Lattice site investigation of F in preamorphized Si

The lattice location of F atoms in Si was experimentally studied. Si single crystals were amorphized, implanted with F, and afterwards the amorphous layer was recrystallized. Some of the samples prepared in this way were also annealed at 750 degrees C for 60 min. The F-19(p,alpha gamma)O-16 resonant nuclear reaction at 340.5 keV was employed to measure the probability of a close encounter between protons and F nuclei as a function of the incident angle with respect to six major crystalline directions. The predictions of several ab initio calculations proved to be incompatible with the present experimental findings.