We have deposited Si-incorporated diamond-like carbon (DLC) films by radio-frequency plasma-enhanced chemical vapor deposition using methane, argon, and monomethylsilane (MMS; CH 3 SiH 3 ) as a silicon source, and have investigated the structural and mechanical properties of the films. The deposition rate and Si atomic fraction [Si=ðSi þ CÞ] in the DLC films increased with increasing MMS flow ratio. The Si fraction was approximately 13% at a MMS flow ratio [MMS=ðMMS þ CH 4 Þ] of 3%, showing that the deposition using a combination of CH 4 and MMS produces films with high Si content compared with those deposited using conventional C and Si sources. The Si fraction was also found to increase with a decrease in Ar flow rate under a constant MMS flow ratio. Many particles composed mainly of Si, whose size was 0.3 -1 mm in diameter, were observed on the surface when deposition was carried out at MMS flow ratios of 15 and 30%. Compressive internal stress in the films decreased with the MMS flow ratio and/or with the Ar flow rate. The decrease in internal stress is probably due to the relaxation of a three-dimensional rigid network by the formation of Si-C and Si-H bonds in the films as well as Ar þ ion bombardment.

We have deposited diamond-like carbon (DLC) films by plasma-enhanced chemical vapor deposition using CH 4 and Ar gases, and have investigated the structure, chemical bonding, adhesion strength, and tribological properties of the deposited films. The film properties have been characterized by visible Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), scratch tests, and ball-on-plate friction tests. The fraction of sp 3 C-C and C-H bonds in the deposited films, as estimated from C 1s-XPS peaks, decreased with increasing substrate bias voltage. Raman analysis showed that the structural ordering of the films was induced by increasing the substrate bias voltage. The intensity of the band in the sp 3 -CH 3 stretching in the deposited films decreased with the substrate bias voltage. When the Ar-flow rate was increased, the Ar sputter etching and structural ordering of the films were encouraged. As the bias voltage was increased, the critical load determined by conducting scratch tests and the wear resistance of the films increased.

We have deposited Si-incorporated diamond-like carbon (DLC) films by radio-frequency plasma-enhanced chemical vapor deposition using methane, argon, and organosilanes, and investigated the effects of Si source gas (monomethylsilane, dimethylsilane) and substrate bias (negative dc bias, negative pulse bias) on the structure and the mechanical and tribological properties of the films. The Si-DLC films deposited using monomethylsilane as a Si source gas tended to have a higher Si atomic fraction ratio [Si=ðSi þ CÞ] than the films deposited using dimethylsilane. Friction coefficient and internal stress decreased by the incorporation of Si into the films. However, many particles composed mainly of Si were observed on the film surfaces when deposition using a dc bias was carried out at higher monomethylsilane or dimethylsilane flow ratios. It was found that for both the Si source gases, the use of a pulse bias was effective in suppressing the formation of particles and further decreasing friction coefficient and internal stress. Additionally, the pulse-biased Si-DLC films were found to have a higher wear resistance than the dc-biased Si-DLC films.