• Title/Summary/Keyword: Low density ceramics

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Effect of RTA Treatment on $LiNbO_3$ MFS Memory Capacitors

  • Park, Seok-Won;Park, Yu-Shin;Lim, Dong-Gun;Moon, Sang-Il;Kim, Sung-Hoon;Jang, Bum-Sik;Junsin Yi
    • The Korean Journal of Ceramics
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    • v.6 no.2
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    • pp.138-142
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    • 2000
  • Thin film $LiNbO_3$MFS (metal-ferroelectric-semiconductor) capacitor showed improved characteristics such as low interface trap density, low interaction with Si substrate, and large remanent polarization. This paper reports ferroelectric $LiNbO_3$thin films grown directly on p-type Si (100) substrates by 13.56 MHz RF magnetron sputtering system for FRAM (ferroelectric random access memory) applications. RTA (rapid thermal anneal) treatment was performed for as-deposited films in an oxygen atmosphere at $600^{\circ}C$ for 60sec. We learned from X-ray diffraction that the RTA treated films were changed from amorphous to poly-crystalline $LiNbO_3$which exhibited (012), (015), (022), and (023) plane. Low temperature film growth and post RTA treatments improved the leakage current of $LiNbO_3$films while keeping other properties almost as same as high substrate temperature grown samples. The leakage current density of $LiNbO_3$films decreased from $10^{-5}$ to $10^{-7}$A/$\textrm{cm}^2$ after RTA treatment. Breakdown electric field of the films exhibited higher than 500 kV/cm. C-V curves showed the clockwise hysteresis which represents ferroelectric switching characteristics. Calculated dielectric constant of thin film $LiNbO_3$illustrated as high as 27.9. From ferroelectric measurement, the remanent polarization and coercive field were achieved as 1.37 $\muC/\textrm{cm}^2$ and 170 kV/cm, respectively.

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Electrochemical properties of all solid state Li/LiPON/Sn-substituted LiMn2O4 thin film batteries

  • Kong, Woo-Yeon;Yim, Hae-Na;Yoon, Seok-Jin;Nahm, Sahn;Choi, Ji-Won
    • Proceedings of the Korean Vacuum Society Conference
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    • 2011.02a
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    • pp.409-409
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    • 2011
  • All solid-state thin film lithium batteries have many applications in miniaturized devices because of lightweight, long-life, low self-discharge and high energy density. The research of cathode materials for thin film lithium batteries that provide high energy density at fast discharge rates is important to meet the demands for high-power applications. Among cathode materials, lithium manganese oxide materials as spinel-based compounds have been reported to possess specific advantages of high electrochemical potential, high abundant, low cost, and low toxicity. However, the lithium manganese oxide has problem of capacity fade which caused by dissolution of Mn ions during intercalation reaction and phase instability. For this problem, many studies on effect of various transition metals have been reported. In the preliminary study, the Sn-substituted LiMn2O4 thin films prepared by pulsed laser deposition have shown the improvement in discharge capacity and cycleability. In this study, the thin films of LiMn2O4 and LiSn0.0125Mn1.975O4 prepared by RF magnetron sputtering were studied with effect of deposition parameters on the phase, surface morphology and electrochemical property. And, all solid-state thin film batteries comprised of a lithium anode, lithium phosphorus oxy-nitride (LiPON) solid electrolyte and LiMn2O4-based cathode were fabricated, and the electrochemical property was investigated.

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Electrical properties of (Na0.5Bi0.5)(Zr0.75Ti0.25)O3 ceramic

  • Lily, Lily;Yadav, K.L.;Prasad, K.
    • Advances in materials Research
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    • v.2 no.1
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    • pp.1-13
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    • 2013
  • Lead-free compound $(Na_{0.5}Bi_{0.5})(Zr_{0.75}Ti_{0.25})O_3$ was prepared using conventional ceramic technique at $1070^{\circ}C$/4h in air atmosphere. X-ray diffraction analysis showed the formation of single-phase orthorhombic structure. Permittivity data showed low temperature coefficient of capacitance ($T_{CC}{\approx}5%$) up to $100^{\circ}C$. Complex impedance studies indicated the presence of grain boundary effect, non-Debye type dielectric relaxation and evidences of a negative temperature coefficient of resistance. The ac conductivity data were used to evaluate the density of states at Fermi level and apparent activation energy of the compound.

Mechanical and Tribological Properties of $\alpha$-Sialon/SiC Whisker Composites ($\alpha$-Sialon/SiC Whisker 복합재료의 기계적 물성 및 마모 특성 연구)

  • 이병하;김인섭;이경희
    • Journal of the Korean Ceramic Society
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    • v.30 no.10
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    • pp.785-790
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    • 1993
  • Sialon ceramics are presently seen as promising materials with high hardness, strength, fracture toughness and corrosion resistance for friction and wear applications. The objective of present work is to improve of mechanical properties and wear resistance of $\alpha$-Sialon(x=0.4) by addition of SiC whisker. $\alpha$-sialon(x=0.4)/SiC whisker composites were obtained by hot-isostatic pressing at 173$0^{\circ}C$ for 1 hour under 1757Kg/$\textrm{cm}^2$ N2 pressure after pressureless sintering the mixture of Si3N4, Y2O3, AlN at 1780~180$0^{\circ}C$ for 3~5 hours in N2 atmosphere. As the amount of SiC whisker content increased, relative density and hardness were decreased, however fracture toughness, bending strength and tribological properties were improved. Tribological properties of $\alpha$-Sialon/15 vol% SiC whisker composite were improved in spite of its low mechanical properties.

