Oxygen '96

Early Stages of Oxygen Precipitation in Silicon

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CARBON-HYDROGEN-OXYGEN(?) RELATED CENTRE RESPONSIBLE FOR THE PHOTOLUMINESCENCE I-LINE (0.965 eV).

J. E. Gower, A. N. Safonov, E. C. Lightowlers and G. Davies

Physics Department, King's College London, Strand, London WC2R 2LS, UK

The I-line luminescence centre with a zero-phonon transition at 0.965 eV is created when Czochralski silicon is annealed in the temperature range 400 to 600$^\circ$C. It has been reported previously that the photoluminescence intensity of the centre increases with carbon and oxygen concentration implying that both impurities are involved [1]. Recently, investigation of silicon deliberately doped with hydrogen- deuterium and carbon isotope mixtures have shown that the centre contains at least one carbon atom and one hydrogen atom [2]. In this paper we report high resolution luminescence measurements of the system under external field perturbations and in samples with various carbon and hydrogen isotope compositions. In addition to the zero-phonon I-line, the luminescence spectra contain a broad phonon-assisted side band and several local mode satellites. Temperature-controlled measurements reveal a zero-phonon transition at 2.38 meV higher energy than the I-line, which is associated with the excited electronic state. Uniaxial stress perturbations produce non-linear splitting of luminescence lines, consistent with monoclinic I symmetry of the centre. Although the structure of the centre is uncertain the mechanisms of formation and the energies of the local vibrational modes suggest that interstitial carbon is involved.

[1] N.S.Minaev, and A.V.Mudryi, Phys. Stat. Solidi A 68, 561 (1981).
[2] E.C.Lightowlers, R.C.Newman, and J.H.Tucker, Semicond. Sci. and Tech. 9, 1370 (1994).

Last modified: Wed Feb 28 19:00:15 GMT 1996 JG