Silicon and gallium arsenide vacuum surface flashover

Abstract

Photoconductive semiconductor switches (PCSS) presently have the greatest potential for dramatic performance enhancements for high power pulsed applications. However, surface flashover severely limits the maximum stand off voltage in the open state. We report the use of a novel technique to PCSS to overcome this limitation. The technique is an extension of the graded ring bushing idea from accelerator technology, but differs by reducing the thickness of the insulator (semiconductor) down to tens of micrometers. Recent results using this technique have yielded electric field values, before flashover, in the range of 70 kY/cm to 114 kVF/cm in silicon and 70 kY/cm to 84 kV/cm in gallium arsenide.