Impact of Gamma Ray Irradiation on the Blocking Characteristics of Edge Termination on 4H-SiC and a Novel Anti-Ionizing Radiation Technology

The impact of gamma ray irradiation on the blocking characteristics of edge termination on 4H-SiC has been investigated. The dominant mechanism for the degradation of breakdown voltage (VBD) is the trapping of net positive charges in the field oxide (FOX), while the increase in interface state density can be ignored. Through measurements of FOX MOSFETs and edge termination test structures, we found that edge termination with LOCal Oxidation of SiC (LOCOSiC) FOX exhibits lower variation in $\mathrm {V_{BD}}$ compared to conventional CVD FOX. Furthermore, it shows almost no susceptibility to gamma-ray irradiation up to 250 kGy. Therefore, it is recommended to utilize LOCOSiC FOX to mitigate the impact of irradiation on the blocking characteristics of SiC power devices’ edge termination.