Daniel José da Silva

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

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 600u2009°C, changing to ideal substitutional sites above 700u2009°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. ...

Origin of the lattice sites occupied by implanted Co in Si

We have investigated the lattice location of implanted in silicon. By means of emission channeling, three different lattice sites have been identified: ideal substitutional sites, displaced bond-centered sites and displaced tetrahedral interstitial sites. To assess the origin of the observed lattice sites we have compared our results to emission channeling studies on and and to Mossbauer spectroscopy experiments on , present in literature. The possible interpretation of several Mossbauer lines is discussed in the light of our new results on the lattice location. The conclusions are relevant for the microscopic understanding of some gettering techniques.

Identification of the interstitial Mn site in ferromagnetic (Ga,Mn)As

We determined the lattice location of Mn in ferromagnetic (Ga,Mn)As using the electron emission channeling technique. We show that interstitial Mn occupies the tetrahedral site with As nearest neighbors (TAs) both before and after thermal annealing at 200u2009°C, whereas the occupancy of the tetrahedral site with Ga nearest neighbors (TGa) is negligible. TAs is therefore the energetically favorable site for interstitial Mn in isolated form as well as when forming complexes with substitutional Mn. These results shed new light on the long standing controversy regarding TAs versus TGa occupancy of interstitial Mn in (Ga,Mn)As.