Raman scattering evaluation of lattice damage and electrical activity in Be-implanted GaAs

Journal Article · Sun Nov 01 00:00:00 EST 1987 · J. Appl. Phys.; (United States)

DOI:https://doi.org/10.1063/1.339237· OSTI ID:6391415

Gargouri, M; Prevot, B; Schwab, C

Systematic Raman scattering experiments were carried out on (001) GaAs implanted with 70-keV Be/sup +/ ions both after implantation for samples subjected to fluences spanning the 10/sup 13/--10/sup 15/ cm/sup -2/ range and after successive isochronal thermal annealing steps performed between 200 and 900 /sup 0/C for a selected series of Be doses. The implantation-induced damages were observed via the modifications with increasing fluence, of the first-order Raman line parameters (mainly for the LO peak) classified in terms of mode energy softening and linewidth increase. These modifications were quantitatively accounted for within the spatial coherence-length reduction formalism, which makes it possible to evaluate the mean size of unperturbed regions in as-implanted GaAs. Upon successive thermal treatments, the implanted layers were found to recover their crystalline perfection at a temperature as low as 500 /sup 0/C. Above this temperature the Be electrical activation is evidenced by the sudden and drastic modification of only the ''longitudinal'' response, which is interpreted as due to the coupling between the LO phonon and an overdamped plasmon. The detailed analysis of the coupled-mode behavior is presented in the case of p-doped GaAs. From the Raman line-shape analysis, including a near-surface free-carrier depleted zone, we have obtained information about the electrical properties of the layer in terms of carrier density and mobility. It is further shown that in the case of strong damping, the ratio ..omega../sup 2//sub p//GAMMA/sub p/, where ..omega../sub p/ and GAMMA/sub p/ are, respectively, the plasmon frequency and damping, is a pertinent quantity since it is proportional to the electrical conductivity.

• Research Organization: Laboratoire de Spectroscopie et d'Optique du Corps Solide, Unite associee au CNRS no. 232, Universite Louis Pasteur, 5, rue de l'Universite, 67084 Strasbourg Cedex, France
• OSTI ID: 6391415
• Journal Information: J. Appl. Phys.; (United States), Vol. 62:9
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
GALLIUM ARSENIDES
PHYSICAL RADIATION EFFECTS
RAMAN SPECTROSCOPY
DAMAGE
ELECTRICAL PROPERTIES
HEAT TREATMENTS
HELIUM IONS
ION IMPLANTATION
LAYERS
LINE WIDTHS
PLASMONS
VERY HIGH TEMPERATURE
ARSENIC COMPOUNDS
ARSENIDES
CHARGED PARTICLES
GALLIUM COMPOUNDS
IONS
LASER SPECTROSCOPY
PHYSICAL PROPERTIES
PNICTIDES
QUASI PARTICLES
RADIATION EFFECTS
SPECTROSCOPY
360605* - Materials- Radiation Effects