• JSTS:Journal of Semiconductor Technology and Science
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• v.17 no.2
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• pp.230-238
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• 2017

We have proposed an InGaAs-based gate-all-around (GAA) tunneling field-effect transistor (TFET) with a stacked dual-metal gate (DMG). The electrical performances of the proposed TFET are evaluated through technology computer-aided design (TCAD) simulations. The simulation results show that the proposed TFET demonstrates improved DC performances including high on-state current ($I_{on}$) and steep subthreshold swing (S), in comparison with a single-metal gate (SMG) TFET with higher gate metal workfunction, as it has a thinner source-channel tunneling barrier width by low workfunction of source-side channel gate. The effects of the gate workfunction on $I_{on}$, the off-state current ($I_{off}$), and S in the DMG-TFETs are examined. The DMG-TFETs with PNPN structure demonstrate outstanding DC performances and RF characteristics with a higher n-type doping concentration in the $In_{0.8}Ga_{0.2}As$ source-side channel region.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.506-508
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• 2005

In general, organic TFTs are comprised of four components: gate electrode, gate dielectric, organic active semiconductor layer, and source and drain contacts. The TFT current, in turn, is typically determined by channel length and width, carrier field effect mobility, gate dielectric thickness and permittivity, contact resistance, and biasing conditions. More recently, a number of techniques and processes have been introduced to the fabrication of OTFT circuits and displays that aim specifically at reduced fabrication cost. These include microcontact printing for the patterning of metals and dielectrics, the use of photochemically patterned insulating and conducting films, and inkjet printing for the selective deposition of contacts and interconnect pattern. In the fabrication of organic TFTs, microcontact printing has been used to pattern gate electrodes, gate dielectrics, and source and drain contacts with sufficient yield to allow the fabrication of transistors. We were fabricated a pentacene OTFTs on flexible PEN film. Au/Cr was used for the gate electrode, parylene-c was deposited as the gate dielectric, and Au/Cr was chosen for the source and drain contacts; were all deposited by ion-beam sputtering and patterned by microcontact printing and lift-off process. Prior to the deposition of the organic active layer, the gate dielectric surface was treated with octadecyltrichlorosilane(OTS) from the vapor phase. To complete the device, pentacene was deposited by thermal evaporation and patterned using a parylene-c layer. The device was shown that the carrier field effect mobility, the threshold voltage, the subthreshold slope, and the on/off current ratio were improved.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.47 no.4
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• pp.50-61
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• 2010

Nowadays, the SoC is watched by all over the world with interest. The design trend of the SoC is hardware and software co-design which includes the design of hardware structure in RTL level and the development of embedded software. Also the technology is toward deep-submicron and the observability of the SoC's internal state is not easy. Because of the above reasons, the SoC debug is very difficult and time-consuming. So we need a reliable debugger to find the bugs in the SoC and embedded software. In this paper, we developed a hardware debugger named OCD. It is based on IEEE 1140.1 JTAG standard. In order to verify the operation of OCD, it is integrated into the 32bit RISC processor - Core-A (Core-A is the unique embedded processor designed by Korea) and is tested by interconnecting with software debugger. When embedding the OCD in Core-A, there is 14.7% gate count overhead. We can modify the DCU which occupies 2% gate count in OCD to adapt with other processors as a debugger.

• Journal of the Korean Wood Science and Technology
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• v.46 no.3
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• pp.278-284
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• 2018

This study is for species identification for each structure member such as Pillar, Bo, Changbang, Dori, Jangyeo, Judu, Donjaju, Chunyeo, Guitle, and Jongdae, of Pungnammun Gate (Treasure 308). Jeonju is the birthplace of Joseon Dynasty and Pungnammun Gate was the southern gate of old Jeonjueupseong which was walled town. Provincial Governor of Koryeo Dynasty, Yu Gyeong Choi built Jeonjubuseong and four gates at all cardinal points in 1388. And the gate was burnt down by Jeongyujaeran (war with Japan in 1597). It was rebuilt by King Yeongjo (Joseon Dynasty) in 1734 and renamed 'Pungnammun' after 34 years. It was designated for Treasure 308 for its unique style of architecture and historic values in 1963. In this study, all of wooden structure members were Pinus spp.. This result was matched for the result of major species for wooden building of late Joseon Dynasty. It can be used to complete database for architecture of Castle's Gate and help for restoration of cultural heritage in the future.

