Structure and Mechanical Properties of W Incorporated Diamond-like Carbon Films Prepared Prepared by a Hybrid Ion Beam Deposition Technique

Ai-Ying Wang, Kwang-Ryeol Lee, Jae-Pyoung Ahn, Jun Hee Han
 

WC-C nanocomposite films were prepared on silicon (100) wafers using a hybrid deposition system composed of an end-Hall-type hydrocarbon ion gun and a tungsten DC magnetron sputter source. The W concentration in the films was controlled by changing the fraction of Ar in the Ar and C₆H₆ reaction gas. The chemical composition, atomic bond structure, and mechanical properties were investigated for W concentrations ranging from 0 to 8.6 at.%. When the W concentration was <2.8 at.%, the W atoms were dissolved in the amorphous carbon matrix without forming a WC_1-x phase. Amorphous and crystalline WC_1-x nanoparticles appeared when the W concentration was >2.8 and >3.6 at.%, respectively. It was found that the hardness and elastic modulus were not sensitive to the W concentration in this concentration range. On the other hand, the residual compressive stress was strongly dependent on the chemical state of the incorporated W atoms. The change in mechanical properties is discussed in terms of the microstructural changes induced by W incorporation.