The effects of high-dose gamma irradiation on high-voltage 4H-SiC Schottky diodes and the SiC-SiO/sub 2/ interface

The effects of radiation on high-voltage 4H-SiC Schottky diodes for use in extreme environment power supplies are investigated for the first time. Diodes were fabricated with a wide range of barrier heights (1.06-1.60 eV) and were evaluated after being exposed to a /sup 60/Co gamma radiation source. DC current-voltage characteristics were measured after several radiation doses, with no observable degradation in the diode forward or reverse characteristics up to a total dose of 4 Mrad(Si). Measured breakdown voltages of post-irradiated diodes increase approximately 200 V compared to the virgin devices and are attributed to increased negative interface charge, as determined by MOS capacitor measurements and correlated with numerical breakdown simulations.