Sol-Gel Derived Pb(Zn1/3Nb2/3)O3-PbTiO3 Thin Films

1997 ◽  
Vol 493 ◽  
Author(s):  
G. Teowee ◽  
K. C. McCarthy ◽  
F. S. McCarthy ◽  
D. G. Davis ◽  
J. T. Dawley ◽  
...  
Keyword(s):  
Thin Films ◽  
Dielectric Constant ◽  
Firing Temperature ◽  
Remanent Polarization ◽  
Single Phase ◽  
Perovskite Phase ◽  
Sol Gel ◽  
Pyrochlore Phase ◽  
Dissipation Factor ◽  
Pt Films

ABSTRACTA series of sol-gel derived PB(Zn1/3Nb2/3)O3-PbTiO3 (PZN-PT) films, with various PbTiO3 contents, have been prepared on platinized Si wafers. The (l-x)PZN - xPT films fired to 700C became single phase perovskite for x > 0.7. In the PZN-0.1PT films, the films still contain pyrochlore phase at a firing temperature of 850C; the perovskite phase appeared at a firing temperature of 800C. The dielectric constant increased with increasing PT content, with a peak in dielectric constant at x = 0.8. PZN-PT films with x = 0.8 exhibited dielectric constant, dissipation factor, remanent polarization and coercive field values of 600, 0.10, 6 and 45 kV/cm respectively.

Studies on the Preparation and Characterization of Ferroelectric PLZT Film Capacitors

2011 ◽  
Vol 110-116 ◽  
pp. 5483-5486
Author(s):  
Li Liu ◽  
Hua Wang ◽  
Ji Wen Xu ◽  
Ming Fang Ren ◽  
Ling Yang
Keyword(s):  
Thin Films ◽  
Remanent Polarization ◽  
Perovskite Phase ◽  
Sol Gel ◽  
Pyrochlore Phase ◽  
X Ray Diffraction ◽  
Glass Substrates ◽  
Plzt Thin Films ◽  
Coercive Electric Field

(Pb0.92La0.08)(Zr0.65Ti0.35) O3(PLZT) thin films were fabricated on indium-doped tin oxide (ITO)-coated glass substrates to create transparent capacitor by the sol-gel method following annealing process. X-ray diffraction analysis shows that the PLZT thin films are polycrystalline with a single perovskite phase at 650°C. The ferroelectric, electrical and optical properties of these films were investigated in detail as a function of annealing temperature. Measurements with the PLZT films annealed at 650°C yielded the following: relative permittivity≈775 and dielectric loss (tanδ) ≈0.054, leakage current of 7.1× 10-9A, and remanent polarization of 38 μC/cm2 and the coercive electric field of 55 kV/cm and transparency of 88%. The pure perovskite films exhibit better properties than those films which have some fraction of pyrochlore phase.

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.

Effects of Annealing Temperature on Structure and Properties of PLBZT Ferroelectric Thin Films Synthesized by Sol-Gel Processing

2012 ◽  
Vol 602-604 ◽  
pp. 1461-1464
Author(s):  
Hua Wang ◽  
Li Liu ◽  
Ji Wen Xu ◽  
Ling Yang ◽  
Shang Ju Zhou
Keyword(s):  
Thin Films ◽  
Remanent Polarization ◽  
Annealing Temperature ◽  
Sol Gel ◽  
Pyrochlore Phase ◽  
Ferroelectric Thin Films ◽  
Structure And Properties ◽  
Maximum Value ◽  
Processing Effects ◽  
Gel Processing

[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.

Electrical Characterization of Sol-Gel Derived PZT Films

1991 ◽  
Vol 243 ◽  
Author(s):  
G. Teowee ◽  
J.M. Boulton ◽  
S.C. Lee ◽  
D.R. Uhlmann
Keyword(s):  
Dielectric Constant ◽  
Low Temperatures ◽  
Lead Acetate ◽  
Single Phase ◽  
Sol Gel ◽  
Pyrochlore Phase ◽  
Electrical Characterization ◽  
Aging Rate ◽  
Pzt Films

AbstractSol-gel derived PZT films were successfully prepared from precursor solutions based on lead acetate and Zr/Ti alkoxides. A pyrochlore phase was observed in films fired at low temperatures, while single-phase perovskite films were obtained at temperatures above 725C. The dielectric constant increased to above 1000 when there was a higher proportion of perovskite than pyrochlore. The films were essentially fatigue-free up to 108 cycles and exhibited a low aging rate of 5.7% / decade-sec.

scholarly journals Robust ferroelectricity enhancement of PZT thin films by a homogeneous seed layer

2021 ◽  
Author(s):  
jie jiang ◽  
Lei Liu ◽  
Kuo Ouyang ◽  
Zhouyu Chen ◽  
Shengtao Mo ◽  
...  
Keyword(s):  
Thin Films ◽  
Electrical Properties ◽  
Remanent Polarization ◽  
Perovskite Phase ◽  
Ferroelectric Properties ◽  
Sol Gel ◽  
Pzt Thin Films ◽  
Large Dielectric Constant ◽  
Sol Gel Process ◽  
A New Technique

