Characterization of locally strained Ge1− x Sn x /Ge fine structures by synchrotron X-ray microdiffraction

We have investigated the formation of the locally strained Ge nanostructure with epitaxial Ge1−xSnx stressors and characterized the microscopic strain field in the Ge1−xSnx/Ge fine-heterostructures by synchrotron X-ray microdiffraction and finite element method (FEM) calculations. We achieved local epitaxial growth of Ge1−xSnx with Sn contents of 2.9% and 6.5%, sandwiching the 25 nm-wide Ge fine line structure. Microdiffraction measurements revealed that out-of-plane tensile strain induced in the Ge line effectively increased with decreasing Ge width and increasing Sn content of Ge1−xSnx stressors, which is in good agreement with FEM calculations. An out-of-plane tensile strain of 0.8% along the Ge[001] direction is induced in a 25 nm-wide Ge line, which corresponds to an in-plane uniaxial compressive strain of 1.4% in the Ge line sandwiched between Ge0.935Sn0.065 stressors.