Electrical properties of PZT thin films deposited on LSCO electrodes

Abstract

La0.5Sr0.5CoO3 (LSCO) thin films were deposited on Pt/Ti/SiO2/Si substrates by DC reactive sputtering at 450 degrees C and were annealed at temperatures ranging from 550 degrees C to 750 degrees C for 30 min in an O-2 ambient to improve the crystallinity of the LSCO film and to reduce its resisitivity. Pb(Zr0.48Ti0.52)O-3 (PZT) thin films were then deposited on the LSCO electrodes by using DC reactive sputtering at a substrate temperature of 550 OC. X-ray diffraction patterns indicate that the PZT films grown on the LSCO/Pt electrodes showed a (001) preferred orientation and had a uniform matrix of densely packed round grains. The PZT thin films showed a remanent polarization (2P(r)) of about 46 similar to 52 mu C/cm(2) and a coercive voltage of about 1 V. The leakage current density remained on the order of 10(-7)similar to 10(-8) A/cm(2) at applied voltage below 5 V. When LSCO was used as bottom electrode, an improvement in fatigue properties was obtained. After 10(10) cycles of switching at an applied voltage of 5 V, the thin film did not show any significant change in the polarization.