Adhesive Microcrystalline Diamond Coating on Surface Modified Non-Carbide Forming Substrate Using Hot Filament CVD

Diamond thin films on non-carbide-forming metals such as copper have always had a large research potential because of the technological importance of copper as a substrate as well as its extensive use in microelectronic devices. However, the inability of copper to form carbides as well as the large mismatch in thermal expansion coefficients result in the generation of very high stresses in the coating that lead to delamination, film cracking, or other deleterious effects. We report on a method to increase the adherence of diamond coatings on copper substrates based on a surface modification process. A copper substrate is sandblasted in order to increase the surface roughness and surface area considerably. This process is expected to enhance the mechanical interlocking between the substrate and diamond film and has increased the seed density and surface energy as well. Microcrystalline diamond thin films were deposited on sandblasted copper substrates using hot filament chemical vapor deposition technique. Adhesion property of diamond coatings was evaluated by thermal quench technique combined with Raman spectroscopy.