• Journal of Mechanical Science and Technology
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• v.19 no.8
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• pp.1544-1553
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• 2005

In this article, a micro cantilever array actuated by PZT films is designed and fabricated for micro fluidic systems. The design features for maximizing tip deflections and minimizing fluid leakage are described. The governing equation of the composite PZT cantilever is derived and the actuating behavior predicted. The calculated value of the tip deflection was 15 ${\mu}m$ at 5 V. The fabrication process from SIMOX (Separation by oxygen ion implantation) wafer is presented in detail with the PZT film deposition process. The PZT films are characterized by investigating the ferroelectric properties, dielectric constant, and dielectric loss. Tip deflections of 12 ${\mu}m$ at 5 V are measured, which agreed well with the predicted value. The 18 ${\mu}l/s$ leakage rate of air was observed at a pressure difference of 1000 Pa. Micro cooler is introduced, and its possible application to micro compressor is discussed.

• Proceedings of the KIEE Conference
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• 1994.07b
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• pp.1454-1456
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• 1994

$Pb(Zr_{0.52}Ti_{0.48})O_3$ ceramic thin films were fabricated from an alkoxide-based solution by Sol-Gel method. $Pb(Zr_{0.52}Ti_{0.48})O_3$ ceramic thin films were formed by spin coating method on $Pt/SiO_2/Si$ substrate at 3000rpm for 30 seconds. The coating process was repeated 6 times and then heat-treated at temperature between 500 - $800[^{\circ}C]$ for 1 hour. The final thickness of the thin films were about 4800[A]. The 100% ferroelectric perovskite phases precipitated under the heat treated at $700[^{\circ}C]$ for 1 hour. $Pb(Zr_{0.52}Ti_{0.48})O_3$ thin films heat-treated at $700[^{\circ}C]$ for 1 hour showed good dielectric constant (812) property.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.14 no.9
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• pp.731-735
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• 2001

S $r_{0.89}$B $i_{2.4}$T $a_2$ $O_{9}$ (SBT) thin films are deposited on Pt-coated electrode(Pt/Ti $O_2$/ $SiO_2$/Si) using RF magnetron sputtering method. In the XRD pattern, the SBT thin films had (105) orientation. As annealing temperature was increased from $600^{\circ}C$ to 85$0^{\circ}C$, the intensities of peak were increased. In the SEM images, Bi-layered perovskite phase was crystallized above $650^{\circ}C$ and rod-like grains grew above 75$0^{\circ}C$. The maximum remanent polarization and the coercive electric field at annealing temperature of 75$0^{\circ}C$ are 11.60$\mu$C/$\textrm{cm}^2$ and 48kV/cm respectively. The dielectric constant and leakage current density at annealing temperature of 75$0^{\circ}C$ are 213 and 1.01x10$^{-8}$ A/$\textrm{cm}^2$, respectively. The fatigue characteristics of SBT thin filmsdid not change up to 10$^{10}$ switching cycles.s.s.

• Proceedings of the KIEE Conference
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• 2000.07c
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• pp.1631-1633
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• 2000

A study was carried out on the effect of VDF mol%, on the phase transition presented by P(VDF/TrFE) copolymer cast from dimethylformamide(DMF) solution with molar ratios 70/30 and 80/20. The results from dielectric spectrum and differential scanning calorimetry(DSC) showed that the phase transitions from ferroelectric to paraelectric phase(Curie transition) were observed The Curie point slightly has shifted to high temperature with increasing in VDF mol%, however, the melting point has shifted to low temperature.

• Proceedings of the KIEE Conference
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• 1996.11a
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• pp.245-247
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• 1996

The ferroelectric $Pb(Zr_xTi_{1-x})O_3$ (20/80, 80/20) heterolayered thin films were fabricated from an alkoxide-based by Sol-Gel method. The PZT(20/80) and PZT(80/20) stock solution were made and spin-coated on the Pt/Ti/$SiO_2$/Si substrate by turns. Each layers were baked to remove the organic materials at 300[$^{\circ}C$] for 30[min]. and sintered at 650[$^{\circ}C$] for 1[hr]. This procedure was repeated 5 times. At this time the thickness of thin films were about 4000[$\AA$]. Relative dielectric constant and remanent polarization of the PZT heterolayered thin films were 1200, 27.10 [${\mu}C/cm^2$], respectively.

