Carbonization process and SiC formation at C60/Si(111) interface studied by SRPES

Abstract

Carbonization process and SiC formation upon annealing the Si(111) surface covered by C60 molecules with the thickness of 1.3 nm have been investigated by using synchrotron radiation photoelectron spectroscopy (SRPES), X-ray photoemission (XPS) and reflection high energy electron diffraction (RHEED) in NSRL. C60 molecules are chemisorbed on the Si(111) surface at room temperature, via Si-C60 hybridization to form covalent bonds, which can be explained by adsorption model including two adsorption configurations S3 and L. With annealing the sample, the Si-C60 hybridization weakened C-C bonds internally in C60 molecules and enhanced the formation of SixC60, an intermediate species. Further annealing the sample to 650°C will lead to the decomposition of C60 molecules, the released carbon fragment will bond with external silicon atoms to form SiC. While annealing the sample to 850°C, decomposition of all C60 molecules was accomplished, and only a SiC film was left on the surface. © 2008 IOP Publishing Ltd.