High dose gamma-ray irradiation of SiC Schottky rectifiers

Abstract

SiC Schouky rectifiers were irradiated with Co-60 γ-rays at doses up to approximately 600 Mrad. The reverse breakdown voltage (VB) was reduced from 550 to 330 V for all these doses. The forward current-voltage characteristics were significantly degraded by the irradiation, even at the lowest doses (300 Mrad). The forward current after irradiation was reduced by more than three orders of magnitude at 1.5 V bias and the Ni Schottky metal showed major changes in morphology whose extent correlated with the γ-dose. The SiC appears to be stable to very high doses and the observed changes in device performance are due to metal contact failures. The power figure-of-merit VB2/Ron, where Ron is the on-state resistance, degraded from 4560 kW cm-2 in the unirradiated rectifiers to 11 kW cm-2 after a dose of 600 Mrad. © 2003 The Electrochemical Society. All rights reserved.