A 475-V high-voltage 6H-SiC lateral MOSFET

High-voltage lateral MOSFET's on 6H- and 4H-SiC have been fabricated with 4 00-475 V breakdown voltage using the RESURF principle. An MOS electron inve rsion layer mobility of about 50 cm(2)/V-s is obtained on 6H-SiC wafers. Th is mobility is high enough such that the specific on-resistance of the 6H-S iC MOSFET's (similar to 0.29-0.77 Ohm-cm(2)) is limited by the resistance o f the drift layer, as desired, However, the implanted drift layer resistanc e is about ten times higher than expected for the implant dose used. Design and process changes are described to decrease the on-resistance and increa se the breakdown voltage. For 4H-SiC, extremely low mobility was obtained, which prevents satisfactory device operation.