• Title, Summary, Keyword: Native Oxide

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Native Oxide Formations on (Al, Ga) As and (Cd, Mn)Te surfaces ((Al, Ga)As 와 (Cd, Mn)Te의 복합화합물 반도체표면에서의 자연 산화물의 형성)

  • 최성수
    • Journal of the Korean Vacuum Society
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    • v.5 no.1
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    • pp.6-13
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    • 1996
  • The kinetics of native oxide formation on the (Al, Ga)As and (Cd, Mn)Te have been studied by X-ray photoelectron spectroscopy(XPS) and Auger electron spectroscopy(AES). The regrowth of native oxide after 3keV Ar ion sputter etch and deionized water etch has been studied. The previous report exhibited that the native oxide on CdTe and GaAs can be removed completely by deionzied(DI) water only[1]. On the other hand, the airgrown native oxide on (Al, Ga)As become nonhomogeneous and the regrown native oxide on (Cd,Mn)Te can be partially removed.

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Effects of native oxide on Si substrates-As ion implanted on the formation of Ti-Silicides grown by RTP method (As Ion 주입된 Si 기판위의 native oxide가 RTP법으로 성장시킨 Ti-Silicides의 형성에 미치는 영향)

  • Chung, Ju-Hyuck;Choi, Jin-Seog;Paek, Su-Hyon
    • Proceedings of the KIEE Conference
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    • pp.319-323
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    • 1988
  • For finding the effects of As on $TiSi_2$ formation, sputter deposited Ti film on Si substrates implanted with various doses of As have been rapid thermal annealed in Ar atmosphere at temperatures of 600-900$^{\circ}C$ for 20 sec. The sheet resistance of Ti-Silicides was examined with 4-point probe, the thickness with ${\alpha}$-step, and the As dopant behavior in Si substrates with ASR. The thickness of Ti-Silicides decreased with increasing As doping, but Ti-Silicides sheet resistance increased with increasing it. However, the critical concentration effect reported by Park et al. was not observed. We observed that the thickness of native oxide increase with increasing As doping. Thus, we concluded that native oxide act as a "barrier" for the Si diffusion.

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A Study on the Removal of Native Oxide on a Silicon Surface Using UV-Excited $F_2/H_2$ (UV-excited $F_2/H_2$를 이용한 실리콘 자연산화막 제거에 관한 연구)

  • Choi, S.H.;Choi, J.S.;Kim, S.I.;Koo, K.W.;Chun, H.G.
    • Proceedings of the KIEE Conference
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    • pp.1528-1530
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    • 1997
  • As device size shrinks, contamination will increasingly affect the reliability and yield of device. Therefore, contaminants must be removed from the surfaces of Si wafers prior to each process. But it becomes out increasingly difficult to clean silicon surfaces with finer patterns by the conventional wet treatment because of the viscosity and surface tension of solutions. Hence, a damage less dry cleaning process is needed for the silicon surfaces. For the removal of Si native oxide by UV-enhanced dry cleaning. $F_2$ gas and $F_2/H_2$ mixed gas were applied. As a result of analysis, UV-enhnaced $F_2/H_2$ treatment is more suitable than UV-enhanced $F_2$ treatment for removal of native oxide on the surfaces of Si wafers.

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Effect of surface roughness on the quality of silicon epitaxial film grown after UV-irradiated gas phase cleaning

  • Kwon, Sung-Ku;Kim, Du-Hyun
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.9 no.5
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    • pp.504-509
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    • 1999
  • In-situ cleaning and subsequent silicon epitaxial film growth were performed in a load-locked reactor equipped with Hg-grid UV lamp and PBN heater to obtain the smooth and contaminant-free underlying surface and develop low-temperature epitaxial film growth process. The removals of organic and native oxide were investigated using UV-excited $O_2$ and $NF_{3}/H_{2}$, and the effect of the surface condition was examined on the quality of silicon epitaxial film grown at temperature as low as $750^{\circ}C$. UV-excited gas phase cleaning was found to be effective in removing the organic and native oxide successfully providing a smooth surface with RMS roughness of 0.5$\AA$ at optimal condition. Crystalline quality of epitaxial film was determined by smoothness of cleaned surface and the presence of native oxide and impurity. Crystalline defects such as dislocation loops or voids due to the surface roughness were observed by XTEM.

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Silver Ore and Floatation Products from the Bupyeong Mine (부평광산(富平鑛山)의 금광석(金鑛石)과 선광산물(選鑛産物))

  • Park, Hee-ln;Park, No Young;Suh, Kyu Shik
    • Economic and Environmental Geology
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    • v.19 no.2
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    • pp.85-96
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    • 1986
  • The Bupyeong Silver mine which is located approximately 35km west of Seoul is currently the leading silver producer in Korea. The deposits occur as stockwork deposits hosted in Jurassic pyroclastic rocks. Occurrences of ore deposits and mineral paragenesis suggest a division of mineralization into four stages: Stage I, deposition of iron oxide and base metal sulfides; Stage II, deposition of tin oxide and silverm inerals; stage III, deposition of native silver and other silver minerals; Stage IV, formation of pyrite bearing siderite veinlets, Silver minerals in ore are native silver, argentite, freibergite, pyrargyrite, canfieldite, polybasite, dyscrasite and Ag-Fe-S mineral. The most important silver mineral is native silver among them. Chemical composition of important silver minerals were determined by electron probe microanalyser. Assay, size and modal analyses for floatation products were carried out. In floatation products, relative proportion of native silver for total important silver minerals have following ranges: feed, 64.7 to 74.74 wt.%; A-cleaner concentrate, 80.58 to 98.79 wt.%; and final tailing, 28.12 to 72. 57 wt. %. Average degree of liberation for native silver in feed and A-cleaner concentrate are 60.49% and 77.57% respectively. Negative relationship can be recognized between native silver and argentite in their abundance and behavior in floatation precesses.