• 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.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.11a
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• pp.160-160
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• 2009

In recent years, the merging of nanomaterials and nano-technology into electro-optic (EO) device technology such as liquid crystal displays (LCDs) has attracted much attention because of their unique electro- and magneto-optic properties and novel display applications. One example of hybrid LC-inorganic systems is semiconductor nanorods added to LC for their strong reorientation effect and tunable refractive index. Doping of nanoparticles in LC or polymers can lead to changes in performance characteristics such as electro-optical, dielectric, memory effect, phase behavior, etc. Due to the tunability of LCDs with mixed inorganic materials, low voltage operation of a LC system can also be achieved using the significant electro-optical effect achieved through suspension of ferroelectric nanoparticles in NLC.

• Journal of the Korean Ceramic Society
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• v.19 no.4
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• pp.300-308
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• 1982

A new perovskite type compound, (Pb1a-χKy□χ-y) (Zr0.33Ti0.67)O3-χ+y/2 was proposed and synthesized by "Wet-Dry Combination Technique". This defect ferroelectric material was characterized by partial substitutions of K+ for Pb+2 in Pb(Zr0.33Ti0.67)O3. This material was mono-phasic perovskite compound at 800℃ for 1hr., but ZrO2 was more or less isolated from the (Pb1a-χKy□χ-y) (Zr0.33Ti0.67)O3-χ+y/2. As a result, snitering temperature, sintered density, curie temperature, and dielectric constant of test pieces decreased and a-axis was nearly constant, while c-axis gradually decreased with the value x in the region of tetragonal phase of PZT. It was also recognized that the defect structure caused by adding K+ was found in both A-site cation and O-site anion vacancies in the defect PZT.

• Proceedings of the Materials Research Society of Korea Conference
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• 2003.03a
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• pp.38-38
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• 2003

PTO/PZO 초격자 박막은 박막 계면에 응력이 발생하여 기존의 박막처럼 size effect가 적용되지 않고 두께가 감소해도 높은 유전상수를 갖는다. Antiferroelectric PbZrO$_3$(PZO)와 ferroelectric PbTiO$_3$(PTO)를 적층 성장시킨 초격자는 400도에서 성장한 (100) Pt/SiO$_2$기판 위에 rf magnetron sputtering으로 증착하였다. PTO/PZO의 증착 주기는 30(PTO $_{4unti cells}$/PZO $_{4unti cells}$) 에서 1(PTO $_{125unti cells}$/PZO $_{125unti cells}$)까지 두께의 변화를 주어 준비했고 초격자 박막의 전체두께는 100nm로 고정시켰다. XRD결과, PTO/PZO는 주기에 따라 초격자의 특성인 main peak과 satellite peak을 관찰 할 수 있었다. 초격자의 주기가 감소함에 따라 2$\theta$값이 증가하고 평균 d 값이 감소되면서 PTO층에 뒤틀림이 증가하였다. PTO층의 뒤틀림 증가로 인해 superlattice의 주기가 증가함에 따라 초격자의 유전율이 증가하였고 강유전성이 향상되었다.향상되었다.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.20 no.2
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• pp.65-68
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• 2010

$Sr_{0.6}Ba_{0.4}Nb_2O_6$ (60SBN) and $Sr_{0.75}Ba_{0.35}Nb_2O_6$ (75SBN) single crystals were grown by Czochralski method. Growing direction was <001>, and as-grown crystals has well-developed (001) plane. Temperature- and frequency dependence of dielectric constant represent relaxor ferroelectrics. 60SBN has wider optical transmittance than 75SBN.