Evaluation of atmospheric-neutron-induced failure rates in sic power diodes via spallation neutron irradiation

The single-event burnout (SEB) phenomenon induced by terrestrial neutron in SiC power diodes is examined through spallation neutron irradiation experiments. The findings indicate that reverse bias voltage serves as the primary factor affecting atmospheric neutron-induced failure rates. Specifically, the SEB failure rate of SiC diodes exhibits an exponential increase with rising bias voltage. For devices with varying rated voltages, the atmospheric neutron failure rate demonstrates a consistent trend when plotted against the ratio of bias voltage to rated voltage. Under room temperature conditions at sea level, the failure rate for SiC diodes operating at their rated voltage is approximately 18.7 FIT. When the operating voltage is decreased to 50% of the rated value, the atmospheric neutron failure rate significantly drops to 0.33 FIT. Additionally, higher altitudes, which are associated with increased atmospheric neutron flux, lead to proportionally elevated SEB failure rates. For instance, the SEB failure rate of the same SiC devices deployed in a high-altitude region at 4000 meters in Tibet is nearly 18 times greater than that observed at sea level in Guangzhou.