Effects of Incident Angle on Single-Event Leakage Current Degradation in Heavy-Ion Irradiated 1800- and 4500-V SiC Power MOSFETs

Experimental heavy-ion responses of two variants of silicon carbide (SiC) power metaloxidesemiconductor field-effect transistors (MOSFETs) are evaluated. The devices have similar epitaxial thickness but different dopings. The higher doping in the epitaxial region results in lower breakdown voltage and typically leads to a lower threshold drain voltage at which single-event leakage current (SELC) occurs. Furthermore, the heavy-ion-induced SELC degradation in the drain and gate currents of the SiC MOSFETs exhibits a strong dependence on the heavy-ion’s angle of incidence. The devices’ behavior significantly alters when irradiated with heavy-ions at different incident angles under the same fixed bias and total fluence, as also confirmed by 3-D technology computer aided design (TCAD) simulations.