Low Temperature Formation of Ferroelectric thin Films

1992 ◽  
Vol 271 ◽  
Author(s):  
Chi Kong Kwok ◽  
Seshu B. Desu
Keyword(s):  
Thin Films ◽  
Low Temperature ◽  
Lead Zirconate Titanate ◽  
Transformation Temperature ◽  
Perovskite Phase ◽  
Lead Zirconate ◽  
Phase Transformation Temperature ◽  
Seeding Layer ◽  
Rate Limiting Step ◽  
Nucleation Sites

ABSTRACTTwo novel processes have been developed to lower the transformation temperature of ferroelectric lead zirconate titanate (PZT) thin films with high Zr/Ti ratio. One process makes use of high pressure and the other process uses seeding to encourage the transformation.A previous study has shown that nucleation is the rate-limiting step for the perovskite formation. Therefore, any process that enhances the kinetics of the nucleation will likely decrease the transformation temperature. In this process, a very thin seeding layer, which has a low effective activation energy for perovskite formation, is used to provide nucleation sites needed for the low temperature perovskite formation. In this study, the pyrochlore to perovskite phase transformation temperature of PbZrxTi1−xO33 films of high Zr/Ti ratio (e.g. x = 53/47) can be lowered by as much as 100°C.

Low temperature perovskite formation of lead zirconate titanate thin films by a seeding process

1993 ◽  
Vol 8 (2) ◽  
pp. 339-344 ◽  
Author(s):  
Chi Kong Kwok ◽  
Seshu B. Desu
Keyword(s):  
Thin Films ◽  
Low Temperature ◽  
Lead Zirconate Titanate ◽  
Transformation Temperature ◽  
Perovskite Phase ◽  
Lead Zirconate ◽  
Grain Structure ◽  
Phase Transformation Temperature ◽  
Seeding Layer ◽  
Zirconate Titanate

A two-step seeding process has been developed to lower the transformation temperature and modify the grain structure of ferroelectric lead zirconate titanate (PZT) thin films with high Zr/Ti ratio. Previous study has shown that nucleation is the rate-limiting step for the perovskite formation. Therefore, any process that enhances the kinetics of nucleation is likely to decrease the transformation temperature. In this process, a very thin (45 nm) seeding layer of PbTiO3, which has a low effective activation energy for perovskite formation, was used to provide nucleation sites needed for the low temperature perovskite formation. In this study, we have shown that the pyrochlore-to-perovskite phase transformation temperature of PbZrxTi1−xO3 films of high Zr/Ti ratio (e.g., x = 53/47) can be lowered by as much as 100 °C. The grain size of these films can also be substantially modified by this two-step approach.

The Pyrochlore-to-Perovskite Transformation in Solution-Derived Lead Zirconate Titanate Thin Films

1994 ◽  
Vol 361 ◽  
Author(s):  
James A. Voigt ◽  
B.A. Tuttle ◽  
T.J. Headley ◽  
D.L. Lamppa
Keyword(s):  
Thin Films ◽  
Grain Boundary ◽  
Grain Growth ◽  
Lead Zirconate Titanate ◽  
Volume Change ◽  
Crystallographic Orientation ◽  
Crystallization Process ◽  
Perovskite Phase ◽  
Lead Zirconate ◽  
Two Dimensional

ABSTRACTWe have characterized the pyrochlore-to-perovskite crystallization process in solution-derived Pb(Zr0.20Ti0.80)O3 thin films on (100) MgO single crystal substrates. It has been determined that the perovskite phase nucleated preferentially at the film/MgO interface out of a nanocrystalline (≈100Å grains) pyrochlore matrix. During the early stages of the pyrochlore-to-perovskite conversion process, perovskite growth proceeded nearly isotropically from the substrate to form hemispherically shaped grains. Deviations from isotropie growth were shown to result from a growth dependence based on the crystallographic orientation of a growing perovskite grain relative to the orientations of pyrochlore grains being transformed. The volume change that occurs during the pyrochlore-to-pervoskite transformation along with two-dimensional grain growth has been used to develop a mechanism for formation of porosity that commonly is concentrated in grain boundary regions.

Microstructural development in solution-derived PZT thin films

1994 ◽  
Vol 52 ◽  
pp. 578-579
Author(s):  
T. J. Headley ◽  
B. A. Tuttle ◽  
J. A. Voigt ◽  
J. R. Michael
Keyword(s):  
Thin Films ◽  
Lead Zirconate Titanate ◽  
Capital Investment ◽  
Perovskite Phase ◽  
Amorphous Film ◽  
Phase Evolution ◽  
Lead Zirconate ◽  
Solution Chemistry ◽  
Microstructural Development ◽  
Pzt Thin Films

Lead zirconate titanate (PZT) thin films are of technological interest for a variety of electronic and optical applications such as nonvolatile memories, decoupling capacitors, infrared detectors, and optical storage media. Fabrication of PZT films by solution deposition techniques is attractive because of uniform, stoichiometric control at the molecular level, ease of processing, and both low capital investment and total cost. Control of phase evolution, microstructure, crystallite size and orientation, and ferroelectric domain assemblage during processing is essential to optimize electrical and/or optical properties of the films. Factors which play a major role in controlling these parameters are details of the solution chemistry and mixing, thermal processing, Pb stoichiometry, Zr/Ti ratio, and substrate characteristics. Electron microscopy techniques have been used extensively to correlate microstructural features with film processing parameters as will be emphasized in this presentation.As annealing temperature is increased, phase evolution in PZT thin films typically proceeds from amorphous to pyrochlore to the ferroelectric perovskite phase. Fine-grained pyrochlore crystallizes from the amorphous film at low annealing temperatures and also precedes crystallization of the perovskite phase at higher temperatures. There is evidence that the Zr/Ti stoichiometry influences the microstructure of the amorphous-to-pyrochlore transformation.

