• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.354-355
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• 2008

The sensitivity and sensing margin of SOI(silicon on insulator) nano-wire BioFET(field effect transistor) were investigated by using back-gate bias. The channel conductance modulation was affected by doping concentration, channel length and channel width. In order to obtain high sensitivity and large sensing margin, low doping concentration, long channel and narrow width are required. We confirmed that the electrical sensing by back-gate bias is effective method for evaluation and optimization of bio-sensor.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.55 no.5
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• pp.263-266
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• 2006

An optical microphone was developed using a dual-core multi-mode fiber block and a membrane type micromirror. The fiber block serves as a compact optical head, and the micromirror as a reflective diaphragm. The micromirror is designed to be suspended through a silicon bar connected t a frame, allowing for displacement induced by acoustic waves. The optical head is implemented by integrating two multi-mode fibers in a single block, and used to transfer light signals between it and the diaphragm. For the assembled microphone, its static characteristics were observed to reveal the operating point defined as the optimum distance between the optical head and the diaphragm. And its dynamic response was tested to exhibit a frequency bandwidth of 3 kHz with the variation of $\sim5dB$.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.16 no.9
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• pp.838-841
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• 2003

This paper shows results on the application of optical fiber sensors(OFS) for locations of ultrasonic signals in silicon insulating oil. The OFS system based on the principle of Sagnac interferometry has been designed and established for this work. The hollowed cylindrical mandrel wound by single mode optical fiber was used as a sensing component and ultrasonic signals which simulate the partial discharge In the oil have been generated by PZT actuator operated with function generator. The experimental results shows that the OFS has a excellent performance for the PD location with resolutions less than 1$^{\circ}C$ error range in the miniature insulating oil tank.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.19 no.5
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• pp.405-410
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• 2006

We fabricated gas sensors using carbon nanotubes (CNTs) as electron emitters for the purpose of detecting inert gases. By using the silicon-glass anodic bonding and glass patterning technologies with the typical Si process, we improved the compactness of the sensors and the reliability in process. The proposed sensor, based on, an electrical discharge theory known as Paschen's law in principle, works by figuring the variation of the discharge current depending on gas concentration. In the experiment, the initial breakdown characteristics were measured for air and Ar as a function of gas pressure. As the result, even though it should be realized that there are many other factors which have an effect on the breakdown of a gap, the sensors led to similar result as predicted by Paschen's law, and they showed a possibility as gas sensors which enable to detect the gas density ranged to the vacuum pressure from 1 to $10^{-3}$ Torr.

• Proceedings of the KIEE Conference
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• 2000.07c
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• pp.1788-1790
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• 2000

본 논문에서는 마이크로 바이오 센서에 응용하기 위한 기초 실험으로서 다공성 실리콘을 이용한 요소 센서의 특성을 고찰하였다. 센서의 감도나 내구성 측면에서 보면 전도성 고분자를 전기중합(electropolymerization)한 후 효소를 전착(electrodeposition)하여 고정화하는 것보다는 PSi 표면에 효소를 코팅한 후 그 위에 고분자를 전기 중합하는 것이 유리하였다. SEM 이미지와 EDX 스펙트럼 분석 결과로부터 urease와 polypyrrole(PPy)이 다공질 실리콘 표면에 코팅되었음을 알 수 있었으며, 요소 농도가 1mM$\sim$1M 영역(일반적인 혈중 요소 농도는 $20{\mu}M{\sim}30{\mu}M$)에서 감도는 $30{\mu}A/decade$ 였다.

• Transactions on Electrical and Electronic Materials
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• v.10 no.6
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• pp.189-192
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• 2009

The leakage current in a CMOS image sensor (CIS) can have various origins. Leakage current investigations have focused on such things as cobalt-salicide, source and drain scheme, and shallow trench isolation (STI) profile. However, there have been few papers examining the effects on leakage current of nitride stringers that are formed by gate sidewall etching. So this study reports the results of a series of experiments on the effects of a nitride stringer on real display images. Different step heights were fabricated during a STI chemical mechanical polishing process to form different nitride stringer sizes, arsenic and boron were implanted in each fabricated photodiode, and the doping density profiles were analyzed. Electrons that moved onto the silicon surface caused the dark leakage current, which in turn brought up the speckle defect on the display image in the CIS.

• JSTS:Journal of Semiconductor Technology and Science
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• v.15 no.3
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• pp.349-355
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• 2015

A fully-differential touch-screen sensing architecture is presented to improve noise immunity and also support most multi-touch events minimizing the number of amplifiers and their silicon area. A correlated double sampling function is incorporated to reduce DC offset and low-frequency noises, and a stabilizer circuit is also embedded to minimize inherent transient fluctuations. A prototype of the proposed readout circuit was fabricated in a $0.18{\mu}m$ CMOS process and its differential operation in response to various touch events was experimentally verified. With a 3.3 V supply, the current dissipation was 3.4 mA at normal operation and $140{\mu}A$ in standby mode.

• Proceedings of the Materials Research Society of Korea Conference
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• 2009.05a
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• pp.52.1-52.1
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• 2009

Cupric oxide (CuO) is a p-type semiconductor with band gap of ~1.7 eV and reported to be suitable for catalysis, lithium-copper oxide electrochemical cells, and gas sensors applications. The nanoparticles, plates and nanowires of CuO were found sensing to NO2, H2S and CO. In this work, we report about the comparison about hydrogen sensing of nano thin film and nanowires structured CuO deposited on single-walled carbon nanotubes (SWNTs). The thin film and nanowires are synthesized by deposition of Cu on different substrate followed by oxidation process. Nano thin films of CuO are deposited on thermally oxidized silicon substrate, whereas nanowires are synthesized by using a porous thin film of SWNTs as substrate. The hydrogen sensing properties of synthesized materials are investigated. The results showed that nanowires cupric oxide deposited on SWNTs showed higher sensitivity to hydrogen than those of nano thin film CuO did.

• Journal of Sensor Science and Technology
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• v.22 no.5
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• pp.374-378
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• 2013

In this paper, a new structure of probe unit is designed and fabricated with PDMS, which is well-known elastic material, as a buffer layer for increasing overdrive force and mechanical strength. In general, PDMS is widely used as actuation material due to its elasticity and compatibility of fabrication process. In this work, PDMS layer is chosen for mechanical elasticity of the proposed probe unit. We achieved the high overdrive force by placing PDMS buffer layer under the silicon based cantilever due to its elasticity. Moreover, the relation between prove length and overdrive force was measured by experiment in this work. Therefore, the various specifications of the micro prove unit can be designed by using the results of this work.

• Proceedings of the KIEE Conference
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• 2002.11a
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• pp.251-253
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• 2002

We have fabricated a novel Vertical Trench Hall-Effect Device sensitive to the magnetic field parallel to the sensor chip surface for non-contact angular position sensing applications. The Vertical Trench Hall-Effect Device is built on SOI wafer which is produced by silicon direct bonding technology using bulk micromachining, where buried $SiO_2$ layer and surround trench define active device volume. Sensitivity up to 150 V/AT is measured.