a1 Department of Materials Science and Engineering, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061
A two-step seeding process has been developed to lower the transformation temperature and modify the grain structure of ferroelectric lead zirconate titanate (PZT) thin films with high Zr/Ti ratio. Previous study has shown that nucleation is the rate-limiting step for the perovskite formation. Therefore, any process that enhances the kinetics of nucleation is likely to decrease the transformation temperature. In this process, a very thin (45 nm) seeding layer of PbTiO3, which has a low effective activation energy for perovskite formation, was used to provide nucleation sites needed for the low temperature perovskite formation. In this study, we have shown that the pyrochlore-to-perovskite phase transformation temperature of PbZrxTi1−xO3 films of high Zr/Ti ratio (e.g., x = 53/47) can be lowered by as much as 100 °C. The grain size of these films can also be substantially modified by this two-step approach.
(Received March 30 1992)
(Accepted October 08 1992)