SiC Power TrenchMOS Transistor Under Repetitive Avalanche Stress

This paper investigates the robustness and reliability issues of commercial 1.2-kV 4H-SiC MOSFETs under repetitive unclamped inductive switching (UIS). The degradation of device characteristics, including the transfer characteristics, drain leakage current <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$I_{dss}$</tex> , and output characteristics, is observed. A significant increase in leakage current was observed after relatively short avalanche stress (UIS stress), and device destruction occurred after 30 million of cycles. Besides the shift of static electrical characteristics, also a change in switching times was observed. The hot carriers injection and trapping into the gate oxide and its interfaces is believed to be responsible for the variation of electrical parameters.