Fine structure of AlN/AlGaN superlattice grown by pulsed atomic-layer epitaxy for dislocation filtering
- Department of Electrical Engineering, University of South Carolina, Columbia, South Carolina 29208 (United States)
We report the detailed structure analysis of our AlN/AlGaN superlattice (SL) grown by pulsed atomic-layer epitaxy (PALE) for dislocation filtering. Due to the nature of PALE, the AlGaN well material itself in the SL was found to be composed actually of an Al{sub x}Ga{sub 1-x}N/Al{sub y}Ga{sub 1-y}N short-period superlattice (SPSL), with the periodicity of 15.5 A ({approx_equal}6 monolayer), determined consistently from high-resolution x-ray diffraction and high-resolution transmission electron microscopy measurements. The SPSL nature of the AlGaN layers is believed to benefit from the AlN/AlGaN SL's coherent growth, which is important in exerting compressive strain for the thick upper n-AlGaN film, which serves to eliminate cracks. Direct evidence is presented which indicates that this SL can dramatically reduce the screw-type threading dislocation density.
- OSTI ID:
- 20706431
- Journal Information:
- Applied Physics Letters, Vol. 87, Issue 21; Other Information: DOI: 10.1063/1.2136424; (c) 2005 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0003-6951
- Country of Publication:
- United States
- Language:
- English
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