Comparison of ultrathin SiO2 films grown by thermal oxidation in an N2O ambient with those in a 33% O2/N2 ambient

An N2O ambient allowed the oxidation rate to be substantially low while forming an oxynitride layer at the early stage of oxidation, and also provided nitrogen atoms to the oxide film during further oxidation. Both the formation of an oxynitride layer in the interface of SiO2 and Si substrate and a nitrogen incorporation in the grown oxide film were determined by wet chemical etching and x-ray photoelectron spectroscopy analysis of the grown oxide film. The electrical properties of the N2O oxide films were determined and compared with those of the oxide films grown in a pure or 33% O2/N2 ambient. The superiority in electrical properties appeared to be caused by the formation of the oxynitride layer in the interface of SiO2 and Si substrate.