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Characterization of Diamond-like Carbon Films Prepared by Magnetron Plasma Chemical Vapor Deposition

  • Soung Young Kim;Jai Sung Lee;Jin Seok Park
    • The Korean Journal of Ceramics
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    • v.4 no.1
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    • pp.20-24
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    • 1998
  • Thin films of diamond-like carbon(DLC) can be successfully deposited by using a magnetron plasma chemical vapor deposition (CVD) method with an rf(13.56 MHz) plasma of $C_dH_8$. Plasma characteristics are analyzed as a function of the magnetic field. As the magnetic field increases, both electron temperature ($T_e$) and density ($n_e$)increase, but the negative dc self-bias voltage (-$V_{ab}$) decreases, irrespective of gas pressures in the range of 1~7 mTorr. High deposition rates have been obtained even at low gas pressures, which may be attributed to the increased mean free path of electrons in the magentron plasma. Effects of rf power and additive gas on the structural properties of DLC films aer also examined by using various technique namely, TED(transmissio electron diffraction) microanalysis, FTIR, and Raman spectroscopies.

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Influence of $TiO_2$ on Sintering and Microstructure of Magnesia (마그네시아의 소결과 미세구조에 미치는 $TiO_2$의 영향)

  • 이윤복;박홍채;오기동
    • Journal of the Korean Ceramic Society
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    • v.31 no.5
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    • pp.471-476
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    • 1994
  • The influence of TiO2 addition on the sintering and microstructure of magnesia ceramics was studied. An excess amount of TiO2 over the solid solubility limit reacted with magnesia to form Mg2TiO4 compound above 130$0^{\circ}C$. The deviation of lattice parameter of MgO was estimated to be under 0.2% when existence of TiO2 in MgO. The addition of TiO2 markedly promoted the densification of MgO at comparatively low temperature and the sintered density of about 98% of the theorectical was obtained at 150$0^{\circ}C$, 2h. The densification was mainly governed by grain growth of MgO and the effect of Mg2TiO4 existing as a second phase on depression of grain growth of MgO was not exhibited.

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Synthesis and Conductivity Properties of $LaNiO_3$ Ceramic Conductors ($LaNiO_3$전도성 세라믹의 합성과 도전특성)

  • Cho, Jung-Ho;Cho, Joo-Hun;Kim, Kang-Eun;Chung, Su-Tae
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2001.11b
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    • pp.406-409
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    • 2001
  • The conductivity properties and synthesis of $LaNiO_{3}$ ceramics from $La_{1+\delta}NiO_{3}(\delta=-0.06,0,0.06)$ were investigated. A single perovskite phase was realized at $800^{\circ}C$. $La_{2}NiO_{4}$ and other unexpected oxide were observed at $1000^{\circ}C$. The Microstructure was showed clearly that it is a low density porous material. $LaNiO_3$ ceramic showed a metallic conductivity. The conductivity of La rich samples had a higher value than the La poor samples.

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Study on properties of CaO-MgO-$SiO_2$ system glass-ceramic for LTCC (CaO-MgO-$SiO_2$ 계 LTCC glass에 대한 특성 연구)

  • Chang, Myung-Whun;Ma, Won-Chul
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2008.06a
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    • pp.322-322
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    • 2008
  • Low-temperature co-fired ceramics (LTCC) have turned out to be very promising technology in accordance with the rapid developments in semiconductor technology. The demands for compact electrical assemblies, smaller power loss as well as high signal density can be fulfilled by LTCC. And for the multi-layered ceramic devices with embedded passive components such as high dielectric constant decoupling capacitor, LTCC materials require the several conditions to avoid delamination and internal cracks. For the present study, diopside-based glass is chosen as the LTCC substrate material in view of its high coefficient of thermal expansion (CTE). From the experimental resultsn the influence of each element on the CTE change can be revealed.

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Synthesis and Conductivity Properties of LaNiO$_3$ Ceramic Conductors (LaNiO$_3$전도성 세라믹의 합성과 도전특성)

  • 조정호;조주현;김강언;정수태
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2001.11a
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    • pp.406-409
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    • 2001
  • The conductivity properties and synthesis of LaNiO$_3$ ceramics from La$\sub$1+$\delta$/NiO$_3$($\delta$=--0.06, 0, 0.06) were investigated. A single perovskite phase was realized at 800$^{\circ}C$. La$_2$NiO$_4$ and other unexpected oxide were observed at 1000$^{\circ}C$. The Microstructure was showed clearly that it is a low density porous material. LaNiO$_3$ ceramic showed a metallic conductivity. The conductivity of La rich samples had a higher value than the La poor samples.

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Effect of Mn Addition on the Dielectric Loss characteristics of $BaTiO_3$ Ceramics ($BaTiO_3$ 세라믹의 유전손실에 미치는 Mn 첨가의 영향)

  • 김태중;한주환;이재열;이희영
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2000.07a
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    • pp.436-439
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    • 2000
  • Change of dielectric loss of use in high relative permitivity capacitor BaTiO$_3$ ceramic depends on Mn doping have been investigated. The powders used in this study were commercial BaTiO$_3$, TiO$_2$and, MnCO$_3$. Sample was fabricated by conventional ceramic process. The quantity of Mn was changed gradually from 0.lmol% to 10mo1%. The sintering densities were reduced with increasing amount of MnCO$_3$. This result is because of increase of low density second phase BaMnO$_3$. When the samples were doped by over 0.2mol% of MnCO$_3$, average grain sizes were enlarge to several tens ${\mu}{\textrm}{m}$. The dielectric losses were reduced by Mn doping to lmol% but, increased from lmol% to 10mo1% gradually.

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