• 반도체디스플레이기술학회지
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• 제7권2호
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• pp.59-62
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• 2008

The Lifetime of OLEDs by ITO/glass substrates cleaning method and cathode deposition method were investigated in the fabrication of green light emitting OLEDs with $Alq_3$-C545T fluorescent system. In our experiments, the optimum cleaning method was obtained at last processing of boiling IPA(isopropyl alcohol). And the optimum deposition methode was obtained at 3 steps deposition rate of Al. The deposition rate of 3 steps progressed changing from $0.5\AA$/sec to $3\AA$/ sec. The green light emitting OLED with plasma treatment at 150W for 2 minutes showed the highest luminance and efficiency of 20000 cd/$m^2$ and 16 lm/W. On the contrary, the OLED device without plasma treatment showed much lower performance with the luminance and efficiency of 3500 cd/$m^2$ and 2 lm/W.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 하계학술대회 논문집 Vol.5 No.1
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• pp.181-184
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• 2004

Organic semiconductors have attracted considerable attention due to their interesting physical properties followed by various technological applications in the area of electronics and opto-electronics. It has been a long time since organic solar cells were expected as a low-cost high-energy conversion device. Although practical use of them has not been achieved, technological progress continues. Morphology of the materials, organic/inorganic interface, metal cathodes, molecular packing and structural properties of the donor and acceptor layers are essential for photovoltaic response. We have fabricated solar-cell devices based on copper-phthalocyanine(CuPc) as a donor(D) and fullerene($C_{60}$) as an electron acceptor(A) with doped charge transport layers, and BCP as an exciton blocking layer(EBL). We have measured photovoltaic characteristics of the solar-cell devices using the xenon lamp as a light source.

• 한국산업융합학회 논문집
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• 제22권2호
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• pp.219-226
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• 2019

This paper describes the development of a 500W DC/DC converter for use with a thermoelectric module(TEM). A thermoelectric device is a structure in which a P-type semiconductor and an N-type semiconductor are electrically connected in series and thermally connected in parallel. There is a feature that an electromotive force is generated by making a temperature difference between both surfaces of a thermoelectric element. This feature can be used as a renewable power source without the need for fossil energy. The proposed converter boosts the low generation voltage of the thermoelectric element to secure the voltage for the grid connection. This converter is a combination of a resonant converter for boosting and a boost-converter for output voltage control. This structure has an advantage that a voltage can be stepped up at a high efficiency and precise output voltage control is possible. We carry out simulations and experiments to verify the validity.

• 대한전자공학회논문지SD
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• 제39권1호
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• pp.83-88
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• 2002

HFET 소자의 선형성과 게이트-트레인 항복특성을 향상시키기 위해 부분채널 도핑된 Al/sub 0.25/Ga/sub 0.75/As/In/sub 0.25/Ga/sub 0.75/As/Al/sub 0.25/Ga/sub 0.75/As 이종접합 구조를 갖는 FET를 제안하였다. 제안된 HFET는 게이트 전극 아래로 도핑되지 않은 AlGaAs 진성공급층을 두어 -2OV 의 높은 항복전압을 얻었다. 또한 소자의 InGaAs 채널에 부분 도핑을 실시하여, 균일 채널 도핑을 실시한 경우보다 향상된 선형성을 유도하였고, 2차원 전산모사 견과와 제작 및 측정결과를 통해 선형성의 향상을 확인하였다. 본 실험에서 제안된 HFET소자는 DC측정 결과와 고주파측정 결과 모두에서 기존의 FET소자들에 비해 향상된 선형성을 나타내었다.

• 조명전기설비학회논문지
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• 제13권4호
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• pp.87-95
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• 1999

새로운 종류의 고체상태 대전력, 고속전자장치 즉 광전도전력스위치(PCPS)의 가장 큰 문제점은 평균전계하의 표면에서 스위치 섬락의 대부분이 반도체의 벌크파괴보다 낮다는 것이다. 이러한 문제를 극복하고 고밀도 고체 전력 스위치에 사용할 수 있는 유일한 방법이 고체 절연물로 표면을 페시베이션(Passivation)하는 것이다. 본 실험에서 Silicon의 절연내력은 진공중에서 10[kV/cm]에서 심하게 열화되어졌고, 기중에서 30[kV/cm], SF6에서 80∼90[kV/cm]으로 개선되지만, 스위치의 주 응용이 진공 또는 우주에서 사용되기 때문에 이러한 현상은 매우 심각한 문제이다. 페시베이션후 소자들은 진공과 기중에서 언페시베이션된 소자가 SF6내에서 얻을 수 있는 만큼의 높은 파괴값을 가졌다. 이러한 결과로 볼 때 페시베이션된 소자들이 매우 우수한 파괴값을 가진다는 것을 알 수 있다. 본 논문은 고전계 하에서 페시베이션 전·후 실리콘 파괴의 주 특성과 메커니즘에 대해 밝혔다.

