Strain relaxation in periodic arrays of Si SiGe quantum wires determined by coplanar high-resolution x-ray diffraction and grazing incidence diffraction

Elastic relaxation in dry-etched periodic wires fabricated from molecular b eam epitaxy grown Si/SiGe multilayers was studied by coplanar and grazing i ncidence (GID) high-resolution x-ray diffraction. The inhomogeneous strain distribution in the wires was calculated by the finite element method, whic h provided the input data for simulations of the scattered intensities usin g kinematical diffraction theory used for comparison with measured reciproc al space maps. A fabrication-induced layer covering the wire surfaces, modi fies the strain distribution. Using GID, the geometrical shape of the wires and their in-plane strain can be determined independently of each other.