The effects of lattice deformations by application of uniaxial mechanical stress studied by means of the pertubed angular correlation technique in µm thin Si wafers. It was found that the application of stress along the three major lattice directions ⟨100⟩, ⟨110⟩ and ⟨111⟩ leads to a deformation of the lattice around the In probe and the devitation from the perfect cubic symmetry induces an electic field gradient at the In site. Further, evidence was found for a mismatch of the lattice parameter between the OIn implanted layer an the surronding pure Si substrate.