On the hydrogen incorporation, intrinsic stress and thermal stability of hydrogenated amorphous carbon films deposited from an electron cyclotron resonance plasma

Diamond-like carbon films have been prepared by plasma enhanced chemical vapour deposition of methane at low pressure, in a dual ECR-RF glow discharge, at two different bias voltages −30 and −600 V and with different thicknesses (0.2, 0.5 and 0.8 μm). The differences in the microstructure and the intrinsic stress of the films were investigated in relationship to the H content and bonding. Annealing of the samples in vacuum at temperature up to 600°C produces changes in their structural properties and the intrinsic stress. These changes are found to be strongly dependent on the deposition conditions. The stress results, correlated with infrared, thermal desorption mass spectroscopy and elastic recoil detection analysis data show that annealing at high temperature (450–550°C) produces two different relaxation processes. A relaxation by atomic rearrangement and a reduction of the volumetric distortion in aromatic domains for the films deposited at −30 V, and a relaxation by peeling for those grown at −600 V.