Failure Mechanism of Double-Trench (DT) 4H-SiC Power MOSFET under UIS Measurement

In this paper, failure mechanism of DT 4H-SiC power MOSFET under unclamped inductive switch (UIS) test is evaluated by combination experiment and theoretical research. The results show that unlike planar MOSFET, the gate oxide at corner trench destroyed UIS test, therefore, device failed. And then, measurement leakage resistance between source (<i>R</i><sub>gs</sub>) failed indicate increases sharply <i>R</i><sub>gs</sub> only 25 Ω, however, threshold voltage unchanged. analysis inner electrical field avalanche state using TCAD software shows maximum exists junction temperature does not exceed melt point metal. These are consistent with experimental .