Date of Award

12-1992

Document Type

Thesis

Degree Name

Master of Science

Department

Department of Engineering Physics

First Advisor

William F. Bailey, PhD

Abstract

For many applications such as lasers and radar drive circuits, there exists a need for solid state high voltage, high current switches. Current gaseous discharge switches fail to satisfy the ruggedness, reliability, and lifetime requirements of today's systems. A promising alternative is the Photoconductive Semiconductor Switch (PCSS). The limiting factor in the operation of these switches is the occurrence of breakdown through channels formed slightly below the surface. A theory on the formation of these channels is presented based upon band bending at the metal-semiconductor interface, a nonhomogeneous space charge due to irregular trap distributions, and thermal runaway in localized regions. Experimental results on the effect of thin oxide layers and boron doping at the metal-semiconductor junctions reveal that the junctions play a very important role in the breakdown of the samples, changing the breakdown potential by almost a factor of three. By placing a thin oxide layer at the anode face of a sample, an excellent photoconductive switch can be produced. The resistance of this switch was changed by three orders of magnitude through optical illumination.

AFIT Designator

AFIT-GEP-ENP-92D-5

DTIC Accession Number

ADA259171

Comments

The author's Vita page is omitted.

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