The present work shows the investigations of a-SiC(N,O):H thin films produced by d.c. plasma-enhanced chemical vapor deposition under high power conditions. In contrast to the traditional process we use liquid precursors (hexamethyldisiloxane, hexamethyldisilazane) diluted in argon or nitrogen for decomposition in the glow discharge. Films were analysed by different methods with regards to their composition and structure (electron probe microanalysis, X-ray photoelectron spectroscopy, glow discharge optical emission spectroscopy, infrared spectroscopy).