• Transactions on Electrical and Electronic Materials
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• 제9권3호
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• pp.91-95
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• 2008

In this study, in order to develop the composition ceramics for low loss multilayer piezoelectric actuator application, $Pb(Zn_{1/2}W_{1/2})O_3-Pb(Mn_{1/3}Nb_{2/3})O_3-Pb(Zr,Ti)O_3$ (abbreviated as PZW-PMN-PZT)ceramics according to the amount of $MnO_2$ addition were fabricated using two-stage calcinations method. And also, their dielectric and piezoelectric properties were investigated. At the 0.2 wt% $MnO_2$ added PZW-PMN-PZT ceramics sintered at $930^{\circ}C$, density, electromechanical coupling factor $k_p$, dielectric constant ${\varepsilon}_r$, piezoelectric $d_{33}$ constant and mechanical quality factor $Q_m$ showed the optimum value of $7.84g/cm^3$, 0.543, 1,392, 318.7 pC/N, 1,536, respectively for low loss multilayer ceramics actuator application.

• Proceedings of the Korean Ceranic Society Conference
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• 한국세라믹학회 2002년도 추계총회 및 연구발표회 초록집
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• pp.88.2-88
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• 2002

• Electrical & Electronic Materials
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• 제8권3호
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• pp.261-266
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• 1995

In this study, PZT solutions added impurities of Yttrium acetate were prepared by sol-gel processing and were deposited on Pt/ $SiO_{2}$/Si substrates at 5000 rpm for 20 sec. using spin-coating method. Coated films were annealed at 700-750.deg. C for 30 min. using conventional furnace method. Variations of the crystallographic structure and microstructure of PZT thin films with adding impurities were observed using XRD and SEM, and the electrical properties, such as relative permittivity, tan .delta., hysteresis curves and leakage currents, were measured. As the yttrium contents were increased, the remanent polarization and coercive field were decreased. Variations of remanent polarizations and coercive fields of pure and yttrium doped specimens according to polarization reversal cycles were observed using hysteresis measurement. PZT thin films added $Y^{3+}$ ions were completely crystallized at 750.deg. C. $Y^{3+}$ ions, as donor impurity, substituted Pb.sup 2+/ ions located at A-site of perovskite structure. By substitution of $Y^{3+}$ ions, leakage currents became less by decreasing the space charges. Degradation of remanent polarizations of Yttrium added specimens after fatigue was not observed and coercive fields increased more than those of pure PZT thin films.

• The Korean Journal of Ceramics
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• 제6권1호
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• pp.64-67
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• 2000

Reactively sputtered $Pb(Zr,Ti)O_3$(PZT) films on $IrO_2$and Ir were evaluated with particular consideration on interface properties. The $IrO_2$and Ir were previously annealed at $650^{\circ}C$ in $O_2$or $N_2$atmosphere, respectively. There was no appreciable roughening in the interface of the $PZT/IrO_2$respective to that of the PZT/Ir; the rms roughness of $IrO_2$and Ir was about 3nm and 10nm, respectively. The ferroelectric properties of the $PZT/IrO_2$were found to be better than that of the PZT/Ir; however, the leakage current of the $PZT/IrO_2$was slightly larger than that of the PZT/Ir. The $PZT/IrO_2$thin films did not exhibit any fatigue up to $10^{11}$ cycles; the $P^*\;_r-P^r$ value decreased only from 16.6 to 14$\mu$C/$\textrm{cm}^2$ until $10^{12}$ polarization reversals. On the other hand, although thin $IrO_2$layer was formed between PZT and Ir, the PZT/Ir thin films began to undergo fatigue after $10^9$ polarization reversals.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• 제24권5호
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• pp.392-397
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• 2011

The effect of various post-annealing temperature to sputtered Pb(Zr,Ti)$O_3$ (PZT) thin films was investigated. The crystallization process, surface morphology and the electrical characteristics strongly depends on the rapid thermal annealing (RTA). In radio frequency (RF) sputtering methods, there were many papers mostly forcing on the crystal forming and the surface variations with different elements distribution (Pb, Ti, Zr, O) on the surface of the PZT layer. In this experiment, the post-annealing treatment promoted the Pb volatilization in PZT thin film and affected the Ti diffused throughout the Pt layer into the PZT layer. Second ion mass spectroscopy (SIMS) analysis was employed to show that the Pb element in the PZT layer was decreased at the same time the Ti element mass was slight decreased than Pb with increasing RTA temperature. That result prove the content of Pb affect the PZT thin film property.

