Relaxation and critical strain for maximum In incorporation in AlInGaN on GaN grown by metal organic vapour phase epitaxy

Journal Article · Thu Nov 01 00:00:00 EDT 2012 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.4764342· OSTI ID:22089566

Reuters, Benjamin; Finken, M.; Wille, A.; Kalisch, H.; Vescan, A. ^[1]; Hollaender, B. ^[2]; Heuken, M. ^[1]

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1. RWTH Aachen University, GaN Device Technology, Sommerfeldstrasse 24, 52074 Aachen (Germany)
2. Juelich Aachen Research Alliance, JARA-FIT, Wilhelm-Johnen-Strasse, 52428 Juelich (Germany)

Quaternary AlInGaN layers were grown on conventional GaN buffer layers on sapphire by metal organic vapour phase epitaxy at different surface temperatures and different reactor pressures with constant precursor flow conditions. A wide range in compositions within 30-62% Al, 5-29% In, and 23-53% Ga was covered, which leads to different strain states from high tensile to high compressive. From high-resolution x-ray diffraction and Rutherford backscattering spectrometry, we determined the compositions, strain states, and crystal quality of the AlInGaN layers. Atomic force microscopy measurements were performed to characterize the surface morphology. A critical strain value for maximum In incorporation near the AlInGaN/GaN interface is presented. For compressively strained layers, In incorporation is limited at the interface as residual strain cannot exceed an empirical critical value of about 1.1%. Relaxation occurs at about 15 nm thickness accompanied by strong In pulling. Tensile strained layers can be grown pseudomorphically up to 70 nm at a strain state of 0.96%. A model for relaxation in compressively strained AlInGaN with virtual discrete sub-layers, which illustrates the gradually changing lattice constant during stress reduction is presented.

• OSTI ID: 22089566
• Journal Information: Journal of Applied Physics, Vol. 112, Issue 9; Other Information: (c) 2012 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM COMPOUNDS
ATOMIC FORCE MICROSCOPY
CHEMICAL VAPOR DEPOSITION
COMPRESSION STRENGTH
GALLIUM COMPOUNDS
GALLIUM NITRIDES
INDIUM COMPOUNDS
INTERFACES
LATTICE PARAMETERS
LAYERS
NITROGEN COMPOUNDS
ORGANOMETALLIC COMPOUNDS
RUTHERFORD BACKSCATTERING SPECTROSCOPY
SEMICONDUCTOR MATERIALS
STRAINS
TENSILE PROPERTIES
THICKNESS
VAPOR PHASE EPITAXY
X-RAY DIFFRACTION