Effects of source gases on the properties of silicon/nitrogen-incorporated diamond-like carbon films prepared by plasma-enhanced chemical vapor deposition

We have deposited silicon/nitrogen-incorporated diamond-like carbon (Si-N-DLC) films by plasma-enhanced chemical vapor deposition using dimethylsilane [SiH2(CH3)2; DMS] and N2 as the Si and N sources, respectively. We compared the properties of the Si-N-DLC films with those of the film prepared using hexamethyldisilazane [((CH3)3Si)2NH; HMDS] as the Si/N single source. There was little difference in the Si and N fractions between the Si-N-DLC (DMS + N2) film prepared at a N2 flow ratio of 6.81% and Si-N-DLC (HMDS) film deposited at a HMDS flow ratio [HMDS/(HMDS + CH4)]of 2.27%. It was found that the internal stress of the Si-N-DLC (DMS + N2) film was lowered compared with that of the Si-N-DLC (HMDS) film. The Si-N-DLC films showed much higher adhesion strength than a pure DLC film. We found that the Si-N-DLC (DMS + N2) film had lower friction and higher wear resistance than the Si-N-DLC (HMDS) film. The wear rate of the Si-N-DLC (DMS + N2) film was nearly as low as that of the pure DLC film.