Synthesis of diamond-like carbon thin film via multi pulse high-power impulse magnetron sputtering

Diamond-like carbon (DLC) thin films were prepared via a multi pulse high-power impulse magnetron sputtering (HiPIMS) at an Ar gas pressure of 0.6 Pa and an average power of 65 W. The first HiPIMS plasma temporally evolved during a pulse width of 12 μs and the discharge current reached 50 A corresponding to 1.8 A/cm². After the application of the first-pulse voltage for HiPIMS, multi-pulse voltages were applied to generate the multi pulse HiPIMS. The film structure and the film density were analyzed using the Raman spectroscopy and X-ray reflectivity (XRR) measurement. The Raman parameters, such as G peak position, intensity ratio of G band and D band, and FWHM of G band, of the films prepared by multi-pulse HiPIMS were not strongly dependent on the pulse number, but were different from those of the film prepared by single pulse HiPIMS. The film density was calculated using the XRR patterns of the prepared films with the film thickness of 60-80 nm. The estimated film density of the DLC film prepared by single pulse HiPIMS was about 2.36 g/cm³, whereas that of the films prepared by the multi-pulse HiPIMS ranged between 2.41 and 2.46 g/cm³.