Ion-beam deposition of thin films of ferroelectric lead zirconate titanate (PZT)

Abstract

Lead zirconate titanate is a solid solution with nominal composition Pb(ZrxTi1−x)O3. Ferroelectric thin films of this material have been successfully deposited by a focused ion-beam sputtering technique in an O2 atmosphere. These films were characterized according to composition, crystal structure, and dielectric and ferroelectric properties. The effects of deposition temperature, heat treatment after deposition, and substrate and target material were investigated. The composition of the films was within 1 at.% of the composition of the multicomponent PZT target for substrate temperatures up to 200 °C. The Pb concentration decreased for substrate temperatures above 200 °C. Films deposited at substrate temperatures below 250 °C were microcrystalline. At 300 °C, the pyrochlore phase was obtained. Films with the ferroelectric perovskite structure were deposited above 400 °C, which is the lowest deposition temperature ever reported for this phase. O2 losses during postdeposition annealing resulted in a collapse of the perovskite structure. Ferroelectric hysteresis loop measurements indicated a saturation remanent polarization of 4.9 μC/cm2 and a coercive field of 25.2 kV/cm.