Experimental and theoretical analyses of gate oxide and junction reliability for 4H-SiC MOSFET under short-circuit operation

In this study, the experimental evaluation and numerical analysis of the short-circuit capability of the 1200 V SiC MOSFET with a thin gate oxide layer were carried out. Two different failures, including the gate oxide breakdown and thermal runaway of the device caused by the high gate electric field and elevated lattice temperature, were initially investigated and their critical temperature points for two failure modes were accurately extrapolated by solving the thermal diffusion equation; the obtained results are in good agreement with simulation results. It was confirmed that short-circuit robustness depends not only on thermal properties of the material but also on dimensional parameters of the device and that the heat is the dominant factor that causes device failure during short-circuit transient.