X-ray photoelectron spectroscopy study of the chemical structure of thermally nitrided SiO2

Abstract
X‐ray photoelectron spectroscopy has been used to study the composition of 100‐Å thermally grown SiO2 films that have been thermally nitrided in ammonia. The SiOxNy/Si interface was studied both by chemical depth profiling of the oxynitride and by removal of the Si substrate with XeF2. It is found that N is distributed throughout the film, but with the concentration higher at the surface and in a region centered 25 Å from the film/substrate interface. The interface region itself is found to be oxygen‐rich relative to the rest of the film. Possible models which can explain these results are discussed.