Characteristics 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 radio-frequency plasma-enhanced chemical vapor deposition (PECVD) using methane (CH ₄), argon (Ar), and hexamethyldisilazane {[(CH ₃) ₃Si] ₂NH} as the Si and N source, and investigated the structure and the mechanical and tribological properties of the films. We compared the properties of the Si-N-DLC films with those of the Siincorporated DLC (Si-DLC) films prepared by PECVD using monomethylsilane (CH ₃SiH ₃) as the Si source. It was found that the N incorporation together with Si into DLC was effective in further decreasing the internal stress and increasing the adhesion strength. The friction coefficients of the Si-N-DLC films containing 4.0% N or less were as low as those of the Si-DLC films. We also found that the Si-N-DLC film containing 10.0% Si and 4.0% N had a higher wear resistance than the Si-DLC film containing 10.8% Si. The wear rate was comparable to that of the undoped DLC film.