PHASE-TRANSFORMATIONS IN RAPID THERMAL PROCESSED LEAD-ZIRCONATE-TITANATE

The crystallization kinetics of the pyrochlore to perovskite phase tra nsformation in lead zirconate titanate (PZT) thin films have been anal yzed using rapid thermal processing (RTP). Sol-gel PZT thin films, fab ricated on platinum electrodes, were annealed at 550 degrees C to 650 degrees 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 loc ation of phases in the films. Transmission electron microscopy (TEM) p rovided information on grain structure, nucleation, and growth. The ph ase information was correlated to the ferroelectric and dielectric pro perties. The perovskite phase nucleated in the pyrochlore phase throug hout the film thickness, and at 650 degrees C the transformation was c omplete in 15 a. Fast growing (100) PZT nucleated at the platinum and consumed a small-grained matrix until a columnar structure was obtaine d. A ramp rate of 100 degrees C/s was sufficiently fast to prevent tra nsformation during heating and allowed the direct application of an Av rami model for transformation kinetics. An activation energy of 610 kJ /mol was determined.