• 한국전기전자재료학회논문지
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• 제22권7호
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• pp.595-601
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• 2009

For the silicon oxide $(SiO_x)$ films prepared by using the facing target sputtering (FTS) apparatus that was manufactured to enhance the preciseness of the fabricated thin-film and sputtering yield rate by forming a higher-density plasma in the electrical discharge space for using it as a thin-film passivation system for flexible organic light emitting devices (FOLEDs). The deposition characteristics were investigated under various process conditions, such as array of the cathode magnets, oxygen concentration$(O_2/Ar+O_2)$ introduced during deposition, and variations of distance between two targets and working pressure. We report that the optimum conditions for our FTS apparatus for the deposition of the $SiO_x$ films are as follows: $d_{TS}\;and\;d_{TT}$ are 90mm and 120mm, respectively and the maximum deposition rate is obtained under a gas pressure of 2 mTorr with an oxygen concentration of 3.3%. Under this optimum conditions, it was found that the $SiO_x$ film was grown with a very high deposition rate of $250{\AA}$/min by rf-power of $4.4W/cm^2$, which was significantly enhanced as compared with a deposition rate (${\sim}55{\AA})$/min) of the conventional sputtering system. We also reported that the FTS system is a suitable method for the high speed and the low temperature deposition, the plasma free deposition, and the mass-production.

• ETRI Journal
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• 제27권5호
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• pp.545-550
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• 2005

We have carried out the fabrications of a barrier layer on a polyethersulfon (PES) film and organic light emitting diode (OLED) based on a plastic substrate by means of atomic layer deposition (ALD). Simultaneous deposition of 30 nm $AlO_x$ film on both sides of the PES film gave a water vapor transition rate (WVTR) of $0.062 g/m^2/day (@38^{\circ}C,\;100%\;R.H.)$. Further, the double layer of 200 nm $SiN_x$ film deposited by plasma enhanced chemical vapor deposition (PECVD) and 20 nm $AlO_x$ film by ALD resulted in a WVTR value lower than the detection limit of MOCON. We have investigated the OLED encapsulation performance of the double layer using the OLED structure of ITO / MTDATA (20 nm) / NPD (40 nm) / AlQ (60 nm) / LiF (1 nm) / Al (75 nm) on a plastic substrate. The preliminary life time to reach 91% of the initial luminance $(1300 cd/m^2)$ was 260 hours for the OLED encapsulated with 100 nm of PECVD-deposited $SiN_x$ and 30 nm of ALD-deposited $AlO_x$.

• Journal of Information Display
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• 제5권3호
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• pp.30-34
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• 2004

Fabrications of barrier layer on a polyethersulfon (PES) film and OLED based on a plastic substrate by atomic layer deposition (ALD) have been carried out. Simultaneous deposition of 30 nm of $AlO_x$ film on both sides of PES film gave film MOCON value of 0.0615 g/$m^2$/day (@38$^{\circ}C$, 100 % R.H.). Moreover, the double layer of 200 urn $SiN_x$ film deposited by PECVD and 20 nm of $AlO_x$ film by ALD resulted in the MOCON value lower than the detection limit of MOCON. The OLED encapsulation performance of the double layer have been investigated using the OLED structure of ITO/MTDATA(20 nm)/NPD(40 nm)/AlQ(60 nm)/LiF(1 nm)/Al(75 nm) based on the plastic substrate. Preliminary life time to 91 % of initial luminance (1300 cd/$m^2$) was 260 hours for the OLED encapsulated with 100 nm of PECVD deposited $SiN_x$/30 nm of ALD deposited $AlO_x$.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2008년도 International Meeting on Information Display
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• pp.617-619
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• 2008

Inorganic-organic hybrid multilayers were formed on the plastic substrate to enhance the barrier properties of substrate to water vapor and oxygen transport. Plasma pretreatment of substrate with $Ar/O_2$ lead to adhesion improvement and the densification of inorganic layer on the substrates. Combination of $SiO_xN_y$ layer and silanenanoclay composite layer offered quite good barrier properties (WVTR and OTR) to PES substrate.

• 한국세라믹학회지
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• 제41권6호
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• pp.435-438
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• 2004

MOCVD is one of the major deposition techniques for Cu thin films and Ta-Si-N is one of promising barrier metal candidates for Cu with high thermal stability. Effects of hydrogen plasma pretreatment of the underlying Ta-Si-N film surface on the Cu nucleation in Cu MOCVD were investigated using scanning electron microscopy, X-ray photoelectron spectroscopy and Auger electron emission spectrometry analyses. Cu nucleation in MOCVD is enhanced as the rf-power and the plasma exposure time are increased in the hydrogen plasma pretreatment. The optimal plasma treatment process condition is the rf-power of 40 Wand the plasma exposure time of 2 min. The hydrogen gas flow rate in the hydrogen plasma pretreatment process does not affect Cu nucleation much. The mechanism through which Cu nucleation is enhanced by the hydrogen plasma pretreatment of the Ta-Si-N film surface is that the nitrogen and oxygen atoms at the Ta-Si-N film surface are effectively removed by the plasma treatment. Consequently the chemical composition was changed from Ta-Si-N(O) into Ta-Si at the Ta-Si-N film surface, which is favorable for Cu nucleation.

