Influence of duct bias on deposition rate of DLC film in T-shape filtered arc deposition

Diamond-like carbon (DLC) films were deposited by a T-shape filtered arc deposition (T-FAD) apparatus, applying bias voltage to the plasma transportation duct which filters the macrodroplet emitted from the cathode, in order to obtain a higher deposition rate. Ion current, deposition rate, discharge voltage, duct current, and anode current were measured as a function of duct bias. The anode current decreased and the duct current increased when a positive bias was applied to the duct. This fact indicates that the T-shape duct acted as another anode of the vacuum arc discharge. It was found that the maximum deposition rate as well as the ion current was obtained at about 15 V of duct bias. Improvement in plasma transportation to the process chamber through the duct was considered from the viewpoint of the characteristics of duct current against bias voltage. The value of the optimum duct bias was the same as the intersection point of the characteristics of duct current against bias voltage.