Improved interfacial properties of SiO2 grown on 6H-SiC in diluted NO

The interface quality and reliability of gate oxides grown on n-/p-type 6H-SiC in diluted NO gas at 1150 degrees C are investigated. As compared to conventional 100%-NO oxidation, the diluted-NO (50% and 23%) oxidations lead to lower interface-state, border-trap and oxide-charge densities. This is attributed to the fact that carbon-accumulation and carbon-removal rates are closer when oxidation is performed in diluted NO, giving a smoother, less disordered and strained interface. Moreover, less degradation of the diluted-NO samples than 100%-NO samples is observed during high-field stressing ( +/-7 MV/cm), indicating that stronger Si = N bonds are created near/at the SiC/SiO2 interface for oxide grown in diluted NO ambient.