Patterning-induced strain relief in single lithographic SiGe nanostructures studied by nanobeam x-ray diffraction

Authors: Chrastina, D.; Vanacore, G.M.; Bollani, M.; Boye, P.; Schöder, S.; Burghammer, M.; Sordan, R.; Isella, G.; Zani, M.; Tagliaferri, A.

Source: Nanotechnology, Volume 23, Number 15, 20 April 2012 , pp. 155702-155711(10)

Publisher: IOP Publishing

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Abstract:

The continued downscaling in SiGe heterostructures is approaching the point at which lateral confinement leads to a uniaxial strain state, giving high enhancements of the charge carrier mobility. Investigation of the strain relaxation as induced by the patterning of a continuous SiGe layer is thus of scientific and technological importance. In the present work, the strain in single lithographically defined low-dimensional SiGe structures has been directly mapped via nanobeam x-ray diffraction. We found that the nanopatterning is able to induce an anisotropic strain relaxation, leading to a conversion of the strain state from biaxial to uniaxial. Its origin is fully compatible with a pure elastic deformation of the crystal lattice without involving plastic relaxation by injection of misfit dislocations.

Document Type: Research article

DOI: http://dx.doi.org/10.1088/0957-4484/23/15/155702

Publication date: 2012-04-20