Engineering limits of photoconductive semiconductor switches in pulsed power applications

The potential of essentially jitter free subnanosecond rise time photoconductive semiconductor switches (PCSS) for pulsed power has been explored in several previous papers. In addition to picosecond rise time and jitter, PCSS also offers low inductance, high repetition rates (GBz), and optical control. In developing large scale PCSS for pulsed power applications, one encounters many aspects of the switch which can be selected or tailored to meet the specific requirements of each application. This paper describes PCSS in terms of the switching parameters which are being stressed to meet these requirements and discusses their theoretical limits as well as those encountered in the laboratory. Recent improvements (from 20 kV/cm to 70 kV/cm) in the surface breakdown strength of silicon wafers for high voltage PCSS are reported. Several specific examples are included to illustrate and emphasize the particular switching parameters being discussed.