Effects of Heating on Photoconductive Semiconductor Switches: Simulation and Analysis

A non-linear vertical GaAs photoconductive switch with device dimensions of 27004times630times1 microns and diagonally opposed palladium contacts was used. The primary material used in the photo-switches is Liquid encapsulated Czochralski (LEC) grown GaAs, in which deep donors are compensated by shallow acceptors. The anode was heated to a temperature of 330 K. The devices were analyzed in terms of carrier conduction process during the charging state. It was found that the device showed current controlled negative resistivity behavior at elevated temperature, which would enhance the filamentary conduction process of the device and lead to thermal runaway. As a result, the switch performance will be severely affected leading to the damage of the electronic system.