Strain relaxation of GaAs/Ge crystals on patterned Si substrates

Journal Article · Mon Jan 13 00:00:00 EST 2014 · Applied Physics Letters

DOI:https://doi.org/10.1063/1.4861864· OSTI ID:22275724

Kreiliger, T.; Falub, C. V.; Känel, H. von ^[1]; Isa, F.; Isella, G. ^[2]; Salvalaglio, M.; Miglio, L. ^[3]; Wewior, L.; Fuster, D.; Alén, B. ^[4]; Richter, M.; Uccelli, E. ^[5]; Niedermann, P.; Neels, A.; Dommann, A. ^[6]; Mancarella, F. ^[7]

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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)

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.

• OSTI ID: 22275724
• Journal Information: Applied Physics Letters, Vol. 104, Issue 2; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0003-6951
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CHEMICAL VAPOR DEPOSITION
CRYSTALS
FINITE ELEMENT METHOD
GALLIUM ARSENIDES
PHOTOLUMINESCENCE
SCANNING ELECTRON MICROSCOPY
VAPOR PHASE EPITAXY
X-RAY DIFFRACTION