• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.11 no.1
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• pp.57-61
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• 1998

In this study, PLZT stock solutions were prepared by Sol-Gel processing after the compositions were selected in the memory region of PLZT bulk phase diagram. PLZT solutions were deposited on the ITO glass substrate by spin-coating method. The thin films were annealed by rapid thermal processing. The electric characteristics, hysteresis loop, C-V characteristics of thin films in the memory region were measured in order to investigate the electrical characteristics of PLZT thin films. In selected compositions the decrease in Zr/Ti ratio led to an increase in dielectric constant and the decrease in remanent polarization and coercieve field which brought about slim hysteresis loop.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1997.11a
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• pp.52-55
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• 1997

In this study, PLZT stock solutions were prepared by sol-gel processing to fabricate PLZT thin films. The stock solutions were spin-coated on ITO-glass and the film were annealed by rapid thermal annealing(RTA). The variation of tile crystallographic structure of the thin films and the phase transition with respect to it were observed using Raman spectra. Raman result showed that the band of spectra are broad as the amount of Zr substitution increased and specially, abrupt change occurs in the raman spectra upon crossing the tetragonal-rhombohedral phase boundry at 2/55/45 PLZT thin film. So, the fact that the crystallographic structure was transitted from tetragonal to rhombohedral structure was certified.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.12 no.4
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• pp.184-189
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• 2002

The electrical and optical properties of $(Pb_{0.91}La_{0.09})(Zr_{0.65}Ti_{0.35})O_3$(PLZT) thin films by MOCVD using ultrasonic spraying were investigated. To compensate the Pb loss by evaporation, 5 and 10 wt% of excess Pb was added to 0.2 M precursor. After deposition of films on ITO-coated glasses in oxygen atmosphere for 30 min, films were heated by in-situ RTA (rapid thermal annealing) method. When the films were heat treated at $600^{\circ}C$, perovskite single phase was obtained. The optical property of the film with 10 wt% excess Pb was excellent showing about 84 % of transmittance near 520 nm. The dielectric constant of the film was about 308 and the leakage current of the film was lower than the Pb excess 0, 5 wt% PLZT thin films.

• Journal of the Korean Ceramic Society
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• v.29 no.11
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• pp.870-876
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• 1992

Lead lanthanum zirconate titanate (PLZT, 6/65/35) powders, crack-free and dense thin films have been prepared by polymeric sol-gel process. Pyrolysis of the gel, crystallization and optical transmittance behavior of the PLZT thin film onto sapphire substrate have been studied. Esterification occurs during synthesis of PLZT complexation. Crystalline Pb phase was transiently formed near 450$^{\circ}C$. Content of perovskite phase in the films were increased with increasing thickness of film, but the kinetics of formation of perovskite phase in films was slower than that of powders. Transmittance of the films was decreased with increasing the temperature of heat treatment. Ferroelectric hysteresis loop measurements indicated increments of remanent polarization and coercive field for plenty more of perovskite phase.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.11 no.3
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• pp.237-241
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• 1998

In this study, PLZT stock solutions around x/65/35 (x=6~11) ferroelectric region were prepared by Sol-Gel method and deposited on ITO-glass by spin-coating method. The thin films were annealed by RTA(rapid thermal annealing). The variations of crystallographic structure of the thin films were observed using XRD and hysteresis curves, dielectric characteristics, and optical transmittances were measured in order to investigate the characteristics of the thin films. The thin films were crystallized at $750^{\circ}C$ for 5 min by RTA. Relative dielectric constant and optical transmittance increased with increasing La content, Ec and Pr were higher for thin films than for bulk materials.

