An electron paramagnetic resonance study of proton-irradiated material revealed a new bistable O-related complex. Three electron paramagnetic resonance centers (Si-A18) and 2 new centers, Si-AA13 with C3v symmetry and Si-AA14 (C1), corresponded to the A+, B+ and B- charge states, respectively, of this bistable complex. An A  B transition was observed at about 160 to 180 K, and a B  A transition resulted, at 77K, from illumination with 1eV light. A stress-induced defect alignment was also studied. On the basis of the hyperfine structures of the A18 and AA13 spectra, as well as stress alignments and correlations with deep-level transient spectroscopic data, the bistable center was tentatively proposed to be an interstitial complex: Sii-Oi. Upon annealing at about 250K, the bistable complex disappeared and a new center, AA12, grew. The results confirmed that AA12 might be a self-interstitial related defect.

K.A.Abdullin, B.N.Mukashev, J.V.Gorelkinskii: Materials Science Forum, 1995, 196-201, 1007-12