Influence of pulse conditions on the properties of DLC films prepared by plasma source ion implantation

Diamond-like carbon (DLC) films were deposited by plasma source ion implant ation (PSII) on silicon wafers and 440C stainless-steel substrates. Acetyle ne (C2H2) gas was used as a working gas for the plasma. Radio frequency pow er was used to produce a glow discharge plasma, Negative voltage pulses in the range of I kV to 20 kV were applied to a substrate holder to accelerate ions from the plasma. The surface morphology was observed using an atomic force microscope. Structural information on the DLC films was obtained by R aman spectroscopy. Hardness of the films was measured by an indentation met hod. The results showed that the surface roughness varied with the applied pulse bias voltage. A smooth surface was obtained at a pulse voltage of 5 t o 20 kV. The Raman spectra were divided into the "D" disordered peak and "G " graphitic peak, The integrated intensity ratio of the "D" peak to the "G" peak, l(D)/l(G), increased at a high voltage. Relatively high hardness was obtained For the DLC films prepared at 5 to 20 kV.