Sin2 ψ analysis in thin films using 2D detectors: Non-linearity due to set-up, stress state and microstructure

Abstract Two synchrotron set-ups have been used to carry out in situ strain measurements on systems constituted by Au films on polyimide substrates. These film/substrate composites have been submitted to either uniaxial or equibiaxial loadings. For the two configurations, an area detector (2D) was employed to extract the so-called e –sin 2 ψ curves. These latter are shown to be affected by geometrical effect unless equibiaxial loading is employed. Moreover, non-linearity of these curves can occur, even in the case of equibiaxial loading, when the film is thin (120 nm). This last phenomenon is explained by surface anisotropy.