Strain and composition profiles of self-assembled Ge/Si(001) islands

Journal Article · Mon Aug 01 04:00:00 EDT 2005 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.2006229· OSTI ID:20714021

Alonso, M I; Calle, M de la; Osso, J O; Garriga, M; Goni, A R ^[1]

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1. Institut de Ciencia de Materials de Barcelona, Consejo Superior de Investigaciones Cientificas (CSIC), Campus de la Universitat Autonoma de Barcelona (UAB), 08193 Bellaterra (Spain)

Epitaxial growth of Ge/Si(001) in the Stranski-Krastanow regime results in the formation of island ensembles with various sizes and morphologies. During formation there is generally a strain-driven Si diffusion into the Ge islands. We investigate this issue in an epilayer grown by molecular-beam epitaxy containing pyramids, domes, and superdomes. A series of samples obtained by wet chemical etching of the original layer for different times in diluted hydrogen peroxide was evaluated by atomic force microscopy, spectroscopic ellipsometry, and Raman scattering. The average island composition as etching proceeds becomes Si richer, changing from about Si{sub 0.2}Ge{sub 0.8} to Si{sub 0.35}Ge{sub 0.65}, whereas the lattice strain increases, in particular, the material at the island summits is essentially relaxed. The composition of the wetting layer is nearly Si{sub 0.45}Ge{sub 0.55}. The results also reveal relatively Si-rich nuclei of a uniform size of {approx_equal}100 nm for all domes and superdomes, in accordance with a dislocation-induced growth mechanism of superdomes.

• OSTI ID: 20714021
• Journal Information: Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 3 Vol. 98; ISSN JAPIAU; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ATOMIC FORCE MICROSCOPY
CRYSTAL GROWTH
DIFFUSION
DISLOCATIONS
ELLIPSOMETRY
ETCHING
GERMANIUM
HYDROGEN PEROXIDE
MAGNETIC ISLANDS
MOLECULAR BEAM EPITAXY
MORPHOLOGY
RAMAN EFFECT
RAMAN SPECTRA
SEMICONDUCTOR MATERIALS
SILICON
STRAINS
SURFACES