ISOCHRONAL ANNEALING STUDIES OF THE OXYGEN-VACANCY CENTERS IN NEUTRON-IRRADIATED SI

The infrared spectra of room-temperature, neutron-irradiated, Czochral ski-grown Si were investigated. During annealing, the 827 cm(-1) VO de fect band decreases, and another band at 885 cm(-1) generally attribut ed to the VO2 centre increases. The kinetics of the evolution of these two defects was investigated. The decay of VO is dominated by a secon d-order reaction (VO + Si-i --> O-i) with an activation energy 1.70 eV . The growth of VO2 exhibits two stages. Below 360 degrees C, a first- order reaction (VO + O-i --> VO2) with an activating energy of 1.46 eV or a second-order reaction (VO + VO --> VO2 + V) with an activation e nergy of 1.96 eV could fit the data. The two cases are considered and discussed. The analysis goes further taking into account the more real istic case that both reactions occur in parallel. Values of 2.1 and 2. 0 eV were derived, respectively. Above 360 degrees C, the phenomenon i s not well understood, as other factors might also be at work which ma nifest their presence more profoundly above this temperature.