• Proceedings of the KIEE Conference
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• 1997.07d
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• pp.1430-1432
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• 1997

A solar cell conversion effiency was degraded by grain boundary effect in polycrystalline silicon. To reduce these effects of the grain boundaries, we investigated various influencing factors such as preferential chemical etching of grain boundaries, grid design, transparent conductive thin film, and top metallization along grain boundaries. Pretreatment in $N_2$ atmosphere and gettering by $POCl_3$ and Al were performed to obtain polycrystalline silicon of the reduced defect density. Structural, electrical, and optical properties of solar cells were characterized. Improved conversion efficiencies of solar cell were obtained by a combination of Al diffusion into grain boundaries on rear side, fine grid finger, top Yb metal grid on Cr thin film of $200{\AA}$ and buried contact metallization along grain boundaries.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.31 no.1
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• pp.37-42
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• 2021

The effect of chemical composition on the structural and thermal properties of TiZrN thin films was studied. As the Zr fraction in the deposited TixZr1-xN (x = 0.87, 0.82, 0.7, 0.6, and 0.28) increased, microstructural changes consisted of reduction in the grain size and a gradual transition from columnar structure to granular structure were observed. In addition, it was also confirmed that a gradual crystal phase transition from TiN to TiZrN has occurred as the Zr fraction increased up to 0.4. After heat treatment at 900℃, Ti0.82Zr0.18N and Ti0.7Zr0.3N layers were converted to a form in which rutile phase TiO2 and TiZrO4 oxides coexist, while Ti0.6Zr0.4N layer was converted to TiZrO4 oxide. Among the five compositions of TiZrN films, the Ti0.6Zr0.4N showed the best high temperature stability and produced a significant enhancement in the thermal oxidation resistance of Inconel 617 through suppressing the surface diffusion of Cr caused by thermal oxidation of the Inconel 617 substrate.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.31A no.10
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• pp.108-113
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• 1994

The characteristics of the oxidation prevention layers for the copper metallization were investigated. The thin films such as Cr, TiN and Al were used as the oxidation prevention layers for copper. Ultra thin aluminum films were found to prevent the oxidation of copper up to the highest oxidation annealing temperature among the barrier layers examined in this study. It was found that oxygen did not diffuse into copper through aluminum films because of the aluminum oxide layer formed on the aluminum surface and the ultra thin aluminum film could be a good oxidation barrier layer for the copper metallization.

• Korean Journal of Materials Research
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• v.14 no.9
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• pp.634-641
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• 2004

The photocatalytic performance of $TiO_2$ thin films coated on porous alumina balls using various aqueous $TiOCl_2$ solutions as starting precursors, to which 1.0 $mol\%$ transition metal ($Ni^{2+},\;Cr^{3+},\;Fe^{3+},\;Nb^{3+},\;and\;V^{5+}$) chlorides had been already added, has been investigated, together with characterizations for $TiO_2$ sols synthesized simultaneously in the same autoclave through hydrothermal method. The synthesized $TiO_2$ sols were all formed with an anatase phase, and their particle size was between several nm and 30 nm showing ${\zeta}-potential$ of $-25{\sim}-35$ mV, being maintained stable for over 6 months. However, the $TiO_2$ sol added with Cr had a much lower value of -potential and larger particle sizes. The coated $TiO_2$ thin films had almost the same shape and size as those of the sol. The pure $TiO_2$ sol showed the highest optical absorption in the ultraviolet light region, and other $TiO_2$ sols containing $Cr^{3+},\;Fe^{3+}\;and\;Ni^{2+}$ showed higher optical absorption than pure sol in the visible light region. According to the experiments for removal of a gas-phase benzene, the pure $TiO_2$ film showed the highest photo dissociation rate in the ultraviolet light region, but in artificial sunlight the photo dissociation rate of $TiO_2$ coated films containing $Cr^{3+},\;Fe^{3+}\;and\;Ni^{2+}$ was measured higher together with the increase of optical absorption by doping.

• Proceedings of the Materials Research Society of Korea Conference
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• 2003.03a
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• pp.126-126
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• 2003

유기트랜지스터에 관한 연구는 1980년 이후부터 시작되었으나 근래에 들어 전 세계적으로 본격적인 연구가 진행되고 있다. 제작공정이 간단하고 비용이 저렴하며 충격에 의해 깨지지 않고 구부리거나 접을 수 있는 전자 회로 기판이 미래의 산업에 필수적인 요소가 될 것으로 예상되고 있으며 이러한 요구를 충족시킬 수 있는 유기트랜지스터의 개발은 아주 중요한 연구분야로 대두되고 있다. 본 연구에서는 표면처리에 따른 contact angle, I-V 특성곡선, 표면 morphology 등의 결과로부터 dry cleaning 한 것이 wet cleaning한 것보다 왜 좋은지를 논하고자 한다. 먼저 N-type SiO$_2$ 기판을 이용하여 back면의 oxide층을 제거한 후, back gate용으로 사용하기 위하여 sputtering장치로 Au/Cr을 증차하였다. 그리고 기판에 앞면을 photolithography 공정을 이용하여 Au/Cr를 1000$\AA$ 증착 하여 source-, drain-eldctrode를 제조하였다. 그리고 SiO$_2$ 기판의 표면처리를 달리하여 그 위에 유기박막을 증착하여 특성을 비교하였다.

