Low temperature process for preparing a diamond-like-carbon film from graphite by H 2-gas chemical sputtering

Abstract

By means of hydrogen gas chemical sputtering of a graphite target, we have succeeded in the preparation of high insulating diamond-like-carbon (an a-C: H) film by RF- and DC-power. A noteworthy point is that the film can be prepared quite easily by a low temperature (room temperature ∼ 150°C) process. The film contains about 0.8 H/C of hydrogen atoms, and it is estimated that 80 or 90% of the bonding between neighbouring carbon atoms (except the C-H bond) is by a sp 3 hybridization bond. The energy gap is from 1.2 to 3.0 eV, which increases with the content of hydrogen atoms as a general tendency. The resistivity is about 10 12 Ω cm, and the density of the dangling bond is estimated to be of the order of 10 17 cm 3 . Diamond grains of about a few hundred Å in diameter appeared in the film annealed at 1000°C in vacuum.