• 전자공학회논문지A
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• 제33A권7호
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• pp.134-142
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• 1996

The epi-CoSi$_{2}$ layer was formed by alloying a Co(120$\AA$)/Ti(50$\AA$) bilayer. In addition, the ultra shallow p$^{+}$n junction of which depth is about not more than 40nm at the background concentration, 10$^{18}$atoms/cm$^{3}$ could be formed by annealing (RTA-II) the ion implanted epi-silicide. When the temperature of RTA-I is as low as possible and that of RTA-II is moderate, the p$^{+}$n junction that has low leakage current and stable epi-silicide layer could be obtained. That is, when th econdition of TRA-I was 900$^{\circ}C$/20sec and that of RTA-II was 900$^{\circ}C$/10sec, the reverse leakage current was as high as 11.3$\mu$A/cm$^{2}$ at -5V. The surface of CoSi$_{2}$ appeared considerably rough. However, when the conditon of RTA-I was 800$^{\circ}C$/20sec or 700$^{\circ}C$/20sec, the leakage currents were as low as 8.3nA/cm$^{2}$ and 9.3nA/cm$^{2}$, respectively and also the surfaces appeared very uniform.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2010년도 하계학술대회 논문집
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• pp.350-350
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• 2010

Silicon carbide (SiC), one of the well known wide band gap semiconductors, shows high thermal conductivities, chemical inertness and breakdown energies. The design of normally-off 4H-SiC VJFETs [1] has been reported and 4H-SiC VJFETs with different lateral JFET channel opening dimensions have been studied [2]. In this work, 4H-SiC based VJFETs has been designed using the device simulator (ATLAS, Silvaco Data System, Inc). We varied the n-epi layer thickness (from $6\;{\mu}m$ to $10\;{\mu}m$) and the channel width (from $0.9\;{\mu}m$ to $1.2\;{\mu}m$), and investigated the static characteristics as blocking voltages, threshold voltages, on-resistances. We have shown that silicon carbide JFET structures of highly intensified blocking voltages with optimized figures of merit can thus be achieved by adjusting the epi layer thickness and channel width.

• JSTS:Journal of Semiconductor Technology and Science
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• 제14권3호
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• pp.274-283
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• 2014

In this paper, the epi layer of npn SOI HBT with n+ buried layer has been studied through Sentaurus process and device simulator. The doping value of the deposited epi layer has been varied for the npn HBT to achieve improved $f_tBV_{CEO}$ product (397 GHzV). As the $BV_{CEO}$ value is higher for low value of epi layer doping, higher supply voltage can be used to increase the $f_t$ value of the HBT. At 1.8 V $V_{CE}$, the $f_tBV_{CEO}$ product of HBT is 465.5 GHzV. Further, the film thickness of the epi layer of the SOI HBT has been scaled for better performance (426.8 GHzV $f_tBV_{CEO}$ product at 1.2 V $V_{CE}$). The addition of this HBT module to fully depleted SOI CMOS technology would provide better solution for realizing wireless circuits and systems for 60 GHz short range communication and 77 GHz automotive radar applications. This SOI HBT together with SOI CMOS has potential for future high performance SOI BiCMOS technology.

• Biotechnology and Bioprocess Engineering:BBE
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• 제6권1호
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• pp.51-55
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• 2001

This study was conducted to establish a plant cell culture system for the production of medically important secondary metabolites from Xanthium strumarium. The effects of plant growth regulators including NAA, 2,4-D, kinetin, and ABA were examined in terms of callus induction, maintenance of callus and suspension cultures. It was shown that callus was induced upon treatment with NAA while embryo was induced after treatment with 2,4-D. Callus formation was further improved by treatment with ABA and NAA. The level of callusing increased by 17-29% for the seed case, cotyledon, leaf, and hypocotyl and by 96% in the case of the root. Suspension cell lines were established using calli produced from cotyledon, hypocotyl and root and cultured at 25$\^{C}$ under light conditions. The cells grew up to 15g/L with NAA 2ppm, BA 2ppm, and ABA 1ppm treatment. Supernatants of suspension cultures of cell lines derived from coyledon and hypocotyl produced some distinctive secondary metabolites, one of which was identified as 8-epi-tomentosin, which belongs to the xanthanolides. The amounts of 8-epi-tomentosin produced by the cotyledon- and hypocotylderived cell lines were 13.4mg/L and 11.0mg/L, respectively.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2001년도 춘계종합학술대회
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• pp.311-316
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• 2001

소자의 고집적을 위한 특성분석 기술은 빠른 변화를 보이고 있다. 이에 따라 고집적 소자의 특성을 시뮬레이션을 통하여 이해하고 이에 맞게 제작하는 기술을 매우 중요한 과제 중의 하나가 되었다. 소자가 마이크론급에서 나노급 이하로 작아지면서 그에 맞는 소자개발을 위해 여러 가지 구조가 제시되고 있는데 본 논문에서는 TCAD를 이용하여 여러 가지 구조 중에서 고농도로 도핑된 ground plane 위에 적층하여 만든 EFI MOSFET와 LDD구조의 단점을 개선한 newEPI MOSFET에 대해 조사하였다. 이 구조의 특성과 임팩트이온화와 전계 그리고 I-V 특성 곡선을 저 농도로 도핑된 드레인(LDD) MOSFET와 비교 분석하였다. 또한 TCAD의 유용성을 조사하여 시뮬레이터로서 적합함과 나노구조 소자에서의 스켈링이론의 적합함을 보았다.

