A novel 4H-SiC Trench MOS Barrier Schottky rectifier fabricated by a two-mask process

摘要

A two-mask process for 4H-SiC Trench MOS Barrier Schottky (TMBS) rectifiers was studied in this paper. Systematic simulations and process developments were performed and SiC TMBS devices with breakdown voltage (BV) larger than 600V were successfully fabricated. SiC TMBS devices with a mesa width of 2μm to 4μm, a trench depth 2μm and a trench oxide layer of 0.2μm oxide thickness provide good characteristics of low reverse leakage current and low forward voltage drop. This simple two-mask process (one is for defining trench and the other is for defining top electrode) gives the SiC TMBS device the advantages of getting ride of expensive processes such as high temperature Al⁺ implantations (>450°C) and ultra-high temperature activations (>1600°C). This may enable SiC TMBS a potential lost cost solution to help further widespread the adoption of SiC Schottky rectifiers.