• Progress in Superconductivity and Cryogenics
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• v.6 no.3
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• pp.6-11
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• 2004

YBa$_2$Cu$_3$$O_{7-x}$ (YBCO) films were deposited on MgO(100) and SrTiO$_3$(100) single crystal substrates by cold-wall type MOCVD method using continuous source supplying system. Under the deposition temperature of 740∼76$0^{\circ}C$, c-axis oriented YBCO films were obtained. In case of the YBCO films deposited on MgO (100) single crystal substrate, the critical temperature (T$_{c}$) was under 81 K regardless of the deposition conditions, whereas T$_{c}$ of the YBCO films deposited on SrTiO$_3$(100) single crystal substrate was 83∼84 K. The critical current (I$_{c}$) of the YBCO film deposited on SrTiO$_3$(100) single crystal substrate for 30 min was 49 A/cm-width and the critical current density (J$_{c}$) was 0.82 MA/$\textrm{cm}^2$ to film thickness of 0.6 ${\mu}{\textrm}{m}$. I$_{c}$ increased to 84.4 A/cm-width as the deposition time increased to 50 min, but J$_{c}$ decreased to 0.53 MA/$\textrm{cm}^2$ to film thickness of 1.8 ${\mu}{\textrm}{m}$.rm}{m}$.

• Bulletin of the Korean Chemical Society
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• v.30 no.4
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• pp.853-856
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• 2009

Highly polycrystalline copper indium diselenide (CuInSe2, CIS) thin films were deposited on glass or ITO glass substrates by two-stage metal organic chemical vapor deposition (MOCVD) at relatively mild conditions, using Cuand In/Se-containing precursors. First, pure Cu thin film was prepared on glass or ITO glass substrates by using a single-source precursor, bis(ethylbutyrylacetate)copper(II) or bis(ethylisobutyrylacetato)copper(II). Second, on the resulting Cu films, tris(N,N-ethylbutyldiselenocarbamato)indium(III) was treated to produce CuInSe2 films by MOCVD method at 400 ${^{\circ}C}$. These precursors are very stable in ambient conditions. In our process, it was quite easy to obtain high quality CIS thin films with less impurities and uniform thickness. Also, it was found that it is easy to control the stoichiometric ratio of relevant elements on demands, leading to Cu or In rich CIS thin films. These CIS films were analyzed by XRD, SEM, EDX, and Near-IR spectroscopy. The optical band gap of the stoichiometric CIS films was about 1.06 eV, which is within an optimal range for harvesting solar radiation energy.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.11a
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• pp.23-23
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• 2009

Recently, the nanowire configuration of GST showed nanosecond-level phase switch at very low power dissipation, suggesting that the nanowires could be ideal for data storage devices. In spite of many advantages of IST materials, their feasibility in both thin films and nanowires for electronic memories has not been extensively investigated. The synthesis of the chalcogenide nanowires was mainly preformed via a vapor transport process such as vapor-liquid-solid (VLS) growth at a high temperature. However, in this study, IST nanowires as well as thin films were prepared at a low temperature (${\sim}250^{\circ}C$) by metal organic chemical vapor deposition(MOCVD) method, which is possible for large area deposition. The IST films and/or nanowires were selectively grown by a control of working pressure at a constant growth temperature by MOCVD. In-Sb-Te NWs will be good candidate materials for high density PRAM applications. And MOCVD system is powerful for applying ultra scale integration cell.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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• 2002.02a
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• pp.119-122
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• 2002

The NiO buffer layers for YBCO coated conductor were prepared on textured Ni substrates by MOCVD method and the degree of texturizing and the surface roughness were analyzed X-ray pole figure and AFM and SEM. Processing variables were oxygen partial pressure and substrate temperature. (200) textured NiO layer was formed at 450~$470^{\circ}C$ and oxygen partial pressure of 1.67 Torr. Out-of-plane($\omega$-scan) and in-plane($\Phi$-scan) texture were $10.34^{\circ}$ and $10.00^{\circ}$ respectively. The surface roughness estimated by atomic force microscopy was in the range of 3.1~4.6 nm.

