Study of the structure and phase composition of nanocrystalline silicon oxynitride films synthesized by ICP-CVD

Thin nanocrystalline silicon oxynitride films were synthesized for the first time at low temperatures (373–750 K) by inductively coupled plasma chemical vapor deposition (ICP-CVD) using gas mixture of oxygen and hexamethyldisilazane Si2NH(CH3)6 (HMDS) as precursors. Single crystal Si (1 0 0) wafers 100 mm in diameter were used as substrates. Physicochemical properties of the thin films were examined using ellipsometry, IR spectroscopy, Auger electron and X-ray photoelectron spectroscopy and XRD using synchrotron radiation (SR). The studies of the phase composition of nanocrystalline films of silicon oxynitride showed that in the case of oxygen excess in the initial gas mixture, they contain a mixture of hexagonal phases: h-SiO2 and α-Si3N4. These phases consist of oriented nanocrystals of 2–3 nm size. In case of decrease of oxygen concentration in the initial gas mixture, the fraction of the α-Si3N4 phase increases.