First principles study of oxygen defects in silicon

Abstract

Large scale electronic structure calculations are used to study atomic and electronic structures of oxygen complexes O n (1⩽ n⩽14) and their migration and isomerization in crystalline silicon. Total energies, atomic geometries, charge states, and ionization levels are investigated for the various types of defects. The thermodynamic and the kinetic behaviours of defects are discussed on the basis of the first principles results. The chain-like structures are energetically more favorable than branched ones. The migration energies of the chain-like structures are 0.3 ∼ 2.3 eV and those of branched ones are 2.3 ∼ 2.5 eV. The activation barriers for the isomerizations between different structures are about 2.3 ∼ 2.5 eV.