X-ray reciprocal-space mapping of strain relaxation and tilting in linearly graded InAlAs buffers

Journal Article · Mon Apr 01 04:00:00 EST 1996 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.361410· OSTI ID:279727

Olsen, J A; Hu, E L ^[1]; Lee, S R; Fritz, I J; Howard, A J; Hammons, B E; Tsao, J Y ^[2]

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1. Department of Materials Engineering, University of California, Santa Barbara, Santa Barbara, California 93107 (United States)
2. Sandia National Laboratories, Albuquerque, New Mexico 87185-5800 (United States)

The extent of relaxation and orientation of linearly graded In{sub {ital x}}Al{sub 1-{ital x}}As ({ital x}=0.05{endash}0.25) buffers grown on GaAs were examined using a novel x-ray diffraction reciprocal-space mapping technique (kmap). Samples were grown at temperatures ranging from 370 to 550{degree}C. The fractional relaxation of the buffers grown between 470 and 550{degree}C was essentially identical (77{percent}) and symmetric in orthogonal {l_angle}110{r_angle} directions. These buffers are believed to be in equilibrium indicating that the incomplete relaxation is not a kinetic effect. The extent of relaxation was less than that expected for equilibrium relaxation in the absence of dislocation{endash}dislocation interactions indicating that such interactions must be considered to accurately predict the extent of relaxation. The saturation of the relaxation as a function of temperature indicates that at the grading rate used (8{percent} In/{mu}m or 0.69{percent} strain/{mu}m), we are not working in a growth regime where the relaxation is nucleation limited. In addition, all the buffers are slightly tilted with respect to the GaAs substrate about [1{bar 1}0] toward the [110] direction suggesting either a bias in the dislocation types in the boule-grown GaAs, or a bias in the way in which {alpha} and {beta} dislocations interact with unintentional substrate miscuts. {copyright} {ital 1996 American Institute of Physics.}

• Research Organization: Sandia National Laboratory
• DOE Contract Number: AC04-94AL85000
• OSTI ID: 279727
• Journal Information: Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 7 Vol. 79; ISSN JAPIAU; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM ARSENIDES
DISLOCATIONS
EPITAXIAL LAYERS
EPITAXY
GRADED BAND GAPS
INDIUM ARSENIDES
LAYERS
MAPPING
RELAXATION
STRAINS
TEMPERATURE DEPENDENCE
X-RAY DIFFRACTION