• 한국세라믹학회지
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• 제33권7호
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• pp.761-770
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• 1996

Silicon carbide (SiC) films were deposited by low pressure chemical vapor deposition (LPCVD) using MTS (CH3SICl3) in a hydrogen atmosphere onto graphite substrates. Depletion effects of reactants which usually occur in the hot wall horizaontal reactor were increased with deposition temperature and pressure. Below 50 torr of total pressure (111) plane was preferenctially grown irrespectrive of deposition temperature and deposition site. Over 50 torr of total pressure however (220) plane was preferentially deposited under 130$0^{\circ}C$ and at inlet site. The surface morphologies of SiC films were uniform at all deposition sites under low pressure but greatly changed with pressure. It shows that a facet structure which was formed above 125$0^{\circ}C$ played an important role in the changed of preferred orientation and surface roughness.

• 전기화학회지
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• 제25권4호
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• pp.134-153
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• 2022

리튬이온전지의 에너지밀도가 지속적으로 높아지고 사용환경이 가혹해지고 있지만, 전지의 안전성은 타협할 수 있는 특성이 아니다. 특히, 더 높은 에너지밀도 확보를 위해 고용량 전극 소재 개발과 함께 분리막 원단 뿐만 아니라 세라믹 코팅층의 두께 및 무게의 박막화와 경량화가 동시에 요구되고 있다. 그 중, 기존 슬러리 코팅 방식을 증착 방식으로 대체하는 기술이 주목받고 있으며, 분리막의 내열성 확보를 위해 도입된 수 ㎛ 수준의 세라믹 코팅층을 nm 수준으로 박막/경량화 하면서도 동등의 내열성을 확보하는 시도가 진행되고 있다. 증착법으로 제조된 세라믹 코팅 분리막은 리튬이온전지 에너지밀도를 크게 증가시킬 수 있는 효율적인 방법이지만, 균일한 물성의 세라믹 코팅 분리막을 제작하기 위해서는 증착 공정 중 온도를 제어해야 하며, 생산속도와 공정비용을 기존 슬러리 코팅 수준으로 떨어뜨려야 하는 현실적 문제가 존재한다. 그럼에도 불구하고, 분리막 원단 대비 두께 및 무게 증가가 거의 없다는 점에서는 전지의 고에너지밀도 달성에 필요한 매력적인 접근법임은 분명하다. 본 총설에서는 세라믹 증착 코팅에 사용되고 있는 세 가지 방법인 1) 화학적 기상 증착법, 2) 원자층 증착법, 그리고 3) 물리적 기상 증착법으로 제조된 세라믹 코팅 분리막을 소개하고자 한다. 각 증착법의 원리와 장/단점을 설명하고, 제조된 세라믹 코팅 분리막의 물리적, 전기화학적 특성 및 전지의 성능 변화를 비교 분석하였다. 또한, 소재 관점에서 금속 또는 유기물질이 코팅된 초박막 코팅 분리막의 기술 동향도 소개하였다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 1999년도 제17회 학술발표회 논문개요집
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• pp.98-98
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• 1999

Highly transparent and conducting tin-doped indium oxide (ITO) films were deposited on polycarbonate substrate by ion-assited deposition. Low substrate temperature (<10$0^{\circ}C$) was maintained during deposition to prevent the polycarbonate substrate from be deformed. The influence of ion beam energy, ion current density, and tin doping, on the structural, electrical and optical properties of deposited films was investigated. Indium oxide and tin-doped indium oxide (9 wt% SnO2) sources were evaporated with assisting ionized oxygen in high vacuum chamber at a pressure of 2$\times$10-5 torr and deposition temperature was varied from room temperature to 10$0^{\circ}C$. Oxygen gas was ionized and accelerated by cold hallow-cathode type ion gun at oxygen flow rate of 1 sccm(ml/min). Ion bea potential and ion current of oxygen ions was changed from 0 to 700 V and from 0.54 to 1.62 $\mu$A. The change of microstructure of deposited films was examined by XRD and SEM. The electrical resistivity and optical transmittance were measured by four-point porbe and conventional spectrophotometer. From the results of spectrophotometer, both the refractive index and the extinction coefficient were derived.

• 한국세라믹학회지
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• 제41권9호
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• pp.637-641
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• 2004

We investigated the effects of SiH$_4$ gas on the surface of Hf-silicate films during the deposition of polycrystalline (poly) Si films and the thermal stability of sputtered Hf-silicate films in poly Si/Hf-silicate structure by using High Resolution Transmission Electron Microscopy (HR-TEM) and X-ray Photoelectron Spectroscopy (XPS). Hf-silicate films were deposited by using DC-mag-netron sputtering with Hf target and Si target and poly Si films were deposited at 600$^{\circ}C$ by using Low Pressure Chemical Vapor Deposition (LPCVD) with SiH$_4$ gas. After poly Si film deposition at 600$^{\circ}C$, Hf silicide layer was observed between poly Si and Hf-silicate films due to the reaction between active SiH$_4$ gas and Hf-silicate films. After annealing at 900$^{\circ}C$, Hf silicide, formed during the deposition of poly Si, changed to Hf-silicate and the phase separation of the silicate was not observed. In addition, the Hf-silicate films remain amorphous phase.

