Deposition of silicon-doped diamond-like carbon films by plasma-enhanced chemical vapor deposition using an intermittent supply of organosilane

• The stresses of multilayer films were lower than those of single-layer films.
• Multilayer films had higher adhesion strength than single-layer films.
• Multilayer films showed better tribological properties than single-layer films.

We have deposited Si-doped DLC (Si-DLC) multilayer films by plasma-enhanced chemical vapor deposition (PECVD) using an intermittent supply of monomethylsilane (SiH3CH3; MMS) as the Si source. The mechanical and tribological properties of the multilayer films were compared with those of Si-DLC single-layer films. The internal stress decreased as the Si content increased. It was found that the internal stress values of the multilayer films were lower than those of the single-layer films. Scratch tests demonstrated that the multilayer films had higher adhesion strength than the single-layer films owing to the further reduction of the internal stress. We found that the multilayer films with low Si content presented low friction while maintaining the wear performance. Specifically, the multilayer film containing ~ 2 at.% Si showed a friction coefficient less than 0.08, while the addition of ~ 11 at.% Si to the single-layer film was required for obtaining such a low friction coefficient. The wear rate increased with increasing Si content. In the case of the above two films, the single-layer film had a specific wear about rate two times higher than that of the multilayer film.