• Proceedings of the KIEE Conference
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• 2006.07a
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• pp.577-578
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• 2006

In this paper, PZT(20/80) thick films were fabricated by the screen-printing method. And the PZT(80/20) coating solution was synthesized by the sol-gel method. PZT(20/80) thick films were screen-printed on the alumina substrates. PZT(80/20) thin film was spin-coated on the PZT(20/80) thick films to obtain densification. And the structural and electrical properties of PZT thick films were investigated with variation of sintering temperature. The PZT specimen sintered at 650f showed good relative dielectric constant of 219 and dielectric loss of 2.45%. Also the remanent polarization and the coercive field were 16.48${\mu}C/cm^2$ and 35.48kV/cm, respectively.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.11a
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• pp.212-213
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• 2006

BSCT(60/30/10) powder specimens were fabricated by sol-gel method and BSCT thick films were fabricated by screen-printing method. The coating and drying procedure was repeated 6 times. Then the structural properties as a function of the sintering temperature. As a result of the TG-DTA, exothermic peak was observed at around $670^{\circ}C$ due to the crystalline phase. The BSCT sintered at $1430^{\circ}C$ showed the cubic perovskite structure. The prosity and thickness of the BSCT thick films was decreased with sintering temperature. The thickness of BSCT thick films at $1420^{\circ}C$ was approximately $40{\mu}m$.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.11a
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• pp.338-341
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• 2002

$(Ba_{1-x}Sr_{0.4}Ca_x)TiO_{3}$ (x=0.10, 0.15, 0.20) powders were prepared by the sol-gel method and BSCT thick films were fabricated by the screen-printing method. Their structural and dielectric properties were investigated with variation of composition ratio and $Al_{2}O_{3}$ doping contents. As results of the X-ray diffraction and microstructure analysis, the grain size of BSCT thick films was decreased with increasing $Al_{2}O_{3}$ amount. The thickness of BSCT thick films by 4-coating/drying is about $110{\sim}120{\mu}m$. The tunability increased with decreasing Ca content, and the BSCT(50/40/10) specimen doped with 1.0wt% $Al_{2}O_{3}$ showed the highest value of 12.94% at 5kV /cm.

• Proceedings of the KIEE Conference
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• 2006.07b
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• pp.1243-1244
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• 2006

In this paper, PZT(20/80) thick films were fabricated by the screen-printing method. And the PZT(80/20) coating solution was synthesized by the sol-gel method. PZT(20/80) thick films were screen-printed on the alumina substrates. PZT(80/20) thin film was spin-coated on the PZT(20/80) thick films to obtain densification. And the structural and electrical properties of PZT thick films were investigated with variation of sintering temperature. The PZT specimen sintered at $650^{\circ}C$ showed good relative dielectric constant of 219 and dielectric loss of 2.45%. Also the remanent polarization and the coercive field were $16.48{\mu}C/cm^2$ and 35.48kV/cm, respectively.

• Transactions of Materials Processing
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• v.11 no.7
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• pp.569-574
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• 2002

Recently, thick PZT films are required for the cases of micro piezoelectric devices with high driving force, high breakdown voltage and high sensitivity, and so on. In this work, thick PZT films were fabricated by Sol-Gel multi-coating method. Microstructures, and electrical properties of films were investigated by XRD, FESEM, impedance analyzer, and P-E hysteresis. PZT films with 2.7$mu extrm{m}$ to 4.4${\mu}{\textrm}{m}$ thickness were fabricated. Dielectric constant, loss, remnant polarization and coercive field of them were 880~1650 at 1kHz, 2~3% at 1kHz, 26~32 $\mu$C/$ extrm{cm}^2$, and 33~60kV/cm, respectively. Also a transverse piezoelectric coefficient $(e_{31,f})$ measurement system was fabricated and tested for thick film samples.

