Study on behavior of electron irradiation defects and impurities of Czochralski silicon with annealing by positron annihilation

Positron annihilation lifetime experiments have been performed for B-doped p-type Czochralski silicon (CZ-SI) wafers irradiated at 300 K with 1 MeV el ectrons with fluences between 10(14) and 10(17) e/cm(2). In order to examin e the thermal behavior of defects having shorter lifetime than that of the bulk, isochronal annealing experiments were carried out from 300 K to 900 K . The measurements were performed at 100 K to improve the positron trapping rates for defects. It is found that components having longer lifetime than that of the bulk behave differently, and they comprise by thermal donors ( TD):md divacancies (V-2). The short-lifetime component observed in the pres ent experiments is responsible for a complex defect with impure interstitia l oxygen atoms, doped B atoms and vacancies. The short-lifetime defects cha nge into vacancy-type defects and thermal donors in certain ranges of annea ling temperatures.