• Journal of the Korean Vacuum Society
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• v.17 no.6
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• pp.560-565
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• 2008

$(Pb_{0.98}La_{0.08})(Zr_{0.65}Ti_{0.35})O_3$ (PLZT) thin films with $TiO_2$ buffer layers were deposited on Pt/Ti/$SiO_2$/Si substrates by an R.F. magnetron sputtering method in order to improve the ferroelectric characteristics of the films. And the ferroelectric properties and crystallinities of the PLZT thin films were investigated in terms of the effects of the post annealing temperatures of $TiO_2$ buffer layers between a platinum bottom electrode and PLZT thin film. The ferroelectric properties of the PLZT thin films improved as increasing of the post annealing temperatures of $TiO_2$ layers, thereby reaching their maximum at $600^{\circ}C$.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.11 no.2
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• pp.128-132
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• 1998

2/65/35 PLZT stock solution prepared by Sol-Gel processing was spin-coated on ITO coated glass and annealed by RTA(Rapid Thermal Annealing). The crystal structure of films was reported based on the observation of crystallization process and microstructure of the film fabricated at different fabrication condition. Films were crystallized into rhombohedral structure by annealing at $750^{\circ}C$ for 5 min. As the annealing temperature increased, the size of rosette structure of the films was grown up from $2.4{\mu}m$ to $15{\mu}m$, dielectric constant was increased, coercive field was decreased 33.82 kV/cm, remnant polarization was increased to 39.84 ${\mu}C/cm^2$ and Optical transmittance was decreased.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.38 no.3
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• pp.166-173
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• 2001

Hysteresis loops of the ferroelectric thin films such as PLZT(10/30/70), PLT(10) and PZT(30/70) was simulated using the field-dependent polarization model and compared to the measured loops. In case of PZT(30/70) thin film, as the real saturation or polarization at the applied voltage or larger than 5V appears slack and its value is quite different from the simulated one, it is deduced that the ferroelectric polarization of PZT(30/70) is generated not only by the pure dipoles but also by various electric charges. The drain current of quasi-MFISFET is expressed by using the square-law FET and field-dependent polarization models. The modeling results are analogous to the experimental values. The channel of quasi-MFISFET using PZT(30/70) forms more quickly compared to that of quasi-MFISFET using PLZT(10/30/70) or PLT(10) in the state of 'write' gate voltage of -10V. This may be because the decrease rate of the polarization in the PZT(30/70) thin film is 3~4 times more rapid than that of the polarization in the PLZT(10/30/70) or the PLT(10) thin film in the retention characteristics.

• Journal of the Korean Ceramic Society
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• v.34 no.10
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• pp.1060-1066
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• 1997

In this paper, the effects of La addition of PLZT thin film prepared by sol-gel method on the capacitor characteristics are investigated for gigabit generation DRAM applications. The addition of La on the PLZT capacitor results in a trade-off between charge storage density(Qc') and leakage current density(Jl). As La content increases, Qc' and permeability(εr) at 0V are reduced while Jl is significantly decreased. It is demonstrated that 5% La doping of PZT can substantially reduce Jl and also improve resistance to fatigue while incurring only minimal degradation of Qc'. Very low leakage current density (5×10-7 A/㎠ even at 125℃) and high charge storage density (100fC/㎛2) under VDD/2=1V conditions are achieved using 5% La doped PZT thin films for gigabit DRAM capacitor dielectrics. In addition, the fatigue and TDDB measurements indicate good reliability of the PLZT capacitors.

• Journal of Sensor Science and Technology
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• v.23 no.4
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• pp.224-228
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• 2014

The electrocaloric effect of 9/65/35 PLZT thin film fabricated by the sol-gel method, which has not been studied yet, was investigated for its structural, electrical properties as well as temperature change property. The relaxor ferroelectric property of 9/65/35 PLZT thin film was confirmed by examining its dielectric and electrical properties. The relaxor property can cause a more pronounced electrocaloric effect (ECE) in a wider temperature range than normal ferroelectric film. To avoid errors caused by using an indirect measurement method, the leakage current generated by increasing temperatures was minimized by using the optimal maximum electric field ($350kVcm^{-1}$) in the thin film. The largest temperature change ${\delta}T$ (0.23 K) and the electrocaloric strength ${\xi}$ (0.68 mkcm/kV), calculated by equations were obtained. The maximum field change ${\delta}E$ ($191kVcm^{-1}$) was in the vicinity of the curie temperature ($200^{\circ}C$).