Comparison in structure and property of carbon films produced by various plasmas

For carbon coating films produced by RF plasma in the plasma CVD apparatus, the film properties such as crystal structure, chemical bond, hardness, depth composition profile and hydrogen concentration were examined. The relation of the film properties with plasma parameters was also studied. The structure of carbon film became amorphous when the electron temperature was relatively lower. However, the graphite type structure was obtained for a case with higher electron temperature and higher plasma potential. When the structure changed to graphite one, the hydrogen concentration decreased from 40% to 5% and the knoop hardness increased from 80 to 500 kg/mm2. The carbon films produced by RG discharge (TEXTOR), DC glow discharge (Heliotron-E), ECR plasma CVD (RIKEN) and Electron Beam Evaporation (EBE, Hokkaido Univ. were similarly analyzed. The film structure was a mixture type of amorphous and graphite states for ECR discharges, graphite type for EBE and amorphous type for Heliotron-E. For these films, it was also observed that the hydrogen concentration decreased as the structure changed from amorphous carbon to graphite. (author). 11 refs.; 6 figs