Effects of crystalline quality and electrode material on fatigue in Pb(Zr,Ti)O3 thin film capacitors

Pb(Zr0.52Ti0.48)O3(PZT)/Y 1Ba2Cu3Ox(YBCO) heterostructures have been grown by pulsed laser deposition, in which PZT films were epitaxial, highly oriented, or polycrystalline. These PZT films were obtained by varying the deposition temperature from 550 to 760°C or by using various substrates such as SrTiO3(100), MgO(100), and r-plane sapphire. PZT films with Pt top electrodes exhibited large fatigue with 35%-50% loss of the remanent polarization after 109 cycles, depending on the crystalline quality. Polycrystalline films showed better fatigue resistance than epitaxial or highly oriented films. However, PZT films with both top and bottom YBCO electrodes had significantly improved fatigue resistance for both epitaxial and polycrystalline films. Electrode material seems to be a more important parameter in fatigue than the crystalline quality of the PZT films.