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

The formation of F_nV₂ 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 °C, has been observed using variable-energy positron annihilation spectroscopy in conjunction with secondary ion mass spectrometry. Phosphorus ions were implanted at 6 × 10¹³ and 10¹⁵, F at 10¹⁵ cm⁻². Complexes—at lower concentrations—have also been observed at shallower depths in samples implanted with P at 10¹⁵ cm^−2. The complexes break up and their components diffuse away at 450 and 500 °C for the higher and lower P dose samples, respectively.