Dynamics of self-interstitial cluster formation in silicon

Abstract

Energy barriers and rebonding effects associated with the formation of silicon di- and tri-interstitial clusters are examined using the pseudopotential plane wave technique. For both defects we report two distinctive metastable configurations. We elucidate in detail the structural differences of these configurations and the method of their formation from single interstitials. The electronic bond topology using the quantum theory of atoms in molecules [R. F. W. Bader, Atoms in Molecules. A Quantum Theory, Vol. 22 of International Series of Monographs on Chemistry (Oxford University Press, Oxford, 1990)] reveals that in general stronger bonds correspond to shorter interatomic distances. However, exceptions occur when the distances exceed the perfect bond distance (>2.5 \AA{}). Furthermore, no barrier exists during the capture of the interstitial during the formation process. This indicates a high probability of capture of a self-interstitial, once it wanders within a radius of 4.1 \AA{} of a defect cluster.