• JSTS:Journal of Semiconductor Technology and Science
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• 제2권3호
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• pp.205-212
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• 2002

The growth characteristics of metal-organic chemical vapor deposition (MOCVD) $Pb(Zr_xTi_{1-x})O_3 (PZT) thin films were investigated for the application of high-density ferroelectric random access memories (FRAM) devices beyond 64Mbit density. The supply control of Pb precursor plays the most critical role in order to achieve a reliable process for PZT thin film deposition. We have monitored the changes in the microstructure and electrical properties of films on increasing the Pb precursor supply into the reaction chamber. Under optimized conditions, $Ir/IrO_2/PZT(100nm)/Ir capacitor shows well-saturated hysteresis loops with a remanent polarization (Pr) of $~28{\mu}C/textrm{cm}^2$ and coercive voltage of 0.8V at 2.5V. Other issues such as step coverage, compositional uniformity and low temperature deposition was discussed in viewpoint of actual device application.

• Journal of the Korea Academia-Industrial cooperation Society
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• 제8권5호
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• pp.995-999
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• 2007

The lead zirconate titanate (PZT) powders were synthesized to make the piezoelectric ceramics in low temperature as low as $900^{\circ}C$. To investigate the influence of additives on sintering of PZT, two kinds of sintering aids were made as follows; $wB_2O_3-xBi_2O_3-zCuO$and LiBiO2-CuO. The sintering aid, $1{\sim}3$ wt.% $LiBiO_2-CuO$, was added into these PZT powders and the specimens were fired at temperature in the range of $800{\sim}1200^{\circ}C$. The highest density was shown in the specimen with 1 wt.% $LiBiO_2-CuO$ as additive at temperature of $900^{\circ}C$. The sintered specimen were analyzed by X-ray diffraction(XRD) and scanning electron microscopy (SEM) was utilized to observe the microstructure, especially the densified morphology of specimens. In the XRD pattern, the well-crystallized PZT phase could be obtained in consequence of firing at $900^{\circ}C$. The scanning electron microscopy(SEM) was utilized to observe the structure of specimens after firing at $900^{\circ}C$. The densified perovskite structure of $PbZrTiO_3$ could be obtained by sintering at temperature as low as $900^{\circ}C$. The high sinterability of PZT ceramics was attributed to the low formation temperature of the liquid phase of additives.

• Journal of the Korean Ceramic Society
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• 제48권5호
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• pp.471-478
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• 2011

Investigations of crystal structure and phase transition of $Pb(Zr_{0.52}Ti_{0.48})O_3$ ceramics doped with A-site substitution impurity (La, Nd) or B-site substitution impurity (Sb, Nb) at 2 mol% concentration were carried out. X-ray diffraction patterns of impurities doped $Pb(Zr_{0.52}Ti_{0.48})O_3$ ceramics have been measured at pressures up to ~5 GPa with diamond anvil cell and synchrotron radiation. The patterns were obtained at room temperature using methanol-ethanol mixture as pressure-transmitting media. In order to refine the crystal structure, Rietveld analysis has been performed. The structures of impurities doped $Pb(Zr_{0.52}Ti_{0.48})O_3$ ceramics are tetragonal in space group P4mm at ambient pressure and are transformed into a cubic phase in space group Pm$\bar{3}$m as the pressure increases. In this study, when A-site substitution donor $La^{3+}$ or $Nd^{3+}$ ion was added to $Pb(Zr_{0.52}Ti_{0.48})O_3$ ceramics, the phase transition phenomena showed up at the pressure of 2.5~4.6 GPa, but when B-site substitution donor $Nb^{5+}$ or $Sb^{5+}$ ion was added to it, the phase transition appeared at relatively lower pressure of 1.7~2.6 GPa.

• Journal of the Korean Ceramic Society
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• 제37권1호
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• pp.6-11
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• 2000

Electron emission from the Pb(ZrxTi1-x)O3 ferroelectrics by pulsed electric field has been investigated as a function of Zr/Ti ratios such as 35/65, 50/50 and 65/35 below 250kV/cm. Electrons were emitted regardless of the applied field polarity to the rear electrode. When the negative field was applied to the rear electrode, the electron emission charge was more stable. It was proved that the electrons were emitted at the edge of the upper electrode. The emission charge increased in order of 65/35>50/50>35/65. The electron emission characteristics were dependent on the ferroelectric properties such as polarization and coercive field. The emission charge and emission threshold field were affected by the polarization change and the coercive field, respectively. This result explains that the electron emission is a field emission with polarization induced surface potential by a modified Fowler-Nordheim plot of emission charge.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 한국전기전자재료학회 2004년도 하계학술대회 논문집 Vol.5 No.1
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• pp.142-145
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• 2004

[ $Pb(Zr_{0.8}Ti_{0.2})TiO_3$ ] powder were prepared by the sol-gel method using a solution of Pb-acetate, Zr n-propoxide and Ti iso-propoxide. PZT thick film were fabricated by the screen printing method. and then the structural properties as a function of the sintering temperature were studied. PZT film thickness, obtained by four screen printing, was approximately $70{\sim}90{\mu}m$. The PZT thick film, sintered at $1050^{\circ}C$, showed deuse and uniform grain stractures and percent porosity of the thick film was 25.43%.