Defects in buried SiO2 films in Si formed by implantation of oxygen ions were characterized by photoluminescence (PL) excited by KrF (5.0 eV) excimer laser and synchrotron radiation. Two PL bands were observed at 4.3 and 2.7 eV. The 4.3 eV band has two PL excitation bands at 5.0 and 7.4 eV, and its decay time is 4.0 ns for the 5.0 eV excitation and 2.4 ns for the 7.4 eV excitation. The decay time of the 2.1 eV PL band is found to be 9.7 ms. These results are very similar to those for the 4.3 eV and the 2.1 eV PL bands, which are observed in bulk silica glass of an oxygen-deficient type and attributed to the oxygen vacancy. Through the change in the PL intensity with the film thickness, the buried SiO2 film is considered to contain the oxygen vacancy defects in a high amount throughout the oxide.
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