Ferroelectric Thin Films Via Sol-Gel Processing of Singlesource Precursors

1993 ◽  
Vol 310 ◽  
Author(s):  
C.D. Chandler ◽  
M.J. Hampden-Smith ◽  
R.W. Schwartz
Keyword(s):  
Thin Films ◽  
Perovskite Phase ◽  
Ferroelectric Properties ◽  
Sol Gel ◽  
Dip Coating ◽  
Mixed Metal Oxide ◽  
Mixed Metal ◽  
Oxide Powders ◽  
Metal Organic ◽  
Gel Processing

AbstractThe use of single-source mixed metal-organic precursors specifically designed for the formation of crystalline perovskite phase mixed metal oxide powders has been investigated. Pyridine solutions of divalent metal α-hydroxycarboxylates of general empirical formula A(O2CCMe2OH)2 where A = Pb, Ca, Sr, Ba; Me = methyl, were designed to react with metal alkoxides, for example, Ti(O-i-Pr)4, with the elimination of two equivalents of alcohol to form species with fixed A:B stoichiometry of 1:1 according to the equation: A(O2CCMe2OH)2 + B(OR)4 → A(O2CCMe2O)2B(OR)2 + 2HOR. Hydrolysis of these compounds in pyridine produces clear solutions which on removal of the solvent in vacuo, yield yellow powders. These powders readily dissolve in ethanol to give solutions from which thin films can be formed either by dip-coating or spin coating. The crystallization behavior, composition and ferroelectric properties of these films is discussed. The crystallization of the films generally required substantially higher temperatures compared to powders obtained from the same precursor solutions.

Aerosol Routes to Perovskite Phase Mixed Metal Oxides

1993 ◽  
Vol 310 ◽  
Author(s):  
C.D. Chandler ◽  
Q. Powell ◽  
M.J. Hampden-Smith ◽  
T.T. Kodas
Keyword(s):  
Metal Oxide ◽  
Low Temperatures ◽  
Perovskite Phase ◽  
Mixed Metal Oxide ◽  
Single Source ◽  
Single Source Precursors ◽  
Mixed Metal ◽  
Oxide Powders ◽  
Metal Organic ◽  
Oxide Particles

AbstractSub-micron sized metal oxide particles were formed via aerosol decomposition using single-source mixed metal-organic precursors specifically designed to decompose at low temperatures. The advantage of these single-source precursors over mixtures of individual precursors is that each particle contains a fixed stoichiometry and molecular level homogeneity. Furthermore, the loss of volatile intermediates (such as PbO) may be avoided. Aerosol processing routes can produce uniform sub-micron sized powder that can be sintered at low temperatures for various thin film and membrane applications. The single-source precursors were prepared in pyridine by reaction of divalent metal α-hydroxycarboxylates of general empirical formula A(O2CCMe2OH)2 (where A = Pb, Ca, Sr, Ba; Me = methyl) with metal alkoxides (for example, Ti(O-i-Pr)4) with the elimination of two equivalents of alcohol. These species were then hydrolyzed in solution and yellow powders were isolated by removal of the pyridine solvent in vacuo. These powders were dissolved in water and used to prepare mixed metal oxide powders via spray pyrolysis. Phase-pure submicron-sized particles of PbTiO3 and BaTiO3 were produced at temperatures of 600-900 °C. The particles were hollow, ranged in size from 0.1 to 1 μm and consisted of 30-50 nm crystallites.

