Two deep level transient spectroscopy electron emission signatures, previously labelled E4 and E5, were shown to be bistable with respect to minority carrier injection at room temperature. These resulted from 2 charge state transitions of the same defect. Deep level transient spectroscopy measurements were performed as a function of annealing between 350 and 680K, using minority carrier injection after each annealing stage to make E4 and E5 visible. It was shown that the E4–E5 pair was associated with defect clusters which predominated after neutron or ion damage with annealing characteristics that closely parallelled those of Si divacancies found in damage clusters. Upon annealing at above 500K, the E4–E5 pair ceased to be bistable and existed after annealing in thermal equilibrium. It was shown that the stable E4 peak appeared to be the same emission signature previously labelled as the L center. The transformation of the E4–E5 bistable pair into the stable L center and a stable E5 companion level occurred at the same temperature, where it was suggested that the divacancy became mobile. The similarity of the annealing of the E4–E5 pair to that of the divacancy, the dependence of the density of these defects upon the degree of clustering, and the insensitivity to common impurities combined to suggest that the E4–E5 pair was associated with primary defects located in the defect cluster and closely related to the familiar divacancy.

A Bistable Divacancylike Defect in Silicon Damage Cascades. R.M.Fleming, C.H.Seager, D.V.Lang, E.Bielejec, J.M.Campbell: Journal of Applied Physics, 2008, 104[8], 083702