The atomic-scale compositional depth profiling of oxynitride/Si interface by applying the maximum entropy concept to the angle-resolved Si 2p, photoelectorn spectra was performed after eliminating the effect of photoelectron diffraction on the Si 2p photoelectron spectra arising from Si substrate for oxynitride films containing the maximum nitrogen concentration of 3 and 6 at.% at the SiO2/Si(100) interface. Although the distribution of intermediate oxidation states of Si depends on the amount of nitrogen atoms incorporated at the interface, total amount of intermediate oxidation states of Si does not depend on the nitrogen atoms incorporated at the interface. (C) 2002 Published by Elsevier Science B.V.