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Title: Elastic strain relaxation in axial Si/Ge whisker heterostructures

Abstract

The elastic behavior of molecular beam epitaxy-grown SiGe/Si(111) nanowhiskers (NWs) has been studied by means of electron microscopy, x-ray scattering, and numerical linear elasticity theory. Highly brilliant synchrotron radiation was applied to map the diffusely scattered intensity near the asymmetric (115) reciprocal lattice point. The larger lattice parameter with respect to the Si matrix causes a lateral lattice expansion within embedded Ge layers. This enables a clear separation of scattering due to NWs and laterally confined areas aside. Finite element calculations prove a lateral lattice compression in the Si matrix close to the NW apex above buried threefold and single Ge layer stacks. This suggests an incorporation probability, which additionally depends on the radial position within heteroepitaxial NWs.

Authors:
; ; ; ; ; ; ;  [1];  [2];  [2];  [2];  [3]
  1. Martin-Luther-Universitaet Halle-Wittenberg, Institut fuer Physik, Hoher Weg 8, D-06120 Halle (Germany)
  2. (Germany)
  3. (France)
Publication Date:
OSTI Identifier:
20957816
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. B, Condensed Matter and Materials Physics; Journal Volume: 75; Journal Issue: 16; Other Information: DOI: 10.1103/PhysRevB.75.161303; (c) 2007 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ASYMMETRY; ELASTICITY; ELECTRON MICROSCOPY; FINITE ELEMENT METHOD; GERMANIUM; GERMANIUM SILICIDES; HETEROJUNCTIONS; LATTICE PARAMETERS; LAYERS; MOLECULAR BEAM EPITAXY; NANOSTRUCTURES; RELAXATION; SEMICONDUCTOR MATERIALS; SILICON; STRAINS; SYNCHROTRON RADIATION; WHISKERS; X-RAY DIFFRACTION

