Simulation Study of 3-Zone Step Doping Junction Termination Extension for 20kV 4H-SiC Thyristor

A 20 kV 4H-SiC thyristor with 3-zone step doping junction termination extension is investigated in this paper. The simulation results show that the breakdown voltage of the thyristor terminated with step doping JTE can achieve 23 kV, corresponding efficiency is about 95.64%. Gaping and overlaying in the two-nested ion implantation process of three-zone JTE will lead to the surface electric field to higher. The peak of the surface electric field in the gaping case and the overlaying case are 2.13 MV/cm and 1.73 MV/cm are higher than the 1.36 MV/cm under the ideal situation. Therefore, it is necessary to strictly control the lithography process deviation to avoid gaping and overlaying situations to prevent electric field spikes within the JTE.