Saturation behavior of silicon Auston switches

The laser-energized photoconductive switch (Auston switch) has been described previously with various applications. We report new measurements investigating the physical behavior of several types of silicon Auston switches, establishing basic quantum efficiency, charge-voltage behavior, and voltage-time response. Previously predicted nonlinear effects are observed, resulting in departures from ideal performance for most designs. However, operation in the saturated mode and a transmission line environment allows several designs to produce a step waveform that gives previously unattainable combinations of amplitude and rise time. In particular, the goal of a low aberration, 150-V, 35-ps step has been achieved, and process parameters affecting this performance are described.