• 마이크로전자및패키징학회지
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• 제9권4호
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• pp.11-16
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• 2002

본 연구에서는 $SrBi_2Ta_2O_9$ (SBT)박막의 고속식각에 따른 잔류물질 및 식각 손상의 영향을 조사하였다. ICP-RIE (inductively coupled plasma reactive ion etching) 의 ICP power와 CCP(capacitively coupled plasma) power를 변화시키면서 고속식각에 따른 박막의 손상과 열화를 XPS 분석과 Capacitance-Voltage (C-V) 측정을 통하여 알아보았다. ICP와 CCP의 power가 증가함에 따라 식각율이 증가하였고 ICP power가 700 W, CCP power가 200 W 일때 식각율은 900$\AA$/min이었다. 강유전체의 건식식각에 있어서 문제점이 플라즈마에 의한 강유전체 박막의 열화인데 반응가스 $Ar/C1_2/CHF_3$를 20/14/2의 비율로 사용하고 ICP와 CCP power를 각각 700w와 200w로 사용하였을 때 전혀 열화되지 않는 강유전체 박막의 특성을 얻을 수 있었다. 본 연구 결과는 Metal-Ferroelectric-Semiconductor (MFS) 또는 Metal-Ferroelectric-Insulator-Semiconductor (MFIS) 구조를 가지는 단일 트랜지스터형 강유전체 메모리 소자를 만드는데 건식 식각이 응용될 수 있음을 보여준다

• 한국전기전자재료학회논문지
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• 제30권8호
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• pp.525-529
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• 2017

Molybdenum oxide ($MoO_3$) offers pivotal advantages for high optical transparency and low light reflection. Considering device fabrication, n-type $MoO_3$ semiconductor can spontaneously establish a junction with p-type Si. Since the energy bandgap of Si is 1.12 eV, a maximum photon wavelength of around 1,100 nm is required to initiate effective photoelectric reaction. However, the utilization of infrared photons is very limited for Si photonics. Hence, to enhance the Si photoelectric devices, we applied the wide energy bandgap $MoO_3$ (3.7 eV) top-layer onto Si. Using a large-scale production method, a wafer-scale $MoO_3$ device was fabricated with a highly crystalline structure. The $MoO_3/p-Si$ heterojunction device provides distinct photoresponses for long wavelength photons at 900 nm and 1,100 nm with extremely fast response times: rise time of 65.69 ms and fall time of 71.82 ms. We demonstrate the high-performing $MoO_3/p-Si$ infrared photodetector and provide a design scheme for the extension of Si for the utilization of long-wavelength light.

• 한국기계가공학회지
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• 제13권5호
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• pp.28-34
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• 2014

A planetary gear train is more compact and endures greater amounts of transmission power compared to other gear systems. Although planetary gear systems operate in small volumes, they are capable of very high efficiency due to the compact combination of their gears in the planetary gear system. They also have outstanding efficiency of only 3% for power transmission, tantamount to the power loss that occurs in each of the shift stages. Given these advantages, planetary gear systems are used in the driving systems of, which are widely used in automobile transmissions, machine tools, semiconductor equipment, and in other areas in industrial fields. Current structural equipment requires higher efficiency and greater torque levels. According to these needs, we have designed a complex planetary gear system which creates higher levels of torque. In this paper, an evaluation of strength designs for the proposed planetary gear system was conducted to ensure the stability of the gear. In addition, a durability analysis based on Miner's rule was performed using RS B 0095 device.

• 전기학회논문지
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• 제62권11호
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• pp.1640-1646
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• 2013

Conventional power conversion unit that is a major part of the propulsion system has applied GTO thyristor as a switching semiconductor device of main circuit since introduction of the 8200 electric locomotive. But problem that quick maintenance is difficult and its cost is increasing occurs because major components of the power conversion unit are slowly discontinued. To solve these, in this paper, it was analyzed the response characteristic of the propulsion system modeling of the 8200 electric locomotive using IGBT which is applied recently to ensure propulsion control technology. As results of response for a Propulsion system modeling, it show that a power conversion unit is controlled by PLL(Phase-locked loop) and SVPWM(Space Voltage PWM) respectively.

• Transactions on Electrical and Electronic Materials
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• 제17권5호
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• pp.302-305
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• 2016

In this paper, a low on-resistance and high current driving capability trench gate power metal-oxide-semiconductor field-effect transistor (MOSFET) incorporating a current sensing feature is proposed and evaluated. In order to realize higher cell density, higher current driving capability, cost-effective production, and higher reliability, self-aligned trench etching and hydrogen annealing techniques are developed. While maintaining low threshold voltage and simultaneously improving gate oxide integrity, the double-layer gate oxide technology was adapted. The trench gate power MOSFET was designed with a 0.6 μm trench width and 3.0 μm cell pitch. The evaluated on-resistance and breakdown voltage of the device were less than 24 mΩ and 105 V, respectively. The measured sensing ratio was approximately 70:1. Sensing ratio variations depending on the gate applied voltage of 4 V ~ 10 V were less than 5.6%.