We report on fundamental studies of grazing incidence small angle X-ray scattering (GISAXS) on resistively switching SrTiO3 thin film metal-insulator-metal (MIM) devices. Different influence factors on the GISAXS scattering pattern, e.g., surface morphology and top electrode material, were evaluated by simulations and compared with subsequent measurements. Pt top electrodes cause a strong background scattering which covers any information from the underlying SrTiO3 layer. In order to reduce this undesired background scattering, the lighter elements Al and Ti have been used. In case of Ti top electrodes, we observed that a laterally formed structure occurs in the SrTiO3 prior to any electrical treatment, which is consistent with the forming-free properties of the MIM structures. For Al top electrodes, we could detect a significant influence of an electroforming step on the scattered intensity.