Formation of extended defects in heavy-ion-degraded SiC power MOSFETs

Silicon carbide (SiC) power devices offer distinct advantages over silicon-based technology and are envisioned to be of great benefit also for space applications. However, their reliability in space is reduced due to the high susceptibility to space-radiation, where single event effects (SEEs) induced by heavy ions are a particular risk. This work focuses on identifying the microscopic origin of a specific non-destructive SEE in SiC power MOSFETs known as single event leakage current (SELC), characterized by a permanent degradation of the gate and drain leakage currents and observed at a relatively low blocking voltage during heavy-ion exposure. The effect investigated is categorized as SELC II, and devices exposed to both broad-beam and microbeam of heavy-ions are studied herein. Using imaging photoluminescence spectroscopy, we observe distinct bright-spots after heavy-ion irradiation, containing spectral features that indicate the formation of stacking faults during exposure and subsequent biasing.