Deposition of silicon-containing diamond-like carbon films by plasma-enhanced chemical vapour deposition

Abstract

Silicon-containing diamond-like carbon (Si-DLC) films were prepared on silicon wafer substrates by DC glow discharge. Acetylene and mixture with tetramethylsilane gases were used as working gases for the plasma. A negative DC voltage was applied to the substrate holder. The DC voltage was changed in the range from − 1 kV to − 4 kV. The surface morphology of the films and the film thickness were observed by scanning electron microscopy. The compositions of the Si-containing DLC films were examined by X-ray photoelectron spectroscopy. The film structure was characterized by Raman spectroscopy. A ball-on-disc test with 2 N load was employed to obtain information about the friction properties and sliding wear resistance of the films. The films were annealed at 723 K, 773 K and 873 K in ambient air for 30 min in order to estimate the thermal stability of the DLC films. The surface roughness of the Si-containing DLC films was very low and no special structure was observed. The deposition rate increased linearly with Si content. The positions of D- and G-bands in Raman spectra decreased with Si content. The integrated intensity ratios I D/ I G of the Si-containing DLC films decreased with Si content. A very low friction coefficient of 0.03 was obtained for a 24 at.% Si-containing DLC film. The heat resistivity of DLC films can be improved by Si addition into the DLC films.