Tribological properties of a-C:W film deposited by radio frequency magnetron Co-sputtering method

We deposited the tungsten doped amorphous carbon (a-C :W) film on silicon (Si) substrate by radio frequency (RF) magnetron co-sputtering method. Tungsten (W) was used as the doping metal of a-C film. Carbon and metal components were deposited simultaneously on the Si substrate by co-sputtering method, and the applied RF power on the graphite (C) was 150 W and it on tungsten (W) metal target was from 20 W to 50 W, respectively. In this work, the influence of RF power in W target on the structural, physical, and tribologcal properties of the a-C:W films was experimentally investigated. The hardness increased with increasing RF power in W target and exhibited the maximum hardness value about 18.5 GPa at the condition of RF power in W target, and the adhesion and surface roughness properties improved with increasing RF power in W target. However the friction property is declined with increasing RF power. Consequently, the improvement of physical properties in a-C:W films is associated with the enhancement of energetic ions bombardment and the increase of W contents in amorphous matrix by increasing RF power in W target.