• Title/Summary/Keyword: Plasma Gases

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Application of cold atmospheric microwave plasma as an adjunct therapy for wound healing in dogs and cats

  • Jisu Yoo;Yeong-Hun Kang;Seung Joon Baek;Cheol-Yong Hwang
    • Journal of Veterinary Science
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    • v.24 no.4
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    • pp.56.1-56.13
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    • 2023
  • Background: Cold atmospheric plasma is a novel innovative approach for wound care, and it is currently underrepresented in veterinary medicine. Objectives: To investigate the efficacy and safety of using cold atmospheric microwave plasma (CAMP) as an adjunct therapy for wound healing in dogs and cats. Methods: Wound healing outcomes were retrospectively analyzed using clinical records of client-owned dogs and cats who were first managed through standard wound care alone (pre-CAMP period) and subsequently via CAMP therapy (CAMP period). The degree of wound healing was estimated based on wound size and a modified wound scoring system. Results: Of the 27 acute and chronic wounds included in the analysis, 81.48% showed complete healing after the administration of CAMP as an adjunct therapy to standard care. Most wounds achieved complete healing in < 5 weeks. Compared with the pre-CAMP period, the rate of wound healing significantly increased every week in the CAMP period in terms of in wound size (first week, p < 0.001; second week, p = 0.012; third week, p < 0.001) and wound score (first week, p < 0.001; second week, p < 0.001; third week, p = 0.001). No adverse events were noted except for mild discomfort and transient erythema. Conclusions: CAMP is a well-tolerated therapeutic option with immense potential to support the treatment of wounds of diverse etiology in small animal practice. Further research is warranted to establish specific criteria for CAMP treatment according to wound characteristics.

The Character of Electron Ionization and Attachment Coefficients in Perfluoropropane(C3F8) Molecular Gas by the Boltzmann Equation (볼츠만 방정식에 의한 C3F8분자가스의 전리 및 부착 계수에 관한 연구)

  • Song, Byoung-Doo;Jeon, Byoung-Hoon;Ha, Sung-Chul
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.18 no.4
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    • pp.375-380
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    • 2005
  • CF₄ molecular gas is used in most of semiconductor manufacture processing and SF/sub 6/ molecular gas is widely used in industrial of insulation field. but both of gases have defect in global warming. C₃F/sub 8/ gas has large attachment cross-section more than these gases, moreover GWP, life-time and price of C₃F/sub 8/ gas is lower than them, therefor it is important to calculate transport coefficients of C₃F/sub 8/ gas like electron drift velocity, ionization coefficient, attachment coefficient, effective ionization coefficient and critical E/N. The aim of this study is to get these transport coefficients for imformation of the insulation strength and efficiency of etching process. In this paper, we calculated the electron drift velocity (W) in pure C₃F/sub 8/ molecular gas over the range of E/N=0.1∼250 Td at the temperature was 300 K and gas pressure was 1 Torr by the Boltzmann equation method. The results of this paper can be important data to present characteristic of gas for plasma etching and insulation, specially critical E/N is a data to evaluate insulation strength of a gas.

Emission Properties of Electrodeless Sulfur Lamp by Additives (화합물 첨가에 따른 무전극 황램프의 발광특성)

  • Lee, Jong-Chan;Kim, Kwang-Soo;Park, Dae-Hee;Hwang, Myung-Keun;Park, Cheol-Soon
    • Proceedings of the KIEE Conference
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    • 2002.07c
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    • pp.1890-1892
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    • 2002
  • The technology of sulfur lamps that has physical and electrical characteristics comparable to current HID source has been reported. The fundamental principles of the operation of microwave discharges that are used to convert microwave energy to broad spectrum visual light are known. In this paper, emission dependance of microwave discharges in mixture content of sulfur with noble gases was studied. It is shown that the excitation of this gaseous mixture is carried out in two phases: (l) ionization of noble gas atoms by a microwave field and (2) the consequent maintenance of slightly ionized nonequilibrium plasma by the field. These two processes have essentially various thresholds for the microwave pump. The purpose of this work is to investigate spectral properties of the high frequency discharges in a mixture sulfur vapors with noble gases.

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Friction and Wear of Nitrogen Incorporated Diamond-like Carbon Films Under a Vacuum

  • Yoon, Eui-Sung;Kong, Hosung;Lee, Kwang-Ryeol;Oh, Jae-Eung
    • Tribology and Lubricants
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    • v.11 no.5
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    • pp.59-65
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    • 1995
  • Tribological behaviors of nitrogen incorporated amorphous diamond-like carbon films were experimentally measured under a vacuum ($3 \times 10^{-5}$ Torr) using a ball (AISI 52100 steel)-on-disk wear-rig. Nitrogen incorporated DLC films were deposited by r.f. plasma assisted chemical vapor deposition method. Mixtures of benzene and ammonia or nitrogen gases were used as the reaction gases for the r.f. PACVD, and Si (100) wafer was used as the substrate. In the tribo-test, effects of DLC film thickness and normal load in friction were measured and discussed. Results showed that friction of nitrogen incorporated DLC films from a mixture gas of benzene and ammonia was lower than that of 100% benzene, specially in the measurement of minimum coefficient of friction. Differences in frictional characteristics of nitrogen incorporated DLC films were explained with the changes in chemical structures of the films. Result also showed that friction of DLC films increased with the sliding contact cycle, which remarkably accompanied with roll-shaped wear debris. Mechanisms and roles of the polymer-like wear debris were presented and discussed.

