Optimization of 1700-V 4H-SiC Semi-Superjunction Schottky Rectifiers With Implanted P-Pillars for Practical Realization

A class of vertical 1700 V 4H-silicon carbide (SiC) semi-superjunction (SJ) Schottky diodes have been simulated and optimized to ensure practical cost-effective realization. The proposed structures could be realized using an n-type drift region 9- $\mu \text{m}$ etching trenches partway through this form the required mesa regions. P-pillars are then created implantation into both trench sidewalls bottom. This semi-SJ topology overcomes problems with conventional SJs that span full (full-SJs), namely a narrow charge-balance window achieve maximum notation="LaTeX">${V}_{\text {BD}}$ , hard, snappy, switching characteristics. SiC comprises 7- SJ above 2- region. An angled sidewall ( notation="LaTeX">$\alpha $ ), 10° off vertical, introduces graded charge profile throughout n-pillar, which widens by 34%, while maintaining ~2.1 kV notation="LaTeX">${R}_{ \mathrm{\scriptscriptstyle ON},\text {SP}}$ comparable full-SJ. Further advantages semi-SJ, over full-SJ, include reduced aspect ratio two orders magnitude lower leakage current. Furthermore, in n-pillar gradually depletes region, suppressing ringing reducing peak reverse recovery current 50%.