• 한국신뢰성학회지:신뢰성응용연구
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• 제16권1호
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• pp.1-6
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• 2016

Purpose: Fluorine doped tin oxide (FTO) bottom electrode for $Ta_2O_5$ based RRAM was studied to apply for transparent resistive switching memory devices owing to its superior transparency, good conductivity and chemical stability. Methods: $ITO/Ta_2O_5/FTO$ (ITF) and $ITO/Ta_2O_5/Pt$ (ITP) devices were fabricated on glass and Si substrate, respectively. UV-visible (UV-VIS) spectroscopy was used to examine transparency of the ITF device and its band gap energy was determined by conventional Tauc plot. Electrical properties, such as electroforming and voltage-induced RS characteristics were measured and compared. Results: The device with an FTO bottom electrode showed good transparency (>80%), low forming voltage (~-2.5V), and reliable bipolar RS behavior. Whereas, the one with Pt electrode showed both bipolar and unipolar RS behaviors unstably with large forming voltage (~-6.5V). Conclusion: Transparent and conducting FTO can successfully realize a transparent RRAM device. It is concluded that FTO electrode may form a stable interface with $Ta_2O_5$ switching layer and plays as oxygen ion reservoir to supply oxygen vacancies, which eventually facilitates a stable operation of RRAM device.

• 한국전자통신학회논문지
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• 제8권9호
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• pp.1307-1312
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• 2013

본 논문에서는 알칼리성 또는 산성을 띠는 특정 용액 내에서 전기분해 원리를 이용하여 금속 표면을 산화시켜 절연피막을 형성하는 장치를 개발한다. 기존에는 주로 양극에만 펄스 형태로 전압을 인가하는 단극성(unipolar) 방식이지만 본 논문에서는 H-브리지를 이용하여 양극에 양(+)전압과 음(-)전압을 번갈아 가면서 전압을 공급하는 양극성(bipolar) 장치를 제작하였으며, 금속 시편의 특성에 맞는 다양한 전기적인 조건을 가지고 산화피막을 형성할 수 있는 장치를 개발하였다. 공급전류 가변은 PWM 변조를 이용하였으며, (+)와 (-)의 극성변화는 H-브리지를 이용하여 양극성 펄스전압을 공급할 수 있도록 하였다. 그 결과로써 단극성보다 균일한 기공을 갖는 피막이 형성되었다.

• 한국마린엔지니어링학회:학술대회논문집
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• 한국마린엔지니어링학회 2005년도 전기학술대회논문집
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• pp.310-313
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• 2005

In this paper, four quadrant CBPS(Compact Bipolar Power Supply) which development and study using universal PWM controller. The CBPS has 24V DC-link voltage, +/-5A output current, 50kHz switching frequency and 30Hz full load bandwidth using FET device. Proposed system has two independent PWM controllers for each full-bridge switch leg drive and PI control loops for current regulations. It is shown experimental results that good step response of the current output.

• 전자공학회논문지A
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• 제30A권3호
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• pp.88-94
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• 1993

In this paper, a simple Ebers-Moll Model for the heterojunction bipolar transistor is presented. Using the model structure for the npn type HBT, the current-voltage characteristics was analyzed. And from the obtained terminal currents, the Ebers-Moll equations were derived. Then substituting the physical parameters for heterojunction to those for homojunction, this model would be used to analyze the characteristics of single and/or duble heterojunction HBT's. And directly relating model parameters to device parameters, it would be also used to optimize the characteristics of HBT's. The simulated results using this model were in good agreement with experimental data.

• 한국임상수의학회지
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• 제31권6호
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• pp.477-482
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• 2014

