New oxygen-related EPR spectra in proton-irradiated silicon

An electron-paramagnetic resonance (EPR) study of proton-irradiated silicon has revealed two new EPR spectra labeled Si-AA13 and Si-AA14. Spectrum AA13 has C3v symmetry (g⊥ = 1.9985 and g⊥ = 2.0024 ± 0.0002), AA14 C1 symmetry. These spectra correspond to positive (B+) and negative (B−) charge states respectively of a bistable defect in the B configuration. Another metastable configuration (labeled A) in positive charge state creates the known EPR spectrum Si-A18. Reversible transitions and electronic levels of the metastable defect are studied. A tentative model for this center is proposed: a self-interstitial—oxygen-interstitial complex (SiiOi).