SiC formation by C60 molecules as a precursor: A synchrotron-radiation photoemission study of the carbonization process

Formation of SiC upon annealing an atomically clean Si(001)-2×1 surface covered with half a monolayer of C60 molecules has been investigated by a synchrotron-radiation photoemission. C60 molecules are chemisorbed at room temperature on the silicon surface via Si–C60 hybridization to form covalent bonds. During annealing of the film at 700°C, Si atoms in the first layer below the surface move upward to bond with C60 molecules, enhancing the formation of SixC60 and resulting in weakened C–C bonds within C60 molecules. Upon further annealing to 750°C, most C60 molecules decompose and formation of the SiC film begins. Total decomposition of C60 molecules occurs at 800°C, and only a SiC film is then found.