• ETRI Journal
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• 제38권4호
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• pp.685-694
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• 2016

A surface micromachined piezoresistive pressure sensor with a novel internal substrate vacuum cavity was developed. The proposed internal substrate vacuum cavity is formed by selectively etching the silicon substrate under the sensing diaphragm. For the proposed cavity, a new fabrication process including a cavity side-wall formation, dry isotropic cavity etching, and cavity vacuum sealing was developed that is fully CMOS-compatible, low in cost, and reliable. The sensitivity of the fabricated pressure sensors is 2.80 mV/V/bar and 3.46 mV/V/bar for a rectangular and circular diaphragm, respectively, and the linearity is 0.39% and 0.16% for these two diaphragms. The temperature coefficient of the resistances of the polysilicon piezoresistor is 0.003% to 0.005% per degree of Celsius according to the sensor design. The temperature coefficient of the offset voltage at 1 atm is 0.0019 mV and 0.0051 mV per degree of Celsius for a rectangular and circular diaphragm, respectively. The measurement results demonstrate the feasibility of the proposed pressure sensor as a highly sensitive circuit-integrated pressure sensor.

• 한국전기전자재료학회논문지
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• 제25권1호
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• pp.6-14
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• 2012

For integrated complementary metal oxide semiconductor (CMOS) circuits, the lateral spread for two-dimensional (2-D) impurity distributions are very important for the analyzing the devices. The measured two-dimensional SEM data obtained using the chemical etching-method matched very well with the results of the Gauss model for boron implanted samples. But the profiles in boron implanted silicon were deviated from the Gauss model. The profiles in boron implanted silicon were shown a little bit steep profile in the deep region due to backscattering effect on the near surface from the bombardments of light boron ions. From the simulated 3-D data obtained using an analytical model, the 1-D and 2-D data were compared with the experimental data and could be verified the justification from the experimental data. The data of 3-D model were also shown good agreements with the experimental and the simulated data. It can be used in the 3-D chip design and the analysis of microelectro-mecanical system (MEMS) and special devices.

• 한국전기전자재료학회논문지
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• 제27권1호
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• pp.61-69
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• 2014

In this paper, we have researched semiconductor optical filters to solve the problem of the high failure rate that are recognize bad of financial account, jam of financial account and the ATM service interruption due to failure of accurate location information among the operation of the ATM (automatic teller machine) systems. A semiconductor optical filters that have high resolution and less diffuse, high transmittance are able to detect the information of financial account surface accurately. Therefore, it is a stable filter that is able to minimize the incidence of disability. In this paper, we drew the determinants by element for implement an excellent semiconductor optical filters. Based on this, we had to be able to implement the semiconductor optical filter that is able to be mounted on the actual ATM system through future studies.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제6권1호
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• pp.229-240
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• 2012

Advances in MEMS and CMOS technologies have motivated the development of low cost/power sensors and wireless multimedia sensor networks (WMSN). The WMSNs were created to ubiquitously harvest multimedia content. Such networks have allowed researchers and engineers to glimpse at new Machine-to-Machine (M2M) Systems, such as remote monitoring of biosignals for telemedicine networks. These systems require the acquisition of a large number of data streams that are simultaneously generated by multiple distributed devices. This paradigm of data generation and transmission is known as event-streaming. In order to be useful to the application, the collected data requires a preprocessing called data fusion, which entails the temporal alignment task of multimedia data. A practical way to perform this task is in a centralized manner, assuming that the network nodes only function as collector entities. However, by following this scheme, a considerable amount of redundant information is transmitted to the central entity. To decrease such redundancy, data fusion must be performed in a collaborative way. In this paper, we propose a collaborative data alignment approach for event-streaming. Our approach identifies temporal relationships by translating temporal dependencies based on a timeline to causal dependencies of the media involved.

