Growth and characterization of (Pb, La)TiO_3 films with and without a special buffer layer prepared by RF magnetron sputtering

摘要

The (Pb, La)TiO_3 (PLT) ferroelectric thin films with and without a special buffer layer of PbO_x have been deposited on Pt/Ti/SiO_2/Si(100) substrates by RF magnetron sputtering technique at room temperature. The microstructure and the surface morphology of the films annealed at 600℃ for 1 h have been investigated by X-ray diffraction (XRD) and atomic force microscope (AFM). The surface roughness of the PLT thin film with a special buffer layer was 4.45 nm (5 μm x 5 μm) in comparison to that of 31.6 nm (5 μm x 5 μm) of the PLT thin film without a special buffer layer. Ferroelectric properties such as polarization hysteresis loop (P-V loop) and capacitance-voltage curve (C-V curve) of the films were investigated. The remanent polarization (P_r) and the coercive field (E_c) are 21 μC/cm~2 and 130 kV/cm respectively, and the pyroelectric coefficient is 2.75 x 10~(-8) C/cm~2 K for the PLT film with a special buffer layer. The results indicate that the (Pb, La)TiO_3 ferroelectric thin films with excellent ferroelectric properties can be deposited by RF magnetron sputtering with a special buffer layer.