Friction and Wear of Diamond-Like Carbon Films Produced by Plasma-Assisted CVD Technique

Diamond-like carbon (DLC) films were deposited on silicon substreates by using an RF plasmaassisted CVD apparatus; the effects of deposition conditions such as CH₄gas pressure and substrate bias voltage on DLC film friction and wear were examined in both friction and scratch tests. In friction tests critical loads at which the friction coefficient increases abruptly depend on substrate bias voltages: critical loads deposited at a bias voltage of -100 V exceed those deposited at other bias voltages. Critical loads are correlated with DLC film hydrogen content. Critical DLC film loads in scratch tests depended considerably less than in friction tests. The friction coefficient of DLC films depends on neither substrate bias voltage nor CH₄ gas pressure.