h a v i n g a d i o d e between the p u l l u p t r a n s i s t o r s and t h e p u l l d o w n l o a d and a l s o by u s i n g a t r a n s i s t o r i n s t e a d of a r e s i s t i v e l o a d . A l s o N u z i l l a t e t a l . were s p e c i f i c a l l y s t u d y i n g q u a s i - n o r m a l l y - o f f d e v i c e s w i t h s m a l l t h r e s h o l d v o l t a g e s ( e i t h e r p o s i t i v e o r n e g a t i v e ) whereas we a r e c o n s i d e r i n g d e p l e t i o n t r a n s i s t o r s . W i t h t h i s c o n s t r a i n t N u z i l l a t e t a l . were a b l e t o r e q u i r e o n l y one p o s i t i v e s u p p l y . In ICDL a s u p p l y r a i l i s n e c e s s a r y t o accommodate medium t o l a r g e n e g a t i v e t h r e s h o l d v o l t a g e s . ICDL d i f f e r s from t h e SDFL Fig. 10.2 ICDL configurations: a)buffer, b)inverter, c)buffered inverter, d) AND, e)OR. f)F = H-F2 = (K+W) • (C+D) g)F = (A+B)•(C+D) 1 0 7 c o n f i g u r a t i o n not o n l y i n the use of a r e s i s t o r as v o l t a g e t r a n s l a t o r , but i n the use of t h e i n v e r t e d l o g i c as i n p u t b u f f e r . S i m i l a r l y ICDL d i f f e r s from the BFL c o n f i g u r a t i o n by removing the v o l t a g e t r a n s l a t i o n mechanism from the output p a t h . 10.3 BUFFER CIRCUIT Load l i n e p l o t s f o r the b u f f e r a r e g i v e n i n F i g . 10.3(a) t o show how the l o g i c l e v e l s a r e o b t a i n e d . The I D s v s V D S c h a r a c t e r i s t i c s a r e here p l o t t e d f o r c o n s t a n t a) b) F i g . 1 0 . 3 I n v e r t e d b u f f e r l o a d l i n e w i t h V D D = 3 V , V S S = 0 V , V Q D = 0 and - 2 . 5 V f o r the s w i t c h i n g t r a n s i s t o r c o r r e s p o n d i n g t o a h i g h and low l o g i c i n p u t , w i t h measured v s . model JFET and MESFET c h a r a c t e r i s t i c s i n (b) f o r (M-|) and (J-|) i n ( a ) . a) MESFET Model (Mi,) , JFET Model ( J ^ where V T • - 1 . 3 7 V and MESFET Model (M,) where V T = - 0 . 5 V b) Comparison of the J F E T ( J ) and MESFET(M) models v s . e x p e r i m e n t a l ( • ) d a t a : I D v s . V D S f o r V G S » - 0 . 5 and O . O V 108 V Dg instead of the usual constant V Gg needed for conventional FET logic. Using the common approximation for I D S below saturation I D s = 2/}( ( V G S - V T ) V D S - V D S 2 / 2 ) we can U S E V G S = V D S + V G D t 0 o ° t a i n t n e form we need I D S = 2^((V G D - V T ) V D S + V D S 2 / 2 ) . Here I D S > 0 i f V G D - Vm + V D S / 2 > 0. Above saturation, instead of the usual * D S = ^ ( V G S " VT^ 2 w e obtain I D S = 0 ( V D S + V Q D - V T ) 2 . For a high input (ie small V G D ) V D S for the switching transistor is small so that the output is high. For a low input ( V G D large and negative) V Dg is large so that the output is low. The load line plotted on these drain current characteristics for constant V G D is the pulldown depletion transistor characteristic for i t s V G S = 0. In Fig. 10.3(a) the JFET SPICE model [12] (which employs the above approximate characteristics) has been used and, also, an improved model due to Sussman-Fort et a l . [13] following criticisms and proposed improvement of the JFET model by Curtice [14]. The chief differences are the use of a better representation of I Dg in the triode region as shown in Fig. 10.3(b) and the introduction of a gate transit time delay. The difference in representation of I Dg shows up in Fig. 10.3(a) but is more important in considering transients. From Fig. 10.3(a) i t is apparent that with a larger magnitude V T the supply voltage needs to be larger to get good V T = -1.37 (M^), V t = -0 .5 (M2) '> separation of the logic levels. This appears again in Fig. 10.4(a) and (b) which shows the simulated transfer 109 F i g . 10.4 B u f f e r t r a n s f e r . a) MESFET(M) v s . J F E T ( J ) : V D D = -0.5 ( M 2 , J 2 ) b) MESFET(M) v s . J F E T ( J ) : V T c h a r a c t e r i s t i c ( V o u t vs V^ n) f o r d i f f e r e n t V T and s u p p l y v o l t a g e s V D D u s i n g b o t h JFET and MESFET models. A computer s i m u l a t i o n of the v o l t a g e t r a n s f e r c h a r a c t e r i s t i c s of the b u f f e r , u s i n g t h e JFET and MESFET models, i s shown i n F i g . 10.4(a) and (b).The MESFET model i s employed f o r s i m u l a t i o n i n F i g . 10.4(c) and ( d ) . In F i g . 10.4(a) and (b) the s w i t c h i n g and l o a d t r a n s i s t o r s a r e i d e n t i c a l . The v o l t a g e g a i n d V Q u t / d V ^ n f o r a s i n g l e s t a g e i s c l o s e t o 1 over a c e r t a i n range f o r a c h o i c e of s u p p l y v o l t a g e s c a l e d w i t h d e v i c e p a r a m e t e r s ( F i g . 1 0 . 4 ( b ) ) . The s i m u l a t i o n of s e v e r a l s t a g e s shown i n F i g . 5 ( c ) and (d) shows t h a t t h e l o g i c h i g h and low l e v e l s s a t u r a t e a t about = 3 V, V T = -1.37 ( M 1 f J T ) , V T - "1.37, Vjjjj - 7 V 110 BUFFER STAGE NUMBER BUFFER STAGE c) d) F i g . 10.4 c) L o g i c l e v e l s as a f u n c t i o n of s e q u e n t i a l s t a g e s where: V D D - 3, d) L o g i c l e v e l s as a f u n c t i o n of s e q u e n t i a l b u f f e r s t a g e s where: V D D = 7, V T = -1.37 (M-j), V T = -0.5 (M 2) V D D ~ I V T I A N O - A T I V T I r e s p e c t i v e l y . 10.4 INVERTER The t r a n s i s t o r s f o r p u l l u p and p u l l d o w n i n t h e b u f f e r w i l l show p r o c e s s v a r i a t i o n s . A l s o as shown i n F i g . 10.4(b) and (d) f o r a t h r e s h o l d v o l t a g e of a c e r t a i n magnitude a s u f f i c i e n t s u p p l y v o l t a g e i s needed t o get w e l l d i s t i n g u i s h e d l o g i c l e v e l s . Hence t h e l o g i c l e v e l s may be l o s t a f t e r a few s t a g e s under c e r t a i n a d v e r s e c o n d i t i o n s . T h i s i n d i c a t e d t h a t an i n v e r t e r w i t h v o l t a g e g a i n g r e a t e r than u n i t y i s r e q u i r e d t o r e g e n e r a t e the o r i g i n a l v a l u e s of the l o g i c l e v e l s . 111 The pr o p o s e d i n v e r t e r , shown i n F i g . 1 0 . 2 ( b ) , c o n s i s t s of a l e v e l s h i f t e r s t a g e and an o u t p u t s t a g e which a c t s l i k e a c o n v e n t i o n a l r a t i o e d l o g i c i n v e r t e r . The use of a r e s i s t o r i n p l a c e of t h e d i o d e s , f o r example as used i n t h e SDFL i n v e r t e r , was chosen because i t appeared t o be e a s i e r t o f a b r i c a t e , s i n c e t h e d i o d e s a r e r e q u i r e d t o be s m a l l and v e r y a c c u r a t e due t o the need f o r r e p r o d u c i b l e c u r r e n t v o l t a g e c h a r a c t e r i s t i c s . The r e s i s t a n c e of t h e i o n i m p l a n t e d r e s i s t o r can be v a r i e d by v a r y i n g t h e dose r a t h e r than t h e d i m e n s i o n s ( w h i c h r e q u i r e s a d i f f e r e n t mask s e t ) . I f s m a l l d i o d e s of e x a c t a r e a a r e used t o o b t a i n s t r a i n on t h e p h o t o l i t h o g r a p h y . I f , i n s t e a d , a s e r i e s c o m b i n a t i o n of l a r g e r d i o d e s i s used (as i n BFL, f o r example) th e n more space and power a r e consumed. When r e p l a c i n g t h e d i o d e s t a c k w i t h a r e s i s t o r the I-V c u r v e s must c o i n c i d e f o r t h e c r i t i c a l s w i t c h i n g r e g i o n q u i e s c e n t c o n d i t i o n t o g i v e t h e same DC t r a n s f e r c h a r a c t e r i s t i c s . The r e s i s t o r i s chosen by p l o t t i n g r e s i s t a n c e v e r s u s o u t p u t v o l t a g e f o r a r e s i s t o r i n p u t v o l t a g e i n the c e n t e r of the l o g i c swing as shown i n F i g . 10.5. When the i n p u t and o u t p u t v o l t a g e s a r e e q u a l a t the l o g i c m i d p o i n t a s y m m e t r i c a l t r a n s f e r c h a r a c t e r i s t i c i s o b t a i n e d . F o r t h e case i n F i g . 10.5(a) and (b) t h i s o c c u r s a t a p p r o x i m a t e l y 2.5 and 0.63 kohm r e s p e c t i v e l y . U s i n g the c r i t e r i o n of e q u a l c u r r e n t f o r a g i v e n v o l t a g e d r o p a t t h e l o g i c m i d p o i n t f o r the d i o d e s t a c k and r e s i s t o r , t he d i o d e s t a c k d i o d e number and a r e a can be 1 12 1Kohm/R IKohm/R a) b) F i g . 10.5 I n v e r t e r o u t p u t v o l t a g e v s . r e c i p r o c a l of the v o l t a g e t r a n s l a t o r r e s i s t o r v a l u e w i t h f i x e d i n p u t v o l t a g e a t ( vOH ~ VOL*/ 2 + vOL' w h e r e vOH s 3 v a n d vOL " °- 2 v - a) V T • -0.5 V, V D D - 3 V, V s s = -2 V b) V T * -1.37 V, V D D = 3 V, V s s = -2 V d e t e r m i n e d once average d i o d e p r o c e s s c o n s t a n t s a r e known. Fo r t h e c a s e i n F i g . 10.5(a) the v o l t a g e d r o p a c r o s s t h e r e s i s t o r i s 1.6 V and t h e c u r r e n t 0.64 mA. I f the d i o d e p r o c e s s i s f i x e d o n l y t h e number of d i o d e s , t h e a r e a , and the s u p p l y v o l t a g e s can be changed. Assuming the same s u p p l y r a i l s , and average d i o d e p r o c e s s c o n s t a n t s from r e f e r e n c e [ 7 ] , a two d i o d e s t a c k would be n e c e s s a r y t o p r o v i d e the v o l t a g e d r o p , w h i c h i f e q u a l i n a r e a would consume 1 nm 2 per d i o d e , f o r a s y m m e t r i c a l t r a n s f e r c h a r a c t e r i s t i c . The I-V c h a r a c t e r i s t i c s of t h e r e s i s t o r and d i o d e s t a c k a r e shown i n F i g . 10.6. I n t h e low i n p u t l o g i c s t a t e the i n v e r t e r w i t h d i o d e s d i s s i p a t e s about 85% l e s s power and i n the h i g h i n p u t l o g i c s t a t e , (assuming the i n v e r t e r i n p u t peaks a t 2 v o l t s ) 113 F i g . 10.6 I-V p l o t s f o r t r a n s l a t o r r e s i s t o r and d i o d e s t a c k . d i s s i p a t e s about t h e same amount of power. However, i f t h e i n v e r t e r i n p u t r i s e s t o t h e s u p p l y r a i l , 3 v o l t s , t h e d i o d e c i r c u i t d i s s i p a t e s about f i v e t i m e s more power than t h e r e s i s t o r c i r c u i t . The d i f f e r e n c e i n dynamic b e h a v i o r t h e r e a f t e r depends on t h e d i o d e s t a c k n o n - l i n e a r i t y . The s i m u l a t e d r e l a t i v e dynamic performance f o r t h e case under c o n s i d e r a t i o n i s shown i n F i g . 10.7. The d i o d e s t a c k c i r c u i t i s p r e d i c t a b l y f a s t e r i n the h i g h t o low t r a n s i t i o n , due t o the d i o d e s t a c k c u r r e n t n o n l i n e a r i t y , but a p p r o x i m a t e l y e q u i v a l e n t t o t h e r e s i s t o r c i r c u i t i n t h e low t o h i g h t r a n s i t i o n , where t h e d e p l e t i o n l o a d must remove the a c c u m u l a t e d c h a r g e . Thus, a l t h o u g h the r e s i s t o r c i r c u i t i s s l o w e r on t h e down t r a n s i t i o n , i t i s d e l a y symmetric making i t a l e s s complex t i m i n g d e s i g n problem f o r l a r g e i n t e r a c t i v e systems, and i t poses a l e s s c r i t i c a l power consumption problem f o r l o g i c 114 F i g . 