• Title/Summary/Keyword: $TiO_2-V_2O_5$ Thin Films

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Electrical Properties of $V_{1.85}W_{0.15}O_5$ Thin Films with Thickness (두께에 따른 $V_{1.85}W_{0.15}O_5$ 박막의 전기적 특성)

  • Lee, Seung-Hwan;Lee, Sung-Gap;Bae, Seon-Gi;Lee, Young-Hie
    • Proceedings of the KIEE Conference
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    • 2008.10a
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    • pp.121-122
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    • 2008
  • The films of the vanadium tungsten oxide, $V_{1.85}W_{0.15}O_5$, were grown on Pt/Ti/$SiO_2$/Si substrate by RF sputtering method. It was found that film crystallinity, dielectric properties, and TCR properties were strongly dependent upon the thin film thickness. As increasing of $V_{1.85}W_{0.15}O_5$ thickness, the grain size, morphology, and crystallinity increased. The dielectric constants of $V_{1.85}W_{0.15}O_5$ thin films deposited at 150nm were 71.11, with a dielectric loss of 0.015, respectively. Also, The $V_{1.85}W_{0.15}O_5$ thin films showed good TCR values of -3.45%/K.

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Effects of Annealing Conditions on the Properties of Bi1-xLaxTi3O12 Thin Films (열처리 조건이 Bi1-xLaxTi3O12 (x=0.75) 박막의 특성에 미치는 효과)

  • Park Moon Heum;Kim Sang Su;Gang Min Ju;Ha Tae Gon
    • Korean Journal of Materials Research
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    • v.14 no.10
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    • pp.701-706
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    • 2004
  • Bismuth layered structure ferroelectric thin films, La-substituted $Bi_{4}Ti_{3}O_{12}$ ($Bi_{1-x}La_{x}Ti_{3}O_{12}$, x=0.75, BLT) were prepared on the $Pt(111)/Ti/SiO_2/Si(100)$ substrates by a sol-gel spin coating process. The thin films were annealed in various conditions, i.e., oxygen, nitrogen and vacuum atmospheres for various annealing time. We investigated the annealing condition effects on the grain orientation and ferroelectric properties. The measured XRD patterns revealed that the BLT thin films showed only $Bi_{4}Ti_{3}O_{12}$-type phase with random orientation. $La^{3+}$ ion substitution for $Bi^{3+}$ ion in perovskite layers of $Bi_{4}Ti_{3}O_{12}$ decreased the degree of c-axis orientation and increased the remanent polarization ($2P_{r}$). The remanent polarization ($2P_{r}$) and the coercive field ($2E_{c}$) of the BLT thin film annealed at $650^{\circ}C$ for 5 min in oxygen atmosphere were $87{\mu}C/cm^2$ and 182 kV/cm, respectively, at an applied electric field of 240 kV/cm. For all of the BLT thin films annealed in various conditions, the fatigue resistance was shown. The improvement of ferroelectric properties with La substitution in $Bi_{4}Ti_{3}O_{12}$ could be attributed to the changes in space charge densities and grain orientation in the thin film.

Effect of RTA on the interfacial Properties of Top Electrodes on $(Ba_{0.5}Sr_{0.5})TiO_3$ ($(Ba_{0.5}Sr_{0.5})TiO_3$ 박막의 상부전극 RTA에 따른 계면 특성 변화)

  • Jeon, Jang-Bae;Kim, Dyeok-Kyu;So, Soon-Jin;Park, Choon-Bae
    • Proceedings of the KIEE Conference
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    • 1998.11c
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    • pp.740-742
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    • 1998
  • In this paper, we described the effect of rapid thermal annealing on the electrical properties of interfacial layer between various top electrodes and $(Ba_{0.5}Sr_{0.5})TiO_3$ thin films. BST thin films were fabricated on Pt/TiN/$SiO_2$/Si substrate by RF magnetron sputtering technique. AI, Ag, and Cu films for the formation of top electrode were deposited on BST thin films by thermal evaporator. Top electrodes/BST/Pt capacitor annealed with rapid thermal annealing at various temperature. In $(Ba_{0.5}Sr_{0.5})TiO_3$ thin films with Cu top electrode annealed at $500^{\circ}C$, the dielectric constant was measured to the value of 366 at 1.2 [kHz] and the leakage current was obtained to the value of $5.85{\times}10^{-7}\;[A/cm^2}$ at the forward bias of 2 [V].

