Journal of Materials Research

Articles

Phase transformations in rapid thermal processed lead zirconate titanate

Ellen M. Griswolda1, L. Weavera1, M. Sayera2 and I.D. Caldera3

a1 Department of Materials and Metallurgical Engineering, Queen's University, Kingston, Ontario, Canada, K7L 3N6

a2 Department of Physics, Queen's University, Kingston, Ontario, Canada, K7L 3N6

a3 Telecom Microelectronics Centre, Northern Telecom Ltd., Nepean, Ontario, Canada

Abstract

The crystallization kinetics of the pyrochlore to perovskite phase transformation in lead zirconate titanate (PZT) thin films have been analyzed using rapid thermal processing (RTP). Sol-gel PZT thin films, fabricated on platinum electrodes, were annealed at 550 °C to 650 °C with hold times ranging from 1 s to 5 min. Glancing angle x-ray diffraction (XRD) was used for depth profiling to identify the location of phases in the films. Transmission electron microscopy (TEM) provided information on grain structure, nucleation, and growth. The phase information was correlated to the ferroelectric and dielectric properties. The perovskite phase nucleated in the pyrochlore phase throughout the film thickness, and at 650 °C the transformation was complete in 15 s. Fast growing (100) PZT nucleated at the platinum and consumed a small-grained matrix until a columnar structure was obtained. A ramp rate of 100 °C/s was sufficiently fast to prevent transformation during heating and allowed the direct application of an Avrami model for transformation kinetics. An activation energy of 610 kJ/mol was determined.

(Received January 13 1995)

(Accepted September 01 1995)

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