On the donor activity of oxygen in silicon at temperatures from 500 to 800 °C

Results of Hall effect measurements are given on the donor activity of oxygen in silicon due to heat treatment at temperatures 500 to 800 °C. It is shown that, the different activation processes of donor formation are correlated to the thermal ionization energy ED. For heat treatments at 500 and 525 °C, respectively, the same dependence on duration of heat treatment t, ED = ED(t), qualitatively is found as for the 450 °C-thermal donor. Owing to the heat treatment in the temperature range 550 to 600 °C ED changes from about 15 to 35 meV, and at temperatures T ≧ 650 °C in the range of about 30 to 120 meV, respectively. Obviously, several activation processes correspond to different kinds of donor centres.