Isotopic Effects in a-C:(H/D) Films Deposited from Methane/ Hydrogen RF Plasmas

Hard amorphous hydrocarbon films have been deposited by RF glow discharges in methane/hydrogen mixtures with different hydrogen isotopes. For CH 4 + D 2 and CD 4 + H 2 gas mixtures, the film growth rate, the density, the refractive index, and the isotopic hydrogen content are obtained as functions of the process gas composition. Further, the hydrogen loss induced by 15 keV helium ions is studied. The results are qualitatively interpreted in terms of different effects of ion bombardment during film deposition which influence the properties of the resulting films.