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The Preparation and Characterization of BNdT Thin Films by MOD Process (MOD법을 이용한 BNdT박막의 제조 및 특성 연구)

  • Kim, Ki-Beom;Jang, Gun-Eik
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2002.07b
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    • pp.861-864
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    • 2002
  • Ferroelectric $Bi_{4-x}Nd_xTi_3O_{12}$(BNdT) thin films with the composition(x=0.75) were prepared on pt/Ti/$SiO_2$/Si(100) substrate by metal-organic deposition. The electrical and structural characteristics of BNdT thin films were investigated to develop ferroelectric thin films for capacitor layers of FRAM. After spin coating, thin films were annealed at $650^{\circ}C$ for 1hour in oxygen atmosphere. Scanning electron micrographs showed uniform surfaces composed of rod-like grains. The $Bi_{4-x}Nd_xTi_3O_{12}$(X=0.75) thin film capacitors with a Pt top electrode showed better ferroelectric properties. At the applied voltage of 5V, the dielectric constant$(\varepsilon_r)$, dissipation factor$(tan{\delta})$, remanent polarization(2Pr) and nonvolatile swiching charge of the $Bi_{4-x}Nd_xTi_3O_{12}$(x=0.75)thin films were about 346.7, 0.095, $56{\mu}C/cm^2$ and $38{\mu}C/cm^2$ respectively. Also the capacitor did not show any significant fatigue up to $8{\times}10^{10}$ read/write switching cycles at a frequency of 1MHz.

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Fabrication and Characterization of Ferroelectric $(Bi,Sm)_4Ti_3O_{12}$ Thin Films Prepared by Chemical Solution Deposition

  • Kang, Dong-Kyun
    • Proceedings of the Korean Society Of Semiconductor Equipment Technology
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    • 2006.10a
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    • pp.170-173
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    • 2006
  • Ferroelectric $Bi_{3.35}Sm_{0.65}Ti_3O_{12}(BST)$ thin films were deposited on $Pt(111)/Ti/SiO_2/Si(100)$ substrates by a sol-gel spin-coating process. In this experiments, $Bi(TMHD)_3$, $Sm_5(O^iPr)_{13}$, $Ti(O^iPr)_4$ were used as precursors, which were dissolved in 2-methoxyethanol. Thereafter, the thin films with the thickness, of 240nm were annealed from 600 to $720^{\circ}C$ in oxygen atmosphere for 1 hr, and post-annealed in oxygen atmosphere for 1 hr after deposition of Pt electrode to enhance the electrical properties. The remanent polarization and coercive voltage of the BST thin films annealed at $720^{\circ}C$ were $19.48\;{\mu}C/cm^2$ and 3.40 V, respectively, and a fatigue-free characteristics. As a result, Sm-substituted bismuth titanate films with good ferroelectric properties and excellent fatigue resistance are useful candidates for ferroelectric memory applications.

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Electrical properties of $SrTiO_3$ thin films deposited at low temperatures by RF magnetron sputtering (RF 마그네트론 스퍼터링에 의해 저온 증착한 $SrTiO_3$ 박막의 전기적 특성)

  • 김동식;이재신
    • Journal of the Korean Vacuum Society
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    • v.5 no.4
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    • pp.359-364
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    • 1996
  • $SrTiO_3$ thin films were deposited on Pt/Ti/$SiO_2$/Si substrates at low temperatures below $300^{\circ}C$ by r.f. magnetron sputtering. The materials and the electrical properties of the deposited films were investigated with controlling deposition parameters such as substrate temperature(T_s) and positive substrate d.c. bias voltage. Stoichiometric $SrTiO_3$ films were obtained at Ts of $300^{\circ}C$, but Sr content in the film was less than that of a target when Ts was lower than $300^{\circ}C$, resulting in poor electrical properties. By introducing a positive substrate d.c. bias during deposition, the crystallinity and the dielectric properties of the films were markedly improved. 400 nm thick $SrTiO_3$, films deposited at $300^{\circ}C$ with a positive substrate d.c. bias of 20V showed a columnar structure with <211> crystallographic direction and a dielectric constant of 98.

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Structural and Dielectric Properties of Pb[(Zr,Sn)Ti]NbO3 Thin Films Deposited by Radio Frequency Magnetron Sputtering

  • Choi, Woo-Chang
    • Transactions on Electrical and Electronic Materials
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    • v.11 no.4
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    • pp.182-185
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    • 2010
  • $Pb_{0.99}[(Zr_{0.6}Sn_{0.4})_{0.9}Ti_{0.1}]_{0.98}Nb_{0.02}O_3$ (PNZST) thin films were deposited by radio frequency magnetron sputtering on a $(La_{0.5}Sr_{0.5})CoO_3$ (LSCO)/Pt/Ti/$SiO_2$/Si substrate using a PNZST target with an excess PbO of 10 mole%. The thin films deposited at the substrate temperature of $500^{\circ}C$ crystallized to a perovskite phase after rapid thermal annealing (RTA). The thin films, which annealed at $650^{\circ}C$ for 10 seconds in air, exhibited good crystal structures and ferroelectric properties. The remanent polarization and coercive field of the fabricated PNZST capacitor were approximately $20uC/cm^2$ and 50 kV/cm, respectively. The reduction of the polarization after $2.2\;{\times}\;10^9$ switching cycles was less than 10%.

