In this work is presented a detailed physicochemical, structural and optical
characterization of SiOxNy thin films. The films deposited using PECVD
in SiH4-N2O-He discharges were thermally annealed at 1273 K for 1 hour
in ambient nitrogen. The film stochiometry was measured by Rutherford
Backscattering Spectroscopy. The chemical composition was dominated by
silicon suboxide containing some Si-N and Si-H bonds. Raman scattering measurements
suggest the formation of nanocrystallite silicon in the annealed films. The
Raman observation is strongly supported by Transmission Electron Microscopy
analysis which shows a high density of silicon nanocrystals, having a mean
radius ranging between 3 and 6 nm. Using Spectroscopic Ellipsometry, we
discussed the dielectric function evolution as a function of the deposition
parameters.