Extraction of Separated Source and Drain Resistances in Amorphous Indium–Gallium–Zinc Oxide TFTs Through <tex> $C$</tex>– <tex> $V$</tex> Characterization

Hagyoul Bae,Sungchul Kim,Minkyung Bae,Ja Sun Shin,Dongsik Kong,Hyunkwang Jung,Jaeman Jang,Jieun Lee,Dae Hwan Kim,Dong Myong Kim IEEE 2011 IEEE electron device letters Vol.32 No.6

<P>Considering asymmetry caused by layout, process, and device degradation, separate extraction of the source and drain resistances, i.e., <I>RS</I> and <I>RD</I>, respectively, from the total resistance <I>R</I><SUB>TOT</SUB> is very important in the design, modeling, and characterization of amorphous indium-gallium-zinc oxide (a-IGZO) thin-film transistors (TFTs). Due to the insulated gate structure, however, separate extraction is difficult through direct-current <I>I</I>-<I>V</I> characterization. In this letter, we propose a simple and useful technique for separate extraction of <I>RS</I> from <I>RD</I> in a-IGZO TFTs through a two-terminal parallel-mode <I>C</I> -<I>V</I> technique. We experimentally verified the validity of the proposed technique by comparing the result with the source-to-drain resistance from the <I>I</I>-<I>V</I> characteristics.</P>

