Local structure of iron implanted in indium phosphide

Abstract

In an attempt to clarify the origin of the limited electrical activity of Fe implanted in InP we report an X-ray absorption spectroscopy investigation. Fe implantation was performed with a recently developed procedure involving dynamical annealing which is able to increase the electrically active Fe concentration by at least a factor of 100 with respect to previous methods. We have found that Fe is always bonded to P atoms and is never present in the metallic or oxide form. The local structural parameters suggest the formation upon annealing of a disordered Fe P compound, which may be at the origin of the limited electrical activity

Correlation among structural, electrical, and deep-level properties of Fe centers implanted in InP

“…The second important aspect regards the final location of the implanted Fe atoms in the InP lattice: channeling measurements indicate that most of them reside on high symmetry positions along the crystal rows (aligned atoms), with a predominance of Fe atoms in substitutional lattice sites and a minor fraction occupying tetrahedral interstitial positions. The availability of a high number of vacant sites produced by the implantation process evidently favors the substitutional placement of the implanted Fe atoms; this has been confirmed both by HRXRD and XAFS measurements [3,4]. The substitutional, tetrahedral interstitial, and aligned fractions are reported at the implantation temperature (T=220 C) in Fig.…”

“…Finally, at the highest temperature (600 C) iron seems to be completely removed from substitutional sites, at least within the sensitivity of the technique (between 5% and 10%). 4 He + RBS-channeling measurements were performed to investigate the crystal damage evolution as a function of the annealing temperature. The results (not reported here, see Ref.…”