• Bulletin of the Korean Chemical Society
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• v.30 no.1
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• pp.114-118
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• 2009

A new Zn/O single source precursor, TMEDA-Zn$(eacac)_2$, has been synthesized by using N, N, N’, N’-tetramethylethylendiamine (TMEDA), sodium ethyl-acetoacetate, and $ZnCl_2$. From this organometallic precursor, ZnO thin films have been successfully grown on Si (100) substrates through the metal organic chemical vapor deposition (MOCVD) method at relatively mild conditions in the temperature range of 390~430 ${^{\circ}C}$. The synthesized ZnO films have been found to possess average grain sizes of about 70 nm with an orientation along the c-axis. The precursor and ZnO films are characterized through infrared spectroscopy, nuclear magnetic resonance spectroscopy, EI-FAB-spectroscopy, elemental analyses, thermal analysis, X-ray diffraction, and field emission scanning electron microscopic analyses.

• 한국초전도학회:학술대회논문집
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• v.10
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• pp.56-60
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• 2000

Cube texture를 갖는 Ni기판위에 MOCVD(Metal Chemical Vapor Deposition)를 이용하여 NiO, CeO$_2$, YBCO 박막을 제조하였다. NiO(200)와 CeO$_2$(200) buffer layer는 450${\sim}$470$^{\circ}$C에서 10분간 MOCVD방법으로 (100)<001>Ni 기판위에 직접 증착하였다. 제조된 NiO, CeO$_2$ buffer layer는 조직이 치밀하며 표면의 상태가 매우 좋으며 Ni기판 위에 epitaxial하게 성장하였다. NiO는 Ni기판과 NiO<100>//Ni<100>의 방위관계를 가지고 성장하였으며, CeO$_2$는 증착조건에 따라 CeO$_2$ <100>//Ni<100> 및 CeO$_2$ <110>//Ni<100> 의 방위관계를 가지고 성장하였다. 증착된 NiO막과 CeO$_2$막에서 균열은 발생하지 않았다. MOCVD법으로 표면에 biaxial texture를 갖는 ceramic buffer를 증착시킨 NiO/Ni및 CeO$_2$/Ni 기판위에 YBCO박막을 MOCVD법으로 제조하였다. YBCO막은 기판온도 800$^{\circ}$C,증착압력 10torr, 산소분압을 0.7torr로 하여 10분간 행하였다. 공급원료의 조성에 따라 YBCO의 막의 texture와 형성되는 상이 변화되었다. NiO/Ni및 CeO$_2$/Ni 기판 위에 증착된 YBCO막은 c축 배향성을 가지고 성장하였으며, -scan 및 ${\varphi}$ -scan으로 측정한 (500)면의 in-plane과 (110)면의 out-of-plane의 FWHM(Full Width Half Maximum)값은 각각 10$^{\circ}$ 미만으로 우수하였다.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.377-377
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• 2012

Microprocessor technology now relies on copper for most of its electrical interconnections. Because of the high diffusivity of copper, Atomic layer deposition (ALD) $TaN_x$ is used as a diffusion barrier to prevent copper diffusion into the Si or $SiO_2$. Another problem with copper is that it has weak adhesion to most materials. Strong adhesion to copper is an essential characteristic for the new barrier layer because copper films prepared by electroplating peel off easily in the damascene process. Thus adhesion-enhancing layer of cobalt is placed between the $TaN_x$ and the copper. Because, cobalt has strong adhesion to the copper layer and possible seedless electro-plating of copper. Until now, metal film has generally been deposited by physical vapor deposition. However, one draw-back of this method is poor step coverage in applications of ultralarge-scale integration metallization technology. Metal organic chemical vapor deposition (MOCVD) is a good approach to address this problem. In addition, the MOCVD method has several advantages, such as conformal coverage, uniform deposition over large substrate areas and less substrate damage. For this reasons, cobalt films have been studied using MOCVD and various metal-organic precursors. In this study, we used $C_{12}H_{10}O_6(Co)_2$ (dicobalt hexacarbonyl tert-butylacetylene, CCTBA) as a cobalt precursor because of its high vapor pressure and volatility, a liquid state and its excellent thermal stability under normal conditions. Furthermore, the cobalt film was also deposited at various $H_2/NH_3$ gas ratio(1, 1:1,2,6,8) producing pure cobalt thin films with excellent conformality. Compared to MOCVD cobalt using $H_2$ gas as a reactant, the cobalt thin film deposited by MOCVD using $H_2$ with $NH_3$ showed a low roughness, a low resistivity, and a low carbon impurity. It was found that Co/$TaN_x$ film can achieve a low resistivity of $90{\mu}{\Omega}-cm$, a low root-mean-square roughness of 0.97 nm at a growth temperature of $150^{\circ}C$ and a low carbon impurity of 4~6% carbon concentration.

