Fabrication Of ?001? Orientation Oxide Electrode And Ba_0.5Sr_0.5TiO₃ Thin Film By Pulsed Laser Depositon

Due to the splendid ferroelectric and dielectric properties,BaxSr1-xTiO3(BST)thin films have already been widely used in dynamic Random Access Device,Metal-Oxide-Semiconductor,Phase Shifter and other electric devices.In recent studies,conductive perovskite oxide materials used as electrode attract great attentions since the advantages of low cost,excellent thermal stability,well lattice matching with the functional materials.LaNiO3(LNO),a typical oxide conductive material with a consistent crystal lattice with other functional perovskite oxide materials,is widely used as electrode material to replace traditional metal electrodes such as Pt,Au.As a perovskite structure superconductive material,YBa2Cu3O7-?(YBCO)has been introduced as special electrodes in ferroelectric,ferromagnetic and dielectric functional thin films because of its unique performance below 77K.And some particular modulation phenomena,which emerge in the interface between superconducting/other perovskite thin films,have implications for applications.In the thesis,the influences of processing parameters of Pulsed laser deposition(PLD)on LNO thin films have been studied.C-oriented LNO thin films can be fabricated on Si(100)substrate with the optimum process gained above,which keeps a sheet resistant below 30?/?.YBCO thin films on LaAlO3(LAO)substrate have been made by PLD method under the best experimental conditions,which exhibit b-orientation.Room sheet temperature of YBCO film is about 70?/?.Ba0.5Sr0.5TiO3 thin films have been deposited on Si/LNO electrode obtained in the precious processes.Under the optimum substrate temperature and oxygen pressure,c-oriented LaNiO3/Ba0.5Sr0.5TiO3 films have been fabricated.The relations among Multi-layer structures,dielectric properties and experimental elements(substrate temperature and oxygen pressure)have been discussed.The sample's dielectric tunability is about 50%.At the same time,Ba0.5Sr0.5TiO3 thin films have also been deposited on LAO/YBCO substrates.The multi-layer structures of LAO/YBCO/BST films exhibit outstanding in-plan and out-plan orientations deposited in various experiment conditions,while the dielectric properties are not good as expected.Some probable reasons have been discussed,which are helpful in the deeper research.