• Title/Summary/Keyword: Si nano-structure

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Effect of Post-CMP Cleaning On Electrochemical Characteristics of Cu and Ti in Patterned Wafer

  • Noh, Kyung-Min;Kim, Eun-Kyung;Lee, Yong-Keun;Sung, Yun-Mo
    • Korean Journal of Materials Research
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    • v.19 no.3
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    • pp.174-178
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    • 2009
  • The effects of post-CMP cleaning on the chemical and galvanic corrosion of copper (Cu) and titanium (Ti) were studied in patterned silicon (Si) wafers. First, variation of the corrosion rate was investigated as a function of the concentration of citric acid that was included in both the CMP slurry and the post-CMP solution. The open circuit potential (OCP) of Cu decreased as the citric acid concentration increased. In contrast with Cu, the OCP of titanium (Ti) increased as this concentration increased. The gap in the OCP between Cu and Ti increased as citric acid concentration increased, which increased the galvanic corrosion rate between Cu and Ti. The corrosion rates of Cu showed a linear relationship with the concentrations of citric acid. Second, the effect of Triton X-$100^{(R)}$, a nonionic surfactant, in a post-CMP solution on the electrochemical characteristics of the specimens was also investigated. The OCP of Cu decreased as the surfactant concentration increased. In contrast with Cu, the OCP of Ti increased greatly as this concentration increased. Given that Triton X-$100^{(R)}$ changes its micelle structure according to its concentration in the solution, the corrosion rate of each concentration was tested.

Tuning of Electro-optical Properties of Nano-structured SnO2:Ga Powders in a Micro Drop Fluidized Reactor

  • Lim, Dae Ho;Yang, Si Woo;Yoo, Dong June;Lee, Chan Gi;Kang, Yong
    • Korean Chemical Engineering Research
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    • v.57 no.2
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    • pp.259-266
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    • 2019
  • Tuning of electro-optical properties of nano-structured $SnO_2:Ga$ powders in a micro drop fluidized reactor (MDFR) was highly effective to enhance the activities of powders to be used as sensor materials. The tuning was conducted continuously in a facile one-step process during the formation of powders. The microscopic hydrodynamic forces affected the band gap structure and charge transfer of $SnO_2:Ga$ powders through the oxygen and interfacial tin vacancies by providing plausible pyro-hydraulic conditions, which resulted in the decrease in the electrical resistance of the materials. The analyses of room-temperature photoluminescence (PL) spectra and FT-IR exhibited that the tuning could improve the surface activities of $SnO_2:Ga$ powders by adjusting the excitation as well as separation of electrons and holes, thus maximizing the oxygen vacancies at the surface of the powders. The scheme of photocatalytic mechanism of $SnO_2:Ga$ powders was also discussed.

Application of Electron Energy Loss Spectroscopy - Spectrum Imaging (EELS-SI) for Microbe-mineral Interaction (생지구화학적 광물변이작용 연구에서 전자에너지 손실 분광 분석 - 스펙트럼 영상법의 활용)

  • Yang, Kiho;Park, Hanbeom;Kim, Jinwook
    • Journal of the Mineralogical Society of Korea
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    • v.32 no.1
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    • pp.63-69
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    • 2019
  • The oxidation states of structural Fe in minerals reflect the paleo-depositional redox conditions for the biologically or abiotically induced mineral formation. Particularly, nano-scale analysis using high-resolution transmission electron microscopy (HRTEM) and electron energy loss spectroscopy (EELS) is necessary to identify evidence for the microbial role in the biomineralization. HRTEM-EELS analysis of oxidation states of structural Fe and carbon bonding structure differentiate biological factors in mineralization by mapping the distribution of Fe(II)/Fe(III) and source of organic C. HRTEM-EELS technique provides geomicrobiologists with the direct nano-scale evidence of microbe-mineral interaction.

Formation of Bioactive Surface by PEO-treatment after 2nd ATO Technique of Ti-6Al-4V Alloy (Ti-6Al-4V 합금에 2nd ATO 처리 후 플라즈마 전해 산화법에 의한 생체활성표면형성)

