Normally-Off 1200V Silicon Carbide JFET Diode with Low V_F

Abstract

Novel diode structure which looks like DMOSFETs with the gate-shorted to n+ source has been developed for the first time. The lateral JFET channel as a built-in channel instead of gate oxide is integrated and it is pinched-off under the zero bias condition. As JFET diode decreases the forward voltage drop using JFET channel efficiency rather than the cell pitch reduction or the increase of doping concentration in n-SiC drift region, VF and capacitive charges which have a trade-off relationship typically could be decreased simultaneously and a better switching performance is also expected accordingly. Figure-of-Merit (=VF×QC) of the proposed JFET diode has been improved by 20.2% in average compared to that of JBS diode and this FOM would be the best in class among 1200V SiC diode products.