Preparation and characteristics of CVD diamond films

Diamond films were prepared on Si, Mo, W and WC by use of hot filament thermal chemical vapor deposition of tungsten. The nucleation study of diamond on the Si substrate indicated that diamond nucleation density is mainly dependent on the surface states, surface materials and the temperature of substrate. Selective deposition of diamond films on a Si surface was achieved by patterned masking the substrate surface with SiO2 layers. A phase of SiC was detected in the interface of diamond and silicon by X-ray Photoelectron Spectroscopy. By atomic boron doping with hexagonal BN or elemental boron, p-type semiconducting diamond films on Si substrate were prepared. Up to 1018 cm-3 atomic concentration of boron and 2.0 Ω cm specific resistance, high crystal quality of diamond still remained. Cathodoluminescence (CL) and Photo-luminescence (PL) of doped and undoped diamond films were investigated. As a result, a visible blue-green emission was found, which is of very great significance for the applications of diamond films in perspective as a new type of luminescence material. As an application of diamond films, the heat sinks for semiconductor laser diode arrays were fabricated.