Fluorinated fullerene thin films on Si(111)-(7×7) surface

Thin layers of the C60Fx molecules on the Si(111)-(7×7) surface have been investigated using scanning tunneling microscopy and high-resolution electron energy loss spectroscopy. The latter measurements indicated that the fluorine atoms are detached from C60Fx molecules and adsorb on the Si surface even at room temperature. The C60Fx molecules may release all fluorine atoms, either due to the oscillating motion of a trapped molecule or during their migration (rolling) on the Si surface. The diffusion of fluorine on the Si(111)-(7×7) surface and the initiation of etching in the areas of the higher fluorine concentration were observed at the lower temperature (∼300 °C) than that at isolated fluorine sites.