High Channel Mobility in Inversion Layer of SiC MOSFETs for Power Switching Transistors

Abstract

A high channel mobility in inversion layers of 4H- and 6H-SiC metal-oxide-semiconductor field-effect-transistors (MOSFETs) was successfully achieved by using the (1120) face instead of the conventional (0001) Si-face. For 4H-SiC, the channel mobility on the (1120) face (95.9 cm²/Vs) was dramatically improved to be 17 times higher than that on the (0001) face (5.6 cm²/Vs). For 6H-SiC, the channel mobility on the (1120) face (115.7 cm²/Vs) was also improved to be 2.5 times higher than that on the (0001) face (44.8 cm²/Vs). These results suggest that the MOS interface quality on the (1120) face is superior to that on the (0001) face. In the case of the (0001) face, 15R-SiC MOSFETs showed a higher channel mobility (59.2 cm²/Vs) than 6H-SiC, due to a higher bulk mobility in 15R-SiC than 6H-SiC.