4H-SiC BJT and Darlington switch for power inverter applications

In this paper, the temperature coefficient of 4H-SiC NPN BJT current gain is studied by performing two-dimensional numerical simulations with the ISE SiC TCAD module. It is shown that, depending on the carrier lifetime and base doping level, 4H-SiC NPN BJTs with Al-doped base could have both PTC and NTC. We report the fabrication of a 4H-SiC BJT with an NTC in current gain, a current gain of β=9 and a BVceo of 800 V. We also report the first demonstration of packaged 4H-SiC power BJTs operating in an all-SiC inductively-loaded half-bridge inverter up to 8.8 kW and the first demonstration of a 4H-SiC Darlington switch as well as its performance in an inductively-loaded half-bridge inverter.