• Title, Summary, Keyword: Metal oxide chemical vapor deposition

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Preparation of Yttria Stabilized zirconia Films by the Electrochemical Vapor Deposition (전기화학증착에 의한 이트리아 안정화 지르코니아 박막의 제조)

  • 정지원;박동원;전치훈;최병진;김대룡
    • Journal of the Korean Ceramic Society
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    • v.31 no.5
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    • pp.477-484
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    • 1994
  • The yttria stabilized zirconia(YSZ) thin films for solid oxide fuel cell (SOFC) were fabricated by an electrochemical vapor deposition(EVD) technique using YCl3+ZrCl4+H2O gas system. The YSZ films were deposited under reduced pressure at the temperature of 1000~120$0^{\circ}C$ on the porous alumina substrates. The deposition rate, chemical composition and growth morphology were investigated by SEM, XRD, EDS. The growth rates of the films obeyed a parabolic rate law, representing that the growing process is controlled by an electrochemical transport through the YSZ film. The Y2O3 content of the films was about 10 mol%, equal to the composition of metal chloride reactant gases, approximately. The YSZ films were highly dense, the growing features showed columnar structure and surface morphologies were changed with the EVD conditions.

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Study the Effects of Precursor Concentration on ZnO Nanorod Arrays by Hydrothermal Method (수열합성 법으로 성장된 산화 아연 나노로드의 전구체 농도에 따른 구조적, 광학적 특성 연구)

  • Ryu, H.
    • Journal of the Korean Vacuum Society
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    • v.18 no.1
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    • pp.73-78
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    • 2009
  • Zinc Oxide (ZnO) nanorods arrays were deposited on ZnO buffered p-Si(100) substrates by hydrothermal method. The ZnO buffer layer with a thickness of 30 nm was deposited by metal oxide chemical vapor deposition at $500^{\circ}C$. The structural and optical properties of ZnO nanorods arrays controlled by precursor concentrations from 0.06 to 0.5 M were studied by FE-SEM(field emission scanning electron microscopy), XRD(X-ray diffraction), and PL(photoluminescence), respectively. It was found that the structural and optical properties of ZnO nanorods arrays are changed significantly with increase of precursor concentration. The sizes of diameter and length of nanorods were increased as the concentration increase, and good optical property was shown with the concentration of 0.3 M.

The Deposition of Hafnium Oxide Thin Film using MOCVD (MOCVD를 이용한 Hafnium Oxide 박막 증착)

  • 오재민;이태호;김영순;현광수;안진호
    • Proceedings of the International Microelectronics And Packaging Society Conference
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    • pp.198-202
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    • 2002
  • $HfO_2$films were grown on Si substrate in the temperature range $250~550^{\circ}C$ using metal organic chemical vapor deposition (MOCVD) technique for a gate dielectric. Hafnium tart-butoxide and Oxygen gas were used as precursors and N2 was used as carrier gas. Impurity distribution and film structure(including interfacial layer) were studied at the deposition temperature range between 25$0^{\circ}C$ and $550^{\circ}C$. The growth rate and impurty distribution decreased with increasing temperature. The electrical properties of $HfO_2$were investigated with C-V, 1-V method and showed it has a good properties as a gate dielectric.

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Atomic layer chemical vapor deposition of Zr $O_2$-based dielectric films: Nanostructure and nanochemistry

  • Dey, S.K.
    • Electrical & Electronic Materials
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    • v.16 no.9
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    • pp.64.2-65
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    • 2003
  • A 4 nm layer of ZrOx (targeted x-2) was deposited on an interfacial layer(IL) of native oxide (SiO, t∼1.2 nm) surface on 200 mm Si wafers by a manufacturable atomic layer chemical vapor deposition technique at 30$0^{\circ}C$. Some as-deposited layers were subjected to a post-deposition, rapid thermal annealing at $700^{\circ}C$ for 5 min in flowing oxygen at atmospheric pressure. The experimental x-ray diffraction, x-ray photoelectron spectroscopy, high-resolution transmission electron microscopy, and high-resolution parallel electron energy loss spectroscopy results showed that a multiphase and heterogeneous structure evolved, which we call the Zr-O/IL/Si stack. The as-deposited Zr-O layer was amorphous $ZrO_2$-rich Zr silicate containing about 15% by volume of embedded $ZrO_2$ nanocrystals, which transformed to a glass nanoceramic (with over 90% by volume of predominantly tetragonal-$ZrO_2$(t-$ZrO_2$) and monoclinic-$ZrO_2$(m-$ZrO_2$) nanocrystals) upon annealing. The formation of disordered amorphous regions within some of the nanocrystals, as well as crystalline regions with defects, probably gave rise to lattice strains and deformations. The interfacial layer (IL) was partitioned into an upper Si $o_2$-rich Zr silicate and the lower $SiO_{x}$. The latter was sub-toichiometric and the average oxidation state increased from Si0.86$^{+}$ in $SiO_{0.43}$ (as-deposited) to Si1.32$^{+}$ in $SiO_{0.66}$ (annealed). This high oxygen deficiency in $SiO_{x}$ indicative of the low mobility of oxidizing specie in the Zr-O layer. The stacks were characterized for their dielectric properties in the Pt/{Zr-O/IL}/Si metal oxide-semiconductor capacitor(MOSCAP) configuration. The measured equivalent oxide thickness (EOT) was not consistent with the calculated EOT using a bilayer model of $ZrO_2$ and $SiO_2$, and the capacitance in accumulation (and therefore, EOT and kZr-O) was frequency dispersive, trends well documented in literature. This behavior is qualitatively explained in terms of the multi-layer nanostructure and nanochemistry that evolves.ves.ves.