Charicteristics of HF 10-cm Type Grid Ion Source for Inert and Chemically Reactive Gases.

  • Chol, W.K;Koh, S.K;Jang, H.G;Jung, H.J;Kondranin, S.G.;Kralkina, E.A.;Bougrov, G.E.
    • Proceedings of the Korean Vacuum Society Conference
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    • 1996.02a
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    • pp.102-102
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    • 1996
  • This paper represents a new type low power High Frequency technological ion source (HF TIS) for ion - beam processing: the surface modification of materials, cleaning of surface, sputtering, coating of thin films, and polishing. The operational principle of HF TIS is based on the excitation of electrostatic waves in plasma located in the external magnetic field. Low power HF TIS with diameter 92 rom gives the opportunity to obtain beams of inert and chemically reactive gases with currents range from 5 to 150 mA (current density $0.015\;~\;3.5\;mA/\textrm{m}^2$) and ion beam energy 100 ~ 2500 eV at a HF power level 10 ~ 150 W. Three grid concave type ion optical system (IOS) is used for extraction and formation ofion beam.n beam.

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Cyclic on/off Modulation of $CH_4\;and/or\;O_2$ Flows for the Enhancement of the Diamond Film Characteristics ($CH_4/O_2$의 사이클릭 유량제어에 의한 다이아몬드 박막의 특성향상)

  • Kim Tae-Gyu;Kim Sung-Hoon;Yoon Su-Jong
    • Journal of the Korean institute of surface engineering
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    • v.39 no.2
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    • pp.82-86
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    • 2006
  • Diamond films were deposited on 10.0$\times$10.0$mm^2$ pretreated (100) Si substrate using $CH_4$, $H_2$ and $O_2$ source gases in a horizontal-type microwave plasma enhanced chemical vapor deposition system. We introduced a cyclic on/off modulation of $CH_4$ and/or $O_2$ flows is a function of the reaction time during the initial deposition stage. Surface morphology and diamond quality of the films were investigated as a function of the different cyclic modulation process of the source gases flows: For the enhancement of the nucleation density, there is an optimal process for the incorporation of oxygen. Diamond qualities of the films were improved by introducing oxygen gas during the initial deposition stage.

Application of Computational Fluid Dynamic Simulation to SiC CVD Reactor for Mass Production (대량 생산용 SiC CVD 리엑터에의 전산유체역학 시뮬레이션의 적용)

  • Seo, Jin-Won;Choi, Kyoon
    • Journal of the Korean Ceramic Society
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    • v.50 no.6
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    • pp.533-538
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    • 2013
  • Silicon carbide (SiC) materials are typical ceramic materials with a wide range of uses due to their high hardness and strength and oxidation resistance. In particular, due to the corrosion resistance of the material against acids and bases including the chemical resistance against ionic gases such as plasma, the application of SiC has been expanded to extreme environments. In the SiC deposition process, where chemical vapor deposition (CVD) technology is used, the reactions between the raw gases containing Si and C sources occur from gas phase to solid phases; thus, the merit of the CVD technology is that it can provide high purity SiC in relatively low temperatures in comparison with other fabrication methods. However, the product yield rarely reaches 50% due to the difficulty in performing uniform and dense deposition. In this study, using a computational fluid dynamics (CFD) simulation, the gas velocity inside the reactor and the concentration change in the gas phase during the SiC CVD manufacturing process are calculated with respect to the gas velocity and rotational speed of the stage where the deposition articles are located.

Plasma Etching Process based on Real-time Monitoring of Radical Density and Substrate Temperature