1 0 . 7 P u l s e r e s p o n s e of b u f f e r and i n v e r t e r . a) B u f f e r : V D D = 5 V w i t h one b u f f e r l o a d . b) I n v e r t e r , R = 629 0, V D D = 3 V , V s s = -2 V , w i t h one b u f f e r l o a d . c) I n v e r t e r c o m p a r i s o n , d i o d e s t a c k v s . r e s i s t o r v e r s i o n , V T = - 0 . 5 V , no l o a d . h i g h i n p u t s . 115 10.5 BUFFERED INVERTER The ICDL i n v e r t e r t u r n s out t o g i v e a r a t h e r low f a n - i n and f a n - o u t , s i m i l a r t o the c a s e w i t h SDFL, a l a r g e c u r r e n t must be d r i v e n i n t o t h e next s t a g e . T h i s problem can be overcome i f the b u f f e r c i r c u i t o r a p p r o p r i a t e l o g i c b l o c k i s added as shown i n F i g . 1 0 . 2 ( c ) . The s i z i n g of t h e b u f f e r t r a n s i s t o r s must acc o u n t f o r the DC l o a d , power d i s s i p a t i o n , and dynamic c o n s i d e r a t i o n s w i t h r e s p e c t t o the i n v e r t e r . 10.6 OR GATE The o p e r a t i o n of the OR l o g i c f o l l o w s from th e d i s c u s s i o n of t h e b u f f e r w i t h degraded dynamic performance due t o t h e added c a p a c i t a n c e . 10.7 AND GATE The p o s i t i v e l o g i c AND as shown i n F i g . 10.2(d) s u f f e r s from a s e v e r e l i m i t a t i o n not p r e s e n t f o r MISFET c i r c u i t s . For l o g i c h i g h i n p u t s f o r w a r d c u r r e n t w i l l f l o w t h r o u g h the S c h o t t k y d i o d e g a t e s of t h e i n p u t t r a n s i s t o r s when gat e s o u r c e v o l t a g e exceeds about 0.7V. The f o u r p o s s i b l e i n p u t l o g i c c o m b i n a t i o n gate c u r r e n t s as a f u n c t i o n of i n p u t v o l t a g e a r e shown i n F i g . 10.8. The w i d t h of T-| i s t a k e n as t w i c e the w i d t h of T 2 and f o u r t i m e s t h e w i d t h of T3 t o m a i n t a i n a r e a s o n a b l e o u t p u t swing f o r the v o l t a g e c o m b i n a t i o n s t h a t a r e a c c e p t a b l e b e f o r e gate f o r w a r d c o n d u c t i o n s e t s i n . The problem can be c i r c u m v e n t e d by u s i n g g a t e s of t h e form of F i g . 10.2(g), i n s t e a d . These a r e ) 116 a) b) F i g . 10.8 S c h o t t k y d i o d e g a t e c u r r e n t of t r a n s i s t o r s a t i n p u t s A and B of AND g a t e of F i g . (2) (d) as a r e s u l t of f i x e d l o g i c l e v e l on A w i t h i n p u t v o l t a g e on B swept. a) A h i g h ( V Q H = 3 V) B swept from 0 t o 3 V. b) A low ( V Q L • 0.2 V) B swept from 0 t o 3 V. c o m b i n a t i o n s of the l o g i c OR of F i g . 1 0 . 2 ( e ) . In summary, i f a l i m i t e d (0.5 V) l o g i c swing i s used, g a t e s such as shown i n F i g . 10.2(d) and ( f ) c o u l d be used. T h i s would g i v e lower power d i s s i p a t i o n compared t o F i g . 1 0 . 2 ( g ) , but p r o b a b l y a t t h e expense of speed and r e l i a b i l i t y . 10.8 RESULTS AND THEIR SPICE SIMULATION The measured parameters used f o r SPICE s i m u l a t i o n f o r 117 e x p e r i m e n t r e s u l t s m a t c h i n g a r e i n T a b l e 10.1. Parameter 2um FET Group 1 Group 2 Group 3 R s o R D SI V T 0(A/V») 68 180 -1.37 2.8- 1 0" 3 100 100 -2.5 200 200 -1.0 400 400 -0.5 or 0 4.4- 1 0 ~ 4 7-10" 4 1 0 r -3 1.4-10 3 5 100 100 5 5 5 5 5 T a b l e 10.1: Measured and S i m u l a t i o n MESFET p a r a m e t r i c d a t a . S i m u l a t i o n d a t a a d j u s t e d from [ 2 0 - 2 3 ] . I n Group 3 l o g i c approaches d e s i g n e d f o r V T = 0 or -0.5 V a r e c o n s i d e r e d , t h u s two v a l u e s of fi were used as l i s t e d , r e s p e c t i v e l y . C a p a c i t a n c e and fi t o r t h e measured d a t a i s t o t a l whereas f o r t h e p a r a m e t r i c d a t a i t i s per u n i t l e n g t h . As shown i n F i g . 10.2(b) e x p e r i m e n t a l c h a r a c t e r i s t i c s were w e l l f i t t e d by t h e MESFET model b o t h i n the s a t u r a t i o n and l i n e a r r e g i o n s . The MESFET model s u c c e s s f u l l y f i t s t he whole DC c h a r a c t e r i s t i c b e t t e r than t h e JFET model. The measured and s i m u l a t e d DC c h a r a c t e r i s t i c s of t h e b u f f e r c i r c u i t and t h e i n v e r t e r a r e shown i n F i g . 1 0 . 4 ( b ) . E x p e r i m e n t a l r e s u l t s c o n f i r m t h e f e a s i b i l i t y p r o j e c t e d by th e s i m u l a t i o n s . The s m a l l d e v i a t i o n between s i m u l a t e d and measured t r a n s f e r c h a r a c t e r i s t i c f o r the b u f f e r c o r r e s p o n d s t o t h e v a r i a t i o n i n the I Q S ~ VDS c h a r a c t e r i s t i c s of the t r a n s i s t o r s from t h e s i m u l a t i o n v a l u e s . S i m u l a t e d dynamic r e s p o n s e s f o r the b u f f e r and the i n v e r t e r a r e g i v e n i n F i g . 10.6. These were o b t a i n e d n e g l e c t i n g p a r a s i t i c s due t o i n t e r c o n n e c t i o n s . The j u s t i f i c a t i o n f o r t h i s i s t h a t t h e s e would depend on d e t a i l s 118 of l a y o u t and we a r e s e e k i n g t h e b a s i c or i n t r i n s i c b e h a v i o r of t h e c i r c u i t . The MESFET model s i m u l a t e d e x p e r i m e n t a l b u f f e r , u s i n g V D D = 5 V, gave an average t i m e d e l a y of 105 ps f o r u n i t y f a n o u t w i t h power d i s s i p a t i o n ( i n p u t h e l d a t t h e l o g i c m i d p o i n t ) of 18.7 mW, and power d e l a y p r o d u c t o f 1.96 p J . The i n v e r t e r gave an average d e l a y of 550 ps u s i n g a b u f f e r c i r c u i t as l o a d w i t h 22.2 mW d i s s i p a t i o n and a power d e l a y p r o d u c t of 12.2 p J per g a t e . REFERENCES 1. R. Van T u y l and C. L i e c h t i , IEEE JSSC, SC-9, No. 5, 269 (1974) . 2. R. Eden, B. Welch, and R. Zucca, IEEE JSSC, SC-13, No. 4, 619 (1978). 3. H. Ishakawa, H. Kusakawa, K. Suyama and M. F u k u t a , I n t . S o l i d - S t a t e C i r c u i t s Conf., D i g . Tech. P a p e r s , 200 (1977). 4. R.A. S a d l e r and L.F. Eastman, IEEE E l e c t r o n Dev. L e t t . , EDL-4, No. 7, 215 (1983). 5. R.E. Lee, H.M. Levy and D.S. Matthews, IEEE GaAs IC Symposium, 177 (1982). 6. K. Yamasaki, K. A s a i and K. Kurumada, Japanese J . A p p l . Phys., 22, Supplement 22-1, 381 (1983). 7. R. A. S a d d l e r , " F a b r i c a t i o n and Performance of Submicron GaAs MESFET D i g i t a l C i r c u i t s by S e l f A l i g n e d Ion I m p l a n t a t i o n , " Ph.D. T h e s i s , C o r n e l l U n i v e r s i t y , ( 1 9 84). 8. R. P e n g e l l y , Microwave F i e l d - E f f e c t T r a n s i s t o r s - T h e o r y D e s i g n and A p p l i c a t i o n s , R e s e a r c h S t u d i e s P r e s s , C h i c h e s t e r ( 1 982). 9. G. N u z i l l a t , F. Damay-Kavala, G. B e r t and C. Arnodo, IEE P r o c , 127, P t . I , No. 5, 287 ( 1980). 10. G. N u z i l l a t , G. B e r t , T.P. Ngu and M. G l o a n e c , IEEE T r a n s . E l e c t r o n Dev., ED-27, No. 6, 1102 (1980). 11. I . M. A b d e l - M o t a l e b , "GaAs MESFETS and T h e i r A p p l i c a t i o n s i n D i g i t a l L o g i c and D i g i t a l t o A n a l o g C o n v e r s i o n " , Ph.D. T h e s i s , U n i v e r s i t y of B r i t i s h C o l u m b i a , (1985). 12. C D . H a r t g r i n g , B.A. R o s a r i o and J.M. P i c k e t t , IEEE JSSC, SC-16, NO. 5, 578 ( 1 9 8 1 ) . 13. L. W. N a g e l , "SPICE 2: A computer program t o s i m u l a t e s e m i c o n d u c t o r c i r c u i t s , " E l e c t r o n i c s R e s e a r c h Lab, C o l . Eng., U n i v e r s i t y of C a l i f o r n i a , B e r k e l e y , Memo. ERL-M520 (1975) . 14. S.E. Sussman-Fort, S. Narasimhan and K. Mayaram, "A Complete GaAs MESFET Computer Model f o r SPICE," IEEE T r a n s . MTT, MTT-32, No. 4, 471 (1984). 15. W.R. C u r t i c e , "A MESFET Model f o r Use i n t h e D e s i g n of 119 120 GaAs I n t e g r a t e d C i r c u i t s , " IEEE T r a n s . MTT, MTT-28, No. 5, 448 (1980). 16. A. L i v i n g s t o n e and D. Welbourn, P r o c . of t h e 14th Conf. on S o l i d S t a t e D e v i c e s , Tokyo, 393 (1982). 17. A. L i v i n g s t o n e , and P. M e l l o r , IEEE P r o c , 127, P t . I , No. 5, 297 ( 1 9 8 0 ) . 18. M. Namordi and W. W h i t e , GaAs IC Symposium, 21 ( 1 9 8 2 ) . 19. A. Bar n a , and C. L i e c h t i , IEEE JSSC, SC-14, No. 4, 708 (1979) 20. M. H e l i x , S. J a m i s o n , S. Hanka, R. V i d a n o , P. Ng, and C. Chao, GaAs IC Symposium, 108 (1982). 21. S. K a t s u , S. Nambu, S. Shimano and G. Kano, IEEE E l e c t r o n Dev. L e t t . , EDL-3, No. 8, 197 (1982) 22. T. Onuma, A. Tamura, T. Uenoyama, H. T s u j i i , K. N i s h i i and H. Y a g i t a , IEEE E l e c t r o n Dev. L e t t . , EDL-4, No. 11, 409 (1983). 23. K. Yamasaki, K. A s a i , K. Kuramada, IEEE T r a n s . E l e c t r o n Dev., ED-29, N O . 11, 1772 (1982) 11. APPENDIX B -LAYOUTS SI3S913T3 ISAB 121 RI26R912T3 ISAB 12. APPENDIX C -GASFET SUBROUTINE SUBROUTINE GASFET IMPLICIT REAL*8 (A-H.O-Z) C C THIS ROUTINE PROCESSES GaAs HESFETS FOR DC AND C TRANSIENT ANALYSES. C BASED ON THE MODEL OF WALTER R. CURTICE C IEEE TRANS ON MICROWAVE THEORY AND TECHNIQUES C VOL MTT-28 NO. 5 MAY 1980 C COMMON /TABINF/IELMNT,ISBCKT,NSBCKT.IUNSAT,NUNSAT,ITEMPS,NUMTEM, 1 ISENS,NSENS,IFOUR,NFOUR,IFIELD,ICODE,IDELIM.ICOLUM.INSIZE. 2 JUNODE.LSBKPT,NUMBKP,IORDER.JMNODE,IUR,IUC,ILC,ILR,NUMOFF,ISR, 3 NMOFFC.ISEQ.ISEQ1.NEQN.NODEVS.NDIAG,ISWAP,IEQUA.MACINS.LVNIM1, 4 LX0,LVN,LYNL,LYU,LYL,LX1,LX2,LX3,LX4,LX5,LX6,LX7,LD0,LD1.LTD, 5 IMYNL,IMVN,LCVN,NSNOD,NSMAT.NSVAL,ICNOD,ICMAT»ICVAL, 6 LOUTPT,LPOL,LZER,IRSWPF,IRSWPR,ICSWPF,ICSWPR,IRPT,JCPT, 7 IROWNO,JCOLNO,NTTBR,NTTAR,LVNTMP COMMON /CIRDAT/LOCATE(50),JELCNT(50 >.NUNODS,NCNODS,NUMNOD,NSTOP, 1 NUT,NLT,NXTRM,NDIST,NTLIN,IBR,NUMVS COMMON /STATUS/OMEGA.TIME,DELTA,DELOLD(7).AGO).VT.XNI,EGFET, 1 XMU,MODE,MODEDC,ICALC,INITF,METHOD,IORD,MAXORD,NONCON,ITERNO. 2 ITEMNO.NOSOLV.MODAC,IPIV,IVMFLG.IPOSTP,ISCRCH,IOFILE COMMON /KNSTNT/TWOPI,XLOG2,XLOG10,ROOT2,RAD,BOLTZ,CHARGE,CTOK, 1 GMINtRELTOL,ABSTOL,VNTOL,TRTOL,CHGTOL,EPSO,EPSSIL,EPSOX. 2 PIVTOL.PIVREL COMMON /BLANK/ VAXUE(200000) INTEGER NODPLC<64) COMPLEX • 16 CVALUE(32) EQUIVALENCE (VALUE<1>,NODPLC(1).CVALUE(1)) C C DIMENSION VGSO(1),VGDO(1),CGO<1>,CDO(1),CGDO(1),GMO(1),GDSO(1). 1 GGSO(1),GGDO(1),QGS(1),CQGS(1),QGD(1),CQGD(1). 2 QDS(1).CQDS(1).QTT<1),CQTT(1> EQUIVALENCE (VGSO(1>.VALUE( 1>>.(VGDO(1>.VALUE( 2)), 1 (CGO <D.VALUE( 3)),(CDO (1).VALDE( 4>), 2 (CGDOO),VALUE( 5)),(GMO ( 1),VALUE( 6)) , 3 <GDSO<1).VALUE( 7)),(GGSO(1),VALUE< 8>), 4 (GGDOO). VALUE < 9)).<QGS ( 1) ,VALUE( 10) > . 5 (CQGS(D.VALUE(11)).