FLUORINE-RELATED DEFECTS IN BF2-IMPLANTED SI PROBED BY MONOENERGETIC POSITRON BEAMS()

Fluorine-related defects in 30-keV BF2+-implanted Si were probed using monoenergetic position beams. From measurements of Doppler broadening profiles of the annihilation radiation as a function of incident posi tron energy and those of lifetime spectra of positrons, depth profiles of defects and the species of the defects were determined. For an as- implanted specimen, the major species of the defects below the amorpho us region was identified to be divacancies. Upon rapid thermal anneali ng above 700 degrees C, solid phase epitaxial growth of the amorphous region started, but no shift of the depth profile of defects detected by the positron annihilation technique was observed. During the regrow th of the amorphous region, vacancy-fluorine complexes were introduced . The complexes between vacancy clusters and fluorine atoms were obser ved even after 1100 degrees C annealing.