Positron annihilation experiments have been performed to identify defects created by annealing of electron irradiated of heavily As-, P-, and Sb-doped Si samples. We show that the vacancy-donor pairs $(V-D_1)$ migrate around 450 K, transforming into $V-D_2$ defects. These defects turn into $V-D_3$ around 700 K provided the doping concentration is high enough. We furthermore show that the $V-{\mathrm{As}}_3$ defects anneal at 1100 K. The formation and annealing of these defects can explain the observed electrical compensation and activation in highly doped Si. We also show that the deconvoluted valence region of the positron-electron momentum distribution can be used to identify atoms neighboring a vacancy and that the chemical effects of individual atoms can be extracted from the momentum distribution.

• Received 13 October 2003

DOI:https://doi.org/10.1103/PhysRevB.69.115205