• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.22 no.4
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• pp.303-306
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• 2009

This paper describes the characteristics of polycrystalline 3C-SiC doubly clamped beam micro resonators. The polycrystalline 3C-SiC doubly clamped beam resonators with $60{\sim}100{\mu}m$ lengths, $10{\mu}m$ width, and $0.4{\mu}m$ thickness were fabricated using a surface micromachining technique. Polycrystalline 3C-SiC micro resonators were actuated by piezoelectric element and their fundamental resonant frequency was measured by a laser vibrometer in vacuum at room temperature. For the $60{\sim}100{\mu}m$ long cantilevers, the fundamental frequency appeared at $373.4{\sim}908.1\;kHz$. The resonant frequencies of doubly clamped beam with lengths were higher than simulated results because of tensile stress. Therefore, polycrystalline 3C-SiC doubly clamped beam micro resonators are suitable for RF MEMS devices and bio/chemical sensor applications.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.250-250
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• 2008

This paper describes the resonant characteristics of polycrystalline SiC micro resonators. The $1{\mu}m$ thick polycrystalline 3C-SiC cantilevers with different lengths were fabricated using a surface micromachining technique. Polycrystalline 3C-SiC micro resonators were actuated by piezoelectric element and their fundamental resonance was measured by a laser vibrometer in vacuum at room temperature. For the 100 ~ $40{\mu}m$ long cantilevers, the fundamental frequency appeared at 147.2 kHz - 856.3 kHz. The $100{\mu}m$ and $80{\mu}m$ long cantilevers have second mode resonant frequency at 857.5 kHz and 1.14 MHz. Therefore, polycrystalline 3C-SiC micro resonators are suitable for RF MEMS devices and bio/chemical sensor applications.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.35D no.4
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• pp.78-83
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• 1998

A small size cartrideg for FET type electrolyte sensor is designed and faricated with much simplified process by using micromachining tenchiques such as silicon etching andglass bonding. Size of the whole cartideg is 2.4cm*2.5cm, and the dead volume of a micro flow-channel in the cartrideg is only 8.5.mu.l. The photosensitive polymer(THB 30) is used to define a micropool and to encapsulate the sensor surface for standardizationof electrolyte sensors. To miniaturize micro flow-channel conventional reference electrode(Ag/AgCl) a differential amplification is introduced using REFET and quasi reference electrode. Refet was fabricated using photosensitive polymer(OMR 83). The fabricated cartridge with built-in pH-ISFET showed good operational characteristics such as linearity and high sensitivity (55.4mV/pH) in a wide pH range(pH2-pH12).

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.04a
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• pp.53-57
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• 1996

The side burrs and shape distortion resulting from the micromachining of an array of V-shape microgrooves in optical components were experimentally invesigated and a simplified model for their formation is proposed. Burr/shpae distortion should be kept to a minimum level since they degrade the characteristics and performance of these parts. The focus of this study is on the influence of depth of cut and workpiece material. The workpiece materials use were brass, bronze and copper. From the obsevation of the chip shape and burr/shape distortion, the proposed model, that the compressive force at the cutting edge causess the ductile uncut chip material to flow plastically outward toward the free surface to result in a burr, was verified.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.17 no.6
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• pp.63-70
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• 2008

Conical horn is used in many high frequency ultrasonic horns, to achieve a longitudinal vibration mode across a wide ultrasonic tool horn output surface. Modal analysis is method for designing tuned ultrasonic tool horn and for the prediction natural frequency of ultrasonic tool horn vibration mode. The design of ultrasonic horn is based on prototype estimate obtained by FEM analysis. The FEM simulated ultrasonic tool horn is built and characterized experimentally through laser vibrometer and electrical impedance analysis. In this paper, FEM analysis is developed to predict the natural frequency of ultrasonic tool horn and use of in the optimal design of ultrasonic horn shape.

• Proceedings of the KIEE Conference
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• 1995.11a
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• pp.609-611
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• 1995

In this study, we experimented the properties of SOG film as sacrificials layers in surface micromachining and made $SiO_2$ films through spin, bake, cure process. When we culled SOG films once, SOG film thickness is 1000 $\sim$ 3000 ${\AA}$. Then we coaled 200-${\AA}$ SOG film on 9000 ${\AA}$-CVD oxide and then we fabricated test structure, cantilever and ring/beam structure. We estimated deformed structure by SEM. As the results, The deformation of the structure layer in the SOG-coated sacrificial layers is small compared with that or the structure layer on CVD oxide or PSG. In the future, we use multi coated SOG films, SOG film become adequate material as sacrificial layer.

• Proceedings of the KIEE Conference
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• 1997.11a
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• pp.659-661
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• 1997

An in-plane motion measurement method using $moir{\acute{e}}$ patterns by linear-gratings and cross-gratings, which can be used as micro inertial sensors, micro actuators, and micromachined scanning microscopes is demonstrated. A simple digital image processing method that calculates and analyzes the motion of microstructure from $moir{\acute{e}}$ patterns was developed. And using several grating structures fabricated by surface micromachining, we formed $moir{\acute{e}}$ patterns and analyzed the motion of microstructure.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.12
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• pp.2474-2479
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• 2009

This paper presents an atmospheric microplasma-jet device for bio~medical application. The microplasma-jet device consists of four components; a thin Ni anode, porous alumina insulator, a stainless steel cathode and an aluminum case. The anode has 8 holes, and hole diameter and depth are $200 {\mu}m$ and $60 {\mu}m$, respectively. The discharge test was performed in atmospheric pressure using nitrogen gas and AC voltage at the optimum gas flow rate of 4 Vmin. The plasma-jet is ejected stably for the input voltage ranging from 5.5 to $9.5 kV_{p-p}$. The plasma becomes dense as the input voltage increases, which was verified by the hydrophilicity change of PMMA surface treated by the plasma. The temperature increasement of the aluminum film exposed to plasma-jet illustrates that the micro plasma-jet device is feasible for bio-medical application.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.8
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• pp.1259-1265
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• 2003

We present a new post-fabrication frequency tuning method for laterally driven electrostatic microresonators using a DC-biased electrostatic comb array of linearly varied finger-length. The electrostatic tuning force and the equivalent stiffness, adjusted by the DC-biased tuning-comb array, have been formulated as functions of geometry and DC tuning voltage. A set of frequency-turnable microresonators has been designed and fabricated by 4-mask surface-micromachining process. The resonant frequency of the microfabricated microresonator has been measured for a varying tuning voltage at the reduced pressure of 1 torr. The maximum 3.3% reduction of the resonant frequency is achieved at the tuning voltage increase of 20V.

• Proceedings of the KIEE Conference
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• 2002.07c
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• pp.2023-2025
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• 2002

We have fabricated a novel vertical trench-Hall device sensitive to the magnetic field parallel to the sensor chip surface. The vertical trench-Hall 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 350 V/AT is measured.