An Improved 4H-SiC Trench MOS Barrier Schottky Diode With Lower On-Resistance

An improved 4H-SiC trench MOS barrier Schottky (TMBS) structure that can significantly reduce the specific on-resistance (R-on,R-sp) is proposed in this paper. Compared with the conventional TMBS structure, an N-type region is added around the P+ shielding region and along the trench sidewall in the proposed structure, and the doping concentration is higher than that of the drift region. The JFET resistance, and spread resistance can both be reduced significantly during the forward bias to produce a much lower R-on,R-sp, which have been verified through the numeric simulations and modeling analysis. The critical parameters (N-type region width and its doping concentration) of the proposed structure are mainly optimized by the ATLAS simulation tool. As a result, the breakdown voltage and leakage current of the improved structure remain basically unchanged compared with the conventional TMBS. However, the R-on,R-sp and FoM (BV2/R-on,R-sp) can be effectively improved by 41.9% and 70.9%, respectively.