• Journal of the Korean Electrochemical Society
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• v.2 no.1
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• pp.17-22
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• 1999

Since the use of porous silicon for microsensors and microactuators is in the euly stage of study, only several application devices, such as light-emitting diodes and chemical sensors have so far been demonstrated. In this paper we present an overview of the present status of porous silicon sensors and actuators research with special emphasis on the applications of chemical sensors and optical devices. The capacitive type porous silicon humidity sensors had a nonlinear capacitance-humidity characteristic and a good sensitivity at higher humidity above $40\%RH$. The porous silicon $n^+-p-n^+$ device showed a sharp increase in current when exposed to an ethanol vapor. The $p^+-PSi-n^+$ diode fabricated on porous silicon diaphragm exhibited an optical switching characteristic, opening up its utility as an optical sensor or switch. The photoluminescence (PL) spectrum, taken from porous silicon under 365 nm excitation, had a broad emission, peaked at -610 nm. The electroluminescence(EL) from ITO/PSi/In LED had a broader spectrum with a blue shifted peak at around 535nm than that of the PL.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.07a
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• pp.451-454
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• 2001

In this study, a micro-glucose sensor was fabricated by micromachining technology and its sensing characteristics were investigated. The 7740 pyrex glass was used as the bottom substrate and anisotropically etched silicon wafer was used as the top substrate. The size of the fabricated microchip is 1.58${\times}$1.58mm$^2$. It is shown that output current exhibits a linear change according to glucose concentration (100 mM ∼ 300 mM). It is also shown that the response time for glucose was within 240 sec. It was followed by a saturation trend within 50 sec. The g1ucose sensor with Fc$\^$+/ exhibits relatively higher sensitivity than that without Fc$\sub$+/ for output current.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.646-646
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• 2013

그래핀은 이차원의 탄소 원자들이 벌집구조를 이루는 탄소 원자 한 층의 물질이다. 우수한 기계적, 전기적, 광학적 특성으로 인해 투명전극, 가스 센서, 트랜지스터 등과 같이 다양한 응용이 가능하고 연구가 행해지고 있다. 최근 몇 년 동안, 그래핀의 우수한 특성을 이용해서 마이크로센서나 신축성 있는 전자소자를 위한 전도막과 같은 응용이 시도되고 있다. 본 연구에서는 화학기상증착법 (CVD)으로 합성한 그래핀을 이용해서 암모니아 가스 센서 소자를 제작, 센서 특성을 관찰하였다. 구리 기판을 이용하여 화학기상증착법으로 그래핀을 합성하였으며 진공로에서 수소(H2)와 메탄(CH4) 가스를 사용하였다. 그래핀 합성 온도, 가스 유량 등을 변화시키며 그래핀을 합성하고, 합성된 그래핀을 구리기판을 식각용액을 이용해 제거하는 방법으로 그래핀을 전사시키는 공정거쳐 Au/Ni 전극패턴 위에 전사시킴으로 가스 센서 소자를 제작하였다. 제작된 센서 소자를 이용해 상온에서 암모니아(NH3) 가스의 유량을 변화시키며 실험하였다. 암모니아 가스가 흐를 때 그래핀에 암모니아 분자가 흡착되어 그래핀의 전기저항을 증가시켜 이를 이용해서 암모니아 가스를 감지할 수 있었다. 본 연구에서 제작한 소자는 상온에서 암모니아 가스에 민감하게 반응했으며 이는 기존의 금속산화물을 이용한 암모니아 센서는 대부분 고온에서 작동하는 점과 비교 하였을 때 가스 센서 소자로써 큰 장점이라고 할 수 있다.

• Journal of the Microelectronics and Packaging Society
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• v.29 no.3
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• pp.1-12
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• 2022

With the rapid development of artificial intelligence technology that gives existing sensors functions similar to human intelligence is drawing attention. Previously, researches were mainly focused on an improvement of fundamental performance indicators as sensors. However, recently, attempts to combine artificial intelligence such as classification and prediction with sensors have been explored. Based on this, intelligent sensor research has been actively reported in almost all kinds of sensing fields such as disease detection, motion detection, and gas sensor. In this paper, we introduce the basic concepts, types, and driving mechanisms of artificial intelligence and review some examples of its use.

• Journal of the Korean Magnetics Society
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• v.17 no.3
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• pp.141-146
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• 2007

A new class of LC-resonator for micro magnetic sensor device was invented and fabricated by means of MEMS technique. The micro LC-resonator consists of a solenoidal micro-inductor with a bundle of soft magnetic microwire cores and a capacitor connected in parallel to the micro-inductor. The core magnetic material is a tiny glass coated $Co_{83.2}B_{3.3}Si_{5.9}Mn_{7.6}$ microwire fabricated by a glasscoated melt spinning technique. The core materials were annealed at various temperatures $150^{\circ}C,\;200^{\circ}C\;,250^{\circ}C\;,$ and $300^{\circ}C$ for 1 hour in a vacuum to improve soft magnetic properties. The solenoidal micro-inductors fabricated by MEMS technique were $500{\sim}1,000{\mu}m$ in length with $10{\sim}20$ turns. The changes of inductance as a function of external magnetic field in micro-inductors with properly annealed microwire cores were varied as much as 370%. Since the permeability of ultra soft magnetic microwire is changing rapidly as a function of external magnetic field. The inductance ratio as well as magnetoimpedance ratio (MIR) in a LC-resonator was varied drastically as a function of external magnetic field. The MIR curves can be tuned very precisely to obtain maximum sensitivity. A prototype magnetic sensor device consisting of the developed microinductors with a multivibrator circuit was test successfully.

