EFFECTS OF BIAS AND INERT-GAS ON PROPERTIES OF DIAMOND-LIKE CARBON DEPOSITED BY DC-PACVD

Diamond-like carbon films were deposited by d.c. plasma-assisted CVD f rom acetylene or cyclohexane at substrate biases of -400 V to -800 V a nd pressures of 100 mTorr and 200 mTorr. The films were characterized for index of refraction, IR absorption, hydrogen content, and wear res istance. The thermal stability in vacuum was also characterized. It wa s found that the properties of the films are dependent on the precurso r and the substrate bias. The properties of the films deposited from a cetylene are only slightly dependent on the substrate bias and diamond -like properties were obtained for the whole range of investigated bia s. In contrast, the properties of the films deposited from cyclohexane are strongly affected by the bias and an absolute bias higher than 50 0 V was required to obtain diamond-like properties at the used dischar ge pressures. Dilution of cyclohexane with an inert gas enhanced the d iamond-like properties of the films deposited at -400 V and a sufficie ntly large dilution ([C6H12]/[Ar]=1/4) produced films having propertie s similar to those of the films deposited at higher