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Proceedings Paper

Characterization of electrical and structural properties of ion-implanted GaAs by Raman scattering
Author(s): L. P. Avakyants; P. A. Polyakov; Vladimir S. Gorelik
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Paper Abstract

Raman spectra (RS) of GaAs implanted with 140 keV Si+ ions, both before and after annealing, were obtained at room temperature, in x(yz)x backscattering geometry, using the 514.5 nm line of Ar laser. The implantation-induced amorphous bands and LO-line shape changes were observed with increasing fluences from 1013 to 5 1014 cm-2. We explained the modifications of the spectra via disorder-induced selection rule breakdown and estimated nanocrystallite size for different fluences according to the mode of reduction of the spatial correlation length. For annealing studies implanted samples were caped with Si3N4 layer and annealed at 900 C for 20 min in hydrogen. After annealing, the amorphous bands have disappeared, and the new spectral features were observed. We explained the evolution of the spectra by the dopant activation, resulting in RS by phonon-plasmon coupled modes and RS by LO phonon, originating from the surface-depletion layer. We interpreted shifts of the coupled modes and LO intensity change as evidence of the carrier concentration variation with fluences. Experimental results were described by the Lindhard-Mermin dielectric function including the non-parabolicity of the conduction band, evaluated for the case, when Drude approximation is not available. From Raman line-shape analysis we have obtained that the value of carrier concentration were 1018 cm-3 for ion fluences 1013-5 1014 cm-2.

Paper Details

Date Published: 25 February 2000
PDF: 6 pages
Proc. SPIE 4070, ALT '99 International Conference on Advanced Laser Technologies, (25 February 2000); doi: 10.1117/12.378190
Show Author Affiliations
L. P. Avakyants, M.V. Lomonosov Moscow State Univ. (Russia)
P. A. Polyakov, Moscow State Univ. (Russia)
Vladimir S. Gorelik, P.N. Lebedev Physical Institute (Russia)

Published in SPIE Proceedings Vol. 4070:
ALT '99 International Conference on Advanced Laser Technologies
Vladimir I. Pustovoy; Vitali I. Konov, Editor(s)

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