Initial growth of nanocrystalline diamond/β-SiC composite films: A competitive deposition process - art. no. 073109

Although nanocrystalline diamond/beta-SiC composite gradient interlayers have been successfully deposited in dealing with the problem of diamond thin-film adhesion to metallic substrates, initial growth process of the two components has not been described, so far. In this letter, we propose that the deposition of composite interlayer is possible because of a selective growth process of diamond and beta-SiC phases. There is a competition between the diamond and the beta-SiC crystallites to occupy the spaces available on the substrate. The space competition is during the initial nucleation period of the process and also during film growth, leading to the formation of the nanocrystalline composite. The secondary nucleation of beta-SiC on the existing diamond surfaces depends on the flux of incoming beta-SiC forming gas species. This provides us with a possibility to control phase structure and composition of the composite film by adjusting the tetramethyl silane flow rate.