• Title/Summary/Keyword: Deposition Mechanism

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Fabrication of CVD SiC Double Layer Structure from the Microstructural Change Through Input Gas Ratio (입력기체비를 이용한 미세구조 변화로부터 화학증착 탄화규소의 복층구조 제작)

  • 오정환;왕채현;최두진;송휴섭
    • Journal of the Korean Ceramic Society
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    • v.36 no.9
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    • pp.937-945
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    • 1999
  • In an effort to protect a RBSC(reaction -bonded SiC) tube SiC films from methyltrichlorosilane(MTS) by low pressure chemical vapor deposition were deposited in hydrogen atmosphere on the RBSC(reaction-bonded SiC) substrates over a range of input gas ratio(${\alpha}=P_{H2}/P_{MTS}=Q_{H2}/Q_{MTS}$=1 to 10) and deposition temperatures(T=1050~1300$^{\circ}C$). At the temper-ature of 1250$^{\circ}C$ the growth rate of SiC films increased and then decreased with decreasing the input gas ratio. The microstructure of SiC films was changed from granular type structure exhibiting (111) preferred orientation in the high input gas ratios to faceted columnar grain structure showing (220) in the low input gas ratios. The similar microstructure change was obtained by increasing the deposition temperature. These results were closely related to a change of deposition mechanism. Double layer structure having granular type and faceted ciolumnar grain structure from the manipulation of mechanism. Double layer structure having granular type and faceted columnar grain structure from the manipulation of the input gas ratio without changing the deposition temperatue was successfully fabricated through in -site process.

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IBAD-MgO technology for coated conductors

  • Jo, William
    • Progress in Superconductivity and Cryogenics
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    • v.18 no.3
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    • pp.1-5
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    • 2016
  • Ion-beam assisted deposition (IBAD) technology has been successfully applied to high-temperature superconductor coated conductors (CC) as textured substrates. Since the coated conductors were proposed as a potential framework for utilizing the superior transport characteristics of $YBa_2Cu_3O_7$ and related cuprate oxides, several methods including rolling-assisted bi-axial textured substrates (RABiTS) and inclined substrate deposition (ISD), as well as IBAD, have been attempted. As of 2016, most companies that are trying to commercialize CC adapt IBAD technology except for American Superconductors who use RABiTS predominantly. For the materials in the IBAD process, initial efforts to use yttria-stabilized zirconia (YSZ) or related fluorites in Fujikura in Japan have quickly given way to MgO which technique was developed by Stanford University in the USA. In this review, we present a historical overview of IBAD technology, in particular, for the application of CC. We describe the key scientific understanding of nucleation, the texturing mechanism, and the growth of large bi-axial grains and discuss some potential new IBAD materials and systems for large-scale production.

New Mechanism of Thin Film Growth by Charged Clusters

  • Hwang, Nong-Moon;Kim, Doh-Yeon
    • Proceedings of the Korea Association of Crystal Growth Conference
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    • 1999.06a
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    • pp.115-127
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    • 1999
  • The charged clusters or particles, which contain hundreds to thousands of atoms or even more, are suggested to form in the gas phase in the thin film processes such as CVD, thermal evaporation, laser ablation, and flame deposition. All of these processes are also used in the gas phase synthesis of the nanoparticles. Ion-induced or photo-induced nucleation is the main mechanism for the formation of these nanoclusters or nanoparticles inthe gas phase. Charged clusters can make a dense film because of its self-organizing characteristics while neutral ones make a porous skeletal structure because of its Brownian coagulation. The charged cluster model can successfully explain the unusual phenomenon of simultaneous deposition and etching taking place in diamond and silicon CVD processes. It also provides a new interpretation on the selective deposition on a conducting material in the CVDd process. The epitaxial sticking of the charged clusters on the growing surface is gettign difficult as the cluster size increases, resulting in the nanostructure such as cauliflowr or granular structures.

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New mechanism of thin film growth by charged clusters

  • Hwang, Nong-Moon;Kim, Doh-Yeon
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.9 no.3
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    • pp.289-294
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    • 1999
  • The charged clusters or particles, which contain hundreds to thousands of atoms or even more, are suggested to from in the gas phase in the thin film processes such as CVD, thermal evaporation, laser ablation, and flame deposition. All of these processes are also phase synthesis of the nanoparticels. Ion-induced or photo-induced nucleation is the main mechanism for the formation of these nanoclusters or nanoparticles in the gas phase. Charge clusters can make a dense film because of its self-organizing characteristics while neutral ones make a porous skeletal structure because of its Brownian coagulation. The charged cluster model can successfully explain the unusual phenomenon of simultaneous deposition and etching taking place in diamond and silicon CVD processes. It also provides a new interpretation on the selective deposition on a conducting material in the CVD process. The epitaxial sticking of the charged clusters on the growing surface is getting difficult as the cluster size increases, resulting in the nanostructure such as cauliflower or granular structures.

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Simulation Study on the Etching Mechanism of the Bosch Process (보쉬 공정의 식각 메커니즘에 대한 전산모사 연구)

  • Kim, Chang-Gyu;Moon, Jae-Seung;Lee, Won-Jong
    • Korean Journal of Metals and Materials
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    • v.49 no.10
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    • pp.797-804
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    • 2011
  • In this study, the mechanisms of the three steps (the polymer deposition step, the polymer etching step and the Si etching step) that constitute the Bosch process were investigated. The effects of radicals and ions on each step were quantitatively analyzed by comparing the simulated aspect ratio dependency of the deposition or etch rate with the experimental results. In the polymer deposition step, fluorocarbon polymer is deposited by chemical reactions of $CF_x$ radicals, of which the reaction probability is 0.13. Although the polymer etching step and the Si etching step were conducted under the same conditions, the etching mechanisms of polymer and Si were found to be quite different. In the polymer etching step, both chemical etching and physical sputter-etching contribute to the polymer etching. Whereas, in the Si etching step, Si is chemically etched by F radicals, of which the reactivity is greatly increased by the bombardment of energetic ions.

