Control of lifetime in silicon power devices using electron or gamma irradiation

Irradiation of silicon power devices is discussed for electrons of 0.8 to 12 MeV energy and gamma rays from Co-60 in terms of their effectiveness in altering device switching properties. Comparison is made with gold or platinum diffused devices. Gold diffusion provides the best tradeoff of forward voltage drop and reverse recovery time in diodes or turnoff time in thyristors. This advantage is somewhat offset by the high leakage in gold diffused devices which limits their maximum operating temperature; also irradiation provides the more precise, uniform, reproducible method of lifetime control.