THEORETICAL AND ISOTOPIC INFRARED-ABSORPTION INVESTIGATIONS OF NITROGEN-OXYGEN DEFECTS IN SILICON

The vibrational spectroscopy of NNO defects in Si introduced by O-16, N-14 and N-15 ion implantation is studied, and especially the N-isotop ic shifts of the localized vibrational modes. These investigations sho w that the local modes of the three impurity atoms comprising the defe ct are only weakly coupled dynamically. Ab initio cluster calculations of the local mode frequencies of the defect are performed. Several mo dels are investigated, and the model consisting of a bridging O atom a djacent to the N pair defect accounts for its dynamic properties.