EPR of defects in silicon-on-insulator structures formed by ion implantation. I. O⁺implantation

EPR measurements at X band and room temperature have been made of defects produced by implanting (100) and (111) silicon wafers with doses >1018 O- cm-2 using 300 keV O- and 400 keV O2+ ions and an implantation temperature of 500-600 degrees C. These doses are sufficient to form a buried SiO2 layer. The main features of the EPR spectra are attributed to three types of defect, with (i) g=2.0003(3), (ii) g=2.0013(2), g-=2.0082(2) with the axis parallel to any (111)-type direction and (iii) g=2.0054(3). The defects are suggested to be respectively (i) E'1 centres in the a-SiO2 layer, (ii) Pb0-like centres primarily at Si/SiO2 interfaces of SiO2 precipitates and (iii) amorphous silicon centres, possibly associated with oxygen. The angular dependence of the Pb0-like centre linewidth is measured and interpreted in terms of a spread in g-values. Annealing and etching studies have also been made.