• 센서학회지
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• 제31권4호
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• pp.271-277
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• 2022

We analyzed the effects of the interface trap on the output characteristics of an inversion mode n-channel GaN Schottky barrier (SB)-MOSFET based on the N_it distribution using TCAD simulation. As interface trap number density (N_it) increased, the threshold voltage increased while the drain current density decreased. Under N_it=5.0×10¹⁰ cm^-2 condition, the threshold voltage was 3.2 V for V_DS=1 V, and the drain current density reduced to 2.4 mA/mm relative to the non-trap condition. Regardless of the N_it distribution type, there was an increase in the subthreshold swing (SS) following an increase in N_it. Under U-shaped N_it distribution, it was confirmed that the SS varied depending on the gate voltage. The interface fixed charge (Q_f) caused an shift in the threshold voltage and increased the off-state current collectively with the surface trap. In summary, GaN SB-MOSFET can be a building block for high power UV optoelectronic circuit provided the surface state is significantly reduced.

• 센서학회지
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• 제12권4호
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• pp.149-155
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• 2003

고감도 능동픽셀센서(active pixel sensor, APS)를 위한 PMOSFET 광검출기를 설계 및 제작하였다. 이 센서는 5V의 전원 전압을 사용하며, 1-poly 2-metal $1.5{\mu}m$ CMOS공정으로 제작하였다. 사용된 광검출기는 빛에 대한 감도를 높이기 위해서 n-well과 게이트를 연결한 PHOSFET을 사용하였다. 제작된 광검출기는 일반 MOSFET이 $I_{DS}-V_{DS}$ 곡선과 유사한 특성을 가진다. PMOSFET 광검출기를 기본으로 하여 설계된 1차원 이미지 센서는 16개의 픽셀로 구성되어 있으며, 단위 픽셀은 하나의 PMOSFET 광검출기와 4개의 NMOSFET으로 구성되어있다. 단위 픽셀의 크기는 $86{\mu}m{\times}90.5{\mu}m$이며, 개구율은 약 12%이다.

• 한국정보통신학회논문지
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• 제7권5호
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• pp.1019-1025
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• 2003

조선과 자동차 등의 금속 가공분야의 용접산업부분에서는 용접을 하기 위해 여러 종류의 용접선 추적 센서들이 사용되고 있다. 용접선을 검출하는 센서에는 용접모재와 센서의 접촉여부에 따라 접촉식과 비접촉식 센서로 크게 대별할 수 있고, 현 산업전반에서는 대부분 접촉식 센서를 사용하고 있다. 본 논문에서도 접촉식센서의 일종인 스트레인 게이지를 응용하여 센서를 제작하여 용접부위를 얼마나 잘 추적하는지 실험하였다. 실험장치는 스트레인 게이지 센서, 스트레인 게이지 신호의 증폭회로, 삼각파 발생기, MOSFET 파워 드라이버 회로와 DC 모터로 구동되는 X-Y 슬라이더 등으로 구성되어 있다. 용접선의 추적범위는 상하좌우로 동작을 하고 스트레인 게이지의 저항변화가 X-Y 슬라이더에 연결된 DC 모터를 구동시키게 된다. 실험결과 용접부위를 센서가 잘 추적하는 것을 확인할 수 있었고, 실제 산업현장에 있어서 적용가능성에 대해서 알아보았다.

• 센서학회지
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• 제14권1호
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• pp.42-46
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• 2005

It has been known that 1/f noise of MOSFET is generated by superposition of random telelgraph signals (RTS). In this study, jitters and phase noise caused by 1/f noise of MOSFET are analysed with RTS supplied to all of the nodes of the CMOS ring oscillator under investigation. Through the analysis of jitters and jitter ratios with varying values of the amplitude of RTS, it is found that the jitters and the jitter ratios are proportional to the amplitude of RTS. And the analysis of FFT of the output of the ring oscillator reveals that the jitters are closely related to the phase noise of the high order harmonics of the ring oscillator outputs.

