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Nucleation, Growth, and Strain Relaxation of Lattice-Mismatched III-V Semiconductor Epitaxial LayersWe have investigated the early stages of evolution of highly strained 2-D InAs layers and 3-D InAs islands grown by metal-organic chemical vapor deposition (MOCVD) on (100) and (111) B GaAs substrates. The InAs epilayer / GaAs substrate combination has been chosen because the lattice-mismatch is severe (approx. 7.20%), yet these materials are otherwise very similar. By examining InAs-on-GaAs composites Instead of the more common In(x)Ga(1-x)As alloy, we remove an additional degree of freedom (x) and thereby simplify data interpretation. A matrix of experiments is described in which the MOCVD growth parameters -- susceptor temperature, TMIn flux, and AsH3 flux -- have been varied over a wide range. Scanning electron microscopy, atomic force microscopy, transmission electron microscopy, and electron microprobe analysis have been employed to observe the thin film surface morphology. In the case of 3-D growth, we have extracted activation energies and power-dependent exponents that characterize the nucleation process. As a consequence, optimized growth conditions have been identified for depositing approx. 250 A thick (100) and (111)B oriented InAs layers with relatively smooth surfaces. Together with preliminary data on the strain relaxation of these layers, the above results on the evolution of thin InAs films indicate that the (111)B orientation is particularly promising for yielding lattice-mismatched films that are fully relaxed with only misfit dislocations at the epilayer / substrate interface.
Document ID
20000032853
Acquisition Source
Headquarters
Document Type
Conference Paper
Authors
Welser, R. E.
(Yale Univ. New Haven, CT United States)
Guido, L. J.
(Yale Univ. New Haven, CT United States)
Date Acquired
August 19, 2013
Publication Date
September 1, 1994
Publication Information
Publication: Proceedings of the 13th Space Photovoltaic Research and Technology Conference (SPRAT 13)
Subject Category
Solid-State Physics
Funding Number(s)
CONTRACT_GRANT: NSF ECS-92-53760
CONTRACT_GRANT: NGT-50832
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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