It was recalled that the electrical properties of Si materials containing dislocations were strongly affected by deep levels at, or close to, the dislocation core. Such deep levels were frequently thought to be due to metal impurities that were chemically bound to the dislocation core, segregated in the long-range strain field or precipitated at the dislocation. Recent experimental studies of the interaction of metal impurities with dislocations in Si were summarized here. Transmission electron microscopy and deep level transient spectroscopy were the main techniques used to study precipitation at dislocations and the binding or segregation of metal impurity atoms, respectively. Attention was drawn to the precipitation of fast-diffusing 3d transition metals where dislocations not only served as nucleation sites but also established fast growth kinetics. In addition, Au impurities in the strain field of dislocations gave rise to an acceptor level with the capture kinetics of extended localized defects while the emission characteristics were hardly distinguished from those of the acceptor level of Au atoms in the undisturbed bulk. The results were considered in terms of possible responses of the deep impurity level and the Si bands to the dislocation strain field.

Structural and Electrical Properties of Metal Impurities at Dislocations in Silicon. M.Seibt, V.Kveder, W.Schröter, O.Voss: Physica Status Solidi A, 2005, 202[5], 911-20