  • Lim, Sang-Gyu;Cho, Han-Cheol
    • Proceedings of the Korean Institute of Surface Engineering Conference
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    • 2018.06a
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    • pp.74-74
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    • 2018
  • Ti-6Al-4V alloys have been widely used as orthopedic materials because of their excellent corrosion resistance and mechanical properties. However, it does not bind directly to the bone, so it requires a surface modification. This problem can be solved by nanotube and micropore formation. Plasma electrolytic oxidation (PEO) treatment for micropore, which combines high-voltage spark and electrochemical oxidation, is a new way of forming a ceramic coating on light metals such as titanium and its alloys. This method has excellent reproducibility and can easily control the shape and size of the Ti alloy. In this study, formation of bioactive surface by PEO-treatment after $2^{nd}$ ATO technique of Ti-6Al-4V alloy was invesgated by various instrument. Nanotube oxide surface structure was formed on the surface by anodic oxidation treatment in 0.8 wt.% NaF and 1M $H_3PO_4$ electrolytes. After nanotube formation, nanotube layer was removed by ultrasonic cleaning. PEO-treatment was carried out at 280V for 3 minutes in the electrolytic solution containing the bioactive substance (Mg, Zn, Mn, Sr, and Si). The surface of Ti-6Al-4V alloy was observed by field emission scanning electron microscopy (FE-SEM, S-4800 Hitachi, Japan). An energy dispersive X-ray spectrometer (EDS, Inca program, Oxford, UK) was used to analyze the spectra of physiologically active Si, Mn, Mg, Zn, and Sr ions. The PEO film formed on the Ti-6Al-4V alloy surface was characterized using an X-ray diffractometer (TF-XRD, X'pert Philips, Netherlands). It is confirmed that bioactive ions play an essential role in the normal bone growth and metabolism of the human skeletal tissues.

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Color Adjustment Study by Micro-Pattern Embedding in Optical Multilayer Thin Film (다층광학필름에서 마이크로패턴 삽입을 통한 색 조정 연구)

  • Kim, Min;Woo, Ju Yeon;Yoon, Junho;Hwangbo, Chang Kwon;Han, Chang-Soo
    • Journal of the Korean Society for Precision Engineering
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    • v.33 no.5
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    • pp.409-417
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    • 2016
  • It is well known that Morpho butterflies show distinctive, brilliant and iridescent colors and have micro-nano scale structures, instead of dyes and pigments, on their wings. This structural coloration is regarded as a novel technique to express color with a long lifetime, ease and precise tenability. Here, we studied optical multilayer thin films with thickness of several tens of nm ($TiO_2$ and $SiO_2$) and lens-shape micro-patterns. Fabrication and characterization of the multilayer stacking structure and the micro-pattern structure were performed and the films were analyzed via several optical measuring techniques. Finally, we discussed how the micro-pattern structure could enhance independence with color changes according to the viewing angle.

Study on Nucleation and Evolution Process of Ge Nano-islands on Si(001) Using Atomic Force Microscopy (AFM을 이용한 Si (001) 표면에 Ge 나노점의 형성과 성장과정에 관한 연구)

  • Park, J.S.;Lee, S.H.;Choia, M.S.;Song, D.S.;Leec, S.S.;Kwak, D.W.;Kim, D.H.;Yang, W.C.
    • Journal of the Korean Vacuum Society
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    • v.17 no.3
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    • pp.226-233
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    • 2008
  • The nucleation and evolution process of Ge nano-islands on Si(001) surfaces grown by chemical vapor deposition have been explored using atomic force microscopy (AFM). The Ge nano-islands are grown by exposing the substrates to a mixture of gasses GeH4 and H2 at pressure of 0.1-0.5Torr and temperatures of $600-650^{\circ}C$. The effect of growth conditions such as temperature, Ge thickness, annealing time on the shape, size, number density, and surface distribution was investigated. For Ge deposition greater than ${\sim}5$ monolayer (ML) with a growth rate of ${\sim}0.1ML/sec$ at $600^{\circ}C$, we observed island nucleation on the surface indicating the transition from strained layer to island structure. Further deposition of Ge led to shape transition from initial pyramid and hut to dome and superdome structure. The lateral average size of the islands increased from ${\sim}20nm$ to ${\sim}310nm$ while the number density decreased from $4{\times}10^{18}$ to $5{\times}10^8cm^{-2}$ during the shape transition process. In contrast, for the samples grown at a relatively higher temperature of $650^{\circ}C$ the morphology of the islands showed that the dome shape is dominant over the pyramid shape. The further deposition of Ge led to transition from the dome to the superdome shape. The evolution of shape, size, and surface distribution is related to energy minimization of the islands and surface diffusion of Ge adatoms. In particular, we found that the initially nucleated islands did not grow through long-range interaction between whole islands on the surface but via local interaction between the neighbor islands by investigation of the inter-islands distance.

