Effects of Bias Voltage on Structure and Property of Si-DLC Films Fabricated by Self-source Cage Type Hollow Cathode Discharge Process

To solve the problems of difficult operation of large workpieces in the meshed cage and the influence of large workpieces on the discharge when using the meshed cage hollow cathode discharge to prepare DLC film on the surface of large workpieces, a self-source cage type hollow cathode discharge method was developed. Si-DLC films were deposited on Si (100) wafers at different bias voltage (-300 similar to 0 V) using a self-source cage type hollow cathode discharge process. The influence of bias on the structure and properties of Si-DLC films was investigated. The results show that the deposition rate of Si-DLC films reach 7.90 mu m/h. The high-energy ion bombardment caused by bias significantly densifies the films, and reduces the surface roughness and H contents. The sp(3)/sp(2) value in the Si-DLC film firstly increases and then decreases with the increase of bias, and the nano-hardness and elastic modulus of the film show the same rule. The Si-DLC films deposited with a bias of -200 V have the highest sp(3)/sp(2) value (0.69), H/E and H-3/E-2, and show excellent anti-friction performance with a friction coefficient as low as 0.024 and a wear rate of 1*10(-6) mm(3)/Nm. It is indicated that the self-source cage type hollow cathode discharge is an effective process for the preparation of large-area DLC film. The -200 V bias is the optimal parameter.