• Journal of Sensor Science and Technology
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• v.19 no.3
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• pp.197-201
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• 2010

This paper describes the fabrication and characteristics of a NO sensor using ZnO thin film integrated 3C-SiC micro heater based on polycrystalline 3C-SiC thin film of operation in harsh environments. The sensitivity, response time, and operating properties in high temperature and voltages of NO sensors based SiC MEMS are measured and analyzed. The sensitivity of device with pure ZnO thin film at the heater operating power of 13.5 mW ($300^{\circ}C$) is 0.875 in NO gas concentration of 0.046 ppm. In the case of Pt doping, the sensitivity of at power consumption of 5.9 mW ($250^{\circ}C$) was 1.92 at same gas flow rate. The ZnO with doped Pt was showed higher sensitivity, lower working temperature and faster adsorption characteristics to NO gas than pure ZnO thin film. The NO gas sensor integrated SiC micro heater is more strength than others in high voltage and temperature environments.

• Corrosion Science and Technology
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• v.5 no.3
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• pp.112-116
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• 2006

This study has been conducted to monitor the corrosion rate of cathodically protected structure and corrosion inhibited system using multi-line thin-film electrical resistance (TFER) sensor in various environments. The field test data of TFER sensor for the corrosion monitoring of cathodically protected underground pipeline in soil environments and of corrosion inhibited gas heaters were also presented. The sensor was found to be a powerful method to commit the sensitive pick-up of small corrosion rate which can be observed in the cathodically protected and corrosion inhibited systems.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.07a
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• pp.443-446
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• 2001

MI(Magneto-Impedance) sensor which is made by thin films has significantly high detecting sensitivity in weak magnetic field. It also has a merit to be able to build in low power system. Its structure is simple, which makes it easier to prepare a miniature. In this study, its magnetic permeability and anisotropy field(H$\sub$k/) as a function of a thickness of sputtered amorphous CoZrNb thin film with high saturation magnetostriction and excellent soft magnetic property are investigated. In order to make a uniaxial anisotropy, thin film was subjected to post annealing with a static magnetic field with 1KOe intensity at 250, 300, and 320$^{\circ}C$ for 2 hour. Anisotropy field(H$\sub$k/)of thin film is measured by using MH loop tracer. Its magnetic permeability of thin film is measured over the frequency range from 1 MHz to 750MHz. It has shown that the magnetic permeability of amorphous CoZrNb thin film is decreased due to the skin effect with increasing a thickness of CoZrNb thin film, and hence its driving frequency is lowered.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.957-960
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• 2009

Sensor applications of thin-film transistors (TFTs), such as photosensor, magnetic sensor, temperature sensor and chemical sensor, are introduced. Active-matrix circuits and amplifying circuits using poly-Si TFTs are integrated with these sensors to improve sensor performances and generate additional functions. These sensors may be promising applications after flat-panel displays (FPDs) in giant-micro electronics.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07b
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• pp.888-891
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• 2003

This paper describes on the fabrication and characteristics of micro ceramic thin-film type pressure sensors based on Ta-N strain-gauges for high-temperature applications. The Ta-N thin-film strain-gauges are deposited onto thermally oxidized Si diaphragms by RF sputtering in an argon-nitrogen atmosphere($N_2$ gas ratio: 8 %, annealing condition: $900^{\circ}C$, 1 hr.), Patterned on a wheatstone bridge configuration, and use as pressure sensing elements with a high stability and a high gauge factor. The sensitivity is $1.097{\sim}1.21mV/V.kgf/cm^2$ in the temperature range of $25{\sim}200^{\circ}C$ and the maximum non-linearity is 0.43 %FS. The fabricated pressure sensor presents a lower TCR, non-linearity than existing Si piezoresistive pressure sensors. The fabricated micro ceramic thin-film type pressure sensor is expected to be usefully applied as pressure and load sensors that is operable under high-temperature environments.

