Phenylsilanes were deposited by r.f. glow discharge to investigate the relationship between the synthesis conditions (r.f. power, synthesis time and monomer) and the structure and morphology of plasma-polymerized films. The film deposited at 2.0 W consisted of polycarbosilane-like main chains and side chains corresponding to the monomer structure. The film deposited at higher r.f. power consisted of a polycarbosilane-like main chain with more cross-links and less aromatic groups. The films synthesized at 2.0 W from phenylsilane had many submicrometre sized particles on the surface, but the films synthesized from phenylsilanes with methyl groups had few particles and smooth surfaces. The films deposited at higher r.f. power had many particles on their surfaces. The infrared spectra of methylphenylsilane polymer films were independent of the synthesis time, but film surface morphology changed from a smooth surface into a granular surface with an increase in the synthesis time.