Direct observation of the lattice sites of implanted manganese in silicon

Autor: Ulrich Wahl, Daniel José Cardoso da Silva, Lino Miguel da Costa Pereira, Stefan Decoster, J. G. Correia, João P. Araújo, L. M. Amorim, Manuel Ribeiro da Silva
Rok vydání: 2016
Předmět:
Zdroj: Applied Physics A. 122
ISSN: 1432-0630
0947-8396
Popis: Mn-doped Si has attracted significant interest in the context of dilute magnetic semiconductors. We investigated the lattice location of implanted Mn in silicon of different doping types (n, n+ and p+) in the highly dilute regime. Three different lattice sites were identified by means of emission channeling experiments: ideal substitutional sites; sites displaced from bond-centered towards substitutional sites and sites displaced from anti-bonding towards tetrahedral interstitial sites. For all doping types investigated, the substitutional fraction remained below ∼ 30%. We discuss the origin of the observed lattice sites as well as the implications of such structures on the understanding of Mn-doped Si systems. We have studied the influence of electronic doping on the preferred lattice sites of implanted 61Co, and the related stabilities against thermal annealing, in silicon. Using the beta- emission channeling technique we have identified Co on ideal substitutional (ideal S) sites, sites displaced from bond-centered towards substitutional (near-BC) sites and sites displaced from tetrahedral interstitial towards anti-bonding (near-T) sites. We show clearly that the fractions of Co on these lattice sites change with doping. While near-BC sites prevail in n+-type Si, near-T sites are preferred in p+-type Si. Less than ∼35% of Co occupies ideal S sites in both types of heavily doped silicon, showing that the majority of implanted Co forms complex defect structures. Implantation-induced defects seem to getter more efficiently Co in lightly doped n-type than in heavily doped n+- or p+-type silicon. The formation of CoB pairs in p+-type silicon and its possible influence on the lattice sites is discussed.
Databáze: OpenAIRE