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Tungsten Coating on Metal Substrates by Using Tungsten Oxide Powder (텅스텐 산화 분말을 이용한 텅스덴 코팅에 관한 연구)

  • Lee, Seong;Kim, Eun-Pyo;Hong, Mun-Hui;Roh, Jun-Ung
    • Proceedings of the Korean Powder Metallurgy Institute Conference
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    • pp.53-53
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    • 2002
  • 본 연구에서는 산화텅스텐($WO_3$) 분말을 이용하여 여러 금속 기판에 텅스텐 박막을 코팅하는 방법에 관한 연구를 수행하였다. 본 연구에서 언급되는 W 코팅은 Lee 등이 보고한 W, Cu 산화물을 이용하여 W-Cu 복합분말을 제조하는 것으로부터 아이디어가 출발되었으며, 본 연구의 결과는 기존의 6불화 텅스텐 가스($WF_6$) 를 열 분해하여 증착시키는 화학증착법(CVD: chemical vapor deposition)과 순수 텅스텐 target을 sputtering하여 증착시키는 물리증착법(PVD: physical vapor deposition)과 달리, 산화텅스텐 분말, 금속 기판, 및 수소 가스만을 사용하기 때문에 경제적으로 큰 장점이 있는 새로운 코팅법의 하나로 연구되었다. 본 연구에서는 새로운 코팅법의 기구와 여러 금속에서 코팅되는 W의 코팅 현상 등에 대해 간단히 언급하고자 하였다.

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Chemical vapor deposition of $TaC_xN_y$ films using tert-butylimido tris-diethylamido tantalum(TBTDET) : Reaction mechanism and film characteristics

  • Kim, Suk-Hoon;Rhee, Shi-Woo
    • Proceedings of the Materials Research Society of Korea Conference
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    • pp.24.1-24.1
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    • 2009
  • Tantalum carbo-nitride($T_aC_xN_y$) films were deposited with chemical vapor deposition(CVD) using tert-butylimido tris-diethylamido tantalum (TBTDET, $^tBu-N=Ta-(NEt_2)_3$, $Et=C_2H_5$, $^tBu=C(CH_3)_3$) between $350^{\circ}C$ and $600^{\circ}C$ with argon as a carrier gas. Fourier transform infrared (FT-IR)spectroscopy was used to study the thermal decomposition behavior of TBTDET in the gas phase. When the temperature was increased, C-H and C-N bonding of TBTDET disappeared and the peaks of ethylene appeared above $450^{\circ}C$ in the gas phase. The growth rate and film density of $T_aC_xN_y$ film were in the range of 0.1nm/min to 1.30nm/min and of $8.92g/cm^3$ to $10.6g/cm^3$ depending on the deposition temperature. $T_aC_xN_y$ films deposited below $400^{\circ}C$ were amorphous and became polycrystal line above $500^{\circ}C$. It was confirmed that the $T_aC_xN_y$ film was a mixture of TaC, graphite, $Ta_3N_5$, TaN, and $Ta_2O_5$ phases and the oxide phase was formed from the post deposition oxygen uptake. With the increase of the deposition temperature, the TaN phase was increased over TaC and $Ta_3N_5$ and crystallinity, work function, conductivity and density of the film were increased. Also the oxygen uptake was decreased due to the increase of the film density. With the increase of the TaC phase in $T_aC_xN_y$ film, the work function was decreased to 4.25eV and with the increase of the TaN phase in $T_aC_xN_y$ film,it was increased to 4.48eV.

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Electrochemical Properties of a Si3N4 Dielectric Layer Deposited on Anodic Aluminum Oxide for Chemical Sensors

  • Jo, Ye-Won;Lee, Sung-Gap;Yeo, Jin-Ho;Lee, Dong-Jin
    • Transactions on Electrical and Electronic Materials
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    • v.17 no.3
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    • pp.159-162
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    • 2016
  • We studied an electrolyte-dielectric metal (EDM) device based on a Si3N4 layer-coated anodic aluminium oxide (AAO) template for chemical sensors. The AAO templates were fabricated using a two-step anodization procedure at 0℃ and 70 V in 0.3 M oxalic acid, after which the Si3N4 was deposited on them using plasma enhanced chemical vapor deposition (PECVD). The average pore size was approximately 106 nm and the depth of the AAO templates was 24.6 nm to 86.5 nm. The Si3N4 layer-coated AAO is more stable than a single AAO template.