  • Takeda, K.;Fukunaga, Y.;Tsutsumi, T.;Ishikawa, K.;Kondo, H.;Sekine, M.;Hori, M.
    • Proceedings of the Korean Vacuum Society Conference
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    • 2016.02a
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    • pp.93-93
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    • 2016
  • Large scale integrated circuits (LSIs) has been improved by the shrinkage of the circuit dimensions. The smaller chip sizes and increase in circuit density require the miniaturization of the line-width and space between metal interconnections. Therefore, an extreme precise control of the critical dimension and pattern profile is necessary to fabricate next generation nano-electronics devices. The pattern profile control of plasma etching with an accuracy of sub-nanometer must be achieved. To realize the etching process which achieves the problem, understanding of the etching mechanism and precise control of the process based on the real-time monitoring of internal plasma parameters such as etching species density, surface temperature of substrate, etc. are very important. For instance, it is known that the etched profiles of organic low dielectric (low-k) films are sensitive to the substrate temperature and density ratio of H and N atoms in the H2/N2 plasma [1]. In this study, we introduced a feedback control of actual substrate temperature and radical density ratio monitored in real time. And then the dependence of etch rates and profiles of organic films have been evaluated based on the substrate temperatures. In this study, organic low-k films were etched by a dual frequency capacitively coupled plasma employing the mixture of H2/N2 gases. A 100-MHz power was supplied to an upper electrode for plasma generation. The Si substrate was electrostatically chucked to a lower electrode biased by supplying a 2-MHz power. To investigate the effects of H and N radical on the etching profile of organic low-k films, absolute H and N atom densities were measured by vacuum ultraviolet absorption spectroscopy [2]. Moreover, using the optical fiber-type low-coherence interferometer [3], substrate temperature has been measured in real time during etching process. From the measurement results, the temperature raised rapidly just after plasma ignition and was gradually saturated. The temporal change of substrate temperature is a crucial issue to control of surface reactions of reactive species. Therefore, by the intervals of on-off of the plasma discharge, the substrate temperature was maintained within ${\pm}1.5^{\circ}C$ from the set value. As a result, the temperatures were kept within $3^{\circ}C$ during the etching process. Then, we etched organic films with line-and-space pattern using this system. The cross-sections of the organic films etched for 50 s with the substrate temperatures at $20^{\circ}C$ and $100^{\circ}C$ were observed by SEM. From the results, they were different in the sidewall profile. It suggests that the reactions on the sidewalls changed according to the substrate temperature. The precise substrate temperature control method with real-time temperature monitoring and intermittent plasma generation was suggested to contribute on realization of fine pattern etching.

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Deposition Characteristic of InNx Films by Reactive DC Magnetron Sputtering (반응성 직류 스퍼터법에 의한 질화 인듐 박막의 제막 특성)

  • 송풍근;류봉기;김광호
    • Journal of the Korean Ceramic Society
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    • v.40 no.8
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    • pp.739-745
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    • 2003
  • In $N_{x}$ films were deposited on soda-lime glass without substrate heating by reactive dc magnetron sputtering using indium (In) metal target. Depositions were carried out under various total gas pressures ( $P_{tot}$) of mixture gases (Ar+$N_2$ or He+$N_2$). He gas was introduced to $N_2$ gas in order to enhance the reactivity of nitrogen on film surface by the "penning ionization". Plasma impedance decreased greatly when 20% or more introduced the $N_2$ gas. This is due to the In $N_{x}$ layers formed on target surface because a secondary electron emission rate of InN is small compared with In metal. XRD patterns of the films revealed that <001> preferred oriented polycrystalline In $N_{x}$ films, where the crystallinity of the films was improved with decrease of $P_{tot}$ and with increase of $N_2$ flow ratio. The improvement of the crystallinity and stoichimetry of the In $N_{x}$ films were considered to be caused by an increase in the activated nitrogen radicals and also by an increase in the kinetic energy of sputtered In atoms arriving at growing film surface, which should enhance the chemical reaction and surface migration on the growing film surface, respectively. Furthermore, the films deposited using mixture gases of He+$N_2$ showed higher crystallinity compared with the film deposited by the mixture gases of Ar+$N_2$.$.EX>.

Decrease of Global Warming Effect During Dry Etching of Silicon Nitride Layer Using C3F6O/O2 Chemistries

  • Kim, Il-Jin;Moon, Hock-Key;Lee, Jung-Hun;Jung, Jae-Wook;Cho, Sang-Hyun;Lee, Nae-Eung
    • Proceedings of the Korean Vacuum Society Conference
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    • 2012.02a
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    • pp.459-459
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    • 2012
  • Recently, the discharge of global warming gases in dry etching process of TFT-LCD display industry is a serious issue because perfluorocarbon compound (PFC) gas causes global warming effects. PFCs including CF4, C2F6, C3F8, CHF3, NF3 and SF6 are widely used as etching and cleaning gases. In particular, the SF6 gas is chemically stable compounds. However, these gases have large global warming potential (GWP100 = 24,900) and lifetime (3,200). In this work, we chose C3F6O gas which has a very low GWP (GWP100 = <100) and lifetime (< 1) as a replacement gas. This study investigated the effects of the gas flow ratio of C3F6O/O2 and process pressure in dual-frequency capacitively coupled plasma (CCP) etcher on global warming effects. Also, we compared global warming effects of C3F6O gas with those of SF6 gas during dry etching of a patterned positive type photo-resist/silicon nitride/glass substrate. The etch rate measurements and emission of by-products were analyzed by scanning electron Microscopy (SEM; HITACI, S-3500H) and Fourier transform infrared spectroscopy (FT-IR; MIDAC, I2000), respectively. Calculation of MMTCE (million metric ton carbon equivalents) based on the emitted by-products were performed during etching by controlling various process parameters. The evaluation procedure and results will be discussed in detail.

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