• Journal of Sensor Science and Technology
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• v.15 no.5
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• pp.309-316
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• 2006

The $SnO_{2}$ thin film sensors were fabricated by a thermal oxidation method. $SnO_{2}$ thin film sensors were treated in $N_{2}$ atmosphere. The sensors with $O_{2}$ treatment after $N_{2}$ treatment showed 70 % sensitivity for 1 ppm $H_{2}S$ gas, which is higher than the sensors with only $O_{2}$ treatment. The Ni metal was evaporated on Sn thin film on the $Al_{2}O_{3}$ substrate. And the sensor was heated to grow the Sn nanowire in the tube furnace with $N_{2}$ atmosphere. Sn nanowire was thermally oxidized in $O_{2}$ environments. The sensitivity of $SnO_{2}$ nanowire sensor was measured at 500 ppb $H_{2}S$ gas. The selectivity of $SnO_{2}$ nanowire sensor compared with thin film and thick film $SnO_{2}$ was measured for $H_{2}S$, CO, and $NH_{3}$ in this study.

• Journal of Sensor Science and Technology
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• v.26 no.6
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• pp.414-419
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• 2017

The optical characteristics of cresol red, phenol red, and neutral red immobilized in the thin film were investigated with absorbance measurement in order to find a sensing part of a fiber-optic pH sensor. Sol-Gel method with tetramethyl orthosilicate as a precursor was used to immobilize the pH indicators in the thin film. The absorbance spectra were measured when pH indicators were immobilized in the film and were dissolved in the buffer solution. Experimental results showed that the absorbance spectra could be changed when the pH indicator is immobilized in the thin film. As compared with other pH indicators, the neutral red exhibited similar absorbance spectra regardless of physical conditions and was sensitive over whole pH range between 4 and 11. In addition, the absorbance ratio of base peak to acid peak tended to increase in proportion to the increase in pH. Experimental results indicate that the neutral red is a good pH indicator for fabrication of a sensing part of the fiber-optic pH sensor.

• Journal of Sensor Science and Technology
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• v.28 no.2
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• pp.133-138
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• 2019

The a-InGaZnO (a-IGZO) thin film transistor (TFT) has the advantages of larger mobility than that of amorphous silicon TFTs, acceptable reliability and uniformity over a large area, and low process cost. A capacitive-type touch sensor was studied with an a-IGZO TFT that can be used on the front side of a display due to its transparency. A capacitive sensor detects changes of capacitance between the surface of the finger and the sensor electrode. The capacitance varies according to the distance between the sensor plate and the touching or non-touching of the sensing electrode. A capacitive touch sensor using only one a-IGZO TFT was developed with the reduction of two bus lines, which made it easy to reduce the pixel pitch. The proposed sensor circuit maintained the amplification performance, which was investigated for various drive conditions.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.05a
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• pp.192-196
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• 2002

This paper describes on the fabrication and characteristics of a metal thin-film pressure sensor based on Cr strain-gauges for harsh environment applications. The Cr thin-film strain-gauges are sputter-deposited onto a micromachined Si diaphragms with buried cavity for overpressure protectors. The proposed device takes advantages of the good mechanical properties of single-crystalline Si as diaphragms fabricated by SDB and electrochemical etch-stop technology, and in order to extend the operating temperature range, it incorporates relatively the high resistance, stability and gauge factor of Cr thin-films. The fabricated pressure sensor presents a low temperature coefficient of resistance, high-sensitivity, low non-linearity and excellent temperature stability. The sensitivity is 1.097~1.21 $mV/V{\cdot}kgf/cm^2$ in the temperature range of $25{\sim}200^{\circ}C$ and the maximum non-linearity is 0.43 %FS.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.36 no.10
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• pp.719-723
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• 1987

This paper shows the design method and the experimental results of the thin film thickeness monitor. The thin film thickness monitor uses 6 MHz quartz crystal in sensor and cooling system for the fine operation. The thin film thickness are measured by the digital frequrency counter.