Study on the Mechanism and Modeling for Super-filling of High-Aspect-Ratio Features with Copper by Catalyst Enhanced Chemical Vapor Deposition Coupled with Plasma Treatment (플라즈마 처리와 결합된 Cu 촉매반응 화학기상증착법의 메커니즘과 고종횡비 패턴의 충진양상 전산모사에 대한 연구)

  • Kim, Chang-Gyu;Lee, Do-Seon;Lee, Won-Jong
    • Korean Journal of Metals and Materials
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    • v.49 no.4
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    • pp.334-341
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    • 2011
  • The mechanism behind super-filling of high-aspect-ratio features with Cu by catalyst-enhanced chemical vapor deposition (CECVD) coupled with plasma treatment is described and the metrology required to predict the filling feasibility is identified and quantified. The reaction probability of a Cu precursor was determined as a function of substrate temperature. Iodine adatoms are deactivated by the bombardment of energetic particles and also by the overdeposition of sputtered Cu atoms during the plasma treatment. The degree of deactivation of adsorbed iodine was experimentally quantified. The quantified factors, reaction probability and degree of deactivation of iodine were introduced to the simulation for the prediction of the trench filling aspect by CECVD coupled with plasma treatment. Simulated results show excellent agreement with the experimental filling aspects.

Electrokinetic deposition of individual carbon nanotube onto an electrode gap

  • Han Chang-Soo;Seo Hee-Won;Lee Hyung-Woo;Kim Soo-Hyun;Kwak Yoon-Keun
    • International Journal of Precision Engineering and Manufacturing
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    • v.7 no.1
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    • pp.42-46
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    • 2006
  • This paper presents a method for deposition an individual carbon nanotube (CNT). The alignment of a single CNT is very useful to perform studies related to applications in FET (Field Emitted Transistor), SET (Single Electron Transistor) and to make chemical sensor as well as bio sensors. In this study, we developed the deposition method of a CNT individualized in a solution. Using the electrokinetic method, we found the optimum conditions to assemble the nanotube and discussed about plausible explanation for the assembling mechanism. These results will be available to use for making the CNT sensor device.

Characteristics of Laser Aided Direct Metal Deposition Process for Tool Steel (공구강을 이용한 레이저 직접 금속조형 공정의 적층 특성)

  • 장윤상
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2004.10a
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    • pp.327-330
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    • 2004
  • Laser aided direct metal deposition (LADMD) process offers the ability to make a metal component directly from 3-D CAD dimensions. A 3-D object can be formed by repeating laser cladding layer by layer. The key of the build-up mechanism is the effective control of powder delivery and laser power to be irradiated into the melt-pool. A feedback control system using optical sensors is introduced to control laser power and powder mass flow rate. Using H13 tool steel and $CO_2$ laser system, comprehensive analysis are executed to test the efficiency of the system. In addition, the dimensional characteristics of directed deposited material are investigated with the parameters of deposition thickness, laser power, traverse speed and powder mass flow rate.

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The electrical conduction characteristics of polymide thin films fabricated by vapor deposition polymerization(VDP) method based on PMDA and 4,4'-DDE monomer (진공증착중합법을 이용하여 PMDA와 4,4'-DDE 단량체로 제조한 polyimide박막의 전기전도 특성)

  • 김형권;이덕출
    • Electrical & Electronic Materials
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    • v.9 no.8
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    • pp.776-782
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    • 1996
  • The electrical properties of vapor deposition polymerized polymide thin films for getting an in-line system with manufacturing process of semiconductor device, have been studied. Polyimide thin films fabricated by vapor deposition polymerization(VDP) method based on PMDA and 4,4'-DDE monomer were confirmed by FT-IR spectra. It is found that the major conduction carriers of thin films are ions, and the hopping length of ions is almost same with monomer length at the temperature over 120.deg. C through the analysis of electrical conduction mechanism. Also, The activation energy is about 0.69 eV at the temperature of >$30^{\circ}C$ - >$150^{\circ}C$ and it is shown that the resistivity at which thin films can be used as an insulating film between layers of semiconductor device, is 3.2*10$^{15}$ .ohm.cm.

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Onset on the Rate Limiting Factors of InP Film Deposition in Horizontal MOCVD Reactor (수평형 MOCVD 반응기 내의 InP 필름성장 제어인자에 대한 영향 평가)

  • Im, Ik-Tae;Sugiyama, Masakazu;Nakano, Yoshiyaki;Shimogaki, Yukihiro
    • Proceedings of the KSME Conference
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    • 2003.11a
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    • pp.73-78
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    • 2003
  • The InP thin films grown by metalorganic chemical vapor deposition (MOCVD) are widely used to optoelectronic devices such as laser diodes, wave-guides and optical modulators. Effects of various parameters controlling film growth rate such as gas-phase reaction rate constant, surface reaction rate constant and mass diffusivity are numerically investigated. Results show that at the upstream region where film growth rate increases with the flow direction, diffusion including thermal diffusion plays an important role. At the downstream region where the growth rate decreases with flow direction, film deposition mechanism is revealed as a mass-transport limited. Mass transport characteristics are also studied using systematic analyses.

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