• Journal of the Microelectronics and Packaging Society
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• v.20 no.4
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• pp.35-39
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• 2013

A four point bending apparatus has been developed to measure semiconductor sensor piezoresistance inside a four inch probe station. The apparatus has a footprint of $60{\times}83mm^2$ and can apply $10{\mu}m$ displacements using a vertical micrometer stage. We used finite element analysis to predict and improve the accuracy of the instrument. Finally strain gauge attached on a silicon test piece was used to experimentally verify the setup.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.186-189
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• 2004

Sensor used by semiconductor process produced an MAP sensor and applied to several industry. Among those sensors divided as transducer which convert physical quantity into electrical value, piezoresistive type sensor has been studied for the properties and sensitivity of piezoresistor. In this paper, the variation of seismic mass which have been functioned as actuator moving the cantilever beam analyzed the effect on distribution of resistance change ratio and supposed the optimal shape and position of piezoresistor. The resulting are following; According to the increment of seismic mass size, the value of resistance change ratio decreased caused by improve the stiffness. Y directional piezoresistor is formed in spot of 100 m apart from cantilever edge and length of that is 800$\mu$m. To increase the sensitivity, piezoresistor is made as n-type and x-direction.

• Journal of the Korean Institute of Telematics and Electronics
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• v.25 no.3
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• pp.307-314
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• 1988

The thin, square-diaphragm silicon pressure sensor utilizing shear piezoresistance effect was designed and fabricated and its characteristics were examined. The sensor has only one diffused resistor, whereas conventional full-bridge sensor has four. Sensitivity is somewhat lower but temperature compensation is easier than the latter. The proposed sensor was fabricated with only one p-type diffused resistor of the dimension of 113x85\ulcorner\ulcornerlocated near the center of the edge of the diaphragm. The resistor was at 45\ulcornerwith the edge of the diaphragm. The sensitivity of the sensor was 36\ulcorner/V\ulcornermHg and was linear in the pressure range from 0 to 300 mmHg. The temperature coefficient without temperature compensation was 55 ppm/\ulcorner and it was decreased to about 0.17 mmHg/\ulcorner with compensation in the range from 10 to 60\ulcorner.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.1381-1384
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• 2005

In these days, the piezoresistive material has been applied to various sensors in order to measure the change of physical quantities. But the relationship between the sensitivity of a sensor and the position and size of piezoresistor has rarely been studied. Therefore, this paper was focused on the distribution of the resistance change ratio on the diaphragm and bridge surface where piezoresistor would be formed, and proposed the proper size and position of piezoresistor with which the sensitivity of sensor was increased. As the width of mass and boss was increased, the distance between piezoresistors was closed and the maximum value of resistance change ratio was decreased by the increase of the structure stiffness. And according to the increment of seismic mass size, the value of resistance change ratio is decreased by increase of the structure stiffness. Y directional piezoresistor is formed in the position of $100\mu{m}\;apart\;from\;cantilever\;edge\;and\;length\;of\;that\;is\;800\mu{m}$.

• Journal of the Korean Institute of Telematics and Electronics
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• v.23 no.3
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• pp.364-369
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• 1986

Silicon diaphragms, 10 and 20 \ulcorner-thick and 1x1 mm\ulcornerarea, have been fabricated by means of the electrochemical P-N junction etch-stop technique. The P-type diffused resistors were formed on the diaphragm, and the piezoresistance effect was examined. It was been found that the fractional variation of the resistance is dependent on the diaphragm thickness, resistor location, and resistor length, etc. The 1.2 k\ulcornerfull-brige pressure sensor with 10\ulcorner-thick diaphragm exhibits a pressure sensitivity of 42 \ulcorner/V\ulcornermHg with a temperature coefficient of 2.3 mmHg/\ulcorner, and shows a good linearity in the pressure range from 0 to 300 mmHg.

• Journal of IKEEE
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• v.1 no.1 s.1
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• pp.1-10
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• 1997

It is well-known that rectangular bulk-Si sensors prepared by etch or epi etch-stop micromachining technology are already in practical use today, but the conventional bulk-Si sensor shows some drawbacks such as large chip size and limited applications as silicon sensor device is to be miniaturized. We consider a circular-shape SOI(Silicon-On-Insulator) micro-cavity technology to facilitate multiple sensors on very small chip, to make device easier to package than conventional sensor like pressure sensor and to provide very high over-pressure capability. This paper demonstrates the cross-functional results for stress analyses(targeting $5{\mu}m$ deflection and 100MPa stress as maximum at various applicable pressure ranges), for finding permissible diaphragm dimension by output sensitivity, and piezoresistive sensor theory from two-type SOI structures where the double SOI structure shows the most feasible deflection and small stress at various ambient pressures. Those results can be compared with the ones of circular-shape bulk-Si based sensor$^{[17]}. The SOI micro-cavity formed the sensors is promising to integrate with calibration, gain stage and controller unit plus high current/high voltage CMOS drivers onto monolithic chip.

• Journal of Sensor Science and Technology
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• v.5 no.5
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• pp.31-37
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• 1996

This paper presents characteristics of pressure sensor using shear-type piezoresistor of LPCVD(low pressure chemical vapour deposition) grown polycrystalline silicon films. The sensor has 3.1mV/V of pressure sensitivity in the pressure range of $1kgf/cm^{2}$, ${\pm}0.012%FS/^{\circ}C$ of TCO, and ${\pm}0.08%FS/^{\circ}C$ of TCS in the temperature range of $-20{\sim}+125^{\circ}C$. It showed ${\pm}0.2%FS$ of hysteresis and ${\pm}1.5%FS$ of non-linearity. Shear-type polycrystalline silicon pressure sensor can eliminate temperature dependence of offset caused by resistors mismatch and be used in relatively wide temperature range, compared to the conventional full-bridge silicon pressure sensors.

• Journal of the Korean Society of Propulsion Engineers
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• v.22 no.6
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• pp.111-117
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• 2018

In this study, an MEMS thrust measurement system was designed and a study on the performance prediction of system was performed to evaluate the performance of micro thruster. Thrust measurement system consists of beam, membrane, and piezoresistive sensor. An FEM analysis was carried out to verify the stability of the system, confirm the stress variation at the beam, and position the piezoresistive sensor. The stability of the designed system was verified by comparing the yield strength of the material with the maximum stress. The piezoresistive sensor was designed to be 20% of the length of the beam to obtain a high gauge factor. The size of the membrane and the beam of the reference model were designed to be $15mm{\times}15mm$, and $500{\mu}m{\times}500{\mu}m$, respectively.