Theoretical study of vacancy diffusion and vacancy-assisted clustering of antisites in SiC

E. Rauls, Th Frauenheim, A. Gali, P. Deák

Research output: Contribution to journalArticle

70 Citations (Scopus)

Abstract

Using the self-consistent-charge density-functional-based tight-binding (SCC-DFTB) method, we have investigated the migration of vacancies at high temperatures, taking into account the entropy contribution to the Gibbs free energy. We have found that the energy barrier for sublattice migration of V Si is lower than that for VC, so that VSi should anneal out at lower temperatures, which agrees with the experimental observations for as-grown SiC. In irradiated material, vacancies and interstitials are expected to appear in high concentrations. In the early stages of annealing, their recombination can also result in antisites. We show that at annealing temperatures at which vacancies are mobile, their motion can mediate the migration of antisites. The vacancy-assisted diffusion of carbon antisites is much faster than that of silicon antisites and may lead to the formation of carbon antisite clusters. We propose a mechanism for the formation of antisite clusters during the migration of silicon vacancies. The role of these complexes in the formation of very stable defects, observed in irradiated SiC, is discussed, additionally.

Original languageEnglish
Article number155208
Pages (from-to)1552081-1552089
Number of pages9
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume68
Issue number15
Publication statusPublished - Oct 2003

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Vacancies
Silicon
Annealing
Carbon clusters
annealing
carbon
Energy barriers
silicon
Gibbs free energy
Charge density
Temperature
sublattices
interstitials
Entropy
Carbon
entropy
Defects
defects
temperature
energy

ASJC Scopus subject areas

  • Condensed Matter Physics

Cite this

Theoretical study of vacancy diffusion and vacancy-assisted clustering of antisites in SiC. / Rauls, E.; Frauenheim, Th; Gali, A.; Deák, P.

In: Physical Review B - Condensed Matter and Materials Physics, Vol. 68, No. 15, 155208, 10.2003, p. 1552081-1552089.

Research output: Contribution to journalArticle

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