Photoluminescence due to oxygen precipitates distinguished from the D lines in annealed Si

Highly spatially resolved mapping of deep-level photoluminescence in annealed Czochralski-grown Si crystals has revealed for the first time that the D1/D2 lines at low temperatures show the opposite intensity contrast around dislocations with respect to the 0.77 eV band observed commonly at room temperature. The intensity of the D1/D2 lines decreases on the dislocation lines in the same way as the cathodoluminescence image of the D1/D2 lines in a plastically deformed float-zone Si crystal. The 0.77 eV band is renamed D-b band, since the peak shifts parallel to the bandgap with temperature. The positive correlation between the D-b band intensity and the precipitated oxygen concentration and the agreement of their distributions lead us to suggest that the D-b band is associated with the oxygen precipitation. The increase of the D-b band on the dislocation lines is due to the preferential precipitation of oxygen.