• 반도체디스플레이기술학회지
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• 제18권4호
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• pp.149-153
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• 2019

The technology of electronic packaging among semiconductor technologies is evolving as an axis of the market in its own field beyond the simple assembly process of the past. In the field of electronic packaging technology, the packaging of power modules plays an important role for green electric vehicles. In this power module packaging, the thermal reliability is an important factor, and silicon nitride plays an important part of package substrates, Silicon nitride is a compound that is not found in nature and is made by chemical reaction between silicon and nitrogen. In this study, this core material, silicon nitride, was fabricated by reaction bonded silicon nitride. The fabricated silicon nitride was studied for thermo-mechanical properties, and through this, the structure of power module packaging was made using reaction bonded silicon nitride. And the characteristics of stress were evaluated using finite element analysis conditions. Through this, it was confirmed that reaction bonded silicon nitride could replace the silicon nitride as a package substrate.

• 농업과학연구
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• 제39권4호
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• pp.591-594
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• 2012

Effect of pulsed power was investigated on fruit body formation of 10 edible mushrooms, Lentinula edodes, Glifola frondosa, Pholiota nameko, Flammulina velutipes, Hypsizygus marmoreus, Pleurotus ostreatus, Pleurotus eryngii, Pleurotus abalonus, Agrocybe cylindracea and Sparassis crispa. Pulsed power of 100-170 kV was directly charged to the substrate just before fructification. The effect of the pulsed power resulted to promote for 10 edible mushrooms fructification. The treatment especially stimulated the fructification on Pleurotus species.

• 한국진공학회지
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• 제2권3호
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• pp.346-354
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• 1993

고주파플라즈마 CVD법으로 CH4와 H2의 혼합가스로부터 실리콘과 석영기판 위에 다이아몬드 입자와 박막을 성장시켰다. 기판과 기판지지대 사이에 금속판을 삽입함으로써 기판의 온도와 성장된 박막의 두께를 비교적 균일하게 할 수 있었다. 방전전력이 같은 경우 성장된 박막의 형태는 반응관 압력을 증가시킴에 따라 자형면을 가진 입자로부터 미립자 도는 구성의 입자로 변화되었다. $H_2와{\;}CH_4의$ 혼합가스로부터 Si기판 위에 다이아몬드 박막을 성장시키는 경우, CH4 농도가 0.5vol% 이하가 되어야만 양질의 다이아몬드 박막을 성장시킬 수 있었다. 성장된 다이아몬드 박막은 SEM, XRD 및 Raman 분광기를 사용하여 평가하였다.

• 한국세라믹학회지
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• 제45권12호
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• pp.796-801
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• 2008

$LaGaO_3$ thin film was prepared on Ni-Fe metal porous substrate by Pulsed Laser Deposition method. By the thermal reduction, the dense $NiO-{Fe_3}{O_4}$ substrate is changed to a porous Ni-Fe metal substrate. The volumetric shrinkage and porosity of the substrate are controlled by the reduction temperature. It was found that a thermal expansion property of the Ni-Fe porous metal substrate is almost the same with that of $LaGaO_3$ based oxide. $LaGaO_3$ based electrolyte films are prepared by the pulsed laser deposition (PLD) method. The film composition is sensitively affected by the deposition temperature. The obtained film is amorphous state after deposition. After post annealing at 1073K in air, the single phase of $LaGaO_3$ perovskite was obtained. Since the thermal expansion coefficient of the film is almost the same with that of LSGM film, the obtained metal support LSGM film cell shows the high tolerance against a thermal shock and after 6 min startup from room temperature, the cell shows the almost theoretical open circuit potential.

• 한국전기전자재료학회논문지
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• 제29권8호
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• pp.505-509
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• 2016

We have investigated the characteristics of amorphous silicon (a-Si) thin-film solar cell by inserting barrier layer. The conversion efficiency of a-Si thin-film solar cells on graphite substrate shows nearly zero because of the surface roughness of the graphite substrate. To enhance the performance of solar cells, the surface morphology of the back side were modified by changing the barrier layer on graphite. The surface roughness of graphite substrate with the barrier layer grown by plasma enhanced chemical vapor deposition (PECVD) reduced from ~2 um to ~75 nm. In this study, the combination of the barrier layer on graphite substrate is important to increase solar cell efficiency. We achieved ~ 7.8% cell efficiency for an a-Si thin-film solar cell on graphite substrate with SiNx/SiOx stack barrier layer.

