Heavy-Ion Microbeam Studies of Single-Event Leakage Current Induced by Long- and Short-Range Particles in SiC Power Devices

The sensitivity to single event effects (SEEs) of commercial SiC power MOSFETs and Junction Barrier Schottky (JBS) diodes has been assessed on a micrometer scale using a focused microbeam of i) long-range and ii) short-range particles. Degradation or single event leakage current (SELC) induced by short-range particles was reported for two different generations of SiC power MOSFETs and two generations of JBS diodes. GEANT4 and TCAD simulations have been used to interpret the range dependence of SEEs. Simulations for the SELC condition in a diode structure have shown an increase in E-Field and impact ionization due to the particle strike which could be a driving force to create permanent defects. Furthermore, no sensitivity to SELC or SEB was observed in the termination regions or along the gate metal runner of two generations of power MOSFETs. Differences were observed when irradiating the devices on and off the source pad, which were attributed to the shallow ion penetration caused by the additional polyimide layer present in the off-pad region.