Study on gate oxide reliability of SiC power MOSFETs under 300 MeV proton irradiation

Abstract

Although operating at a lower drain bias voltage reduces the risk of Single-Event-Burnout (SEB), whether SiC power MOSFET can be reliably applied under low-voltage irradiation conditions remains to be investigated. This study evaluated the gate oxide reliability of SiC power MOSFETs irradiated with a 300 MeV proton beam. Different drain bias levels and total fluence values were selected in the irradiation experiment. The critical voltage for SEB occurrence in the selected device samples was obtained. For devices that did not experience SEB after irradiation, their electrical characteristics remained largely unchanged; however, significant degradation in gate oxide reliability was observed during Time-Dependent Dielectric Breakdown (TDDB) tests, suggesting potential long-term reliability concerns. Furthermore, degradation of gate oxide reliability requires the irradiation bias to exceed a certain threshold, and the degradation severity is positively correlated with irradiation fluence, demonstrating a cumulative radiation damage effect. These findings provide critical insights for ensuring the reliable application of SiC power devices in aerospace systems.