Atomic structure and electronic states of nickel and copper silicides in silicon

This paper summarizes current understanding of structural and electronic pr operties of nickel and copper silicide precipitates in silicon. From high-r esolution electron microscopy studies it has been concluded that metastable structures form during early stages of precipitation which transform into energetically more favourable configurations during additional annealing or slow cooling. These structural transformations are related to changes of t he electronic structure of the precipitates as revealed by deep level trans ient spectroscopy (DLTS) and electron beam induced current (EBIC). Deep ban dlike states at initially formed NiSi2-and Cu,Si-platelets detected by DLTS have been attributed to a bounding dislocation and precipitate/matrix inte rfaces, respectively. Large NiSi2-precipitates act as internal Schottky bar riers and may control the minority carrier lifetime of silicon samples. Rec ent advances in modeling EBIC contrasts provide insight how metal impuritie s affect the electrical behaviour of dislocations at different degrees of d ecoration. (C) 2000 Elsevier Science S.A. All rights reserved.