Hydrogen-induced extended complexes in silicon

New EPR spectrum, labeled Si-AA17, forms upon annealing at greater than or equal to 200 degrees C in irradiated high-purity hydrogen-containing silico n and is stable up to similar to 450 degrees C. The AA17 defect has D-34 sy mmetry, electronic spin S = 1 and it is paramagnetic in a neutral charge st ate. An analysis of Si-29 hf interaction has shown that 62% of the resonant wave function belongs to two equivalent silicon atoms. The magnitude of ze ro-field splitting (D = 16.8 MHz) indicates that the distance between two e quivalent Si sites (spins) creating the S = 1 state is similar to 12 Angstr om along the (1 1 1) axis. Piezospectroscopic measurements have also shown that vacancy-like defect should be sited between equivalent Si atoms. Tenta tive model of the defect is the (1 1 1) planar hexavacancy centered between two (1 1 1) dangling Si bonds separated by similar to 12 Angstrom. Each of these dangling bonds is formed as a result of saturation of the nearest Si atom by one hydrogen. Si-AA1 EPR spectrum associated with the formation of self-interstitial aggregates is observed simultaneously with the Si-AA17. (C) 1999 Elsevier Science B.V. All rights reserved.