• Title/Summary/Keyword: thermal co-evaporation

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The development of the highly efficient Circular Nozzle Source by using a study on the flux distributions of nozzle type thermal evaporation sources

  • Kim, Sung-Moon;Jeong, Kwang-Ho
    • 한국정보디스플레이학회:학술대회논문집
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    • 2008.10a
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    • pp.1171-1174
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    • 2008
  • We studied the properties of vapor flux distributions of nozzle shaped thermal evaporation sources and the factors, which can change the flux distributions such as nozzle structure. We used a simulation and experiment methods for this study. By using the results of our study, we improved the Circular Nozzle Source, which can make uniform thin films without substrate rotation, into more efficient source.

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Microstructure and CO Gas Sensing Properties of Ag-CuO-SnO2 Thin Films Prepared by Co-Evaporation and Thermal Oxidation (공증발과 열산화로 제조한 Ag-CuO-SnO2 박막에서 미세조직과 CO 가스 감지특성)

  • Ji, In-Geol;Han, Kyu-Suk;Oh, Jae-Hee;Ko, Tae-Gyung
    • Journal of the Korean Ceramic Society
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    • v.46 no.4
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    • pp.429-435
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    • 2009
  • In this study, we investigated microstructure and the CO gas sensing properties of Ag-CuO-$SnO_2$ thin films prepared by co-evaporation and subsequently thermal oxidation at air atmosphere. The sensitivity of a Cu-Sn films, thermally oxidized at $600^{\circ}C$, is strongly affected by the amount of Cu. At Cu:7 wt%-Sn:93 wt%, the film exhibited a maximum sensitivity of ${\sim}2.3$ to CO gas of 1000 ppm at $300^{\circ}C$. In contrast, the sensitivity of a Sn-Ag film did not change significantly with the amount of Ag. An enhanced sensitivity of ${\sim}3.7$ was observed in the film with a composition of Ag:3 wt%-Cu:4 wt%-Sn:93 wt%, when thermally oxidized at $600^{\circ}C$. In addition, this thin film shows a response time of ${\sim}80$ sec and a recovery time of ${\sim}450$ sec to 1000 ppm CO gas. The results demonstrate that the CO sensitivity of the Ag-CuO-$SnO_2$ thin films may be closely associated with coexistence of $SnO_2$ and SnO phase, decrease in average particle size, and a porous microstructure. We also suggest that co-evaporation and followed by thermal oxidation is a very simple and effective method to prepare oxide gas sensor thin films.

Structural characteristics of ZnO nanostructures synthesized by the thermal evaporation method (열증착법으로 합성된 ZnO 나노 구조체의 구조적 특성)

  • Bang, Sin-Young;Kim, Woo-Sik;Chung, Jun-Ho;Choi, Bong-Geun;Shim, Kwang-Bo
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.18 no.2
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    • pp.81-86
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    • 2008
  • ZnO nanowires were synthesized by the thermal evaporation method and their growth mechanisms were confirmed by the characterization of the structural features depending on the growth conditions. The increase of vaporization temperature accelerates the growth rate and morphologies of ZnO nanowires were drastically changed at the temperature over 1000$^{\circ}C$, because of changed $CO/CO_2$ partial pressure. Au particles play their role on growth of ZnO nanowire as catalyst at growth temperature over 700$^{\circ}C$. The synthesized ZnO nanowires exhibit blue emission at 380 nm.

Study on CeO2 Single Buffer on RABiTS for SmBCO coated Conductor (SmBCO 초전도 층착을 위한 RABiTS상의 CeO2 단일 버퍼 연구)

  • Kim, Tae-Hyung;Kim, Ho-Sup;Lee, Nam-Jin;Ha, Hong-Soo;Ko, Rock-Kil;Ha, Dong-Woo;Song, Kyu-Jeong;Oh, Sang-Soo;Park, Kyung-Chae
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.20 no.6
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    • pp.546-549
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    • 2007
  • As a rule, high temperature superconducting coated conductors have multi-layered buffers consisting of seed, diffusion barrier and cap layers. Multi-buffer layer deposition requires longer fabrication time. This is one of main reasons which increases fabrication cost. Thus, single buffer layer deposition seems to be important for practical coated conductor process. In this study, a single layered buffer deposition of $CeO_2$ for low cost coated conductors has been tried using thermal evaporation technique. 100 nm-thick $CeO_2$ layers deposited by thermal evaporation were found to act as a diffusion layer. $1\;{\mu}m-thick$ SmBCO superconducting layers were deposited by thermal co-evaporation on the $CeO_2$ buffered Ni-5%W substrate. Critical current of 90 A/cm was obtained for the SmBCO coated conductors.

YBCO - film production by thermal co-evaporation for microwave and electrical power applications

  • Prusseit, W.;Semerad, R.
    • 한국초전도학회:학술대회논문집
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    • v.10
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    • pp.145-145
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    • 2000
  • Large area YBCO - films are series produced by thermal co-evaporation using a deposition scheme known as Garching process, which allows intermittent oxygen supply in a high vacuum ambient by an oxygen cup spaced closely underneath the moving substrates. The deposition area of 9" diameter is capable to handle very large wafers up to 8" diam. or numerous smaller wafers. The large distance between substrates and boat sources and an elaborate heater design guarantee excellent film uniformity over the entire deposition area. YBCO - films deposited by this technique are commercially fabricated for a variety of applications - the most prominent are resistive fault current limiters and microwave filters for mobile or satellite communications. IMUX and OMUX - filters are currently space qualined by Robert Bosch GmbH and are expected to be launched and installed on an experimental platform of the international space station ALPHA in 2001. Both of the above applications require quite different film specifications on the one hand, but at the same time extremely high uniformity and reproducibility on the other hand, since hundreds of YBCO - films are combined to large systems or have to be approved for manned space missions. The success of such projects is direct evidence that the technique of thermal evaporation is readily capable to meet these high demands and has become the major deposition technique to support the emerging HTS market.