• Journal of the Korean Institute of Telematics and Electronics C
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• v.35C no.4
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• pp.21-29
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• 1998

As silicon geometry shrinks into deep submicron and the operating speed icreases, higher accuracy is required in the analysis of the propagation delays of the gates and interconnects in an ASIC. In this paper, the driving characteristics of a CMOS gate is represented by a gatedriver model, consisting of a linear resistor $R_{dr}$ and an independent ramp voltage source $V_{dr}$ . We drivered $R_{dr}$ and $V_{dr}$ as the functions of the timing data representing gate driving capability and an effective capacitance $C_{eff}$ reflecting resistance shielding effect by interconnet circuits. Through iterative applications of these equations and AWE algorithm, $R_{dr}$ , $V_{dr}$ and $C_{eff}$ are comuted simulataneously. then, the gate delay is decided by $C_{eff}$ and the interconnect circuit delay is determined by $R_{dr}$ and $V_{dr}$ . this process has been implemented as an ASIC timing analysis program written in C language and four real circuits were analyzed. In all cases, we found less than 5% of errors for both of gate andinterconnect circuit delays with a speedup factor ranging from a few tens to a few hundreds, compared to SPICE.SPICE.

• Journal of architectural history
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• v.17 no.4
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• pp.25-42
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• 2008

The Gyeongbok Palace was completed during the reign of King Taejo and King Sejong in the early Joseon Dynasty. The most remarkable spacious feature of the palace is that it has an inner palace wall without an outer palace wall. The absence of the outer palace wall had its origin in the palace of the late Goryeo Dynasty which did not provide the outer palace wall. Gwanghwamoon was the main gate of the palace, and the office buildings of the Six Ministries were arranged on the right side in front of the main gate. A wide road called Six Ministries Avenue was made between the builidings. The avenue was completed during the reign of the third king of Joseon, Taejong, and it was assumed that this arrangement was influenced by the government office arrangements of Nanjing, the early capital city of the Ming Dynasty. Gwanghwamoon held national rituals as well as the civic and military state examinations nations in front of the gate. The avenue was decorated with flowers and silks when kings and the royal families, or Chinese envoys enter the gate, and the civilians watched the parade, Because there was no outer palace wall, all the events held at Gwanghwamoon and the Six Ministries Avenue ware opened to the public, it was the unique feature of Gyeongbok Palace that the palaces of Goryeo dynasty and China did not have.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.477-477
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• 2008

For more than three decades, the gate dielectrics in CMOS devices are $SiO_2$ because of its blocking properties of current in insulated gate FET channels. As the dimensions of feature size have been scaled down (width and the thickness is reduced down to 50 urn and 2 urn or less), gate leakage current is increased and reliability of $SiO_2$ is reduced. Many metal oxides such as $TiO_2$, $Ta_2O_4$, $SrTiO_3$, $Al_2O_3$, $HfO_2$ and $ZrO_2$ have been challenged for memory devices. These materials posses relatively high dielectric constant, but $HfO_2$ and $Al_2O_3$ did not provide sufficient advantages over $SiO_2$ or $Si_3N_4$ because of reaction with Si substrate. Recently, $HfO_2$ have been attracted attention because Hf forms the most stable oxide with the highest heat of formation. In addition, Hf can reduce the native oxide layer by creating $HfO_2$. However, new gate oxide candidates must satisfy a standard CMOS process. In order to fabricate high density memories with small feature size, the plasma etch process should be developed by well understanding and optimizing plasma behaviors. Therefore, it is necessary that the etch behavior of $HfO_2$ and plasma parameters are systematically investigated as functions of process parameters including gas mixing ratio, rf power, pressure and temperature to determine the mechanism of plasma induced damage. However, there is few studies on the the etch mechanism and the surface reactions in $BCl_3$ based plasma to etch $HfO_2$ thin films. In this work, the samples of $HfO_2$ were prepared on Si wafer with using atomic layer deposition. In our previous work, the maximum etch rate of $BCl_3$/Ar were obtained 20% $BCl_3$/ 80% Ar. Over 20% $BCl_3$ addition, the etch rate of $HfO_2$ decreased. The etching rate of $HfO_2$ and selectivity of $HfO_2$ to Si were investigated with using in inductively coupled plasma etching system (ICP) and $BCl_3/Cl_2$/Ar plasma. The change of volume densities of radical and atoms were monitored with using optical emission spectroscopy analysis (OES). The variations of components of etched surfaces for $HfO_2$ was investigated with using x-ray photo electron spectroscopy (XPS). In order to investigate the accumulation of etch by products during etch process, the exposed surface of $HfO_2$ in $BCl_3/Cl_2$/Ar plasma was compared with surface of as-doped $HfO_2$ and all the surfaces of samples were examined with field emission scanning electron microscopy and atomic force microscope (AFM).

