Deep-level transient spectroscopy studies of electronic defect levels in 7MeV proton-irradiated n-type float-zone Si with a dopant content of 3 x 1012 to 5 x 1012/cm3 and O content of some 1016 to 1017/cm3 were performed. The thermal stability of the irradiation-induced defects was investigated at up to 400C. It was found that annealing of the divacancy-related levels, the singly negative, V20/–, and the doubly negative, V2-/=, charge states at 220 to 300C results in the formation of a new center with singly negative, X0/-, and doubly negative, X-/=, charge states. The new center annealed out at 325 to 350C during isochronal treatment for 0.25h. The capture kinetics studies reveal that the electron capture cross-section of X0/- was larger than that of V20/- while the capture cross-section of X-/= was close to that of V2-/=. The transformation of V20/- and V2-/= into X0/- and X-/= was very efficient with only a small loss in the peak amplitudes, and the position of the energy levels were close to those of V2. Hence, it was tempting to suggest that the atomic configuration of the X center was closely related to that of V2, and a possible identification of X may be the divacancy-O center (V2O).

Formation of a Double Acceptor Center during Divacancy Annealing in Low-Doped High-Purity Oxygenated Si. E.V.Monakhov, B.S.Avset, A.Hallén, B.G.Svensson: Physical Review B, 2002, 65[23], 233207 (4pp)