Influence of alloy composition and interlayer thickness on twist and tilt mosaic in Al<SUB>x</SUB>Ga<SUB>1-x</SUB>N/AlN/GaN heterostructures

Lafford, T.A.; Parbrook, P.J.; Tanner, B.K.

Abstract

High-resolution x-ray diffraction, in surface symmetric, skew symmetric, and grazing incidence in-plane diffraction geometries, has been used to investigate the effect of an AlN interlayer between micron thick GaN and AlxGa1–xN layers grown by metalorganic vapor phase epitaxy on basal plane sapphire. No change is found in the tilt mosaic (threading screw dislocation density) with thickness or Al fraction x of the upper layer. A linear increase in the twist mosaic (threading edge dislocation density) was observed as a function of interlayer thickness and x. For all samples the twist mosaic of the AlGaN was significantly greater, by at least a factor of two, than that of the GaN layer. With increasing interlayer thickness the in-plane lattice parameter of the AlGaN decreased. The results are explained in terms of extra threading edge dislocations resulting from relaxation at the GaN/AlN interface.

Citation

Lafford, T., Parbrook, P., & Tanner, B. (2003). Influence of alloy composition and interlayer thickness on twist and tilt mosaic in AlxGa1-xN/AlN/GaN heterostructures. Applied Physics Letters, 83(26), 5434-5436. https://doi.org/10.1063/1.1637717

• Journal Article Type: Article
• Publication Date: Dec 29, 2003
• Deposit Date: Jan 9, 2009
• Publicly Available Date: Apr 21, 2011
• Journal: Applied Physics Letters
• Print ISSN: 0003-6951
• Electronic ISSN: 1077-3118
• Publisher: American Institute of Physics
• Peer Reviewed: Peer Reviewed
• Volume: 83
• Issue: 26
• Pages: 5434-5436
• DOI: https://doi.org/10.1063/1.1637717
• Keywords: Aluminium compounds, Gallium compounds, III-V semiconductors, Wide band gap semiconductors, X-ray diffraction, Semiconductor heterojunctions, Tilt boundaries, Twist boundaries, MOCVD coatings, Vapour phase epitaxial growth, Semiconductor growth.
• Public URL: https://durham-repository.worktribe.com/output/1611492