DLC coatings prepared by hollow cathodes at moderate pressure

DLC coatings were prepared using the rf powered cylindrical and linear hollow cathodes. The deposition process is hybrid, combining both the PE CVD and PVD. A cylindrical graphite nozzle and graphite plates were used as targets. The gas mixture used in the deposition process was argon with acetylene. Compared to e.g. magnetron sputtering, the optimum content of acetylene is lower. The effect of the acetylene content in the gas mixture as well as rf power on the deposition rate and properties of the coatings are evaluated. The geometrical effect is studied, the cylindrical hollow cathode and the linear hollow cathode are compared and the transfer of the optimized process from the cylindrical into the linear hollow cathode is discussed