On the microstructural, optical and mechanical properties of hydrogenated amorphous carbon films deposited in electron cyclotron resonance plasma

Hydrogenated amorphous carbon (a-C:H) films have been prepared from methane -argon (5%) gas mixture in a dual electron cyclotron resonance radio freque ncy (ECR-r.f.) glow discharge assisted plasma system. The way in which the optical properties and the residual stresses are related to the mu m micros tructure was systematically analysed in the as-deposited samples, as a func tion of the self-bias applied to the substrate, ranging from -30 to -600 V. Combined infrared absorption and elastic recoil detection analysis experim ents, were used to characterize the vibrational properties and the H conten t, while optical transmission measurements were employed to determine the o ptical parameters such as the refractive index (It) and the optical gap E-0 4. These results are correlated with the residual stress measurements. A go od correlation is observed between the variation of E-04 and n and the chan ges in the total H bonded and content, as a function of the self-bias appli ed to the substrate. Moreover, the residual stress is found to be compressi ve and increases with the bias until it reaches a maximum at - 120 V, and t hen decreases monotonically for higher bias. This behaviour, which is affec ted not only by the [H]/[C] ratio but also by the C-H and C-C volumetric di stortions, can be explained partially by the subimplantation model. (C) 200 0 Elsevier Science S.A. All rights reserved.