Preparation of diamond-like carbon films by plasma source ion implantation with superposed pulse

Diamond-like carbon (DLC) films were deposited by a plasma source ion implantation (PSII) method on silicon wafer and 440C stainless steel substrates. Pure C₂H₂ gas was used as a working gas for plasma. The plasma was generated by an inductively coupled plasma (ICP) source with a planar coil. Two types of pulse generators connected in series were used for DLC film deposition in this study. The superposed negative voltage pulsed in the range of 3 kV to 13 kV and DC in the range of 1 kV to 4 kV were applied to a substrate holder to accelerate ions from the plasma. The surface morphology was observed by a scanning electron microscope and an atomic force microscope. The compositional and structural characterization of the films was carried out using Fourier transform infrared spectroscopy (FT-IR) and Raman spectroscopy. The hardness of the films was measured by an indentation method. The friction coefficients of the films were measured with the aid of a reciprocation sliding tester. The results showed that the all of the films were amorphous and showed typical Raman spectra of DLC films. The structure and the properties of the DLC films were changed depending on the pulse condition