Formation and incorporation of $SiF4$ molecules in F-implanted preamorphized Si

The local structure of fluorine incorporated in crystalline silicon following solid phase epitaxial regrowth was investigated by means of x-ray absorption spectroscopy at the F $K$-edge. We clearly demonstrate that most F is found in $SiF4$ molecules in the crystalline matrix. A kinetic pathway, which explains our observation and which is also able to rationalize previous results in a common and coherent framework, is proposed.