The electrical properties of nitrided silicon dioxide formed by reactive sputtering in Ar/O2/N2plasma from the SiO2target have been studied. The nitrogen mixing ratio was varied from 0% to 15%, with the argon mixing ratio kept at 80%. It is found that as more nitrogen is incorporated, the leakage current increases for electron injection from both aluminum and silicon. By nitrogen reactive sputtering, the interface states generation during constant current stress is greatly reduced in comparison with oxide sputtered in only an Ar/O2gas mixture. A mixture ratio of Ar/O2/N2equal to 80:15:5 is found to give optimum oxide quality with good resistance to interface states generation and low leakage current. ©1995 American Institute of Physics.