Copper-Defect and Copper-Impurity Interactions in Silicon

摘要

The key predictions of ab-initio Hartree-Fock (HF) calculations for copper in silicon clusters are reviewed. Preliminary results of ab-initio molecular-dynamics simulations in periodic supercells, based on density-functional (DF) theory with atomic-like basis sets are given. These calculations are performed in periodic supercells containing 64 or 128 host atoms and a varying number of k points. The electronic configuration of interstitial copper predicted by the DF calculations is very similar to the HF one. In a vacancy, copper forms four Cu ― Si covalent bonds. In a divacancy, Cu moves along the <111> direction toward the center of the void and becomes 6-fold coordinated. The interactions between substitutional copper and interstitial hydrogen are obtained from dynamic and static runs. Hydrogen traps at Cu_s without forming Si-H bonds. Instead, copper becomes 5-, 6-, then 7-fold coordinated as one, two, or three H interstitials bind to it.