Carbon 1s and silicon 2p X-ray photoelectron spectra of phenylsilane plasma polymer films prepared at substrate temperatures,Ts, between 50 and 450°C were recorded. The binding energies, lineshapes, and shake-up satellite intensities are in accordance with a structure consisting of a silicon network with pendant phenyl groups, and the minor dependence on Ts is consistent with the main effect of increasing preparation temperature being the loss of hydrogen and some pendant phenyl, with a concurrent increase in the interconnectivity of the network. The observed C 1s binding energy and linewidth specifically rule out the presence of any significant amount of carbon in silicon carbide form. A simultaneous shift of about 0.6 eV in the binding energies of both the C 1s and Si 2p lines is tentatively interpreted as a shift in the Fermi level with respect to the valence band edge. © 1984.