Degradation Mechanism in Aged SiC MOSFETs Under Repetitive Short-Circuit

The robustness of silicon carbide (SiC) MOSFETs against repetitive short-circuit (RSC) events is a critical reliability concern for automotive electric drivetrain converters. In this article, gate switching instability (GSI) followed by RSC test is carried out to find the new degradation phenomenon of aged devices (after GSI stress). The threshold voltage (${V}_{\text {th}}\text {)}$increases first and then decreases after a certain number of RSC cycles. Furthermore, the degradation mechanism is revealed that injected charge type is transitioned by originally injected charges. Based on the mechanism, we propose the charge injection barrier modulation (CIBM) effect, which provides universal application to explain nonmonotonic gate-related parameters change under varied stress conditions. To sum up, this study gains key theoretical insights for developing accurate lifetime models and comprehensive health monitoring strategies for aged SiC MOSFETs.