Investigations of Residual Damage in SiC Trench MOSFETs after Single and Multiple Short-Circuit Stress

This study investigated the residual damage to 1.2 kV SiC trench MOSFETs after being subjected to single or multiple short-circuit stress tests. The SiC trench MOSFETs showed higher gate leakage current ($I_{\mathrm{G}}$) than $S$ iC planar MOSFETs with short-circuit transient. However, the SiC planar MOSFETs showed a large positive shift of the $I_{\mathrm{D}}-V_{\text{GS}}$ curve after single short-circuit stress tests despite lower $I_{\mathrm{G}}$, while the $S$ iC trench MOSFETs with higher $I_{\mathrm{G}}$ did not show such degradation. This could be caused by electrons trapped in the higher density oxide traps in the SiC planar MOSFETs during the single short-circuit stress tests regardless of the size of $I_{\mathrm{G}}$. It was also found that multiple short-circuit stress tests to the $S$ iC trench MOSFETs did not affect $I_{\mathrm{D}}-V_{\text{GS}}$ stability. These results indicate that SiC trench MOSFETs have superior stability against short-circuit stress compared to SiC planar MOSFETs.