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Title: Boron diffusion in nanocrystalline 3C-SiC

The diffusion of boron in nanocrystalline silicon carbide (nc-SiC) films with a grain size of 4–7 nm is studied using a poly-Si boron source. Diffusion is found to be much faster than in monocrystalline SiC as it takes place within the grain boundary (GB) network. Drive-in temperatures of 900–1000°C are suitable for creating shallow boron profiles up to 100 nm deep, while 1100°C is sufficient to flood the 200 nm thick films with boron. From the resulting plateau at 1100 °C a boron segregation coefficient of 28 between nc-SiC and the Si substrate, as well as a GB boron solubility limit of 0.2 nm{sup −2} is determined. GB diffusion in the bulk of the films is Fickian and thermally activated with D{sub GB}(T)=(3.1−5.6)×10{sup 7}exp(−5.03±0.16  eV/k{sub B}T) cm{sup 2}s{sup −1}. The activation energy is interpreted in terms of a trapping mechanism at dangling bonds. Higher boron concentrations are present at the nc-SiC surface and are attributed to immobilized boron.
Authors:
 [1] ;  [2] ; ; ; ;  [1] ; ;  [3] ;  [4] ;  [5]
  1. Fraunhofer ISE, Heidenhofstr. 2, 79110 Freiburg (Germany)
  2. (United Kingdom)
  3. CNR-IMM, Via Piero Gobetti 101, 40129 Bologna (Italy)
  4. CNR-IMM MATIS, Via S. Sofia 64, 95123 Catania (Italy)
  5. Department of Materials, University of Oxford, Parks Rd, Oxford OX1 3PH (United Kingdom)
Publication Date:
OSTI Identifier:
22300117
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 104; Journal Issue: 21; 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; ACTIVATION ENERGY; BORON; CRYSTALS; DIFFUSION; EV RANGE; FILMS; GRAIN BOUNDARIES; GRAIN SIZE; NANOSTRUCTURES; SEGREGATION; SILICON CARBIDES; SOLUBILITY; SUBSTRATES; SURFACES; TEMPERATURE RANGE 1000-4000 K; TRAPPING