Nanocrystalline diamond matrix deposited on copper substrate by radical species restricted diffusion

Nanocrystalline diamond matrix (or patterned nanocrystalline diamond) have been grown by hot filament chemical vapor deposition (HFCVD) on copper substrates, which were masked by a copper template filled with through-holes. The influence of the mixing ratio for CH4/H2 source gases, total gas pressure and the aspect ratio (the ratio of hole depth to its diameter) on the morphology, grain size and quality of diamond films were investigated. Continuous diamond films were obtained under 2.0 kpa. When increasing the aspect ratio from 0.67 to 2.0, a gradual reduction of diamond grain size from micrometer to nanometers scale was observed. The formation of nanocrystalline diamond (NCD) matrix can be attributed to the restricted diffusion of radical species and the diamond nucleation kinetics on copper substrates. By through-holes of templates on copper substrates to restrict the diffusion and transport of radical species, NCD matrix was successfully deposited on copper substrates.