The effect of the substrate bias voltage and the deposition pressure on the properties of diamond-like carbon produced by inductively coupled plasma assisted chemical vapor deposition

Diamond-like carbon (DLC) films were deposited by inductively coupled plasma (ICP) assisted CVD using a gas mixture of Ar and C2H2. The film showed one (37 GPa) of the highest hardness values for a DLC film produced by CVD at the optimum process condition. The film hardness increased rapidly with decreasing hydrogen content in the film. By applying ICP, the hydrogen content could be reduced to approximately 20%, which is the lowest value among those reported in the literature. It is believed that the film hardness is affected by the hydrogen content in the film up to a certain (∼25%) hydrogen concentration.