Oxygen-assisted structural transformations in silicon polycrystalline films

Using IR-spectroscopy, electron microscopy, profilometry and Rutherford backscattering technique, the oxygen structural arrangement in silicon polycrystalline films with different oxygen contents was investigated. Si-O-Si bond angles were estimated and contribution of different Si-O-y- Si4-y (1 less than or equal to y less than or equal to 2.) clusters to the film lattice was determined. Predominant content Of SiO3Si and SiO4 units was shown to exist. Such an effect of oxygen agglomeration was proved experimentally and was explained by enhanced oxidation of silicon grains during the film fabrication. Results of atomic structure simulation for Si grain boundaries using Molecular Dynamics method agree with this observation rather well.