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Title: GaAs/Ge crystals grown on Si substrates patterned down to the micron scale

Monolithic integration of III-V compounds into high density Si integrated circuits is a key technological challenge for the next generation of optoelectronic devices. In this work, we report on the metal organic vapor phase epitaxy growth of strain-free GaAs crystals on Si substrates patterned down to the micron scale. The differences in thermal expansion coefficient and lattice parameter are adapted by a 2-μm-thick intermediate Ge layer grown by low-energy plasma enhanced chemical vapor deposition. The GaAs crystals evolve during growth towards a pyramidal shape, with lateral facets composed of (111) planes and an apex formed by (137) and (001) surfaces. The influence of the anisotropic GaAs growth kinetics on the final morphology is highlighted by means of scanning and transmission electron microscopy measurements. The effect of the Si pattern geometry, substrate orientation, and crystal aspect ratio on the GaAs structural properties was investigated by means of high resolution X-ray diffraction. The thermal strain relaxation process of GaAs crystals with different aspect ratio is discussed within the framework of linear elasticity theory by Finite Element Method simulations based on realistic geometries extracted from cross-sectional scanning electron microscopy images.
Authors:
; ; ;  [1] ;  [2] ;  [3] ; ;  [4] ;  [1] ;  [5] ; ;  [6] ;  [7]
  1. Laboratory for Solid State Physics, ETH Zürich, Otto-Stern-Weg. 1, CH-8093 Zürich (Switzerland)
  2. Department of Condensed Matter Physics, Masaryk University, Kotlářská 2, CZ-61137 Brno (Czech Republic)
  3. (Czech Republic)
  4. L-NESS, Department of Materials Science, Università di Milano-Bicocca, Via R. Cozzi 55, I-20125 Milano (Italy)
  5. (Italy)
  6. Scientific Center for Optical and Electron Microscopy (ScopeM), ETH Zürich, Auguste-Piccard-Hof 1, CH-8093 Zürich (Switzerland)
  7. L-NESS and Department of Physics, Politecnico di Milano, via Anzani 42, I-22100 Como (Italy)
Publication Date:
OSTI Identifier:
22494983
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 119; Journal Issue: 5; Other Information: (c) 2016 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ASPECT RATIO; CHEMICAL VAPOR DEPOSITION; CRYSTALS; FINITE ELEMENT METHOD; GALLIUM ARSENIDES; LATTICE PARAMETERS; OPTOELECTRONIC DEVICES; SCANNING ELECTRON MICROSCOPY; SUBSTRATES; TRANSMISSION ELECTRON MICROSCOPY; VAPOR PHASE EPITAXY; X-RAY DIFFRACTION