Improved Inversion Channel Mobility in 4H-SiC MOSFETs on Si Face Utilizing Phosphorus-Doped Gate Oxide

We propose a new technique for fabricating 4H-SiC metal-oxide-semiconductor field-effect transistors (MOSFETs) with high inversion channel mobility. P atoms were incorporated into the SiO₂/4H-SiC (0001) interface by postoxidation annealing using phosphoryl chloride (POCl₃). The interface state density near the conduction band edge of 4H-SiC was reduced significantly, and the peak field-effect mobility of lateral 4H-SiC MOSFETs on (0001) Si face was improved to 89 cm²/V · s by POCl₃ annealing at 1000°C.