Low‐leakage 4H‐SiC junction barrier Schottky rectifier with sandwich P‐type well

Abstract

4H-SiC junction barrier Schottky (JBS) rectifier with sandwich P-type well (SPW JBS) is investigated by simulation. For this structure, the top and bottom of P+ grids are replaced by low-doped P (LDP) region based on the common JBS rectifier. The forward and reverse characteristics of SPW JBS rectifier have been compared with those of common JBS rectifier at different temperatures. The reverse current density of SPW JBS rectifier is about 2.4 × 10−5 times of common JBS rectifier at −800 V bias voltage. The upper LDP of SPW JBS is helpful to give a reduction in forward voltage drop. The spreading current and tunnelling current of SPW JBS rectifier are lower, because the depletion layer width in lower LDP is larger than that in P+ grid region at the same reverse voltage. As a result, the breakdown voltage of SPW JBS rectifier increases by 83.5% compared with that of common JBS rectifier. The on/off (1 V/ −500 V) current ratios of SPW JBS and common JBS rectifiers are 3.8 × 107 and 1.2 × 103, respectively. In addition, the figure of merit of SPW JBS rectifier is 347, which is two times larger than that of common JBS rectifier.