Vacancy aggregates in silicon

J. L. Hastings, S. K. Estreicher, P. A. Fedders

Research output: Contribution to journalArticlepeer-review

5 Scopus citations


We have calculated the lowest-energy configurations, stability, and electronic structures of vacancy aggregates (Vn) containing up to n=7 vacancies. The calculations were done using first-principles tight-binding molecular-dynamics simulations (in periodic supercells) and at (and near) the ab-initio Hartree-Fock level (in molecular clusters). The results show that the reaction Vn-1+ V1 → Vn is exothermic at least up to n=7. The most stable aggregate, by far, is the ring-hexavacancy (V6) which has remarkable properties. In contrast to the other Vn's, it is not vacancy-like: It has no deep level in the gap and its dipole moment is extremely small. It is sufficiently stable to survive high-temperature annealing. V6 is a small trigonal void which is likely to be a gettering center and is a plausible nucleus for a range of extended defects.

Original languageEnglish (US)
Pages (from-to)509-514
Number of pages6
JournalMaterials Science Forum
Issue numberPART 1
StatePublished - 1997


  • Molecular-dynamics
  • Ring-hexavacancy
  • Silicon
  • Vacancies

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering


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