• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.07a
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• pp.547-549
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• 2001

The dielectric constants and dielectric losses of ZrTiO$_4$thin films deposited by DC magnetron reactive sputtering were investigated. The paraelectric properties were measured in the 100kHz range. As the deposition temperature increased (up to 67$0^{\circ}C$), the dielectric losses (tan$\delta$) decreased (down to 0.017$\pm$0.007), while the dielectric constants ($\varepsilon$) were in the range of 35$\pm$7. Post annealing at 80$0^{\circ}C$ in oxygen for 2h reduced tan$\delta$ down to 0.005$\pm$0.001, higher than those of well-sintered bulk ZrTiO$_4$.

• Journal of Powder Materials
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• v.23 no.5
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• pp.379-383
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• 2016

A thick film of $Li_7La_3Zr_2O_{12}$ (LLZO) solid-state electrolyte is fabricated using the tape casting process and is compared to a bulk specimen in terms of the density, microstructure, and ion conductivity. The final thickness of LLZO film after sintering is $240{\mu}m$ which is stacked up with four sheets of LLZO green films including polymeric binders. The relative density of the LLZO film is 83%, which is almost the same as that of the bulk specimen. The ion conductivity of a LLZO thick film is $2.81{\times}10^{-4}S/cm$, which is also similar to that of the bulk specimen, $2.54{\times}10^{-4}S/cm$. However, the microstructure shows a large difference in the grain size between the thick film and the bulk specimen. Although the grain boundary area is different between the thick film and the bulk specimen, the fact that both the ion conductivities are very similar means that no secondary phase exists at the grain boundary, which is thought to originate from nonstoichiometry or contamination.

• Korean Journal of Materials Research
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• v.13 no.8
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• pp.497-502
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• 2003

Crystallographic characteristics and interfacial structures of $Al_2$$O_3$and $ZrO_2$dielectric films prepared by atomic layer chemical vapor deposition (ALCVD) were investigated at atomic scale by high-resolution transmission electron microscopy (HRTEM) and energy dispersive X-ray spectroscopy (EDS)/electron energy-loss spectroscopy (EELS) coupled with a field-emission transmission electron microscope. The results obtained from cross-sectional and plan-view specimens showed that the $Al_2$$O_3$film was crystallized by annealing at a high temperature and its crystal system might be evaluated as either cubic or tetragonal phase. Whereas the $ZrO_2$film crystallized during deposition at a low temperature of ∼$300^{\circ}C$ was composed of both tetragonal and monoclinic phase. The interfacial thickness in both films was increased with the increased annealing temperature. Further, the interfacial structures of X$ZrO_2$$O_3$and $ZrO_2$films were discussed through analyses of EDS elemental maps and EELS spectra obtained from the annealed films, respectively.

• Bulletin of the Korean Chemical Society
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• v.32 no.8
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• pp.2799-2801
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• 2011

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.07a
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• pp.365-366
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• 2005

PZT films are the most intensively investigated because PZT has advantages such as low processing temperature and large remnant values. In this paper, the microstructure and electric properties of $Pb(Zr_x,Ti_{(1-x)})O_3/BaTiO_3$ heterolayered thick films with Zr mole ranging from 30 to 70 % screen printed onto a alumina substrate were studied. $Pb(Zr_x,Ti_{(1-x)})O_3$ and $BaTiO_3$ powders were prepared by the sol-gel method. The $BaTiO_3$ powders were calcined at $700^{\circ}C$ for 2 hours. Structural properties of $Pb(Zr_x,Ti_{(1-x)})O_3/BaTiO_3$ multilayered thick films were investigated. As a result of the X-ray diffraction (XRD) analysis, $Pb(Zr_x,Ti_{(1-x)})O_3/BaTiO_3$ exhibited a perovskite polycrystalline phase without pyrochlore phase or any preferred orientation.

