Evaluation of high-voltage 4H-SiC switching devices

In this paper, the on-state and switching performance of 4H-SiC UMOSFETs, TIGBTs, BJTs, SIThs, and GTOs with voltage ratings from 1 to 10 kV are simulated at different temperatures. Comparison with silicon devices highlights the advantages of SiC technology. SiC BJTs suffer the same problem as Si BJTs, namely the degradation of current gain with increased voltage rating which makes them unsuitable for applications above 4 kV. SiC MOSFETs dominate applications below 4 kV for their attractive conduction performance and advantages such as ease of use. Above 3 kV, SiC MOSFETs are not as attractive as SiC bipolar devices because of their high on-state voltages. In the voltage range simulated, SiC IGBTs, SIThs, and GTOs have comparable current handling ability. Considering the GTOs slow switching speed and drive complexities, IGBTs and SIThs are a better choice in the voltage range 4-10 kV. Calculations based on conduction loss and switching loss indicate that SiC SIThs are superior to IGBTs except in high-temperature and high-frequency applications where IGBTs are better. The need to provide a large gate current during turnoff and turn-off failure caused by gate debiasing, decreases the attractiveness of the SITh.