축에 의한 건축 공간 구성방법 및 효과에 관한 연구

배동식 ( Dongsik Bae ) 한국공간디자인학회 2015 한국공간디자인학회논문집 Vol.10 No.4

(연구배경 및 목적)현대문명의 발전은 인류사회를 분화시키고 전문화시켜 놓았으며, 기능의 분리주의에 따라 인간의 시·공간적 연속성을 분단시켜 인간성 상실을 초래하였다. 게다가 다종 다양화된 인간 사회가 요구하는 기호와 기능의 세분화로 인해, 음악·미술·건축과 같은 창조성과 관련된 분야는 하나의 양식을 거부할 정도로 다양성과 복잡성을 띠고 있다. 이러한 다원화현상으로 인해 현대 건축은 공간구성에서 상호간의 논리적 연계성이 확보되지 않은 채 모순된 입장들이 병존하게 됨으로써 혼돈을 가중시키고 있다. 건축공간에 질서를 부여하는 하나의 방법으로서 내적인 질서를 추구하는 축의 구성원리를 파악하여 각 단위공간 및 공간결합시 발생되는 의미의 차이가 축에 의해 체계적으로 구성되는 방법과 효과를 분석하여 공간디자인 계획 시 필요한 기초자료를 제시함에 그 목적이 있다. (연구방법)본 연구는 인간의 시지각 심리 이론을 바탕으로 하여 건축의 형태적 측면이나 외부공간 보다는 내부공간에 있어서 축에 의한 공간 구성의 방법 및 효과를 파악하는 것이다. 연구의 진행은 다음과 같다. 인간 행동의 기준 단계로서 중요성을 갖는 지각심리의 특성을 고찰하여 시지각의 균형과 질서의 특성을 정리한다. 다음으로 건축공간의 지각특성을 통해 공간의 한정과 질서에 대하여 살펴본다. 공간구성에 질서를 형성시키는 원리로서의 축의 개념과 기본요소 및 타 구성원리에 의한 축의 표현특성을 정리한다. 건축공간 구성의 단계로 단위공간에서 바닥, 벽, 천정, 기둥, 빛 요소의 상호관계를 살펴보고, 질서 형성을 위한 공간 결합 방법을 파악한다. 건축공간에 있어서 축에 의해 구성되는 방법을 원형에 의한구성과 변환에 의한 구성으로 나누어 각 구성방법을 알아보고 이러한 구성에 의해서 나타나는 효과를 건축의 기본목표와도 일치하는 세가지, 즉 기능적, 상징적, 심리적 측면에서의 효과로 분류하여 진행한다. (결과)이와 같은 기준으로 작품분석을 한 결과, 동선에 의한 공간 구성의 효과는 합리적인 원리에 의해 실용성을 중시한 경우에 해당하는 기능적 측면, 즉 공간체계의 효율성, 단위공간의 배분에 있어서 적절성을 이룰 수 있다. 상징적 측면에서는 스케일감에 의한 공간의 심리적 효과를 나타내는 주공간의 창조와 이용자가 목적 공간에 이르게 하는 수단으로서의 내부공간에서의 초점, 기억의 보존과 영속성을 나타내고 있다. 심리적 측면에서는 목적 공간으로 이동시 기존의 인식을 통해 다음의 공간을 예측하여 심리적인 안정감을 주며, 공간에 위치한 시각적 대상물이나 개구부 또는 빛의 인력에 의해 목적 공간으로의 진입이 용이한 효과를 가진다. (결론)축에 의해 공간이 구성되는 방법과 효과를 밝혀 건축공간을 질서있게 계획할 수 있는 기본적인 틀을 제시함으로서 현대건축의 다원화, 다양화 속에서 건축공간의 무질서를 방지하고 체계적적인 질서를 구축시키는 방법으로서의 역할을 할 것이라고 생각된다. (Background and Purpose)The evolution of modern civilization has divided and specialized human society, and has causedloss of humanity by dividing space-time continuity of human. Moreover, due to the segmentation of preferences and functions within this diversified human society, fields related to creativity, such as music, art, and architecture, have also diversified and become more complex, with many types of form. Because of this diversification, there is a great deal of contrariety within modern architecture, with a lack of logical connectivity in space compositions, which can cause chaos. This study aims to present base data for a Space design plan. As one of the methods used to consider architecture spaces, we refer to the axis composition principle, which pertains to internal order, and analyze the methods and effects of differences in meaning revealed by the axis when unit spaces and combination spaces are used. (Method) This study aims to identify the methods used within, and effects of, space composition using an axis for the internal space, instead of applying this only to external space or using the architecture’s formative aspects based on visual perception theories. The process used is as follows: By considering perceptual psychological characteristics, which are significant as they are a standard part of human behavior, we arrange the balance and order characteristic of the visual perception. We then look at space limitations and order with reference to the perceptual characteristics of architecture spaces. We consider the concept of axes as the principle that creates order within space composition, and look at the expression characteristics of axes in terms of their basic elements or other composition principles. We also focus on the interrelation between the floor, wall, ceiling, pillars, and light within a unit of space as a step of architecture space, and identify the combinations of methods used for order formation within a space. We look at two composition methods using the axis approach, which include circle composition and conversion composition. We divide the effects of these compositions into three parts; that is, functional, symbolic, and psychological aspects, which are considered the basic goals of architecture. (Results) As a result of analyzing work based on the abovementioned standards, the effects of space composition by moving line impact the functional aspects, space efficiency, and unit space distribution when practicality is considered important. In terms of the symbolic aspect, it shows the main space creation that indicates space psychological effect by the scale, and as a means for user to get the target space, it has a focal point in internal space, preservation, permanency of the memory. With regard to the psychological aspect, psychological stability is provided when existing knowledge is used to predict the next space when moving into the target space. This facilitates movement into the target space in relation to the entrance area, visual objects located within the space, or light gravitation. (Conclusions) We expect this study to contribute to the formation of a systematic order for architecture spaces, and minimize issues by presenting a basic line on which to plan architectural spaces after clarifying the method and the effect of the way the space is composed on the axes.

