Deposition of Diamond onto an Aluminum Substrate by DC Plasma CVD

Abstract

Diamond films are deposited on an aluminum substrate under a constant high discharge current (I _d=700 mA) and a methane concentration of about 2% by DC plasma CVD, and their structural characteristics resulting from the difference in substrate temperature (T _s: 140–480°C) are investigated. Many diamond particles with an average size of 0.3 µm and having a clear crystal habit are formed at T _s about 480°C. When T _s is decreased, the deposited films tend to contain hydrogenated amorphous components as well as amorphous carbon phases. The films deposited at extremely low T _s, such as 140°C, are composed of submicron grains like pebbles, in which nanocrystalline diamond crystals and amorphous phases having C–C and C–H bonds aggregate to form these submicron grains. It has been found that diamond films with different grain morphology are deposited on the Al substrate.