High resolution synchrotron X-ray studies of phase separation phenomena and the scaling law for the threading dislocation densities reduction in high quality AlGaN heterostructure

S. Lazarev, S. Bauer, K. Forghani, M. Barchuk, F. Scholz, T. Baumbach

Research output: Contribution to journalArticle

17 Citations (Scopus)

Abstract

High resolution X-ray coplanar (symmetric X-ray diffraction (SXRD) and asymmetric X-ray diffraction (ASXRD)) and non-coplanar diffraction (grazing incidence diffraction (GID)) have been used to investigate the quality of AlGaN epilayers with 20% Al content, grown on sapphire using SiNx interlayers. The measurement of reciprocal space maps (RSM) with higher orders of reflections of SXRD and ASXRD which is readily performed at the synchrotron with high resolution and intensity reveals the presence of several diffraction peaks originating from the occurrence of local differences in the lattice constants. Two distinguishable AlGaN phases having different crystalline parameters were clearly recognized from X-ray data and the corresponding densities of screw dislocations have been determined measured as function of the overgrowth thickness varying from 0.5 mm to 3.5 μm. The variation of the screw and edge type dislocation densities with the overgrowth thickness has been found to follow the scaling law h-n where h is the thickness of the buffer layer.

Original languageEnglish
Pages (from-to)51-56
Number of pages6
JournalJournal of Crystal Growth
Volume370
DOIs
Publication statusPublished - 1 May 2013
Externally publishedYes

Fingerprint

Scaling laws
Synchrotrons
Phase separation
scaling laws
Heterojunctions
synchrotrons
X ray diffraction
X rays
Diffraction
high resolution
diffraction
x rays
Screw dislocations
Aluminum Oxide
Epilayers
Buffer layers
Sapphire
Lattice constants
Crystalline materials
screw dislocations

Keywords

  • A1. Grazing incidence diffraction
  • A1. High resolution synchrotron X-ray diffraction
  • A1. Reciprocal space map
  • A1. Threading dislocation density
  • A1. Williamson-Hall plot
  • A2. AlGaN
  • A2. Metalorganic vapor phase epitaxy

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Materials Chemistry
  • Inorganic Chemistry

Cite this

High resolution synchrotron X-ray studies of phase separation phenomena and the scaling law for the threading dislocation densities reduction in high quality AlGaN heterostructure. / Lazarev, S.; Bauer, S.; Forghani, K.; Barchuk, M.; Scholz, F.; Baumbach, T.

In: Journal of Crystal Growth, Vol. 370, 01.05.2013, p. 51-56.

Research output: Contribution to journalArticle

@article{fa28dab25a0c4890b1e1f18b455f4aac,
title = "High resolution synchrotron X-ray studies of phase separation phenomena and the scaling law for the threading dislocation densities reduction in high quality AlGaN heterostructure",
abstract = "High resolution X-ray coplanar (symmetric X-ray diffraction (SXRD) and asymmetric X-ray diffraction (ASXRD)) and non-coplanar diffraction (grazing incidence diffraction (GID)) have been used to investigate the quality of AlGaN epilayers with 20{\%} Al content, grown on sapphire using SiNx interlayers. The measurement of reciprocal space maps (RSM) with higher orders of reflections of SXRD and ASXRD which is readily performed at the synchrotron with high resolution and intensity reveals the presence of several diffraction peaks originating from the occurrence of local differences in the lattice constants. Two distinguishable AlGaN phases having different crystalline parameters were clearly recognized from X-ray data and the corresponding densities of screw dislocations have been determined measured as function of the overgrowth thickness varying from 0.5 mm to 3.5 μm. The variation of the screw and edge type dislocation densities with the overgrowth thickness has been found to follow the scaling law h-n where h is the thickness of the buffer layer.",
keywords = "A1. Grazing incidence diffraction, A1. High resolution synchrotron X-ray diffraction, A1. Reciprocal space map, A1. Threading dislocation density, A1. Williamson-Hall plot, A2. AlGaN, A2. Metalorganic vapor phase epitaxy",
author = "S. Lazarev and S. Bauer and K. Forghani and M. Barchuk and F. Scholz and T. Baumbach",
year = "2013",
month = "5",
day = "1",
doi = "10.1016/j.jcrysgro.2012.07.033",
language = "English",
volume = "370",
pages = "51--56",
journal = "Journal of Crystal Growth",
issn = "0022-0248",
publisher = "Elsevier",

}

TY - JOUR

T1 - High resolution synchrotron X-ray studies of phase separation phenomena and the scaling law for the threading dislocation densities reduction in high quality AlGaN heterostructure

AU - Lazarev, S.

AU - Bauer, S.

AU - Forghani, K.

AU - Barchuk, M.

AU - Scholz, F.

AU - Baumbach, T.

PY - 2013/5/1

Y1 - 2013/5/1

N2 - High resolution X-ray coplanar (symmetric X-ray diffraction (SXRD) and asymmetric X-ray diffraction (ASXRD)) and non-coplanar diffraction (grazing incidence diffraction (GID)) have been used to investigate the quality of AlGaN epilayers with 20% Al content, grown on sapphire using SiNx interlayers. The measurement of reciprocal space maps (RSM) with higher orders of reflections of SXRD and ASXRD which is readily performed at the synchrotron with high resolution and intensity reveals the presence of several diffraction peaks originating from the occurrence of local differences in the lattice constants. Two distinguishable AlGaN phases having different crystalline parameters were clearly recognized from X-ray data and the corresponding densities of screw dislocations have been determined measured as function of the overgrowth thickness varying from 0.5 mm to 3.5 μm. The variation of the screw and edge type dislocation densities with the overgrowth thickness has been found to follow the scaling law h-n where h is the thickness of the buffer layer.

AB - High resolution X-ray coplanar (symmetric X-ray diffraction (SXRD) and asymmetric X-ray diffraction (ASXRD)) and non-coplanar diffraction (grazing incidence diffraction (GID)) have been used to investigate the quality of AlGaN epilayers with 20% Al content, grown on sapphire using SiNx interlayers. The measurement of reciprocal space maps (RSM) with higher orders of reflections of SXRD and ASXRD which is readily performed at the synchrotron with high resolution and intensity reveals the presence of several diffraction peaks originating from the occurrence of local differences in the lattice constants. Two distinguishable AlGaN phases having different crystalline parameters were clearly recognized from X-ray data and the corresponding densities of screw dislocations have been determined measured as function of the overgrowth thickness varying from 0.5 mm to 3.5 μm. The variation of the screw and edge type dislocation densities with the overgrowth thickness has been found to follow the scaling law h-n where h is the thickness of the buffer layer.

KW - A1. Grazing incidence diffraction

KW - A1. High resolution synchrotron X-ray diffraction

KW - A1. Reciprocal space map

KW - A1. Threading dislocation density

KW - A1. Williamson-Hall plot

KW - A2. AlGaN

KW - A2. Metalorganic vapor phase epitaxy

UR - http://www.scopus.com/inward/record.url?scp=84883172011&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84883172011&partnerID=8YFLogxK

U2 - 10.1016/j.jcrysgro.2012.07.033

DO - 10.1016/j.jcrysgro.2012.07.033

M3 - Article

AN - SCOPUS:84883172011

VL - 370

SP - 51

EP - 56

JO - Journal of Crystal Growth

JF - Journal of Crystal Growth

SN - 0022-0248

ER -