• 멤브레인
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• 제23권2호
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• pp.136-143
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• 2013

최근 큰 각광을 받고 있는 표면개질소재 중 하나인 도파민은 알칼리 수용액상에서 자발적으로 반응이 진행되어 금속, 고분자 등 거의 모든 소재에 강하게 흡착되는 물질로 흡착 메커니즘 및 반응 후 최종구조에 관해 많은 논란이 있다. 기존의 도파민의 최종구조는 aryl-aryl 결합에 의한 고분자 구조가 제안되었지만, 본 연구에서는 구조분석을 통해 기존에 제안된 aryl-aryl 결합이 형성되지 않는 결과와 열적거동을 통해 고분자의 특징이 나타나지 않는 것을 확인하였으며, 기체투과거동을 통해 고분자와 같이 비다공성 코팅층을 형성하지 못하는 결과를 토대로, 도파민의 최종구조는 2차 결합에 의한 초분자 구조로 서로 응집되어 있는 것으로 판단된다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1998년도 제13차 학술회의논문집
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• pp.195-200
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• 1998

Since the neural network was introduced, significant progress has been made on data handling and learning algorithms. Currently, the most popular learning algorithm in neural network training is feed forward error back-propagation (FFEBP) algorithm. Aside from the success of the FFEBP algorithm, polynomial neural networks (PNN) learning has been proposed as a new learning method. The PNN learning is a self-organizing process designed to determine an appropriate set of Ivakhnenko polynomials that allow the activation of many neurons to achieve a desired state of activation that mimics a given set of sampled patterns. These neurons are interconnected in such a way that the knowledge is stored in Ivakhnenko coefficients. In this paper, the PNN model has been developed using the plasma enhanced chemical vapor deposition (PECVD) experimental data. To characterize the PECVD process using PNN, SiO$_2$films deposited under varying conditions were analyzed using fractional factorial experimental design with three center points. Parameters varied in these experiments included substrate temperature, pressure, RF power, silane flow rate and nitrous oxide flow rate. Approximately five microns of SiO$_2$were deposited on (100) silicon wafers in a Plasma-Therm 700 series PECVD system at 13.56 MHz.

• 한국전기전자재료학회논문지
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• 제27권8호
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• pp.510-515
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• 2014

Thin films of cubic $Na_{0.6}WO_3$, which is one of the sodium tungsten bronze, were fabricated by rf sputtering for the electrode applications in integrated sensors and actuators. A single-phase cubic $Na_{0.6}WO_3$ sputtering target of power type was prepared by conventional solid-state reaction. Thin films were deposited from the powder target, and the as-deposited films were amorphous, thus they annealed by tube furnace or RTP for crystallization. Thin films having cubic phase $Na_xWO_3$ were fabricated by the optimization of sputtering and post-annealing conditions, but single-phase cubic $Na_{0.6}WO_3$ thin films were not obtained. Although the films were not in single phase, they had good electrical conduction properties showing electrical resistivities of $10-4{\Omega}{\cdot}cm$ order.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 제38회 하계학술대회
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• pp.1371-1372
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• 2007

In this study, in order to confirm the application possibility to the molecular electronic device, morphlogical property of the Arachidic acid was investigated. We have investigated morphology by BAM image and AFM. ${\pi}$-A curves investigated surface pressure of this LB film from liquid to solid state ranged between 40 to 45 mN/m. BAM images investigated the different states of Arachidic Acid LB film. When the surface pressure reaches at 40 mN/m, the monolayer was deposited onto the hydrophilic glass substrates by Y-type deposition. We also investigated the frequency characteristics of LB modified glass by QCM. We investigated morphology of arachidic acid by AFM. As a result, we obtained the frequency characteristic and morphology of LB films from controlling the deposited layers.

• 대한금속재료학회지
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• 제47권5호
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• pp.316-321
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• 2009

Co nanoparticles on silica substrates were fabricated by inducing a thin-film dewetting through two different processes-furnace annealing and pulsed-laser annealing. The effects of annealing temperature, film thickness and laser energy density on dewetting morphology and mechanism were investigated. Co thinfilms with thicknesses between 3 to 15 nm were deposited using ion-beam sputtering, and then, in order to induce dewetting, thermally annealed in furnace at temperatures between 600 and $900^{\circ}C$. Some as-deposited films were irradiated using a Nd-YAG pulsed-laser of 266 nm wavelength to induce dewetting in liquid-state. Films annealed in furnace agglomerated to form nanoparticles above $700^{\circ}C$, and those average particle size and spacing were increased with an increase of film thickness. On the laser annealing process, above the energy density of $100mJ/cm^2$, metal films were completely dewetted and the agglomerated particles exhibited greater size uniformity than those on the furnace annealing process. A detailed dewetting mechanism underlaying both processes were discussed.

• 한국전기전자재료학회논문지
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• 제27권6호
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• pp.350-355
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• 2014

Bottom-gate tin oxide ($SnO_2$) thin film transistors (TFTs) were fabricated on $N^+$ Si wafers used as gate electrodes. 60-nm-thick $SnO_2$ thin films acting as active layers were sputtered on $SiO_2/Al_2O_3$ films. The $SiO_2/Al_2O_3$ films deposited on the Si wafers were employed for gate dielectrics. In order to increase the resistivity of the $SnO_2$ thin films, oxygen mixed with argon was introduced into the chamber during the sputtering. The mobility of $SnO_2$ TFTs was measured as a function of the flow ratio of oxygen to argon ($O_2/Ar$). The mobility variation with $O_2/Ar$ was analyzed through studies on crystallinity, oxygen binding state, optical properties. X-ray diffraction (XRD) and XPS (X-ray photoelectron spectroscopy) were carried out to observe the crystallinity and oxygen binding state of $SnO_2$ films. The mobility decreased with increasing $O_2/Ar$. It was found that the decrease of the mobility is mainly due to the decrease in the polarizability of $SnO_2$ films.

