Low Temperature Nitridation of Si Oxide Utilizing Activated Oxygen and Nitrogen

Abstract

Oxynitride or nitride films are promising materials as a substitute for silicon dioxide because of their high dielectric constant and blocking effect on B penetration. The purpose of this work is to fabricate ultrathin oxynitride films by oxidation and nitridation utilizing activated oxygen and nitrogen at a very low temperature. Secondary ion mass spectroscopy (SIMS) and X-ray photoelectron spectroscopy (XPS) analyses showed nitrogen incorporation at the surface of the oxide. A maximum nitrogen density of 9.5% was obtained at 400°C nitridation. The dielectric constant increased with increasing temperature. At 400°C, we obtained a 10% increase in the dielectric constant. Measurements of leakage currents also showed that radical nitridation of radical silicon oxide was effective. The results obtained in this study suggest that this method is very useful for improving the quality of gate oxide.