• 한국진공학회:학술대회논문집
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• 한국진공학회 2009년도 제38회 동계학술대회 초록집
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• pp.151-151
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• 2010

In this paper, the electrically properties of nonvolatile memory (NVM) using multi-stacks gate insulators of oxide-nitride-oxynitride (ONOn) and active layer of the low temperature polycrystalline silicon (LTPS) were investigated. From hydrogenated amorphous silicon (a-Si:H), the LTPS thin films with high crystalline fraction of 96% and low surface's roughness of 1.28 nm were fabricated by the metal induced crystallization (MIC) with annealing conditions of $650^{\circ}C$ for 5 hours on glass substrates. The LTPS thin film transistor (TFT) or the NVM obtains a field effect mobility of ($\mu_{FE}$) $10\;cm^2/V{\cdot}s$, threshold voltage ($V_{TH}$) of -3.5V. The results demonstrated that the NVM has a memory window of 1.6 V with a programming and erasing (P/E) voltage of -14 V and 14 V in 1 ms. Moreover, retention properties of the memory was determined exceed 80% after 10 years. Therefore, the LTPS fabricated by the MIC became a potential material for NVM application which employed for the system integration of the panel display.

• 한국응용과학기술학회지
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• 제16권4호
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• pp.313-316
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• 1999

Organic semiconductors based on conjugated thiophene oligomer have great potential to be utilized as an active layer for electronic and optoelectronic devices. In this study, a conjugated oligomer such as ${\alpha}$-sexithiophene (${\alpha}$-6T) thin films was prepared by the Organic Molecular Beam Deposition (OMBD), and various electrode materials were also deposited by a simple vacuum evaporation, respectively. Those films were photolithographically patterned for the electrical measurements. Electrical charact-erization of the thin film transistor with various channel length were executed and the field effect mobility of these thin film transistors were also calculated by the formula using the experimental data.

• 반도체디스플레이기술학회지
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• 제16권4호
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• pp.59-62
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• 2017

In this paper, atmospheric pressure plasma treatment was proposed for high performance indium gallium zinc oxide thin film transistor (IGZO TFT). RF Ar plasma treatment is performed at room temperature under atmospheric pressure as a simple and cost effective channel surface treatment method. The experimental results show that field effect mobility can be enhanced by $2.51cm^2/V{\cdot}s$ from $1.69cm^2/V{\cdot}s$ to $4.20cm^2/V{\cdot}s$ compared with a conventional device without plasma treatment. From X-ray photoelectron spectroscopy (XPS) analysis, the increase of oxygen vacancies and decrease of metal-oxide bonding are observed, which suggests that the suggested atmospheric Ar plasma treatment is a cost-effective useful process method to control the IGZO TFT performance.

• 전자통신동향분석
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• 제37권5호
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• pp.11-21
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• 2022

GaN (Gallium-Nitride) is a promising candidate material in various radio frequency applications due to its inherent properties including wide bandgap, high carrier concentration, and high electron mobility/saturation velocity. Notably, AlGaN/GaN heterostructure field effect transistor exhibits high operating voltage and high power-density/power at high frequency. In next-generation radar systems, GaN power transistors and monolithic microwave integrated circuits (MMICs) are significant components of transmitting and receiving modules. In this paper, we introduce technological trends for C-/X-/Ku-band GaN MMICs including power amplifiers, low noise amplifiers and switch MMICs, focusing on the status of GaN MMIC fabrication technology and GaN foundry service. Additionally, we review the research for the localization of C-/X-/Ku-band GaN MMICs using in-house GaN transistor and MMIC fabrication technology. We also discuss the results of C-/X-/Ku-band GaN MMICs developed at Defense Materials and Components Convergence Research Department in ETRI.

• 전기전자학회논문지
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• 제22권1호
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• pp.1-5
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• 2018

Sol-gel 공법을 이용하여, p-형 CuO 박막 트랜지스터를 제작하였다. 제작된 CuO 박막 트랜지스터는 copper (II) acetate monohydrate 를 전구체로 사용하였다. $500^{\circ}C$ 열처리 후에 형성된 전구체는 p-형 CuO 박막이 됨을 확인하였다. 또한 전구체를 형성하기 전 기판표면의 $UV/O_3$ 조사량에 따른 CuO 박막 트랜지스터의 전기적 특성변화에 대하여 연구하였으며, 600 초동안 $UV/O_3$를 조사한 경우 제작된 CuO 박막 트랜지스터는 $5{\times}10^{-3}\;cm^2/V{\cdot}s$ 의 이동도와 약 $10^2$의 온/오프 전류비를 보여주었다.

• 한국전기전자재료학회논문지
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• 제18권4호
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• pp.285-296
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• 2005

Reduced pressure chemical vapor deposition technology has been used to study SiGe heterostructure epitaxy and device issues, including SiGe relaxed buffers, proper control of Ge component and crystalline defects, two dimensional delta doping, and their influence on electrical properties of devices. From experiments, 2D profiles of B and P presented FWHM of 5 nm and 20 nm, respectively, and doses in 5×10/sup 11/ ∼ 3×10/sup 14/ ㎝/sup -2/ range. The results could be employed to fabricate SiGe/Si heterostructure field effect transistors with both Schottky contact and MOS structure for gate electrodes. I-V characteristics of 2D P-doped HFETs revealed normal behavior except the detrimental effect of crystalline defects created at SiGe/Si interfaces due to stress relaxation. On the contrary, sharp B-doping technology resulted in significant improvement in DC performance by 20-30 ％ in transconductance and short channel effect of SiGe HMOS. High peak concentration and mobility in 2D-doped SiGe heterostructures accompanied by remarkable improvements of electrical property illustrate feasible use for nano-sale FETs and integrated circuits for radio frequency wireless communication in particular.

