DC vacuum arc deposition system with coiled anode for ta-C films achieving a high deposition rate

Tetrahedral amorphous carbon (ta-C) film, which is one of diamond-like carbon (DLC) film, is widely used for cutting tools and sliding parts because of their high sliding properties, high wear resistance, and high thermal stability. The deposition of ta-C films by vacuum arc discharge requires a reduction in the amount of droplet adhesion, which causes film quality degradation. We have shown that TiN films with a low number of droplets can be formed by using a coiled anode to efficiently transport plasma. In the present study, we applied the same method to ta-C deposition, where the arc current is about 100 A for TiN deposition, but only about 30 A for ta-C deposition. Therefore, we decided to use a coiled anode with about three times as many coil windings as the 3.5 coil windings used for TiN deposition. Comparison of the deposition rate between a 0-winding coiled anode and a 10.5-winding coiled anode showed that the deposition rate increased by a factor of 2 or more with the 10.5-winding coiled anode, and the number of droplets per film thickness was reduced by a factor of 2. The effectiveness of this method was demonstrated. However, it was also found that the ta-C film softens after a long deposition time. This suggests that appropriate cooling is necessary to obtain a hard ta-C film. • DC vacuum arc deposition with coiled anode for ta-C films has been developed. • The deposition system allowed a high deposition rate by coiled anode. • High deposition rate resulted in reduction of adherence of droplets to films. • The prepared films were surely ta-C though the high heat flux is applied.