Evaluation of interface potential barrier heights between ultrathin silicon oxides and silicon

Interface potential barrier heights for ultrathin silicon oxides (15– 44 Å) on silicon and effective electron masses in some of these oxides are evaluated. Evaluation is performed using a new technique of analyzing the charging characteristics of metal-nitride-oxide-semiconductor capacitors. Oxides thicker than 36 Å have the same potential barrier heights as those for thick oxides, assuming the effective electron mass of the oxides is the same. However, for oxides thinner than 31 Å, the potential barrier heights decrease and the effective electron masses increase as the oxide thickness decreases. These results suggest that oxides at least thicker than 36 Å can be applied to metal-oxide-semiconductor field-effect transistors as gate oxides.