Nitridation of silicon oxide layers by nitrogen plasma generated by low energy electron impact

Low temperature nitridation of silicon oxide layers by nitrogen plasma generated by electron impact is investigated using x-ray photoelectron spectroscopy (XPS) and synchrotron radiation ultraviolet photoelectron spectroscopy and it is found that a large amount of nitrogen can be incorporated in the layers. The valence band structure of the oxide surface nitrided at 25 °C is similar to that of Si3N4, while that nitrided at 700 °C resembles the mixture of silicon oxide and silicon oxynitride. Measurements of XPS depth profiles show that the nitrogen concentration is high near the surface and the oxide/Si interface.