FTIR and XPS investigations of a-SiO_xN_y thin films structure

Abstract

Amorphous silicon oxynitride (a-SiOxNy) thin films with large composition variation were deposited by reactive sputtering. Their structural study was carried out by mean of FTIR and XPS analysis. The IR absorption peak maximum was found to shift towards higher wavenumbers as the oxygen content increases and the absorption peaks of Si-O and Si-N bonds also appear. The Si 2p photoelectron peak was decomposed considering five tetrahedra of SiOvN4-v (where v = 0, 1, 2, 3 and 4) following the Random Bonding Model (RBM). But the comparison between RBM theoretical and experimental predictions and the non-linear behaviour of the modified Auger parameter (α) showed that the a-SiOxNy structure can be well described only considering a mixture of SiO2, Si3N4 and SiOxNy phases.