The Effect of the Active Layer Thickness on the Negative Bias Stress-Induced Instability in Amorphous InGaZnO Thin-Film Transistors

Dongsik Kong,Hyun-Kwang Jung,Yongsik Kim,Minkyung Bae,Yong Woo Jeon,Sungchul Kim,Dong Myong Kim,Dae Hwan Kim IEEE 2011 IEEE electron device letters Vol.32 No.10

<P>The effect of the active layer thickness (<I>T</I><SUB>IGZO</SUB>) on the negative bias stress (NBS)-induced threshold voltage shift (Δ<I>VT</I>) in amorphous InGaZnO (a-IGZO) thin-film transistors (TFTs) is investigated and explained by using a subgap density-of-states (DOS) model. The NBS-induced negative Δ<I>VT</I> in a-IGZO TFT with a thinner <I>T</I><SUB>IGZO</SUB> is larger than that with a thicker <I>T</I><SUB>IGZO</SUB>. Based on the simulation result with the subgap DOS model, it is concluded that the <I>T</I><SUB>IGZO</SUB>-dependent Δ<I>VT</I> is originated from the accelerated creation of shallow donor states due to a higher surface electric field in a-IGZO TFTs with a thinner <I>T</I><SUB>IGZO</SUB>.</P>

Effect of the Active Layer Thickness on the Negative Bias Illumination Stress-induced Instability in Amorphous InGaZnO Thin-film Transistors

Dongsik Kong,Hyun Kwang Jung,Yongsik Kim,Minkyung Bae,Jaeman Jang,Jaehyeong Kim,Woojoon Kim,Inseok Hur,김동명,김대환 한국물리학회 2011 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.59 No.21

The effect of the active layer thickness (T_(IGZO) ) on the negative bias illumanation stress (NBIS)-induced threshold voltage shift (VT ) in amorphous InGaZnO (a-IGZO) thin-film transistors (TFTs) is investigated and explained by using a subgap density-of-states model. The NBIS-induced VT in a-IGZO TFT with a thinner T_(IGZO) is negatively larger than that in a-IGZO TFTs with a thicker T_(IGZO) . The T_(IGZO) -dependent VT is found to be caused by either hole trapping into the gate insulator near the interface or oxygen vacancy (Vo) ionization, which is activated more by a larger surface electric field EIGZO as T_(IGZO) becomes thinner.

Effect of the Active Layer Thickness on the Negative Bias Illumination Stress-induced Instability in Amorphous InGaZnO Thin-film Transistors

Kong, Dongsik,Jung, Hyunkwnag,Kim, Yongsik,Bae, Minkyung,Jang, Jaeman,Kim, Jeahyeong,Kim, Woojoon,Hur, Inseok,Kim, Dong Myong,Kim, Dae Hwan Korean Physical Society 2011 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.59 No.2

Analytical Models for Drain Current and Gate Capacitance in Amorphous InGaZnO Thin-Film Transistors With Effective Carrier Density

Minkyung Bae,Yongsik Kim,Dongsik Kong,Hyun Kwang Jeong,Woojoon Kim,Jaehyeong Kim,Inseok Hur,Dong Myong Kim,Dae Hwan Kim IEEE 2011 IEEE electron device letters Vol.32 No.11

<P>Analytical drain current and gate capacitance models for amorphous InGaZnO (a-IGZO) thin-film transistors (TFTs) over sub- and above-threshold regions are proposed by adopting an effective carrier density for the dominant carrier density. The effective carrier density fully considers the free carriers in the conduction band, the localized subgap deep states, and tail states over the bandgap for analytical <I>I</I>-<I>V</I> and <I>C</I>-<I>V</I> characteristics. The proposed analytical models are verified by comparing the measured <I>I</I>-<I>V</I> and <I>C</I>-<I>V</I> characteristics. The proposed models make a time-efficient simulation of a-IGZO TFT-based circuits possible due to their analytical form.</P>

부산지역 대학의 디자인 입시 실기과목 변화 연구

배진흥(Bae, Jinheung),홍동식(Hong, Dongsik) 한국디자인학회 2018 한국디자인학회 학술발표대회 논문집 Vol.2018 No.11

