We report deep-level transient spectroscopy studies on the divacancy formation in electron-bombarded silicon at 80 K. Samples irradiated to a dose $D_1$=3.5×${10}^{16}$ $e^{\mathrm{-}}$/${\mathrm{cm}}^2$ and using a beam current $i_1$=0.33 μA/${\mathrm{cm}}^2$ give rise to an unstable peak seen to anneal out rapidly below 150 K. The center responsible for this peak seems to act as an intermediate step in the formation of at least a fraction of the neutral divacancies. Under conditions of irradiation with dose $D_2$=1.7×${10}^{16}$ $e^{\mathrm{-}}$/${\mathrm{cm}}^2$ and beam current $i_2$=0.20 μA/${\mathrm{cm}}^2$ neither the intermediate defect nor the neutral divacancy signal appears in the spectrum. Instead, a divacancy-related $E_V$+0.13 eV level emerged. An interpretation of the data is attempted in terms of a model postulating charge-state-dependent metastable structures.

• Received 22 December 1986

DOI:https://doi.org/10.1103/PhysRevB.35.7511