Abstract With its excellent ferroelectric properties such as large dielectric constant and large remanent polarization, PZT thin films are extensively used in micro-sensors and other devices. In this study, the sol-gel process was used to fabricate Pb(Zr0.52Ti0.48)O3 thin films with Pb(ZrxTi1−x)O3 seed islands. The experimental consequences demonstrate that all the Pb(Zr0.52Ti0.48)O3 thin films with Pb(ZrxTi1−x)O3 seeds show pure perovskite phase with no other impurity phases, and the electrical properties of Pb(Zr0.52Ti0.48)O3 thin films modified by Pb(ZrxTi1−x)O3 seed islands with different Zr/Ti ratios are improved, such as remanent polarization increased, dielectric properties increased, coercive electric field decreased, leakage current density decreased, etc. In particular, the electrical properties of the Pb(Zr0.52Ti0.48)O3 thin films with Pb(ZrxTi1−x)O3 seed islands are the most optimal when the x is 0.52. This paper provides a new technique for optimizing the electrical properties of PZT thin films, which is of great significance for breaking through the bottleneck of the development of ferroelectric memory.

scholarly journals Solution Chemistry Optimization of Sol-Gel Processed Pzt Thin Films

1993 ◽  
Vol 310 ◽  
Author(s):  
Steven J. Lockwood ◽  
R. W. Schwartz ◽  
B. A. Tuitle ◽  
E. V. Thomas
Keyword(s):  
Thin Films ◽  
Acetic Acid ◽  
Remanent Polarization ◽  
Ferroelectric Properties ◽  
Sol Gel ◽  
Pyrochlore Phase ◽  
Solution Chemistry ◽  
Water Volume ◽  
Original Solution ◽  
Pzt Thin Films

AbstractWe have optimized the ferroelectric properties and microstructural characteristics of sol-gel PZT thin films used in a CMOS-integrated, 256 bit ferroelectric non-volatile memory. The sol-gel process utilized in our work involved the reaction of Zr n-butoxide, Ti isopropoxide, and Pb (IV) acetate in a methanol/acetic acid solvent system. A 10-factor screening experiment identified solution concentration, acetic acid addition, and water volume as the solution chemistry factors having the most significant effects on the remanent polarization, coercive field, ferroelectric loop quality, and microstruntural quality. The optimal values for these factors were determined by runnig a 3-factor uniform shell design, modelling the responses, and testing the models at the predicted optimal conditions. The optimized solution chemistry generated 3-layer, 300-400 nm thick films on RuO2 coated silicon substrates with coercive fields of less than 25 kV/cm (a 40-50 % improvement over the original solution chemistry), a remanent polarization of 25-30 μC/cm, and a reduction in the pyrochlore phase content below observable levels.

Ferroelectric thin films with complex composition of PNN–PZN–PMN–PZ–PT and excess NiO

2008 ◽  
Vol 23 (2) ◽  
pp. 536-542 ◽  
Author(s):  
Phoi Chin Goh ◽  
Kui Yao ◽  
Zhong Chen
Keyword(s):  
Thin Films ◽  
Electrical Properties ◽  
Perovskite Phase ◽  
Sol Gel ◽  
Pyrochlore Phase ◽  
Oxide System ◽  
Ferroelectric Thin Films ◽  
Ionic Radii ◽  
Pt Complex ◽  
The Stability

Ferroelectric thin films of the 0.1Pb(Ni1/3Nb2/3)O3–0.35Pb(Zn1/3Nb2/3)O3–0.15Pb (Mg1/3Nb2/3)O3–0.1PbZrO3–0.3PbTiO3 (PNN–PZN–PMN–PZ–PT) complex oxide system were prepared on Pt/Ti/SiO2/Si substrates using a polymer-modified sol-gel method followed by a rapid thermal annealing (RTA) process. It was found that the addition of excess NiO is effective in stabilizing the perovskite phase while suppressing the pyrochlore phase. The crystalline structure and morphology of the films with different amounts of access NiO were studied with x-ray diffraction (XRD) and field-emission scanning electron microscopy (FE-SEM), respectively. The electrical properties, including dielectric, ferroelectric, and piezoelectric, showed a significant improvement with excess NiO. The film sample with 3 mol% of excess NiO exhibited optimized electrical properties. Different parameters, including tolerance factors on the basis of ionic radii, electronegativity differences between cations and anions, and oxygen bond valences, were applied to analyze the stability of the perovskite phase with different amount of excess NiO. Analysis results indicated that only the bond-valence theory could explain the effect of excess NiO on the stability of the perovskite phase under the assumption that the excess Ni2+ entered the A sites of the perovskite structure.

