Stress and structural properties of diamond-like carbon films deposited by electron beam excited plasma CVD

Diamond-like carbon (DLC) films prepared using CH4, or C6H6 with varying deposition parameters by an electron beam excited plasma CVD system were investigated for the internal stress, dynamic hardness and structural properties such as the film density, total, bonded and unbound hydrogen contents, sp(3) ratio and graphite crystallite. From the correlations between internal stress and structural properties, the following conclusions were derived. The fraction of unbound hydrogen to total hydrogen content was the most influential factor for the compressive stress of the DLC films deposited from CH,. It is suggested that unbound hydrogen may be trapped into the disordered microstructure of graphite crystallites embedded in the network of film. For the DLC films deposited from C6H6, it was shown that the compressive stress was correlated with not only the fraction of unbound hydrogen content but also the degree of cross-linking between graphite crystallites in the film. (C) 2002 Elsevier Science B.V. All rights reserved.