CHARACTERIZATION OF A SEMIINSULATING GAAS PHOTOCONDUCTIVE SEMICONDUCTOR SWITCH FOR ULTRAWIDE BAND HIGH-POWER MICROWAVE APPLICATIONS

Simulation results depicting physical conditions in a photoconductive semiconductor switch in the pulse charging state, prior to high power switching, are analyzed. Results show that surface conditions and EL2 traps in semi-insulating GaAs influence the conduction process, specif ically at high bias. Formation of trap-filled regions renders the devi ce inhomogeneous for stable conduction and premature breakdown occurs, due to a large extent on unstable current filamentation within the de vice. Unlike insulators, the breakdown of desorbed gas from the surfac e (surface flashover) does not contribute to premature breakdown. (C) 1998 American Institute of Physics. [S0003-6951(98)01340-0].