Composition and strain in thin Si{sub 1-x}Ge{sub x} virtual substrates measured by micro-Raman spectroscopy and x-ray diffraction

Journal Article · Tue Feb 01 04:00:00 EST 2011 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.3536508· OSTI ID:21538077

Perova, T S; Wasyluk, J; Waldron, A ^[1]; Lyutovich, K; Kasper, E; Oehme, M ^[2]; Rode, K ^[3]

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1. Department of Electronic and Electrical Engineering, Trinity College, University of Dublin, Dublin 2 (Ireland)
2. Institut fuer Halbleitertechnik, Universitaet Stuttgart, Pfaffenwaldring 47, 70569 Stuttgart (Germany)
3. School of Physics, CRANN, Trinity College, University of Dublin, Dublin 2 (Ireland)

Micro-Raman spectroscopy was employed for the determination of the germanium content, x and strain, {epsilon}, in ultrathin SiGe virtual substrates grown directly on Si by molecular beam epitaxy. The growth of highly relaxed SiGe layers was achieved by the introduction of point defects at a very low temperature during the initial stage of growth. SiGe virtual substrates with thicknesses in the range 40-200 nm with a high Ge content (up to 50%) and degree of relaxation, r, in the range 20%-100% were investigated using micro-Raman spectroscopy and x-ray diffraction (XRD) techniques. The Ge content, x, and strain, {epsilon}, were estimated from equations describing Si-Si, Si-Ge, and Ge-Ge Raman vibrational modes, modified in this study for application to thin SiGe layers. The alteration of the experimentally derived equations from previous studies was performed using independent data for x and r obtained from XRD reciprocal space maps. A number of samples consisting of a strained-silicon (s-Si) layer deposited on a SiGe virtual substrate were also analyzed. The stress value for the s-Si varied from 0.54 to 2.75 GPa, depending on the Ge-content in the virtual substrates. These results are in good agreement with theoretically predicted values.

• OSTI ID: 21538077
• Journal Information: Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 3 Vol. 109; ISSN JAPIAU; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ALLOYS
BUFFERS
COHERENT SCATTERING
CRYSTAL DEFECTS
CRYSTAL GROWTH METHODS
CRYSTAL STRUCTURE
DECISION MAKING
DEMAND
DIFFRACTION
DISLOCATIONS
EPITAXY
FEEDBACK
FILMS
GERMANIUM ALLOYS
GERMANIUM COMPOUNDS
GERMANIUM SILICIDES
LASER SPECTROSCOPY
LAYERS
LINE DEFECTS
MATERIALS
MOLECULAR BEAM EPITAXY
POINT DEFECTS
PRESSURE RANGE
PRESSURE RANGE GIGA PA
RAMAN SPECTRA
RAMAN SPECTROSCOPY
RELAXATION
SCATTERING
SEMICONDUCTOR MATERIALS
SILICIDES
SILICON ALLOYS
SILICON COMPOUNDS
SPECTRA
SPECTROSCOPY
STRAINS
SUBSTRATES
THIN FILMS
X-RAY DIFFRACTION