Optimizing the Thermally Oxidized 4H-SiC MOS Interface for P-Channel Devices

Optimization of the thermally oxidized 4H-SiC MOS interface has produced p-channel lateral MOSFETs with hole inversion layer mobility as high as 10 cm2/Vs. This has been accomplished by identifying the 1200oC Dry, 950oC Wet (un-nitrided) oxidation as ideal for hole conduction across the MOS inversion layer and by implant activation annealing at 1800oC of the heavily implanted n-type well. High temperature measurements show that the high mobility and normally-off operation is maintained throughout the operating temperature range. Oxide leakage measurements yield a dielectric strength of 8.5 MV/cm with 90% yield, thereby enabling the manufacture of high performance p-channel devices like the IGBT.