• 전기전자학회논문지
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• 제23권3호
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• pp.756-761
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• 2019

본 논문에서는 기존 4H-SiC SJ UMOSFET 구조의 p-pillar을 기존 UMOSFET의 shielding 영역 아래로 배치시키는 SC-SJ(Shielding Connected-Super Junction) UMOSFET 구조를 제안한다. 제안한 SC-SJ UMOSFET의 경우 p-pillar와 shielding 영역이 공존하여 산화막에서 전계에 의한 항복이 발생하지 않도록 하며, 이는 pillar의 도핑 농도 상승을 가능하게 한다. 결과적으로 온저항을 낮춤으로서 소자의 정적 특성을 개선한다. Sentaurus TCAD 시뮬레이션을 통해 기존 구조와 제안한 구조의 정적 특성을 비교, 분석하였다. 제안한 SC-SJ UMOSFET은 기존 구조에 비해 항복전압의 변화 없이 50% 감소된 온저항을 얻을 수 있다.

• Current Photovoltaic Research
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• 제7권3호
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• pp.76-84
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• 2019

Silicon heterojunction solar cells (SHJ) have dominated the photovoltaic market up till now but their conversion performance is practically limited to around 26% compared with the theoretical efficiency limit of 29.4%. A silicon based multi-junction devices are expected to overcome this limitation. In this report, we briefly review the state-of-art characteristic of wide-gap materials which has played a role as top sub-cells in silicon based multi-junction solar cells. In addition, we indicate significantly practical challenges and key issues of these multi-junction combination. Finally, we focus to some characteristics of III-V/c-Si tandem configuration which are reaching highly record performance in multi-junction silicon solar cells.

• 대한전자공학회논문지SD
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• 제39권10호
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• pp.25-34
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• 2002

본 논문에서는 코발트 실리사이드가 형성된 얕은 p+-n과 n+-p 접합의 전류-전압 특성을 분석하여 silicidation에 의해 형성된 Schottky contact 면적을 구하였다. 역방향 바이어스 영역에서는 Poole-Frenkel barrier lowering 효과가 지배적으로 나타나서 Schottky contact 효과를 파악하기가 어려웠다. 그러나 Schottky contact의 형성은 순방향 바이어스 영역에서 n+-p 접합의 전류-전압 (I-V) 동작에 영향을 미치는 것으로 확인되었다. 실리사이드가 형성된 n+-p 다이오드의 누설전류 증가는 실리사이드가 형성될 때 p-substrate또는 depletion area로 코발트가 침투퇴어 Schottky contact을 형성하거나 trap들을 발생시켰기 때문이다. 분석결과 perimeter intensive diode인 경우에는 silicide가 junction area까지 침투하였으며, area intensive junction인 경우에는 silicide가 비록 공핍층이나 p-substrate까지 침투하지는 않았더라도 공핍층 근처까지 침투하여 trap들을 발생시켜 누설전류를 증가시킴을 확인하였다. 반면 p+-n 다이오드의 경우 Schottky contact이발생하지 않았고 따라서 누설전류도 증가하지 않았다. n+-p 다이오드에서 실리사이드에 의해 형성된 Schottky contact 면적은 순방향 바이어스와 역방향 바이어스의 전류 전압특성을 동시에 제시하여 유도할 수 있었고 전체 접합면적의 0.01%보다 작게 분석되었다.

• Progress in Superconductivity
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• 제10권2호
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• pp.144-148
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• 2009

A current limiter was manufactured using a Josephson junction array to cut off an excessive current flowing into the SQUID sensor. The Fabricateed Josephson junction array was connected in series with a flux transformer that consists of a pick-up coil and an input coil, and the flux transformer was inductively coupled with a Double Relaxation Oscillation SQUID(DROS). The flux-voltage modulation curve was induced by applying an AC magnetic field whose magnitude was far smaller than that of the DC magnetic field. A change in the flux-voltage modulation curve of the SQUID was observed while the DC magnetic field was increased, to qualitatively examine the current limiting characteristic of the Josephson junction array. As a result, it was found that the SQUID flux-voltage modulation curve disappeared at the critical current of the Josephson junction array, which indicates that the Josephson junction array properly works as a current limiter.

