Enhanced diamond nucleation density utilising seeding

This paper reports on a new technique for surface pre-treatment of silicon and other substrate materials to enhance diamond nucleation before diamond deposition. Polycrystalline diamond particles (ballas or cauliflower diamond particles) are grown in a CVD environment under hydrocarbon concentrations of 8-15%. After 15 min of growth, the substrate is removed from the process equipment and mechanically treated so that the ballas diamonds are disintegrated into their constituent nanometer-sized diamond crystals and are evenly spread over the surface of the substrate. The small diamond crystals then act as nuclei for the formation of a diamond film in the subsequent diamond growth process. Nucleation densities on virgin silicon wafers of 5 × 10¹⁰cm^-2 have been achieved with this method, and it is believed that even higher nucleation densities can be achieved by further optimisation of the process.