Comparative study of LNO, LSCO and LSMO as electrode layers for microelectronic capacitors by dynamic SIMS

Chemical solution-deposited multilayer systems of SrTiO3 (STO)/X/Pt/TiO2/SiO2/Si [where X=LaNiO3 (LNO), La0.5Sr0.5CoO3 (LSCO), La0.7Sr0.3MnO3 (LSMO)] were investigated by dynamic secondary-ion mass spectrometry (SIMS). The STO layer is intended to serve as a dielectric layer for a capacitor, the conducting layers ‘X’ are a buffer layer intended to eliminate fatigue effects, which usually occur at the Pt/STO interface. Depth profiles of the main components were obtained, revealing intense diffusion processes, which must have occurred during the deposition/crystallisation processes. Furthermore, Al impurities from the substrate, most probably originating from the Pt-sputter process, are preferentially found at the interfaces. Ti is found to diffuse from the (isolating) STO layer into the conductive ‘X’ oxide layers, where a region of constant concentration is observable in all three sample systems.