The Study of Ni-Pd Alloy Characteristics to Form a NiSi for Shallow S/D Junction (Shallow S/D Junction에 적용 가능한 NiSi를 형성하기 위한 Ni-Pd 합금의 특성 연구)

  • Lee, Won-Jae;Oh, Soon-Young;Agchbayar, Tuya;Yun, Jang-Gn;Kim, Yong-Jin;Zhang, Ying-Ying;Zhong, Zhun;Kim, Do-Woo;Cha, Han-Seob;Heo, Sang-Bum;Wang, Jin-Suk;Lee, Hi-Deok
    • Proceedings of the IEEK Conference
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    • 2005.11a
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    • pp.603-606
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    • 2005
  • In this paper, the formation and thermal stability of Ni-silicide using Ni-Pd alloys is studied for ultra shallow S/D junction of nano-scale CMOSFETs. There are no different effects when Ni-Pd is used in single structure and TiN capping structure. But, in case of Cobalt interlayer structure, it was found that Pure Ni had lower sheet resistance than Ni-Pd, because of a thick silicide. Also, Ni-Pd has merits that surface of silicide and interface between silicide and silicon have a good morphology characteristics. As a result, Ni-Pd is an optimal candidate for shallow S/D junction when cobalt is used for thermal stability.

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Polymer-based Large Core Optical Splitter for Multimode Optical Networks (멀티모드 광네트워크용 폴리머기반 대구경 광분배기)

  • An, Jong Bae;Lee, Woo-Jin;Hwang, Sung Hwan;Kim, Gye Won;Kim, Myoung Jin;Jung, Eun Joo;Moon, Jong Ha;Kim, Jin Hyeok;Rho, Byung Sup
    • Korean Journal of Optics and Photonics
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    • v.24 no.4
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    • pp.184-188
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    • 2013
  • Two types of polymer-based optical splitters with $200{\mu}m$ large core are presented for optical multimode networks, such as smart home networks, intelligent automotive networks, etc. Optical splitters that have 1:1 symmetric and 9:1 asymmetric structure were fabricated by a ultra violet(UV)-imprint technology using a deep etched Si(silicon) master by the Bosch process. In this paper, we successfully fabricated the symmetric and asymmetric optical splitters with suitable optical network applications.

Analysis of Increasing the Conduction of V2O5 Thin Film on SiO2 Thin Film (SiO2 절연박막에 의해서 바나듐옥사이드 박막이 전도성이 높아지는 원인분석)

  • Oh, Teresa
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.19 no.8
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    • pp.14-18
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    • 2018
  • Generally. the Ohmic's law is an important factor to increase the conductivity in a micro device. So it is also known that the Ohmic contact in a semiconductor device is import. The PN junction as a structure of semiconductor involves the depletion layer, and this depletion layer induces the non linear electrical properties and also makes the Schottky contact as an intrinsic characteristics of semiconductor. To research the conduction effect of insulators in the semiconductor device, $SiO_2$ thin film and $V_2O_5/SiO_2$ thin film were researched by using the current-voltage system. In the nano electro-magnetic system, the $SiO_2$ thin film as a insulator had the non linear Schottky contact, and the as deposited $V_2O_5$ thin film had the linear Ohmic contact owing to the $SiO_2$ thin film with superior insulator's properties, which decreases the leakage current. In the positive voltage, the capacitance of $SiO_2$ thin film was very low, but that of $V_2O_5$ thin film increased with increasing the voltage. In the normal electric field system, it was confirmed that the conductivity of $V_2O_5$ thin film was increased by the effect of $SiO_2$ thin film. It was confirmed that the Schottky contact of semiconductors enhanced the performance of electrical properties to increased the conductivity.

A study on the structure of Si-O-C thin films with films size pore by ICPCVD (ICPCVD방법에 의한 나노기공을 갖는 Si-O-C 박막의 형성에 관한 연구)

  • Oh, Teresa
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2002.11a
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    • pp.477-480
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    • 2002
  • Si-O-C(-H) thin film with a tow dielectric constant were deposited on a P-type Si(100) substrate by an inductively coupled plasma chemical vapor deposition (ICPCVD). Bis-trimethylsilymethane (BTMSM, H$_{9}$C$_3$-Si-CH$_2$-Si-C$_3$H$_{9}$) and oxygen gas were used as Precursor. Hybrid type Si-O-C(-H) thin films with organic material have been generated many voids after annealing. Consequently, the Si-O-C(-H) films can be made a low dielectric material by the effect of void. The surface characterization of Si-O-C(-H) thin films were performed by SEM(scanning electron microscope). The characteristic analysis of Si-O-C(-H) thin films were performed by X-ray photoelectron spectroscopy (XPS).

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