New bistable oxygen-related complex in silicon

An electron-paramagnetic resonance (EPR) study of proton-irradiated silicon has revealed a new bistable oxygen-related complex. Three EPR centers - known Si-A18 and two new centers labeled Si-AA13 (C-3v-symmetry) and Si-AA14 (C-1) correspond to A(+), B+ and B-. charge states respectively of this bistable complex. A-->B transition is observed at similar to 160-180 K, B-->A transition is resulted at 77 K upon illumination with similar to 1 eV light. A stress induced defect alignment was also studied. Based on hyperfine structures of A18 and AA13 spectra as well as stress alignment and correlation with DLTS data we proposed tentative model of the bistable center as interstitial complex (Si-i-O-i). Upon annealing at similar to 250 K the bistable complex disappears and a new center labeled AA12 grows. Data confirmed that AA12 may be self-interstitial related defect are presented.