Ab-initio theoretical methods are increasingly being used to study the properties of defects in covalent materials such as silicon. Static properties include potential energy surfaces, binding energies, and electronic structures. The dynamics involve diffusion, vibrational properties, and defect reactions. This paper describes a powerful combination of methods used to study the interactions involving vacancies, self-interstitials, and impurities in Si. The methods are Hartree-Fock in molecular clusters and density-functional based molecular-dynamics simulations in periodic supercells. Three examples of applications are discussed: 1. the dissociation of interstitial H2 molecules by vacancies and self-interstitials, and the formation of H*2, 2. the aggregation of vacancies leading to the formation of the ring-hexavacancy (V6), and 3. the trapping of interstitial copper at V6 and the origin of the electrical activity of copper precipitates.
|Number of pages||20|
|Journal||Physica Status Solidi (B) Basic Research|
|State||Published - Jan 2000|