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.