Free carrier density enhancement of 4H-SiC Si-face MOSFET by Ba diffusion process and NO passivation

Field effect mobility was improved in a 4H-SiC (0001) metal-oxide-semiconductor field-effect transistor with Ba diffusion into the gate oxide and NO passivation. The Ba diffusion process caused Ba interface passivation, which suppressed oxide surface roughening. Free carrier mobility and free carrier density were evaluated through Hall effect measurements using the Van der Pauw technique at room temperature. Passivation by Ba or NO was found to have no effect on free carrier mobility but contributed to increased free carrier density. A free carrier ratio of up to 70% was achieved through combined Ba diffusion and NO passivation.