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Effects of Ge 2 Sb 2 Te 5 and GeTe oxidation on their phase-change properties were studied by optical measurements and Parallel Angle Resolved X-ray Photoelectron Spectroscopy (PARXPS). The influence of oxygen on the active material was depicted in order to explain variations of the phase-change properties. The surface analysis evidenced a two-steps oxidation involving the formation of germanium and antimony oxides then tellurium oxide. A smooth surface sputtering allowed physically distinguishing the different oxides on GeTe sample overlayer and gave information about oxidation mechanisms. A significant drift of crystallization temperatures and activation energies were observed after 12 months air exposure time that points out the influence of the phase-change materials oxidation on their active properties.

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HfO 2 and SrTiO 3 films were grown on silicon by liquid injection metal organic chemical vapour deposition. The microstructure and structure of the films were characterised by X-ray and electron diffraction, X-ray reflectometry, infrared spectroscopy, and microscopy techniques. In both cases, we emphasised the role of precursors in the resulting composition and microstructure of the films. Dense films of HfO 2 , either amorphous or crystalline depending on the deposition temperature, were synthesised using Hf(O t Bu) 2 (mmp) 2 precursor. Permittivity values of 14-19 were obtained, consistent with the monoclinic structure determined from X-ray diffraction. Optimised films exhibit breakdown field of6MVcm −1 and leakage current densities as low as 10 −8 Acm −2 at 1 V.Polycrystalline SrTiO 3 films were grown using either a mixture of precursors or a heterometallic precursor. The heterometallic precursor provides some advantages such as a lowering of the crystallisation temperature of the perovskite-type phase and a reduction of carbonate impurities at low temperatures. It also allows to keep the films composition constant over a wide temperature range (550-750 • C). The films are highly textured with [0 0 1] SrTiO 3 parallel to [0 0 1] Si . The permittivity depends strongly on the films thickness (ε r ∼ 30 for 10 nm and ε r ∼ 100 for 100 nm). An equivalent oxide thickness of 1.36 nm (for physical thickness of 15.0 nm) was obtained for optimised SrTiO 3 film, with a leakage current density of 10 −2 Acm −2 at 1 V.

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