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

Kladko, V.P.; Raycheva, V.G.; Sydoruk, V. A.; Strelchuk, V.V.; Slobodian, M.V.; Klein, N.; Bukalov, S.S.; Vitusevich, S. A.; Hardtdegen, H.; Belyaev, A.E.; Kolomys, A.F.

doi:10.1063/1.3094022

Journal Article

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

Kladko, V. P. ; Kolomys, A. F. ; Slobodian, M. V. ; Strelchuk, V. V. ; Raycheva, V. G. ; Belyaev, A. E. ; Bukalov, S. S. ; Hardtdegen, H.FZJ* ; Sydoruk, V. A.FZJ* ; Klein, N.FZJ* ; Vitusevich, S. A.FZJ*

2009
American Institute of Physics Melville, NY

Journal of applied physics 105, 063515-1-9 (2009) [10.1063/1.3094022]

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Please use a persistent id in citations: http://hdl.handle.net/2128/17255 doi:10.1063/1.3094022

Abstract: 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.

Keyword(s): J ; aluminium compounds (auto) ; crystal structure (auto) ; dislocation density (auto) ; elastic deformation (auto) ; gallium compounds (auto) ; III-V semiconductors (auto) ; internal stresses (auto) ; MOCVD (auto) ; mosaic structure (auto) ; Raman spectra (auto) ; semiconductor epitaxial layers (auto) ; semiconductor growth (auto) ; semiconductor heterojunctions (auto) ; wide band gap semiconductors (auto) ; X-ray diffraction (auto)