Investigation of Potential Impact of Nitridation Process on Single Event Gate Rupture Tolerance in SiC MOS Capacitors

Abstract

Single Event Gate Rupture (SEGR) is one of the catastrophic failures caused by heavy ions in power MOS devices. In this study, n-type SiC MOS capacitors representing the gate structure generally used in SiC power MOSFETs were used to conduct heavy ion irradiation tests to clarify the SEGR mechanism. The Linear Energy Transfer (LET) dependence of the critical electric field (Ecr) for these capacitors was evaluated with two different oxidation processes in accumulation to confirm whether the oxidation process affects SEGR tolerance. We found that the Ecr value and slopes of the LET dependence for SEGR between DRY samples and DRY + POA samples were approximately consistent. We also simulated SEGR and studied its mechanism. The simulation results suggested that SEGR for SiC MOS capacitors is caused by carriers in electron-hole pairs generated by a heavy ion instead of gate electric field fluctuation.