Influence of n+ and p+ doping on the lattice sites of implanted Fe in Si

Abstract

We report on the lattice location of implanted 59Fe in n+- and p+-type Si by means of emission channeling. We found clear evidence that the preferred lattice location of Fe changes with the doping of the material. While in n+-type Si Fe prefers displaced bond-centered (BC) sites for annealing temperatures up to 600 °C, changing to ideal substitutional sites above 700 °C, in p+-type Si, Fe prefers to be in displaced tetrahedral interstitial positions after all annealing steps. The dominant lattice sites of Fe in n+-type Si therefore seem to be well characterized for all annealing temperatures by the incorporation of Fe into vacancy-related complexes, either into single vacancies which leads to Fe on ideal substitutional sites, or multiple vacancies, which leads to its incorporation near BC sites. In contrast, in p+-type Si, the major fraction of Fe is clearly interstitial (near-T or ideal T) for all annealing temperatures. The formation and possible lattice sites of Fe in FeB pairs in p+-Si are discussed. ...