<QGD ( 1 > ,VALUE( 12)), 6 (CQGD(1),VALUE(13)),<QDS (1>,VALUE(14)>, 7 (CQDS(1).VALUE(15)),(QTT (1),VALUE<16)), 8 (CQTT(1),VALUE(17)) C C LOC=LOCATE(16) 10 IF (LOC.EQ.0) RETURN LOCV=NODPLC < LOC+1) NODE 1=NODPLC(LOC+2) NODE2=NODPLC(LOC+ 3) NODE 3=NODPLC(LOC+ 4) NODE 4=NODPLC < LOC+5 > NODE5=NODPLC<LOC+6) NODE6=NODPLC< LOC+25) LOCM=NODPLC(LOC+7) IOFF=NODPLC(LOC+ 8) TYPE=NODPLC(LOCM+2) LOCM=NODPLC < LOCM+1) LOCT=NODPLC(LOC+19 > C C DC MODEL PARAMETERS C 123 W l D T H - V A L U E { L O C V + 1 ) V T 0 » V A L U E < L 0 C M + 1 > V B I • V A L U E < L O C M + 2 ) C G A T E P A R A S I T I C C O N D U C T A N C E : G G P R G G P R " V A L U E ( L O C M + 3 > ' W I D T H A L P H A = V A L U E ( L O C M + 4 > B E T A - V A L U E ( L O C M * 5 ) • W I D T H X L A M B - V A L U E < L O C M + 6 ) C S A T - V A L U E ( L O C M * 1 0 ) » W I D T H C D R A I N P A R A S I T I C C O N D U C T A N C E : G D P R G D P R - V A L U E ( L O C M + 1 1 ) » W I D T H C S O U R C E P A R A S I T I C C O N D U C T A N C E : G S P R G S P R - V A L U E ( L O C M + 1 2 ) » W I D T H T A U - V A L U E ( L O C M + 1 3 ) V C R I T - V A L U E < L O C M + 1 4 > C C I N I T I A L I Z A T I O N C I C H E C K = 1 G O T O ( 1 0 0 . 2 0 , 3 0 , 5 0 , 6 0 , 7 0 ) , I N I T F 2 0 I F ( M O D E . N E . 1 . O R . H O D E D C . N E . 2 . O R . N O S O L V . E Q . 0 ) G O T O 2 5 V D S = T Y P E « V A L U E < L O C V + 2 ) V G S - T Y P E • V A L U E ( L O C V + 3 ) V G D ° V G S - V D S G O T O 3 0 0 2 5 I F ( I O F F . N E . O ) G O T O 40 V G S - - 1 . 0 D 0 V G D - - 1 . 0 D 0 G O T O 3 0 0 3 0 I F ( I O F F . E Q . 0 ) G O T O 1 0 0 4 0 V G S - O . O D O V G D - O . O D O G O T O 3 0 0 5 0 V G S = V G S O < L X O + L O C T ) V G D - V G D O ( L X O + L O C T ) G O T O 3 0 0 6 0 V G S = V G S O ( L X 1 + L O C T > V G D - V G D O ( L X 1 + L O C T ) G O T O 3 0 0 7 0 X F A C T - D E L T A / D E L O L D < 2 ) V G S O < L X O + L O C T ) » V G S O < L X 1 + L O C T ) V G S = ( 1 . 0 D 0 + X F A C T > * V G S O ( L X 1 + L O C T > - X F A C T » V G S O < L X 2 + L O C T ) V G D O ( L X 0 + L O C T ) = V G D O < L X 1 + L O C T ) V G D - ( 1 . 0 D 0 + X F A C T ) • V G D O ( L X 1 + L O C T ) - X F A C T * V G D O < L X 2 + L O C T ) C G O < L X O + L O C T > - C G O ( L X 1 + L O C T ) C D O ( L X 0 + L O C T ) = C D O ( L X 1 + L O C T ) C G D O ( L X 0 + L O C T ) « C G D O ( L X 1 + L O C T ) G M O ( L X 0 + L O C T > - G M O < L X 1 + L O C T ) G D S O ( L X 0 + L O C T ) = G D S O < L X 1 + L O C T ) G G S O ( L X O + L O C T > = G G S O ( L X 1 + L O C T ) G G D O ( L X 0 + L O C T ) » G G D O ( L X 1 + L O C T ) G O T O 1 1 0 C C C O M P U T E N E W N O N L I N E A R B R A N C H V O L T A G E S C 1 0 0 V G S - T Y P E * ( V A L U E ( L V N I M 1 + N O D E 6 > - V A L U E ( L V N I M 1 + N O D E 5 ) ) V G D - T Y P E * ( V A L U E ( L V N I M 1 + N O D E 6 ) - V A L U E ( L V N I M 1 + N O D E 4 >) 1 1 0 D E L V G S = V G S - V G S O ( L X 0 + L O C T ) D E L V G D - V G D - V G D O < L X 0 + L O C T > D E L V D S - D E L V G S - D E L V G D C G H A T = C G O ( L X 0 + L O C T ) • G G D O ( L X 0 + L O C T > » D E L V G D + G G S O < L X 0 + L O C T > » D E L V G S C D H A T = C D O ( L X 0 + L O C T ) + G M O ( L X O + L O C T ) * D E L V G S + G D S O < L X O + L O C T ) » D E L V D S 1 - G G D O < L X O + L O C T ) « D E L V G D C BYPASS IF SOLUTION HAS NOT CHANGED C IF (INITF.EQ.6) GO TO 200 TOLoRELTOL»DMAX1< DABS(VGS),DABS(VGSO(LX0+LOCT)> > +VNTOL IF <DABS<DELVGS).GE.TOL) GO TO 200 TOL=RELTOL*DMAX1(DABS(VGD),DABS(VGDO<LXO+LOCT))>+VNTOL IF <DABS(DELVGD).GE•TOL) GO TO 200 TOL=RELTOL*DMAX1(DABS(CGHAT) ,DABS<CGO<LX0+LOCT>) >+ABSTOL IF (DABS(CGHAT-CGO(LX0+LOCT)).GE.TOL) GO TO 200 TOL«RELTOL*DMAX1< DABS(CDHAT),DABS(CDO(LXO+LOCT)))+ABSTOL IF (DABS(CDHAT-CDO(LXO+LOCT)).GE.TOL) GO TO 200 VGS«VGSO(LXO+LOCT> VGD«VGDO(LXO+LOCT) VDS=VGS-VGD CG=CGO(LX0+LOCT) CD«CDO(LXO+LOCT) CGD=CGDO(LXO+LOCT) GM=GMO<LXO+LOCT) GDS»GDSO<LXO+LOCT) GGS«GGSO<LXO+LOCT> GGD=GGDO<LXO+LOCT) GO TO 900 C C LIMIT NONLINEAR BRANCH VOLTAGES C 200 ICHK1-1 CALL PNJLIM<VGS,VGSO(LX0+LOCT).VT.VCRIT,ICHECK) CALL PNJLIM< VGD,VGDO(LXO+LOCT),VT,VCRIT,ICHK1> IF <ICHK1.EQ.O ICHECK«1 CALL FETLIM(VGS,VGSO(LXO+LOCT),VTO) CALL FETLIM(VGD,VGDO(LX0+LOCT),VTO) C C DETERMINE DC CURRENT AND DERIVATIVES C 300 VDS=VGS-VGD IF(VGS.GT.-5.0D0*VT) THEN EVGS=DEXP<VGS/VT) GGS=CSAT*EVGS/VT+GMIN CG=CSAT*(EVGS-1.ODO)+GMIN*VGS ELSE GGS=-CSAT/VGS+GMIN CG'GGS*VGS END IF C IF(VGD.GT.-5.0D0*VT) THEN C EVGD=DEXP(VGD/VT) C GGD=CSAT*EVGD/VT+GMIN C CGDsCSAT*(EVGD-1.0D0)+GMIN*VGD C ELSE C GGD=-CSAT/VGD+GMIN C CGD=GGD*VGD C END IF GGDoGMIN CGD=0.0D0 CG=CG+CGD C C COMPUTE DRAIN CURRENT AND DERIVITIVES C IF(VDS.GE.O) THEN C NORMAL MODE VGST»VGS-VTO IF<VGST.LE.O) THEN C C CUT-OFF SUBTHRESHOLD EFFECTS NOT INCLUDED CDRAINoO.ODO GM-O.ODO GDS =O.ODO ELSE C LINEAR AND SATURATION REGION BETAP=BETA»{1.0D0+XLAMB*VDS) TWOB=BETAP+BETAP CDRAIN=BETAP*VGST*VGST*DTANH(ALPHA*VDS> GM=TWOB*VGST*DTANH(ALPHA*VDS > GDS=XLAMB* BETA*VGST* VGST * DTANH(ALPHA*VDS) + 1 ( B E T A P « V G S T » V G S T * A L P H A * < 1 . 0 D 0 - 2 <DTANH(ALPHA*VDS)*DTANH(ALPHA*VDS)))) END IF ELSE C INVERSE MODE VGDT=VGD-VTO IF(VGDT.LE.O) THEN C CUT-OFF CDRAIN-0.0D0 GM-0.0D0 GDS-O.ODO ELSE C LINEAR AND SATURATION REGION BETAP-BETA*(1.0D0-XLAMB*VDS) TWOB»BETAP+BETAP C CDRAIN«BETAP*VGDT*VGDT*DTANH(ALPHA»VDS) GM=-TWOB*VGDT* DTANH(ALPHA*VDS) GDS=-XLAMB*BETA*VGDT*VGDT*DTANH(ALPHA*VDS)• 1 (BETAP*VGDT*VGDT*ALPHA*(1.0D0- 2 (DTANH(ALPHA*VDS)*DTANH(ALPHA* VDS)))) END IF E N D IF C C C COMPUTE EQUIVALENT DRAIN CURRENT SOURCE C CD=CDRAIN-CGD IF (MODE • NE• 1 ) GO TO 500 IF ((MODEDC.EQ.2).AND.(NOSOLV.NE.O)) GO TO 500 IF (INITF.EQ.4) GO TO 500 GO TO 700 C C CHARGE STORAGE ELEMENTS C 500 CZGS=VALUE<LOCM+7)»WIDTH CZGD=VALUE(LOCM+ 8)«WIDTH CZDS=VALUE(LOCM+9)*WIDTH TW0P=VB1+VBI C C IF VGS APPROACHES VBI NON ZERO CAPGS GOES TO INFINITY C VBI IS SCHOTTKY BARRIER JCT. PLUS 0.5V DUE TO DROP C IN CONDUCTION CHANNEL UNDER GATE C SARG=DSQRT(1.ODO-VGS/VBI) QGS(LXO+LOCT)*TWOP*CZGS* (1. ODO-SARG) CAPGS-CZGS/SARG QGD(LXO+LOCT)=CZGD»VGD C C GATE DRAIN CAPACITANCE HAS BEEN MODIFIED C TO THAT BELOW. C VDS AND VGS INCORPORATED FOR AC AND TRANSIENT ANALYSIS C ADAPTED FROM THE PAPER BY GOLIO ET AL. C IEEE CIRCUITS AND DEVICES MAGAZINE SEPTEMBER 1985 P 21. C VBI ASSUMED TO BE PHIG + CHANNEL DROP<0.5) 127 c CAPGD= (CZGD*(1.0D0-6.OD-1»VGS))/<(1.ODO-<1.23DO»VGS-VDS)/ 1 ( 1 . 2 3 D 0 * ( V B I - 5 . 0 D - 1 ) ) ) » 6 . 6 D - O QDS(LXO+LOCT)=CZDS*VDS CAPDS=CZDS C C QTT IS CHARGE TRANSPORTED UNDER GATE IN TIME TAU C QTT(LXO+LOCT > «TAU*CDRAIN CAPTT=TAU»GM C C STORE SMALL-SIGNAL PARAMETERS C 560 ir <(MODE.EQ.1).AND.(MODEDC.EQ.2).AND.(NOSOLV.NE.O>) GO TO 700 IF (INITF.NE.4) GO TO 600 VALUE(LXO+LOCT+9 >-CAPGS VALUE(LX0+LOCT+11>-CAPGD VALUE < LX0+LOCT+13)=CAPDS VALUE < LX0+LOCT+15)"CAPTT GO TO 1000 C C TRANSIENT ANALYSIS C 600 IF (INITF.NE.5) GO TO 610 QGS(LX1+LOCT > =QGS(LXO+LOCT > QGD < LX1+LOCT)*QGD(LXO+LOCT) QDS < LX1+LOCT)«QDS(LXO+LOCT) QTT(LX1+LOCT >-QTT(LXO+LOCT) 610 CALL INTGR8(GEQ,CEQ,CAPGS,LOCT+9) GGS'GGS+GEQ CG=CG+CQGS(LXO+LOCT) CALL INTGR 8(GEQ,CEQ,CAPGD,LOCT+11) GGD*GGD+GEQ CG-CG+CQGD(LXO+LOCT) CD»CD-CQGD<LXO+LOCT) CGDaCGD+CQGD(LXO+LOCT) CALL INTGR8(GEQ,CEQ,CAPDS,LOCT+13) GDSeGDS+GEQ CD=CD+CQDS(LXO+LOCT) CALL INTGR 8(GEQTT, CEQ,CAPTT,LOCT+15) GM=GM-GEQTT CD-CD-CQTT(LXO+LOCT) IF (INITF.NE.5) GO TO 700 CQGS(LX1+LOCT)«CQGS(LXO+LOCT) CQGD(LX1+LOCT)=CQGD(LXO+LOCT) CQDS(LX1+LOCT)=CQDS(LXO+LOCT) CQTT(LX1+LOCT)«CQTT(LXO+LOCT) C C CHECK CONVERGENCE C 700 IF (INITF.NE.3) GO TO 710 IF (IOFF.EQ.0) GO TO 710 GO TO 750 710 IF (ICHECK.EQ.1) GO TO 720 TOL«RELTOL*DMAX1(DABS(CGHAT),DABS(CG))+ABSTOL IF <DABS(CGHAT-CG).GE.TOL) GO TO 720 TOL=RELTOL»DMAX1(DABS(CDHAT).DABS(CD))+ABSTOL IF (DABS(CDHAT-CD).LE.TOL) GO TO 750 720 NONCON=NONCON+1 750 VGSO(LXO+LOCT)=VGS VGDO(LXO+LOCT>«VGD CGO<LXO+LOCT)=CG CDO(LXO+LOCT)"CD CGDO(LXO+LOCT)=CGD 128 GMO(LXO+LOCT>-GM GDSO(LX0+LOCT)»GDS GGSO(LXO+LOCT)-GGS GGDO(LXO+LOCT>-GGD LOAD CURRENT VECTOR 900 CEQGD-TYPE* < CGD-GGD*VGD) CEQGS=TYPE*((CG-CGD)-GGS«VGS) CDREQ-TYPB*((CD+CGD)-GDS*VDS-GM*VGS) VALUE < LVN+NODE6 >"VALUE < LVN+NODE6)-CEQGS-CEQGD VALUE(LVN+NODE4 >-VALUE(LVN+NODE4)-CDREQ+CEQGD VALUE(LVH+NODE5)-VALUE(LVN+NODE5)+CDREQ+CEQGS LOAD Y MATRIX LOCY-LVN+NODPLC(LOC+20 VALUE < LOCY)"VALUE < LOCY LOCY-LVN+NODPLC(LOC+21 VALUE(LOCY)-VALUE(LOCY LOCY-LVN+NODPLC< LOC+22 VALUE < LOCY)-VALUE(LOCY LOCY-LVN+NODPLC(LOC+23 VALUE(LOCY)-VALUE(LOCY LOCY-LVN+NODPLC(LOC+2 4 VALUE(LOCY >-VALUE(LOCY LOCY-LVN+NODPLC(LOC+26 VALUE(LOCY >-VALUE(LOCY LOCY-LVN+NODPLC(LOC+9) VALUE(LOCY >-VALUE < LOCY LOCY-LVN+NODPLC(LOC+10 VALUE(LOCY >-VALUE(LOCY LOCY-LVN+NODPLC(LOC+11 VALUE(LOCY >-VALUE(LOCY LOCY-LVN+NODPLC(LOC+12 VALUE< LOCY)-VALUE(LOCY LOCY-LVN+NODPLC(LOC+13 VALUE(LOCY >-VALUE(LOCY LOCY-LVN+NODPLC(LOC+14 VALUE(LOCY)-VALUE(LOCY LOCY-LVN+NODPLC< LOC+15 VALUE < LOCY >-VALUE(LOCY LOCY-LVN+NODPLC(LOC+16 VALUE(LOCY)-VALUE(LOCY LOCY-LVN+NODPLC(LOC+17 VALUE(LOCY)-VALUE(LOCY LOCY-LVN+NODPLC < LOC+18 VALUE(LOCY)-VALUE(LOCY LOCY-LVN+NODPLC(LOC+2 7 VALUE < LOCY >-VALUE< LOCY LOCY-LVN+NODPLC(LOC+2 8 VALUE(LOCY)-VALUE(LOCY 1000 LOC=NODPLC<LOC) GO TO 10 END •GDPR +GGD+GGS+GGPR •GSPR +GDPR +GDS +GGD +GSPR+GDS+GM+GGS +GGPR •GDPR -GGD -GGS -GSPR -GDPR +GM-GGD -GDS-GM -GGS-GM -GSPR -CDS -GGPR -GGPR 13. APPENDIX D -SIMULATION SOURCE LISTINGS PROCESS TEST 100 um MESFET CHARACTERIZATION •Cycle Controls .OPTIONS ITL4-1000 ITL5»0 LIMPTS=2000 NOPAGE NOMOD * •Lis t ing Options .WIDTH OOT=80 • •Active Elements •Bn ND NG NS GFETn (width in urn) B1 1 2 0 SI12 100 B2 3 4 0 SI12 100 B3 5 6 0 S112 100 B4 7 8 0 SH2 100 B5 9 10 0 S112 100 * •Active Element Models •model is for 1 urn s l ice of MESFET which is multiplied by length •factor in device definit ion * .MODEL S112 GASFET(VTO'-2, VBI-1.23, RC0.13 , ALPHA-2.3, BETA=2.61E-5 + LAMBDA»0.055, CGS0-1.19FF, CGD=1.19FF, CDS=0.096FF, IS=4.13E-15, • RD-3228, RS-3228, TAU-2.86PS) • •Independent Sources VDS 11 0 VDS 1 11 1 DC 0 VGS1 2 0 DC -1.5 VDS2 11 3 DC 0 VGS2 4 0 DC -1 VDS3 11 5 DC 0 VGS3 6 0 DC -0.5 VDS4 11 7 DC 0 VGS 4 8 0 DC 0 VDS5 11 9 DC 0 VGS5 10 0 DC 0.5 • •DC Analysis Parameters .DC VDS 0 3 0.025 • •Output Parameters .PRINT DC I(VDS1> I(VDS2) I(VDS3) I(VDS4) l(VDS5) • END ISAB RI36R912T3 Strobe Pulse Distortion • •Cycle Controls and Lis t ing Options .OPTIONS ITL4=1000 ITL5=0 LIMPTS=2000 NOPAGE NOMOD .WIDTH OHT=80 * • • • • • • • • • • • • • I S A B Circuit******* • BSG1 7 24 6 R12G1 BSS 9 26 8 R12S 60 BSG2 11 24 10 R12G2 VI 23 6 0 V2 7 8 0 V3 9 10 0 V4 1 1 20 0 V5 25 26 0 * XAMP1 20 21 1 2 AMP •ISAB Circui t Passive and Parasit ic Components 129 CFIXED 11 0 9FF CSPAD 25 0 10FF CRFPAD 23 0 20FF CGPAD 24 0 2OFF LSIN 15 25 0.16NH LRFIN 13 23 0.16NH LGIN 14 24 0.16NH RSIN 5 15 50 RRFIN 3 13 50 RGIN 4 14 50 • «»**»****«End ISAB Circuit******* •Amplifier Subcircuit • .SOBCKT AMP 3 5 12 BIN 4 3 0 RSAG12 67 BFB 4 5 0 RSAG12 23 BLPU 2 4 4 RSAG12 45 BPU 2 4 6 RSAG12 90 D1 6 7 TD4 66 D2 7 8 TD4 66_ D3 8 5 TD4 66 BPD 5 1 1 RSAG12 90 .ENDS AMP • •Active Element Models .MODEL RSAG12 GASFET(VTO--2. VBI-1.23, RG-0.83, ALPHA-2.3, BETA-3.1E- + LAMBDA-0.055. CGS0-0.595FF, CGD-0.595FF, CDS-0.0791FF. IS-2.07E-15, • RD-1170, RS-1170. TAO-0.71PS) .MODEL R12G1 GASFET<VTO=-2, VBI-1.23, RG-4.97, ALPHA-2.3, BETA-3.1E-5 • LAMBDA-0.055, CGSO-0.595FF, CGD-0.595FF, CDS-0.0791FF, IS-2.07E-15, + RD-705, RS-1170, TAU-0.71PS) .MODEL R12S GASFET<VTO--2, VBI-1.23, RG-4.97, ALPHA-2.3, BETA-3.1E-5 + LAMBDA-0.055, CGS0-0.595FF, CGD-0.595FF, CDS-0.0791FF, IS-2.07E-15, + RD-705, RS-705, TAU-0.71PS) .MODEL R12G2 GASFET<VTO--2, VBI-1.23, RG-0.83, ALPHA-2.3, BETA-3.1E-5 + LAMBDA-0.055, CGS0-0.595FF, CGD-0.595FF, CDS-0.0791FF, IS-2.07E-15, + RD-1170, RS-705, TAO-0.71PS) • .MODEL TD4 D(IS-.312E-12, RS-1745, N-1.1, TT-.59PS, CJO-8.02E-15, + VJ-0.72, EG-1.42, BV-8, IBV-1E-3) • •Independent Sources VDD 2 0 4.5 VSS 1 0 -3 * •Strobe Pulse Distortion due to Parasit ics » VSIN 5 0 POLSE(-2.9 -.3 5PS 5PS 5PS 25PS 200PS) VRFB 3 0 -0.6 VGGB 4 0 -0.3 .TRAN 0. 