With the recent developments of the microelectronic industry, the intrinsic limits of the classical CMOS materials are being reached because of the strong miniaturization. Thus, the microelectronic industry is waiting for new solutions for combining, on the same substrate (silicon), different materials with various physical properties in the framework of integrating new functionalities on silicon. Research is now focusing on perovskite oxides because of the very wide range of properties they are offering (electronic, magnetic, etc.), but also on III-V semiconductors for the development of integrated photonic devices and on Ge for its electronic transport properties. However, combining these materials is challenging due to their strong chemical and crystallographic heterogeneity. Thus, this thesis focuses on the Ge/SrTiO3 system. The accommodation mode and growth mechanism have been studied by in situ, synchrotron-based, characterization methods like grazing incidence X-ray scattering and X-ray photoemission spectroscopy. The samples were prepared by molecular beam epitaxy. Transmission electron microscopy images complemented the study. The combination of these results have allowed for highlighting two specificities of the III-V or Ge/SrTiO3epitaxial systems. In a first chapter, the Volmer-Weber growth mode and a competition between (001)and (111)-oriented Ge islands is described. Epitaxial relationship between Ge and SrTiO3, chemical bonds at the interface and influence of adhesion and surface energies on the growth mode are described. In a second part, the specific accommodation mode of the Ge/SrTiO3 interface is studied. The development of a misfit dislocation network during the growth is experimentally observed and analyzed on the basis of a numerical model of the interface. This work provides state of the art understanding of the interface of weakly bonded epitaxial systems and opens interesting perspectives, especially related to the accommodation mode of semiconductors/oxides interfaces, for the monolithic integration of III-V or Ge on oxides/Si substrates.
