• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1998년도 추계학술대회 논문집
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• pp.247-250
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• 1998

Ferroelectric PZT(10/90)PZT(90/10) heterolayered thin films were fabricated by spin-coating method on the Pt/Ti/SiO$^2$/Si substrate alternately using PZT(10/90) and PZT(90/10) metal alkoxide solutions. The coating and heating procedure was repeated six times to form PZT heterolayered films. The surface, cross-sectional microstructures and thickness of the films were observed using scanning electron microscope(SEM). The relative dielectric constant and dielectric loss of the 5-coated PZT heterolayered films were 1331 and 4.8% respectively.

• 한국재료학회지
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• 제14권10호
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• pp.707-712
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• 2004

$BiFeO_3$ films grown on (111) $SrTiO_3$ substrate have a rhombohedral structure, identical to that of single crystals. On the other hand, films grown on (110) or (001) $SrTiO_3$ substrate are monoclinically distorted from the rhombohedral structure due to the epitaxial constraint. The easy axis of spontaneous polarization is close to [111] for the variously oriented films. Dramatically enhanced polarization and magnetization have been found for hetero-epitaxially grown $BiFeO_3$ thin films comparing to that of $BiFeO_3$ crystals. The results are explained in terms of an epitaxially-induced transition between cycloidal and homogeneous spin states, via magneto-electric interactions.

• 한국세라믹학회지
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• 제30권7호
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• pp.578-588
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• 1993

Highly c-axis oriented ferroelectric PbTiO3 thin films were deposited on MgO single crystal substrates by RF magnetron sputtering. We have studied the effects of substrate temperature, RF input power, gas comosition, gas pressure and deposition rate on the chemical and structural characteristics of PbTiO3 thin films. The epitaxy relationship of c-axis oriented films was found to be PbTiO3{100}//MgO(100) and their microstructures were highly mosaic. It was found that the most important parameter to achieve epitaxial PbTiO3 films was the substrate temperature. The activation energy for the epitaxy formation was about 0.92eV. Lower gas pressure and RF input power were favorable for the formation of epitaxial c-axis orientation. It was also found that the optimum oxygen content in Ar gas was 10% to obtain the stoichiometric PbTiO3 composition.

• 한국세라믹학회지
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• 제31권11호
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• pp.1315-1322
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• 1994

In this study, stable PbTiO3 coating solution was prepared using diethanolamine(DEA) complexing agent and deposited on indium-tin oxide(ITO) coated glass substrate. Prepared thin films were dense and crack-free. Perovskite-type PbTiO3 thin films could be obtained above 50$0^{\circ}C$, while the films heat-treated above $650^{\circ}C$ showed undesired properties due to interface reactions between films and substrates and warpage phenomena of substrates. Measured maximum dielectric constant and loss tangent were found to be 144 and 0.0163 at 1 kHz, 55$0^{\circ}C$ heat-treatment, respectively.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 하계학술대회 논문집
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• pp.371-374
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• 2002

Bismuth lanthanum titanate thin films with excess Bi contents were prepared onto Pt/Ti/$SiO_2$/Si substrate by metalorganic decomposition (MOD) technique. The structure and morphology of the films were analyzed using X-ray diffraction (XRD) and atomic force microscopy (AFM), respectively. From the XRD analysis, BLT thin films show polycrystalline structure and the layered-perovskite phase was obtained over 10% excess of Bi contents. As a result of ferroelectric characteristics related to the Bi content of the BLT thin film, the remanent polarization and dielectric constant decreased with increasing over Bi content of 10 % excess. The BLT film with Bi content of 10% excess was measured to have a dielectric constant of n9 and dielectric loss of 1.85[%]. The BLT thin films showed little polarization fatigue test up to 3.5 x $10^{9}$ bipolar switching cycling.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 추계학술대회 논문집 Vol.18
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• pp.11-12
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• 2005

[ $Pb(Zr_{0.48}Ti_{0.52})O_3$ ] (PZT) thin films were deposited on Pt(111)/Ti/$SiO_2$/Si substrates by pulsed laser deposition. In order to study the effect of different laser pulse repetition rate on the dielectric and ferroelectric properties of PZT thin films,2 Hz and 5 Hz of laser pulse repetition rate were selected. We compared the results of XRD pattern, dielectric constant and hysteresis characteristics. From the experimental data, we found that the electrical properties of PZT thin films which grown ar 2 Hz of laser pulse repetition rate were better than those which grown at 5 Hz of laser pulse repetition rate.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1999년도 춘계학술대회 논문집
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• pp.109-112
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• 1999

The PZT(10/90)/(90/17) heterolayered thin films were fabricated by the spin-coaling on the Pt/Ti/SiO$_2$/Si substrate using the PZT(10/90) and PZT(70/10) metal alkoxide solutions. The effect of heterolayered thin films on the ferroelectrics and electrical properties have been investigated. The lower PZT layers provided the nucleation site for the formation of a perovskite phase of the upper PZT films. Dielectric constant increased with increasing the number of coatings, and it was about 569.9 at PZT-6 heterolayered films.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 제37회 하계학술대회 논문집 C
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• pp.1394-1395
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• 2006

$(Na_{0.5}LaK_{0.5})NbO_3$ (NKN) thin films were fabricated by the alkoxide-based MOD method. NKN stock solutions were made spin-coated onto the Pt/Ti/$SiO_2$/Si substrate. The structural properties of the NKN thin films examined by x-ray diffraction. The perovskite phase was obtained as a function of the annealing temperature from $550^{\circ}C$ to $700^{\circ}C$ for 1h. The crystallinity and grain size of the NKN thin films increased with increasing annealing temperature. The dielectric constants and loss of the NKN thin films annealed at $650^{\circ}C$ ($t_{eq}$=2.35 nm) showed 323 and 0.025.

• 센서학회지
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• 제11권1호
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• pp.48-53
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• 2002

강유전 물질인 $Pb_{0.99}[(Zr_{0.6}Sn_{0.4})_{1-x}Ti_x]_{0.98}Nb_{0.02}O_3$(PNZST) 박막을 10 mole%의 과잉 PbO가 첨가된 타겟을 이용하여 $La_{0.5}Sr_{0.5}CoO_3$(LSCO)/Pt/Ti/$SiO_2$/Si 기판상에 RF 마그네트론 스퍼터링 방법으로 증착하였다. Ti의 조성비를 변화시키면서 증착된 박막에 대하여 그 결정성과 전기적 특성을 조사하였다. 80 W의 RF 전력, $500^{\circ}C$의 기판온도에서 증착한 후, $650^{\circ}C$, 공기중에서 10초 동안 급속 열처리된 박막이 가장 우수한 페로브스카이트상으로 결정화되었다. 또한. Ti의 조성비가 10 mole%를 가지는 PNZST이 가장 우수한 결정성과 강유전 특성을 나타내었다. 이러한 박막으로 제작된 PNZST 커패시터는 약 $20\;{\mu}C/cm^2$정도의 잔류분극과 약 50 kV/cm 정도의 항전계를 나타내었으며, $2.2{\times}10^9$의 스위칭 후에도 잔류분극의 감소는 10% 미만이었다.

• 한국자기학회:학술대회 개요집
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• 한국자기학회 2003년도 somma/kms meeting
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• pp.204-204
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• 2003