Internal strains and crystal structure of the layers in AlGaN/GaN heterostructures grown on a sapphire substrate

In this paper, we investigate the structural properties of AlGaN/GaN heterostructures grown by metal organic chemical vapor deposition on sapphire substrates with different thicknesses using high-resolution x-ray diffraction and Raman scattering methods. We discuss the microscopic nature of spatial-...

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Veröffentlicht in:Journal of applied physics 2009-03, Vol.105 (6), p.063515-063515-9
Hauptverfasser: Kladko, V. P., Kolomys, A. F., Slobodian, M. V., Strelchuk, V. V., Raycheva, V. G., Belyaev, A. E., Bukalov, S. S., Hardtdegen, H., Sydoruk, V. A., Klein, N., Vitusevich, S. A.
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Sprache:eng
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Zusammenfassung:In this paper, we investigate the structural properties of AlGaN/GaN heterostructures grown by metal organic chemical vapor deposition on sapphire substrates with different thicknesses using high-resolution x-ray diffraction and Raman scattering methods. We discuss the microscopic nature of spatial-inhomogeneous deformations and dislocation density in the structures. Microdeformations within mosaic blocks and the sizes of regions of coherent diffraction are determined. We reveal a gradient depth distribution of deformations in the mosaic structure of nitride layers, as well as at the interface regions of the sapphire substrate on the microscale level using confocal micro-Raman spectroscopy. We determine that an increase in substrate thickness leads to a reduction in dislocation density in the layers and an increase in the elastic deformations. The features of the block structure of nitrides layers are shown to have a significant influence on their elastic properties.
ISSN:0021-8979
1089-7550
DOI:10.1063/1.3094022