• 전자공학회논문지D
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• 제35D권5호
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• pp.87-92
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• 1998

Ultr shallow p$^{+}$-n junction with Co/Ti bilayer silicidde contact was formed by ion implantation of BF$_{2}$ [energy : (30, 50)keV, dose:($5{\times}10^{14}$, $5{\times}10^{15}$/$\textrm{cm}^2$] onto the n-well Si(100) region and by RTA-silicidation and post annealing of the evaporated Co(120.angs., 170.angs.)/Ti(40~50.angs.) double layer. The sheet resistance of the silicided p$^{+}$ region of the p$^{+}$-n junction formed by BF2 implantation with energy of 30keV and dose of $5{\times}10^{15}$/$\textrm{cm}^2$ and Co/Ti thickness of $120{\AA}$/(40~$50{\AA}$) was about $8{\Omega}$/${\box}$. The junction depth including silicide thickness of about $500{\AA}$ was 0.14${\mu}$. The fabricated p$^{+}$ -n ultra shallow junction depth including silicide thickness of about $500{\AA}$ was 0.14${\mu}$. The fabricated p$^{+}$-n ultra shallow junction with Co/Ti bilayer silicide contact did not show any agglomeration or variation of sheet resistance value after post annealing at $850^{\circ}C$ for 30 minutes. The boron concentration at the epitaxial CoSi$_{2}$/Si interface of the fabricated junction was about 6*10$6{\times}10^{19}$ / $\textrm{cm}^2$./TEX>.

• 전자공학회논문지A
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• 제31A권12호
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• pp.80-90
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• 1994

To develop VLSI of higher packing density with 0.5.mu.m gate length of less, semiconductor devices require shallow junction with higher doping concentration. the most common method to form the shallow junction is ion implantation, but in order to remove the implantation induced defect and activate the implanted impurities electrically, ion-implanted Si should be annealed at high temperature. In this annealing, impurities are diffused out and redistributed, creating deep PN junction. These make it more difficult to form the shallow junction. Accordingly, to miimize impurity redistribution, the thermal-budget should be kept minimum, that is. RTA needs to be used. This paper reports results of the diffusion characteristics of PSG film by varying Phosphorus weitht %/ Times and temperatures of RTA. From the SIMS.ASR.4-point probe analysis, it was found that low sheet resistance below 100 .OMEGA./ㅁand shallow junction depths below 0.2.mu.m can be obtained and the surface concentrations are measured by SIMS analysis was shown to range from 2.5*10$^{17}$ aroms/cm$^{3}$~3*10$^{20}$ aroms/cm$^{3}$. By depending on the RTA process of PSG film on Si, LDD-structured nMOSFET was fabricated. The junction depths andthe concentration of n-region were about 0.06.mu.m. 2.5*10$^{17}$ atom/cm$^{-3}$ , 4*10$^{17}$ atoms/cm$^{-3}$ and 8*10$^{17}$ atoms/cm$^{3}$, respectively. As for the electrical characteristics of nMOS with phosphorus junction for n- region formed by RTA, it was found that the characteristics of device were improved. It was shown that the results were mainly due to the reduction of electric field which decreases hot carriers.

• 동의생리병리학회지
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• 제32권2호
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• pp.106-112
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• 2018

The aim of this research was to determine the diverse effects of Sappan Lignum extract and brazilin on human keratinocyte HaCaT cells. We confirmed the antioxidant effect of Sappan Lignum extract and brazilin was analyzed by using an ABTS assay, confirming the efficacy of water extraction method. Also, we examined effect of Sappan Lignum extract and brazilin on the cell viability, using the MTS assay in HaCaT cells. mRNA expression levels of tight junction-related genes associated with skin barrier in HaCaT cells were analyzed using quantitative real-time PCR analysis. Sappan Lignum extract increased the cellular activity of HaCaT cells and the expression of the tight junction-related genes claudin 3, claudin 6, and ZO-2. Brazilin displayed the same effects as that of the extract on HaCaT cells activity and tight junction-related genes expression. Furthermore, dispase assay demonstrated altered cell-cell adhesion strength of Sappan Lignum extract or brazilin treated HaCaT cells. Sappan Lignum extract or brazilin might be an useful ingredient in skin-mosturizinng and anti-wrinkle cosmetics, given its effects of altering mRNA expression of tight junction-related genes and enhancing cell-cell adhesion strength of HaCaT cells.

