THE EFFECTS OF THE CATALYTIC NATURE OF CAPACITOR ELECTRODES ON THE DEGRADATION OF FERROELECTRIC PB(ZR,TI)O-3 THIN-FILMS DURING REDUCTIVE AMBIENT ANNEALING

The disappearance of ferroelectricity in Pb(ZT(0.52),Ti-0.48)O-3 (PZT) thin-film capacitors, which is caused by heat treatment in a reductiv e ambience, is investigated. Pare PZT films are not damaged by anneali ng in a hydrogen-containing atmosphere (H-2 annealing) up to 400 degre es C, whereas a PZT capacitor with Pt electrodes loses its ferroelectr icity during annealing at less than 300 degrees C. We have found that the degradation of ferroelectricity depends upon the metal used for th e top electrode of the PZT capacitor. The increased degradation in the case of a PZT capacitor with Pt electrodes can be explained by a cata lytic reaction on the Pt surface. We have made the ferroelectricity of a Pt/PZT/Pt capacitor retained even after the H-2 annealing at 300 de grees C, or above, simply by oxidizing it before the H-2 annealing. (C ) 1997 American Institute of Physics.