Luminescence and EPR studies of defects in Si-SiO

Co-sputtered Si-rich SiO2 films annealed at 1150 °C are studied by photoluminescence and EPR methods. It is found that the emission spectrum of as-prepared samples contains one broad infrared band. It is shown that one-year aging in ambient air and low-temperature annealing in an oxygen atmosphere leads to an increase in the infrared band intensity and the appearance of additional bands with maxima at 1.7 eV, 2.06 eV and 2.3 eV while annealing in a hydrogen atmosphere results in the decrease of the 1.7 eV and 2.06 eV band intensities. A correlation between the 1.7-eV band intensity and the EPR signal from EX-centers is found to exist. The decrease of crystallite sizes results in a high-energy shift of the infrared band while the peak positions of the other ones (at 1.7 eV, 2.06 eV and 2.3 eV) do not change. The infrared band is ascribed to recombination in Si crystallites while the others are attributed to silicon oxide defects, the 1.7-eV and 2.06-eV bands being due to oxygen-excess defects such as EX-center and NBOHC

Role of silicon oxide defects in emission process of Si-SiO₂ systems

Si-rich SiO₂ films prepared by r.f. magnetron sputtering and annealed at 1150 °C are investigated by photoluminescence, Raman and EPR methods. It is found that emission spectrum of as-prepared samples contains one broad infrared band. It is shown that one-year aging in ambient air and low-temperature annealing in oxygen atmosphere lead to the increase of infrared band intensity and the appearance of additional bands with maxima at 1.7 eV, 2.06 eV and 2.3 eV while annealing in hydrogen atmosphere results in the decrease of 1.7 eV and 2.06 eV band intensities. The decrease of crystallite sizes results in high-energy shift of infrared band while the peak positions of another ones (at 1.7, 2.06 and 2.3 eV) do not change. It is concluded that infrared band is connected with Si crystallites while another ones can be ascribed to silicon oxide defects, 1.7 and 2.06 eV bands being ascribed to oxygen-excess defects such as EX- and non-bridging oxygen hole centres