Citation Formats

Hanke, M., Eisenschmidt, C., Werner, P., Zakharov, N. D., Syrowatka, F., Heyroth, F., Schaefer, P., Konovalov, O., Max-Planck Institut fuer Mikrostrukturphysik, Weinberg 2, D-06120 Halle, Interdisziplinaeres Zentrum fuer Materialwissenschaften, Heinrich-Damerow-Strasse 4, D-06120 Halle, Humboldt-Universitaet zu Berlin, Institut fuer Physik, Newtonstrasse 15, D-12489 Berlin, and European Synchrotron Radiation Facility, BP 220, F-38043 Grenoble Cedex. Elastic strain relaxation in axial Si/Ge whisker heterostructures. United States: N. p., 2007. Web. doi:10.1103/PHYSREVB.75.161303.
Hanke, M., Eisenschmidt, C., Werner, P., Zakharov, N. D., Syrowatka, F., Heyroth, F., Schaefer, P., Konovalov, O., Max-Planck Institut fuer Mikrostrukturphysik, Weinberg 2, D-06120 Halle, Interdisziplinaeres Zentrum fuer Materialwissenschaften, Heinrich-Damerow-Strasse 4, D-06120 Halle, Humboldt-Universitaet zu Berlin, Institut fuer Physik, Newtonstrasse 15, D-12489 Berlin, & European Synchrotron Radiation Facility, BP 220, F-38043 Grenoble Cedex. Elastic strain relaxation in axial Si/Ge whisker heterostructures. United States. doi:10.1103/PHYSREVB.75.161303.
Hanke, M., Eisenschmidt, C., Werner, P., Zakharov, N. D., Syrowatka, F., Heyroth, F., Schaefer, P., Konovalov, O., Max-Planck Institut fuer Mikrostrukturphysik, Weinberg 2, D-06120 Halle, Interdisziplinaeres Zentrum fuer Materialwissenschaften, Heinrich-Damerow-Strasse 4, D-06120 Halle, Humboldt-Universitaet zu Berlin, Institut fuer Physik, Newtonstrasse 15, D-12489 Berlin, and European Synchrotron Radiation Facility, BP 220, F-38043 Grenoble Cedex. Sun . "Elastic strain relaxation in axial Si/Ge whisker heterostructures". United States. doi:10.1103/PHYSREVB.75.161303.
@article{osti_20957816,
title = {Elastic strain relaxation in axial Si/Ge whisker heterostructures},
author = {Hanke, M. and Eisenschmidt, C. and Werner, P. and Zakharov, N. D. and Syrowatka, F. and Heyroth, F. and Schaefer, P. and Konovalov, O. and Max-Planck Institut fuer Mikrostrukturphysik, Weinberg 2, D-06120 Halle and Interdisziplinaeres Zentrum fuer Materialwissenschaften, Heinrich-Damerow-Strasse 4, D-06120 Halle and Humboldt-Universitaet zu Berlin, Institut fuer Physik, Newtonstrasse 15, D-12489 Berlin and European Synchrotron Radiation Facility, BP 220, F-38043 Grenoble Cedex},
abstractNote = {The elastic behavior of molecular beam epitaxy-grown SiGe/Si(111) nanowhiskers (NWs) has been studied by means of electron microscopy, x-ray scattering, and numerical linear elasticity theory. Highly brilliant synchrotron radiation was applied to map the diffusely scattered intensity near the asymmetric (115) reciprocal lattice point. The larger lattice parameter with respect to the Si matrix causes a lateral lattice expansion within embedded Ge layers. This enables a clear separation of scattering due to NWs and laterally confined areas aside. Finite element calculations prove a lateral lattice compression in the Si matrix close to the NW apex above buried threefold and single Ge layer stacks. This suggests an incorporation probability, which additionally depends on the radial position within heteroepitaxial NWs.},
doi = {10.1103/PHYSREVB.75.161303},
journal = {Physical Review. B, Condensed Matter and Materials Physics},
number = 16,
volume = 75,
place = {United States},
year = {Sun Apr 15 00:00:00 EDT 2007},
month = {Sun Apr 15 00:00:00 EDT 2007}
}
  • A mechanism of strain relief of pseudomorphic Si{sub 1-x}Ge{sub x}/Si(100) heterostructures by Si{sup +} ion implantation and annealing is proposed and analytically modeled. The degree of strain relaxation is presented as a function of Ge content and implantation and annealing parameters. Rutherford backscattering spectrometry/channeling, Raman spectroscopy, and transmission electron microscopy are employed to quantify the efficiency of the relaxation process and to examine the quality of the samples, respectively. The mechanism and the conditions for strain relaxation are discussed in terms of dislocation loop formation in the implanted range with emphasis on loop formation in the compressively strained SiGe layer.more » The detrimental effect of local amorphization of the SiGe layer on its relaxation and on strain transfer to the Si-cap layer is also addressed.« less
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  • The strain dependence of Si-Ge interdiffusion in epitaxial Si/Si{sub 1-y}Ge{sub y}/Si heterostructures on relaxed Si{sub 1-x}Ge{sub x} substrates has been studied using secondary ion mass spectrometry, Raman spectroscopy, and simulations. At 800 and 880 deg. C, significantly enhanced Si-Ge interdiffusion is observed in Si/Si{sub 1-y}Ge{sub y}/Si heterostructures (y=0.56, 0.45, and 0.3) with Si{sub 1-y}Ge{sub y} layers under compressive strain of -1%, compared to those under no strain. In contrast, tensile strain of 1% in Si{sub 0.70}Ge{sub 0.30} layer has no observable effect on interdiffusion in Si/Si{sub 0.70}Ge{sub 0.30}/Si heterostructures. These results are relevant to the device and process design ofmore » high mobility dual channel and heterostructure-on-insulator metal oxide semiconductor field effect transistors.« less
  • The abrupt heterointerfaces in the Si/Ge materials system presents useful possibilities for electronic device engineering because the band structure can be affected by strain induced by the lattice mismatch. In planar layers, heterointerfaces with abrupt composition changes are difficult to realize without introducing misfit dislocations. However, in catalytically grown nanowires, abrupt heterointerfaces can be fabricated by appropriate choice of the catalyst. Here we grow nanowires containing Si/Ge and Si/Ge/Si structures respectively with sub-1nm thick Ge "quantum wells" and we measure the interfacial strain fields using geometric phase analysis. Narrow Ge layers show radial strains of several percent, with a correspondingmore » dilation in the axial direction. Si/Ge interfaces show lattice rotation and curvature of the lattice planes. We conclude that high strains can be achieved, compared to what is possible in planar layers. In addition, we study the stability of these heterostructures under heating and electron beam irradiation. The strain and composition gradients are supposed to the cause of the instability for interdiffusion.« less
  • The formation of abrupt heterointerfaces in the Si/Ge materials system presents useful possibilities for electronic device engineering due to the effect on ban structure of strain induced by the lattice mismatch. In planar layers, heterointerfaces with abrupt composition changes are difficult to fabricate without introducing misfit dislocations. However, in catalytically grown nanowires, abrupt heterointerfaces can be fabricated by appropriate choice of the catalyst. Here we grow nanowires containing Si/Ge and Si/Ge/Si structures with sub-1 nm thick Ge “quantum wells” and we measure the interfacial strain fields using geometric phase analysis. Narrow Ge layers show radial compressive strains of several percent,more » with a corresponding dilation in the axial direction. At the Si/Ge interface, the stress change causes lattice rotation and curvature of the lattice planes. However, we find that these heterostructures are unstable to interdiffusion, presumably due to their strain and composition gradients. We discuss the implications of this instability for device applications.« less