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Changes in the electrochemical properties of air-formed oxide film-covered AZ31 Mg alloy in aqueous solutions containing various anions

  • Fazal, Basit Raza;Moon, Sungmo
    • Proceedings of the Korean Institute of Surface Engineering Conference
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    • pp.96.2-96.2
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    • 2017
  • This research was conducted to investigate the electrochemical properties of the thin air-formed oxide film-covered AZ31 Mg alloy. In this work, native air-formed oxide films on AZ31 Mg alloy samples were prepared by knife-abrading method and the changes in the electrochemical properties of the air-formed oxide film were investigated in seven different electrolytes containing the following anions $Cl^-$, $F^-$, $SO{_4}^{2-}$, $NO_3{^-}$, $CH_3COO^-$, $CO{_3}^{2-}$ and $PO{_4}^{3-}$. It was observed from open circuit potential (OCP) transients that the potential initially decreased before gradually increasing again in the solutions containing only $CO{_3}^{2-}$ or $PO{_4}^{3-}$ ions, indicating the dissolution or transformation of the native air-formed oxide film into new more protective surface films. The Nyquist plots obtained from electrochemical impedance spectroscopy (EIS) showed that there was growth of new surface films with immersion time on the air-formed oxide film-covered specimens in all the electrolytes; the least resistive surface films were formed in fluoride and sulphate baths whereas the most protective film was formed in phosphate bath. The potentiodynamic polarization curves illustrated that passive behaviour of AZ31 Mg alloy under anodic polarization appears only in $CO{_3}^{2-}$ or $PO{_4}^{3-}$ ions containing solutions and at more than $-0.4V_{Ag/AgCl}$ in $F^-$ ion containing solution.

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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.

Low temperature growth of carbon nanotube by plasma enhanced chemical vapor deposition (PECVD) using nickel catalyst

  • Ryu, Kyoung-Min;Kang, Mih-Yun;Kim, Yang-Do;Hyeongtag-Jeon
    • Proceedings of the International Microelectronics And Packaging Society Conference
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    • pp.109-109
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    • 2000
  • Recently, carbon nanotube has been investigating for field emission display ( (FED) applications due to its high electron emission at relatively low electric field. However, the growing of carbon nanotube generally requires relatively high temperature processing such as arc-discharge (5,000 ~ $20,000^{\circ}C$) and laser evaporation (4,000 ~ $5,000^{\circ}C$) methods. In this presentation, low temperature growing of carbon nanotube by plasma enhanced chemical vapor deposition (PECVD) using nickel catalyst which is compatible to conventional FED processing temperature will be described. Carbon n notubes with average length of 100 run and diameter of 2 ~ $3\mu$ill were successfully grown on silicon substrate with native oxide layer at $550^{\circ}C$using nickel catalyst. The morphology and microstructure of carbon nanotube was highly depended on the processing temperature and nickel layer thickness. No significant carbon nanotube growing was observed with samples deposited on silicon substrates without native oxide layer. This is believed due to the formation of nickel-silicide and this deteriorated the catalytic role of nickel. The formation of nickel-silicide was confirmed by x-ray analysis. The role of native oxide layer and processing parameter dependence on microstructure of low temperature grown carbon nanotube, characterized by SEM, TEM XRD and R없nan spectroscopy, will be presented.

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Effect of Surface Pretreatment on Film Properties Deposited by Electro-/Electroless Deposition in Cu Interconnection (반도체 구리 배선공정에서 표면 전처리가 이후 구리 전해/무전해 전착 박막에 미치는 영향)

  • Lim, Taeho;Kim, Jae Jeong
    • Journal of the Korean Electrochemical Society
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    • v.20 no.1
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    • pp.1-6
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    • 2017
  • This study investigated the effect of surface pretreatment, which removes native Cu oxides on Cu seed layer, on subsequent Cu electro-/electroless deposition in Cu interconnection. The native Cu oxides were removed by using citric acid-based solution frequently used in Cu chemical mechanical polishing process and the selective Cu oxide removal was successfully achieved by controlling the solution composition. The characterization of electro-/electrolessly deposited Cu films after the oxide removal was then performed in terms of film resistivity, surface roughness, etc. It was observed that the lowest film resistivity and surface roughness were obtained from the substrate whose native Cu oxides were selectively removed.

Screening of Antioxidative Activities and Antiinflammatory Activities in Local Native Plants (국내자생식물 추출물의 항산화 및 항염 활성 탐색)

  • Kim, Han-Hyuk;Kwon, Joo-Hee;Park, Kwan-Hee;Kim, Manh-Heun;Oh, Myoeng-Hwan;Choe, Kang-In;Park, Sang-Hee;Jin, Hye-Young;Kim, Sung-Sik;Lee, Min-Won
    • Korean Journal of Pharmacognosy
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    • v.43 no.1
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    • pp.85-93
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    • 2012
  • 181 kinds of local native plants were selected by its anti-inflammatorial folk medicinal uses and evaluated it antioxidative and inhibitory activity of nitric oxide (NO) production in lipopolysaccharide (LPS)-induced 264.7 macrophage cells. Among the 181 kinds of plants, 99 species showed potent antioxidative activities and 20 extracts showed inhibitory activity towards nitric oxide production by more than 70% at a concentration of $100{\mu}g/mL$. Therefore, these plants should be considered promising candidates for the treatment of inflammatory diseases accompanying overproduction of NO.