ORIGIN OF INFRARED BANDS IN NEUTRON-IRRADIATED SILICON

Infrared absorption measurements were made of the localized vibrationa l modes due to defects produced in Czochralski-grown Si material after irradiation with fast neutrons and subsequent thermal treatments. The investigation was focused, in particular, on three satellite bands in the region of the A center, located at 839, 833 and 824 cm(-1) respec tively, the annealing behavior of which was carefully monitored. Corre lation of our results with previous infrared, electron paramagnetic re sonance and positron annihilation studies favors attributing these ban ds to the V2O, V3O2 and V2O2 defects respectively. In addition, semiem pirical calculations were carried out for the vibrational frequencies of these defects, and the predicted values are in agreement with the a bove assignments. (C) 1997 American Institute of Physics.