1PS 50PS .PRINT TRAN V(5) V(25> . END ISAB RI36R912T3 Time Constant Determination * •Cycle Controls and List ing Options .OPTIONS ITL4-1000 ITL5-0 LIMPTS-2000 NOPAGE NOMOD .WIDTH OUT-80 • ******«»*»*«*XSAB Circuit******* * BSG1 7 24 6 R12G1 BSS 9 26 8 R12S 60 BSG2 11 24 10 R12G2 VI 23 6 0 V2 7 8 0 V3 9 10 0 V4 11 20 0 V5 25 26 0 • XAMP1 20 21 1 2 AMP •ISAB Circu i t Passive and Parasit ic Components CFIXED 11 0 9FF • • • • • • • • • • • E n d ISAB Circuit******* •Amplifier Subcircuit • .SOBCKT AMP 3 5 12 BIN 4 3 0 RSA612 67 BFB 4 5 0 RSAG12 23 BLPU 2 4 4 RSAG12 45 BPU 2 4 6 RSAG12 90 Dl 6 7 TD4 66 D2 7 8 TD4 66 D3 8 5 TD4 66 BPD 5 1 1 RSAG12 90 • ENDS AMP « •Active Element Models • MODEL RSAG12 GASFET(VTO«- 2, VBI-1.23, RG-0.83, ALPHA-2.3, BETA-3.1E-5 + LAMBDA-0.055, CGS0-0.595FF, CGD-0.595FF. CDS-0.0791FF. IS-2.07E-15. + RD-1170, RS-1170. TAU-0.71PS) •MODEL R12G1 GASFET(VTO-- 2, VBI-1.23. RG-0.83, ALPHA-2.3, BETA-3.1E-5 + LAMBDA-0.055, CGS0-0.595FF, CGD-0.595FF. CDS»0.0791FF, IS-2.07E-15. + RD-705, RS-1170, TAU-0.71PS) •MODEL R12S GASFET(VTO--2, VBI-1.23, RG-0.83. ALPHA-2.3, BETA-3.1E-5 + LAMBDA-0.055, CGSO-0.595FF, CGD-0.595FF. CDS-0.0791FF, IS-2.07E-15. • RD-705. RS-705, TAU-0.71PS) .MODEL R12G2 GASFET<VTO--2, VBI-1.23, RG-0.83, ALPHA-2.3, BETA=3.1E-5 + LAMBDA-0.055, CGS0-0.595FF. CGD-0.595FF, CDS-0.0791FF, IS-2.07E-15, + RD-1170, RS-705. TAU-0.71PS) • .MODEL TD4 D<IS=.312E-12, RS-1745, N-1.1. TT-.59PS, CJO-8.02E-15, • VJ-0.72, EG-1.42, BV-8. IBV-1E-3) • •Independent Sources VDD 2 0 4.5 VSS 1 0 -3 • •Input Time Constant Determination * VSGB 25 0 -0.3 VGGB 24 0 -0.3 VRFIN 23 0 -0.6 PWL(0PS -.8 0.1PS -.4 100PS -0.4 100.IPS -0.8 200PS -0. .TRAN 2PS 200PS .PRINT TRAN V(6) V(20) . END ISAB RI36R912T3 Pulse Feedthrough at vbias • •Cycle Controls and Lis t ing Options .OPTIONS ITL4-1000 ITL5-0 LIMPTS-2000 NOPAGE NOMOD .WIDTH OUT-80 * • * • * • • • • • • * • • I S A B Circuit******* • BSG1 7 24 6 R12G1 BSS 9 26 8 R12S 60 BSG2 11 24 10 R12G2 VI 23 6 0 V2 7 8 0 V3 9 10 0 V4 11 20 0 V5 25 26 0 • XAMP1 20 21 1 2 AMP •ISAB Circui t Passive and Parasitic Components CFIXED 11 0 9FF CRFPAD 23 0 2OFF CGPAD 24 0 2OFF LRFIN 13 23 0.16NH LGIN 14 24 0.16NH RRFIN 3 13 50 RGIN 4 14 50 • «********«End ISAB Circuit******* •Amplifier Subcircuit » .SOBCKT AMP 3 5 12 BIN 4 3 0 RSAG12 67 BFB 4 5 0 RSAG12 23 BLPU 2 4 4 RSAG12 45 BPU 2 4 6 RSAG12 90 DI 6 7 TD4 66 D2 7 8 TD4 66 D3 8 5 TD4 66 BPD 5 1 1 RSAG12 90 .ENDS AMP • •Active Element Models .MODEL RSAG12 GASFET<VTO--2, VBI-1.23, RG-0.83, ALPHA-2.3, BETA-3.1E-5 + LAMBDA-0.055, CGSO-0.595FF, CGD-0.595FF. CDS-0.0791FF, IS-2.07E-15, + RD-1170, RS-1170. TAU-0.71PS) .MODEL R12G1 GASFET(VTO«-2, VBI-1.23, RG-0.83, ALPHA-2.3, BETA-3.1E-5 + LAMBDA-0.055, CGS0-0.595FF, CGD-0.595FF, CDS-0.0791FF, IS-2.07E-15, • RD-705, RS-1170, TAO-0.71PS) .MODEL R12S GASFET(VTO«-2. VBI-1.23, RG-0.83, ALPHA-2.3, BETA-3.1E-5 + LAMBDA-0.055, CGS0-0.595FF, CGD-0.595FF, CDS-0.0791FF, IS-2.07E-15, • RD-705, RS-705, TAO-0.71PS) .MODEL R12G2 GASFET(VTO=-2, VBI-1.23, RG-0.83, ALPHA-2.3, BETA-3.1E-5 + LAMBDA-0.055, CGS0-0.595FF, CGD-0.595FF, CDS-0.0791FF, IS-2.07E-15, + RD-1170, RS-705, TAU-0.71PS) • .MODEL TD4 D<IS-.312E-12, RS-1745, N-1.1, TT-.59PS, CJO-8.02E-15, • VJ-0.72, EG-1.42, BV-8, IBV-1E-3) * •Independent Sources VDD 2 0 4.5 VSS 1 0 -3 * •Pulse Feedthrough at vbias • VSIN 25 0 POLSE(-2.9 -.3 5PS 5PS 5PS 25PS 200PS) VGGB 4 0 -0.3 VRFB 3 0 -0.6 .TRAN 0.1PS 50PS .PRINT TRAN V<26) V(23) V(20) . END ISAB RI36R912T3 Off Isolation at 10GHz * •Cycle Controls and List ing Options .OPTIONS ITL4-1000 ITL5-0 LIMPTS-2000 NOPAGE NOMOD .WIDTH OUT-80 « • • • • « * * * « « * t * I S A B Circuit******* 133 BSG1 7 24 6 R12G1 BSS 9 26 8 R12S 60 BSG2 11 24 10 R12G2 V1 23 6 0 V2 7 8 0 V3 9 10 0 V4 11 20 0 V5 25 26 0 • XAMP1 20 21 1 2 AMP •ISAB Circui t Passive and Parasit ic Components CFIXED 11 0 9FF * t*****»***End ISAB Circuit******* •Amplifier Subcircuit * .SUBCKT AMP 3 5 12 BIN 4 3 0 RSAG12 67 BFB 4 5 0 RSAG12 23 BLPU 2 4 4 RSAG12 45 BPU 2 4 6 RSAG12 90 DI 6 7 TD4 66 D2 7 8 TD4 66 D3 8 5 TD4 66 BPD 5 1 1 RSAG12 90 •ENDS AMP * •Active Element Models • MODEL RSAG12 GASFET(VTO--2. VBI-1.23, RG-0.83, ALPHA-2.3, BETA-3.1E-5 + LAMBDA-0.055, CGS0-0.595FF, CGD-0.595FF, CDS-0.0791FF, IS-2.07E-15, + RD-1170, RS-1170, TAU-0.71PS) .MODEL R12G1 GASFET(VTO=-2, VBI-1.23, RG-0.83, ALPHA-2.3. BETA-3.1E-5 + LAMBDA-0.055, CGS0-0.595FF. CGD-0.595FF, CDS-0.0791FF, IS-2.07E-15, + RD-705, RS-1170, TAU-0.71PS) .MODEL R12S GASFET<VTO--2, VBI-1.23, RG-0.83, ALPHA-2.3, BETA-3.1E-5 + LAMBDA-0.055, CGSO-0.595FF, CGD-0.595FF, CDS-0.0791FF, IS-2.07E-15, • RD-705, RS-705, TAU-0.71PS) .MODEL R12G2 GASFET(VTO--2, VBI-1.23, RG-0.83, ALPHA-2.3, BETA-3.1E-5 + LAMBDA-0.055, CGS0-0.595FF, CGD-0.595FF, CDS-0.0791FF, IS-2.07E-15, • RD-1170, RS-705, TAU-0.71PS) « .MODEL TD4 D(IS-.312E-12, RS-1745, N-1.1, TT-.59PS, CJO-8.02E-15, + VJ-0.72, EG-1.42, BV-8, IBV-1E-3) • • I n d e p e n d e n t Sources VDD 2 0 4.5 VSS 1 0 -3 • •Off Isolation with 10 GHz Sine RF Input * RSHUNT 23 20 15M VRFIN 23 0 SIN<-0.6 0.2 10GHZ) VSGB 25 0 -2.9 VGGB 24 0 -0.3 .TRAN 2PS 100PS .PRINT TRAN V<23) V(20) V(21) .END ISAB RI36R912T3 Open Switch Tracking • •Cycle Controls and List ing Options .OPTIONS ITL4-1000 ITL5-0 LIMPTS-2000 NOPAGE NOMOD .WIDTH OUT-80 * «»**«********ISAB Circuit******* BSG1 7 24 6 R12G1 BSS 9 26 8 R12S 60 BSG2 11 24 10 R12G2 V1 23 6 0 V2 7 8 0 V3 9 10 0 V4 11 20 0 V5 25 26 0 • ZAMP1 20 21 1 2 AMP •ISAB Circu i t Passive and Parasit ic Components CFIXED 11 0 9FF * • • • • • • • • • • g n d ISAB Circuit******* •Amplifier Subcircuit * .SOBCKT AMP 3 5 12 BIN 4 3 0 RSAG12 67 BFB 4 5 0 RSAG12 23 BLPU 2 4 4 RSAG12 45 BPU 2 4 6 RSAG12 90 Dl 6 7 TD4 66 D2 7 8 TD4 66 D3 8 5 TD4 66 BPD 5 1 1 RSAG12 90 .ENDS AMP • •Active Element Models .MODEL RSAG12 GASFET(VTO--2, VBI-1.23, RG-0.83, ALPHA-2.3, BETA-3.1E-5 • LAMBDA-0.055, CGS0=0.595FF, CGD=0.595FF. CDS-0.0791FF, IS-2.07E-15. + RD-1170, RS-1170. TAU-0.71PS) .MODEL R12G1 GASFET( VTO--2, VBI-1.23, RG-0.83, ALPHA-2.3, BETA-3.1E-5 + LAMBDA-0.055, CGS0-O.595FF, CGD-0.595FF, CDS-0.0791FF, IS-2.07E-15, + RD-705, RS-1170, TAU-0.71PS) .MODEL R12S GASFET(VTO--2, VBI-1.23, RG-0.83, ALPHA-2.3, BETA-3.1E-5 + LAMBDA-0.055, CGS0-0.595FF, CGD-0.595FF, CDS-0.0791FF, IS-2.07E-15, + RD-705, RS-705, TAU-0.71PS) .MODEL R12G2 GASFET<VTO--2, VBI-1.23, RG-0.83, ALPHA-2.3, BETA-3.1E-5 + LAMBDA-0.055, CGS0-0.595FF, CGD-0.595FF, CDS-0.0791FF. IS-2.07E-15, + RD-1170, RS-705, TAU-0.71PS) • .MODEL TD4 D<IS-.312E-12, RS-1745, N-1.1, TT-.59PS, CJO-8.02E-15, • VJ-0.72, EG-1.42, BV-8, IBV-1E-3) • •Independent Sources VDD 2 0 4.5 VSS 1 0 -3 • Sine wave Tracking Open Switch * VRFIN 23 0 SIN(-0.6 0.2 1GH2) VSGB 25 0 -0.3 VGGB 24 0 -0.3 .TRAN 10PS INS .PRINT TRAN V<23) V(20) V(21) .END ISAB RI36R912T3 Tracking at 2.3Tau Aperture • •Cycle Controls and List ing Options .OPTIONS ITL4-1000 ITL5-0 LIMPTS-2000 NOPAGE NOMOD .WIDTH OUT-80 « • • • • • • • • • • • • • I S A B Circuit******* BSG1 7 24 6 R12G1 BSS 9 26 8 R12S 60 BSG2 11 24 10 R12G2 VI 23 6 0 V2 7 8 0 V3 9 10 0 Vt 11 20 0 V5 25 26 0 • ZAHP1 20 21 1 2 AMP •ISAB Circu i t Passive and Parasit ic Components CFIXED 11 0 9FF • • • • • • • • • • • E n d ISAB Circuit******* •Amplifier Subcircuit * .SOBCKT AMP 3 5 12 BIN 4 3 0 RSAG12 67 BFB 4 5 0 RSAG12 23 BLPU 2 4 4 RSAG12 45 BPU 2 4 6 RSAG12 90 Dl 6 7 TD4 66 D2 7 8 T04 66 D3 8 5 TD4 66 BPD 5 1 1 RSAG12 90 .ENDS AMP • •Active Element Models .MODEL RSAG12 GASFET(VTO--2. VBI-1.23, RG-0.83, ALPHA-2.3, BETA-3.1E-5 + LAMBDA-0.055, CGS0-0.595FF, CGD-0.595FF, CDS-0.0791FF, IS-2.07E-15, + RD-1170, RS-1170, TAU-0.71PS) .MODEL R12G1 GASFET(VTO--2, VBI-1.23, RG-0.83, ALPHA-2.3, BETA-3.1E-5 + LAMBDA-0.055, CGSO-0.595FF, CGD-0.595FF, CDS-0.0791FF, IS-2.07E-15, + RD-705, RS-1170, TAU-0.71PS) .MODEL R12S GASFET(VTO--2, VBI-1.23, RG-0.83, ALPHA-2.3, BETA-3.1E-5 • LAMBDA-0.055, CGS0-0.S95FF, CGD-0.595FF, CDS-0.0791FF, IS-2.07E-15, • RD-705, RS-705, TAU-0.71PS) .MODEL R12G2 GASFET(VTO--2, VBI-1.23, RG-0.83, ALPHA-2.3, BETA-3.1E-5 + LAMBDA-0.055, CGS0-0.595FF, CGD-0.595FF, CDS-0.0791FF, IS-2.07E-15, + RD-1170, RS-705, TAU-0.71PS) « .MODEL TD4 D( IS- '• 312E-12 , RS-1745, N-1.1, TT-.59PS, CJO-8. 02E-15, • VJ-0.72, EG-1.42, BV-8, IBV«1E-3> • •Independent Sources VDD 2 0 4.E VSS 1 0 - 3 * •Sine Have Tracking at Sampling Aperture 2.3Tau * VRFIN 23 0 SIN("0.6 0.2 1GHZ) VSIN 25 0 PULSE(-2.9 -.3 5PS 5PS 5PS 57.5PS 100PS) VGGB 24 0 -0.3 .TRAN 1PS INS .PRINT TRAN V(26) V(23) V(20) V(21) • END ISAB RI36R912T3 Tracking at Tau Aperture • •Cycle Controls and List ing Options .OPTIONS ITL4-1000 ITL5-0 LIMPTS-2000 NOPAGE NOMOD .WIDTH OUT-80 • • • • • • • • • • • • • • I S A B Circuit******* * BSG1 7 24 6 R12G1 BSS 9 26 8 R12S 60 BSG2 11 24 10 R12G2 VI 23 6 0 V2 7 8 0 V3 9 10 0 V4 11 20 0 V5 25 26 0 • XAMP1 20 21 1 2 AMP •ISAB Circu i t Passive and Parasit ic Components CFIXED 11 0 9FF • • • • • • • • • • • E n d ISAB Circuit******* •Amplifier Subcircuit • .SOBCKT AMP 3 5 12 BIN 4 3 0 RSAG12 67 BFB 4 5 0 RSAG12 23 BLPU 2 4 4 RSAG12 45 BPU 2 4 6 RSAG12 90 D1 6 7 TD4 66 D2 7 8 TD4 66 D3 8 5 TD4 66 BPD 5 1 1 RSAG12 90 • ENDS AMP • •Active Element Models .MODEL RSAG12 GASFET(VTO--2, VBI-1.23, RG-0.83, ALPHA-2.3, BETA-3.1E-5 + LAMBDA-0.055, CGS0-0.595FF, CGD-0.595FF, CDS-0.0791FF, IS-2.07E-15, • RD-1170, RS-1170, TAU-0.71PS) .MODEL R12G1 GASFET<VTO--2, VBI-1.23, RG-0.83, ALPHA-2.3, BETA-3.1E-5 + LAMBDA-0.055, CGS0-0.595FF, CGD-0.595FF, CDS-0.0791FF, IS-2.07E-15, + RD-705, RS-1170, TAU-0.71PS) .MODEL R12S GASFET(VTO--2, VBI-1.23, RG-0.83, ALPHA-2.3, BETA-3.1E-5 • LAMBDA-0.055, CGS0-0.595FF, CGD-0.595FF, CDS-0.0791FF, IS-2.07E-15, + RD-705, RS-705, TAU-0.71PS) .MODEL R12G2 GASFET(VTO--2, VBI-1.23, RG-0.83, ALPHA-2.3, BETA-3.1E-5 • LAMBDA-0.055, CGS0-0.595FF, CGD-0.595FF, CDS-0.0791FF, IS-2.07E-15, + RD-1170, RS-705, TAU-0.71PS) • .MODEL TD4 D<IS-.312E-12, RS-1745, N-1.1, TT-.59PS, CJO-8.02E-15, + VJ-0.72, EG-1-42, BV-8, IBV-1E-3) • •Independent Sources VDD 2 0 4.5 VSS 1 0 -3 * •Sine wave Tracking at Sampling Aperture Tau * VRFIN 23 0 SIN<-0.6 0.2 1GHZ) VSIN 26 0 PULSE(-2.9 -.3 5PS 5PS 5PS 25PS 100PS) VGGB 4 0 -0.3 .TRAN 1PS 1NS .PRINT TRAN V(26) V{23) V<20) V(21) .END ISAB RI26R912T3 Time Constant Determination * •Cycle Controls and List ing Options .OPTIONS ITL4-1000 ITL5-0 LIMPTS-2000 NOPAGE NOMOD .WIDTH OUT-80 • • • • • • • • • • • • • • I S A B Circuit******* * BSS 9 26 6 R12S 60 BSG2 11 24 10 R12G2 VI 23 6 0 V3 9 10 0 V4 11 20 0 V5 25 26 0 * XAMP1 20 21 1 2 AMP •ISAB Circui t Passive and Parasit ic Components CFIXED 11 0 39FF • •*«*******End ISAB Circuit******* •Amplifier Subcircuit • .SUBCKT AMP 3 5 12 BIN 4 3 0 RSAG12 67 BFB 4 5 0 RSAG12 23 BLPU 2 4 4 RSAG12 45 BPU 2 4 6 RSAG12 90 DI 6 7 TD4 66 D2 7 8 TD4 66 D3 8 5 TD4 66 BPD 5 1 1 RSAG12 90 • ENDS AMP • •Active Element Models .MODEL R12S GASFET(VTO--2, VBI-1.23, RG-0.83, ALPHA-2.3, BETA-3.1E-5 • LAMBDA=0.055, CGSO-0.595FF, CGD=0.595FF, CDS-0.0791FF, IS-2.07E-15. + RD=705, RS-1170, TAU-0.71PS) .MODEL R12G2 GASFET(VTO--2, VBI-1.23, RG-0.83, ALPHA-2.3, BETA-3.1E-5 •» LAMBDA-0.055, CGS0=0. 