Defects in Si induced by B and BF2 ion implantation have been investigated by means of coincidence Doppler broadening measurements with a variable energy positron beam. In case of B implantation, the annihilation profiles are almost same for CZ-Si and FZ-Si before annealing. Annealing at 900 degreesC makes the line shape back to that of unimplanted Si for both Si. But, annealing behavior is different between CZ-Si and FZ-Si. This difference may be attributed to presence of oxygen in CZ-Si. For Si implanted with BF2 ions, annihilation profile is different from that of B:Si. The defects are not fully recovered even by 900 degreesC annealing.