• 한국응용과학기술학회지
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• 제24권2호
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• pp.174-181
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• 2007

본 연구에서는 졸-겔 공법을 이용하여 가스 차단 특성을 갖는 $SiO_2/EVOH$(에틸렌 비닐알콜 공중합체) 하이브리드 물질을 제조하였다. 제조된 여러 조성의 하이브리드 졸을 표면 처리한 biaxially oriented polypropylene (BOPP) 기지재에 스핀 코팅 방식을 이용하여 코팅하였다. X선 회절 및 DSC 분석에 의해 하이브리드 내의 EVOH 상과 실리카 상 사이의 결합에 따른 결정화 거동의 변화를 조사하였다. 또한 $SiO_2/EVOH$ 하이브리드 겔의 모폴로지 관찰을 통하여, 100nm 이하의 실리카 입자들이 균열하게 분산된 매우 치밀한 상 미세구조를 갖는 하이브리드 물질을 제조하기 위해 필요한 Tetraethylorthosilicate (TEOS) 무기전구체의 최적 함량이 존재함을 알 수 있었다. 첨가된 TEOS 함량이 최적 함량보다 낮거나 높은 경우에는 큰 도메인의 입자 클러스터들이 형성되어 매우 불안정한 모폴로지를 나타내는 상분리 현상이 관찰되었다. 이러한 모폴로지 결과는 하이브리드 코팅 필름의 산소 투과도의 변화 결과와 일치하였는데, TEOS 함량이 0.01 - 0.02mol로 첨가되어 제조된 하이브리드로 코팅된 필름의 경우 매우 우수한 산소 차단 특성을 나타냈으며, 0.04mol 이상으로 첨가되었을 때는 상 분리 및 미세 균열 발생으로 인하여 그 차단 특성이 급격하게 감소하는 것으로 나타났다.

• 한국분말재료학회지
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• 제24권6호
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• pp.437-443
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• 2017

SiC-based composite materials with light weight, high durability, and high-temperature stability have been actively studied for use in aerospace and defense applications. Moreover, environmental barrier coating (EBC) technologies using oxide-based ceramic materials have been studied to prevent chemical deterioration at a high temperature of $1300^{\circ}C$ or higher. In this study, an ytterbium silicate material, which has recently been actively studied as an environmental barrier coating because of its high-temperature chemical stability, is fabricated on a sintered SiC substrate. $Yb_2O_3$ and $SiO_2$ are used as the raw starting materials to form ytterbium disilicate ($Yb_2Si_2O_7$). Suspension plasma spraying is applied as the coating method. The effect of the mixing method on the particle size and distribution, which affect the coating formation behavior, is investigated using a scanning electron microscope (SEM), an energy dispersive spectrometer (EDS), and X-ray diffraction (XRD) analysis. It is found that the originally designed compounds are not effectively formed because of the refinement and vaporization of the raw material particles, i.e., $SiO_2$, and the formation of a porous coating structure. By changing the coating parameters such as the deposition distance, it is found that a denser coating structure can be formed at a closer deposition distance.

• Korean Journal of Chemical Engineering
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• 제35권12호
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• pp.2452-2463
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• 2018

Surface treatment of sol-gel bioglass is required to increase its biomedical applications. In this study, a dielectric barrier discharge (DBD) plasma treatment in atmospheric pressure was performed on the surface of [$SiO_2-CaO-P_2O_5-B_2O_3$] sol-gel derived glass. The obtained bioglass was treated by plasma using discharge current 12 mA with an exposure period for 30 min. The type of discharge can be characterized by measuring the discharge current and applied potential waveform and the power dissipation. Apatite formation on the surface of the DBD-treated and untreated samples after soaking in simulated body fluid (SBF) at $37^{\circ}C$ is characterized by Fourier transform infrared spectroscopy (FTIR), X-Ray diffraction (XRD), inductively coupled plasma (ICP-OES) and scanning electron microscopy coupled with energy dispersive spectroscopy (SEM/EDS). We observed a marked increase in the amount of apatite deposited on the surface of the treated plasma samples than those of the untreated ones, indicating that DBD plasma treatment is an efficient method and capable of modifying the surface of glass beside effectively transforming it into highly bioactive materials.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2012년도 춘계학술발표회 논문집
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• pp.124-125
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• 2012

Korea institute of materials science (KIMS) use a linear deposition source called as a closed drift linear plasma source (CDLPS) as well as dual magnetron sputtering (DMS) to deposit SiOxCyHz films in $HMDSO/O_2$ plasma. The CDLPS generates linear plasma using closed drifting electrons and can reduce device degradations due to energetic ion bombardments on organic devices such as organic photovoltaic and organic light emission diode by controlling an ion energy. The deposited films are investigated by Fourier transform infrared (FT-IR) spectroscopy, X-ray photoelectron spectroscopy (XPS), and atomic force microscopy (AFM). Optical emission spectroscopy (OES) is used to measure relative radical populations of dissociation and recombination products such as H, CH, and CO in plasma. And SiOx film is applied to a barrier film on organic photovoltaic devices.

• 대한금속재료학회지
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• 제49권7호
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• pp.577-582
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• 2011

The newly developed ${\alpha}-case$ controlled mold material for Ti investment castings was suggested in this research. The $Al_2O_3$ mold containing interstitial $TiO_2$ and substitutional $Ti_3Al$ was manufactured by the reaction between $Al_2O_3$ and Ti. It is obvious that as the $TiO_2$ and $Ti_3Al$ content in the mold surface were increased, the depth of the interfacial reaction was significantly reduced. In addition, substitutional $Ti_5Si_3$ in the mold surface owing to the reaction between Ti and $SiO_2$ from the binder was effective for ${\alpha}-case$ reduction. Therefore, the ${\alpha}-case$ reduction was accomplished by the diffusion barrier effect of interstitial $TiO_2$, substitutional $Ti_3Al$ and $Ti_5Si_3$.