Synthesis of a-C thin films by plasma-based ion implantation using an electron cyclotron resonance plasma source with a mirror field

Diamond-like carbon (DLC) films were synthesized by the plasma-based ion implantation technique, and the influence of the raw material used and the duty ratio of the pulse bias to the target on the properties of the DLC films was investigated. DLC films prepared by applying a pulse bias with a low duty ratio using either CH4 or C2H2 gas showed a good tribological property. A CH absorption band measured by Fourier transform infrared absorption spectroscopy was not observed within the detection limit in the DLC films formed using CH4 gas with the application of a pulse bias of a low duty ratio, but it was in the DLC films formed using C2H2 gas. On the other hand, according to elastic recoil detection analysis, the hydrogen content remaining in the film formed using CH4 gas was more than that remaining in the film formed using C2H2 gas. We assume that hydrogen atoms remaining in the film formed using CH4 gas were not bonded with carbon atoms and existed in the interstitial site in the film. We consider that these differences of the properties of the DLC films formed using CH4 or C2H2 gas resulted from the difference of the thickness of the modified carbon layer by the application of a pulse bias.