• JSTS:Journal of Semiconductor Technology and Science
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• 제14권5호
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• pp.673-681
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• 2014

In this paper, a novel low specific on-resistance SOI LDMOS Device with P+P-top layer in the drift region is proposed and investigated using a two dimensional device simulator, MEDICI. The structure is characterized by a heavily-doped $P^+$ region which is connected to the P-top layer in the drift region. The $P^+$ region can modulates the surface electric field profile, increases the drift doping concentration and reduces the sensitivity of the breakdown voltage on the geometry parameters. Compared to the conventional D-RESURF device, a 25.8% decrease in specific on-resistance and a 48.2% increase in figure of merit can be obtained in the novel device. Furthermore, the novel $P^+P$-top device also present cost efficiency due to the fact that the $P^+$ region can be fabricated together with the P-type body contact region without any additional mask.

• 한국건설관리학회논문집
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• 제4권2호
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• pp.109-117
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• 2003

건설사업은 그 규모와 복잡성으로 인하여 다른 산업에 비해 위험에 대한 노출수위가 크고, 그 형태도 다양하다. 따라서, 건설사업에서 위험을 인지하고 대응하는 일련의 위험관리 과정은 정확하고 체계적으로 수행되어야 한다. 위험관리 과정에서 위험인지 단계는 다양한 위험요인의 인지와 그 위험의 성격을 규정하는 단계이고. 이러한 위험인지 단계에서 위험분류체계는 사업에 내재된 다양한 위험을 인지하게 해주는 유용한 도구이다. 본 연구에서는 기존 위험분류체계의 문제점을 개선하고 재정립함으로서, 실질적인 건설사업에서 위험인지 도구로서 활용될 수 있는 사업단계별, 계약주체별 체크리스트를 제안하였다.

• 한국정보통신학회논문지
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• 제5권1호
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• pp.157-165
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• 2001

집적 쇼트키 논리 게이트에서 전압 스윙을 크게 하기 위해서 백금 실리사이드 쇼트키 접합의 전기직 특성을 분석하였고, 이 접합에서 프로그램으로 특성을 시뮬레이션 하였다. 분석특성 특성을 위한 시뮬레이션 프로그램은 제조 공정용 SUPREM V와 모델링용 Matlab, 소자 구조용의 Medichi 툴이다. 시뮬레이션 특성을 위한 입력 파라미터는 소자 제작 공정의 공정 단계와 동일한 조건으로 하였다. 분석적인 전기적인 특성들은 순방향 바이어스에서 턴-온 전압, 포화 전류, 이상인자이고, 역방향 바이어스에서 항복 전압을 실제 특성과 시뮬레이션 특성 사이의 결과를 보였다. 결과로써 순방향 턴-온 전압, 역방향 항복전압, 장벽 높이는 기판의 증가된 농도의 변화에 따라 감소되었지만, 포화전류와 이상인자는 증가되었다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2010년도 하계학술대회 논문집
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• pp.337-337
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• 2010

갈륨-질화물 (GaN) 기반의 고 전자 이동도 트랜지스터 (High Electron Mobility Transistor, HEMT)는 GaN의 큰 밴드갭 (3.4~6.2 eV), 높은 항복전계 (Ec~3 MV/cm) 및 높은 전자 포화 속도 (saturation velocity $-107\;cm{\cdot}s-1$) 특성과 AlGaN/GaN 등과 같은 이종접합구조(Heterostructure )로부터 발생하는 높은 면밀도(Sheet Concentration)를 갖는 이차원 전자가스(Two-Dimensional Electron Gas, 2DEG) 채널로 인해 차세대 고출력/고전압 소자로서 각광받고 있다. 하지만 드레인 쪽의 게이트 에지부분에 집중되는 전계로 인한 애벌린치 할복현상(Breakdown)이 발생하는 문제점이 있다. 따라서 AlGaN/GaN HEMT의 항복전압 향상을 위한 방법으로 필드플레이트(Field-Plate) 구조가 많이 사용되고 있다. 본 논문에서는 2D 시뮬레이션을 통한 AlGaN/GaN HEMT의 필드플레이트 구조 최적화를 수행하였다. 이를 위해 ATLASTM 전산모사 프로그램을 이용하여 필드플레이트 길이, 절연체 증류 및 두께에 따른 전류 전압 특성 및 전계 분산효과에 대한 전산모사를 수행하여 그 결과를 비교, 분석 하였다, 이를 바탕으로 기존의 구조에 비해 약 300%이상 향상된 항복전압을 갖는 AlGaN/GaN HEMT의 최적화된 필드 플레이트 구조를 제안하였다.

