Mechanical properties of a-C:H thin films deposited by r.f. PECVD method

Internal stress, hardness and deposition rate were evaluated for hydrogenated amorphous carbon (a-C:H) films prepared by conventional r.f. plasma-enhanced chemical vapour deposition. The internal stress, hardness and deposition rate of 0.9, 18 and 58 nm/min, respectively, achieved at 40 Pa gas pressure for negative self-bias voltages (V-b) window (from -370 to -550 V). It was found that the negative self-bias voltage window was associated with the existence of two turning points, which shift to higher wavenumber of G band peak position of Raman spectroscopy (Raman) at different V-b in relation to the internal stress and hardness, and rapid decreasing of the relative total peak areas of Fourier Transform Infra-red absorption spectroscopy (FT-IR). The internal stress relaxed from approximately 35 eV ion energy when the energy is increased and rapidly decreased in comparison with the stress relaxation equation. (C) 2004 Elsevier Ltd. All rights reserved.