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Interplay between relaxation and Sn segregation during thermal annealing of GeSn strained layers.

Authors :
Comrie, C. M.
Mtshali, C. B.
Sechogela, P. T.
Santos, N. M.
van Stiphout, K.
Loo, R.
Vandervorst, W.
Vantomme, A.
Source :
Journal of Applied Physics. 2016, Vol. 120 Issue 14, p1-7. 7p. 1 Black and White Photograph, 1 Chart, 6 Graphs.
Publication Year :
2016

Abstract

The effect of thermal annealing on epitaxial GeSn (6.5% Sn) strained layers grown on Ge-buffered Si(100) wafers has been investigated using Rutherford backscattering spectrometry and X-ray diffraction to unambiguously determine the Sn substitutional content as well as the elastic strain in the layers. Vacuum annealing at temperatures below 400 °C for 20 min has no noticeable effect on the strain in the epitaxial layers. Once the temperature was raised above 400 °C, however, relaxation of the layer sets in and the GeSn layer has essentially completely relaxed following a 20 min anneal at 650 °C. Using Rutherford backscattering and channelling spectrometry to provide compositional information as a function of depth enables one to monitor the effect of the thermal anneal on the Sn distribution throughout the layer, and also to directly extract their substitutional fraction (i.e., their solubility in the lattice). The results obtained show that when the relaxation initially sets in both the Ge and the Sn remain firmly bound in substitutional lattice sites and it is only around 600 °C, and after substantial relaxation has taken place, that Sn is finally expelled from lattice sites and diffuses to the surface of the sample. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
00218979
Volume :
120
Issue :
14
Database :
Academic Search Index
Journal :
Journal of Applied Physics
Publication Type :
Academic Journal
Accession number :
118874030
Full Text :
https://doi.org/10.1063/1.4964692