• 제목/요약/키워드: $SrTiO_3$films

검색결과 477건 처리시간 0.027초

무선랜 대역용 Ba0.5Sr0.5TiO3 박막을 이용한 가변 대역 통과 여파기 (Tunable Band-pass Filters using Ba0.5Sr0.5TiO3 Thin Films for Wireless LAN Application)

  • Kim, Ki-Byoung;Yun, Tae-Soon;Lee, Jong-Chul;Kim, Il-Doo;Lim, Mi-Hwa;Kim, Ho-Gi;Kim, Jong-Heon;Lee, Byungje;Kim, Na-Young
    • 한국전자파학회논문지
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    • 제13권8호
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    • pp.819-826
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    • 2002
  • 본 논문은 $Ba_{0.5}$Sr$_{0.5}$TiO$_3$(BST) 박막을 이용한 대역 통과 여파기를 설계, 제작한 것으로 마이크로스트립 과 코플래너 웨이브가이드(CPW), CBCPW 전송 선로 구조에서 각 구조의 여파기 특성을 비교하였다. 제작된 여파기는 전압 0V 인가시 각각 6.4 GHz, 6.14 GHz, 6.04 GHz의 중심 주파수와 6 dB, 4.41 dB, 5.41 dB의 삽입 손실이 측정되었으며, 40V 인가시 중심 주파수 6.61 GHz, 6.31 GHz, 6.21 GHz와 삽입 손실 7.33 dB, 5.83 dB, 6.83 dB로 나타났다. 본 논문에서 제작된 각각의 대역 통과 야파기는 가변 범위가 약 3 % - 8 %이며, 무선랜 대역에 응용할 수 있도록 설계 및 제작되었다.다.

Y$Ba_{2}$$Cu_{3}$$O_{7-\delta}$ coated conductors의 응용을 위한 단일완충층에 대한 연구 (A study on the single buffer layers for the application of $YBa_{2}$$Cu_{3}$$O_{7-\delta}$ coated conductors)

  • 정준기;최수정;고락길;;신기철;박유미;하홍수;김호섭;송규정
    • 한국초전도저온공학회:학술대회논문집
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    • 한국초전도저온공학회 2003년도 추계학술대회 논문집
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    • pp.120-122
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    • 2003
  • BaZrO$_3$and SrTiO$_3$(STO) thin films were Pulsed laser deposited on biaxially textured Ni and Ni-W alloy substrates to be used as single buffer layer for coated conductor. The texture of the films were analysed using the GADDS (general area detector diffraction system). Both films deposited on the metal tape were strongly (001) oriented, and in-plane textured (Δø (BZO) =9$^{\circ}$, Δø (STO) = 10$^{\circ}$).

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The Electric Conductivity $SrBi_2Ta_2O_9$ Capacitors using Rf Magnetron Sputtering Technique

  • Cho, C.N.;Shin, C.G.;Song, M.J.;Choi, W.S.;Park, G.H.;So, B.M.;Kim, C.H.
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2008년도 춘계학술대회 논문집
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    • pp.3-5
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    • 2008
  • The $SrBi_2Ta_2O_9$ thin films are deposited on Pt-coated electrode(Pt/$TiO_2/SiO_2$/Si) using RF magnetron sputtering method. The ferroelectric properties of SBT capacitors with annealing temperatures were studied. Through the x-ray diffraction analysis and the scanning electron microscopy (SEM), it could be observed that crystallization of the SBT thin film started around $650^{\circ}C$ and complete crystallization was accomplished around $750^{\circ}C$ and grains grew from a small spheric form to rod-like. For the leakage current density of the SBT capacitor depending upon various annealing atmospheres, capacitor annealed in the oxygen atmosphere showed the most excellent characteristic, and they were respectively about $2.13\times10^{-9}[A/cm^2]$ at 5V and 340.

