Lattice location study of implanted In in Ge

We report on emission channeling experiments to determine the lattice location and the thermal stability of implanted 111In atoms in Ge. The majority of the In atoms was found on the substitutional site, which is a thermally stable site at least up to 500 deg. C. We also found strong indication that directly after implantation, a fraction of the implanted 111In atoms occupies the bond-centered (BC) site. This fraction disappears after annealing at 300 deg. C. From comparison with ab initio calculations, electrical studies, and perturbed angular correlation experiments, the In atoms on the BC site can be related to In-vacancy and In-self-interstitial defect complexes. The activation energy for dissociation of this BC related defect was found to be below 1.6 eV.