A study of carrier generation in, and interaction of, space-charge regions in germanium
department or school: Science, Faculty of
department or school: Physics and Astronomy, Department of
data provider: DSpace
degree campus: UBCV
creator: Mitchell, Ronald Reid
issued: 2012-03-01T17:20:05Z
issued: 1959
related degree: Master of Applied Science - MASc
degree grantor: University of British Columbia
description: Germanium space-charge regions have been studied under conditions of double-depletion achieved by applying a reverse bias to both junctions of a transistor structure. The generation and distribution of carriers between the two junctions are described in terms of models for the thermal generation of carrier pairs and for potential distribution in a cylindrical system. Measurements over a wide range of temperature reveal that generation of carriers occurs through the medium of one or more sets of recombination centers and not by direct transition between the valence and conduction bands even at elevated temperatures. The Shockley-Read recombination-generation theory is applied to obtain the activation energies associated with the recombination centers. The impurity density, base width and junction areas are estimated from measurements of punchthrough voltage and junction capacitance. For some specimens the capacitance measurements made with one junction floating confirm the sharp increase in capacitance at punchthrough noted by Barker. The distribution of current between the junctions when both are equally reverse biased is found to be roughly proportional to their areas. It is also shown that control of the reverse current across one junction may be achieved by variation of the reverse-bias on the other junction. The mechanism of this interaction is considered in terms of the diffusion of carriers between the two space-charge regions. The phenomen of slightly non-saturating reverse current is explained in terms of the expansion with reverse bias of the space-charge region within the base. An expression relating the base current and reverse bias in a cylindrical system shown to give good agreement with experiment for one specimen. For the units in which the increase in current with voltage is appreciable, space-charge expansion cannot account for the increase and two other mechanisms are considered: avalanche multiplication in the bulk and along the surface, and a hig…
aggregated CHO: https://circle.library.ubc.ca/rest/handle/2429/41048
note: A STUDY OF CARRIER GENERATION IN, AND INTERACTION OF, SPACE-CHARGE REGIONS IN GERMANIUM by RONALD REID MITCHELL B.A.Sc, University of B r i t i s h Columbia, 1957 A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF APPLIED SCIENCE in the Department of Physics We accept th i s thesis as conforming to the required standard THE UNIVERSITY OF BRITISH COLUMBIA September, 1959 ( i i ) ABSTRACT Germanium space-charge regions have been studied under conditions of double-depletion achieved by applying a reverse bias to both junctions of a tran s i s t o r structure. The generation and d i s t r i b u t i o n of c a r r i e r s between the two junctions are described in terms of models for the thermal generation of c a r r i e r pairs and for potential d i s t r i b u t i o n in a c y l i n d r i c a l system. Measurements over a wide range of temperature reveal that generation of c a r r i e r s occurs through the medium of one or more sets of recombination centers and not by dir e c t t r a n s i t i o n between the valence and conduction bands even at elevated temperatures. The Shockley-Read recombination-generation theory i s applied to obtain the a c t i v a t i o n energies associated with the recombination centers. The impurity density, base width and junction areas are estimated from measurements of punchthrough voltage and junction capacitance. For some specimens the capacitance measurements made with one junction f l o a t i n g confirm the sharp increase in capacitance at punchthrough noted by Barker. The d i s t r i b u t i o n of current between the junctions when both are equally reverse biased i s found to be roughly proportional to the i r areas. It i s also shown that control of the reverse current across one junction may be achieved by v a r i a t i o n of the reverse-bias on the ( i i i ) other junction. The mechanism of t h i s interaction i s considered in terms of the d i f f u s i o n of c a r r i e r s between the t…
has type: Thesis/Dissertation
is shown at: 10.14288/1.0085821
language: eng
degree discipline: Physics
provider: Vancouver : University of British Columbia Library
publisher: University of British Columbia
rights: For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.
scholar level: Graduate
type: Text
identifier URI: http://hdl.handle.net/2429/41048