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불순물 첨가에 따른 VO2 후막 급변온도센서의 온도-저항 특성 (Temperature vs. Resistance Characteristics by Dopants of VO2 Thick-Film Critical Temperature Sensors)

  • 최정범;강종윤;윤석진;유광수
    • 센서학회지
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    • 제23권5호
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    • pp.337-341
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    • 2014
  • For various additives doped-$VO_2$ critical temperature sensors using the nature of semiconductor to metal transition, the crystallinity, microstructure, and temperature vs. resistance characteristics were systematically investigated. As a starting material of $VO_2$ sensor, vanadium pentoxide ($V_2O_5$) powders were used, and CaO, SrO, $Bi_2O_3$, $TiO_2$, and PbO dopants were used, respectively. The $V_2O_5$ powders with dopants were mixed with a vehicle to form paste. This paste was silk screen-printed on $Al_2O_3$ substrates and then $V_2O_5$-based thick films were heat-treated at $500^{\circ}C$ for 2 hours in $N_2$ gas atmosphere for the reduction to $VO_2$. From X-ray diffraction analysis, $VO_2$ phases for pure $VO_2$, and CaO and SrO-doped $VO_2$ thick films were confirmed and their grain sizes were 0.57 to $0.59{\mu}m$. The on/off resistance ratio of the $VO_2$ sensor in phase transition temperature range was $5.3{\times}10^3$ and that of the 0.5 wt.% CaO-doped $VO_2$ sensor was $5.46{\times}10^3$. The presented critical temperature sensors could be commercialized for fire-protection and control systems.

Ferroelectric $SrBi_2Ta_2O_9$ Thin Films by Liquid-Delivery Metalorganic Chemical Vapor Deposition using $Sr[Ta(OEt)_5(dmae)]_2$ and $Bi(C_6H_5)_3$

  • Shin, Wonng-Chul;Choi, Kyu-Jeong;Park, Chong-Man;Yoon, Soon-Gil
    • The Korean Journal of Ceramics
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    • 제6권3호
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    • pp.219-223
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    • 2000
  • The ferroelectric SBT films were deposited on Pt/Ti/SiO$_2$/Si substrates by liquid injection metalorganic chemical vapor deposition (MOCVD) with single-mixture solution of Sr[Ta(OEt)$_5$(dmae)]$_2$and Bi(C$_6$ 6/H$_5$)$_3$. The Sr/Ta and Bi/Ta ratio in SBT films depended on deposition temperature and mol ratio of precursor in the single-mixture solution. At the substrate temperature of 40$0^{\circ}C$, Sr/Ta and Bi/Ta ratio were close to 0.4 and 1 at precursor mol ratio of 0.5~1.0, respectively. As-deposited film was amorphous. However, after annealing at 75$0^{\circ}C$ for 30 min in oxygen atmosphere, the diffraction patterns indicated polycrystalline SBT phase. The remanent polarization (Pr) and coercive field (Ec) of SBT film annealed at 75$0^{\circ}C$ were 4.7$\mu$C/$\textrm{cm}^2$ and 115.7kV/cm at an applied voltage of 5V, respectively. The SBT films annealed at 75$0^{\circ}C$ showed practically no polarization fatigue up to 10$^10$ switching cycles.

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펄스레이저증착법을 이용한 $\textrm{LaAlO}_3$ 박막의 Molecular Beam Epitaxy 성장 (Molecular Beam Epitaxy Grouth of $\textrm{LaAlO}_3$ Thin Film by a Pulsed laser Deposition Technique)

  • 김인선;허남회;박용기
    • 한국재료학회지
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    • 제9권1호
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    • pp.25-29
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    • 1999
  • We have developed a laser molecular beam epitaxy system for the layer-by-layer growth of oxide thin films. Using this system, we could grow and control oxide thin films of LaAlO$_3$in a molecular layer epitaxy mode on the atomically flat SrTiO$_3$ substrate with a LaAlO$_3$single crystal target. Very clear RHEED oscillations were observed during to growth of a LaAlO$_3$ film for a long period under the optimized conditions of substrate temperature at $650^{\circ}C$, oxygen pressure at 1$\times$10\ulcorner torr, and an incident laser fluence of 4.6J/$\textrm{cm}^2$. The height of mono-layer-LaAlO$_3$ film grown during one period of RHEED intensity oscillation was 3.8$\AA$.

