• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.14 no.12
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• pp.987-993
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• 2001

In this paper, we presents the construction details and output characteristics of a thick film piezoresistive strain gage. The thick film was printed on the ceramic diaphragm back side by screen printing and cured at 850$^{\circ}C$. The strain distribution and deflection on ceramic diaphragm were performed with finite-element method(FEM tool ANSYS-5.3). Various thick film strain gage characteristics were analysed, including nonlinearity, hysteresis, stability and sensitivity of thick film strain gages.

• Proceedings of the KIEE Conference
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• 2000.07c
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• pp.1655-1657
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• 2000

본 논문에서는 세라믹 다이어프램식 압력센서를 설계하기 전에 세라믹 다이어프램의 변위에 대한 최적 조건을 확립하기 위해 세라믹의 기계적 특성, 다이어프램의 두께와 직경 등을 변화시키면서 중심부와 변곡점 부근에서 압력에 대한 다이어프램의 변위를 시뮬레이션 하였다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07b
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• pp.884-887
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• 2003

Strain gages were widely used transducers. Essentially a strain gage was an electric element to which an appropriate type was attached. Strain was sensed by gages and provided electrical output proportional to applied forced. This paper describes the recent development of a thick film strain gage ceramic pressure sensors. The thick film resistors as strain gage in the Wheatstone bridge were fabricated with a novel mixture of ruthenium. The thick-film technology of resistors were printed on the ceramic diaphragm back side by screen printing and cured at $850^{\circ}C$. The mechanical measurements were performed with the computer simulation results(ANSYS 5.1). The output sensitivity was 1.2mV/V, of which max. nonlinearity was less than 0.29%, hysteresis was less than 0.38%FS.

• Proceedings of the Korean Ceranic Society Conference
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• 2003.04a
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• pp.137.1-137
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• 2003

• Proceedings of the Korean Ceranic Society Conference
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• 2003.10a
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• pp.239.2-239
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• 2003

• Journal of Sensor Science and Technology
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• v.24 no.3
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• pp.208-213
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• 2015

The purpose of this study is to optimize the design of a capacitive pressure sensor element using the simulation of electrical characteristics. The simulation of the ceramic sensor diaphragm ($Al_2O_3$) was performed by permitting pressure to change the curvature of the diaphragm. The pressure capacitance ($C_P$) was increased from 19.63 pF to 15.26 pF by applying pressure because the distance between the electrodes has been changed from $30{\mu}m$ to $15{\mu}m$. When the thickness of the diaphragm was changed to 0.46~0.52 mm, a larger capacitance change showed in accordance with the reduced thickness, which means an increase of sensitivity. However, considering the viewpoint of the signal linearity, it was selected for the optimum thickness of the diaphragm to 0.50 mm. The designed sensor element based on simulated results was tested to measure the output characteristics. Comparing of simulated and measured results, there was a margin of error of approximately 2%.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.16 no.9
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• pp.790-794
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• 2003

This paper describes the fabrication and characteristics of ceramic thin film type pressure sensors based on Ta-N strain gauges for high temperature applications. Ta-N thin-film strain gauges are deposited onto a thermally oxidized Si diaphragm by RF sputtering in an argon-nitrogen atmos[here($N_2$ gas ratio: 8%, annealing condition: 90$0^{\circ}C$, 1 hr.), patterned on a wheatstone bridge configuration, and used as pressure sensing elements with a high stability and a high gauge factor. The sensitivity is 1.097 ～ 1.21 mV/Vㆍkgf/$\textrm{cm}^2$ in the temperature range of 25 ～ 200 $^{\circ}C$ and the maximum non-linearity resistance), non-linearity than existing Si piezoresistive pressure sensors. The fabricated ceramic thin-film type pressure sensor is expected to be usefully applied as pressure and load sensors that os operable under high-temperature.

• Journal of Sensor Science and Technology
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• v.12 no.6
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• pp.265-272
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• 2003

This paper describes anodic bonding characteristics of MLCA (Multi Layer Ceramic Actuator) to Si-wafer using evaporated Pyrex #7740 glass thin-films for MEMS applications. Pyrex #7740 glass thin-films with same properties were deposited on MLCA under optimum RF magneto conditions(Ar 100%, input power $1\;W/cm^2$). After annealing in $450^{\circ}C$ for 1 hr, the anodic bonding of MLCA and Si-wafer was successfully performed at 600 V, $400^{\circ}C$ in - 760 mmHg. Then, the MLCA/Si bonded interface and fabricated Si diaphragm deflection characteristics were analyzed through the actuation test. It is possible to control with accurate deflection of Si diaphragm according to its geometries and its maximum non-linearity is 0.05-0.08 %FS. Moreover, any damages or separation of MLCA/Si bonded interfaces do not occur during actuation test. Therefore, it is expected that anodic bonding technology of MLCA/Si wafers could be usefully applied for the fabrication process of high-performance piezoelectric MEMS devices.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07a
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• pp.160-163
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• 2003

This paper describes on anodic bonding characteristics of MLCA(Multi Layer Ceramic Actuator) to Si-wafer using evaporated Pyrex #7740 glass thin-films for MEMS applications. Pyrex #7740 glass thin-films with same properties were deposited on MLCA under optimum RF magneto conditions(Ar 100 %, input power $1\;/cm^2$). After annealing in $450^{\circ}C$ for 1 hr, the anodic bonding of MLCA to Si-wafer was successfully performed at 600 V, $400^{\circ}C$ in - 760 mmHg. Then, the MLCA/Si bonded interface and fabricated Si diaphragm deflection characteristics were analyzed through the actuation test. It is possible to control with accurate deflection of Si diaphragm according to its geometries and its maximum non-linearity is 0.05-008 %FS. Moreover, any damages or separation of MICA/Si bonded interfaces do not occur during actuation test. Therefore, it is expected that anodic bonding technology of MICA/Si wafers could be usefully applied for the fabrication process of high-performance piezoelectric MEMS devices.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.32 no.3
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• pp.207-212
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• 2019

A flat-type piezoelectric ceramic ultrasonic transmitter was successfully fabricated for application in acoustic devices with cone-free diaphragms. The transmitter, possessing a center frequency of 40.6 kHz, exhibited a higher displacement characteristic for a multilayer type compared with a single layer type. Surface roughness treatment of an Al elastic diaphragm influenced a slight increase (1.1 dB) in the sound pressure level (SPL) at $10V_{rms}$ due to the enlarged surface area. The fabricated multilayer piezoelectric ceramic ultrasonic transmitter showed increasing SPL with increasing input voltage, with a maximum SPL of approximately 123.6 dB at $10V_{rms}$. This implies a doubly increased SPL density of $3.6dB/mm^3$, superior to that of a commercial open-type transmitter with a cone.