• Journal of the Korean Vacuum Society
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• v.9 no.4
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• pp.373-378
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• 2000

There was a great difference in the formation kinetics of $TiO_2$ and $Bi_2O_3$ on silicon, but the growth of bismuth titanate (BIT) thin film was mainly limited by the formation of $TiO_2$. As a result, the BIT film was easy to be lack of bismuth. The pulse injection metalorganic chemical vapor deposition (MOCVD) process was introduced in order to overcome this problem by recovering the insufficient bismuth content in the film. By this pulse injection method, bismuth content was increased and also the uniform in-depth composition of the film was attained with a abrupt $Bi_4Ti_3O_{12}/Si$ interface. In addition, the crystallinity of $Bi_4Ti_3O_{12}$ thin film prepared by pulse injection process was greatly improved and the leakage current density was lowered by 1/2~1/3 of magnitude. Clockwise hysteresis of C-V was observed and the ferroelectric switching was confirmed for $Bi_4Ti_3O_{12}$ film deposited by pulse injection method.

• Progress in Superconductivity
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• v.8 no.1
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• pp.27-32
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• 2006

[$YBa_2Cu_3O_{7-x}$] thin films were deposited on various buffered-templates by a metal organic chemical vapor deposition(MOCVD). Three different templates of $CeO_2/YSZ/CeO_2/pure-Ni(CYC),\;CeO_2/YSZ/Y_2O_3/Ni-3at.%W(YYC)$ and $CeO_2/IBAD-YSZ$/stainless steel were used. The Ni and Ni-W alloy tapes were biaxially textured by cold rolling and annealing heat treatment. The dense YBCO films were grown on both the IBAD and YYC templates with no microcrack, while the YBCO films on the CYC templates were grown with the formation of microcracks and NiO. The YBCO film on the YYC template showed the higher $I_c$ than that on CYC template. Especially, the IBAD templates with a thin $CeO_2$(type I) and thick $CeO_2$(type II) top layer were used to compare the deposition nature of the YBCO on them. Comparing the current property of the YBCO films on IBAD templates, the YBCO film deposited on thick $CeO_2$ layer was better than the film on thin $CeO_2$ layer.

• Progress in Superconductivity and Cryogenics
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• v.4 no.2
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• pp.5-10
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• 2002

Deposition condition of NiO that is one of Possible buffer layers for YBCO coated conductors was studied. NiO was deposited on textured Ni substrates by a MOCVD (metal-organic chemical vapor deposition) method. The degree of texture, and the surface roughness were analyzed by X-ray Pole figure, atomic force microscope and scanning electron microscope. The (111) and (200) textures were competitively developed , depending on an oxygen partial Pressure(PO2) and deposition temperature (Tp). The (200) textured NiO layer was deposited at Tp=450~47$0^{\circ}C$ and PO2= 1.67 Torr Out-of-Plane ($\omega$-scan) and in-plane ($\Phi$-scan) textures of the (200) NiO films were as good as 10.34$^{\circ}$ and 10.00$^{\circ}$ respectively The AFM surface roughness of NiO was in the range of 3~4.5 nm at PO2=0.91~3.34 Torr and at Tp=47$0^{\circ}C$ , and in the range of 3~13 nm at TP=450~53$0^{\circ}C$ and at PO2=1.67 Torr.