595FF, CGD-0.595FF, CDS-0.079 IFF, IS-2. 07E-1 5, + RD-1170, RS-705, TAU-0.71PS) .MODEL RSAG12 GASFET(VTO--2, VBI-1.23, RG«0.83, ALPHA"2.3, BETA-3.1E-5 • LAMBDA-0.055, CGS0=0.595FF, CGD=0.595FF. CDS-0.0791FF. IS-2.07E-15, + RD-1170, RS-1170, TAU-0.71PS) « .MODEL TD4 D<IS-.312E-12, RS-1745, N-1.1, TT-.59PS, CJO-8.02E-15, + VJ-0.72, EG-1.42, BV-8, IBV-1E-3) • •Independent Sources VDD 2 0 4.5 VSS 1 0 - 3 • •Input Time Constant Determination • VSGB 25 0 -0.3 VGGB 24 0 -0.3 VRFIN 23 0 -0.6 PWL(0PS -.8 0.1PS -.4 100PS -0.4 100.1PS -0.8 200PS -0. .TRAN 2PS 2OOPS .PRINT TRAN V(6) V<20> .END ISAB RI26R912T3 Pulse Feedthrough * •Cycle Controls and List ing Options .OPTIONS ITL4-1000 ITL5-0 LIMPTS-2000 NOPAGE NOMOD .WIDTH OUT-80 • «***««««*«**«iSAB Circuit******* • BSS 9 26 6 R12S 60 BSG2 11 24 10 R12G2 VI 23 6 0 V3 9 10 0 V4 11 20 0 V5 25 26 0 • XAMP1 20 21 1 2 AMP 1 138 •ISAB Circui t Passive and Parasit ic Components CFIXED 11 0 39FF • • • • • • • • • • • E n d ISAB Circuit******* •Amplifier Subcircuit • •SOBCKT AMP 3 5 1 2 BIN 4 3 0 RSAG12 67 BFB 4 5 0 RSAG12 23 BLPU 2 4 4 RSAG12 45 BPU 2 4 6 RSAG12 90 01 6 7 TD4 66 D2 7 8 TD4 66 D3 8 5 TD4 66 BPD 5 1 1 RSAG12 90 .ENDS AMP • •Active Element Models .MODEL R12S GASFET(VTO--2, VBI-1.23, RG-0.83, ALPHA-2.3, BETA-3.1E-5 + LAMBDA=0.055, CGS0-0.595FF, CGD-0.595FF, CDS-0.0791FF, IS-2.07E-15, + RD-705, RS-1170, TAU-0.71PS) .MODEL R12G2 GASFET(VTO--2, VBI-1.23, RG«0.83, ALPHA-2.3, BETA-3.1E-5 + LAMBDA-0.055, CGS0-0.595FF, CGD-0.595FF, CDS-0.0791FF, IS-2.07E-15, • RD-1170, RS-705, TAU-0.71PS) .MODEL RSAG12 GASFET(VTO--2, VBI-1.23, RG-0.83. ALPHA-2.3, BETA-3.1E-5 + LAMBDA-0.055, CGS0-0.595FF, CGD-0.595FF, CDS-0.0791FF, IS-2.07E-15, + RD-1170, RS-1170, TAU-0.71PS) • .MODEL TD4 D(IS-.312E-12, RS-1745, N-1.1, TT-.59PS, CJO-8.02E-15, • VJ-0.72, EG-1.42, BV-8, IBV-1E-3) • •Independent Sources VDD 2 0 4.5 VSS 1 0 -3 • •Pulse Feedthrough at vbias * VSIN 25 0 PULSE(-2.9 -.3 5PS 5PS 5PS 25PS 200PS> VGGB 24 0 -0.3 VRFB 23 0 -0.6 .TRAN 0.1PS 50PS .PRINT TRAN V(26> V(23> V(20) . END ISAB RI26R912T3 Off Isolation • •Cycle Controls and List ing Options .OPTIONS ITL4-1000 ITL5-0 LIMPTS-2000 NOPAGE NOMOD .WIDTH OUT-80 • • • • • • • • • • • • • • I S A B Circuit******* • BSS 9 26 6 R12S 60 BSG2 11 24 10 R12G2 VI 23 6 0 V3 9 10 0 V4 11 20 0 V5 25 26 0 • XAMP1 20 21 12 AMP •ISAB Circui t Passive and Parasit ic Components CFIXED 11 0 39FF • • • • • • • • • • • E n d ISAB Circuit******* •Amplifier Subcircuit .SUBCKT AMP 3 5 1 2 BIN 4 3 0 RSAG12 67 BFB 4 5 0 RSAG12 23 BLPU 2 4 4 RSAG12 45 BPU 2 4 6 RSAG12 90 D1 6 7 TD4 66 D2 7 8 TD4 66 D3 8 5 TD4 66 BPD 5 1 1 RSAG12 90 .ENDS AMP * •Active Element Models .MODEL R12S GASFET<VTO«-2, VBI=1.23, RG=0.83, ALPHA=2.3, BETA«3.1E-5 + LAMBDA=0.055, CGS0=0.595FF, CGD=0.595FF, CDS*0.079 IFF, I S « 2 . 0 7 E - 1 5 , + RD=705, RS=1170. TAU-0.71PS) .MODEL R12G2 GASFET(VTO=-2, V B I « 1 . 2 3 , RG»0.83, ALPHA=2.3, BETA=3.1E-5 + LAMBDA=0.055, CGS0=0.595FF, CGD«0.595FF, CDS=0.0791FF, IS=2.07E-15, • RD=1170, RS=705, TAU=0.71PS) .MODEL RSAG12 GASFET(VT0=-2, VBI=1.23, RG=0.83, ALPHA»2.3, BETA=3.1E"5 • LAMBDA«0.055, CGSO=0.595FF, CGD=0.59SFF, CDS=0.0791FF, IS=2.07E-15, + RD=1170, RS*1170^ TAU*0.71PS) • .MODEL TD4 D<IS» .312E-12 , RS-1745, N=1.1, TT=.59PS, CJO«8.02E-15, • VJ-0.72. EG'1.42, BV«»8, IBV«1E-3) • •Independent Sources VDD 2 0 4.5 VSS 1 0 -3 • •Ott Isolation with 10 GHz Sine RF Input • RSHUNT 23 20 10M VRFIN 23 0 SIN(-0.6 0.2 10GHZ) VSGB 25 0 -2.9 VGGB 24 0 -0.3 .TRAN 2PS 100PS •PRINT TRAM V(23> V<20> V<21> • END ISAB RI26R912T3 Open Switch Tracking • •Cycle Controls and List ing Options •OPTIONS ITL4-1000 ITL5=0 LIMPTS«2000 NOPAGE NOMOD .WIDTH OUT=80 • •••**********ISAB Circuit******* * BSS 9 26 6 R12S 60 BSG2 11 24 10 R12G2 VI 23 6 0 V3 9 10 0 V4 11 20 0 V5 25 26 0 * XAMP1 20 21 1 2 AMP •ISAB Circui t Passive and Parasit ic Components CFIXED 11 0 39FF * • • • • • • • • • • E n d ISAB Circuit******* •Amplifier Subcircuit * .SUBCKT AMP 3 5 12 BIN 4 3 0 RSAG12 67 BFB 4 5 0 RSAG12 23 BLPU 2 4 4 RSAG12 45 BPU 2 4 6 RSAG12 90 140 Dl 6 7 TD4 66 D2 7 8 TD4 66 D3 8 5 TD4 66 BPD 5 1 1 RSAG12 90 .ENDS AMP • •Active Element Models .MODEL R12S GASFET(VTO--2, VBI-1.23, RG-0.83, ALPHA-2.3, BETA-3.1E-5 • LAMBDA-0.055, CGS0-0.595FF, CGD-0.595FF. CDS-0.0791FF, IS-2.07E-15, + RD-705, RS-1170, TAU-0.71PS) .MODEL R12G2 GASFET<VTO--2, VBI-1.23, RG-0.83, ALPHA-2.3, BETA-3.1E-5 + LAMBDA-0.055, CGSO-0.595FF, CGD-0.595FF, CDS-0.07.91 FF, IS-2.07E-15, + RD-1170, RS-705, TAU-0.71PS> .MODEL RSAG12 GASFET<VTO--2, VBI-1.23, RG-0.83, ALPHA-2.3, BETA-3.1E-5 + LAMBDA-0.055, CGSO-0.595FF, CGD-0.595FF, CDS-0.079IFF, IS-2.07E-15, + RD-1170, RS-1170, TAO-0.71PS) • .MODEL TD4 D<IS-.312E-12 , RS-1745, N - 1 .1, TT-.59PS, CJO-8.02E-15. + VJ-0.72, EG-1.42, BV-8, IBV-1E-3) • •Independent Sources VDD 2 0 4.5 VSS 1 0 - 3 • Sine wave Tracking Open Switch * VRFIN 23 0 SIN(-0.6 0.2 1GHZ) VSGB 25 0 -0.3 VGGB 24 0 -0.3 .TRAN 10PS 1NS .PRINT TRAN V(23) V(20) V(21) .END ISAB RI26R912T3 Tracking with 2.3Tau Aperture • •Cycle Controls and List ing Options .OPTIONS ITL4-1000 ITL5-0 LIMPTS-2000 NOPAGE NOMOD .WIDTH OOT-80 • • • • • • • • • • • • • • I S A B Circuit******* • BSS 9 26 6 R12S 60 BSG2 11 24 10 R12G2 Vt 23 6 O V3 9 10 0 V4 11 20 0 VS 25 26 0 • XAMP1 20 21 1 2 AMP •ISAB Circui t Passive and Parasit ic Components CFIXED 11 0 39FF « • • • • • • • • • • E n d ISAB Circuit******* •Amplifier Subcircuit « .SDBCKT AMP 3 5 12 BIN 4 3 0 RSAG12 67 BFB 4 5 0 RSAG12 23 BLPU 2 4 4 RSAG12 45 BPU 2 4 6 RSAG12 90 D1 6 7 TD4 66 D2 7 8 TD4 66 D3 8 5 TD4 66 BPD 5 1 1 RSAG12 90 .ENDS AMP •Active Element Models • MODEL R12S GASFET(VT0--2, VBI-1.23, RG=0.83, ALPHA-2.3, BETA-3.1E-5 + LAMBDA-0.055, CGSO-0.595FF, CGD-0.595FF, CDS-0.0791FF, IS-2.07E-15. • RD-705, RS-1170, TAU-0.71PS) .MODEL R12G2 GASFET (VTO- - 2 , VBI = 1.23, RG«0.83, ALPHA-2.3, BETA-3. 1E-5 + LAMBDA-0.055, CGSO-0.595FF, CGD-0.595FF, CDS-0.0791FF, IS-2.07E-15, + RD-1170, RS-705, TAU-0.71PS) .MODEL RSAG12 GASFET(VTO--2, VBI-1.23, RG-0.83, ALPHA-2.3, BETA-3.1E-5 • LAMBDA-0.055, CGSO-0.595FF, CGD-0.595FF, CDS-0.0791FF, IS-2.07E-15, + RD-1170. RS-1170, TAU-0.71PS> • .MODEL TD4 D<IS-.312E-12, RS-1745, N-1.1. TT-.59PS. CJO-8.02E-15. + VJ-0.72, EG-1.42, BV-8. IBV-1E-3) • •Independent Sources VDD 2 0 4.5 VSS 1 0 -3 • •Sine wave Tracking at Sampling Aperture 2.3Tau • VRFIN 23 0 SIN(-0.6 0.2 1GHZ) VSIN 25 0 POLSE<-2.9 -.3 5PS 5PS 5PS 57.5PS 100PS) VGGB 24 0 -0.3 .TRAN IPS INS .PRINT TRAN V<26) V(23) V(20) V(21) • .END ISAB RI26R912T3 Tracking with Tau Aperture • •Cycle Controls and Lis t ing Options .OPTIONS ITL4-1000 ITL5-0 LIMPTS-2000 NOPAGE NOMOD .WIDTH OUT-80 * • • • • • • • • • » * * * I S A B C i r c u i t » » » » » » » • BSS 9 26 6 R12S 60 BSG2 11 24 10 R12G2 V1 23 6 0 V3 9 10 0 V4 11 20 0 V5 25 26 0 • XAMP1 20 21 1 2 AMP •ISAB Circui t Passive and Parasit ic Components CFIXED 11 0 39FF * • • • • • • • • • • E n d ISAB Circuit******* •Amplifier Subcircuit * . SUBCKT AMP 3 5 12 BIN 4 3 0 RSAG12 67 BFB 4 5 0 RSAG12 23 BLPU 2 4 4 RSAG12 45 BPU 2 4 6 RSAG12 90 DI 6 7 TD4 66 D2 7 8 TD4 66 D3 8 5 TD4 66 BPD 5 1 1 RSAG12 90 .ENDS AMP * •Active Element Models .MODEL R12S GASFET(VTO--2, VBI-1.23, RG-0.83, ALPHA-2.3, BETA-3.1E-5 + LAMBDA-0.055, CGSO-0.595FF, CGD-0.595FF, CDS-0.0791FF, IS-2.07E-15, + RD-705, RS-1170, TAU-0.71PS) .MODEL R12G2 GASFET(VTO--2, VBI-1.23, RG-0.83, ALPHA-2.3, BETA-3.1E-5 + LAMBDA-0.055, CGSO-0.595FF, CGD-0.595FF, CDS-0.0791FF, IS-2.07E-15, + RD-1170, RS-705, TAO-0.71PS) .MODEL RSAG12 GASFET<VTO--2, VBI-1.23, RG-0.83, ALPHA-2.3, BETA-3.1E-5 + LAMBDA-0.055, CGSO-0.595FF, CGD-0.595FF, CDS-0.0791FF, IS-2.07E-15, * RD-1170, RS-1170, TAU-0.71PS) • .MODEL TD4 D<IS-.312E-12, RS-1745, N-1.1, TT-.59PS, CJO-8.02E-15, + VJ-0.72, EG-1.42, BV-8, IBV-1E-3) « •Independent Sources VDD 2 0 4.5 VSS 1 0 -3 • •Sine Nave Tracking at Sampling Aperture Tau • VRFIN 23 0 SIN<-0.6 0.2 1GHZ) VSIN 25 0 PULSE<-2.9 -.3 5PS 5PS 5PS 25PS 100PS) VGGB 4 0 -0.3 .TRAN 1PS INS .PRINT TRAN V(25) V<23> V(20> V<21> .END ISAB RH6R912T3 Time Constant Determination • •Cycle Controls and List ing Options .OPTIONS ITL4-1000 ITL5-0 LIMPTS-2000 NOPAGE NOMOD •WIDTH OUT-80 • • • • • • • • • • • • • • I S A B Circuit******* • BSS 11 26 6 RSAG12 60 VI 23 6 0 V4 11 20 0 V5 25 26 0 • XAMP1 20 21 1 2 AMP •ISAB Circu i t Passive and Parasi t ic Components CFIXED 11 0 152FF • • • • • • • • • • • E n d ISAB Circuit******* •Amplifier Subcircuit • .SUBCKT AMP 3 5 12 BIN 4 3 0 RSAG12 67 BFB 4 5 0 RSAG12 23 BLPU 2 4 4 RSAG12 45 BPU 2 4 6 RSAG12 90 Dl 6 7 TD4 66 D2 7 8 TD4 66 D3 8 5 TD4 66 BPD 5 1 1 RSAG12 90 .ENDS AMP * •Active Element Models .MODEL RSAG12 GASFET(VTO--2, VBI-1.23, RG-0.83, ALPHA-2.3, BETA-3.1E-5 + LAMBDA-0.055, CGSO-0.595FF, CGD-0.595FF, CDS-0.0791FF, IS-2.07E-15, + RD-1170. RS-1170, TAU-0.71PS) * .MODEL TD4 D(IS-.312E-12, RS-1745, N-1.1, TT-.59PS. CJO-8.02E-15. + VJ-0.72, EG-1.42, BV-8, IBV-1E-3) • •Independent Sources VDD 2 0 4.5 VSS 1 0 - 3 * •Input Time Constant Determination VSGB 25 0 -0.3 VRFIN 23 0 -0.6 PWUOPS -.8 0. IPS -.4 100PS -0.4 100. 1PS -0.8 200PS -0. .TRAN 2PS 200PS .PRINT TRAN V(6) V<20> .END ISAB RH6R912T3 Pulse Feedthrough • •Cycle Controls and List ing Options .OPTIONS ITL4=1000 ITL5-0 LIMPTS-2000 NOPAGE NOMOD .WIDTH OUT«80 • • • • •«******«*ISAB Circuit******* * BSS 11 26 6 RSAG12 60 VI 23 6 0 V4 11 20 0 V5 25 26 0 • XAMP1 20 21 1 2 AMP •ISAB Circui t Passive and Parasit ic Components CFIXED 11 0 152FF CRFPAD 23 0 20FF CGPAD 24 0 2OFF LRFIN 13 23 0.16NH LGIN 14 24 0.16NH RRFIN 3 13 50 RGIN 4 14 50 • • • • • • • « « * * E n d I S A B Circuit******* •Amplifier Subcircuit • .SUBCKT AMP 3 5 12 BIN 4 3 0 RSAG12 67 BFB 4 5 0 RSAG12 23 BLPU 2 4 4 RSAG12 45 BPU 2 4 6 RSAG12 90 D1 6 7 TD4 66 D2 7 8 TD4 66 D3 8 5 TD4 66 BPD 5 1 1 RSAG12 90 .ENDS AMP * •Active Element Models .MODEL RSAG12 GASFET(VTO=-2, VBI=1.23, RG=0.83, ALPHA«2.3, B E T A « 3 . 1 E " 5 + LAMBDA=0.055, CGS0=0.595FF, CGD-0.595FF, CDS=0.0791FF, I S » 2 . 