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

Abstract

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 (Q s ) 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.

Design and experiment of 4H-SiC JBS diodes achieving a near-theoretical breakdown voltage with non-uniform floating limiting rings terminal

“…But for the JTE termination technology, one critical issue is that its termination efficiency is highly depended on the dose density, even a small dose variation may have a huge influence on the breakdown characteristic. So more process is usually necessary to reduce the sensitivity of dose to the breakdown voltage, such as mesa structure and multiply implantation structure [7,8]. Therefore, FLRs termination is more attractive due to the fact that its fabrication process could be simultaneously accomplished with the implanting P+ structure in the active region, and it is also not sensitive to the dose density.…”