Deposition of Ti-DLC films by arc-glow hybrid plasma CVD

Summary form only given, as follows. This study presents fabrication of nano-structured Ti-DLC films using arc-glow hybrid plasma. A deposition apparatus consists of a DC plasma torch, a substrate holder and a vacuum chamber. An orifice of 10 mm diameter mounted at the exit of the torch can generate pressure difference between the torch and the chamber. The chamber is evacuated by a dry pump of 5,000 L/min. The orifice and the large-scale vacuum pump enable to keep the pressure in chamber at 20 - 100 Pa, even if the pressure in the torch is 1 atm. The torch employs hollow cathode made of Ti, the Ti is evaporated by the arc discharge, and then sprayed onto the substrate with a plasma jet. The pressure in chamber is low enough to generate a glow discharge. The 13.56 MHz RF power supply is connected to the substrate holder to generate a glow discharge plasma as well as to add a negative bias on the substrate. Deposition of Ti-DLC films were performed using C/sub 2/H/sub 2/ and CH/sub 4/ as the reactant gases. SEM observation and EDAX analysis results suggest that the film includes not only nano-size (i.e. 1-50 nm) Ti particles but also large droplets in carbon matrix. The carbon matrix was assured as DLC according to Raman spectroscopy. The swirl flow generator was adopted to reduce the droplets, it was found that most of droplets were eliminated when C/sub 2/H/sub 2/ was supplied into the plasma torch together with Ar in the swirl flow. The hardness of the deposited film increased from 13 to 30 GPa with decreasing the Ti content in the film from 0 to 30 vol.%. The thickness of the film was approximately 5 um in 1 h deposition and the friction coefficient was 0.3 against stainless steel ball. The residual stress seems to be decreased by the dispersed Ti nano-particle.