• 한국세라믹학회지
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• 제43권4호
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• pp.199-202
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• 2006

In this study, SiC whiskers were grown on a porous SiC diesel particulate filter for nanoparticle filtering. To grow the whiskers at the inner pore without closing the pores, we used chemical vapor infiltration with a solution source and a dilute. As the deposition time increased, the whiskers grew and formed a network structure. After 180 min of deposition, the mean diameter of the whiskers was 174 nm and the compressive strength was 58.4 MPa. The pores shrank from $10{\mu}m\;to\;0.4{\mu}m$ and, because the whiskers filed the inner pores, the gradient of permeability decreased as the deposition time increased. However, by using the network structure of whiskers deposited for 120 min and 180 min, we obtained a diesel particulate filter with pores of $0.98{\mu}m\;and\;0.4{\mu}m$, respectively. Furthermore, the filter shows better permeability than a porous body with pores of $1{\mu}m$. In short, by filtering the nanoparticulate materials, the network structure of whiskers improves the strength, reduces the pore size and minimizes the permeability drop.

• 한국분말재료학회지
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• 제20권6호
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• pp.460-466
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• 2013

4 mol% Yttria-stabilized zirconia (4YSZ) coatings with $200{\mu}m$ thick are fabricated by Electron Beam Physical Vapor Deposition (EB-PVD) for thermal barrier coating (TBC). $150{\mu}m$ of NiCrAlY based bond coat is prepared by conventional APS (Air Plasma Spray) method on the NiCrCoAl alloy substrate before deposition of top coating. 4 mol% YSZ top coating shows typical tetragonal phase and columnar structure due to vapor phase deposition process. The adhesion strength of coating is measured about 40 MPa. There is no delamination or cracking of coatings after thermal cyclic fatigue and shock test at $850^{\circ}C$.

• 한국세라믹학회지
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• 제49권6호
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• pp.663-668
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• 2012

In order to reduce the indium contents in transparent conducting oxide(TCO) thin films of $In_{1.6{\sim}1.8}Zn_{0.2}Sn_{0.2{\sim}0.4}O_3$ (IZTO), $In_{1.6}Zn_{0.2}Sn_{0.2}O_{3-{\delta}}$(IZTO) was prepared by replacing indium with Zn and Sn. The TCO films were deposited via RF-magnetron sputtering of the IZTO target at various deposition temperatures and its film characteristics were investigated. When deposited in an Ar atmosphere at $400^{\circ}C$, the electrical resistivity of the film decreased to $6.34{\times}10^{-4}{\Omega}{\cdot}cm$ and the optical transmittance was 80%. As the deposition temperature increased, the crystallinity of the IZTO film was enhanced. As a result, the electrical conductivity and transmittance properties were improved. This demonstrates the possibility of replacing ITO TCO film with IZTO.

• 한국세라믹학회지
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• 제51권3호
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• pp.177-183
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• 2014

Alumina-silica composite coating layers were prepared by electrophoretic deposition (EPD) of plate-shaped alumina particles dispersed in a sol-gel binder, which was prepared by hydrolysis and the condensation reaction of methyltrimethoxysilane in the presence of colloidal silica. The microstructure and the electrical and thermal properties of the coatings were compared according to the EPD process parameter: voltage, time and the content of the plate-shaped alumina particles. The electrical insulation property of the coatings was measured by a voltage test. The coatings were prepared by EPD of the sol-gel binder with 5-30 wt% plate alumina particles on parallel electrodes at a distance of 2 cm for 1-10 min under an applied voltage of 10-30 V. The coatings experienced increased breakdown voltage with increasing thickness. However, the higher the thickness was, the smaller the breakdown voltage strength was. A breakdown voltage as high as 4.6 kV was observed with a $400{\mu}m$ thickness, and a breakdown voltage strength as high as 27 kV/mm was achieved for the sample under a $100{\mu}m$ thickness.

• 한국세라믹학회지
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• 제31권3호
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• pp.257-264
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• 1994

The objectives of this study were to develop the low pressure chemical vapor deposition(LPCVD) process of SiC and to fabricate pure and dense SiC layer onto graphite substrate at low temperature. The deposition experiments were performed using the MTS-H2 system (30 torr) in the deposition temperature ranging from 100$0^{\circ}C$ to 120$0^{\circ}C$. The deposition rate of SiC was increased with the temperature. The rate controlling step can be classified from calculated results of the apparent thermal activation energy as follows; surface reaction below 110$0^{\circ}C$ and gas phase diffusion through a stagnant layer over 110$0^{\circ}C$. The deposited layer was $\beta$-SiC with a preferred orientation of (111) and the strongly faceted SiC deposits were observed over 115$0^{\circ}C$.

• 한국세라믹학회지
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• 제28권10호
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• pp.777-784
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• 1991

Diamond films have been growth by the hot-filament chemical vapor deposition (HFCVD) using CH4 and H2 gaseous mixture on the Si substrate. The experimental results indicated that the deposits were pure diamond and contained no amount of non-diamond phases such as amorphous carbon or graphite. The diamond films were deposited well at the conditions: the filament temperature of 210$0^{\circ}C$, the substrate temperature of 77$0^{\circ}C$, the CH4 concentration of 1.76%, the reactor pressure of 30 torr, and the deposition time of 7 hr. At this growth condition, the maximum deposition rate was 2 ${\mu}{\textrm}{m}$/hr. X-ray diffraction patterns and texture coefficient results showed that preferred orientation of the diamond films was {111} orientation under all experimental conditions.