• 전자공학회논문지A
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• 제28A권10호
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• pp.821-829
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• 1991

In this paper, a BICMOS technology that has CMOS devices for digital application and bipolar devices for high voltage (80V) analog applications is presented. Basic concept to design BICMOS device is simple process technology without making too many performance trade-offs. The base line process is poly gate p-well CMOS process and three additional masking steps are added to improve bipolar characteristics. The key ingredients of bipolar integration are n+ buried layer process, up/down isolation process and p-well base process. The bipolar base region is formed simultaneously with the region of CMOS p-well area to reduce mask and heat cycle steps. As a result, hFE value of NPN bipolar transistor is 100-150(Ic=1mA). Collector resistance value is 138 ohm in case of bent type collector structure. Breakdown voltage of BVebo, BVcbo and BVceo are 21V, 115V and78V respectively. Threshold voltage is ${\pm}$1.0V for NMOS and PMOS transistor. Breakdown voltage of NMOS and PMOS transistor is obtained 22V and 19V respectively. 41 stage CMOS ring oscillator has 0.8ns delay time.

• 전자공학회논문지D
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• 제35D권7호
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• pp.72-78
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• 1998

This paper is focused on the fabrication of reliable novel antifuse, which could operate at low voltage along with the improvement in OFF and ON-state properties. The fabricated antifuse consists of Al/BaTi$_{2}$O$_{3}$/SiO$_{2}$/TiW-silicide structure. Through the systematic analyses for bottom metal and the intermetallic insulator, material and electri cproperties were investiaged. TiW-silicide as the bottom electrode had smooth surface with average roughness of 11.angs. at 10X10.mu.m$^{2}$ and was bing kept as-deposited SiO$_{2}$ film stable. Amorphous BaTi$_{2}$O$_{3}$ film as the another insulator was chosen because of its low breakdown strength (2.5MV/cm). breakdown voltage of antifuse is remarkably reduced by using BaTi$_{2}$O$_{3}$ film, and leakage current of that maintained low level due to the SiO$_{2}$ film. Low ON-resistance (46.ohm./.mu.m$^{2}$) and low programming voltage(9.1V) can be obtained in theses antifuses with 220.angs. double insulator layer and 19.6X10$^{-6}$ cm$^{2}$ area, while keeping sufficient OFF-state reliability (less than 1nA).

• 한국자동차공학회논문집
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• 제15권3호
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• pp.166-173
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• 2007

A numerical study was conducted to have the effect of $CO_2$ addition to fuel on the chemical reaction mechanism with the change of the initial concentration of $CO_2$ and the axial velocity gradient. From this study, it was found that there were two serious effects of $CO_2$ addition on a non-premixed flame ; a diluent effect by the reactive species reduction and chemical effect of the breakdown of $CO_2$ by the third-body collision and thermal dissociation. Especially, the chemical effect was serious at the lower velocity gradient of the axial flow. It was certain that the mole fraction profile of $CO_2$ was deflected and CO was increased with the initial concentration of $CO_2$. It was also ascertained that the breakdown of $CO_2$ would cause the increasing of CO mole fraction at the reaction region. It was also found that the addition of $CO_2$ did not alter the basic skeleton of $H_2-O_2$ reaction mechanism, but contributed to the formation and destruction of hydrocarbon products such as HCO. The conversion of CO was also suppressed and $CO_2$ played a role of a dilution in the reaction zone at the higher axial velocity gradient.

