INTERACTIONS OF POINT DEFECTS WITH IMPURITIES IN SILICON

The minority carrier lifetime in gamma-irradiated silicon crystals was studied. In F. Z. n type crystals containing phosphorous, arsenic, antimony or bismuth, there are two annealing stages in the temperature range 100-280°C and in both stages there is strong dependency of activation energies Ea and frequency factors on the atomic size of the impurity. The relationship between Ea and covalent radii of the impurity atom can be experimentally expressed in linear functions. The defect which anneals in the lower temperature stage is a complex of donor atoms associated with a vacancy type defect. Si-E center anneals in the higher temperature stage and the values of activation energies completely agree with those obtained by Watkins et al. in their experiments of reorientation of donor-vacancy axis. The defects of both stages are considered to migrate to the sinks of oxygen after jumps of about 105. It is very interesting to note that this study shows only one example of an impurity atom which moves with a vacancy in silicon without breaking up. © 1969, THE PHYSICAL SOCIETY OF JAPAN. All rights reserved.