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
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
Publication date: 2012-04-20