Metal-insulator-metal (MIM) structures with ultrahigh-k strontium titanate films (SrTiO3, STO) and Pt as the dielectric and electrode material, respectively, have been prepared by ALD. The MIM structures were prepared with near-stoichiometric and Sr-rich ([Sr]/([Sr]+[Ti]) = 0.54 and 0.63, respectively) with a thickness of 15 nm. The influence of the rapid thermal annealing step at 600 °C in flowing N2, required to crystallize the STO, on the crystalline microstructure of the Pt bottom electrode and of the STO films has been investigated. Transmission electron microscopy and electron diffraction analysis evidenced that the morphology of the Pt bottom electrode is influenced by thermal treatment. Locally, an epitaxial relation between the textured Pt and the STO film could be found. However, X-ray and electron diffraction analysis showed that the STO crystalline grains were mainly randomly oriented. Top view TEM analysis revealed that the near-stoichiometric STO thin films deposited on Pt have a crystallization behavior comparable to those deposited on Al2O3, with nano-crack formation at the grain boundaries and an average grain size of ~ 100 nm.