• Journal of Communications and Networks
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• v.13 no.5
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• pp.481-493
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• 2011

Multiple-input multiple-output (MIMO) technology provides high data rate and enhanced quality of service for wireless communications. Since the benefits from MIMO result in a heavy computational load in detectors, the design of low-complexity suboptimum receivers is currently an active area of research. Lattice-reduction-aided detection (LRAD) has been shown to be an effective low-complexity method with near-maximum-likelihood performance. In this paper, we advocate the use of systolic array architectures for MIMO receivers, and in particular we exhibit one of them based on LRAD. The "Lenstra-Lenstra-Lov$\acute{a}$sz (LLL) lattice reduction algorithm" and the ensuing linear detections or successive spatial-interference cancellations can be located in the same array, which is considerably hardware-efficient. Since the conventional form of the LLL algorithm is not immediately suitable for parallel processing, two modified LLL algorithms are considered here for the systolic array. LLL algorithm with full-size reduction-LLL is one of the versions more suitable for parallel processing. Another variant is the all-swap lattice-reduction (ASLR) algorithm for complex-valued lattices, which processes all lattice basis vectors simultaneously within one iteration. Our novel systolic array can operate both algorithms with different external logic controls. In order to simplify the systolic array design, we replace the Lov$\acute{a}$sz condition in the definition of LLL-reduced lattice with the looser Siegel condition. Simulation results show that for LR-aided linear detections, the bit-error-rate performance is still maintained with this relaxation. Comparisons between the two algorithms in terms of bit-error-rate performance, and average field-programmable gate array processing time in the systolic array are made, which shows that ASLR is a better choice for a systolic architecture, especially for systems with a large number of antennas.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.303.1-303.1
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• 2014

좋은 전기적 특성을 가지면서 소자의 크기를 줄이기에 용이한 Gate-all-around (GAA) twin Si nanowire field-effect transistors (TSNWFETs)의 연구가 많이 진행되고 있다. Switching 특성과 단채널 효과가 없는 TSNWFETs의 특성은 GAA 구조의 본질적인 특성이다. TSNWFETs는 기존의 single Si nanowire TSNWFETs와 bulk FET에 비하여 Drive current가 nanowire의 지름에 많은 영향을 받지 않는다. 그러나 TSNWFETs의 전체 on-current는 훨씬 작고 nanowire의 지름이 작아지면서 줄어들게 되면서 소자의 sensing speed와 sensing margin 특성의 악화를 가지고 온다. GAA TSNWFETs의 제작 및 전기적 실험에 대한 연구는 많이 진행되었으나, GAA TSNWFETs의 전기적 특성에 대한 이론적 연구는 매우 적다. 본 연구에서는 GAA TSNWFETs의 nanowire 크기에 따른 전기적 특성을 관찰하였다. GAA TSNWFETs와 bulk FET의 전기적 특성을 양자역학을 고려하여 3차원 TCAD 시뮬레이션을 툴을 이용하여 계산하였다. GAA TSNWFETs와 bulk FET의 전류-전압 특성 계산을 통해 on-current 크기, subthreshold swing, drain-induced barrier lowering (DIBL), gate-induced drain leakage를 보았다. 전류가 흐르는 경로와 전기적 특성의 물리적 의미에 대한 연구를 위해 TSNWFETs에서의 전류 밀도, conduction band edge, potential 특성을 분석하였다. 시뮬레이션 결과를 통해 Switching 특성, 단채널 효과에 대한 면역 특성, nanowire의 단면적에 따른 전류 흐름을 보았다. nanowire의 크기가 작아지면서 DIBL이 증가하고 문턱전압과 전체 on-current는 감소하면서 소자의 특성이 악화된다. 이러한 결과는 GAA TSNWFETs의 전기적 특성을 이해하고 좋은 소자 특성을 위한 구조를 연구하는데 많은 도움이 될 것이다.

• Proceedings of the IEEK Conference
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• 2002.06b
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• pp.5-8
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• 2002

Hot carrier induced device degradation is observed in thin-film, gate-all-around SOI transistor under DC stress conductions. We observed the more significant device degradation in GAA device than general single gate SOI device due to the degradation of edge transistor. Therefore, it is expected that the maximum available supply voltage of GAA transistor is lower than that o( bulk MOSFET or single gale SOI device.