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서미스터 소자로의 응용을 위한 솔-젤법으로 제작한 (La0.7Sr0.3)(Mn1-xFex)O3 박막의 구조적, 전기적 특성 (Structural and Electrical Properties of (La0.7Sr0.3)(Mn1-xFex)O3 Thin Films Prepared by Sol-Gel Method for Thermistor Devices)

  • 육지수;이삼행;이명규;박주석;김영곤;이성갑
    • 한국전기전자재료학회논문지
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    • 제37권2호
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    • pp.164-168
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    • 2024
  • (La0.7Sr0.3)(Mn1-xFex)O3 (LSMFO) (x = 0.03, 0.06, 0.09, 0.12) precursor solution are prepared by sol-gel method. LSMFO thin films are fabricated by the spin-coating method on Pt/Ti/SiO2/Si substrate, and the sintering temperature and time are 800℃ and 1 hr, respectively. The average thickness of the 6-times coated LSMFO films is about 181 to 190 nm and average grain size is about 18 to 20 nm. As the amount of Fe added in the LSMFO thin film increased, the resistivity decreased, and the TCR and B25/65-value increased. Electrical resistivity, TCR and B25/65-value of the (La0.7Sr0.3)(Mn0.88Fe0.12)O3 thin film are 0.0136 mΩ-cm, 0.358%/℃, and 328 K at room temperature, respectively. The resistivity properties of LSMFO thin films matched well with Mott's VRH model.

증착온도에 따른 SBN 박막의 미세구조 및 특성 (Microstructure and Properties of SBN Thin film with Deposition Temperature)

  • 김진사;최운식;김충혁
    • 전기학회논문지
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    • 제58권3호
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    • pp.544-547
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    • 2009
  • The $Sr_{0.7}Bi_{2.3}Nb_{2}O_{9}$(SBN) thin films are deposited on Pt-coated electrode(Pt/Ti/$SiO_2$/Si) using RF sputtering method at various deposition temperature. The optimum conditions of RF power and Ar/$O_2$ ratio were 60[W] and 70/30, respectively. Deposition rate of SBN thin films was about 4.17[nm/min]. The crystallinity of SBN thin films were increased with increase of deposition temperature in the temperature range of $100{\sim}400[^{\circ}C]$, the surface rougness showed about 4.33[nm]. The capacitance of SBN thin films were increased with the increase of deposition temperature.

열처리에 따른 BST 박막의 특성에 관한 연구 (Study on Post Annealing Dependence of BST Thin Films)

  • 최명률;박인철;권학용;손재구;김홍배
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2005년도 하계학술대회 논문집 Vol.6
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    • pp.197-198
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    • 2005
  • 본 논문에서는 p-type (100)Si. (100)MgO 그리고 MgO/Si 기판 위에 RF Magnetron sputtering 법으로 $Ba_{0.5}Sr_{0.5}TiO_3$(BST) 박막을 증착 후 $600^{\circ}C$ 의 질소분위에서 RTA(Rapid Thermal Annealing)를 이용한 1 분간의 고온 급속열처리를 하였다. XRD 측정결과 모든 기판에서 (110) $Ba_{0.5}Sr_{0.5}TiO_3$의 주피크가 관찰되어졌고, 열처리 후 피크 세기가 증가함을 확인할 수 있었다. C-V 특성에서 각각의 기판에서 측정된 커패시턴스 값으로 계산된 유전율은 120(bare Si), 305(MgO/Si) 그리고 310(MgO)이었다. 누설 전류 특성에서는 150KV/cm이내의 인가전계에서 0.1$uA/cm^2$이하의 안정된 누설전류값을 보여주었다. 결론적으로 MgO 버퍼층을 이용한 기판이 BST 박막의 증착을 위한 기판으로써 효과적임을 알 수 있었다.

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