• 센서학회지
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• 제28권2호
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• pp.127-132
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• 2019

In this study, the fabrication of through-silicon vias (TSVs) filled with SWNTs/Sn by utilizing surface/bulk micromachining and MEMS technologies is proposed. Tin (Sn) and single-walled nanotube (SWNT) powders are used as TSV interconnector materials in the development of a novel TSV at low temperature. The measured resistance of a TSV filled with SWNT/Sn powder is considerably reduced by increasing the fraction of Sn and is lower than that of a TSV filled with only Sn. This is because of a decrease in the surface scattering of electrons along with an increase in the grain size of sintered SWNTs/Sn. The proposed method is conducted at low temperatures (< $400^{\circ}C$) due to the low melting temperature of Sn; hence, the proposed TSVs filled with SWNTs/Sn can be utilized in CMOS based applications.

• 대한전자공학회논문지SD
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• 제41권12호
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• pp.27-34
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• 2004

최근 실리콘 미세공정의 발달로 상용화된 0.2$\mum$ 게이트길이 이하의 deep submicron MOSFET 출력특성을 정확히 모델링하기 위해서는 RF 기판 회로 연구가 필수적이다. 먼저 본 논문에서는 기판 캐패시던스와 기판 저항이 병렬로 연결된 모델과 기판 저항만을 사용한 단순 모델들에 적합한 직접 추출 방법을 각각 개발하였다. 이 추출방법들을 0.15$\mum$ CMOS 소자에 적용한 결과 단순 모델보다 RC 병렬 기판모델이 측정된 $Y_{22}$-parameter에 30GHz까지 더 잘 일치하는 것을 확인하였으며, 이는 RC 병렬 기판모델 및 직접추출방법의 RF 정확도를 증명한다. 이러한 RC 병렬 기판모델을 사용하여 게이트 길이를 0.11에서 0.5$\mum$까지 변화시키고 드레인 전압을 0에서 1.2V까지 증가시키면서 기판 모델 파라미터들의 bias 종속 특성과 게이트 길이 종속 특성을 새롭게 추출하였다. 이러한 새로운 추출 결과는 scalable한 RF 비선형 기판 모델 개발에 유용하게 사용될 것이다.

• 대한전자공학회논문지SD
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• 제43권11호
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• pp.48-57
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• 2006

본 설계에서는 최근 부상하고 있는 motor control, 3-phase power control, CMOS image sensor 등 각종 센서 응용을 위해 고해상도와 저전력, 소면적을 동시에 요구하는 12b 200KHz 0.52mA $0.47mm^2$ 알고리즈믹 ADC를 제안한다. 제안하는 ADC는 요구되는 고해상도와 처리 속도를 얻으면서 동시에 전력 소모 및 면적을 최적화하기 위해 파이프라인 구조의 하나의 단만을 반복적으로 사용하는 알고리즈믹 구조로 설계하였다. 입력단 SHA 회로에서는 고집적도 응용에 적합하도록 8개의 입력 채널을 갖도록 설계하였고, 입력단 증폭기에는 folded-cascode 구조를 사용하여 12비트 해상도에서 요구되는 높은 DC 전압 이득과 동시에 층L분한 위상 여유를 갖도록 하였다. 또한, MDAC 커패시터 열에는 소자 부정합에 의한 영향을 최소화하기 위해서 인접 신호에 덜 민감한 3차원 완전 대칭 구조의 레이아웃 기법을 적용하였으며, SHA와 MDAC 등 아날로그 회로에는 향상된 스위치 기반의 바이어스 전력 최소화 기법을 적용하여 저전력을 구현하였다. 기준 전류 및 전압 발생기는 칩 내부 및 외부의 잡음에 덜 민감하도록 온-칩으로 집적하였으며, 시스템 응용에 따라 선택적으로 다른 크기의 기준 전압을 외부에서 인가할 수 있도록 설계하였다. 또한, 다운 샘플링 클록 신호를 통해 200KS/s의 동작뿐만 아니라, 더 적은 전력을 소모하는 10KS/s의 동작이 가능하도록 설계하였다. 제안하는 시제품 ADC는 0.18um n-well 1P6M CMOS 공정으로 제작되었으며, 측정된 DNL과 INL은 각자 최대 0.76LSB, 2.47LSB 수준을 보인다. 또한 200KS/s 및 10KS/s의 동작 속도에서 SNDR 및 SFDR은 각각 최대 55dB, 70dB 수준을 보이며, 전력 소모는 1.8V 전원 전압에서 각각 0.94mW 및 0.63mW이며, 시제품 ADC의 칩 면적은 $0.47mm^2$ 이다.

