Ferroelectric Thin Films by sol-gel Processing

1989 ◽  
Vol 152 ◽  
Author(s):  
S. L. Swartz ◽  
P. J. Melling ◽  
C. S. Grant

ABSTRACTThe sol-gel processing of ferroelectric thin films is being investigated at Battelle. The ferroelectric materials included in this study are PbTiO3, Pb(Zr, Ti)O3 (PZT), and KNbO3. The sol-gel processing and crystallization of these films on fused silica, silicon, alumina, and single crystal SrTiO3 substrates is described.Sol-gel derived PbTiO3 thin films crystallized into the expected tetragonal perovskite structure when heated to 500 C and above. However, the crystallization of sol-gel PZT (20/80) thin films was found to be substratedependent. The heat-treated PZT films were amorphous when deposited on silica and silicon substrates. Crystalline perovskite PZT films were produced on alumina substrates, and epitaxial PZT films were produced on single-crystal SrTiO3. Heat treatment of sol-gel KNbO3 films on silicon and alumina substrates resulted in the crystallization of a variety of non-perovskite phases, but epitaxial growth of KNbO3 was observed on single crystal SrTiO3.

2002 ◽  
Vol 16 (28n29) ◽  
pp. 4455-4459
Author(s):  
HAOSHUANG GU ◽  
WANQIANG CAO ◽  
JUNMIN XUE ◽  
JOHN WANG

A new system 0.1 BiFeO 3-0.9 SrBi 2 Nb 2 O 9 thin films have been successfully prepared by an ethanolamine-modified sol-gel technique. The precursor solution was synthesized from compounds, Bi(NO 3)3· 5H 2 O , Sr(NO 3)2, Fe(NO 3)3· 9H 2 O and Nb(OC 2 H 5)5 in solution ethylene glycol monomethyl ether. The thin films were deposited on Si single crystal by spinning coating, and heat-treated at temperatures ranging from 400°C to 700°C. Crystallization of thin films occurred at about 500 ~ 600°C and the films exhibit a pure phase of layered perovskite ferroelectric structure. The grain of films is well distributed and the average grain size of the film is about 100nm.


2012 ◽  
Vol 602-604 ◽  
pp. 1461-1464
Author(s):  
Hua Wang ◽  
Li Liu ◽  
Ji Wen Xu ◽  
Ling Yang ◽  
Shang Ju Zhou

[Pb0.95(La0.6Bi0.4)0.05][Zr0.53Ti0.47]O3 (PLBZT) ferroelectric thin films have been synthesized on ITO-coated glass by sol-gel processing. Effects of annealing temperature on structure and properties of PLBZT have been investigated. With the increase of annealing temperature from 500°C to 550°C, the remanent polarization Pr increase slightly to the maximum value of 25.4μC/cm2 due to the improvement in crystallization of PLBZT films. However, when the annealing temperature is more than 550°C, the pyrochlore phase appear and degrade the Pr of PLBZT thin films. The lowest leakage current density of 1.8×10-9 A/cm2 can be observed in PLBZT thin films when the annealing temperature is 550°C.


1996 ◽  
Vol 433 ◽  
Author(s):  
S. Trolier-Mckinstry ◽  
C. A. Randall ◽  
J. P. Maria ◽  
C. Theis ◽  
D. G. Schlom ◽  
...  

AbstractFerroelectric thin films typically differ from bulk ceramics in terms of both the average grain size and the degree of stress imposed on the film by the substrate. Studies on bulk ceramics have demonstrated that the number of domain variants within grains depends on the grain size for sizes <˜lμm. This can diminish the poling efficiency of the material. Since most thin films show primary grain sizes well below a micron, similar effects should be observed in films. In addition, since the perovskite ferroelectrics contain ferroelastic as well as ferroelectric domains, it seems clear that stress in thin films may markedly alter the degree to which domain walls contribute to the observed properties. In this paper, the relative importance of these factors are discussed for several types of ferroelectric thin films. Films have been prepared by pulsed laser deposition, magnetron sputtering, and by sol-gel processing. It has been found that epitaxial BaTiO3 films are ferroelectric at 77K down to thicknesses as low as ˜ 60nm. Data on the low and high field electrical properties are reported as a function of temperature, the film crystallinity, and film thickness for representative perovskite films.


