High-Fluence C-Implantation into 3C-SiC: Synthesis of Buried Diamond-Nanocrystals

Their outstanding properties, such as wide band gap, high thermal conductivity and saturated electron drift velocity, make silicon carbide and diamond useful semiconductors for applications under harsh conditions. A combination of both materials on a microscopic scale may be a promising way to novel devices.
Ion Beam Synthesis (IBS) is an excellent method for creating precipitates inside any matrix without thermodynamic constraints. We previously demonstrated the synthesis of nanocrystalline 3C-SiC inside diamond by high-fluence Si implantation. In this work we investigate phase formation in carbon-implanted 3C-SiC substrates. Implantations were performed with different fluences ranging form 3x1017 cm-2 to 3x1018 cm-2. Additionally, the influence of implantation temperature and dose rate was studied using X-ray diffraction (XRD), Raman spectrometry and high-resolution cross-sectional transmission electron microscopy (HRTEM).
Low implantation temperatures and high dose rates favor the formation of graphite precipitates in a textured form, while in all other cases epitaxial diamond nanocrystals grow. Hence, a critical temperature for diamond formation exists, which depends on dose rate. Increasing the fluence leads to bigger nanocrystals. Diamond platelets of up to 20 nm length were found.