• 센서학회지
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• 제27권3호
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• pp.150-155
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• 2018

Three different structures of GaN MOSFETs with trap distributions, trap levels, and densities were simulated, and its results were analyzed. Two of them are Schottky barrier MOSFETs(SB-MOSFETs): one with a p-type GaN body while the other is in the accumulation mode MOSFET with an undoped GaN body and regrown source/drain. The trap levels, distributions and densities were considered based on the measured or calculated properties. For the SB-MOSFET, the interface trap distribution affected the threshold voltage significantly, but had a relatively small influence on the subthreshold swing, while the bulk trap distribution affects the subthreshold swing more.

• 센서학회지
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• 제16권4호
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• pp.313-318
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• 2007

Single-wall carbon nanotube field-effect transistors (SWCNT FETs) of top gate structure were fabricated in a conventional metal-oxide-semiconductor field effect transistor (MOSFET) with gate electrodes above the conduction channel separated from the channel by a thin $SiO_{2}$ layer. The carbon nanotubes (CNTs) directly grown using thin Fe film as catalyst by thermal chemical vapor deposition (CVD). These top gate devices exhibit good electrical characteristics, including steep subthreshold slope and high conductance at low gate voltages. Our experiments show that CNTFETs may be competitive with Si MOSFET for future nanoelectronic applications.

• 센서학회지
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• 제26권4호
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• pp.292-296
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• 2017

It has become ever harder to design reliable circuits with each nanometer technology node under normal operation conditions, a transistor device can be affected by various aging effects resulting in performance degradation and eventually design failure. The reliability (aging) effect has traditionally been the area of process engineers. However, in the future, even the smallest of variations can slow down a transistor's switching speed, and an aging device may not perform adequately at a very low voltage. Because of such dilemmas, the transistor aging is emerging as a circuit designer's problem. Therefore, in this paper, the impact of aging effects on the delay and power dissipation of digital circuits by using nanomneter MOSFET power gating structure has been analyzed.. Based on this analyzed aging models, a reliable digital circuits can be designed.

• 한국전기전자재료학회논문지
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• 제28권6호
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• pp.403-407
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• 2015

Generally, MWCNT, with thermal, chemical and electrical superiority, is manufactured with CVD (chemical vapor deposition). Using MWCNT, it is comonly used as gas sensor of MOS-FET structure. In this study, in order to repeatedly detect gases, the author had to effectively eliminate gases absorbed in a MWCNT sensor. So as to eliminate gases absorbed in a MWCNT sensor, the sensor was applied heat of 423[K], and in order to observe how the applied heat was diffused within the sensor, the author interpreted the diffusion process of heat, using COMSOL interpretation program. In order to interpret the diffusion process of heat, the author progressed modeling with the structure of MWCNT gas sensor in 2-dimension, and defining heat transfer velocity($u={\Delta}T/{\Delta}x$), accorded to governing equation within the sensor, the author proposed heat transfer mechanism.

• 한국정보통신설비학회:학술대회논문집
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• 한국정보통신설비학회 2008년도 정보통신설비 학술대회
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• pp.559-562
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• 2008

In this paper we propose a lock-in detection method for portable sensor systems and demonstrate with the portable detection module that has high sensitivity and robustness against the noise. The simple portable sensor module is manufactured using MCU(Micro Contorl Unit), OPAMP, MOSFET and a pair of infrared sensor. Manufactured sensor module is testified in the noisy environment caused by an external light and an white noise source. Without any type of band pass filters, we recover a signal of 33 $mV_{p-p}$ in 80 $mV_{p-p}$ white noise and get the DR(Dynamic Reserve) of 14 dB.

• 센서학회지
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• 제28권3호
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• pp.152-156
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• 2019

An ultraviolet (UV) image sensor is an extremely important optoelectronic device used in scientific and medical applications because it can detect images that cannot be obtained using visible or infrared image sensors. Because photodetectors and transistors are based on different materials, conventional UV imaging devices, which have a hybrid-type structure, require additional complex processes such as a backside etching of a GaN epi-wafer and a wafer-to-wafer bonding for the fabrication of the image sensors. In this study, we developed a monolithic GaN UV passive pixel sensor (PPS) by integrating a GaN-based Schottky-barrier type transistor and a GaN UV photodetector on a wafer. Both individual devices show good electrical and photoresponse characteristics, and the fabricated UV PPS was successfully operated under UV irradiation conditions with a high on/off extinction ratio of as high as $10^3$. This integration technique of a single pixel sensor will be a breakthrough for the development of GaN-based optoelectronic integrated circuits.