• The Korean Journal of Physiology and Pharmacology
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• 제11권3호
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• pp.107-112
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• 2007

Gap junction protein, connexin, is expressed in endothelial cells of vessels, glomerulus, and renin secreting cells of the kidney. The purpose of this study was to investigate the role of gap junction in renin secretion and its underlying mechanisms using As 4.1 cell line, a renin-expressing clonal cell line. Renin release was increased proportionately to incubation time. The specific gap junction inhibitor, 18-beta glycyrrhetinic acid (GA) increased renin release in dose-dependent and time-dependent manners. Heptanol and octanol, gap junction blockers, also increased renin release, which were less potent than GA. GA-stimulated renin release was attenuated by pretreatment of the cells with amiloride, nifedipine, ryanodine, and thapsigargin. GA dose-dependently increased intracellular $Ca^{2+}$ concentration, which was attenuated by nifedipine, nimodipine, ryanodine, and thapsigargin. However, RP-cAMP, chelerythrine, tyrphostin A23, or phenylarsine oxide did not induced any significant change in GA-stimulated increase of intracellular $Ca^{2+}$ concentration. These results suggest that gap junction plays an important role on the regulation of renin release and intracellular $Ca^{2+}$ concentration in As 4.1 cells.

• 한국방재학회 논문집
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• 제6권4호통권23호
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• pp.57-65
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• 2006

본 연구에서는 본류와 지류가 만나는 합류구간, 만곡 및 사행구간이 있는 자연하천과 동일한수리모형을 제작하고 합류부를 중심으로 본류와 지류의 유량비 변화에 따라 모형의 합류부 횡단면에서 발생하는 수위차의 변화를 분석하였다. 합류이전의 최하류단면 수위를 기준으로 하는 합류부 각 단면의 최대수위 변화에 미치는 유량비의 영향은 합류부 하류구간보다 상류구간에서 더 크게 나타난다. 횡단면의 최소수위에 대한 최대수위의 변화는 합류부 중심에 가까울수록 증가하며 합류부 중심 직하류에서 최대를 보인다. 또한 합류구간 횡단면의 수면경사는 단면형태에 따라 영향을 받으며 본류에 대한 지류의 유량비가 감소할수록 수면경사도 감소한다. 기존에 제안된 일정한 곡률반경과 정형화된 단면에서 도출된 횡단면 수위차 산정 공식이 평창강과 동일하게 제작된 모형수로에서 실측값과 약 60%의 차이를 보인 반면 본 연구에서는 실측값과 약 10%의 차이를 보이는 수위차 산정 공식을 제안하였다.

• 한국정보기술학회논문지
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• 제16권11호
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• pp.77-84
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• 2018

본 논문에서는 T-junction 전력 분배기를 이용한 원형 편파 마이크로스트립 패치 안테나를 제안하였다. 제안된 안테나의 동작 주파수는 2.4GHz의 ISM 대역이며, 패치 안테나의 두 가장자리에 $90^{\circ}$의 위상차를 급전하여 원형 편파를 유도하였다. 안테나의 구조는 일반적인 패치 안테나와 T-junction 전력 분배기로 구성된다. 안테나의 최적화를 위해 반사계수, 축비, 방사패턴 등이 분석된다. 안테나의 임피던스 대역폭은 2.39~2.43GHz 대역에서 40MHz의 대역폭이 관찰되었으며, 축비 대역폭은 2.398~2.410GHz 대역에서 약 12MHz의 대역폭이 관찰되었다. 안테나의 방사패턴은 우회전 원형 편파로 동작하였다. 또한 안테나의 이득은 XZ 및 YZ-평면에서 각각 2.04, 3.4㏈ic가 관찰되었다.