Effect of annealing conditions on the leakage current characteristics of ferroelectric PZT thin films grown by sol-gel process

The microstructure and leakage current of lead zirconate titanate (PZT) thi n films were investigated to understand the mechanism of the leakage curren t and also to attempt to improve the leakage characteristics. The PZT thin films were prepared using a sol-gel process followed by crystallization in three different gas ambients, i.e. N-2, air and O-2 The three kinds of crys tallized samples show different microstructure and orientation. Electrical characterization of the PZT thin films including the permittivity, P-E hyst eresis, and the leakage current was carried out. It was found that the leak age current was affected not only by the microstructures of the films but a lso by the interface between the Pt electrode and the PZT film. Moreover, i t was found that more than one conduction mechanism is involved in the rang e of electric field used in the experiment. In the low electric field regio n the current conduction is ohmic and its mechanism is found to be electron hopping among electron traps. In the high field region the sample treated in N-2 shows Schottky emission, the sample treated in O-2 shows space charg e limited conduction, and the sample treated in air shows both Schottky and space charge conduction together. (C) 1999 Elsevier Science S.A. All right s reserved.