Enhanced ferroelectric properties of multilayer SBT-BTN thin films for NVRAM applications

摘要

Ferroelectric SrBi2Ta2O9 - (Bi4Ti3)(1-x)NbxO12 (SBT-BTN) multilayer thin films with various stacking periodicity have been synthesized on Ir/Ti/SiO2/Si substrates by metal organic chemical vapor deposition technique (MOCVD). Tributylbismuth [Bi(C4H9)(3)], strontium-bis[tantal(pentane-ethoxy)(2-methoxyethoxide)] [Sr[Ta(OEt)(5)(OC2H4OMe)](2)], titanium bis(isopropoxy)bis(1-methoxy-2-methyl-2-propoxide) [Ti(OiPr)(2)(mmp)(2)] and niobium-ethoxide [Nb(OC2H5)(5)] were selected as precursors. X-ray diffraction patterns show that the multilayer films annealed at 800 degrees C consisted of a fully formed perovskite phase with polycrystalline structure. The remanent polarization (2P(r)) and coercive field strength (E-c) were 16.2C/cm(2) and 230kV/cm, respectively, values which are much higher compared to pure SBT film (2P(r) = 6.4C/cm(2), E-c = 154kV/cm).