• Journal of the Korean Institute of Telematics and Electronics D
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• v.35D no.5
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• pp.63-68
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• 1998

The absolute pressure sensor using SDB wafer has been fabricated. the structure of the sensor consists of two wheatstone bridges and a diaphragm. One of the two wheatstone bridges is located on the edge of diaphragm, and the other is located on the center of diaphragm. The diaphragm cavity is sealted in vacuum (~10$^{5}$ Torr) to reduce the effect of temperature due to the vapor in the cavity on the sensitivity of pressure sensor. This is the minor method of temperature compensation method. In this experiment the main compensation method is to use the difference of the two bridge offset voltages. The drift of offset voltage with temperature is reduced by using this method so that temperature charcteristics is improved. In this method the temperature effect in the range of 22~100.deg. C was compensated over 80%.

• Journal of Sensor Science and Technology
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• v.31 no.3
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• pp.139-144
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• 2022

Advanced tactile sensors are receiving significant attention in various industries such as extended reality, electronic skin, organic user interfaces, and robotics. The capabilities of advanced tactile sensors require a variety of functions, including position sensing, pressure sensing, and material recognition. Moreover, they should comsume less power and be bio-friendly with human contact. Recently, a tactile sensor based on the triboelectrification effect was developed. Triboelectric tactile sensors have the advantages of wide material availability, simple structure, and low manufacturing cost. Because they generate electricity by contact, they have low power consumption compared to conventional tactile sensors such as capacitive and piezoresistive. Furthermore, they have the ability to recognize the contact material as well as execute position and pressure sensing functions using the triboelectrification effect. The aim of this study is to introduce the progress of research on triboelectrification-based tactile sensors with various functions such as position sensing, pressure sensing and contact material recognition.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.45 no.11
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• pp.63-70
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• 2008

In this paper, a smart sensor system for the MEMS pressure sensor was developed. A compensation algorithm and programmable calibration circuits were presented to eliminate errors caused by temperature drift of piezoresistive pressure sensors in itself. This system consisted of signal conditioning, calibration, temperature detection, microprocessor, and communication parts and these were integrated into a SOC. A RS-232 interface was employed for monitoring and control of a smart sensor system. The area of fabricated IC is $4.38{\times}3.78\;mm^2$ and a $0.35{\mu}m$ high voltage CMOS process was used. Compensation error for temperature drift of 50 KPa pressure sensors was measured into ${\pm}0.48%$ in the range of $-40^{\circ}C{\sim}150^{\circ}C$. Total power consumption was 30.5 mW.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.29 no.1
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• pp.405-410
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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.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.790-793
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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 effect of residual stress induced in piezoresistor on the distribution of resistance change ratio and supposed the feasible position of piezoresistor. The resulting are following; The tensile residual stress in the vicinity of piezoresistor decreased the value of resistance change ratio and could not effect on all the area of diaphragm but local area around the piezoresistor. Also, the piezoresistor in the diaphragm type pressure sensor with boss should fabricate in the edge of boss in order to increase the sensitivity of pressure sensor.

• 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.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.04b
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• pp.134-138
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• 2000

The physical, electrical and piezoresitive characteristics of CrN(chromiun nitride) thin-films on silicon substrates have been investigated for use as strain gauges. The thin-film depositions have been carried out by DC reactive magnetron sputtering in an argon-nitrogen atmosphere(Ar-(5~25 %)$N_2$). The deposited CrN thin-films with thickness of $3500{\AA}$nd annealing conditions($300^{\circ}C$, 48 hr) in Ar-10 % $N_2$ deposition atmosphere have been selected as the ideal piezoresistive material for the strain gauges. Under optimum conditions, the CrN thin-films for the strain gauges is obtained a high electrical resistivity, $\rho=1147.65\;{\mu}{\Omega}cm$, a low temperature coefficient of resistance, TCR=-186 ppm/$^{\circ}C$ and a high temporal stability with a good longitudinal gauge factor, GF=11.17.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.05b
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• pp.135-141
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• 2000

The physical, electrical and piezoresitive characteristics of CrN(chromiun nitride) thin-films on silicon substrates have been investigated for use as strain gauges. The thin-film depositions have been carried out by OC reactive magnetron sputtering in an argon-nitrogen atmosphere(Ar-(5~25 %)$N_2$). The deposited CrN thin-films with thickness of $3500{\AA}$ and annealing conditions($300^{\circ}C$, 48 hr) in Ar-10 % $N_2$ deposition atmosphere have been selected as the ideal piezoresistive material for the strain gauges. Under optimum conditions, the CrN thin-films for the strain gauges is obtained a high electrical resistivity, $\rho=1147.65\;{\mu}{\Omega}cm$, a low temperature coefficient of resistance, TCR=-186 ppm/$^{\circ}C$ and a high temporal stability with a good longitudinal gauge factor, GF=11.17.

• Journal of the Semiconductor & Display Technology
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• v.14 no.2
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• pp.23-27
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• 2015

In this paper, eco-friendly paper strain gauge was fabricated in the way of printing strain gauge on paper substrate, using PEDOT:PSS ink and inkjet printer technology. As a p-type conductive high polymer, PEDOT:PSS is known to be piezoresistive effect. I formed a strain gauge by connecting in parallel 5 lines of $60{\mu}m$ width printed with PEDOT:PSS. To minimize surrounding influence such as temperature, I formed wheat-stone bridge by combining 4 strain gauges (quarter-bridge strain gauge) which were made up of PEDOT:PSS 5 lines and measured. In quarter-bridge strain gauge, only two strain gauges, facing each other, arranged in strain and horizontal direction were deformed while the other two strain gauge of vertical direction were not. Therefore, quarter-bridge strain gauge showed the output of half bridge. The fabricated quarter-bridge strain gauge had output sensitivity of $105.6{\mu}V/V{\cdot}mm$ and its output linearity was relatively good.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.1229-1230
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• 2015

Monitoring of mechanical properties of tissues as well as direction/quantities of forces is considered as an essential way for disease diagnosis and haptic feedback systems. There are extensively increasing interests for measuring normal/shear force and touch feelings, especially for surgery systems. Highly sensitive and flexible tactile sensor is needed in palpation for detecting cancer cyst as well as real time pressure monitoring in minimally invasive surgery (MIS). Importantly, MEMS technique with miniaturized fabrication technique is essential for the on-chip integration with biopsy and biomedical grasper. Here, we propose the flexible tactile sensor with high sensitivity based on piezoresistive effect. We analyzed the sensitivity according to the pressure and directions and showed the ability of discrimination of the different materials surfaces, illustrating the feasibility of the flexible tactile sensor for biomedical grasper by mimicking human skin.