Photoluminescence and paramagnetic defects in silicon-implanted silicon dioxide layers

Thermally grown SiO2 layers on Si substrates implanted with Si+ ions with a dose of 6 x 10(16) cm(-2) were studied by the techniques of photoluminesce nce, electron paramagnetic resonance (EPR), and low-frequency Raman scatter ing. Distinct oxygen-vacancy associated defects in SiO2 and non-bridging ox ygen hole centers were identified by EPR. The luminescence intensity in the 620 nm range was found to correlate with the number of these defects. The low-frequency Raman scattering technique was used to estimate the average s ize of the Si nanocrystallites formed after the implantation and thermal an nealing at T > 1100 degrees C, which are responsible for the photoluminesce nce band with a maximum at 740 nm. The intensity of this band can be signif icantly enhanced by an additional treatment of the samples in a low-tempera ture RF plasma. (C) 1999 Elsevier Science B.V. All rights reserved.