0 7 E - 1 5 , • RD=1170, RS=M70, TAU=0.71PS) * .MODEL TD4 D< IS=.312E-12, RS=1745, N=1.1, TT=.59PS, CJO=8.02E-15, + VJ=0.72, EG=1.42, BV=8, IBV=1E-3) * •Independent Sources VDD 2 0 4.5 VSS 1 0 - 3 * •Pulse Feedthrough at Vbias * VSIN 25 0 PULSE<-2.9 -.3 5PS 5PS 5PS 25PS 200PS) VRFB 3 0 -0.6 .TRAN 0. IPS 50PS .PRINT TRAN V<26) V<23) V<20) . END ISAB RI16R912T3 Off Isolation * •Cycle Controls and List ing Options .OPTIONS ITL4-1000 ITL5-0 LIMPTS-2000 NOPAGE NOMOD .WIDTH OUT-80 • • • • • • • • • • • • • • I S A B Circuit******* • BSS 11 26 6 RSAG12 60 VI 23 6 0 V4 11 20 0 V5 25 26 0 • XAMP1 20 21 12 AMP •ISAB Circui t Passive and Parasit ic Components CFIXED 11 0 152FF * • • • • • • • • • • E n d ISAB Circuit******* •Amplifier Subcircuit • .SUBCKT AMP 3 5 1 2 BIN 4 3 0 RSAG12 67 BFB 4 5 0 RSAG12 23 BLPU 2 4 4 RSAG12 45 BPU 2 4 6 RSAG12 90 D1 6 7 TD4 66 D2 7 8 TD4 66 D3 8 5 TD4 66 BPD 5 1 1 RSAG12 90 .ENDS AMP • •Active Element Models • MODEL RSAG12 GASFET<VTO--2, VBI-1.23, RG-0.83, ALPHA-2.3, BETA-3.1E- + LAMBDA-0.055, CGSO-0.595FF, CGD-0.595FF, CDS-0.079IFF, IS-2.07E-15, + RD-1170, RS-1170, TAU=0.71PS> • .MODEL TD4 D<IS-.312E-12, RS-1745, N-1.1, TT-.59PS, CJO-8.02E-15, + VJ-0.72, EG-1.42, BV-8, IBV-1E-3) • •Independent Sources VDD 2 0 4.5 VSS 1 0 -3 * •Off Isolation with 10 GHz Sine RF Input • RSHUNT 23 20 5M VRFIN 23 0 SIN<-0.6 0.2 10GHZ) VSGB 25 0 -2 .9 .TRAN 2PS 100PS .PRINT TRAN V(23> V(20) V(21) .END ISAB RI16R912T3 Open Switch Tracking * •Cycle Controls and List ing Options .OPTIONS ITL4-1000 ITL5-0 LIMPTS-2000 NOPAGE NOMOD .WIDTH OUT-80 • • • • • • • • • • • • • • I S A B Circuit******* « BSS 11 26 6 RSAG12 60 VI 23 6 0 V4 11 20 0 V5 25 26 0 • XAMP1 20 21 1 2 AMP •ISAB Circui t Passive and Parasit ic Components CFIXED 11 0 152FF 145 •••*******End ISAB Circuit******* •Amplifier Subcircuit • .SUBCKT AMP 3 5 1 2 BIN 4 3 0 RSAG12 67 BFB 4 5 0 RSAG12 23 BLPU 2 4 4 RSAG12 45 BPU 2 4 6 RSAG12 90 D1 6 7 TD4 66 02 7 8 TD4 66 D3 8 5 T04 66 BPD 5 1 1 RSAG12 90 •ENDS AMP • •Active Element Models • MODEL RSAG12 GASFET<VTO=-2, VBI-1.23, RG-0.83, ALPHA-2.3, BETA-3.1E-5 • LAMBDA-0.055, CGSO-0.595FF, CGD-0.595FF, CDS-0.0791FF, IS-2.07E-15, • RD-1170. RS-1170. TAU-0.71PS) * •MODEL TD4 D<IS-.312E-12, RS-1745, N-1.1, TT-.59PS, CJO-8.02E-15, + VJ-0.72, EG-1.42, BV-8, IBV-1E-3) * •Independent Sources VDD 2 0 4.5 VSS 1 0 -3 • Sine wave Tracking Open Switch • VRFIN 23 0 SIN(-0.6 0.2 1GHZ) VSGB 25 0 -0.3 .TRAN 10PS INS .PRINT TRAN V<23) V<20) V(21> .END ISAB RI16R912T3 Tracking with 2.3Tau Aperture • •Cycle Controls and List ing Options •OPTIONS ITL4-1000 ITL5-0 LIMPTS-2000 NOPAGE NOMOD .WIDTH OUT-80 • •«««*»******»ISAB Circuit******* * BSS 11 26 6 RSAG12 60 V1 23 6 0 V4 11 20 0 V5 25 26 0 * XAMP1 20 21 1 2 AMP •ISAB Circui t Passive and Parasit ic Components CFIXED 11 0 152FF * •*«******«End ISAB Circuit******* •Amplifier Subcircuit * .SUBCKT AMP 3 5 12 BIN 4 3 0 RSAG12 67 BFB 4 5 0 RSAG12 23 BLPU 2 4 4 RSAG12 45 BPU 2 4 6 RSAG12 90 D1 6 7 TD4 66 D2 7 8 TD4 66 S3 8 5 TD4 66 BPD 5 1 1 RSAG12 90 .ENDS AMP • •Active Element Models -MODEL RSAG12 GASFET(VTO=-2, VBI-1.23, RG=0.83, ALPHA-2.3, BETA-3.1E-5 + LAMBDA-0.055, CGSO-0.595FF, CGD-0.595FF, CDS-0.079IFF. IS-2.07E-15. + RD-1170, RS-1170, TAU-0.71PS) • .MODEL TD4 D(IS-.312E-12, RS-1745, N-1.1, TT-.59PS, CJO-8.02E-15, + VJ-0.72, EG-1.42, BV-8. IBV-1E-3) • •Independent Sources VDD 2 0 4.5 VSS 1 0 - 3 • •Sine wave Tracking at Sampling Aperture 2.3Tau * VRFIN 23 0 SIN(-0.6 0.2 1GHZ) VSIN 25 0 POLSE<-2.9 -.3 5PS 5PS 5PS 53PS 100PS) .TRAN 1PS 1NS .PRINT TRAN V(26) V<23) V(20> V<21> . END ISAB RI16R912T3 Tracking with Tau Aperture * •Cycle Controls and List ing Options -OPTIONS ITL4-1000 ITL5-0 LIMPTS-2000 NOPAGE NOMOD .WIDTH OUT-80 • • • • • • • • • • • • • • I S A B Circuit******* • BSS 11 26 6 RSAG12 60 VI 23 ( 0 V4 11 20 0 V5 25 26 0 • SAMP1 20 21 1 2 AMP •ISAB Circui t Passive and Parasit ic Components CFIXED 11 0 152FF • • • • • • • • • • • E n d ISAB Circuit******* •Amplifier Subcircuit • .SUBCKT AMP 3 5 12 BIN 4 3 0 RSAG12 67 BFB 4 5 0 RSAG12 23 BLPU 2 4 4 RSAG12 45 BPU 2 4 6 RSAG12 90 D1 6 7 TD4 66 D2 7 8 TD4 66 D3 8 5 TD4 66 BPD 5 1 1 RSAG12 90 .ENDS AMP • •Active Element Models .MODEL RSAG12 GASFET(VTO--2, VBI-1.23, RG-0.83, ALPHA-2.3, BETA-3.1E-5 + LAMBDA-0.055, CGSO-0.595FF, CGD-0.595FF, CDS-0.0791FF, IS-2.07E-15, + RD-1170, RS-1170, TAU-0.71PS) * .MODEL TD4 D(IS-.312E-12. RS-1745, N-1.1, TT-.59PS, CJO-8-02E-15, + VJ-0.72, EG-1.42, BV-8, IBV-1E-3) • •Independent Sources VDD 2 0 4.5 VSS 1 0 -3 • •Sine wave Tracking at Sampling Aperture Tau • VRFIN 23 0 SIN<-0.6 0.2 1GHZ) VSIN 25 0 PULSE(-2.9 -.3 5PS 5PS 5PS 23PS 100PS) 147 .TRAN IPS 1NS .PRINT TRAN V(26> V(23> V<20) V(21> .END ISAB RI16R922T3 Time Constant Determination • •Cycle Controls and Lis t ing Options •OPTIONS ITL4-1000 ITL5-0 LIMPTS-2000 NOPAGE NOMOD .WIDTH OUT-80 * «**»»*«******ISAB Circuit******* • BSS 11 26 6 RSAG22 60 VI 23 6 0 V4 11 20 0 V5 25 26 0 * XAMP1 20 21 1 2 AMP •ISAB Circui t Passive and Parasit ic Components CFIXED 11 0 74FF * *****«*«»*End ISAB Circuit******* •Amplifier Subcircuit • .SUBCKT AMP 3 5 1 2 BIN 4 3 0 RSAG22 67 BFB 4 5 0 RSAG22 23 BLPU 2 4 4 RSAG22 45 BPU 2 4 6 RSAG22 90 D1 6 7 TD4 40 D2 7 8 TD4 40 D3 8 5 TD4 40 BPD 5 1 1 RSAG22 90 .ENDS AMP • •Active Element Models .MODEL RSAG22 GASFET(VTO--2, VBI-1.23, RG-0.5, ALPHA-2.3, BETA-2.61E-5 + LAMBDA-0.055, CGS0-1.19FF, CGD-1.19FF, CDS-0.096FF, IS-4.13E-15, + RD-1555, RS-1555, TAU-2.86PS) * .MODEL TD4 D(IS-.312E-12, RS-1745, N-1.1, TT-.59PS, CJO-8.02E-15, + VJ-0.72, EG-1.42, BV-8, IBV-1E-3) • •Independent Sources VDD 2 0 4.5 VSS 1 0 -3 • •Input Time Constant Determination * VSGB 25 0 -0.35 VRFIN 23 0 -0.65 PWL(0PS -.8 0.1PS -.4 100PS -0.4 100.1PS -0.8 200PS -0.8) .TRAN 2PS 200PS .PRINT TRAN V(6> V(20) .END ISAB RH6R922T3 Pulse Feedthrough * •Cycle Controls and List ing Options .OPTIONS ITL4-1000 ITL5-0 LIMPTS-2000 NOPAGE NOMOD .WIDTH OUT-80 • •**»**»**««**ISAB Circuit******* • BSS 11 26 6 RSAG22 60 V1 23 6 0 V4 11 20 0 V5 25 26 0 XAMP1 20 21 1 2 AMP •ISAB Circui t Passive and Parasit ic Components CFIXED 11 0 74FF CRFPAD 23 0 20FF CGPAD 24 0 2OFF LRFIN 13 23 0.16NH LGIN 14 24 0.16NH RRFIN 3 13 50 RGIN 4 14 50 • •o********End ISAB Circuit******* •Amplifier Subcircuit • .SUBCKT AMP 3 5 1 2 BIN 4 3 0 RSAG22 67 BFB 4 5 0 RSAG22 23 BLPU 2 4 4 RSAG22 45 BPU 2 4 6 RSAG22 90 DI 6 7 TD4 40 D2 7 8 TD4 40 D3 8 5 TD4 40 BPD 5 1 1 RSAG22 90 . ENDS AMP • •Active Element Models .MODEL RSAG22 GASFET(VTO--2, VBI-1.23, RG-0.5, ALPHA-2.3, BETA-2.61E-5 + LAMBDA-0.055, CGS0-1.19FF, CGD-1.19FF, CDS-0.096FF, IS-4.13E-15, • RD-1555, RS-1555, TAU-2.86PS) • .MODEL TD4 D(IS-.312E-12, RS-174S, N-1.1, TT-.59PS, CJO-8.02E-15. + VJ-0.72, EG-1.42, BV-8, IBV-1E-3) * •Independent Sources VDD 2 0 4.5 VSS 1 0 -3 • •Pulse Feedthrough at Vbias • VSIN 25 0 PULSE<-2.95 -.35 5PS 5PS 5PS 25PS 200PS) VRFB 3 0 -0.65 .TRAN 0.IPS 50PS .PRINT TRAN V<26> V(23> V(20> . END ISAB RI16R922T3 Off Isolation » •Cycle Controls and List ing Options -OPTIONS ITL4-1000 ITL5-0 LIMPTS-2000 NOPAGE NOMOD .WIDTH OUT-80 * • • • • • • • • • • • • • I S A B Circuit******* * BSS 11 26 6 RSAG22 60 VI 23 6 0 V4 11 20 0 VS 25 26 0 * XAMP1 20 21 1 2 AMP •ISAB Circui t Passive and Parasit ic Components CFIXED 11 0 74FF * • • • • • • • • • • E n d ISAB Circuit******* •Amplifier Subcircuit • .SUBCKT AMP 3 5 1 2 BIN 4 3 0 RSAG22 67 BFB 4 5 0 RSAG22 23 BLPU 2 4 4 RSAG22 45 BPU 2 4 6 RSAG22 90 Dl 6 7 TD4 40 D2 7 8 TD4 40 D3 8 5 TD4 40 BPD 5 1 1 RSAG22 90 •ENDS AMP • •Active Element Models .MODEL RSAG22 GASFET(VTO=-2, VBI=1.23, RG=0.5, ALPHA-2.3, BETA=2.61E-5 + LAMBDA=0.055, CGS0=1.19FF, CGD=1.19FF, CDS=0.096FF, IS=4.13E-15, + RD*1555, RS=1555, TAU=2.86PS) • .MODEL TD4 D( IS-.312E-12, RS=1745. N-1.1, TT-.59PS, CJO-8.02E-15, + VJ-0.72, EG=1.42, BV-8, IBV-1E-3) • •Independent Sources VDD 2 0 4.5 VSS 1 0 - 3 • •Off Isolation with 10 GHz Sine RF Input • RSHUNT 23 20 10M VRFIN 23 0 SIN("0.65 0.2 10GHZ) VSGB 25 0 -2.95 .TRAN 2PS 100PS .PRINT TRAN V(23) V(20> V(21) . END ISAB RH6R922T3 Open Switch Tracking • •Cycle Controls and Lis t ing Options .OPTIONS ITL4-1000 ITL5-0 LIMPTS-2000 NOPAGE NOMOD .WIDTH OUT-80 « • • • • • • • • • • • • • I S A B Circuit******* • BSS 11 26 6 RSAG22 60 VI 23 6 0 V i 11 20 0 V5 25 26 0 • XAMP1 20 21 12 AMP •ISAB Circui t Passive and Parasit ic Components CFIXED 11 0 74FF * • • • • • • • • • • E n d ISAB Circuit******* •Amplifier Subcircuit • -SUBCKT AMP 3 5 12 BIN 4 3 0 RSAG22 67 BFB 4 5 0 RSAG22 23 BLPU 2 4 4 RSAG22 45 BPU 2 4 6 RSAG22 90 D1 6 7 TD4 40 D2 7 8 TD4 40 D3 8 5 TD4 40 BPD 5 1 1 RSAG22 90 .ENDS AMP * •Active Element Models .MODEL RSAG22 GASFET<VTO=-2, VBI=1.23, RG-0.5, ALPHA=2.3, BETA=2.61E"5 + LAMBDA=0.055, CGS0=1-19FF, CGD-1-19FF, CDS=0.096FF, IS=4.13E-15, + RD=1555, RS=1555, TAU=2.86PS) 150 •MODEL TD4 D<IS=.312E-12. RS=1745, N=1.1, TT*.59PS, GJO=8.02E-15. + VJ=0.72, EG«1.42, BV=8, IBV«1E-3) « •Independent Sources VDD 2 0 4.5 VSS 1 0 -3 * Sine wave Tracking Open Switch • VRFIN 23 0 SIN(-0.65 0.2 1GHZ) VSGB 25 0 -0.35 .TRAN 10PS 1NS .PRINT TRAN V<23) V(20) V(21> • END ISAB RH6R922T3 Tracking with 2.3Tau Aperture • •Cycle Controls and Lis t ing Options .OPTIONS ITL4«1000 ITL5=0 LIMPTS=2000 NOPAGE NOMOD .WIDTH OUT=80 • • • • • • • • • • • • • • I S A B Circuit******* * BSS 11 26 6 RSAG22 60 VI 23 6 0 V4 11 20 0 V5 25 26 0 • XAMP1 20 21 1 2 AMP •ISAB Circu i t Passive and Parasit ic Components CFIXED 11 0 74FF * • • • • • • • • • • E n d ISAB Circuit******* •Amplifier Subcircuit • .SUBCKT AMP 3 5 12 BIN 4 3 0 RSAG22 67 BFB 4 5 0 RSAG22 23 BLPU 2 4 4 RSAG22 45 BPU 2 4 6 RSAG22 90 D1 6 7 TD4 40 D2 7 8 TD4 40 D3 8 5 TD4 40 BPD 5 1 1 RSAG22 90 .ENDS AMP * •Active Element Models .MODEL RSAG22 GASFET(VTO=-2, VBI=1.23, RG=0.83, ALPHA=2.3, BETA=3.1E"5 + LAMBDA=0.055, CGS0=0.595FF, CGD=0.595FF, CDS=0.0791FF, IS=2.07E-15, + RD=1170, RS=1170, TAU=0.71PS) • .MODEL TD4 D(IS=.312E-12, RS=1745, N=1.1, TT=.59PS, CJO=8.02E-15, + V J » 0 . 7 2 , EG=1.42, BV=8. IBV=1E-3) * •Independent Sources VDD 2 0 4.5 VSS 1 0 -3 * •Sine Wave Tracking at Sampling Aperture 2.3Tau * VRFIN 23 0 SIN(-0.65 0.2 1GHZ) VSIN 25 0 PULSE(-2.95 -.35 5PS 5PS 5PS 53PS 100PS) .TRAN IPS INS .PRINT TRAN V(25) V(23) V<20> V(21> • END 151 ISAB RI16R922T3 Tracking with Tau Aperture » •Cycle Controls and List ing Options .OPTIONS ITL4-1000 ITL5-0 LIMPTS=2000 NOPAGE NOMOD .WIDTH OUT-80 • •***********«ISAB Circuit******* • BSS 11 26 6 RSAG22 60 VI 23 6 0 V4 11 20 0 V5 25 26 0 • XAMP1 20 21 1 2 AMP •ISAB Circui t Passive and Parasit ic Components CFIXED 11 0 74FF • ******«**»End ISAB Circuit******* •Amplifier Subcircuit • .SUBCKT AMP 3 5 12 BIN 4 3 0 RSAG22 67 BFB 4 5 0 RSAG22 23 BLPU 2 4 4 RSAG22 45 BPU 2 4 6 RSAG22 90 DI 6 7 TD4 40 D2 7 8 TD4 40 D3 8 5 TD4 40 BPD 5 1 1 RSAG22 90 .ENDS AMP * •Active Element Models .MODEL RSAG22 GASFET(VTO«-2, VBI-1.23, RG-0.25, ALPHA-2.3, BETA-2.61E-5 + LAMBDA-0.055, CGS0-1.19FF, CGD-1.19FF, CDS-0.096FF, IS-4.13E-15, + RD-1555, RS-1555, TAU-2.86PS) • .MODEL TD4 D< IS-.312E"12, RS-1745, N-1.1. TT-.59PS, CJO-8.02E-16, • VJ-0.72, EG-1.42, BV-8, IBV-1E-3) * •Independent Sources VDD 2 0 4.5 VSS 1 0 -3 • •Sine wave Tracking at Sampling Aperture Tau « VRFIN 23 0 SIN(-0.65 0.2 1GHZ) VSIN 25 0 PULSE(-2.95 -.35 5PS 5PS 5PS 23PS 100PS) .TRAN 1PS 1NS .PRINT TRAN V(26) V(23) V(20) V<21) . END ISAB RI36R912T3 Pulse Feedthrough at vbias * •Cycle Controls and List ing Options .OPTIONS ITL4-1000 ITL5-0 LIMPTS-2000 NOPAGE NOMOD .WIDTH OUT-80 • ••••*********ISAB Circuit******* * BSG1 7 24 6 R12G1 60 BSS 9 26 8 R12S 60 BSG2 11 24 10 R12G2 60 V1 23 6 0 V2 7 8 0 V3 9 10 0 V4 11 20 0 V5 25 26 0 • XAMP1 20 21 1 2 AMP •ISAB Circuit Passive and Parasit ic Components CFIXED 11 0 9FF IC--0.6 CRFPAD 23 0 2OFF CGPAD 24 0 20FF LRFIN 13 23 0.16NH LGIN 14 24 0.16NH RRFIN 3 13 50 RGIN 4 14 50 • • • • • • • • • • • E n d ISAB Circuit******* •Amplifier Subcircuit • .SUBCKT AMP 3 5 1 2 BIN 4 3 0 RSAG12 67 BFB 4 5 0 RSAG12 23 BLPU 2 4 4 RSAG12 45 BPU 2 4 6 RSAG12 90 Dl 6 7 TD4 66 D2 7 8 TD4 66 D3 8 5 TD4 66 BPD 5 1 1 RSAG12 90 .ENDS AMP « •Active Element Models .MODEL RSAG12 GASFET(VTO--2, VBI-1.23. RG-0.83, ALPHA-2.3, BETA-3.1E-5 + LAMBDA-0.055. CGSO-0.S95FF, CGD-0.S95FF, CDS-0.0791FF. IS-2 .07E -15 , + RD-1170, RS-1170, TAU-0.71PS) .MODEL R12G1 GASFET(VTO--2, VBI-1.23, RG-0.83, ALPHA-2.3, BETA-3.1E-5 • LAMBDA-0.055, CGSO-0.595FF, CGD-0.595FF, CDS-0.0791FF, IS-2.07E-15, + RD-705, RS-1170, TAU-0.71PS) .MODEL R12S