ANNEALING KINETICS OF THE DICARBON RADIATION-DAMAGE CENTER IN CRYSTALLINE SILICON

The thermal destruction of dicarbon centers (as monitored by the absorption in the 969-meV G zero-phonon line) in irradiated float-zone silicon is reported for annealing between 150 and 260-degrees-C. We show that four processes occur during the annealing: (a) an intrinsic breakup of the dicarbon center, characterized by an activation energy of almost-equal-to 1900 meV, in which an interstitial carbon atom is emitted; (b) multiple recapture of the interstitial carbon atom at substitutional carbon, leading to a lengthening of the decay time with increasing carbon content; (c) motion of a diffusing species to the dicarbon centers which destroy them at a rate proportional to the radiation dose and with an activation energy of 1250 meV; and (d) a growth process superimposed on the destruction, with an activation energy of 890 meV. Inhomogeneities in the carbon distribution result in nonexponential decays of the dicarbon center and changes in the width of the G absorption line during the annealing.