본 연구에서는 복강경을 이용한 고양이의 난소절제술에서 지혈 장치로서 $LigaSure^{TM}$와 양극 전기 응고 장치(bipolar)의 효과를 수술시간, 부작용에 대하여 비교해 보고자 하였다. 10마리의 고양이를 각각 5 마리씩 A군과 B군으로 무작위로 나누었고, A군은 좌측 난소는 $LigaSure^{TM}$로, 우측 난소는 양극 전기 응고 장치(bipolar)로 절제하였다. 반대로 B군은 좌측 난소는 양극 전기 응고 장치(bipolar)로, 우측 난소는 $LigaSure^{TM}$로 절제하였다. 수술은 three midline portals로 하였으며, 수술시간, Body Condition Score, ovarian pedicle fat과 부작용 등을 체크하였다. 그 결과, 총 수술시간은 평균 $24:18{\pm}6:36$분 이었으며, $LigaSure^{TM}$ ($1:24{\pm}0:59$ 분)가 양극 전기 응고 장치(bipolar) ($2:16{\pm}1:14$ 분, p = 0.021)에 비하여 난소절제에 유의적으로 더 짧은 시간이 걸렸다. BCS와 ovarian pedicle fat은 수술시간에 유의적인 영향을 미치지 않았으며, 부작용으로는 미약한 출혈, 복벽 손상, smoke 발생 등이 있었는데 수술시간에 유의적인 영향을 미치지 않았다. 이러한 결과들은 $LigaSure^{TM}$가 비교적 고가의 수술장비라는 단점이 있음에도 불구하고 복강경을 이용한 고양이의 난소절제술에 유용한 수술적 활용 방법이 될 수 있을 것이라는 것을 보여준다.

• 전기학회논문지
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• 제58권7호
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• pp.1363-1374
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• 2009

This paper reviews the characteristics and technical trends in Power MOSFET technology that are leading to improvements in power loss for power electronic system. The silicon bipolar power transistor has been displaced by silicon power MOSFET's in low and high voltage system. The power electronic technology requires the marriage of power device technology with MOS-gated device and bipolar analog circuits. The technology challenges involved in combining power handling capability with finger gate, trench array, super junction structure, and SiC transistor are described, together with examples of solutions for telecommunications, motor control, and switch mode power supplies.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1992년도 하계학술대회 논문집 B
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• pp.1126-1128
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• 1992

The object of this study is the design of 3 phase on-board inverter. The key point in the inverter design is the selection of switching device, and its performance effects that of total system. In this study, six-step square wave inverter was designed using IGBT ( Insulated Gate Bipolar Transistor ) which has the advantages of MOSFET and bipolar transistor as switching device. The condition of being small and light which is the one of requirements for on-board equipment was accomplished by using IGBT module and optimising the snubber circuit, and the reliablity was increased. It is confirmed that the designed inverter satisfies the required performance through the performance and environment test.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1995년도 추계학술대회 논문집
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• pp.158-162
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• 1995

We report rf and power characteristics of AlGaAs/GaAs Heterojunction Bipolar Transistor (HBTs) for X-band power applications. HBTs have been fabricated with polyimide a an interlayer dielectric. By characterizing the DC and RF characteristics we obtained the maximum current gain of 45, BV$\_$CEO/ of 10 V, fT of 30 GHz and f$\_$max/ of 17 GHz for device with 6x14$\mu\textrm{m}$$^2$emitter size. To extract accurate equivalent parameters, the De-embedded method was applied for extraction of parasitic parameters and the calculation of circuit equations for intrinsic parameters. Based on the Load-pull method, power characteristics was simulated and measured to get the maximum output power of the device.

• 한국산학기술학회:학술대회논문집
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• 한국산학기술학회 2004년도 춘계학술대회
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• pp.172-175
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• 2004

This paper analyzes the effects of Ge profiles shape of SiGe heterojunction bipolar transistors (HBT's) for high frequency application. Device simulations using ATLAS/BLAZE for the SiGe HBT with trapezoidal or triangular Ge profile are carried out to optimize the device performance. An HBT with $15\%$ triangular Ge profile shows higher cut-off frequency and DC current gain than that with $19\%$ trapezoidal Ge profile. The cut-off frequency and DC gain are increased from 42GHz to 84GHz and from 200 to 600, respectively. The SiGe HBT has been fabricated using a production CVD reactor.

• Nuclear Engineering and Technology
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• 제55권11호
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• pp.4238-4245
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• 2023

In order to predict the lifetime of InP Heterojunction Bipolar Transistor (HBT) devices and related circuits in the space radiation environment, a novel model including gamma radiation effects is proposed in this paper. Based on the analysis of radiation-induced device degradation effects including both DC and AC characteristics, a set of empirical expressions describing the device degradation trend are presented and incorporated into the Keysight model. To validate the effective of the proposed model, a series of radiation experiments are performed. The correctness of the novel model is validated by comparing experimental and simulated results before and after radiation.