BST Thin Film Multi-Layer Capacitors

  • Choi, Woo Sung;Kang, Min-Gyu;Ju, Byeong-Kwon;Yoon, Seok-Jin;Kang, Chong-Yun
    • Proceedings of the Korean Vacuum Society Conference
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    • pp.319-319
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    • 2013
  • Even though the fabrication methods of metal oxide based thin film capacitor have been well established such as RF sputtering, Sol-gel, metal organic chemical vapor deposition (MOCVD), ion beam assisted deposition (IBAD) and pulsed laser deposition (PLD), an applicable capacitor of printed circuit board (PCB) has not realized yet by these methods. Barium Strontium Titanate (BST) and other high-k ceramic oxides are important materials used in integrated passive devices, multi-chip modules (MCM), high-density interconnect, and chip-scale packaging. Thin film multi-layer technology is strongly demanded for having high capacitance (120 nF/$mm^2$). In this study, we suggest novel multi-layer thin film capacitor design and fabrication technology utilized by plasma assisted deposition and photolithography processes. Ba0.6Sr0.4TiO3 (BST) was used for the dielectric material since it has high dielectric constant and low dielectric loss. 5-layered BST and Pt thin films with multi-layer sandwich structures were formed on Pt/Ti/$SiO_2$/Si substrate by RF-magnetron sputtering and DC-sputtering. Pt electrodes and BST layers were patterned to reveal internal electrodes by photolithography. SiO2 passivation layer was deposited by plasma-enhanced chemical vapor deposition (PE-CVD). The passivation layer plays an important role to prevent short connection between the electrodes. It was patterned to create holes for the connection between internal electrodes and external electrodes by reactive-ion etching (RIE). External contact pads were formed by Pt electrodes. The microstructure and dielectric characteristics of the capacitors were investigated by scanning electron microscopy (SEM) and impedance analyzer, respectively. In conclusion, the 0402 sized thin film multi-layer capacitors have been demonstrated, which have capacitance of 10 nF. They are expected to be used for decoupling purpose and have been fabricated with high yield.

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Synthesis and Characterization of CNTs/Metal/Al2O3 Nanocomposite Powders by Thermal CVD (열 CVD법에 의한 CNTs/Metal/Al2O3 나노복합분말의 합성 및 특성)

  • Choa Yong-Ho;Yoo Seung-Hwa;Yang Jae-Kyo;Oh Sung-Tag;Kang Sung-Goon
    • Journal of Korean Powder Metallurgy Institute
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    • v.12 no.2
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    • pp.146-150
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    • 2005
  • An optimum route to synthesize $Al_2O_3$-based composite powders with homogeneous dispersion of carbon nanotubes (CNTs) was investigated. CNTs/Metal/$Al_2O_3$ nanocomposite powders were fabricated by thermal chemical vapor deposition of $C_2H_2$ gas over metal/$Al_2O_3$ nanocomposite catalyst prepared by selective reduction of metal oxide/$Al_2O_3$ powders. The FT-Raman spectroscopy analysis revealed that the CNTs have single- and multi-walled structure. The CNTs with the diameter of 25-43 nm were homogeneously distributed in the metal/$Al_2O_3$ powders, and their characteristics were strongly affected by a kind of metal catalyst and catalyst size. The experimental results show that the composite powder with required size and dispersion of CNTs can be realized by control of synthesis condition.

Improved Contact Characteristics in a Single Tin-Oxide Nanowire Device by a Selective Reactive Ion Etching (RIE) Process (선택 건식에칭에 의한 단일 산화주석 나노와이어 소자의 접촉 특성 개선)

  • Lee, Jun-Min;Kim, Dae-Il;Ha, Jeong-Sook;Kim, Gyu-Tae
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.59 no.1
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    • pp.130-133
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    • 2010
  • Although many structures based on $SnO_2$ nanowires have been demonstrated, there is a limitation towards practical application due to the unwanted contact potential between the metal electrode and the $SnO_2$ nanowire. This is mostly due to the presence of the native oxide layer that acts as an insulator between the metal contact and the nanowire. In this study the contact properties between Ti/Au contacts and a single $SnO_2$ nanowire was compared to the electrical properties of a contact without the oxide layer. RIE(Reactive Ion Etching) is used to selectively remove the oxide layer from the contact area. The $SnO_2$ nanowires were synthesized by chemical vapor deposition (CVD) and dispersed on a $Si/Si_3N_4$ substrate. The Ti/Au (20nm/100nm) electrodes were formed bye-beam lithography, e-beam evaporation and a lift-off process.