자연모사 기반 광대역 새싹 안테나 설계

우동식(Dongsik Woo),배성현(Sunghyun Bae) 한국전기전자학회 2020 전기전자학회논문지 Vol.24 No.2

본 논문에서는 광대역 지향성 방사패턴을 가지는 자연에서 영감을 얻은 새싹 모양 안테나를 제안한다. 모션감지 센서 응용을 위해 넓은 빔폭을 가지는 새싹 모양의 기울어진 방사체를 설계하였다. 확장된 잘려진 접지면을 반사기로 작용하도록 하여 지향성 방사패턴을 가지도록 하였다. 평형 방사체를 급전하기 위하여 우수한 진폭 및 위상 평형도를 가지는 광대역 발룬을 활용하였다. 제안된 안테나는 8.5에서 14.5 GHz의 넓은 주파수 대역폭과 넓은 빔폭을 가졌으며, 방사 효율은 90% 정도이었다. 측정된 이득은 4에서 5dBi이며, 전후방비는 10~20dB이었다. 제안된 안테나는 광대역 넓은 빔폭과 지향성 방사패턴을 요구하는 이미징 센서, 위상 배열 시스템 및 레이더 등에 활용될 수 있음을 보였다. This paper presents a nature-inspired wideband sprout-leaf shaped antenna with end-fire radiation pattern. A sprout-leaf shape angled-radiator was designed for wide beamwidth radiation patterns for motion detection sensors. An extended and truncated ground plane was used as a reflector for end-fire radiation patterns. To feed the balanced radiator, a broadband microstrip (MS) to coplanar stripline (CPS) balun was utilized with excellent amplitude and phase balance. The proposed antenna demonstrates wide frequency bandwidth from 8.5 to 14.5 GHz with wide beamwidth and the radiation efficiency of 90%. The measured gain is from 4 to 5 dBi and front-to-back ratio was 10 to 20 dB. It has been shown that the proposed antenna can be used for imaging sensors, phased array systems, and radars that require a wide bandwidth and a directional radiation pattern.

O₂분율에 따른 디젤 연소특성에 대한 수치적 연구

배재옥(Jaeok Bae),최낙원(Nakwon Choi),최민수(Minsu Choi),한동식(Dongsik Han),전충환(Chunghwan Jeon) 한국자동차공학회 2012 한국자동차공학회 부문종합 학술대회 Vol.2012 No.5

The object of this research is to analyze characteristics of diesel combustion on various O₂ fraction on numerical investigation with AVL-FIRE. It is the most important to understand characteristics of spray and combustion on various ambient gas composition in CVCC(constant volume combustion chamber) in the study of low temperature combustion of diesel engine. Gas compositions in CVCC for simulation each contain [O₂_21%], [O₂_16%, CO₂_5%], [O₂_11%, CO₂_10%] and fixed fraction [N₂_79%]. Numerical results are as follows : ignition delay time was decreased and flame temperature was increased when O₂ fraction was increased. Also grade on the curve of heat release rate was decreased when O₂fraction was decreased. The mass production of NO is reduced and that of Soot is increased definitely in condition of lower O₂ fraction.

디젤 엔진의 분사각 변화가 배기가스에 미치는 영향에 관한 수치해석적 연구

배명직(Myungjik Bae),이병화(Byounghwa Lee),한동식(Dongsik Han),전충환(Chunghwan Jeon),장영준(Youngjune Chang),송주헌(Juhun Song) 대한기계학회 2008 대한기계학회 춘추학술대회 Vol.2008 No.11

In order to reduce NOx and Soot emissions simultaneously , characteristics of diesel spray and combustion were investigated by numerical simulation with StarCD in this paper. This work focuses on effect of Spin Injection. A simulation model of combustion, spray and emissions is developed for heavy duty marine diesel engine application. Simulation is performed with change of spray angle between first and second directions at fixed engine speed, injection timing, injection duration and etc. The results show that Spin Spray Injection method can reduce NOx emission. And the results show that the 1st injection considerably interfere with 2nd injection characteristics.