Study of breakdown characteristics of 4H-SiC Schottky diode with improved 2-step mesa junction termination extension

The 4H-SiC Schottky diode with 2-step mesa junction termination extension (JTE) structure has been investigated and optimized using SILVACO device simulator. Comparisons between different JTE structures of breakdown voltage and electric field crowding for Schottky diodes have been made. Simulation results show that the Space Modulated two-zone JTE has the highest breakdown voltage which is about 97% of the ideal 1D parallel plane conditions. With the novel 2-step MESA Single Implant JTE, the breakdown voltage could achieve the same as the parallel plane breakdown votlage. The influences of the surface charge (Qs) and the oxide passivation on the breakdown characteristics of 4H-SiC Schottky diode with JTE are also investigated. A reduced sensitivity of breakdown voltage with respect to P-implant doping concentration is obtained for a novel 2-step mesa JTE with an additional P-type guard ring.