Structural and electrical properties of excess PbO doped Pb(Zr0.52Ti0.48)O3 thin films using rf magnetron sputtering method

1998 ◽  
Vol 13 (12) ◽  
pp. 3436-3441 ◽  
Author(s):  
Tae Song Kim ◽  
Dong Joo Kim ◽  
Jeon Kook Leea ◽  
Hyung Jin Jung
Keyword(s):  
Thin Films ◽  
Dielectric Constant ◽  
Electrical Properties ◽  
Lead Zirconate Titanate ◽  
Perovskite Phase ◽  
Rf Magnetron Sputtering ◽  
Xrd Analysis ◽  
Lead Zirconate ◽  
Hysteresis Curve ◽  
Grown Film

Well-crystallized Pb(Zr0.52Ti0.48)O3 thin films (4000 Å thickness) can be synthesized on Pt/Ti/SiO2/Si(100) substrate at a temperature as low as 520 °C. The polycrystalline lead zirconate titanate (PZT) perovskite phase formation was confirmed with x-ray diffraction (XRD) analysis, and growth morphologies were studied with a scanning electron microscope (SEM). The electrical properties of PZT thin films were characterized through P-E hysteresis curve, dielectric constant, and loss, fatigue, and leakage current measurements. Remanent polarization (Pr) and coercive field (Ec) of as-grown film were 8–30 μC/cm2 and 24–64 kV/cm with the variation of applied voltage (5–15 V). The post-annealing enhances the electrical properties even at 500 °C, which is below the as-grown temperatures (520 °C). The average polarization loss after applying rectangular pulse (Vp-p = 10 V) up to 1011 cycles was 40.9% for a 300 μm small dot and 22% for a 500 μm large dot, which are relatively improved values for platinum electrode. The values of dielectric constant (ε′) and tan δ measured with small signal sign wave (1 V, 10 kHz) were 1207 and 0.066 in the case of as-grown film.

Compositional and Structural Properties of Sputtered Plzt Thin Films

1991 ◽  
Vol 243 ◽  
Author(s):  
P.J. Borrelli ◽  
P.H. Ballentine ◽  
A.M. Kadin
Keyword(s):  
Thin Films ◽  
Substrate Temperature ◽  
Lead Zirconate Titanate ◽  
Perovskite Phase ◽  
Target Surface ◽  
Rf Magnetron Sputtering ◽  
Lead Zirconate ◽  
Ferroelectric Capacitor ◽  
Target Composition ◽  
Loose Powder

AbstractThin films of lanthanum-modified lead zirconate-titanate (PLZT) were prepared by rf magnetron sputtering from a single oxide target onto a heated substrate. The target consisted of Pbl-xLaxZryTi1-yO3 with composition close to x=8% and y= 65%, either as a loose powder or a solid sintered disk. Under appropriate conditions, the desired perovskite phase formed in situ without any subsequent post-anneal. Film composition and structure were correlated with deposition parameters, including substrate temperature, target composition, gas pressures, and target aging. For deposition onto MgO or A12O3 crystalline substrates, perovskite PLZT films formed if there was sufficient Pb at the target surface, sufficient oxygen in the sputter gas (≈ 50%), and a substrate temperature >≈600°C. Target heating led to excessive Pb loss from the loose powder target; this was much less significant for the solid target. In addition, it was found that deposition onto an epitaxial perovskite substrate promoted formation of the perovskite phase, leading to an epitaxial film. A prototype ferroelectric capacitor was fabricated by depositing a conducting perovskite film (the high-Tc superconductor YBa2 Cu3O7 ) on a perovskite substrate, sputtering PLZT on top, with Ag for a top electrode. Measurements indicate a remanent polarization of 5 μC/cm2 and a coercive field of 900 V/cm.

Effect of Microwave Irradiation on Rapid Crystallization of Ferroelectric Lead Zirconate Titanate Thin Films

2013 ◽  
Vol 750 ◽  
pp. 220-223
Author(s):  
Xian Wei Wang ◽  
Zhan Jie Wang ◽  
Yan Na Chen ◽  
Yu Qing Zhang ◽  
Zhi Dong Zhang
Keyword(s):  
Thin Films ◽  
Microwave Irradiation ◽  
Lead Zirconate Titanate ◽  
Perovskite Phase ◽  
Lead Zirconate ◽  
Process Time ◽  
Rapid Crystallization ◽  
Furnace Process ◽  
Conventional Furnace ◽  
Pzt Films

Ferroelectric Pb(Zr0.52Ti0.48)O3 (PZT) thin films rapidly crystallized by microwave irradiation were compared with those obtained by conventional furnace process. The PZT films under microwave irradiation at 650 °C for 60 s were crystallized well in to the perovskite phase, and showed butter electrical properties than those crystallized by conventional furnace annealing at 650 °C for 30 min. It is clear that microwave irradiation is effective for obtaining well-crystallized PZT films with good properties in a short process time.

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