DLC (Diamond-like Carbon) classified in new materials is amorphous carbon including hydrogen and has the similar property to diamond. DLC film was formed by the ion beam evaporation method in the early 1970's, and after that has been manufactured by various methods. Because the representative property of DLC shows the high hardness and low friction coefficient, DLC is applied in various fields such as motor parts or tools.

In this study, mechanical properties of Si-DLC thin films were investigated as the purpose of performing lower friction coefficient. DLC thin films were prepared by using He⁺ or Ar⁺ ion beam in a C₁₂H₂₆ atmosphere. In this experiment, the conditions of He⁺ or Ar⁺ ion beam was changed with various current densities and accelerating voltages. Si-doped DLC thin films were prepared by simultaneously using ion beam irradiation and Si evaporation in a C₁₂H₂₆ atmosphere. Si concentration in DLC was changed by control of a Si evaporation rate. Film composition and microstructure were investigated by X-ray photoelectron spectroscopy and Raman spectroscopy. The hardness was measured from an indentation method with a Knoop indenter. The friction coefficient was measured for an SUJ2 ball with a constant load of 0.98 N until the sliding distance reached to a length of 10 or 100 m.              

The mechanical properties for Si-DLC thin films were exhibited in this experiment. Friction coefficient of the Si-DLC thin film with Si deposition rate of 0.04 nm/sec at accelerating voltage of 5 kV showed 0.08 at a sliding distance of 100 m. The properties of this film with about 30 % in Si concentration were performed by the SiC formation and ion beam modification in the interface between the film and the substrate.