Oriented Lead Zirconate Titanate thin Films: Characterization of Film Crystallization

Abstract

Through systematic variation of film processing temperature and time, we have characterized the pyrochlore to perovskite crystallization process of solution-derived PZT 20/80 thin films. The ≈3000 Å thick films were prepared by spin deposition using <100> single crystal MgO as the film substrate. By controlled rapid thermal processing, films at different stages in the perovskite crystallization process were prepared with the tetragonal PZT 20/80 phase being <100>/<001> oriented relative to the MgO surface. An activation energy for the conversion process of 326 kJ/mole was determined by use of an Arrhenius expression using rate constants found by application of the method of Avrami. The activation energy for formation of the PZT 20/80 perovskite phase of the solution-derived films compared favorably with that calculated from data by Kwok and Desu [1] for sputter-deposited 3500 Å thick PZT 55/45 films. The similarity in activation energies indicates that the energetics of the conversion process is not strongly dependent on the method used for film deposition.

Early Stages of Crystallization of Sol−Gel-Derived Lead Zirconate Titanate Thin Films

“…[18][19][20][21][22] Traditionally, these studies have been performed at moderate to high annealing temperatures. Voigt et al 18 studied the crystallization by rapid thermal annealing (RTA) of PZT(20/80) sol-gel thin films and reported an activation energy of 326 kJ/mol for the perovskite phase formation. Activation energies of 310 and 275 kJ/mol were obtained by Babushkin et al 19 and Griswold et al, 20 respectively, for sol-gel-derived PZT(53/47) films.…”

Simulation of the crystallization of thin films by rapid thermal processing

“…This is similar to that used by other authors. 9,10 The sizes of the domains do not enter the equations, they are a consequence of them. Given the assumptions on the growth rate, the interfaces between two phases are always circular and depend on the time delay between nucleations in neighboring grains.…”

“…This is consistent with experimental observations on the crystallization of PZT films on various substrates. 3,9,10 …”

“…Applications of this technology have been described elsewhere, [1][2][3][4][5][6] while some experimental 7 and theoretical 8 studies have suggested that rapid thermal annealing can influence or enhance the crystallization path within the film. Most recently, isothermal anneals 9 and stepped thermal processing 10 have been used to examine nucleated grain growth in lead zirconate titanate ͑PZT͒ films. Such growth occurs as part of the growth of a perovskite phase from a pyrochlore matrix.…”

Sol-gel deposition of PZT thin films on ceramic ZrO/sub 2/ substrates

“…MgO) greater than that of PZT. One effect of residual tensile film stresses is a preference for orientation of the polarization in the plane of the film [3,4]. In this work, PZT films of x = 0.55 (T c = 370°C) and x = 0.85 (T c = 460°C) were deposited by sol-gel on Y stabilized (6%) ceramic ZrO 2 substrates.…”