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Tan, P. H. ; Bougeard, Dominique ; Abstreiter, Gerhard ; Brunner, K.

Depth profile of strain and composition in Si/Ge dot multilayers by microscopic phonon Raman spectroscopy

Article

Tan, P. H., Bougeard, Dominique, Abstreiter, Gerhard and Brunner, K. (2005) Depth profile of strain and composition in Si/Ge dot multilayers by microscopic phonon Raman spectroscopy. J. Appl. Phys. 98, p. 113517.

DOI to cite this document: 10.5283/epub.27792


Abstract

We characterized strain and Ge content depending on depth in a self-assembled Si/Ge dot multilayer by scanning a microscopic Raman probe at a (110) cleavage plane. The multilayer structure was deposited by molecular-beam epitaxy on a (001) Si substrate and consisted of 80 periods, each of them composed by 25 nm Si spacers and 8 monolayer Ge forming laterally and vertically uncorrelated islands ...

We characterized strain and Ge content depending on depth in a self-assembled Si/Ge dot multilayer by scanning a microscopic Raman probe at a (110) cleavage plane. The multilayer structure was deposited by molecular-beam epitaxy on a (001) Si substrate and consisted of 80 periods, each of them composed by 25 nm Si spacers and 8 monolayer Ge forming laterally and vertically uncorrelated islands with a height of 2 nm and a lateral diameter of about 20 nm. An average biaxial strain of -3.5% within the core regions of islands is determined from the splitting of longitudinal and transversal optical Ge-Ge phonon modes observed in polarized Raman measurements. The absolute mode frequencies further enable analysis of a Ge content of 0.82. The analyzed strain and composition of islands are nearly independent from depths below the sample surface. This indicates well-controlled deposition parameters and negligible intermixing during deposition of subsequent layers. These Raman results are in agreement with x-ray diffraction data. Small, local Raman frequency shifts were observed and discussed with respect to partial elastic strain relaxation of the multilayer stack after cleavage, undefined Raman-scattering geometries at the sample edge, and local heating by the laser probe.



Involved Institutions


Details

Item typeArticle
Journal or Publication TitleJ. Appl. Phys.
PublisherAmerican Institute of Physics (AIP)
Volume98
Page Rangep. 113517
Date2005
Date of publication05 Mar 2013 07:24
InstitutionsPhysics > Institute of Experimental and Applied Physics > Chair Professor Huber > Group Dominique Bougeard
Identification Number
ValueType
10.1063/1.2140078DOI
Dewey Decimal Classification500 Science > 530 Physics
StatusPublished
RefereedYes, this version has been refereed
Created at the University of RegensburgNo
URN of the UB Regensburgurn:nbn:de:bvb:355-epub-277920
Item ID27792

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