Design and optimization of Field Limiting Rings termination for 1200V 4H-SiC VDMOSFETs

Based on the impact ionization theory, along with a series of improved models for 4H-SiC material, the breakdown characteristics simulations of 4H-SiC MOSFETs with Field Limiting Rings (FLRs) are performed in this paper with Atlas of Silvaco TCAD. 1200V 4H-SiC MOSFETs with different spaces FLRs are presented and a maximum breakdown voltage of 1940V is achieved with an optimized 15 FLRs. The optimization method for FLRs design is also discussed.