A Hybrid-Channel Injection Enhanced Modulation 4H-SiC IGBT Transistors With Improved Performance

Conventional planar- and trench-gate silicon carbide insulated-gate bipolar transistors (SiC C-IGBT and T-IGBT) suffer from higher turn- OFF loss ( ${E}_{\text {off}}$ ) and ON-state voltage drop [ ${V}_{\text {ce(sat)}}$ ]. An improved hybrid-channel injection enhanced modulation 4H-SiC IGBT (HC-IGBT) is proposed and investigated to overcome these shortcomings in this article. The proposed IGBT structure is considered 3-D because the gate wraps around a raised emitter-to-collector channel, instead of residing on top of the channel in the conventional 2-D planar-gate structure. Therefore, multiple gates are ganged together through the same gate electrode to enable more electrons in the “ON” state and provide more path to remove extra holes in the “OFF” state. Comparing with C-IGBT and T-IGBT structure, HC-IGBT gains an improvement of 108% and 21% in a differential specific ON-resistance as well as a turn- OFF loss reduction of 11% and 16%. The industrial figure of merit (IFOM $= {V}_{\text {ce(sat)}}\,\,\times \,\,{E}_{\text {off}}$ ) of HC-IGBT is reduced by 21% and 22% compared with C-IGBT and T-IGBT, respectively. Meanwhile, the Baliga’s figure of merit (BFOM $= {V}_{\text {BR}}^{{2}}/{R}_{\text {on,sp}}$ ) shows about 63% and 15% larger than that of C-IGBT and T-IGBT. These results show that HC-IGBT structure has much superior tradeoff between the ON-state voltage drop and turn- OFF loss, indicating the potential for ultrahigh-voltage power electronic of the future.