• Journal of Information Display
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• 제8권2호
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• pp.10-14
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• 2007

A blazed $GxL^{TM}$ device is described as having high optical efficiency (> 70% for RGB lasers), and high contrast ratio (> 10,000:1), and that is highly reliable when used in a large-area laser projection system. It has a robust design and precise stress control technology to maintain a uniform shape (bow and tilt) of more than 6,000 ribbons, a $0.25-{\mu}m$ CMOS compatible fabrication processing and planarization techniques to reduce fluctuation of the ribbons, and a reliable Al-Cu reflective film that provided protection against a high-power laser. No degradation in characteristics of the GxL device is observed after operating a 5,000- lumen projector for 2,000 hours and conducting 2,000 temperature cycling tests at $-20^{\circ}C$ and $+80^{\circ}C$. At the 2005 World Exposition in Aichi, Japan the world's largest laser projection screen with a size of 2005 inches (10 m ${\times}$ 50 m) and 6 million pixels (1,080 ${\times}$ 5,760) was demonstrated.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2013년도 추계학술대회 논문집
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• pp.763-764
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• 2013

A three-dimensional image capturing device and its signal processing algorithm and apparatus are presented. Three dimensional information is one of emerging differentiators that provides consumers with more realistic and immersive experiences in user interface, game, 3D-virtual reality, and 3D display. It has the depth information of a scene together with conventional color image so that full-information of real life that human eyes experience can be captured, recorded and reproduced. 20 Mega-Hertz-switching high speed image shutter device for 3D image capturing and its application to system prototype are presented[1,2]. For 3D image capturing, the system utilizes Time-of-Flight (TOF) principle by means of 20MHz high-speed micro-optical image modulator, so called 'optical resonator'. The high speed image modulation is obtained using the electro-optic operation of the multi-layer stacked structure having diffractive mirrors and optical resonance cavity which maximizes the magnitude of optical modulation[3,4]. The optical resonator is specially designed and fabricated realizing low resistance-capacitance cell structures having small RC-time constant. The optical shutter is positioned in front of a standard high resolution CMOS image sensor and modulates the IR image reflected from the object to capture a depth image (Figure 1). Suggested novel optical resonator enables capturing of a full HD depth image with depth accuracy of mm-scale, which is the largest depth image resolution among the-state-of-the-arts, which have been limited up to VGA. The 3D camera prototype realizes color/depth concurrent sensing optical architecture to capture 14Mp color and full HD depth images, simultaneously (Figure 2,3). The resulting high definition color/depth image and its capturing device have crucial impact on 3D business eco-system in IT industry especially as 3D image sensing means in the fields of 3D camera, gesture recognition, user interface, and 3D display. This paper presents MEMS-based optical resonator design, fabrication, 3D camera system prototype and signal processing algorithms.

• 한국지구과학회지
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• 제34권6호
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• pp.588-601
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• 2013

최근 지구물리 물리탐사 분야에서 경사각과 방위각 정보는 시추공 물리검층 및 물리탐사 자료보정을 위한 시추공 편차검층, 이동형 실시간 자료획득 시스템, 기타 지구물리 모니터링 시스템 등 다양하게 활용되면서 그 중요성이 높아지고 있다. 특히 최근 셰일가스의 개발이 가능하게 한 방향시추 기술에서도 경사각과 방위각 정보는 필수일 정도로 그 응용범위가 매우 넓다. 따라서 여러 분야에 응용될 수 있는 경사각과 방위각 측정 시스템의 초소형 옥외 저전력 운용이 절실해졌다. 본 논문에서는 최신 CMOS 저전력, 고성능 MCU 및 멤스(MEMS) 자세방위기준장치(AHRS)를 도입하여 초소형, 저전력으로 제작된 다용도 야외시험용 실시간 경사각과 방위각 연속 측정 시스템 개발 연구의 결과를 제시하고자 한다. 시스템은 최소 지름 42 mm의 존데 내에 설치될 수 있도록 초슬림 형태로 제작되었으며 실시간 데이터 획득이 가능할 뿐만 아니라 엔코더, DGPS 연동으로 운용 확장이 가능하여 다양한 응용이 기대된다.