Hydrogenated microcrystalline silicon-carbon (muc-Si1-xCx:H) films have been grown in a plasma enhanced chemical vapour deposition system from silane-methane gas mixtures highly diluted in hydrogen. The effects of RE power, hydrogen dilution and substrate temperature on muc-Si1-xCx:H properties have been investigated. The increase in RE power reduces the average crystallite size of Si, enhances the carbon fraction, C/(C + Si), and causes a decrease in dark conductivity. The hydrogen dilution ratio R, [H-2]/([SiH4]+[CH4]), strongly affects the structure of the films. For R<100 the hydrogenated silicon-carbon films are amorphous, while for Rgreater than or equal to100 the alloys are microcrystalline. Under suitable deposition conditions muc-Si1-xCx:H films can be grown in the substrate temperature range of 200-400 degreesC. (C) 2003 Elsevier B.V. All rights reserved.