X-ray diffraction study of the composition and strain fields in buried SiGe islands

Nina Hrauda, J. J. Zhang, M. Stoffel, J. Stangl, G. Bauer, A. Rehman-Khan, V. Holý, O. G. Schmidt, V. Jovanovic, L. K. Nanver

Research output: Contribution to journalArticleAcademicpeer-review

5 Citations (Scopus)

Abstract

We report on studies of strain and composition of two-dimensionally ordered SiGe islands grown by molecular beam epitaxy using high resolution x-ray diffraction. To ensure a small size distribution of the islands, pit-patterned 4″ (001) Si wafers were used as substrates. The Si wafers were patterned by optical lithography and reactive ion etching. The pits for island growth are ordered in regular 2D arrays with periods ranging from 500 to 1000 nm along two orthogonal 〈110〉 directions. After the growth of a Si buffer layer, 5 to 9 monolayers of Ge are deposited, leading to the formation of islands with either dome- or barn shape, depending on the number of monolayers deposited. The Si capping of the islands is performed at low temperatures (300°C) to avoid intermixing and thus strain relaxation. Information on the surface morphology obtained by atomic force microscopy (AFM) was used to set up models for three-dimensional Finite Element Method (FEM) simulations of the islands including the patterned Si substrate. In the model, special attention was given to the non uniform distribution of the Ge content within the islands. The FEM results served as an input for calculating the diffracted x-ray intensities using kinematical scattering theory. Reciprocal space maps around the vicinity of symmetric (004) and asymmetric (113) and (224) Bragg peaks were recorded in coplanar geometry. Simulating different germanium gradients leads to altered scattered intensity distribution and consequently information on this quantity is obtained for both dome- and barn-shaped islands as well as on the strain fields.

Original languageEnglish
Pages (from-to)41-46
Number of pages6
JournalEuropean Physical Journal: Special Topics
Volume167
Issue number1
DOIs
Publication statusPublished - 9 Apr 2009
Externally publishedYes

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Domes
Monolayers
Germanium
Finite element method
Strain relaxation
X ray diffraction
X rays
Reactive ion etching
Photolithography
Substrates
Buffer layers
Chemical analysis
diffraction
Molecular beam epitaxy
Surface morphology
Atomic force microscopy
x rays
Diffraction
Scattering
Geometry

Cite this

Hrauda, Nina ; Zhang, J. J. ; Stoffel, M. ; Stangl, J. ; Bauer, G. ; Rehman-Khan, A. ; Holý, V. ; Schmidt, O. G. ; Jovanovic, V. ; Nanver, L. K. / X-ray diffraction study of the composition and strain fields in buried SiGe islands. In: European Physical Journal: Special Topics. 2009 ; Vol. 167, No. 1. pp. 41-46.
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Hrauda, N, Zhang, JJ, Stoffel, M, Stangl, J, Bauer, G, Rehman-Khan, A, Holý, V, Schmidt, OG, Jovanovic, V & Nanver, LK 2009, 'X-ray diffraction study of the composition and strain fields in buried SiGe islands' European Physical Journal: Special Topics, vol. 167, no. 1, pp. 41-46. https://doi.org/10.1140/epjst/e2009-00934-7

X-ray diffraction study of the composition and strain fields in buried SiGe islands. / Hrauda, Nina; Zhang, J. J.; Stoffel, M.; Stangl, J.; Bauer, G.; Rehman-Khan, A.; Holý, V.; Schmidt, O. G.; Jovanovic, V.; Nanver, L. K.

In: European Physical Journal: Special Topics, Vol. 167, No. 1, 09.04.2009, p. 41-46.

Research output: Contribution to journalArticleAcademicpeer-review

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T1 - X-ray diffraction study of the composition and strain fields in buried SiGe islands

AU - Hrauda, Nina

AU - Zhang, J. J.

AU - Stoffel, M.

AU - Stangl, J.

AU - Bauer, G.

AU - Rehman-Khan, A.

AU - Holý, V.

AU - Schmidt, O. G.

AU - Jovanovic, V.

AU - Nanver, L. K.

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