Microstructure and Electric Properties of Ferroelectric SrBi$_2$Ta$_2$O$_9$ Thin Films Deposited by Modified Rf Magnetron Sputtering Technique (Modified Rf Magnetron Sputtering에 의해 Pt/Ti/SiO$_2$/Si 기판위에 제조된 강유전체 SrBi$_2$Ta$_2$O$_9$ 박막의 미세구조 및 전기적 특성 연구)

  • 양철훈;윤순길
    • Journal of the Korean Ceramic Society
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    • v.35 no.5
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    • pp.472-478
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    • 1998
  • Ferroelectric SrBi2Ta2O9(SBT) films were deposited on Pt/Ti/SiO2/Si substrates at 50$0^{\circ}C$ using a sintered SBT target Bi and Ta targets by modified rf magnetron sputtering and then were annealed at 80$0^{\circ}C$ for 10min in oxygen ambinet(760 torr) The composition of the SBT films could be easily controlled using the mul-ti-targets. The film composition of {{{{ {Sr }_{0.8 } {Bi }_{2.9 } {Ta}_{2.0 } {O }_{9 } }} was obtained with SBTd sputtering power of 100 W Bi of 25W and Ta of 10 W. A 250nm thick SBT films exhibited a dense and uniform microstructure and showed the remanent polarization(Pr) of 14.4 $\mu$C/cm2 and the coercive field({{{{ {E }_{c } }})of 60 kV/cm at applied voltage of 5 V. The SBT films show practically no polarization fatigue up to {{{{ {10 }_{10 } }} cycles under 5V bipolar pulse. The retention characteristics of the SBT films looked very promising and the leakage current density of the SBT films was about 1.23$\times${{{{ {10 }^{-7 } }}A/c{{{{ {m }^{2 } }} at 120kV/cm.

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An effect of component layers on the phases and dielectric properties in $PbTiO_3$ thin films prepared from multilayer structure (다층구조박막으로부터 $PbTiO_3$ 박막 제조시 요소층이 상형성 및 유전특성에 미치는 영향)

  • Do-Won Seo;Song-Min Nam;Duck-Kyun Choi
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.4 no.4
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    • pp.378-387
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    • 1994
  • To improve the properties of $PbTiO_3$ thin films successfully grown by thermal diffusion of 3 component layers of $Ti0_2/Pb/TiO_2(900{\AA}/900{\AA}/900{\AA})$ in preceding research, 3, 5, 7, 9, and 11 multilayer structures $(TiO_2/Pb/.../Tio_2)$ with thinner component layer of $200~300 {\AA}$ thick were deposited on Si substrate by RF sputtering, which were followed by RTA to form $PbTiO_3$ thin films. As a result, $PbTiO_3$ single phase was formed above $500^{\circ}C$. When the thickness of component layer reduced and the number of component layers increased, suppression of Pb-silicate and voids formation resulted in relatively sharp interfaces and the film composition became more homogeneous. Relative dielectric constants in MIM structure were independent of the annealing condition, but they increased with increasing thickness of the $PbTiO_3$ thin films. The maximum breakdown field in MIS structure reached 150kV/cm.

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Low Temperature Sintering Process of Sol-gel Derived Ferroelectric Sr0.9Bi2.1Ta1.8Nb0.2O9 Thin films (Sol-gel 법으로 제조된 강유전체 Sr0.9Bi2.1Ta1.8Nb0.2O9 박막의 저온결정화 공정)

  • 김영준;김병호
    • Journal of the Korean Ceramic Society
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    • v.40 no.3
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    • pp.279-285
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    • 2003
  • Ferroelectric S $r_{0.9}$B $i_{2.1}$T $a_{1.8}$N $b_{0.2}$ thin films with 200 nm thicknesses were deposited on Pt/Ti $O_2$/ $SiO_2$/Si Substrates by a sol-gel method. In these experiments, Sr(O $C_2$ $H_{5}$)$_2$, Bi(TMHD)$_3$, Ta(O $C_2$ $H_{5}$)$_{5}$ and Nb(O $C_2$ $H_{5}$)$_{5}$ were used as precursors, which were dissolved in 2-methoxyethanol. After UV-irradiation and RTA processes, the remanent polarization value (2 $P_{r}$) of SBTN thin films with annealed at $650^{\circ}C$ was 8.49 and 11.94 $\mu$C/$\textrm{cm}^2$ at 3 V and 5 V, respectively.