Quality of low-pressure chemical-vapor-deposited (LPCVD) oxide andN2O-nitrided LPCVD (LN2ON) oxide is investigated under high-field stress conditions as compared to thermal oxide. It is found that LPCVD oxide has lower midgap interface-state densityDit-mand smaller stress-inducedDit-mincrease than thermal oxide, but exhibits enhanced electron trapping rate and degraded charge-to-breakdown characteristics, which, however, are significantly suppressed in LN2ON oxide, suggesting effective elimination of hydrogen-related species. Moreover, LN2ON oxide shows further improvedSi/SiO2interface due to interfacial nitrogen incorporation. ©1997 American Institute of Physics.