Fabrication and Characterization of Lead Silicate Doped PZT Thin Films

2002 ◽  
Vol 748 ◽  
Author(s):  
Junichi Karasawa ◽  
Yasuaki Hamada ◽  
Koji Ohashi ◽  
Takeshi Kijima ◽  
Eiji Natori ◽  
...  
Keyword(s):  
Thin Films ◽  
Perovskite Phase ◽  
Sol Gel ◽  
Pyrochlore Phase ◽  
Annealing Process ◽  
Lead Silicate ◽  
Pzt Thin Films ◽  
Reliability Parameters ◽  
Post Annealing ◽  
Structure Changes

ABSTRACTThe crystal structure, surface morphology and electrical properties of PbSiOx (PSO) doped Pb(Zr,Ti)O3 (PZT) thin films were systematically investigated. The starting solutions of PSO-doped PZT were prepared by mixing sol-gel solutions of PZT and PSO. RTA-calcined thin films were crystallized by means of an oxygen partial pressure controlled post-annealing process. After the calcining process, lightly doped PZT thin films containing an amount of PSO dopant less than 1.0 at.% exhibit (111)-preferred orientation, and fine grains having a diameter of 50 nm and column-like structure. As the amount of PSO dopant is increased to 5.0 at.%, the (111) peaks becomes obscure and the (100) peaks together with the minor (110) peaks becomes dominant. The column-like structure changes into a plate-like structure having coarse grains whose diameter exceeds 500 nm. Further increasing the level of PSO dopant to 20.0 at.% causes the appearance of a pyrochlore phase having an extremely smooth surface without apparent grains. On the other hand, after the post-annealing process, the pyrochlore phase seen in the heavily doped PZT remarkably disappears, replaced by a perovskite phase together with PSO. The remnant polarization (Pr) gradually decreases as the amount of PSO dopant increases. The break down voltage, fatigue, imprint and other reliability parameters are improved within the proper doping range.

Microstructural development in sol-gel derived lead zirconate titanate thin films: The role of precursor stoichiometry and processing environment

1996 ◽  
Vol 11 (8) ◽  
pp. 2076-2084 ◽  
Author(s):  
M. J. Lefevre ◽  
J. S. Speck ◽  
R. W. Schwartz ◽  
D. Dimos ◽  
S. J. Lockwood
Keyword(s):  
Thin Films ◽  
Heat Treatment ◽  
Lead Zirconate Titanate ◽  
Single Phase ◽  
Perovskite Phase ◽  
Sol Gel ◽  
Lead Zirconate ◽  
Microstructural Development ◽  
Zirconate Titanate

The role of precursor stoichiometry and local firing environment on the microstructural development of sol-gel derived lead zirconate titanate (PZT) thin films was investigated. Typically, excess Pb is added to films to compensate for PbO volatilization during heat treatment. Here, it is shown that the use of stoichiometric precursors with either a PbO atmosphere powder or a PbO overcoat during the crystallization heat treatment is an attractive and viable alternative method for control of film stoichiometry. Using these approaches, we have fabricated single phase perovskite thin films with microstructures and electrical properties (Pr ∼ 36 μC/cm2 and Ec ∼ 45 kV /cm) comparable to those of films using optimized solution chemistries and excess Pb additions. The potential advantage of increasing PbO partial pressure, or activity, during firing versus excess Pb additions is discussed from the standpoint of a proposed crystallization scenario based on the kinetic competition between Pb loss and the nucleation and growth rates of the perovskite phase.

Residual Stress in Pzt Thin Films and its Effect on Ferroelectric Properties

1991 ◽  
Vol 243 ◽  
Author(s):  
Terry J. Garino ◽  
Mark Harrington
Keyword(s):  
Thin Films ◽  
Residual Stress ◽  
Dielectric Constant ◽  
Remanent Polarization ◽  
Coefficient Of Thermal Expansion ◽  
Perovskite Phase ◽  
Ferroelectric Properties ◽  
External Stress ◽  
Circular Section ◽  
Pzt Thin Films

AbstractThe residual stress in solution derived Pb(Zr.53Ti.47)o3, PZT 53:47, films was determined by measuring the bending of the substrate due to the stress. The substrate consisted of an oxidized (100) silicon wafer with 300 nm coating of platinum. In all cases the stress was tensile. Films fired at a temperature in the range where pyrochlore formation occurs (500° to 575°C) had the highest residual stresses, 200 to 350 MPa, whereas those fired at higher temperatures, 600° to 650°C, where the perovskite phase forms had stresses of 100 to 200 MPa. Stress measurements made during film firing indicate that the pyrochlore containing films had higher residual stress because their coefficient of thermal expansion was much larger than that of predominantly perovskite films. The effect of the amount of stress on ferroelectric properties was studied by making measurements on a film with and without the application of an external stress. The external stress was applied by bending a circular section of the substrate, which effectively lowered the amount of tensile stress in the film by ∼30%. Decreasing the stress in this manner was found to increase the remanent polarization by ∼11% and the dielectric constant by ∼2%.

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