• 한국식품영양과학회지
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• 제28권1호
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• pp.178-190
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• 1999

This study was conducted to develop a simulation model for the growth dynamics of pigs and to describe quantitatively protein deposition depending on the amino acid composition of feed protein. In the model it is assumed that the essential processes that determine the utilization of feed protein in the whole body are protein synthesis, breakdown of protein, and oxidation of amino acid. Besides, it is also assumed that occurrence of protein deposition depends on genetic potential and amino acid composition of feed protein. The genetic potential for the protein deposition is the maximum capacity of protein synthesis, being dependent on the protein mass of the whole body. To describe the effect of amino acid composition of feed on the protein deposition, a factor, which consist of ten amino acid functions and lie between 0 and 1, is introduced. Accordingly a model was developed, which is described with 15 flux equations and 11 differential equations and is composed of two compartments. The model describes non linear structure of the protein utilization system of an organism, which is in non steady state. The objective function for the simulation was protein deposition(g/day) cal culated according to the empirical model, PAF(product of amino acid functions) of Menke. The mean of relative difference between the simulated protein deposition and PAF calculated values, lied in a range of 11.8%. The simulated protein synthesis and breakdown rates(g/day) in the whole body showed a parallel behavior in the course of growth.

• 대한토목학회논문집
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• 제37권2호
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• pp.419-425
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• 2017

다양한 시설의 건설, 다수 이해관계자의 참여, 긴 사업기간 등의 복잡성으로 인해 대규모 건설프로젝트는 이를 관리함에 있어 어려움이 있다. 효과적인 대규모 프로젝트관리를 위해서는 합리적인 진도율 측정이 중요하고, 이를 위한 다양한 방법들이 제안되었다. 하지만 기존의 방법들은 단일 또는 일부 시설의 건설 프로젝트로 한정하였기 때문에 다양한 시설들을 건설하는 대규모 프로젝트에 적용하는 데 한계가 있다. 따라서 본 연구는 대규모 건설프로젝트의 특성을 반영한 진도율 측정 프레임워크를 제안함을 목표로 한다. 프레임워크는 작업분류체계 개발, 주요시설별과 하위시설별 가중치 산정, 통합 진도율 산정으로 총 4가지 단계로 이루어져 있다. 본 프레임워크를 검증하기 위해서 세종시를 대상으로 사례연구를 수행하였고, 활용 가능성을 검증할 수 있었다. 본 연구를 바탕으로 대규모 건설프로젝트의 진도율을 보다 합리적으로 측정할 수 있고 효과적인 프로젝트관리가 이루어질 것으로 기대된다.

• 제어로봇시스템학회논문지
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• 제7권8호
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• pp.689-696
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• 2001

Large-scale Multi-disciplinary Systems(LMS) such as transportation, aerospace, defense etc. are complex systems in which there are many subsystems, interfaces, functions and demanding performance requirements. Because many contractors participate in the development, it is necessary to apply methods of sharing common objectives and communicating design status effectively among all of the stakeholders. The processes and methods of systems engineering which includes system requirement analysis; functional analysis; architecting; system analysis; interface control; and system specification development provide a success-oriented disciplined approach to the project. This paper shows not only the methodology and the results of model-based systems engineering to Automated Guided Transit(AGT) system as one of LMS systems, but also propose the extension of the model-based tool to help manage a project by linking WBS (Work Breakdown Structure), work organization, and PBS (Product Breakdown Structure). In performing the model-based functional analysis, the focus was on the operation concept of an example rail system at the top-level and the propulsion/braking function, a key function of the modern automated rail system. The model-based behavior analysis approach that applies a discrete-event simulation method facilitates the system functional definition and the test and verification activities. The first application of computer-aided tool, RDD-100, in the railway industry demonstrates the capability to model product design knowledge and decisions concerning key issues such as the rationale for architecting the top-level system. The model-based product design knowledge will be essential in integrating the follow-on life-cycle phase activities. production through operation and support, over the life of the AGT system. Additionally, when a new generation train system is required, the reuse of the model-based database can increase the system design productivity and effectiveness significantly.