Annealing studies of vacancies in proton irradiated silicon

Annealing of vacancies produced by heavy proton irradiation of float-zone (Fz) and P-doped Czochralski-grown (Cz) silicon has been investigated by positron lifetime spectroscopy. In Fz-Si divacancies are retained after irradiation, and these defects are completely annealed out at 700 °C. In Cz P-doped silicon, impurities are found to enhance both the amount of retained vacancies as well as the tendency for vacancy clustering. Two annealing stages appear at 100 °C and close to 450 °C which seem to be a result of interstitial migration. Vacancy migration takes place in a wide temperature range between 100 and 1000 °C.