Microstructural study of mechanical and thermal properties of diamond-like carbon

This paper describes the microstructural study of a chemical vapor deposited diamond-like carbon (DLC) thin film, ranging the thickness from 1 mu m to 1.36 mu m. The effect of deposition condition on the microstructure of the DLC film was analyzed by Raman spectroscopy. Increasing the bias voltage and the discharge current shifted the peak shift of G band toward high frequency and enlarged I(D)/I(G) ratio. Lower density films were obtained by lowering bias voltage at discharge current of 5A, but conversely higher density films by lowering bias voltage at 10A and 20A. The hardness and Young's modulus were directly proportional to density of the film. Molecular dynamics analyses gave a linear relationship between the bonding ratio, density and Young's modulus of the film. These analytical results qualitatively agreed with the experimental results. The thermal conductivity of the DLC films was discussed based on the molecular dynamics results.