Abstract
Abstract Comparing the UNCD grown on Ti, Mo and W, the diamond on Mo shows the shortest incubation time. By the XRD, SIMS concentration profile and ESCA surface binding analysis, the substrate with the better chemisorption for carbon and the less carbon solubility will get the shortest diamond growth incubation time. The cross section SEM image of the sample shows the thinner metal interlayer the thicker UNCD grown during the same growth time. By comparing the SEM image results and the carbon solubility of the substrates, the less carbon dissolved into the substrate, the thicker diamond film can be gotten during the same growth time. In order to get thicker diamond films during the same growth time, the substrate with the worse carbon solubility was chosen. For enhancing the chemisorption ability of the substrate, the silicon substrate was pretreated by ultrasonication with the mixed powder (diamond & Ti powder) solution. By SEM image, UNCD film grown on the silicon substrate pretreated with mixed powder solution shows the shortest incubation time and thicker during the same growth time. By SIMS surface analysis, Ti residue on the substrate was identified after mixed powder treated. Because of the high nucleation density, smooth UNCD vertical tip surface can be gotten. The tip size and density were controlled by wet-etching process. Due to the wet-etching control difficulty, the tip size will be different.