Micro structure and ferroelectric properties of BaTiO_3 films on LaNiO_3 buffer layers by rf sputtering

摘要

We have fabricated LaNiO_3 and BaTiO_3 films using the rf sputtering method. The LaNiO_3 were deposited on Si substrates, demonstrating a (100) highly oriented structure and nanocrystalline characteristic with a grain size of 30 nm. The BaTiO_3 thin films were deposited on the LaNiO_3 buffer layers, and have exhibited a (100) texture with a thickness of 400 nm. A smooth interface is obtained between the LaNiO_3 bottom electrode and the BaTiO_3 film from cross-section observations by scanning electron microscopy. The bi-layer films show a dense and column microstructure with a grain size of 60 nm. Ferroelectric characterizations have been obtained for the BaTiO_3 films. The remnant polarization and coercive field are 2.1 μC/cm~2 and 45 kV/cm, respectively. The leak current measurements have shown a good insulating property.