Electron paramagnetic resonance study of S2 defects in hydrogen-implanted silicon

Electron paramagnetic resonance spectra of S2 paramagnetic center in Float zone silicon (FZ-Si) and Czochralski silicon (CZ-Si) produced by H-2(+) ion-implantation and by subsequent annealing have been studied. At room temperature the spectrum exhibits an isotropic line g = 2.0066 +/- 0.0002, which, then broadens and transforms in a complex spectrum at 120 K. This complex spectrum can be decomposed into isotropic and anisotropic component. The relative concentration of anisotropic component is larger in CZ-Si and smaller in FZ-Si than the respective isotropic component. The g tensor evaluated from the anisotropic component at 120 K shows that the spectrum originated from the center with trigonal symmetry. The involvement of hydrogen and oxygen atoms in the center has been discussed, It is suggested that the S2 center is developed in the multi-vacancy defect containing oxygen and hydrogen atoms. From reversible thermal effect of the linewidth narrowing the motional properties of the dangling bond in the S2 center is described by the activation energy of 0.03 eV, (C) 2000 Elsevier Science B.V. All rights reserved.