Stress-Induced Phase Formation of PZT 52/48 Thin Films

Abstract

In this work, tetragonal and rhombohedral phases in PZT 52/48 thin films were identified using XRD. The relative intensities of these phases were calculated. The presence of the rhombohedral phase may have implications for the piezoelectric properties, since the polar axis in rhombohedral crystals lies along the (111) body diagonal rather than the (001) axis for tetragonal crystals.The effects of stress on phase co-existence at the morphotropic phase boundary were also investigated. Two PZT52/48 films were grown under the compressive stresses of different magnitudes. For the film grown under smaller compressive stress, twophase co-existence was observed, but the film grown under larger compressive stress was observed to be rhombohedral dominant. The piezoelectric coefficient, d 33,f of the rhombohedral dominant film was less than that of the mixed-phase film. It is possible that a (001)/(100) oriented film of slightly tetragonal composition (e.g. 48/52) could have higher piezoelectric coefficients than a mixed-phase MPB film.

Development of residual stress in sol-gel derived Pb(Zr,Ti)O3 films: An experimental study

“…[2][3][4] The demand of the residual stress characterization arises from the requirement of stress-free MEMS structures since the residual film stress can cause the device bending, as shown by Zhang et al 5 The effects of residual stresses on the properties of thin films have been widely studied, for example, the effects of the residual stress on the ferroelectric and piezoelectric properties; [6][7][8] the effects of strain on the crystallographic orientation of the film when passing through the transition temperature; 9,10 the effects of applied stress on the ferroelectric properties; [11][12][13][14] and the effect of stress on the phase shift at the morphotropic phase boundary compositions. 15 The residual stress characterization of chemical solution deposition ͑CSD͒ derived PZT thick films was a subject of many investigations, first reported for CSD derived thick films by Yi and Sayer. 16 The intrinsic stress develops in CSD films during heat treatment as a result of solvent evaporation and leads to the shrinkage of the film.…”

Determination of residual stress in PZT films produced by laser ablation with X-ray diffraction and Raman spectroscopy

“…The film with composition Zr/Ti being 55/45 is under tensile stress might be due to the fact it is near of the morphotropic phase boundary, were the dielectric constant is higher and the value of stress increases and could change from compressive to tensile stress as observed. Further, films with higher Ti content exhibit low intensity of the rhombohedral phase when compared with those with low Ti content (PZT with ratio Zr/Ti 65/35 and 92/8) which allows to an increase of tensile stress [13].…”

Structural, Morphologic, and Ferroelectric Properties of PZT Films Deposited through Layer-by-Layer Reactive DC Magnetron Sputtering

“…The XRD patterns of the deposited films at 500, 550, and 600 • C substrate temperatures are shown in Figure 2. The best dielectric properties of Pb(Zr x Ti 1−x )O 3 were obtained at x value ~0.58 because the composition was near the morphotropic phase boundary [38]. The crystalline structure of PZT films depends on the substrate temperature when films are synthesized.…”