• Korean Journal of Materials Research
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• v.31 no.10
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• pp.546-551
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• 2021

To improve ferroelectric properties of PZT, many studies have attempted to fabricate dense PZT films. The AD process has an advantage for forming dense ceramic films at room temperature without any additional heat treatment in low vacuum. Thick films coated by AD have a higher dielectric breakdown strength due to their higher density than those coated using conventional methods. To improve the breakdown strength, glass (SiO₂-Al₂O₃-Y₂O₃, SAY) is mixed with PZT powder at various volume ratios (PZT-xSAY, x = 0, 5, 10 vol%) and coating films are produced on silicon wafers by AD method. Depending on the ratio of PZT to glass, dielectric breakdown strength and energy storage efficiency characteristics change. Mechanical impact in the AD process makes the SAY glass more viscous and fills the film densely. Compared to pure PZT film, PZT-SAY film shows an 87.5 % increase in breakdown strength and a 35.3 % increase in energy storage efficiency.

• Journal of the Korean Vacuum Society
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• v.6 no.S1
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• pp.75-79
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• 1997

Optical and mechanical characteristics of $TiO-2, ZrO_2 \;and\; SiO_xN_y$ thin films prepared by ion assisted deposition (IAD) were investigated. IAD films were bombarded by Ar or nitrogen ion beam from a Kaufman ion source while they were grown in as e-beam evaporator. The result shows that the Ae IAD increases the refractive index and packing density of $TiO_2 films close to those of the bulk. For $ZrO_2$ films the Ar IAD increases the average refractive index decreases the negative inhomogeneity of refractive index and reverses to the positive inhomogeneity. The optical properties result from improved packing density and denser outer layer next to air The Ar-ion bombardment also induces the changes in microstructure of $ZrO_2$ films such as the preferred (111) orientation of cubic phase increase in compressive stress and reduction of surface roughness. Inhomogeneous refractive index SiOxNy films were also prepared by nitrogen IAD and variable refractive index of $SiO_xN_y$ film was applied to fabricate a rugate filter.

• Journal of the Korean Chemical Society
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• v.57 no.5
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• pp.547-553
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• 2013

Zirconium oxide ($ZrO_2$) nano porous membranes were fabricated by electrochemical two-step anodization with an electropolished zirconium substrate in inorganic water-based and organic electrolyte systems containing small amounts of fluoride. Using two-step anodization and organic electrolytes, highly regular and ordered nanotubular $ZrO_2$ oxide layers can be compared with aqueous electrolytes. The morphology and size of the nano porous layers were characterized by FE-SEM (field emission scanning electron microscopy), XRD (X-ray diffraction), and EDS (energy dispersive spectroscopy). Luminescence properties were investigated by photoluminescence measurements.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1301-1302
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• 2007

The multilayered $Pb_{1.1}(Zr_{0.4}Ti_{0.6})O_{3}$/$Pb_{1.1}(Zr_{0.6}Ti_{0.4})O_{3}/Pb_{1.1}(Zr_{0.4}Ti_{0.6})O_{3}$[PZT(4060)/(6040)/(4060)] thin films were deposited by RF sputtering method on the Pt/TiO2/SiO2/Si substrate. We investigated the effects of deposition conditions on the structural and electrical properties of the multilayered PZT thin films. All the multilayered PZT thin films showed dense and homogeneous structure without the presence of the rosette structure. The dielectric properties such as dielectric constant, loss, remanent polarization of the multilayered PZT thin film were superior to those of single composition PZT(4060) and PZT(6040) films, and those values for the multilayered PZT(10/20/10) thin film were 903, 1.01% and $25.60{\mu}C/cm^2$. This study suggests that the design of the multilayered PZT thin films capacitor with tetragonal and rhombohedral phase should be an effective method to enhance the dielectric and ferroelectric performance in devices.

• Journal of the Korean Vacuum Society
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• v.19 no.1
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• pp.52-57
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• 2010

$BiFeO_3/Pb(Zr_{0.52}Ti_{0.48})O_3$(BFO/PZT) multilayer thin films have been prepared on a Pt/Ti/$SiO_2$/Si(100) substrate by chemical solution deposition. BFO single layer, BFO/PZT bilayer and multilayer thin films were studied for comparison. X-ray diffraction analysis showed that the crystal structure of all films was multi-orientated perovskite phase without amorphous and impurity phase. The leakage current density at 500 kV/cm was reduced by approximately four and five orders of magnitude by bilayer and multilayer structure films, compared with BFO single layer film. The low leakage current density leads to saturated P-E hysteresis loops of bilayer and multilayer films. In BFO/PZT multlayer film, saturated remanent polarization of $44.3{\mu}C/cm^2$ was obtained at room temperature at 1 kHz with the coercive field($2E_c$) of 681.4 kV/cm.