Diamond formation in cubic silicon carbide

High-dose carbon implantation (3×1017 and 1×1018 ions/cm2) into cubic SiC on Si was carried out at elevated temperatures (600 to 1200 °C) and different dose rates (1×1013 to 1.5×1014 cm−2 s−1). Transmission electron microscopy revealed the formation of either graphite or diamond precipitates, depending on the implantation parameters. In all cases, the diamond grains were epitaxial to the SiC lattice, while the graphite was textured. The minimum temperature for diamond formation was 900 °C, while graphite formed at 600 °C. The synthesized phase depends as well on the dose rate; graphite was formed at 900 °C with a high dose rate. Obviously, a critical temperature for diamond formation exists and increases with increasing dose rate. This behavior is explained by the competition between the accumulation and dynamic annealing of radiation defects in the SiC lattice, which acts as a template for diamond nucleation. Diamond grains with diameters as large as 10 nm have been observed after implantation at 1200 °C.