Design and optimization of cell and multiple-zone gradient modulation field limiting ring(MGM-FLR) termination for 1700V/10A 4H-SiC merged PiN/Schottky (MPS) Diodes

Compared with traditional Si, SiC devices have become feasible candidates for the next generation of power semiconductors due to their low on-resistance characteristics and excellent high temperature, high frequency and high voltage performance. At present, a large number of silicon carbide diodes have been used in the market, mainly including junction barrier Schottky(JBS) diodes and Merged PiN Schottky(MPS) diodes. They have achieved a good balance between forward conduction, reverse blocking performance and surge and avalanche reliability. In this paper, a 1700V blocking-voltage 4H-SiC MPS is designed and simulated, which uses multiple-zone gradient modulation field limiting ring (MGM-FLR) junction termination structure. The device structure and termination protection parameters are optimized in the paper, under the optimal parameters, Technology Computer Aided Design(TCAD) simulation results show that the designed 4H-SiC MPS cell can withstand 2170V blocking-voltage and the forward-voltage drop is 1.5V without considering the termination protection. When considering the MGM-FLR termination structure, the blocking-voltage is up to 1988V, where the efficiency of termination protection can reach to 92%.