High-resolution x-ray reflectivity study of thin layered Pt-electrodes forintegrated ferroelectric devices

The structural interface properties of layered Pt/Ti/SiO2/Si electrodes hav e been investigated using high-resolution specular and diffuse x-ray reflec tivity under grazing angles. Currently this multilayer system represents a technological standard as bottom electrodes for ferroelectric thin-film app lications. For the electronic and ferroelectric properties of integrated de vices, the film-electrode interface is of crucial importance. We focused on Pt 1000 Angstrom /Ti 100 Angstrom /SiO2/Si electrodes prepared under annea ling conditions as employed in industrial processing, prior to the depositi on of ferroelectric films. The comparison between annealed and non-annealed electrodes clearly revealed strong interfacial effects due to interdiffusi on and oxidation of Ti, especially at the Pt-Ti interface. Migration of Ti into the Pt layer results in a shift of the critical angle due to the enclo sure of TiO2-x within the Pt layer. The heterogeneous distribution of TiO2- x, suggests a diffusion mechanism mainly along the Pt grain boundaries. At the SiO2 interface a relatively weakly oxidized Ti layer of 20 Angstrom rem ained, which is most probably correlated with the remaining adhesion to the substrate.