Formation of epitaxial β-SiC layers by fullerene-carbonization of silicon(001): a comparison between the use of C60 and C70 molecules

By condensation of C60 and C70 fullerenes the formation of continuous, thick epitaxial β-SiC films on Si(001) and Si(111) surfaces is possible, even at moderate temperatures (700°C–1000°C). The dependence of structure, topography, and composition of the epitaxial silicon carbide layers formed by C60 or C70 carbonization of silicon on the substrate temperature was studied by X-ray diffraction, atomic force microscopy, and Rutherford-backscattering analysis. It could be shown that the quality of the formed epitaxial β-SiC layers is extremely sensitive to the substrate temperature. In the case of C60 and a substrate temperature of 850°C the growth of epitaxial β-SiC layers with only a small number of defects was observed. Lowering the substrate temperature to 775°C resulted in β-SiC layers with a strong texture. Using C70 molecules the process temperature can be lowered further by 75°C. High quality β-SiC layers with a low number of defects can be grown at a substrate temperature of as low as 775°C.