Closely spaced SiGe barns as stressor structures for strain-enhancement in silicon

We present tensile and compressive strains realized within the same Si capping layer on an array of SiGe islands grown on pit-patterned (001) Si substrates. The strain distributions are obtained from synchrotron X-ray diffraction studies in combination with three-dimensional finite element calculations and simulations of the diffracted intensities. For barn-shaped islands grown at 720 °C with average Ge contents of 30%, the Si cap layer is misfit- and threading-dislocation free and exhibits compressive strains as high as 0.8% in positions between the islands and tensile strains of up to 1% on top of the islands.