Infrared absorption and x‐ray photoelectron spectroscopy studies of the anodic oxidation of plasma silicon nitride

Silicon oxide films have been grown by anodic oxidation of plasma enhanced chemically vapor deposited silicon nitride films onto silicon substrates. Infrared absorption and nuclear reaction analysis (NRA) of the films reveals that during the anodic oxidation the nitrogen of the silicon nitride films is lost to electrolyte/oxide interface. These analyses combined with x‐ray photoelectron spectroscopy analysis show that the final oxide structure is formed by an outer silicon dioxide layer followed by the inner layer of the previously deposited silicon nitride. In the case of thicker oxides the silicon dioxide layer is followed by a region made of a mixture of SiO₂ and SiN_x molecules. The elementary reactions as well as the ionic transport through the interface is discussed.