SWITCHING AND FATIGUE CHARACTERISTICS OF (PB, LA)(ZR, TI)O3 THIN-FILMS BY METALORGANIC CHEMICAL-VAPOR-DEPOSITION

Lanthanum-modified lead zirconate titanate (PLZT) thin films (0.3 approximately 0.4 mum) have been prepared on Pt/SiO2/Si substrates at 650-degrees-C by the metal-organic chemical vapor deposition (MOCVD) method. The electrical properties of the films were examined as a function of lanthanum content. The relative dielectric constants increased as the La content increased to about 5 at%, and beyond this value, it became constant at 600. The remanent polarization and coercive field decreased from 22 to 1 muC/cm2 and from 90 to 20 kV/cm with increasing La content in the range of 0 approximately 11 at%, respectively. The leakage current density decreased considerably with the addition of La, and was 8 x 10(-9) A/cm2 at an applied voltage of 5 V. The switched charge densities of PLZT films showed almost no change up to switching cycles of 1 X 10(12) at a bipolar pulse of +/- 5 V.