  The structural interface properties of layered Pt/Ti/SiO2/Si electrodes have
been investigated using high-resolution specular and diffuse x-ray reflectivity
under grazing angles. Currently this multilayer system represents a
technological standard as bottom electrodes for ferroelectric thin film
applications. For the electronic and ferroelectric properties of integrated
devices, the film-electrode interface is of crucial importance. We focused on
Pt-100nm/Ti-10nm/SiO2/Si electrodes prepared under annealing conditions as
employed in industrial processing, prior to the deposition of ferroelectric
films. The comparison between annealed and non-annealed electrodes clearly
revealed strong interfacial effects due to interdiffusion and oxidation of Ti,
especially at the Pt-Ti interface. Migration of Ti into the Pt-layer results in
a clear shift of the critical angle due to enclosure of TiO(2-x) within the
Pt-layer. The heterogeneous distribution of TiO(2-x) suggests a diffusion
mechanism mainly along the Pt-grain boundaries. At the SiO2 interface a
relatively weakly oxidized, remaining Ti-layer of 20 Angstroem could be found,
which is most probably correlated with the remaining adhesion to the substrate.
