Total-Ionizing-Dose and Displacement Damage Effects in Trench SiC Power MOSFETs

This study explores the total ionizing dose (TID) and displacement damage (DD) effects in trench silicon carbide (SiC) power MOSFETs. The effects of X-ray irradiation reveal significant negative shifts in the threshold voltage, particularly evident in devices biased with positive gate bias. The TID effects in those devices are visible at doses as low as 10 krad(SiO2), indicating the higher TID sensitivity of trench devices compared to some planar counterparts. Exposure to 3-MeV protons leads to substantial reductions in drain current induced by a fall in the transconductance, while no damage to the gate oxide is observed up to doses of 50 Mrad(SiO2). The substantial degradation of transconductance indicates DD, which become prominent at doses exceeding 10 Mrad(SiO2). Both trench and planar devices exhibit similar DD-induced effects, suggesting a common underlying mechanism linked to defects within the epitaxial SiC layer.