Electronically controlled reactions of interstitial iron in silicon

Iron-boron pair dissociation in silicon under strong illumination

“…18,26 Even though there is no data available about the migration energy for Fe − i , it should be larger than that of Fe 0 i , due to its larger radius. 26 The Coulomb repulsion energy is thus not large enough to completely dissociate FeB. For the second mechanism, while, the athermal diffusion of Fe 0 i away from B s − might be caused by REDR, leading to the observed athermal dissociation with an activation energy of (−0.06 ± 0.02) eV, which is very close to the recombination-enhanced dissociation energy of 0.09 eV reported by Kimerling et al 5 As shown in Fig. 4, the activation energy, E s , is (0.21 ± 0.03) eV for the slow dissociation process.…”

“…1,2 It is known that the positively charged interstitial iron atoms (Fe + i ) tend to form iron-boron pairs (FeB) with negatively charged substitutional B atoms (B − s ) at room temperature. [2][3][4] It is well documented also that the pairs can be dissociated by thermal treatment, 5 minority carrier injection, 5 or illumination. 4 Further more the formation and dissociation of FeB can be deliberately cycled.…”

“…[10][11][12] The association energy E a of FeB has been reported to be in the range of 0.65 to 0.69 eV, while the dissociation energy is in the range of 1.17 to 1.22 eV. 13,14 However, the dissociation energy of FeB can be reduced to 0.09 eV with the help of minority carrier injection, due to a recombination-enhanced defect reaction (REDR) 5 based on the following mechanism [15][16][17] : most of the energy released by multiphonon nonradiative (MPNR) capture or recombination of a carrier can be converted into vibrational energy which is initially localized in the vicinity of the defect. This vibrational energy, approximately equal to the carrier transition energy, E ct , [15][16][17] is available to facilitate defect reactions such as diffusion, 18 dissociation of impurity pairs, 19 formation of complexes 17 and motion of dislocations.…”

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

“…For instance, while there are no indications that interstitial Fe, either neutral Fe 0 or positively charged Fe + , should pair with positively charged donors such as As +40 , the formation of pairs between positively charged interstitial Fe + i and negatively charged acceptors, e.g. B − , is a well-known phenomenon [1][2][3]22,23,40 . In the next subsections we discuss each type of observed lattice site that we unambiguously identified, comparing with ab initio calculations 21,40,41 and Mössbauer spectroscopy [42][43][44][45] studies from literature.…”

“…Consequently, providing microscopic information what actually happens to Fe when it encounters Si vacancies in an n + -type environment, as is achieved in this paper, will be crucial to understand the fundamental principles underlying this gettering process. In p + -type Si, on the other hand, the formation of FeB pairs between the acceptor B and interstitial Fe is a well-known phenomenon studied by electrical and optical techniques [1][2][3][22][23][24] , but so far no detailed information on the lattice sites of Fe in such pairs has been available, which is why we have also devoted special attention to this subject. Emission Channeling (EC) is a unique technique which can investigate the lattice sites of low concentrations of impurities in single crystals.…”