Single Event Effects of SiC Power MOSFETs: From Neutron Interaction to Destruction at the Die Level

The impact of irradiation poses a significant barrier to the deployment of commercial off-the-shelf (COTS) Silicon Carbide (SiC) devices, such SiC MOSFETs, in harsh environments, such as space, avionics, and nuclear settings. Incident particles can induce secondary ion and generate, at the SiC die level, catastrophic events, such Single Event Burnout (SEB) or Single Event Gate Rupture (SEGR). With the goal of better elucidating the distinct stages occurring during irradiation, Technology Computer-Aided Design Single Event Effect (SEE) simulations of the SiC MOSFET, using ECORCE, were performed for both a heavy ion and a secondary ion created by neutron nuclear reactions. To more comprehensively account for all mechanisms linking particle interactions to device failure, the influence of two ion impact positions, beneath the gate and beneath the source, is evaluated. The critical roles of the local electric field in the gate oxide region, along with the spatial distribution of the local electrical potential and temperature profiles, are carefully examined. In the specific case of atmospheric neutrons, a secondary ion of Al is selected and all impact positions within the SiC MOSFET structure are considered. Detailed simulations provide a comprehensive mapping of the underlying mechanisms and the device’s radiation-sensitive areas. In addition, the failure analysis of two failed COTS SiC MOSFETs, with a special backside sample preparation, after atmospheric neutron irradiation, is presented and examined. The two post-neutron-irradiation failure analysis of the SiC MOSFET reveal traces of micro-explosions and combustion at the die level, corroborating the results from ECORCE TCAD simulations.