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

Abstract

We report on the lattice location of implanted 59 Fe 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. We also address the relevance of our findings for the understanding of the gettering effects caused by radiation damage or P-diffusion, the latter involving n + -doped regions.

Direct observation of the lattice sites of implanted manganese in silicon

“…In that respect, we should note that all samples were implanted as received from the manufacturer without any treatment to remove the native oxide. In fact, when compared to previous emission channeling investigations on Fe, Ni and Co, where marked differences were detected between different doping types, 24,29,30 here a less pronounced influence on the lattice sites is observed, which may have its origin in the depth profile of Mn implanted at 30 keV being located closer to the surface and possibly partially in a region of Fermi level pinning. Last but not least, aggregation of Mn may also occur.…”

“…This phenomenon is similar to the so-called counterdoping, well known for Fe. 29 Another explanation for the observed more thermally stable substitutional Mn comes from the possible formation of Mn − As + pairs. In fact, Zhu et al proposed in 2008 a model where the substitutional incorporation of Mn in Si is enhanced by doping with n-type impurities, such as As.…”

“…24,27,29 Several origins have been proposed, however all involving the trapping of the TM into multivacancy defects. One suggested mechanism was the trapping of the TMs into the center of double vacancies.…”

Lattice location and thermal stability of implanted nickel in silicon studied by on-line emission channeling

“…19, it appears that only vacancies, self interstitials and the formation of 65 Ni clusters might be responsible for the confinement of 65 Ni at the channeling region. As was suggested by a recent theoretical study 6 vacancies are very stable traps for Ni, while interactions with Si interstitials, C and O impurities or other Ni atoms seem to play only a minor role.…”

“…On their way out of the crystal, β − particles experience channeling effects along low-index crystallographic directions, depending on the lattice site occupied by the probe atom. EC has been used to study the lattice sites of long-lived TM isotopes in Si, such as 67 Cu (t 1/2 =2 d), 14-17 59 Fe (45 d) [17][18][19] and 111 Ag (7.45 d), 20 by means of off-line experiments. Studies of other TMs, in particular Ni, Co and Mn, were not feasible since the only suitable isotopes were too short-lived in order to be used off-line.…”