Design Optimization of a High Temperature 1.2 kV 4H-SiC Buried Grid JBS Rectifier

Abstract

1.2 kV SiC buried grid junction barrier Schottky (BG-JBS) diodes are demonstrated. The design considerations for high temperature applications are investigated. The design is optimized in terms of doping concentration and thickness of the epilayers, as well as grid size and spacing dimensions, in order to obtain low on-resistance and reasonable leakage current even at high temperatures. The device behavior at temperatures ranging from 25 to 225ºC is analyzed and measured on wafer level. At 100 A/cm2 a forward voltage drop of 2 V at 25ºC and 3 V at 225ºC is achieved. At reverse voltage of 1 kV, a leakage current density below 0.1 µA/cm2 and below 0.1 mA/cm2 is measured at 25 and 225ºC, respectively. This proves the effective shielding effect of the BG-JBS design and provides benefits in high voltage applications, particularly for high temperature operation.