Enhanced Conduction and Switching Performance of 1.2 kV 4H-SiC MOSFETs through High JFET Doping Concentration

This paper aims to provide a comprehensive analysis of the impact of JFET doping concentration on the static and dynamic characteristics of 1.2 kV 4H-SiC MOSFETs. Different channel and JFET designs were implemented by varying the JFET doping concentrations. The utilization of high JFET doping concentrations resulted in an 18& reduction in specific on-resistance (${\mathrm {R}}_{{\mathrm {on,sp}}}$) compared to low JFET doping concentrations. This improvement was achieved by enhancing channel mobility and reducing JFET resistance. Additionally, narrow JFET widths were achieved. However, the high channel doping concentrations led to increased leakage currents, resulting in lower breakdown voltages. Nevertheless, under negative gate voltages, the issues associated with leakage currents were effectively resolved. The high JFET doping concentration demonstrated a 14& reduction in total switching loss due to the low switching loss during the turn-on transient, although it exhibited high switching loss during the turn-off transient owing to the high ${\mathrm {C_{gd}}}$.