Synthesis of SiC nanofibers by microwave plasma assisted chemical vapour deposition in CH4/H2 gas mixture

We report in this study, the growth of silicon carbide nanofibers on silicon substrates covered by Fe thin film catalyst using microwave plasma assisted chemical vapour deposition. The silicon source is the substrate itself. The growth morphology, microstructure, and defects on SiC nanofibers are characterized by field emission scanning electron microscopy and transmission electron microscopy combined with electron energy-dispersive X-ray spectroscopy. These characterizations revealed that the resultant fibrous nanostructures, with a diameter of 25-65 nm, were assigned to β-SiC. Selected area electron diffraction pattern shows a good crystallinity of the obtained nanofibers, and shows that the SiC nanofibers grow along (111) orientation. The formation of SiC nanofibers can be explained by the diffusion of Fe in the silicon substrate due to the high temperature during the process which is around 900 °C. The combination of the etching of the surface by atomic hydrogen and the interaction with carbon radicals and carbon atoms allows then the growth of SiC nanofibers.