Positron annihilation studies of fluorine-vacancy complexes in phosphorus- and fluorine-implanted germanium

The formation of FnV2 complexes, with n = 5 +/- 1, near the end-of-range damage region in germanium implanted with 30 keV phosphorus and 40 keV fluorine ions, after annealing to 400 degrees C, has been observed using variable-energy positron annihilation spectroscopy in conjunction with secondary ion mass spectrometry. Phosphorus ions were implanted at 6 x 10(13) and 10(15), F at 10(15) cm(-2). Complexes-at lower concentrations-have also been observed at shallower depths in samples implanted with P at 10(15) cm(-2). The complexes break up and their components diffuse away at 450 and 500 degrees C for the higher and lower P dose samples, respectively.