Dependence of Ferroelectric Properties of SBT Based Capacitors on the Electrode Material

1998 ◽  
Vol 541 ◽  
Author(s):  
S. Tirumala ◽  
S. O. Ryu ◽  
K. B. Lee ◽  
R. Vedula ◽  
S. B. Desu
Keyword(s):  
Thin Films ◽  
Electrode Material ◽  
Electrode Materials ◽  
Perovskite Phase ◽  
Ferroelectric Properties ◽  
Si Substrates ◽  
Non Volatile Memory ◽  
Metal Organic ◽  
Sputter Deposited ◽  
Memory Applications

AbstractThe effect of various electrode materials on the ferroelectric properties of SrBi2Ta2O9 (SBT) thin films has been investigated for non-volatile memory applications. Two sets of electrode structures, viz., Pt-Ir based and Pt-Rh based, were sputter deposited in-situ on Si substrates. SBT thin films were deposited on these electrodes using a metal-organic solution deposition technique followed by a post-deposition anneal at 750 °C in oxygen. Structural characterization revealed a polycrystalline nature with predominant perovskite phase in SBT thin films. Ferroelectric properties were studied in capacitor mode by depositing top electrodes, where the top electrode material is identical to that of the bottom electrode. Extensive analysis of the ferroelectric properties signify the important role played by the electrode material in establishing the device applicability is reported in this work.

Synthesis and Ferroelectric Properties of Sol–Gel Derived Intergrowth-Superlattice-Structured SrBi4Ti4O15-Bi4Ti3O12 Thin Films

2011 ◽  
Vol 197-198 ◽  
pp. 1781-1784
Author(s):  
Hua Wang ◽  
Jian Li ◽  
Ji Wen Xu ◽  
Ling Yang ◽  
Shang Ju Zhou
Keyword(s):  
Thin Films ◽  
Remanent Polarization ◽  
Annealing Temperature ◽  
Ferroelectric Properties ◽  
Sol Gel ◽  
Hysteresis Loops ◽  
Si Substrates ◽  
Gel Processing ◽  
Coercive Electric Field ◽  
Clockwise Hysteresis

Intergrowth-superlattice-structured SrBi4Ti4O15–Bi4Ti3O12(SBT–BIT) films prepared on p-Si substrates by sol-gel processing. Synthesized SBT–BIT films exhibit good ferroelectric properties. As the annealing temperature increases from 600°C to 700°C, the remanent polarization Prof SBT–BIT films increases, while the coercive electric field Ecdecreases. SBT–BIT films annealed at 700°C have a Prvalue of 18.9µC/cm2which is higher than that of SBT (16.8µC/cm2) and BIT (14.6µC/cm2), and have the lowest Ecof 142 kV/cm which is almost the same as that of SBT and BIT. The C-V curves of Ag/SBT-BIT/p-Si heterostructures show the clockwise hysteresis loops which reveal the memory effect due to the polarization. The memory window in C-V curve of Ag/SBT-BIT/p-Si is larger than that of Ag/SBT/p-Si heterostructure or Ag/BIT/p-Si heterostructure.

A Molecular Route to Dip-coated Transition Metal Nitride Thin Films.

2004 ◽  
Vol 848 ◽  
Author(s):  
Andrew W. Jackson ◽  
Andrew L. Hector
Keyword(s):  
Thin Films ◽  
Transition Metal ◽  
Spin Coating ◽  
Sol Gel ◽  
Particle Growth ◽  
Dip Coating ◽  
Stable Emulsion ◽  
Transition Metal Nitride ◽  
Sol Gel Synthesis ◽  
Gel Processing

ABSTRACTThere is an increasing interest in sol-gel synthesis of nitrides. The ability to deposit films of these materials by dip- or spin-coating will increase the range of applications in which they are viable and is an important step toward general sol-gel processing of nitride materials.With transition metals, the ammono based analogue of the well established alkoxy route to gels is inherently difficult to control. Due to the basicity of the system, the overwhelming tendency is of the starting materials to favour particle growth which results in a precipitate rather than a stable emulsion, unless both environment and synthetic pathway are carefully controlled. Hence reports to date of sol-gel routes to nitrides describe production of powders. We report work on a sol-gel route to titanium nitride with the ammonolysis of titanium amides controlled by temperature and chemical moderators, resulting in stable emulsions useful for dip-coating.

