T. Takahagi et al., CHEMICAL-STRUCTURE AND REACTIVITY OF A SILICON SINGLE-CRYSTAL SURFACEFLUORINATED BY XENON FLUORIDE, Journal of applied physics, 76(5), 1994, pp. 3140-3143
A reconstructed Si single crystal surface was fluorinated using xenon
fluoride. All dangling bonds on the 2 X 1 reconstructed surface of Si(
100) were terminated by fluorine atoms, and Si-F bonds were generated.
However, dimer bonds remained after the treatment. This is different
from the situation where dimer bonds are easily terminated by hydrogen
atoms in a hydrogenation treatment. A bulky Si-F group is considered
to sterically hinder fluorine termination of a dimer bond. Also, only
an adatom bond seems to be terminated by a fluorine atom in the fluori
nation treatment of a Si(Ill) 7 X 7 reconstructed surface. When the fl
uorinated Si(100) surface was exposed to the atmosphere, dimer bonds w
ere observed to be oxidized immediately. Also following the reaction,
the backbond of the Si-F group is oxidized and the S-F bond itself was
hydrolyzed. The fluorinated surface, which is chemically active, diff
ers from the hydrogen-passivated surface.