BST thin films grown in a multiwafer MOCVD reactor

(Ba0.7Sr0.3)TiO3 thin films with a typical thickness of 30 nm were deposited on platinized wafers in a planetary multi-wafer reactor combined with a liquid delivery system. As a direct consequence of the reactor design, we obtain high film uniformity over 6 inch wafers as well as efficiencies for the precursor incorporation as high as 40%. The composition and microstructure of the films were routinely investigated by X-ray diffraction and X-ray fluorescence analysis. Further details of the microstructure were investigated by scanning electron microscopy. The electrical properties are characterized in terms of permittivity, loss angle, leakage current and the response to DRAM pulses and characteristic values obtained for depositions at 625°C include a specific capacitance of 60 fF/μm2, a tanδ of 0.002 and leakage currents in the order of 10−10 A/cm2 at 1 V. The electrical properties are discussed in relation to the microstructure and stoichiometry within a wide range of parameters.