• Transactions on Electrical and Electronic Materials
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• 제18권1호
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• pp.55-57
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• 2017

Amorphous oxide thin film transistors (TFTs) were fabricated with 0.5 wt% silicon doped zinc tin oxide (a-0.5SZTO) thin film deposited by radio frequency (RF) magnetron sputtering. In order to investigate the effect of annealing treatment on the electrical properties of TFTs, a-0.5SZTO thin films were annealed at three different temperatures ($300^{\circ}C$, $500^{\circ}C$, and $700^{\circ}C$ for 2 hours in a air atmosphere. The structural and electrical properties of a-0.5SZTO TFTs were measured using X-ray diffraction and a semiconductor analyzer. As annealing temperature increased from $300^{\circ}C$ to $500^{\circ}C$, no peak was observed. This provided crystalline properties indicating that the amorphous phase was observed up to $500^{\circ}C$. The electrical properties of a-0.5SZTO TFTs, such as the field effect mobility (${\mu}_{FE}$) of $24.31cm^2/Vs$, on current ($I_{ON}$) of $2.38{\times}10^{-4}A$, and subthreshold swing (S.S) of 0.59 V/decade improved with the thermal annealing treatment. This improvement was mainly due to the increased carrier concentration and decreased structural defects by rearranged atoms. However, when a-0.5SZTO TFTs were annealed at $700^{\circ}C$, a crystalline peak was observed. As a result, electrical properties degraded. ${\mu}_{FE}$ was $0.06cm^2/Vs$, $I_{ON}$ was $5.27{\times}10^{-7}A$, and S.S was 2.09 V/decade. This degradation of electrical properties was mainly due to increased interfacial and bulk trap densities of forming grain boundaries caused by the annealing treatment.

• 한국산학기술학회논문지
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• 제16권4호
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• pp.2556-2563
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• 2015

본 연구는 전문대학생이 경험하는 취업준비활동의 취업 효과를 밝히는 것이 목적이다. 특히 학생이 개인차원에서 준비하는 자격증, 직업훈련 등과 함께 대학 차원에서 운영하는 진로선택 및 취업지원 프로그램의 취업 효과를 분석하기 위해 수행되었다. 2011대졸자 직업이동경로조사 자료의 전문대졸자 3,249명을 대상으로 이항 로지스틱 회귀분석을 실시하였다. 분석 결과, 대학특성에서는 졸업학점이 높을수록, 출신대학이 비수도권일수록 취업 확률이 더 높았다. 전공계열은 준거집단 대비 의약, 교육, 공학, 사회, 자연 계열 순으로 취업 확률이 높았다. 취업준비활동에서는 국가 자격증 수가 많을수록, 면접기술 & 이력서작성 프로그램 참여 경험이 있는 경우, 졸업 전 후 구직활동 경험이 있는 경우가 취업에 영향을 미치는 것으로 나타났다. 그 외 직업훈련, 진로 취업관련 교과목, 직장체험 프로그램, 진로상담 프로그램, 취업캠프, 대학 재학 중 일자리 경험, 졸업 전 취업목표 유무 등은 취업에 직접적인 영향을 미치지는 못했다.

• 한국철도학회논문집
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• 제14권4호
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• pp.383-389
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• 2011

지금까지 고속철도와 고속도로의 계획 및 건설은 시설 간 연계 환승에 대한 고려 없이 개별시설 확충 위주로 진행되었으며. 이로 인해 시설의 효율적 투자 및 활용은 이루어지지 않았다. 본 연구에서는 고속도로 연계성 향상으로 고속철도 수단선택행태에 미치는 영향을 다항로짓모형(Multinominal Logit Model)과 이항로짓모형(Binary Logit Model)을 활용하여 분석하였다. 모형개발을 위한 설문조사는 고속철도, 고속버스, 장거리 승용차 이용자를 대상으로 통행실태조사와 진술선호조사를 수행하였으며, 이를 통해 고속철도와 연계 환승수단에 대한 수단분담모형을 구축하였다. 수단선택모형을 통하여 고속도로와 고속철도가 연계 시 동탄역을 대상으로 사례분석을 수행한 결과 서울~부산 간 약 2시간의 통행시간이 단축되었으며, 이로 인해 약 30%의 수요증가 효과가 있는 것으로 분석되었다. 본 연구를 통하여 고속철도와 고속도로의 계획 시 연계 환승을 고려하여 건설 및 운영이 이루어질 경우, 고속철도의 이동성 기능과 고속도로의 접근성 기능을 결합함으로써 수단간 효율성을 극대화할 수 있을 것으로 판단된다.

• 한국전기전자재료학회논문지
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• 제30권8호
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• pp.469-473
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• 2017

We investigated the effect of different thin-film thicknesses (25, 30, and 40 nm) on the electrical performance of solution-processed indium-zinc-oxide (IZO) thin-film transistors (TFTs). The structural properties of the IZO thin films were investigated by atomic force microscopy (AFM). AFM images revealed that the IZO thin films with thicknesses of 25 and 40 nm exhibit an uneven distribution of grains, which deforms the thin film and degrades the performance of the IZO TFT. Further, the IZO thin film with a thickness of 30 nm exhibits a homogeneous and smooth surface with a low RMS roughness of 1.88 nm. The IZO TFTs with the 30-nm-thick IZO film exhibit excellent results, with a field-effect mobility of $3.0({\pm}0.2)cm^2/Vs$, high Ion/Ioff ratio of $1.1{\times}10^7$, threshold voltage of $0.4({\pm}0.1)V$, and subthreshold swing of $0.7({\pm}0.01)V/dec$. The optimization of oxide semiconductor thickness through analysis of the surface morphologies can thus contribute to the development of oxide TFT manufacturing technology.