SrBi2Nb2O9 ferroelectric thin films deposited by pulsed laser deposition on textured and epitaxied platinum electrodes

SBN thin films have been deposited by pulsed laser deposition on polycrystalline Pt/TiI/SiO2/Si (Pt/Si) substrates and on Pt epitaxied on (100)MgO, (100) or (110)SrTiO3 single crystals. On Pt/Si substrates. SBN polycrystalline films were obtained in situ at 70degrees'C. X-ray diffraction (XRD) patterns indicate that these films exhibit some (001) preferential orientation and also reveal some formation of secondary phases which can be due to reaction between film and substrate as suggested by Secondary Ions Mass Spectrometry (SIMS) results. Alternatively, in view of ferroelectric investigations, SBN films were deposited at lower temperature (typically 400degreesC) and then annealed at 750degreesC under air in order to allow better grain growth and to overcome this (001) preferential orientation that is deleterious for ferroelectric performances in such a structure. On single crystalline substrates, Pt bottom electrodes were deposited by d.c. sputtering at similar to450degreesC. Their epitaxial growth was confirmed by Electron Channeling Pattern (ECP) and XRD in theta-2theta and phi-scan modes. SBN films grown on (100)Pt/(100)SrTiO3 and (100)Pt/(100)MgO are (001) oriented and in-plane rotated by 45degrees with respect to die substrate while SBN films grown on (110)Pt/(110)SrTiO3 are (116) oriented as shown by theta-2theta and phi-scans. SIMS also reveals interdiffusion. Finally, the morphologies of these various films (Scanning Electron Microscopy) have been compared.