• Proceedings of the KIEE Conference
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• 2004.07c
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• pp.2117-2120
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• 2004

본 논문은 UV-LIGA 공정, 후막공정을 이용한 바이오센서용 magnetic bead 분리 장치의 제작 기술개발에 관한 것이다. 최근 MEMS(microelectromechanical system) 기술을 이용한 바이오센서에 대한 연구가 활발하게 이루어지고 있다. 이러한 바이오센서 분야 중 혈액이나 다른 원하지 않는 물질을 분리해 주는 분리장치는 MEMS 기술을 이용해 구현이 매우 어려운 부분 중에 하나이다. 기존의 UV-LIGA 공정과 도금법을 이용한 마이크로 전자석 제작하여 분리장치를 제작하는 경우 제작 공정이 매우 복잡하며 매우 많은 공정비용을 요구한다. 이러한 단점을 해결하기 위해 본 논문에서는 Sr 계연의 고분자 자석과 3차원 PDMS(poly-dimethylsiloxane) 마이크로 채널 공정을 이용해 분리장치를 제작하였다. 제작된 분리장치는 $0{\sim}30{\mu}{\ell}$/min 의 속도에서 유체를 흘렸을 90% 이상의 분리 효율을 나타냈다. 개발된 분리 장치는 연재질의 PDMS 로 제작되어 일회용 바이오센서에 적용이 가능하다.

• Proceedings of the KIEE Conference
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• 2000.07c
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• pp.2251-2253
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• 2000

MEMS기술을 이용하여 단층 실리콘 나이트라이드($Si_{3}N_4$) 다이아프램을 제조하고, 이 다이아프램상에 저항성 가열 진공증착법과 고주파 마그네트론 스퍼터링법을 이용하여 차례로 In막과 ZnO막을 증착하고, In의 도핑을 위해 열처리하여 $NH_3$ 가스 감지용 마이크로센서를 제작하였다. 감지막의 열처리온도에 따른 구조적 및 전기적 특성은 XRD, SEM, AFM, 4-point probe 및 Electrometer를 통하여 각각 조사하였다. 제작된 센서의 열처리온도와 인가전력에 따라 $NH_3$ 가스에 대한 감도, 선택성 및 시간응답 특성을 조사하였다. 감지막 두께 3000 ${\AA}$, 열처리온도 400$^{\circ}C$로 제조된 마이크로 센서가 히터 인가전력 366 mW에서 100 ppm의 $NH_3$ 가스농도에서 대하여 16 %, 350 ppm의 가스농도에서 대하여 23 %의 가장 우수한 감도를 나타내었다. 그러나 CO 가스 및 $NO_x$ 가스에 대한 감지특성은 관찰되지 않았다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2014.05a
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• pp.850-852
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• 2014

Recently, the development of Machine to Machine (M2M) communication has been largely accomplished in a variety of fields including smart home. In M2M communication, the role of sensor node is only limited to gather data and send them to upper application layers. In this research, the limited role of the sensor node in traditional M2M communication is improved in order for the devices to make inference, which makes it possible to provide basic context-aware services within sensor node level. Therefore, implementation of rule-based inference system on microcontroller for smart home is proposed.

• The Journal of the Convergence on Culture Technology
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• v.8 no.2
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• pp.355-360
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• 2022

In this paper, we present design and developing method for EMS(environment monitoring system) of micro data center. This developing EMS monitors operating environment of micro data center and analyze sensing data through IoT(Internet of things) sensors in real time. Firstly we present configuration method of IoT sensing package and design method EMS hardware platform. Secondly we design data collector software for data collection of IoT sensor with different protocol and develop monitoring software of EMS. The data collector software consists of sensor collector module and collector manager module. Also we design EMS software which has micro service architecture structural style and component based business logic.

• Journal of the Korean Society for Nondestructive Testing
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• v.31 no.5
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• pp.487-493
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• 2011

Alpha fetoprotein(AFP), which is serological marker for hepatocellular carcinoma, was quantitatively measured by its normal concentration, 10 ng/ml, with a label-free piezoelectric microcantilever mass sensor. The principle of detection is based on changes in the resonant frequency of the piezoelectric microcantilever before and after target molecules are attached to it, and its resonant frequency is measured electrically using a conductance spectrum. The resonant frequency of the developed sensor is approximately 1.34 MHz and the mass sensitivity is approximately 175 Hz/pg. The sensor has high reliability as mass sensor by reducing the effect of surface stress on resonant frequency due to attached proteins. 'Dip and dry' technique was used to react the sensor with reagents for immobilizing AFP antibody on the sensor and detecting AFP antigen. The measured mass of the detected AFP antigen was 6.02 pg at the concentration of 10 ng/ml, and 10.67 pg at 50 ng/ml when the immunoreaction time was 10 min.