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Magnetoresistance Behavior of CuCo and AgCo Films using a Thermal Evaporation (열증착법으로 제조한 박막헝 CuCo와 AgCo의 자기저항 효과)

  • Song, Oh-Sung;Yoon, Ki-Jeong
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.7 no.5
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    • pp.811-816
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    • 2006
  • The single layered magnetic thin films with anisotropic magnetoresistance behavior have advantage on micro integration due to their low cost in manufacturing. Although the conventional MCo (M=Cu, Ag) amorphous ribbons using a rapid solidification process have showed appropriate for magnetic property for bulk devices, they are not appropriate for micro-scale devices due to their brittleness. We prepared the thermal evaporated 100 nm-thick $Cu_{1-x}Co_x\;and\;Ag_{1-x}Co_x(x=0.1{\sim}0.7)$ films on silicon wafers and investigated the magnetic property of the as-depo films such as magnetization and magnetoresistance ratio. We confirmed that the maximum MR ratio of 1.4 and 2.6% at the external field of 0.5 Tesla in $CuCo_{30},\;AgCo_{40}$ films, respectively. Our result implies that AMR may be slightly less than those of the conventional CuCo and AgCo ribbons due to surface scattering, but their AMR ratio be enough for micro-scale application with easy integration compatibility for the process without surface oxidation.

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$CeO_2$ Single Buffer Deposition on RABiTS for SmBCO Coated Conductor

  • Kim, T.H.;Kim, H.S.;Ha, H.S.;Yang, J.S.;Lee, N.J.;Ha, D.W.;Oh, S.S.;Song, K.J.;Jung, Y.H.;Pa, K.C.
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2006.11a
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    • pp.180-181
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    • 2006
  • As a rule, high temperature superconducting coated conductors have multi-layered buffers consisting of seed, diffusion barrier and cap layers. Multi-buffer layer deposition requires longer fabrication time. This is one of main reasons which increases fabrication cost Thus, single buffer layer deposition seems to be important for practical coated conductor process. In this study, a single layered buffer deposition of $CeO_2$ for low cost coated conductors has been tried using thermal evaporation technique 100nm-thick $CeO_2$ layers deposited by thermal evaporation were found to act as a diffusion layer. $0.4{\mu}m$-thick SmBCO superconducting layers were deposited by thermal co-evaporation on the $CeO_2$ buffered Ni-W substrate. Critical current of 118A/$cm^2$ was obtained for the SmBCO coated conductors.

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A Study on IIM Process for Ultra-Shallow Cobalt Silicide Junctions (극히 얇은 코발트 실리사이드 접합을 위한 IIM 공정에 관한 연구)

  • 이석운;민경익;주승기
    • Journal of the Korean Institute of Telematics and Electronics A
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    • v.29A no.8
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    • pp.89-98
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    • 1992
  • IIM(Implantation Into Metal) process usning Co silicides has been investigated to obtain ultra-shallow junctions less than 0.1$\mu$m. Rapid Thermal Annealing using halogen lamps was employed to form CoSi$_2$ and junctions simultaneously.. Resistivities of CoSi$_2$ were 13-17$\mu$ $\Omega$-cm. CoSi$_2$/p$^{+}$/Si and CoSi$_2$/n$^{+}$/Si junction were formed by diffusion of B and As, respectively, from Co film. It was found out that B and As were severely lost by the evaporation during high temperature annealing Therefore SiO$_2$ capping layers were introduced to prevent the evaporation of the implanted dopants from the films. Investigation of the behavior of dopants with respect to annealing time revealed that increasing the annealing time enhanced the diffusion of dopants into Si from CoSi$_2$.

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System of stable action waveform by pulse special quality of obstetrics and gynecology pulse style $CO_2$ laser (산부인과 펄스형 $CO_2$ 레이저의 펄스 특성에 의한 안정된 동작파형의 시스템)

  • Kim, Whi-Young
    • Proceedings of the KIEE Conference
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    • 2007.04a
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    • pp.55-57
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    • 2007
  • $CO_2$ laser sees that is most suitable to get this effect through minimum formation damage and advantage that is root enemy of effect that happen in minimum cellular tissue depth of 0.1mm is stable living body organization or internal organs institution. Formation damage by ten can be related in formation's kind or energy density, length of evaporation time. If shorten evaporation time, surroundings cellular thermal damage 200 - because happen within 400ums laser beam in rain focus sacred ground surroundings cellular, tissue without vitiation me by evaporation Poe of very small floor as is clean steam can. Application is possible to vulva cuticle cousins by a paternal aunt quantity, uterine cancer, cuticle tumor by laser system that $CO_2$ laser gets into standard in obstetrics and gynecology application. Because effect that super pulse output is ten enemies of laser if uniformity one pulse durations are short almost is decreased, most of all pulse module special quality of pulse style $CO_2$ laser for obstetrics and gynecology mode stabilization by weight very, in this research to get into short pulse duration and higher frequency density, do switching by high frequency in DC-DC Converter output DC's ripple high frequency to be changed, high frequency done current ripple amount of condenser for output filter greatly reduce can. Ripple of output approximately to Zero realization applying possible inductor realization through a special quality experiment do.

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