GASFET(VTO--2, VBI-1.23, RG-0.83, ALPHA-2.3, BETA-3.1E-5 + LAMBDA-0.055, CGSO-0.595FF, CGD-0.595FF, CDS-0.0791FF, IS-2.07E-15, • RD-705, RS-705, TAU-0.71PS) .MODEL R12G2 GASFET(VTO--2, VBI-1.23, RG-0.83, ALPHA-2.3, BETA-3.1E-5 • LAMBDA-0.055, CGSO-0.595FF, CGD-0.595FF, CDS-0.0791FF, IS-2.07E-15, + RD-1170. RS-705, TAU-0.71PS) • .MODEL TD4 D(IS-.312E-12, RS-1745, N-1.1, TT-.59PS, CJO-8.02E-15, + VJ-0.72, EG-1.42, BV-8, IBV-1E-3> • •Independent Sources VDD 2 0 4.5 VSS 1 0 -3 • •Pulse Feedthrough at vbias • VSIN 25 0 PULSE<-2.9 -.3 5PS 5PS 5PS 25PS 200PS> VGGB 4 0 -0.6 VRFB 3 0 -0.6 .TRAN 0.25PS 50PS UIC .PRINT TRAN V(26> V(23) V(20> • END ISAB RI36R912T3 Off Isolation at 10GHz * •Cycle Controls and List ing Options .OPTIONS ITL4-1000 ITL5-0 LIMPTS-2000 NOPAGE NOMOD .WIDTH OUT-80 • • • • • • • • • • • • • • I S A B Circuit******* • BSG1 7 24 6 R12G1 60 BSS 9 26 8 R12S 60 BSG2 11 24 10 R12G2 60 V1 23 6 0 V2 7 8 0 V3 9 10 0 V4 11 20 0 V5 25 26 0 * ZAHP1 20 21 1 2 AMP •ISAB Circui t Passive and Parasi t ic Components CFIXED 11 0 9FF • • • • • • • • • • • E n d ISAB Circuit******* •Amplifier Subcircuit • .SUBCKT AMP 3 5 1 2 BIN 4 3 0 RSAG12 67 BFB 4 5 0 RSAG12 23 BLPU 2 4 4 RSAG12 45 BPU 2 4 6 RSAG12 90 Dt 6 7 TD4 66 D2 7 B TD4 66 D3 8 5 TD4 66 BPD 5 1 1 RSAG12 90 •ENDS AMP • •Active Element Models •MODEL RSAG12 GASFET(VTO--2, VBI-1.23, RG-0.83, ALPHA-2.3, BETA-3.1E-5 • LAMBDA-0.055, CGSO-0.595FF, CGD-0.595FF, CDS-0.0791FF, IS-2.07E-15, + RD-1170, RS-1170, TAU-0.71PS) .MODEL R12G1 GASFET(VTO--2, VBI-1.23, RG-0.83, ALPHA-2.3, BETA-3.1E-5 • LAMBDA-0.055, CGSO-0.595FF. CGD-0.595FF, CDS-0.0791FF, IS-2.07E-15, + RD-705. RS-1170, TAU-0.71PS) .MODEL R12S GASFET(VTO--2, VBI-1.23, RG-0.83, ALPHA-2.3, BETA-3.1E-5 + LAMBDA-0.055, CGS0-O.595FF. CGD-0.595FF, CDS-0.079IFF, IS-2.07E-15, + RD-705, RS-705, TAU-0.71PS) .MODEL R12G2 GASFET<VTO=-2, VBI-1.23, RG-0.83, ALPHA-2.3, BETA-3.1E-5 + LAMBDA-0.055, CGS0-0.595FF, CGD-0.595FF, CDS-0.0791FF, IS-2.07E-15, • RD-1170, RS-705, TAU-0.71PS) • .MODEL TD4 D(IS-.312E"12, RS-1745, N-1.1, TT-.59PS, CJO-8.02E-15, + VJ-0.72, EG-1.42, BV-8, IBV-1E-3) • •Independent Sources VDD 2 0 4.5 VSS 1 0 -3 * •Off Isolation with 10 GHz Sine RF Input * RSHUNT 23 20 0.5E8 VRFIN 23 0 SlN(-0.6 0.2 10GHZ) VSGB 25 0 -2.9 VGGB 24 0 -0.3 .TRAN 2PS 100PS .PRINT TRAN V(23> V(20) V(21) .END ISAB RI36R912T3 Open Switch Tracking • •Cycle Controls and List ing Options .OPTIONS ITL4-1000 ITL5-0 LIMPTS-2000 NOPAGE NOMOD .WIDTH OUT-80 * • • • * • • • • * • • » * I S A B Circuit******* « BSG1 7 24 6 R12G1 60 BSS 9 26 8 R12S 60 BSG2 11 24 10 R12G2 60 V1 23 6 0 V2 7 8 0 V3 9 10 0 V4 11 20 0 VS 25 26 0 • XAMP1 20 21 1 2 AMP •ISAB Circui t Passive and Parasit ic Components CFIXED 11 0 9FF • •*««**«***End ISAB Circuit******* •Amplifier Subcircuit « .SUBCKT AMP 3 5 12 BIN 4 3 0 RSAG12 67 BFB 4 5 0 RSAG12 23 BLPU 2 4 4 RSAG12 45 BPU 2 4 6 RSAG12 90 D1 6 7 TD4 66 D2 7 8 TD4 66 D3 8 5 TD4 66 BPD 5 1 1 RSAG12 90 .ENDS AMP • •Active Element Models .MODEL RSAG12 GASFET(VTO--2, VBI=1.23, RG-0.83, ALPHA-2.3, BETA-3.1E-5 + LAMBDA-0.055. CGSO-0.595FF, CGD-0.595FF, CDS-0.0791FF, IS-2.07E-15, + RD-1170, RS-1170, TAU-0.71PS) .MODEL R12G1 GASFET(VTO--2, VBI-1.23, RG-0.83, ALPHA-2.3, BETA-3.1E-5 + LAMBDA-0.055, CGSO-0.595FF, CGD-0.595FF, CDS-0.0791FF, IS-2.07E-15, + RD-705, RS-1170, TAU-0.71PS) .MODEL R12S GASFET(VTO--2, VBI-1.23, RG-0.83, ALPHA-2.3, BETA-3.1E-5 + LAMBDA-0.055, CGSO-0.595FF. CGD-0.595FF, CDS-0.0791FF, IS-2.07E-15, + RD-705, RS-705, TAU-0.71PS) .MODEL R12G2 GASFET(VTO--2, VBI-1.23, RG-0.83, ALPHA-2.3, BETA-3.1E-5 + LAMBDA-0.055, CGSO-0.595FF, CGD-0.595FF, CDS-0.0791FF, IS-2.07E-15, •RD-1170, RS-705, TAU-0.71PS) * .MODEL TD4 D<IS-.312E-12, RS-1745, N-1.1, TT-.59PS, CJO-8.02E-15, + VJ-0.72, EG-1.42, BV-8, IBV-1E-3) • •Independent Sources VDD 2 0 4.5 VSS 1 0 -3 * •Sine Have Tracking Open Switch • VRFIN 23 0 SIN<-0.6 0.2 1GHZ) VSGB 25 0 -0.3 VGGB 24 0 -0.3 .TRAN 10PS INS .PRINT TRAN V<23> V(20> V(21) .END ISAB RI36R912T3 Tracking at 100PS Aperture * •Cycle Controls and List ing Options .OPTIONS ITL4-1000 ITL5-0 LIMPTS-2000 NOPAGE NOMOD .WIDTH OUT-80 * * * * « * * « * * * * « * I S A B Circuit******* « BSG1 7 24 6 R12G1 60 BSS 9 26 8 R12S 60 BSG2 11 24 10 R12G2 60 VI 23 6 0 V2 7 8 0 V3 9 10 0 V4 11 20 0 V5 25 26 0 • XAMP1 20 21 1 2 AMP •ISAB Circui t Passive and Parasit ic Components CFIXED 11 0 9FF IC--0.6 • • • • • • • • • • • E n d ISAB C i r c u i t * » » » » » » •Amplifier Subcircuit • .SUBCKT AMP 3 5 12 BIN 4 3 0 RSAG12 67 BFB 4 5 0 RSAG12 23 BLPU 2 4 4 RSAG12 45 BPU 2 4 6 RSAG12 90 Dl 6 7 TD4 66 D2 7 8 TD4 66 D3 8 5 TO4 66 BPD 5 1 i RSAG12 90 .ENDS AMP • •Active Element Models .MODEL RSAG12 GASFET<VTO--2, VBI-1.23, RG-0.83, ALPHA-2.3, BETA-3.1E-5 + LAMBDA-0.055, CGSO-0.595FF, CGD-0.595FF, CDS-0.0791FF, IS-2.07E-15, + RD-1170, RS-1170, TAU-0.71PS) .MODEL R12G1 GASFET(VTO--2, VBI-1.23, RG-0.83, ALPHA-2.3, BETA-3.1E-5 • LAMBDA-0.055, CGSO-0.59SFF, CGD-0.595FF, CDS-0.0791FF, IS-2.07E-15, + RD-705, RS-1170, TAU-0.71PS) .MODEL R12S GASFET(VTO--2, VBI-1.23, RG-0.83, ALPHA-2.3, BETA-3.1E-5 + LAMBDA-0.055, CGSO-0.595FF, CGD-0.595FF, CDS-0.0791FF, IS-2.07E-15, + RD-705. RS-705, TAU-0.71PS) .MODEL R12G2 GASFET(VTO--2, VBI-1.23, RG-0.83, ALPHA-2.3, BETA-3.1E-5 + LAMBDA-0.055, CGSO-0.595FF, CGD-0.595FF, CDS-0.079IFF, IS-2.07E-15, • RD-1170, RS-705, TAU-0.71PS) • .MODEL TD4 D<IS-.312E-12, RS-1745, N-1.1, TT-.59PS, CJO-8.02E-15, • VJ-0.72, EG-1.42, BV-8, IBV-1E-3) • •Independent Sources VDD 2 0 4.5 VSS 1 0 -3 • •Sine Have Tracking at Sampling Aperture • VRFIN 23 0 SIN<-0.6 0.2 250MEG> VSIN 25 0 PULSE<-2.9 -.3 5PS 5PS 5PS 100PS 410PS) VGGB 24 0 -0.3 .TRAN 10PS 4NS UIC .PRINT TRAN V<26) V<23) V<20) V<21> .END ISAB RI36R912T3 Tracking at 25PS Aperture • •Cycle Controls and Lis t ing Options .OPTIONS ITL4-1000 ITL5-0 LIMPTS-2000 NOPAGE NOMOD .WIDTH OUT-80 • • * * • • • • • • * * • • I S A B Circuit******* * BSG1 7 24 6 R12G1 60 BSS 9 26 8 R12S 60 BSG2 11 24 10 R12G2 60 V1 23 6 0 V2 7 8 0 V3 9 10 0 V4 11 20 0 V5 25 26 0 • XAMP1 20 21 1 2 AMP •ISAB Circui t Passive and Parasit ic Components CFIXED 11 0 9FF IC--0.6 « • • • • • • • • • • E n d ISAB Circuit******* •Amplifier Subcircuit • .SUBCKT AMP 3 5 12 BIN 4 3 0 RSAG12 67 BFB 4 5 0 RSAG12 23 BLPU 2 4 4 RSAG12 45 BPU 2 4 6 RSAG12 90 D1 6 7 TD4 66 D2 7 8 TD4 66 D3 8 5 TD4 66 BPD 5 1 1 RSAG12 90 •ENDS AMP • •Active Element Models • MODEL RSAG12 GASFET(VTO--2, VBI-1.23, RG-0.83, ALPHA-2.3, BETA-3.1E-5 + LAMBDA-0.055, CGSO-0.595FF, CGD-0.595FF, CDS-0.0791FF, IS-2.07E-15, + RD-1170, RS-1170, TAU-0.71PS) .MODEL R12G1 GASFET(VTO--2, VBI-1.23, RG-0.83, ALPHA-2.3, BETA-3.1E-5 • LAMBDA-0.055, CGSO-0.595FF, CGD-0.595FF, CDS-0.0791FF, IS-2.07E-15, + RD-705, RS-1170, TAU-0.71PS) .MODEL R12S GASFET(VTO=-2, VBI-1.23, RG-0.83, ALPHA-2.3, BETA-3.1E-5 • LAMBDA-0.055, CGSO-0.595FF, CGD-0.595FF. CDS-0.0791FF, IS-2.07E-15, + RD-705, RS-705, TAU-0.71PS) .MODEL R12G2 GASFET<VTO«-2, VBI-1.23, RG-0.83. ALPHA-2.3, BETA-3.1E-5 + LAMBDA-0.055, CGSO-0.595FF, CGD-0.595FF, CDS-0.0791FF. IS-2.07E-15. • RD-1170, RS-705, TAU-0.71PS) • .MODEL TD4 D<IS-.312E-12, RS-1745, N-1.1, TT-.59PS, CJO-8.02E-15, + VJ-0.72, EG-1.42, BV-8. IBV-1E-3) • •Independent Sources VDD 2 0 4.5 VSS 1 0 -3 • •Sine wave Tracking at Sampling Aperture Tau • VRFIN 23 0 SIN<-0.6 0.2 1GHZ) VSIN 25 0 PULSE(-2.9 -.3 5PS 5PS 5PS 25PS HOPS) VGGB 24 0 -0.3 .TRAN 2.5PS INS UIC .PRINT TRAN V(26) V(23) V(20> V<21> .END ISAB RI26R912T3 Pulse Feedthrough * •Cycle Controls and List ing Options .OPTIONS ITL4-1000 ITL5-0 LIMPTS-2000 NOPAGE NOMOD .WIDTH OUT-80 • • • • • • • • • • • • • • I S A B Circuit******* « BSS 9 26 6 R12S 60 BSG2 11 24 10 R12G2 60 VI 23 6 0 V3 9 10 0 V4 11 20 0 V5 25 26 0 • XAMP1 20 21 1 2 AMP •ISAB Circu i t Passive and Parasit ic Components CFIXED 11 0 39FF IC--0.6 CRFPAD 23 0 20FF LRFIN 13 23 0.16NH RRFIN 3 13 50 • • • • • • • • • • • E n d ISAB Circuit******* •Amplifier Subcircuit • .SUBCKT AMP 3 5 12 BIN 4 3 0 RSAG12 67 BFB 4 5 0 RSAG12 23 BLPU 2 4 4 RSAG12 45 BPU 2 4 6 RSAG12 90 D1 6 7 TD4 66 D2 7 8 TD4 66 D3 8 5 TD4 66 BPD 5 1 1 RSAG12 90 .ENDS AMP • •Active Element Models .MODEL R12S GAS FET(VTO--2, VBI-1.23, RG-0.83, ALPHA-2.3, BETA-3.1E-5 • LAMBDA-0.055, CGSO-0.595FF, CGD-0.595FF, CDS-0.079IFF, IS-2.07E-15, • RD-705, RS-1170, TAU-0.71PS) .MODEL R12G2 GASFET(VTO--2, VBI-1.23, RG-0.83, ALPHA-2.3, BETA-3.IE-5 + LAMBDA-0.055, CGSO-0.595FF, CGD-0.595FF, CDS-0.0791FF, IS-2.07E-15, + RD-1170, RS-705, TAU-0.71PS) .MODEL RSAG12 GASFET(VTO--2, VBI-1.23, RG-0.83, ALPHA-2.3, BETA-3.1E-S + LAMBDA-0.055, CGSO-0.595FF, CGD-0.595FF, CDS-0.079IFF, IS-2.07E-15, • RD-1170, RS-1170, TAU-0.71PS) * .MODEL TD4 D(IS-.312E-12, RS-1745, N-1.1, TT-.59PS, CJO-8.02E-15, • VJ-0.72, EG-1.42, BV-8, IBV-1E-3) • •Independent Sources VDD 2 0 4.5 VSS 1 0 - 3 • •Pulse Feedthrough at Vbias * VSIN 25 0 PULSE(-2.9 -.3 5PS 5PS 5PS 25PS 200PS) VGGB 24 0 -0.3 VRFB 3 0 -0.6 .TRAN 0.25PS 50PS UIC .PRINT TRAN V<26) V(23) V{20) . END ISAB RI26R912T3 Off Isolation * •Cycle Controls and List ing Options .OPTIONS ITL4-1000 ITL5-0 LIMPTS-2000 NOPAGE NOMOD .WIDTH OUT-80 * • • •«»»*******ISAB Circuit******* • BSS 9 26 6 R12S 60 BSG2 11 24 10 R12G2 60 VI 23 6 0 V3 9 10 0 V4 11 20 0 VS 25 26 0 » XAMP1 20 21 12 AMP •ISAB Circui t Passive and Parasit ic Components CFIXED 110 39FF • • • • • • • • • • • E n d ISAB Circuit******* •Amplifier Subcircuit • .SOBCKT AMP 3 5 1 2 BIN 4 3 0 RSAG12 67 BFB 4 5 0 RSAG12 23 BLPU 2 4 4 RSAG12 45 BPU 2 4 6 RSAG12 90 Dl 6 7 TD4 66 D2 7 8 TD4 66 D3 8 5 TD4 66 BPD 5 1 1 RSAG12 90 .ENDS AMP • •Active Element Models .MODEL R12S GASFET<VTO«-2, VBI-1.23, RG-0.83, ALPHA-2.3, BETA-3.1E-5 + LAMBDA-0.055, CGSO-0.595FF, CGD-0.595FF, CDS-0.0791FF, IS-2.07E-15, + RD-705, RS-1170, TAU-0.71PS) .MODEL R12G2 GASFET(VTO--2, VBI-1.23, RG-0.83, ALPHA-2.3, BETA-3.1E-5 + LAMBDA-0.055. CGSO-0.595FF. CGD-0.595FF. CDS-0.0791FF. IS-2.07E-15. + RD-1170, RS-705, TAU-0.71PS) .MODEL RSAG12 GASFET(VTO--2, VBI-1.23, RG-0.83, ALPHA-2.3, BETA-3.1E-S • LAMBDA-0.055, CGSO-0.595Fr, CGD-0.595FF, CDS-0.0791FF, IS-2.07E-15, + RD-1170, RS-1170, TAU-0.71PS) • .MODEL TD4 D<IS-.312E-12. RS-1745, N-1.1, TT-.59PS, CJO-8.02E-15, + VJ-0.72, EG-1.42, BV-8, IBV=1E-3> * •Independent Sources VDD 2 0 4.5 VSS 1 0 - 3 * •Off Isolation with 10 GHz Sine RF Input • RSHUNT 23 20 0.4E8 VRFIN 23 0 SlN<-0.6 0.2 10GHZ) VSGB 25 0 -2.9 VGGB 24 0 -0.3 .TRAN 2PS 100PS .PRINT TRAN V(23> V{20) V(21) . END ISAB RI26R912T3 Tracking with 100PS Aperture • •Cycle Controls and List ing Options .OPTIONS ITL4-1000 ITL5-0 LIMPTS-2000 NOPAGE NOMOD .WIDTH OUT-80 • • • • • • • • • • • • • • I S A B Circuit******* * BSS 9 26 6 R12S 60 BSG2 11 24 10 R12G2 60 VI 23 6 0 V3 9 10 0 V4 11 20 0 V5 25 26 0 • XAMP 1 20 21 1 2 AMP •ISAB Circui t Passive and Parasit ic Components CFIXED 11 0 39FF IC--0.6 • • • • • • • • • • • E n d ISAB Circuit******* •Amplifier Subcircuit 159 .SUBCKT AMP 3 5 12 BIN 4 3 0 RSAG12 67 BFB 4 5 0 RSAG12 23 BLPU 2 4 4 RSAG12 45 BPU 2 4 6 RSAG12 90 01 6 7 TD4 66 02 7 8 TD4 66 03 8 5 T04 66 BPD 5 1 1 RSAG12 90 •ENDS AMP • •Active Element Models •MODEL R12S GASFET<VTO--2, VBI-1.23, RG-0.83, ALPHA-2.3. BETA-3.1E-5 • LAMBDA-0.055, CGSO-0.595FF, CGD-0.595FF, CDS-0.0791FF, IS-2.07E-15, + RD-705, RS-1170, TAU=0.71PS) .MODEL R12G2 