• Proceedings of the KIPE Conference
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• 1998.07a
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• pp.428-432
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• 1998

A passive energy recovery snubber for high-power-factor boost rectifier, in which the main switch is implemented with a MOSFET, is described in terms of the equivalent circuits that are operational during turn-on and turn-off sequences. The main switch combined with proposed snubber can be turned on with zero current and turned off at limited voltage stress. The high-power-factor boost rectifier with proposed snubber is implemented, and the experimental results are presented to confirm the validity of proposed snubber.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.384-384
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• 2012

We report nonvolatile memory properties of poly (3, 4-ethylenedioxythiophene) (PEDOT) thin films grown by vapor phase polymerization using FeCl3 as an oxidant. Liquid-bridge-mediated transfer method was employed to remove FeCl3 for generation of pure PEDOT thin films. From the electrical measurement of memory device, we observed voltage induced bipolar resistive switching behavior with ON/OFF ratio of 103 and reproducibility of more than 103 dc sweeping cycles. ON and OFF states were stable up to 104 seconds without significant degradation. Cyclic voltammetry data illustrates resistive switching effect can be attributed to formation and rupture of conducting paths due to oxidation and reduction of PEDOT. The maximum current before reset process was found to be increase linearly with increase in compliance current applied during set process.

• Proceedings of the IEEK Conference
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• 2000.06b
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• pp.111-114
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• 2000

Single Electron Transistor Logic (SETL) can be characterized by HSPICE simulation using a SPICE macro model. First, One unit SET is characterized by Monte-carlo simulation and then we fit SPICE macro-modeling equations to its characteristics. Second, using this unit SET, we simulate the transient characteristics of two-input NAND gate in both the static and dynamic logic schemes. The dynamic logic scheme shows more stable operation in terms of logic-swing and on/off current ratio. Also, there is a merit that we can use the SET only as current on-off switch without considering the voltage gain.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.28 no.7
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• pp.415-418
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• 2015

In this paper, $TiO_2$ based thin-film transistors (TFTs) were fabricated using by an atomic layer deposition with high aspect ratio and excellent step coverage. $TiO_2$ semiconducting layer was deposited showing a rutile phase through the rapid thermal annealing process, and exhibited TFT characteristics with a $200{\mu}m$ channel length of low-leakage currents (none of current flow during off-state), stable threshold voltages (-10 V ~ 0 V), and a much higher on/off current ratio (<$10^5$), respectively.

• 한국정보디스플레이학회:학술대회논문집
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• 2004.08a
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• pp.889-892
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• 2004

We developed a high performance bottom contact, organic thin-film transistor (OTFT) array on plastic using a self-organized process. The effect of OTS treatment on the PVP gate insulator for the performance of OTFT on plastic has been studied The OTFT without OTS exhibited a field-effect mobility of 0.1 $cm^2$/Vs on/off current ratio of > $10^7$. On the other hand, OTFT with OTS, exhibited a field-effect mobility of 1.3 $cm^2$/Vs and on/off current ratio of>$10^8$.

• Transactions on Electrical and Electronic Materials
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• v.12 no.2
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• pp.43-50
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• 2011

Carbon-nanotube metal oxide semiconductor field effect transistor (CN-MOSFET) is a promising future device candidate. The electrical characteristics of 16 nm N-type CN-MOSFETs are explored in this paper. The optimum N-type CN-MOSFET device profiles with different number of tubes are identified for achieving the highest on-state to off-state current ratio ($I_{on}/I_{off}$). The influence of substrate voltage on device performance is also investigated in this paper. Tradeoffs between subthreshold leakage current and overall switch quality are evaluated with different substrate bias voltages. Technology development guidelines for achieving high-speed, low-leakage, area efficient, and manufacturable carbon nanotube integrated circuits are provided.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.28 no.2
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• pp.145-156
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• 1995

Satellite infrared images were analyzed to study the distribution of eddies off the east coast of Korea from 1987 to 1991. Most of the eddies were filament-type and were generated near the fringe of the East Korea Warm Current (EKWC) flowing northward. Eddies having length of 20-40km and width of 10-20km were most abundant. The meso-scale eddies of 100-200km in diameter were found between Mukho and Wonsan Bay in almost all the images. There was no evidence for the consistent movement of eddies to a definite direction. The Ulleung Warm Eddy, although reported previously by the hydrographic data, could not be identified by the limited amount of infrared imagery.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.52 no.12
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• pp.632-640
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• 2003

In conventional Zero-Voltage-Transition(ZVT) PWM converters, zero-voltage turn-on and turn-off for main switch without increasing voltage/current stresses is achieved at a fixed frequency. The switching loss, stress, and noise, however, can't be minimized because they adopt auxiliary switches turned off under hard-switching condition. In this paper, new ZVS-PWM converters of which both active and passive switches are always operating with soft-switching condition are proposed. Therefore, the proposed ZVS-PWM converters are most suitable for avionics applications requiring high-power density. Breadboarded ZVS-PWM boost converters using power MOSFET are constructed to verify theoretical analysis.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.11 no.6
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• pp.388-395
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• 1986

Dispersion characteristics of shielded single, coupled and edge-offset microstrip structures are investigated by using hybrid mode analysis with Galerkin's method in the spectral domain. Two new basis functions for the longitudinal strip current are proposed and convergence rates of the solutions for the basis functions are compared. Current distribution of the coupled line is obtaind from that of the single line by using shift theorem of the Fourier transform. In addition, effects of off-centered inner strip conductor on dispersion are also discussed Numerical results include various structual parameters and are compared with other available data and good agreements are observed.

• Proceedings of the IEEK Conference
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• 2001.06b
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• pp.189-192
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• 2001

We have studied fabrication processes that form asymmetric $\Gamma$-gate with a 0.1${\mu}{\textrm}{m}$ gate length in MMIC's(Monolithic Microwave Integrated Circuits). Asymmetric $\Gamma$-gate was fabricated using mixture of PMMA and MCB. Thus pseudomorphic high electron mobility transistor (PHEMT's) with 0.1${\mu}{\textrm}{m}$ gate length was fabricated via several steps such as mesa isolation, metalization, recess, passivation. PHEMT's has the -1.75 V of pinch-off voltage (Vp), 63 mA of drain saturation current(Idss and 363.6 mS/mm of maximum transconductance (Gm) in DC characteristics and current gain cut-off frequency of 106 GHz and maximum frequency of oscillation of 160 GHz in RF characteristics.