Gas Phase Synthesis of Diamond Films

Many attempts to synthesize diamond films have been made recently because of the high potentiality for various applications. The films were produced by a variety of methods, including thermal chemical vapor deposition (CVD) using a hot tungsten filament, plasma CVD and photo-induced CVD. Among these techniques, photo-induced CVD seems promising for the deposition of microelectronic materials at low temperatures. This paper reviews the properties of diamond, its evaluation methods and the progress in the synthesis of diamond by gas-phase deposition. Detailed descriptions are presented on the laser-induced CVD developed by us, in which diamond films are deposited on Si wafers by decomposing a gaseous mixture of CCl4 and H2 with an Ar F excimer laser. The structures of the deposited films were characterized by Raman scattering and reflection electron diffraction analysis. The experimental results obtained from an optical emission spectroscopic study and the reaction mechanism are discussed.