GASFET(VTO--2, VBI-1.23, RG-0.83, ALPHA-2.3, BETA-3.1E-5 + LAMBDA-0.055, CGS0-0.595FF, CGD-0.595FF, CDS-0.0791FF, IS-2.07E-15, + RD-1170, RS-705, TAU-0.71PS) .MODEL RSAG12 GASFET(VTO--2, VBI-1.23, RG-0.83, ALPHA-2.3, BETA-3.1E-5 + LAMBDA-0.055, CGSO-0.595FF, CGD-0.595FF, CDS-0.079IFF, IS-2.07E-15. + RD-1170, RS-1170, TAU-0.71PS) * •MODEL TD4 D(IS-.312E-12, RS-1745, N-1.1, TT-.59PS. CJO-8.02E-15, + VJ-0.72, EG-1.42, BV-8. IBV-1E-3) • •Independent Sources VDD 2 0 4.5 VSS 1 0 -3 • •Sine wave Tracking at Sampling Aperture 2.3Tau • VRFIN 23 0 SIN(-0.6 0.2 250MEG) VSIN 25 0 PULSE<-2.9 -.3 5PS 5PS 5PS 100PS 410PS) VGGB 24 0 -0 .3 .THAN 10PS 4NS UIC .PRINT TRAN V(26> V<23) V(20) V(21) • .END ISAB RI26R912T3 Tracking with 25PS Aperture • •Cycle Controls and List ing Options .OPTIONS ITL4-1000 ITL5-0 LIMPTS-2000 NOPAGE NOMOD .WIDTH OUT-80 • » • • • * • • * » • • » • I S A B Circuit******* * BSS 9 26 6 R12S 60 BSG2 11 24 10 R12G2 60 V1 23 6 0 V3 9 10 0 V4 11 20 0 V5 25 26 0 * XAMP1 20 21 1 2 AMP •ISAB Circui t Passive and Parasit ic Components CFIXED 11 0 39FF IC--0.6 • ( . • • • • • • • • •End ISAB Circuit******* •Amplifier Subcircuit • .SUBCKT AMP 3 5 12 BIN 4 3 0 RSAG12 67 BFB 4 5 0 RSAG12 23 BLPU 2 4 4 RSAG12 45 BPU 2 4 6 RSAG12 90 Dl 6 7 TD4 66 D2 7 8 TD4 66 D3 8 5 TD4 66 BPD 5 1 1 RSAG12 90 .ENDS AMP • •Active Element Models .MODEL R12S GASFET(VTO--2. VBI-1.23, RG-0.83, ALPHA-2.3, BETA-3.1E-5 • LAMBDA-0.055, CGSO-0.595FF, CGD-0.595FF, CDS-0.0791FF. IS-2.07E-15, + RD-705, RS-1170, TAO-0.71PS) .MODEL R12G2 GASFET<VTO--2, VBI-1.23, RG-0.83, ALPHA-2.3, BETA-3.1E-5 + LAMBDA-0.055, CGSO-0.595FF, CGD-0.595FF, CDS-0.0791FF, IS-2.07E-15, + RD-1170, RS-705, TAU-0.71PS) .MODEL RSAG12 GASFET(VTO—2, VBI-1.23, RG-0.83, ALPHA-2.3, BETA-3.1E-5 • LAMBDA-0.055, CGSO-0.595FF, CGD-0.595FF, CDS-0.0791FF, IS-2.07E-15, • RD-1170, RS-1170. TAO-0.71PS) • .MODEL TD4 D(IS-.312E-12, RS-1745, N-1.1, TT-.59PS. CJO-8.02E-15, • VJ-0.72, EG-1.42, BV-8, IBV-1E-3) * •Independent Sources VDD 2 0 4.5 VSS 1 0 -3 • •Sine wave Tracking at Sampling Aperture • VRFIN 23 0 SIN(-0.6 0.2 1GHZ) VSIN 25 0 PULSE<-2.9 -.3 5PS SPS SPS 25PS 11 OPS) VGGB 24 0 -0.3 .TRAN 2.5PS INS .PRINT TRAN V(25) V(23) V(20) V<21) . END ISAB RI16R912T3 Pulse Feedthrough • •Cycle Controls and Lis t ing Options .OPTIONS ITL4-1000 ITL5-0 LIMPTS-2000 NOPAGE NOMOD .WIDTH OUT-80 • • • • • • • • • • • • • • I S A B Circuit******* • BSS 11 26 6 RSAG12 60 VI 23 6 0 V4 1 1 20 0 V5 25 26 0 * XAMP1 20 21 1 2 AMP •ISAB Circuit Passive and Parasit ic Components CFIXED 11 0 152FF IC--0.6 CRFPAD 23 0 20FF LRFIN 13 23 0.16NH RRFIN 3 13 50 • • • • • • • • • • • E n d ISAB Circuit******* •Amplifier Subcircuit • .SUBCKT AMP 3 5 1 2 BIN 4 3 0 RSAG12 67 BFB 4 5 0 RSAG12 23 BLPU 2 4 4 RSAG12 45 BPU 2 4 6 RSAG12 90 Dl 6 7 TD4 66 D2 7 8 TD4 66 D3 8 5 TD4 66 BPD 5 1 1 RSAG12 90 .ENDS AMP • •Active Element Models • MODEL RSAG12 GASFET(VT0--2, VBI-1.23, RG-0.83, ALPHA-2.3, BETA-3.1E-5 • LAMBDA-0.055, CGSO-0.595FF. CGD-0.595FF, CDS-0.0?91FF. IS-2.07E-15. + RD-1170, RS-1170, TAU-0.71PS) • .MODEL TD4 D<IS-.312E-12, RS-1745, N-1.1, TT-.59PS, CJO-8.02E-15, + VJ-0.72, EG-1.42, BV-8, IBV-1E-3) • •Independent Sources VDD 2 0 4.5 VSS 1 0 -3 • •Pulse Feedthrough at vbias • VSIN 25 0 PULSE(-2.9 -.3 5PS 5PS 5PS 25PS 200PS> VRFB 3 0 -0.6 .TRAN 0.25PS 50PS UIC .PRINT TRAN V(26) V{23) V(20) . END ISAB RH6R912T3 Off Isolation • •Cycle Controls and Lis t ing Options .OPTIONS ITL4-1000 ITL5-0 LIMPTS-2000 NOPAGE NOMOD • WIDTH OUT-80 * • • • • • • • • • • • • • I S A B Circuit******* • BSS 11 26 6 RSAG12 60 VI 23 6 0 Vt 11 20 0 V5 25 26 0 • XAMP1 20 21 1 2 AMP •ISAB Circu i t Passive and Parasit ic Components CFIXED 11 0 152FF • • • • • • • • • • • E n d ISAB Circuit******* •Amplifier Subcircuit * .SUBCKT AMP 3 5 12 BIN 4 3 0 RSAG12 67 BFB 4 5 0 RSAG12 23 BLPU 2 4 4 RSAG12 45 BPU 2 4 6 RSAG12 90 D1 6 7 TD4 66 D2 7 8 TD4 66 D3 8 5 TD4 66 BPD 5 1 1 RSAG12 90 .ENDS AMP • •Active Element Models .MODEL RSAG12 GASFET(VTO--2, VBI-1.23, RG-0.83, ALPHA-2.3, BETA-3.1E-5 + LAMBDA-0.055, CGSO-0.595FF, CGD-0.595FF, CDS-0.0791FF, IS-2.07E-15, + RD-1170, RS-1170, TAU-0.71PS) • .MODEL TD4 D(IS-.312E-12, RS-1745, N-1.1, TT-.59PS, CJO-8.02E-15, • VJ-0.72, EG-1.42, BV-8, IBV-1E-3) • •Independent Sources VDD 2 0 4.5 VSS 1 0 - 3 * •Off Isolation with 10 GHz Sine RF Input ) 162 RSHUNT 23 20 .25E8 VRFIN 23 0 SIN(-0.6 0.2 10GHZ) VSGB 25 0 -2.9 .TRAN 2PS 100PS .PRINT TRAN V<23) V<20) V(21) • END ISAB RI16R912T3 Tracking with 100PS Aperture * •Cycle Controls and Lis t ing Options •OPTIONS ITL4-1000 ITL5-0 LIMPTS-2000 NOPAGE NOMOD •WIDTH OUT-80 • •*«***«****«*ISAB Circuit******* * BSS 11 26 6 RSAG12 60 VI 23 6 0 V4 11 20 0 V5 25 26 0 • ZAMP1 20 21 1 2 AMP •ISAB Circuit Passive and Parasit ic Components CFIXED 11 0 152FF IC--0.6 • ***t*»****End ISAB Circuit******* •Amplifier Subcircuit • .SUBCKT AMP 3 5 1 2 BIN 4 3 0 RSAG12 67 BFB 4 5 0 RSAG12 23 BLPU 2 4 4 RSAG12 45 BPU 2 4 6 RSAG12 90 DI 6 7 TD4 66 D2 7 8 TD4 66 D3 8 5 TD4 66 BPD 5 1 1 RSAG12 90 . ENDS AMP • •Active Element Models .MODEL RSAG12 GASFET(VTO--2, VBI-1.23, RG-0.83, ALPHA-2.3. BETA-3.1E-5 + LAMBDA-0.055, CGSO-0.595FF. CGD-0.595FF, CDS-0.0791FF, IS-2.07E-15, + RD-1170, RS-1170, TAU-0.71PS) * .MODEL TD4 D(IS-.312E-12, RS-1745, N-1.1, TT-.59PS, CJO-8.02E-15. + VJ-0.72, EG-1.42, BV-8. IBV-1E-3) » •Independent Sources VDD 2 0 4.5 VSS 1 0 -3 * •Sine wave Tracking at Sampling Aperture * VRFIN 23 0 SIN(-0.6 0.2 250MEG) VSIN 25 0 PULSE(-2.9 -.3 5PS 5PS 5PS 100PS 410PS) .TRAN 2.5PS 1NS UIC .PRINT TRAN V(26> V(23) V(20) V(21> .END ISAB RI16R912T3 Tracking with 25PS Aperture « •Cycle Controls and List ing Options .OPTIONS ITL4-1000 ITL5-0 LIMPTS-2000 NOPAGE NOMOD .WIDTH OUT-80 • • • • • • • • • • • • • • I S A B Circuit******* BSS 11 26 6 RSAG12 60 VI 23 6 0 V4 11 20 0 V5 25 26 0 • XAMP1 20 21 1 2 AMP •ISAB Circu i t Passive and Parasit ic Components CFIXED 11 0 152FF IC--0.6 • • • • • • • • • • • E n d ISAB C i r c u i t » » « » « » » •Amplifier Subcircuit * • SUBCKT AMP 3 5 12 BIN 4 3 0 RSAG12 67 BFB 4 5 0 RSAG12 23 BLPU 2 4 4 RSAG12 45 BPU 2 4 6 RSAG12 90 Dl 6 7 TD4 66 D2 7 8 TD4 66 D3 8 5 TD4 66 BPD 5 1 1 RSAG12 90 .ENDS AMP * •Active Element Models .MODEL RSAG12 GASFET(VTO--2, VBI-1.23, RG-0.83, ALPHA-2.3, BETA-3.1B-5 • LAMBDA-0.055, CGS0-0.595FF, CGD-0.595FF, CDS-0.0791FF, IS-2.07E-15, • RD-1170, RS-1170, TAU-0.71PS) * .MODEL TD4 D<IS-.312E-12, RS-1745, N-1.1, TT-.59PS, CJO-8.02E-15, + VJ-0.72, EG-1.42, BV-8, IBV-1E-3) * •Independent Sources VDD 2 0 4.5 VSS 1 0 -3 • •Sine wave Tracking at Sampling Aperture • VRFIN 23 0 SIN(-0.6 0.2 1GHZ) VSIN 25 0 PULSE(-2.9 -.3 5PS SPS 5PS 25PS 110PS) .TRAN 2.5PS 1NS UIC .PRINT TRAN V(26) V(23> V<20) V(21> .END ISAB RI16R922T3 Pulse Feedthrough • •Cycle Controls and Lis t ing Options .OPTIONS ITL4-1000 ITL5-0 LIMPTS-2000 NOPAGE NOMOD .WIDTH OUT-80 • •* • • •** • • • • •* ISAB Circuit******* • BSS 1 1 2 6 6 RSAG22 60 V1 23 6 0 V4 11 20 0 V5 25 26 0 • XAMP1 20 21 1 2 AMP •ISAB Circu i t Passive and Parasit ic Components CFIXED 11 0 74FF IC--0.65 CRFPAD 23 0 20FF LRFIN 13 23 0.16NH RRFIN 3 13 50 • • • • • • • • • • • E n d ISAB Circuit******* •Amplifier Subcircuit •SUBCKT AMP 3 5 12 BIN 4 3 0 RSAG22 67 BFB 4 5 0 RSAG22 23 BLPU 2 4 4 RSAG22 45 BPU 2 4 6 RSAG22 90 Dl 6 7 TD4 40 D2 7 8 TD4 40 D3 8 5 TD4 40 BPD 5 1 1 RSAG22 90 .ENDS AMP • •Active Element Models • MODEL RSAG22 GASFET<VTO--2, VBI-1.23. RG-0.5. ALPHA-2.3, BETA-2.61E- + LAMBDA-0.055, CGS0-1.19FF, CGD-I.19FF. CDS-0.096FF, IS-4.13E-15. + RD-1555, RS-1555, TAU-2.86PS) • • MODEL TD4 D(IS-. 312E-12, RS-1745, N-1.1, TT-.59PS, CJO-8.02E-15, + VJ-0.72, EG-1.42, BV-8, IBV-1E-3) • •Independent Sources VDD 2 0 4.5 VSS 1 0 -3 • •Pulse Feedthrough at Vbias • VSIN 25 0 PULSE<-2.95 -.35 5PS 5PS 5PS 25PS 200PS) VRFB 3 0 -0.65 .TRAN 0.25PS 50PS UIC .PRINT TRAN V<26) V(23) V(20) .END ISAB RI16R922T3 Off Isolation • •Cycle Controls and Lis t ing Options •OPTIONS ITL4-1000 ITL5-0 LIMPTS-2000 NOPAGE NOMOD •WIDTH OUT-80 • • • • • • • • • • • • • • I S A B Circuit******* • BSS 11 26 6 RSAG22 60 VI 23 6 0 V4 11 20 0 V5 25 26 0 * ZAMP1 20 21 1 2 AMP •ISAB Circui t Passive and Parasit ic Components CFIXED 11 0 74FF • • • • • • • • • • • E n d ISAB Circuit******* •Amplifier Subcircuit * •SUBCKT AMP 3 5 12 BIN 4 3 0 RSAG22 67 BFB 4 5 0 RSAG22 23 BLPU 2 4 4 RSAG22 45 BPU 2 4 6 RSAG22 90 Dl 6 7 TD4 40 D2 7 8 TD4 40 D3 8 5 TD4 40 BPD 5 1 1 RSAG22 90 •ENDS AMP * •Active Element Models •MODEL RSAG22 GASFET(VTO--2, VBI-1.23, RG-0.5, ALPHA-2.3, BETA-2.61E- + LAMBDA-0.055, CGS0-1.19FF, CGD-1.19FF, CDS-0.096FF, IS-4.13E-15, + RD-1555, RS-1555, TAU-2.86PS) 1 6 5 •MODEL TD4 D<IS-•312E-12, RS-1745, N-1.1, TT-.59PS, CJO-8.02E-15, • VJ-0.72, EG-1.42, BV-B, IBV-1E-3) » •Independent Sources VDD 2 0 4.5 VSS 1 0 - 3 • •Off Isolation with 10 GHz Sine RF Input • RSHUNT 23 20 0.5E8 VRFIN 23 0 SIN(-0.65 0.2 10GHZ) VSGB 25 0 -2.95 .TRAN 2PS 100PS .PRINT TRAN V(23) V<20) V(21> . END ISAB RH6R922T3 Tracking with 100PS Aperture * •Cycle Controls and List ing Options .OPTIONS ITL4-1000 ITL5«0 LIMPTS-2000 NOPAGE NOMOD .WIDTH OUT-80 • ****»***»***»ISAB Circuit******* • BSS 11 26 6 RSAG22 60 V I 2 3 6 0 V4 11 20 0 V5 25 26 0 • ZAMP1 20 21 1 2 AMP •ISAB Circu i t Passive and Parasit ic Components CFIZED 11 0 74FF IC--0.65 • •«********End ISAB Circuit******* •Amplifier Subcircuit • .SUBCKT AMP 3 5 12 BIN 4 3 0 RSAG22 67 BFB 4 5 0 RSAG22 23 BLPU 2 4 4 RSAG22 45 BPU 2 4 6 RSAG22 90 D1 6 7 TD4 40 D2 7 8 TD4 40 D3 8 5 TD4 40 BPD 5 1 1 RSAG22 90 .ENDS AMP • •Active Element Models .MODEL RSAG22 GASFET(VTO--2, VBI-1.23, RG-0.83, ALPHA-2.3, BETA-3.1E-5 + LAMBDA-0.055, CGSO-0.595FF, CGD-0.595FF, CDS-0.0791FF, IS-2.07E-15, + RD-1170, RS-1170, TAU-0.71PS) • .MODEL TD4 D<IS-.312E-12, RS-1745, N-1.1, TT-.59PS, CJO-8.02E-15, • VJ-0.72, EG-1.42, BV-8, IBV-1E-3) * •Independent Sources VDD 2 0 4.5 VSS 1 0 -3 • •Sine wave Tracking at Sampling Aperture 2.3Tau * VRFIN 23 0 SIN(-0.65 0.2 250MEG) VSIN 25 0 PULSE(-2.95 -.35 5PS 5PS 5PS 100PS 410PS) .TRAN 10PS 4NS UIC .PRINT TRAN V(25) V(23) V<20) V(21) .END ISAB RI16R922T3 Tracking with 25PS Aperture • •Cycle Controls and List ing Options .OPTIONS ITL4-1000 ITL5-0 LIMPTS-2000 NOPAGE NOMOD .WIDTH ODT=80 • • • • • • • • • • • • • • I S A B Circuit******* • BSS 11 26 6 RSAG22 60 VI 23 6 0 V4 11 20 0 VS 25 26 0 • XAMP1 20 21 1 2 AMP •ISAB Circui t Passive and Parasit ic Components CFIXED 11 0 74FF IC--0.65 • • • • • • • • • • • E n d ISAB Circuit******* •Amplifier Subcircuit • _ .SUBCKT AMP 3 5 12 BIN 4 3 0 RSAG22 67 BFB 4 5 0 RSAG22 23 BLPU 2 4 4 RSAG22 45 BPU 2 4 6 RSAG22 90 DI 6 7 TD4 40 D2 7 8 TD4 40 D3 8 5 TD4 40 BPD 5 1 1 RSAG22 90 .ENDS AMP • •Active Element Models .MODEL RSAG22 GASFET<VTO-- 2, VBI-1.23, RG-0.25, ALPHA-2.3. BETA-2.61E-5 • LAMBDA-0.055, CGS0-1.19FF. CGD-1.19FF, CDS-0.096FF. IS-4.13E-15, + RD-1555, RS-1555, TAU-2.86PS) * .MODEL TD4 D<IS-.312E-12, RS-1745, N-1.1, TT-.59PS, CJO-8.02E-1S, + VJ-0.72, EG-1.42, BV-8, IBV-1E-3) • •Independent Sources VDD 2 0 4.5 VSS 1 0 -3 • •Sine wave Tracking at Sampling Aperture Tau * VRFIN 23 0 SIN(-0.65 0.2 1GH2) VSIN 25 0 PULSE(-2.95 -.35 5PS 5PS 5PS 25PS HOPS) .TRAN 2.5PS 1NS UIC .PRINT TRAN V(26) V(23) V(20) V<21) .END

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