Growth of diamond thin films by dc plasma chemical vapor deposition

Abstract

Diamond thin films have been formed by dc plasma chemical vapor deposition with a high growth rate (∼20 μm/h). The diamond has been grown from methane (CH4) and hydrogen (H2) mixed gases on Si and α-Al2O3 substrates at a pressure of 200 Torr without surface scratching by diamond or c-BN powder. The obtained films have good crystallinity in the sense of electron and x-ray diffraction. Vicker’s hardness of the film is the same as that of natural diamond (∼10 000 kg/mm2). The influence of the dc discharge in a low vacuum (∼200 Torr) on diamond synthesis will be discussed briefly.