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Title: Phosphorus doping of Si nanocrystals embedded in silicon oxynitride determined by atom probe tomography

Silicon nanocrystals (SiNCs) embedded in a silicon oxide matrix were studied by 3D atom probe tomography (APT). The distribution of the SiNC diameter was found to have a mean value of 3.7 ± 0.8 nm. The elemental composition of these particles was determined by employing two different approaches: (i) The proximity histogram method and (ii) a cluster identification algorithm based on maximum-atom separations. Both approaches give very similar values in terms of the amount of P, O, and Si within the SiNCs: the mean atomic concentrations are c{sub P} = 0.77% ± 0.4%, c{sub O} = 12.3% ± 2.1%, and c{sub Si} = 85.3% ± 2.1%. A detailed cluster analysis implies that, on average, a 4.5-nm SiNC would contain around 30 P atoms, whereas a 2.0-nm SiNC would contain only around 3 P atoms. Radial concentration profiles obtained for these SiNCs indicate that the P content is inhomogeneous and possibly enhanced at the boundary as compared to the interior of the NCs. About 20% of the P atoms are found to be incorporated into the SiNCs, whereas roughly 30% are trapped within the interfacial layer (with a thickness of ∼ 0.8 nm); the remainder resides in the surrounding matrix. Cluster-size dependent P concentrations support the view of self-purification in the Si nanostructures.
Authors:
;  [1] ;  [2] ; ; ;  [3] ; ;  [1]
  1. Institut für Oberflächen- und Schichtanalytik (IFOS) and Forschungszentrum OPTIMAS, Trippstadter Str. 120, 67663 Kaiserslautern (Germany)
  2. (Germany)
  3. IMTEK, Albert-Ludwigs-Universität Freiburg, 79110 Freiburg (Germany)
Publication Date:
OSTI Identifier:
22275704
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 115; Journal Issue: 3; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ATOMS; CONCENTRATION RATIO; INTERFACES; LAYERS; MATRIX MATERIALS; NANOSTRUCTURES; PHOSPHORUS; SILICON; SILICON NITRIDES; SILICON OXIDES; TOMOGRAPHY