• Proceedings of the KIEE Conference
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• 2006.07c
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• pp.1703-1704
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• 2006

In this paper, PZT(20/80) thick films were fabricated by the screen-printing method. And the PZT(80/20) coating solution was synthesized by the sol-gel method. PZT(20/80) thick films were screen-printed on the alumina substrates. PZT(80/20) thin film was spin-coated on the PZT(20/80) thick films to obtain densification. And the structural and electrical properties of PZT thick films were investigated with variation of sintering temperature. The PZT specimen sintered at $650^{\circ}C$ showed good relative dielectric constant of 219 and dielectric loss of 2.45%. Also the remanent polarization and the coercive field were $16.48{\mu}C/cm^2$ and 35.48kV/cm, respectively.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.13 no.2
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• pp.68-72
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• 2003

In this paper, we developed a new thick photoresist fabrication technology for 3-dimensional microstructures. In general, like as AZ photoresist was coated with thin film thickness about 1 $\mu\textrm{m}$ to 30 $\mu\textrm{m}$, but photoresist like SU-8 has thickness of several tens $\mu\textrm{m}$ or more and high aspect ratio. When we fabricate a microstructure using the thick photoresist like SU-8, cracks on the SU-8 thick photoresist are appeared by stress which was caused by sudden cooling down during bake of the thick photoresist spun on wafer. Thus, it was hard to fabricate the microstructure using the thick photoresist for electroplating. In this paper, we developed a new process to produce a 3-dimensional microstructure without the crack by stress through a suitable thick photoresist coating, time control of cool down and time control of PEB (Post Expose Bake).

• Proceedings of the KIEE Conference
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• 2005.11a
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• pp.71-73
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• 2005

Ferroelectric PZT heterolayered thick films were fabricated by the alkoxide-based sol-gel method. PZT(20/80) and PZT(80/20) paste were made and alternately screen-printed on the alumina substrates. The coating and drying procedure was repeated 4 times to form the heterolayered thick films. The thickness of the PZT heterolayered thick films was approximately 60 mm. All PZT thick films showed the typical XRD patterns of a perovskite polycrystalline structure. The relative dielectric constant and the dielectric loss of the PZT thick films sintered at $1050^{\circ}C$ were 1382 and 1.90%, respectively. The remanent polarization and coercive field of the PZT thick films sintered at $1050^{\circ}C$ were $14.15{\mu}C/cm^2$ and 19.13kV/cm, respectively.

• Korean Journal of Materials Research
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• v.27 no.5
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• pp.289-293
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• 2017

$Y_2Ti_2O_7$ nanoparticles (0.3 mol%) have been successfully synthesized by the co-precipitation process. The samples, adjusted to pH7 with ammonia solution as catalyst and calcined at $700{\sim}900^{\circ}C$, exhibit very fine particles with close to spherical shape and average size of 10-30 nm. It was possible to control the size of the synthesized $Y_2Ti_2O_7$ particles by manipulating the conditions. The $Y_2Ti_2O_7$ nanoparticles were coated on a glass substrate by a dipping coating process with inorganic binder. The $Y_2Ti_2O_7$ solution coated on the glass substrate had excellent adhesion of 5B; pencil hardness test results indicated an excellent hardness of 6H. The thickness of the thick film was about $30{\mu}m$. Decomposition of MB on the $Y_2Ti_2O_7$ thin film shows that the photocatalytic properties were excellent.

• Journal of the Korean Ceramic Society
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• v.34 no.8
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• pp.908-913
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• 1997

Multilayer NbCxC1-x/Y2O3/Ti were sputter-coated on the alumina substrate, starting with a 0.7 ㎛ thick NbCxC1-x layer grown on substrate, followed by 0.7 ㎛ thick Y2O3 layer and 1 ㎛ thick Ti layer. To find out the optimum conditions for thickness uniformity and adhesion, sputtering works have been done with the variation of sputtering power and Ar pressure. After vacuum annealing at 950℃ and 1000℃, the thermal stability of the NbCxC1-x/Y2O3/Ti coated alumina substrates has been investigated by peel off test. The coating scheme didn't cause any debonded layer after an annealing at 950℃ for 3hrs. However, it was peeled off after annealing at 1000℃ for 3hr. It was found that the thermal stability of Al2O3/NbCxC1-x/Y2O3/Ti coating scheme changed with the NbCxC1-x composition.