• 전자공학회논문지D
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• 제35D권7호
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• pp.72-78
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• 1998

This paper is focused on the fabrication of reliable novel antifuse, which could operate at low voltage along with the improvement in OFF and ON-state properties. The fabricated antifuse consists of Al/BaTi$_{2}$O$_{3}$/SiO$_{2}$/TiW-silicide structure. Through the systematic analyses for bottom metal and the intermetallic insulator, material and electri cproperties were investiaged. TiW-silicide as the bottom electrode had smooth surface with average roughness of 11.angs. at 10X10.mu.m$^{2}$ and was bing kept as-deposited SiO$_{2}$ film stable. Amorphous BaTi$_{2}$O$_{3}$ film as the another insulator was chosen because of its low breakdown strength (2.5MV/cm). breakdown voltage of antifuse is remarkably reduced by using BaTi$_{2}$O$_{3}$ film, and leakage current of that maintained low level due to the SiO$_{2}$ film. Low ON-resistance (46.ohm./.mu.m$^{2}$) and low programming voltage(9.1V) can be obtained in theses antifuses with 220.angs. double insulator layer and 19.6X10$^{-6}$ cm$^{2}$ area, while keeping sufficient OFF-state reliability (less than 1nA).

• Biotechnology and Bioprocess Engineering:BBE
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• 제6권3호
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• pp.183-188
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• 2001

The deposition behavior and photoelectric response characteristics of chlorophyll a(Chl a) monolayers and multilayers were investigated under various film fabrication conditions. Chl a LB films were deposited onto quartz and pretreated ITO glass substrates under several fabrication conditions, including surface pressure and number of layers. The absorption spectra of Chl a in a solution state and solid-like state (LB films) were fairly consistent with each other, and two absorption peaks were found at 678 and 438nm, respectively. The prepared Chl a LB films were set into an electrochemistry cell equipped with a Pt plate as the counter electrode, and the photoelectric response characteristics were obtained and analyzed relative to the light illumination. By considering the resulting photocurrents, the optimal fabrication conditions for Chl a LB films were determined as 20mN/m of surface pressure and 20 layers. The action spectrum of the Chl a LB films was obtained in the visible region, and was found to be in good agreement with the absorption spectrum. The possible application of the proposed system as a constituent of an artificial color recognition device was suggested based on combining with the photoelectric conversion property of another light-sensitive biological pigment.

• 한국전기전자재료학회논문지
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• 제29권7호
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• pp.394-399
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• 2016

The silicon dioxide ($SiO_2$) was deposited using various gas as oxygen and nitrous oxide ($N_2O$) in nowadays. In order to improve electrical characteristics and the interface state density ($D_{it}$) in low temperature, It was deposited with carbon dioxide ($CO_2$) and silane ($SiH_4$) gas by inductively coupled plasma chemical vapor deposition (ICP-CVD). Each $D_{it}$ of $SiO_2$ using $CO_2$ and $N_2O$ gas was $1.30{\times}10^{10}cm^{-2}{\cdot}eV^{-1}$ and $3.31{\times}10^{10}cm^{-2}{\cdot}eV^{-1}$. It showed $SiO_2$ using $CO_2$ gas was about 2.55 times better than $N_2O$ gas. After 10 years when the thin film was applied to metal/insulator/semiconductor(MIS)-nonvolatile memory(NVM), MIS NVM using $SiO_2$($CO_2$) on tunneling layer had window memory of 2.16 V with 60% retention at bias voltage from +16 V to -19 V. However, MIS NVM applied $SiO_2$($N_2O$) to tunneling layer had 2.48 V with 61% retention at bias voltage from +20 V to -24 V. The results show $SiO_2$ using $CO_2$ decrease the $D_{it}$ and it improves the operating voltage.

• 전자공학회논문지D
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• 제35D권3호
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• pp.39-45
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• 1998

SrBi$_{2}$Ta$_{2}$O$_{9}$ (SBT) ferroelectric thin films for nonvolatile memory were prepared on Pt/Ti/SiO$_{2}$/Si and RuO$_{2}$/SiO$_{2}$/Si substrates by RF magnetron sputtering. The dependences of crystalline and electrical properties on the lower electrode type(Pt and RuO$_{2}$) and the annealing temperatures were investigated. SBT films regardless of their electrode types showed typeical Bi layered peroviskite crystal structures. The crystalline quality of as-deposited SBT films was improved by the rapid thermal annealing at 650.deg. C for 30 sec. The remanetn polarization of 2Pr (Pr+-Pr-) of the annealed SBT films deposited on Pt/Ti/SiO$_{2}$/Si substrates were about 11 .mu.C/cm$^{2}$ and 3 .mu.C/cm$^{2}$, respectively. The leakage currents at 3 V bias voltage were about 0.8 .mu.A/cm$^{2}$ for SBT/ Pt/Ti/SiO$_{2}$/Si and about 1 .mu.A/cm$^{2}$ for SBT/RuO$_{2}$/SiO$_{2}$/Si sample. SBT films annealed at 650 .deg. C showed no degradation in Pr values after 10$^{11}$ polarization switching cycles, indicating good fatigue properties. In addition, for SBT samples deposited on Pt/Ti/SiO$_{2}$/Si, Pr values increased to more than that of initial state, suggesting the increament of leakage current caused by repeated polarization.