Simulation of switching processes in turn-off thyristors

Fundamental equations describing carrier transport, current continuity, and potential distribution are used in a finite-difference scheme to model switching phenomena in semiconductor power devices. An irregular and variable mesh approach is introduced that can reduce computation time by 40%. If the device structure satisfies certain conditions, the method works even more effectively. The program is used to analyze gate-turn-off (GTO) thyristor and static-induction thyristor (SIT) switching. Carrier concentration, potential, and current distribution transients during switching of the devices are shown. The current squeeze and concentration during turn-off in the GTO are related to the gate structure. The effective channel width of the SIT is also determined through numerical analysis.<
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