Evidence for identification of the divacancy-oxygen center in Si

A deep level transient spectroscopy (DLTS) study of electronic defect levels in 15 MeV electron irradiated n-type float-zone Si samples with different oxygen contents has been performed. Heat treatment at 250 °C results in a shift of both the singly negative and doubly negative divacancy $\left({\mathrm{V}}_2\right)$ related DLTS peaks. This is due to annealing of ${\mathrm{V}}_2$ and the formation of a new double acceptor center. The formation of the new center has a close one-to-one correlation with the annealing of ${\mathrm{V}}_2.$ The annealing rate of ${\mathrm{V}}_2$ and the formation rate of the new center are close to proportional with the oxygen content in the samples. The new center is identified as a divacancy-oxygen complex.