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Title: Fabrication of GeSn-multiple quantum wells by overgrowth of Sn on Ge by using molecular beam epitaxy

We report on the fabrication and structural characterization of epitaxially grown ultra-thin layers of Sn on Ge virtual substrates (Si buffer layer overgrown by a 50 nm thick Ge epilayer followed by an annealing step). Samples with 1 to 5 monolayers of Sn on Ge virtual substrates were grown using solid source molecular beam epitaxy and characterized by atomic force microscopy. We determined the critical thickness at which the transition from two-dimensional to three-dimensional growth occurs. This transition is due to the large lattice mismatch between Ge and Sn (≈14.7%). By depositing Ge on top of Sn layers, which have thicknesses at or just below the critical thickness, we were able to fabricate ultra-narrow GeSn multi-quantum-well structures that are fully embedded in Ge. We report results on samples with one and ten GeSn wells separated by 5 and 10 nm thick Ge spacer layers that were characterized by high resolution transmission electron microscopy and X-ray diffraction. We discuss the structure and material intermixing observed in the samples.
Authors:
 [1] ;  [2] ; ;  [1] ;  [3] ;  [4] ; ;  [5] ; ;  [6]
  1. Institute for Semiconductor Engineering, University of Stuttgart, 70569 Stuttgart (Germany)
  2. (Portugal)
  3. CACTI, Univ. de Vigo, Campus Universitario Lagoas Marcosende 15, Vigo (Spain)
  4. IHP GmbH, Innovations for High Performance Microelectronics, Leibniz-Institut für innovative Mikroelektronik, Im Technologiepark 25, 15236 Frankfurt (Oder) (Germany)
  5. Centre of Physics, University of Minho, Campus de Gualtar, 4710-057 Braga (Portugal)
  6. Dpto. Fisica Aplicada, Univ. de Vigo, Rua Maxwell s/n, Campus Universitario Lagoas Marcosende, Vigo (Spain)
Publication Date:
OSTI Identifier:
22486302
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 107; Journal Issue: 26; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ANNEALING; ATOMIC FORCE MICROSCOPY; CRYSTAL DEFECTS; FABRICATION; LAYERS; MOLECULAR BEAM EPITAXY; QUANTUM WELLS; SUBSTRATES; THICKNESS; THIN FILMS; TRANSMISSION ELECTRON MICROSCOPY; TWO-DIMENSIONAL SYSTEMS; X-RAY DIFFRACTION