Simulation and optimization of field limiting rings for ultrahigh voltage 4H-SiC IGBT

An ultrahigh voltage 4H-SiC IGBT with field limiting rings termination is designed and simulated using SILVACO TCAD software. Detailed simulations have been performed on field limiting rings, including spacing between rings, width of rings and so on. The simulation results show that the optimized field limiting rings could provide a blocking capability of 20kV. The breakdown voltage with different positive interface charge and negative interface charge densities in consideration have been compared and discussed. The specific key parameters of optimal structure of filed limiting rings have also been presented.