Effects of NH3 nitridation on the chemical and electrical properties of N2O oxides have been studied. Compared with NH3-nitrided SiO2, NH3 nitridation does not degrade the electrical properties of N2O oxides, thus resulting in superior impurity diffusion barrier properties, while preserving excellent interface immunity to hot-carrier injection and much lower charge trapping. Correlation studies between the chemical and electrical properties of NH3-nitrided N2O and NH3-nitrided SiO2 have been done to explain these results.