Preparation of sp3-Rich Amorphous Carbon Film by Hydrogen Gas Reactive RF-Sputtering of Graphite, and Its Properties

An a-C:H film was prepared for the first time by H2 gas reactive rf-sputtering of a graphite target onto low temperature (room temperature ∼150°C) substrate. This film has a uniform amorphous structure and an H-atom ratio of 0.8 H/C; its electrical resistivity was 106∼1012 Ωcm. Vickers' hardness number of the film was 1000∼2000. IR, Raman and ESCA spectra showed that the bonding between the neighbouring C-atoms was for the most part by sp3 bond, and that sp2 bond was rare. Approximately 200 Å of diamond grains were observed by TEM in annealed film at 1000°C, and verified by electron diffraction pattern.