PVP-Mediated Crystallization of Perovskite Phase in the PMN-PT Thin Films Prepared by Sol-Gel Processing

2010 ◽  
Vol 93 (3) ◽  
pp. 686-691 ◽  
Author(s):  
Zehui H. Du ◽  
Tianshu S. Zhang ◽  
Minmin M. Zhu ◽  
Jan Ma
Keyword(s):  
Thin Films ◽  
Perovskite Phase ◽  
Sol Gel ◽  
Gel Processing

Ten Analyses Of Sol-Gel Derived And Sputtered PZT Thin Films

1990 ◽  
Vol 200 ◽  
Author(s):  
Cheng-Chen Hsueh ◽  
Martha L. MeCartney
Keyword(s):  
Thin Films ◽  
Ferroelectric Properties ◽  
Sol Gel ◽  
Rf Magnetron Sputtering ◽  
Pzt Thin Films ◽  
Ferroelectric Domains ◽  
Metal Organic ◽  
Organic Precursors ◽  
Acid Catalyzed ◽  
Sol Gel Films

ABSTRACTFerroelectric PZT thin films were prepared by sol-gel methods and RF magnetron sputtering. Sputtered PZT fast fired at 650° for 30 minutes showed microporosity. For the sol-gel route, solution precursors had a significant effect on the microstructure of the crystalline PZT films. PZT thin films derived from metal-organic precursors dissolved in n-propanol were observed to have large and microporous spherulitic grains on the order of 2 μm and phase separation in acetic acid-catalyzed films. In contrast, PZT precursors originated from alcohol exchanges with 2-methoxyethanols resulted in dense films with fine grains of ∼0.2 μm and clear evidence of ferroelectric domains. The dense sol-gel films possessed superior dielectric and ferroelectric properties.

Structural, Dielectric and Pyroelectric properties of Lanthanum modified Lead Titanate Thin Films

2004 ◽  
Vol 811 ◽  
Author(s):  
Sonalee Chopra ◽  
Seema Sharma ◽  
T.C. Goel ◽  
R.G. Mendiratta
Keyword(s):  
Thin Films ◽  
Lead Titanate ◽  
Mechanical Stability ◽  
Perovskite Phase ◽  
Ferroelectric Properties ◽  
Sol Gel ◽  
Microstructural Analysis ◽  
Pyroelectric Coefficient ◽  
Structural Investigations ◽  
Glass Substrates

ABSTRACTFerroelectric lead lanthanum titanate (Pb1−xLaxTi1−x/4O3) (PLTx) thin films (x=0.04,0.08 and 0.12) have been prepared by sol-gel spin coating process on ITO coated 7059 Corning glass substrates. Investigations have been made on the crystal structure, surface morphology, dielectric and ferroelectric properties of the thin films. For a better understanding of the crystallization mechanism, the structural investigations were carried out at various annealing temperatures (350°C, 450°C, 550°C and 650°C). Characterization of these films by X-ray diffraction shows that the films annealed at 650°C exhibit tetragonal structure with perovskite phase. Replacement of lanthanum in lead titanate results in reduction of tetragonal ratio (c/a), resulting in better mechanical stability. Microstructural analysis of the films are carried out by taking the Atomic Force Microscope (AFM) pictures. AFM images are characterized by slight surface roughness with a uniform crack free, densely packed structure. Dielectric, pyroelectric and ferroelectric studies carried out on these films have been reported. Dielectric constant and pyroelectric coefficient increase while Curie temperature decreases with increase in La content. The pyroelectric figures of merit of the films have also been calculated which suggest that 8% lanthanum is best suited material for pyroelectric detectors owing to its high pyroelectric coefficient (∼ 29nC/cm2 K), high voltage responsivity (∼420Vcm2/J), high detectivity (∼1.04×10−5Pa−1/2) and low variation of pyrocoefficient with temperature.