• Journal of Surface Science and Engineering
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• v.27 no.3
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• pp.158-165
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• 1994

Cu-Cr alloy thin film requires good quality of etching be used for TAB technology. The etched cross sec-tion was clean enough when the etching was performed in 0.1M $FeCl_3$ solution at $50^{\circ}C$. The etching rate was increased with the amount of $KMnO_4$. For enhanced profile of cross section and rate, the spray etchning was found to be superior compared to the immersion etching. A series of experiments were performed to improve the uniformity of the current distribution in electrodeposition onto the substrate with lithographic patterns. Copper was electrodeposited from quiescent-solution, paddle-agitated-solution, and air-bubbled-solution to in-vestigate the effect of the fluid flow. The thickness profile of the specimen measured by profilmetry has the non uniformity at feature scale in quiescent-solution, because of the longitudinal vortex roll caused by the natural convection. However, uniform thickness profile was achieved in paddle-agitated or air bubbled solu-tion.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.36D no.7
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• pp.17-25
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• 1999

Tungsten nitride($WN_x$) films were deposited by PECVD method on silicon nitride($WSi_3N_4$) substrate. The characteristics of $WN_x$ film were investigated with changing various processing parameters ; substrate temperature, gas flow rate, rf power, and different nitrogen sources. The nitrogen composition in $WN_x$ film varied from 0 to 45% according to the $NH_3$ and $N_2$ flow rate. The highest deposition rate of 160 nm/min was obtained for the $NH_3$ gas and relatively low deposition rate of $WN_x$ films were formed by $N_2$ gas. $WN_x$ films deposited on $WSi_3N_4$ substrate had higher deposition rate than that of TiN and Si substrates. The purity of $WN_x$ film were analyzed by AES and higher purity $WN_x$ films were deposited using $NH_3$ gas. The XRD analysis indicates a phase transition from polycrystalline tungsten(W) to amorphous tungsten nitride($WN_x$), showing improved etching profile of $WN_x$ films Thick $WN_x$ films were deposited on various substrates such as Tin, NiCr and Al and maximum thickness of $1.6 {\mu}m$ was obtained on the Al adhesion layer.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.6
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• pp.1099-1103
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• 2007

TFT's have been intensively researched for possible electronic and display applications. Through tremendous engineering and scientific efforts, a-Si:H TFT fabrication process was greatly improved. In this paper, the reason on defects occurring at a-Si:H TFT fabrication process is analyzed and solved, so a-Si:H TFT's yield is increased and reliability is improved. The a-Si:H TFT of this paper is inverted staggered type TFT. The gate electrode is formed by patterning with length of $8{\mu}m{\sim}16{\mu}m$ and width of $80{\sim}200{\mu}m$ after depositing with gate electrode (Cr). We have fabricated a-SiN:H, conductor, etch-stopper and photo-resistor on gate electrode in sequence, respectively. We have deposited n+a-Si:H, NPR(Negative Photo Resister) layer after forming pattern of Cr gate electrode by etch-slower pattern. The NPR layer by inverting pattern of upper Sate electrode is patterned and the n+a-Si:H layer is etched by the NPR pattern. The NPR layer is removed. After Cr layer is deposited and patterned, the source-drain electrode is formed. The a-Si:H TFT made like this has problems at photo-lithography process caused by remains of PR. When sample is cleaned, this remains of PR makes thin chemical film on surface and damages device. Therefor, in order to improve this problem we added ashing process and cleaning process was enforced strictly. We can estimate that this method stabilizes fabrication process and makes to increase a-Si:H TFT's yield.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2013.05a
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• pp.171-172
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• 2013

종래의 흑연 위주 연료전지 분리판 개발되어 최근 고분자 전해질 막 연료전지가 높은 전력, 낮은 배기 가스 배출, 낮은 작동 온도로 자동차 산업에서 상당한 주목을 받고 있다. 요구사항은 높은 전기 전도도, 높은 내식성, 낮은 가스 투과성, 낮은 무게, 쉬운 가공, 낮은 제조비용이다. Thin film Cr 장비로 저항가열 furnace, sputter 등이 사용된다. 연료전지 분리판의 고전도도, 내부식성 보호막의 고속 증착을 위한 새로운 증착원으로 스퍼터 - 승화형 소스의 가능성을 유도 결합 플라즈마에 금속 봉을 직류 바이어스 함으로써 시도하였다. 유도 결합 플라즈마를 이용하여 승화증착 시스템을 사용하여 OES(SQ-2000)와 QMS (CPM-300)를 사용하여 $N_2$ flow에 따른 유도 결합 플라즈마를 이용한 스퍼터-승화 증착 시스템을 사용하여도 균일한 공정을 하는 것을 확인 하였다.

• Journal of the Korean Vacuum Society
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• v.4 no.S1
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• pp.108-112
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• 1995

Copper and aluminum selective deposition using (hfac)Cu(VTMS) and DMEAA precursors were performed in a warm-wall low pressure chemical vapour deposition reactor. The films of Cu and AI deposited on Corning 7059 glass and quartz with pattern of Cr seed metal. Selective deposition can be achieved at a pressure range of from 10-1 to 10 torr and substrate temperature range of 150-25$0^{\circ}C$. Selective deposition of Cu and AI by CVD is one of candidate for gate material formation fo larger area and high resolution plat panel displays.