PREPARATION AND ELECTRICAL-PROPERTIES OF FERROELECTRIC (PB,LA)(ZR,TI)O-3 THIN-FILMS BY METALORGANIC CHEMICAL-VAPOR-DEPOSITION

Lanthanum-modified lead zirconate titanate (PLZT) thin films have been epitaxially grown on MgO (100) and Pt/SiO2/Si substrates at 650 degrees C by the metalorganic chemical vapor deposition (MOCVD) method. The properties of the films were examined as a function of lanthanum content. The films were of a single perovskite structure, and highly oriented to the c-axis of the tetragonal phase on a MgO (100) substrate. The films were transformed from tetragonal to nearly cubic as the La content increased. The relative dielectric constants increased, and the remanent polarization and coercive field decreased as the La content increased. The switching time and leakage current densities decreased with increasing La content. The fatigue of the films was relaxed as the La content increased. The fatigue of the PLZT films does not occur below 1.0 x 10(13) cycles at a working voltage of 3 V by means of the acceleration test.