Impact of channel mobility improvement using boron diffusion on different power MOSFETs voltage classes

SiC planar VDMOS of three voltages ratings (1.7 kV, 3.3 kV and 4.5 kV) have been fabricated using a Boron diffusion process into the thermal gate oxide for improving the SiO
₂
/SiC interface quality. Experimental results show a remarkable increase of the effective channel mobility which increases the device current capability, especially at room temperatures. At high temperatures, the impact of the Boron treatment is lower since the major contribution of the drift layer to the on-resistance. In addition, the intrinsic body diode characteristics approximate to that of an ideal PiN diode, and the blocking capability is not compromised by the use of Boron for the gate oxide formation.