X-ray diffraction analysis for thin films of PbTiO3-La2/3TiO3 prepared by the sol-gel method

1994 ◽  
Vol 9 (8) ◽  
pp. 2133-2137 ◽  
Author(s):  
Hideki Yoshioka
Keyword(s):  
Thin Films ◽  
Perovskite Phase ◽  
Sol Gel ◽  
Diffraction Method ◽  
Dip Coating ◽  
X Ray Diffraction ◽  
X Ray ◽  
Coating Methods ◽  
Diffraction Patterns ◽  
System 1

Thin films in the system (1 - x) PbTiO3−xLa2/3TiO3 were prepared by the sol-gel and dip-coating methods. Phases deposited in the films and the lattice parameters as a function of the composition were investigated by the x-ray diffraction method. The solid solutions with a perovskite structure were formed as a single phase with x up to 0.9. For the composition of x = 1.0, metastable La-Ti-O perovskite phase with a small amount of the impurity phase, La2Ti2O7, was obtained. Simulation of x-ray diffraction patterns based on the defect structure model shows that the structure of the La-Ti-O perovskite phase includes randomly distributed cation vacancies at the A-site, namely (La2/3□1/3)TiO3.

Structure and Dielectric Properties of Zn Doped PST Thin Films Prepared by Sol-Gel Method

2007 ◽  
Vol 336-338 ◽  
pp. 283-286 ◽  
Author(s):  
Zan Zheng ◽  
Xiao Ting Li ◽  
Gao Rong Han ◽  
Wen Jian Weng ◽  
Pi Yi Du
Keyword(s):  
Thin Films ◽  
Dielectric Properties ◽  
Phase Structure ◽  
Perovskite Phase ◽  
Sol Gel ◽  
Dip Coating ◽  
In Doping ◽  
Ito Glass ◽  
Coating Method ◽  
Dip Coating Method

(PbySr1-y)ZnxTi1-xO3-x thin films were prepared on ITO/glass substrate by sol–gel process using dip-coating method. The phase structure, morphology, and dielectric properties of thin films were investigated by XRD, SEM and impedance analyzer, respectively. The perovskite phase structure was exhibited in the Zn-doped PST thin films. The formation ability of the thin films of the perovskite phase and its grain size decreased with the increase in doping Zn. The dielectric constant of the thin film was influenced by oxygen vacancies which could be controlled by Zn doping.

The role of excess Pb and PbO overpressure on the microstructural development in polycrystalline PZT thin films

1994 ◽  
Vol 52 ◽  
pp. 582-583
Author(s):  
M. J. Lefevre ◽  
D. B. Dimos ◽  
J. S. Speck
Keyword(s):  
Thin Films ◽  
Data Storage ◽  
Perovskite Phase ◽  
Ferroelectric Properties ◽  
Sol Gel ◽  
Pyrochlore Phase ◽  
Optical Data Storage ◽  
Optical Data ◽  
Microstructural Development

Ferroelectric thin films have recently received considerable attention because of their potential in a range of device applications including both volatile and non-volatile memories, optical data storage, and other electrooptic applications (e.g. waveguides, switches, and modulators). The Pb-based perovskites, such as Pb(Zr,Ti)O3, have many properties that make them attractive for such applications because of their high switchable remanant polarization. In addition, many applications require integration of the ferroelectric with semiconductors. In our work we are studying the crystallization sequence of PZT 40/60 (PbZr0.40Ti0.60O3) grown on platinized silicon substrates, with an overall structure given as PZT/Pt/Ti/SiO2Si. The Ti and Pt are sequentially evaporated onto the oxidized Si substrate. Alkoxide-derived films are spun onto these substrates to form a dry amorphous gel2. The crystallization of the sol-gel film proceeds upon heating to temperatures in the range of 400-700°C. Lead volatility is one of the critical issues in the crystallization of Pb-based perovskite thin films. We have carried out a systematic study on the role of a lead atmosphere in crystallization for PZT (40/60). When heat treated the film forms a transitory pyrochlore phase at intermediate temperatures before transforming to the perovskite phase. This non-ferroelectric pyrochlore phase may stabilize if lead stoichiometry is not maintained, leading to poor optical and ferroelectric properties in the thin films.

Sign in / Sign up

Export Citation Format

Share Document