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 photoelectro n spectroscopy (XPS) and synchrotron radiation ultraviolet photoelectr on spectroscopy and it is found that a large amount of nitrogen can be incorporated in the layers. The valence band structure of the oxide s urface nitrided at 25 degrees C is similar to that of Si3N4, while tha t nitrided at 700 degrees 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 inter face. (C) 1997 American Institute of Physics.