• 한국표면공학회지
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• 제29권5호
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• pp.540-544
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• 1996

To apply the CVD diamond film to coated tools, it is necessary to make adhesion strength between diamond film and substrate stronger. So adhesion strength of diamond coated WC-Co tools using Microwave Plasma CVD and cutting test of Al-18mass%Si alloy using diamond cutting tools were studied. Diamond coating was carried out using Microwave Plasma CVD apparatus. Reaction gas was used mixture of methane and hydrogen. Substrate temperature were varied from 673K to 1173K by control of microwave output power and reaction pressure. By observation of SEM, grain size became larger and larger as substrate temperature became higher and higher. Also all deposits were covered with clear diamond crystals. XRD results, the deposits were identified to cubic diamond. An analysis using Raman spectroscopy, the deposit synthesized at lower substrate temperature (673K) showed higher quality than deposit synthesized at higher substrate temperature (1173K). As a result of scratch adhesion strength test, from 873K to 1173K adhesion strength decreased by rising of substrate temperature. The deposit synthesized at 873K showed best adhesion strength. In the cutting test of Al-18mass%Si alloy using diamond coated tools and the surface machinability of Al-Si works turned with diamond coating tools which synthesized at 873K presented uniform roughness. Cutting performance of Al-18mass%Si alloys using diamond coated WC-Co tools related to the adhesion strength.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1995년도 추계학술대회 논문집 학회본부
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• pp.472-474
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• 1995

A Sputter ion Plating(SIP) system with a r.f. coil electrode and the Facing Target Sputter(FTS) source was designed for high-quality thin film formation. The rf discharge was combined with DC facing target sputtering in order to enhance ionization degree of a sputtered atoms. The energy of ions incident on the substrate depended on the health potential of DC biased substrate. The mean impact ion energy increased with negative bias voltage and rf power. The adhesive force of the TiN film formed was in the range of 30$\sim$50N, and markedly influenced by substrate bias voltage.

• 한국표면공학회지
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• 제40권5호
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• pp.209-213
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• 2007

Change of the plasma volume by pulse frequency in a bipolar pulsed DC unbalanced magnetron sputtering was investigated. As increasing the frequency at off duty 10% and at a constant power, the plasma volume was lengthened in vertical direction from the AZO target. When there is an electrically floated substrate, the vertical length of the plasma area was not affected by the pulse frequency. Instead, the diameter of the plasma volume was increased. We found that the temperature rise of a substrate was affected by the pulse frequency, too. As increasing it, the maximum temperature rise of a glass substrate was decreased from $132^{\circ}C\;to\;108^{\circ}C$.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 추계학술대회 논문집 학회본부
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• pp.206-208
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• 1996

Thin films of magnesium oxide(MgO) were deposited on glass substrates by RF magnetron sputtering method. The characteristics of MgO thin films were analyzed as a function of various deposition conditions such as substrate temperature, substrate self-bias, input power and pressure. As the substrate temperature and bias voltage were increased, the grain size of MgO thin film increased. XRD peaks of (111) and (222) direction became dominant, as the substrate bias voltage increases and temperature decreases.

• 한국안광학회지
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• 제9권2호
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• pp.291-299
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• 2004

ECR-PECVD 방법을 이용하여 ECR power, $CH_4/H_2$ 가스 혼합비와 유량, 증착시간을 고정 시켜놓고 기판 bias 전압을 변화 시켜가면서 유리 기판위에 DLC 박막을 제작하였다. Raman, FTIR 및 UV/Vis 스펙트럼을 측정하여 기판 bias 진압에 따른 이용 충돌이 박막의 특성 변화에 미치는 영향을 조사하였다. FTIR 분석결과로부터 기판 bias 전압을 증가시킬수록 이용충돌 현상이 두드러져 탄소와 결합하고 있던 수소원자들의 탈수소화 현상을 확인할 수 있었고, 박막의 두께는 bias 전압을 증가시킬수록 감소되었다. 그리고 Raman 스펙트럼으로부터 Gaussian curve fitting을 통하여 sp3/sp2의 결합수에 비례하는 D/G피크의 면적 강도비(ID/IG)는 기판 bias 전압을 증가시킬수록 증가하였다. 그리고 광 투과율은 증착시간을 길게 할수록, 기판 bias 전압을 크게할수록 감소하였으나, 박막의 밀도가 증가하고 더 매끄러운 DLC 박막이 형성되었다. 이 결과로부터 DLC 박막은 기판 bias 전압의 크기를 증가시킬수록 특성이 더 향상됨을 알 수 있었다.