On the splitting of SiH absorption bands in infrared spectra of hydrogenated microcrystalline silicon

Abstract

Abstract The structure of hydrogenated microcrystralline silicon (mc-Si: H) films deposited by hot-wire chemical vapour deposition was investigated by means of X-ray diffraction (XRD) and infrared (IR) spectroscopy. Roughly random orientation of crystallites grained preferentially by (111) planes was established by XRD. The behaviour of IR absorption lines were analysed with respect to the variation in mean grain sizes and high-temperature treatments. As was established, the characteristic features of IR absorption in mc-Si: H come from the bonding of hydrogen on grain boundaries in the form of monohydrides and polyhydride groups and the splitting of absorption bands. The latter was interpreted in terms of absorption of optically anisotropic SiH monolayers covering the internal surfaces in mc-Si: H.