The atomic resolved displacements, stresses, strains, and the strain energy in laterally finite nanoscale Si(001) mesas, uncovered and covered with the lattice-mismatched Ge overlayer-induced stresses were investigated using atomistic simulations. Across the surface profile of the mesas and in the direction down to the substrate, the spatial variations of the stress were examined. Rapid changes from tensile in the interior of the Si mesa to compressive in the Ge overlayer in the hydrostatic stress and strain at the Ge/Si interface. Considerable inhomogeneity due to both finite geometry effects and the lattice-mismatched Ge overlayer-induced stresses were demonstrated by the atomic displacement fields.
Bibliographical noteFunding Information:
This work was supported by AFOSR under the MURI program on Nanoscience and the DURINT program of the National Nanotechnology Initiative. Simulations were performed using the high performance computing facilities at the University of Southern California.