• 한국전기전자재료학회논문지
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• 제13권7호
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• pp.592-597
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• 2000

In this study (B $a_{0.5}$/S $r_{0.5}$)Ti $O_3$[BST(50/50)] ceramic thin films were prepared by the Sol-Gel method BST(50/50) stock solution was made and spin-coated on the Indium Tin Oxide(ITO)/glass substrate at 4000 rpm for 30 seconds. The coated films were dried at 35$0^{\circ}C$ for 10 minutes and annealed at 650~75$0^{\circ}C$ for 1 hour. The microstructural properties of the BST(50/50) thin film were studied by the XRD and AFM. The ferroelectric perovskite phase was formed at the annealing condition of 75$0^{\circ}C$ for 1 hour. Dielectric constant and loss of this thin were 370, 3.7% at room temperature respectively. The polarization switching voltage showed the good value of 3V. The leakage current density of the BST(50/50) thin film was 10$^{-7A}$c $m^2$with applied voltage of 1.5V. BST(50/50) thin film capacitors having good dielectric and electrical properties are expecting for the application to the dielectric material of DRAM.RAM.M.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 하계학술대회 논문집 Vol.5 No.2
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• pp.582-585
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• 2004

Pb0.5Sr0.5TiO3 (PST) thin films were fabricated by the alkoxide-based sol-gel process using spin-coating method on Pt/Ti/SiO2/Si substrate. The PST films annealed from 500C to 650C for 1h show a perovskite phase and dense microstructure with a smooth surface. The grain size and dielectric constant of PST films increases with the increase in annealing temperature, which reduces the SiO2 equivalent thickness of the PST film. The crystallinity or internal strain in the PST thin films analyzed from the diffraction-peak widths correlate well with the decrease in the dielectric losses. The dielectric constants and dielectric loss (%) of the PST films annealed at 650c (teq : 0.89 nm) were 549 and 0.21%, respectively.

• 공업화학
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• 제8권4호
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• pp.589-594
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• 1997

화학증착법을 통하여 $650^{\circ}C$의 증착온도와 0.0126Torr의 산소분압인 증착조건에서 원료물질로 $\beta$-diketonates 킬레이트 화합물을 사용하여 Si(111) 및 $SrTiO_3(100)$ 기판에 $YBa_2Cu_3O_y$ 고온 초전도 박막을 제조하였다. $SrTiO_3(100)$기판에서 제조된 박막의 $T_{c,onset}$과 $T_{c.0}$는 각각 91K와 87K로 나타났다. 또한, Si(111)기판에서 제조된 박막의 $T_{c,onset}$은 91K였지만 $T_{c.0}$는 액체질소 비등점(77.3K)에서는 보이지 않았다. $SrTiO_3(100)$에 증착된 초전도 박막은 치밀하고 2차원적으로 배열된 미세구조를 갖고 있는 반면, Si(111)에 증착된 초전도 박막은 상대적으로 기공이 많으며 무질서한 미세구조를 형성하였다.

• 한국재료학회:학술대회논문집
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• 한국재료학회 1996년도 재료학회 추계학술발표회
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• pp.51-51
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• 1996

• The Korean Journal of Ceramics
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• 제1권4호
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• pp.204-208
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• 1995

The microstructure and electrical propetries were investigated for polycrystalline $Ba^{1-x}Sr_xTiO_3$(BST) thin films deposited on Pt/Ti/$SiO_2$(PTSS) and Pt/MgO(PM) substrates by metalorganic chemical vapor deposition (MOCVD). BST films on PTSS have coulmnar and porous structures, while on PM have an equiaxied and dense structure. The dielectric constant and a dissipation factor of BST films on PTSS and 20 fC/$\mu \textrm{cm}^3$ on PTSS and 12fC/$\mu \textrm{cm}^2$ on PM was obtained at an applied electric field of 0.06 MV/cm. Leakage current density of BST films on PM was smaller than that on PTSS. The leakage current density level was about $8\times10^{-8}A/\textrm{cm}^2$ at 0.04MV/cm.

• 한국재료학회지
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• 제33권6호
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• pp.229-235
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• 2023

An all-perovskite oxide heterostructure composed of SrSnO₃/Nb-doped SrTiO₃ was fabricated using the pulsed laser deposition method. In-plane and out-of-plane structural characterization of the fabricated films were analyzed by x-ray diffraction with θ-2θ scans and φ scans. X-ray photoelectron spectroscopy measurement was performed to check the film's composition. The electrical transport characteristic of the heterostructure was determined by applying a pulsed dc bias across the interface. Unusual transport properties of the interface between the SrSnO₃ and Nb-doped SrTiO₃ were investigated at temperatures from 100 to 300 K. A diodelike rectifying behavior was observed in the temperature-dependent current-voltage (IV) measurements. The forward current showed the typical IV characteristics of p-n junctions or Schottky diodes, and were perfectly fitted using the thermionic emission model. Two regions with different transport mechanism were detected, and the boundary curve was expressed by ln I = -1.28V - 13. Under reverse bias, however, the temperature- dependent IV curves revealed an unusual increase in the reverse-bias current with decreasing temperature, indicating tunneling effects at the interface. The Poole-Frenkel emission was used to explain this electrical transport mechanism under the reverse voltages.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 추계학술대회 논문집 Vol.21
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• pp.165-166
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• 2008

$(Ba_{0.6},Sr_{0.3},Ca_{0.1})TiO_3$ powders, which were prepared by sol-gel method using a solution of Ba-acetate, Sr-acetate and Ca-acetate and Ti iso-propoxide, were mixed with organic vehicle and the BSCT thick films were fabricated by the screen-printing techniques on high purity alumina substrates. The structural and dielectirc properties were investigated for various $Pr_2O_3$ and $Y_2O_3$doping contents. As a result of thermal analysis of $(Ba_{0.6},Sr_{0.3},Ca_{0.1})TiO_3$ powders, the exothermic peak was observed at around $670^{\circ}C$ due to the formation of the polycrystalline perovskite phase. All BSCT thick films, sintered at $1420^{\circ}C$ for 2h, showed the typical XRD patterns of perovskite polycrystalline structure. The average grain size of the specimens decreased with amount of $Pr_2O_3$ and $Y_2O_3$ contents.

• 한국세라믹학회:학술대회논문집
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• 한국세라믹학회 2000년도 춘계총회,특별강연,심포지움,연구발표회
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• pp.129.1-129.1
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• 2000

• 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.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 추계학술대회 논문집 Vol.15
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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.