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Ferroelectric BaTiO3 is rarely used in monolithic Si devices due to the low quality of BaTiO3 films on Si, as polycrystallinity, degradation of bottom Pt electrodes, low polarization, and high roughness. Here, we overcome these limitations by using a buffer structure that combines yttria-stabilized zirconia, CeO2, and conducting LaNiO3. BaTiO3 films on the multilayered buffer, with total thickness of the buffer below 100 nm, are epitaxial, display remnant polarization of 6-10 μC/cm2, and have roughness of a few Å. These unprecedented properties pave the way to integrate ferroelectric BaTiO3 into Si platforms. [ABSTRACT FROM AUTHOR]

We have investigated the thermal stability of platinum electrodes on oxide substrates for oxide-based devices. We show that flat epitaxial Pt(111) bottom electrodes, deposited on SrTiO3(111) and Al2O3(0001) substrates, can be stable against dewetting up to usual oxide-deposition temperatures (Ts) by increasing Pt film thickness (tPt) and preferably using SrTiO3(111) rather than Al2O3(0001) substrates. Subsequently, high-quality epitaxial biferroic YMnO3/Pt/oxide-substrate heterostructures have been grown. A diagram of morphological and crystalline quality versus tPt and Ts is given for both YMnO3/Pt/SrTiO3(111) and YMnO3/Pt/Al2O3(0001) heterostructures. These results shall guideline the growth of other functional oxide thin films on Pt electrodes. [ABSTRACT FROM AUTHOR]