SiC Power TrenchMOS Transistor under harsh repetitive switching conditions

We investigate the reliability of 1.2kV 4H-SiC MOSFETs under repeated unclamped inductive switching (UIS) and short-circuit I and II conditions. The stress induced degradation of device characteristics, including output and transfer characteristics and drain leakage current, was analyzed. Repeated Short Circuit stress was performed for VBUSS = 600V. Repetitive UIS test was performed for 1mH inductive load. Degradation of most of the electrical parameters was observed after relatively short stress. During stress testing, hot carriers in the channel region are injected into the gate oxide, where they are trapped in existing defects or create new ones. This is thought to be responsible for the variation in electrical parameters. Charge trapping is also indicated by a significant change in switching times. The trapping effects were analyzed using the DLTFS method.