In this study, the short-circuit failure mechanisms of 1.2 kV double trench SiC MOSFETs were investigated by experiment and three-dimensional numerical TCAD simulation. Damage at the gate interlayer dielectric was confirmed as the cause of failure in the case of 400 V drain-source bias short-circuit transient. The three-dimensional TCAD simulation results showed that the high level of mechanical stress could cause the structural damage observed in the interlayer dielectric. Stress component analysis showed that tensile stress and shear stress were the principal stresses that caused the damage. The typical thermal runaway failure caused by activation of bipolar characteristics at extremely high temperature was confirmed, by experiment and simulation, in the case of the 800 V drain-source bias short-circuit transient. The three-dimensional simulation results indicated that activation of the bipolar junction transistor initially occurred near the gate cross-corner, and then spread throughout the entire cell.

在这项研究中，通过实验和三维数值TCAD仿真研究了1.2 kV双沟槽SiC MOSFET的短路故障机理。在400 V漏极-源极偏置短路瞬变的情况下，确认了栅极层间电介质的损坏是故障的原因。三维TCAD仿真结果表明，高水平的机械应力可能会导致在层间电介质中观察到的结构破坏。应力分量分析表明，拉应力和剪应力是造成损伤的主要应力。通过实验和仿真，在800 V漏-源偏置短路瞬变的情况下，已确认了在极高温度下激活双极性特性导致的典型热失控故障。