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Title: Strain relaxation of GaAs/Ge crystals on patterned Si substrates

We report on the mask-less integration of GaAs crystals several microns in size on patterned Si substrates by metal organic vapor phase epitaxy. The lattice parameter mismatch is bridged by first growing 2-μm-tall intermediate Ge mesas on 8-μm-tall Si pillars by low-energy plasma enhanced chemical vapor deposition. We investigate the morphological evolution of the GaAs crystals towards full pyramids exhibiting energetically stable (111) facets with decreasing Si pillar size. The release of the strain induced by the mismatch of thermal expansion coefficients in the GaAs crystals has been studied by X-ray diffraction and photoluminescence measurements. The strain release mechanism is discussed within the framework of linear elasticity theory by Finite Element Method simulations, based on realistic geometries extracted from scanning electron microscopy images.
Authors:
; ; ;  [1] ; ;  [2] ; ;  [3] ; ; ;  [4] ; ;  [5] ; ; ;  [6] ;  [7]
  1. Laboratory for Solid State Physics, ETH Zürich, Otto-Stern-Weg 1, CH-8093 Zürich (Switzerland)
  2. L-NESS, Department of Physics, Politecnico di Milano, via Anzani 42, I-22100 Como (Italy)
  3. L-NESS, Department of Materials Science, Università di Milano-Bicocca, via Cozzi 55, I-20125 Milano (Italy)
  4. IMM, Instituto de Microelectrónica de Madrid (CNM, CSIC), C/Isaac Newton 8, E-28760 Tres Cantos, Madrid (Spain)
  5. Functional Materials Group, IBM Research-Zürich, Säumerstrasse 4, CH-8803 Rüschlikon (Switzerland)
  6. Centre Suisse d'Electronique et Microtechnique, Jaquet-Droz 1, CH-2002 Neuchatel (Switzerland)
  7. CNR-IMM of Bologna, Via Gobetti 101, I-40129 Bologna (Italy)
Publication Date:
OSTI Identifier:
22275724
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 104; Journal Issue: 2; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; CHEMICAL VAPOR DEPOSITION; CRYSTALS; FINITE ELEMENT METHOD; GALLIUM ARSENIDES; PHOTOLUMINESCENCE; SCANNING ELECTRON MICROSCOPY; VAPOR PHASE EPITAXY; X-RAY DIFFRACTION