SiN x and diamond-like carbon (DLC) films were prepared simultaneously on Si substrates by the RF magnetron sputtering of a silicon nitride (Si3N4) target and the filtered cathodic arc (FCA) deposition of graphite, respectively. The RF power was fixed at 100 W, while the arc current of graphite for the FCA deposition was varied from 20 to 80 A. The structure of composite SiN x /DLC films was investigated by Raman spectroscopy. The chemical composition and chemical state of the films were analyzed by X-ray photoelectron spectroscopy (XPS). Results revealed that the atomic concentration of carbon (C) increased, while those of silicon (Si) and nitrogen (N) decreased with increasing arc current. In addition, the sp3 content in the composite films was found to increase with the arc current. This result indicates that the structure and property of the composite films can be controlled according to their required applications by varying the arc current.

Composite SiN x /DLC films were deposited on Si substrate by RF magnetron sputtering of silicon nitride (Si 3 N 4 ) target simultaneously with filtered cathode arc (FCA) of graphite. The RF power was fixed at 100 W whereas the arc currents of FCA were 20, 40, 60 and 80 A. The effects of arc current on the structure, surface roughness, density and mechanical properties of SiN x /DLC films were investigated. The results show that the arc current in the studied range has effect on the structure, surface roughness, density and mechanical properties of composite SiN x /DLC films. The composite SiN x /DLC films show the sp 3 content between 53.5% and 66.7%, density between 2.54 and 2.98 g/cm 3 , stress between 1.7 and 2.2 GPa, and hardness between 35 and 51 GPa. Furthermore, it was found that the density, stress and hardness correlate linearly with the sp 3 content for composite SiN x /DLC films.