Structure and mechanical properties of Ag-incorporated DLC films prepared by a hybrid ion beam deposition system

Ag-incorporated diamond-like carbon films were prepared on Si(100) wafers using a hybrid deposition system composed of an end-Hall-type hydrocarbon ion gun and a silver DC magnetron sputter source. The Ag concentration in the films was controlled by changing the fraction of Ar in the Ar and benzene reaction gas. The chemical composition, microstructure, atomic bond structure, and mechanical properties were investigated for Ag concentrations ranging from 0 to 9.7 at.%. When the Ag concentration was 0.1 at.%, the Ag atoms were fully dissolved in the amorphous carbon matrix without forming any second phase. Amorphous and crystalline silver particles appeared when the Ag concentration was 1.7 and > 6.8 at.%, respectively. It was found that the hardness was not sensitive to the Ag concentration in this concentration range. On the other hand, the residual compressive stress was strongly dependent on the chemical state of the incorporated Ag atoms. The mechanical properties are discussed in terms of the changes in the microstructure and atomic bond structure induced by Ag incorporation