UBC Theses and Dissertations
Techniques for high-speed time-resolved device characterization Shah, Saurin
The objective of this thesis is to address two open issues in time-resolved measurements of electronic devices. The first is the ability to perform measurements close to the device under test: we report a new approach to recover temporally-overlapping incident and reflected signals near a device. The technique involves electro-optic measurement at two locations. With suitable time-domain or Fourier-transform processing, the measured waveforms can be decomposed into components propagating towards and away from the device. We show experimental results for coplanar structures. In the second part, we have identified a new feature in measured signals that we can attribute to substrate waves excited photoconductively during electro-optic sampling on coplanar striplines. Measurements at several positions laterally displaced from the center of the transmission line show that this substrate signal is confined to the neighborhood of the electrodes when the substrate is thin. We also show that this feature, which can be an impediment to accurate S-parameter characterization, can be eliminated by delaying it out of the time window of interest. Finally, the Appendix lists the fabrication steps and process parameters for a lift-off process used to fabricate some of the samples used in this project.
Item Citations and Data