Published online by Cambridge University Press: 21 February 2011
A series of amorphous silicon/carbon films were deposited from an RF glow discharge in silane-phenylsilane feed gas mixtures with the (ΦSiH3 content varying from 0 to 100 %. The films were characterized with optical and electrical measurements. While the structure of the films deposited from the mixtures contains carbon in more than one configuration the amount of pendant phenyl groups increases as the phenylsilane content of the feed gas is increased. The optical gap, derived from Tauc plots of the absorption spectra, ranges from 1.7 to 2.9 eV, while the refractive index obtained from ellipsometry, ranges from 3.7 to 1.8. The optical gap was found to vary linearly with the carbon atomic fraction in the feed gas, independent of the configuration of carbon atoms in the solid. The refractivity, (n2− 1)/(n2 + 2) , was found to exhibit a similar composition dependence. The room temperature resistivity was observed to increase sharply with increasing carbon content, rising from 107 ohm-cm to 1016 ohm-cm as the ΦSiH3 content of the feed gas was increased from 0 to 25 per cent.