• 센서학회지
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• 제27권1호
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• pp.40-46
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• 2018

In this paper, we focus on optimization of a boron ($^{11}B$)-implanted n type Si epi substrate for obtaining near-zero temperature coefficient of resistance (TCR) at temperature range from 25 to $125^{\circ}C$. The $^{11}B$-implantation on the N type-Si epi substrate formed isolation from the rest of the N-type Si by the depletion region of a PN junction. The TCR increased as the temperature of rapid thermal anneal (RTA) was increased at the temperature range from $900^{\circ}C$ to $1000^{\circ}C$ for the $p^+$ contact with implantation at dose of $1E16/cm^2$, but sheet resistance of this film was decreased. After the optimization of anneal process condition, the TCR of $1126.7{\pm}30.3$ (ppm/K) was obtained for the $p^-$ resistor-COB package chips contained $p^+$ contact with the implantation of $5E14/cm^2$. This shows the potential of the $^{11}B$-implanted n type Si epi substrate as a resistor for pressure sensor in thermal stable environment applications..

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 하계학술대회 논문집 Vol.5 No.1
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• pp.288-291
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• 2004

Due to the charge compensation effect, SOI(Silicon-On-Insulator) LIGBT with dual-epi layer have been found to exhibit both low forward voltage drop and high static breakdown voltage. In this paper, electrical characteristics of the SOI LIGBT with dual-epi structure is presented. Trenched anode structure is employed to obtain uniform current flowlines and shorted anode structure also employed to prevent the fast latch-up. Latching current density of the proposed LIGBT with $T_1=T_2=2.5{\mu}m,\;N_1=7{\times}10^{15}/cm^3,\;N_2=3{\times}10^{15}/cm^3$ is $800A/cm^2$ and breakdown voltage is 125V while latching current density and breakdown voltage of the conventional LIGBT is $700A/cm^2$ and 55V.

• 식물조직배양학회지
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• 제25권3호
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• pp.141-146
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• 1998

[$^3$H] 5-epi-aristolochene (5-EAS)를 담배 현탁배양세포에 투여하여 elicitor에 의해 유도된 세포가 생합성하여 배지로 방출하는 [$^3$H]-capsidiol의 량을 측정함으로써 5-EAS hydroxylase의 활성을 검정하였고, 이 반응의 전 단계에 관여하는 효소인 sesquiterpene cyclase의 발현특성과 비교하였다. 5-EAS hydroxylase는 정상세포에는 전혀 활성을 보이지 않으나 elicitor로써 cellulase를 처리한 세포는 9시간 후부터 유도를 시작하여 18시간 후에 최대 활성을 보였는데 동일한 세포내에서 유도되는 cyclase와 유사한 패턴을 보였다. Cyt P450계 효소의 특이적 억제제로 알려진 ancymidol과 ketoconazole에 의해 5-EAS hydroxylase의 활성은 강한 억제를 보인 반면 cyclase의 활성은 억제를 보이지 않아 5-EAS hydroxylase가 P450계 효소임이 시사되었다.

• 한국광학회지
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• 제22권3호
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• pp.141-150
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• 2011

현재까지 더 좋은 성능의 LED 램프 패키지 구조의 개발을 위해 많은 연구가 진행되어 왔음에도 불구하고 아직 LED 램프 패키지 설계에 관한 표준화된 이론이나 지침 같은 것들이 마련되지 못한 것으로 판단된다. 이에 본 논문에서는 먼저 Monte Carlo photon simulation 기법을 이용하여 InGaN/Sapphire LED의 칩 구조 및 Epi-up 혹은 Epi-down 칩 부착 방식을 광추출효율 관점에서 분석하였다. 그리고 분석결과를 바탕으로 LED 램프 패키지 설계에 관한 기본 지침을 마련하였다. 이와 같이 마련된 설계지침은 관련 기업이나 연구기관에서, LED 램프의 구체적 응용분야에 따라 최적화된 패키지 구조를 설계하는 데에 중요하게 활용될 수 있을 것으로 기대된다.

• Biomolecules & Therapeutics
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• 제29권3호
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• pp.290-294
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• 2021

Extracellular beta amyloid (Aβ) plaques are the neuropathological hallmarks of Alzheimer's disease (AD). Accordingly, reducing Aβ levels is considered a promising strategy for AD prevention. 3'-O-acetyl-24-epi-7,8-didehydrocimigenol-3-O-β-D-xylopryranoside significantly decreased the Aβ production and this effect was accompanied with reduced sAPPβ production known as a soluble ectodomain APP fragment through β-secretases in HeLa cells overexpressing amyloid precursor proteins (APPs). This compound also increased the level of sAPPα, which is a proteolytic fragment of APP by α-secretases. In addition, 3'-O-acetyl-24-epi-7,8-didehydrocimigenol-3-O-β-D-xylopryranoside decreased the protein level of β-secretases, but the protein levels of A disintegrin and metalloproteinase (ADAM) family, especially ADAM10 and ADAM17, are increased. Thus, 3'-O-acetyl-24-epi-7,8-didehydrocimigenol-3-O-β-D-xylopryranoside could be useful in the development of AD treatment in the aspect of amyloid pathology.