Improved implanted RESURF MOSFETs in 4H-SiC

High voltage switches suitable for integration with low-voltage logic gates form a basic building block for power integrated circuits. Previously, we demonstrated self-isolated lateral MOSFETs (Chatty et al, 1999) in 4H-SiC which blocked a drain voltage above 1200 V with an on-resistance of 4 /spl Omega/cm/sup 2/. In order to prevent breakdown at the gate edge, the devices required a thick gate oxide (900 nm) and hence very high gate drive voltages. In this work, we report a systematic study of lateral RESURF MOSFETs with reasonable (200 nm) gate oxide thickness that block above 900 V and have an on-resistance of 0.56 /spl Omega/cm/sup 2/. These devices have phosphorus implanted source/drain and nitrogen implanted RESURF regions as proposed in an earlier paper (Chatty et al, 1999). The maximum power handling capability V/sub B//sup 2//2R/sub ON/ is calculated to be 720 kW/cm/sup 2/, 4 times higher than the previously reported device.