Positron annihilation lifetime experiments were performed on B-doped p-type Czochralski wafers which had been irradiated with 1MeV electrons, at 300K, to fluences of between 1014 and 1017/cm2. In order to examine the behavior of defects which had shorter lifetimes than that of the bulk, isochronal annealing was carried out at 300 to 900K. Measurements were performed at 100K in order to improve the positron trapping rate for defects. It was found that components which had longer lifetimes, than that of the bulk, behaved differently and comprised thermal donors and divacancies. A short-lifetime component was attributed to a complex defect with impure interstitial O atoms, doped B atoms and vacancies. The short-lifetime defects changed into vacancy-type defects and thermal donors within certain annealing-temperature ranges.

Study of Behavior of Electron Irradiation Defects and Impurities in Czochralski Silicon with Annealing by Positron Annihilation. T.Tamano, F.Hori, R.Oshima, T.Hisamatsu: Japanese Journal of Applied Physics - 1, 2001, 40[2A], 452-6