Atomistic study of boron-doped silicon

Book · Tue Dec 31 04:00:00 EST 1996

OSTI ID:489007

Fearn, M; Pettifor, D G ^[1]; Jefferson, J H ^[2]

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1. Oxford Univ. (United Kingdom). Dept. of Materials
2. DRA, Great Malvern (United Kingdom)

Atomistic simulations using both tight-binding and density-functional approaches have been performed to investigate boron-related defects in silicon. In agreement with experiment, the boron interstitial is shown to be a negative-U center in the sense that its neutral charge state, with an associated Jahn-Teller distortion off the ideal tetrahedral site, is never the ground state for any value of the chemical potential in the gap. The possible consequences for an electron-assisted migration of the interstitial are discussed. The authors also find the boron substitutional defect to be a next-nearest neighbor of a silicon vacancy in agreement with EPR spectra. A semi-empirical tight-binding model of the boron-silicon system is validated by direct comparison with the accurate density-functional results and is then used to perform molecular dynamics simulations of boron diffusion at high temperatures. The mobility of the interstitial is found to be strongly charge-state dependent. Termination of the boron interstitial migration path by recombination with a silicon vacancy is shown to be a very likely process with a number of configurations having no barrier to capture when the boron is a near-neighbor of the vacancy.

• OSTI ID: 489007
• Report Number(s): CONF-951155--; ISBN 1-55899-311-8
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
BORON
COMPUTERIZED SIMULATION
CRYSTAL DEFECTS
DOPED MATERIALS
INTERSTITIALS
SILICON
THEORETICAL DATA