Heavy-ion induced gate damage and thermal destruction in double-trench SiC MOSFETs

This article presents the experimental results of the heavy-ion-induced gate oxide damage and single-event burnout (SEB) in 1200 V SiC double-trench MOSFETs. The short-circuit between any two terminals of devices under test (DUTs) was observed during the exposure with a drain bias of only 100 V and post-irradiation measurements. In addition, the experimental results also showed that the SEB threshold of DUTs does not exceed 500 V, which was lower than 42 % of the rated breakdown voltage. TCAD simulations revealed that the electric field concentrated at the corner and sidewall of gate oxide, resulting in the latent oxide damage, which should be responsible for the leakage current degradation at low drain bias. It was also verified that the SEB failure was due to the thermal destruction caused by the high temperature near the n− drift/n+ substrate junction, which was further determined by the SEM image of the die surface. The findings in this article could provide indications for future use of such state-of-the-art SiC double-trench MOSFETs in space.