Heavy-Ion Effects in SiC Power MOSFETs With Trench-Gate Design

Silicon carbide (SiC) power MOSFETs with trench-gate structure have been irradiated with heavy-ion broad beam and microbeam. Microdose effects resulting in higher subthreshold drain leakage were observed when irradiating the devices at low drain-source voltages and reported for the first time for SiC power devices. Increasing the drain-source bias during the exposure, single-event leakage current (SELC), characterized by microbreaks in the gate oxide, was measured. The accumulation of microbreaks eventually led to a complete gate rupture. The differences with respect to the SiC planar-gate MOSFETs and the impact of these results on the testing procedures for the two technologies are discussed.