2002 ◽  
Vol 748 ◽  
Author(s):  
R. S. Katiyar ◽  
A. Dixit ◽  
M. Jain ◽  
A. A. Savvinov ◽  
P. S. Dobal

ABSTRACTDuring a ferroelectric phase transition or domain rearrangement, ions or molecules in a ferroelectric material move in a highly cooperative manner from their initial lattice positions into the final positions they occupy and the collective response results into a “soft” lattice vibrational mode. Moreover, the structural changes are always accompanied by at least a few other changes in the normal mode behavior of the material. In the present work, Raman spectroscopy is conveniently employed to study such vibrational modes and other related phenomena in ferroelectric materials at the sub-microscale levels. We have investigated ferroelectric thin films of various lead and barium based perovskites prepared by sol-gel technique. The effect of processing conditions, A- and B- site substitutions, and size dependence on their Raman spectra were analyzed in terms of the structure-property correlations.


1995 ◽  
Vol 49 (3) ◽  
pp. 191-194 ◽  
Author(s):  
Liu Meidong ◽  
Lu Chunru ◽  
Wang Peiying ◽  
Rao Yunhua ◽  
Zeng Yike ◽  
...  

1992 ◽  
Vol 1 (1) ◽  
pp. 17-42 ◽  
Author(s):  
Yuhuan Xu ◽  
John D Mackenzie

1991 ◽  
Vol 230 ◽  
Author(s):  
Jeon-Kook Lee ◽  
Hyung-Jin Jung ◽  
Chong-Hee Kim

AbstractHigh quality lead titanate thin films were fabricated by spin coating on a silicon substrate. The resulting dried gel layers were uniform in thickness through 2 ' area, and polycrystalline perovskite structures developed almost crack free with a heat treatment above 500°C in films with thickness above 0.36μm.Metastable pyrochlore structures were observed in films with thickness of 0.16,μm when heat treated at 500 and 600 °C. But these structure did not appear in films with thickness of 0.36μm.The thickness dependencein crystal structure of films was studied by varing the substrate condition and analyzing the interface between the.film and. substrate. In native oxide films on silicon substrates, amorphous dried gel layers were heterogeneously nucleated. Metastable cubic pyrochlore structure could be crystallized in amorphous native oxide (cubic property in random network structure).


1994 ◽  
Vol 13 (24) ◽  
pp. 1804-1805 ◽  
Author(s):  
R. Sirera ◽  
M. L. Calzada ◽  
F. Carmona ◽  
B. Jim�nez

Author(s):  
TRINH BUI

PbZr0.4Ti0.6O3 (PZT) thin films have been conventionally fabricated on traditional silicon substrates with a platinum bottom electrode; however, as a consequence of unit cell mismatch, the films are difficult to form as an epitaxial-like growth. Hence, PZT films deposited on single-crystal niobium doped SrTiO3(111) substrates (Nb:STO) are promising to solve this issue thanks to the similar perovskite structure between PZT and STO. Essentially, Nb:STO material is a conductor, playing a part in both bottom electrode and epitaxial substrate. In this work, 200-nm-thick PZT films were successfully fabricated on Nb:STO substrates by a solution process. One obtained that PZT(111) peak started to appear on the Nb:STO substrate at a low annealing temperature of 450oC. Also, scanning electron microscopy observation shows smooth and homogeneous surface of PZT films on Nb:STO substrate with no grain boundary, which evidences for epitaxial-like growth of PZT thin films. Remnant polarization of 6 µC/cm2 and leakage current of 8×10-8 A were obtained at applied voltage of 5 V.


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