The effect of O and C upon the generation and annihilation of radiation defects was studied by means of deep-level transient spectroscopic and photoluminescence techniques. Samples of n+p diodes with interstitial O contents of between 1016 and 1018/cm3, and C contents of less than 1016/cm3, were irradiated with 2MeV electrons to fluences ranging from 5 x 1014 to 1016/cm2. The deep-level transient spectra revealed the presence of 2 hole traps that were characterized by activation energies of 0.19 and 0.36eV. A comparison with photoluminescence data confirmed that the 0.36eV level was associated with a CiOi and/or CiCs complex. Isothermal annealing at 200C resulted in a gradual conversion of the Ev+0.19eV level to a defect level at Ev+0.24eV. On the basis of the O concentration-dependence of the transformation, it was suggested that the di-vacancy diffused and was trapped by interstitial O to form a V2O complex.

M.A.Trauwärt, J.Vanhellemont, H.E.Maes, A.M.Van Bavel, G.Langouche, A.Stesmans, P.Clauws: Materials Science and Engineering B, 1996, 36[1-3], 196-9