• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 하계학술대회 논문집
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• pp.561-564
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• 2000

Silicon capacitive pressure sensor has been fabricated by using electrochemical etching stop and silicon-to-glass electrostatic bonding technique. A diaphragm structure is designed to compensate the nonlinear response. A cavity is etched into the silicon to the depth of 2$\mu\textrm{m}$ by anisotropic etching in 20wt.% TMAH solution at 80$^{\circ}C$. A fabricated sensor showed 3.3 pF zero-pressure capacitance, 297 pp.m/mmHg sensitivity, and a 7.4 7%F.S. nonlinear response in a 0-1 kgf/cm$^2$pressure range.

• 한국전기전자재료학회논문지
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• 제23권4호
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• pp.317-322
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• 2010

This paper reports the fabrication and characterization of surface micromachined poly 3C-SiC capacitive pressure sensors on silicon wafer operable in touch mode and normal mode for high temperature applications. FEM(finite elements method) simulation has been performed to verify the analytical mode. The sensing capacitor of the capacitive pressure sensor is composed of the upper metal and the poly 3C-SiC layer. Measurements have been performed in a temperature range from $25^{\circ}C$ to $500^{\circ}C$. Fabrication process of designed poly 3C-SiC touch mode capacitive pressure sensor was optimized and would be applicable to capacitive pressure sensors that are required high precision and sensitivity at high pressure and temperature.

• Journal of Mechanical Science and Technology
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• 제20권4호
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• pp.505-512
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• 2006

This paper presents an integrated multifunctional sensor based on MEMS technology, which can be used or embedded in mobile devices for environmental monitoring. An absolute pressure sensor, a temperature sensor and a humidity sensor are integrated in one silicon chip of which the size is $5mm\times5mm$. The pressure sensor uses a bulk-micromachined diaphragm structure with the piezoresistors. For temperature sensing, a silicon temperature sensor based on the spreading-resistance principle is designed and fabricated. The humidity sensor is a capacitive humidity sensor which has the polyimide film and interdigitated capacitance electrodes. The different piezoresistive orientation is used for the pressure and temperature sensor to avoid the interference between sensors. Each sensor shows good sensor characteristics except for the humidity sensor. However, the linearity and hysteresis of the humidity sensor can be improved by selecting the proper polymer materials and structures.

• 전자공학회논문지A
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• 제30A권7호
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• pp.82-88
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• 1993

This paper describes fabrication of relative type capacitive pressure sensor to be in great demand for many fields. The fabricated sensor consists of two parts` a sensing diaphragm and a pyrox glass cover. The sensor size is 4.5${\times}3.4mm$^{2})$ and 400$\mu$m thick. To improve the nonlinearity, this sensor is designed a rectangular silicon diaphragm with a center boss structure, and in order to improve the temperature characteristics of the sensor in a packaging process, the sensing element is mounted on the pyrex glass support. Some suggestions toward the design and fabrication of improved sensors have been presented. The zero pressure capacitance, Co of sensor is 26.57pF, and the change of capacitance, ${\Delta}$C is 1.55pF from 0Kgf/Cm$^{2}$ to 1Kgf/Cm$^{2}$ at room temperature. The nonlinearity of the sensor output with center boss diaphragm is 1.29%F.S., and thermal zero shift and thermal sensitivity shift is less than 1.43%F.S./$^{\circ}C$and 0.14% F.S./$^{\circ}C$, respectively.

• 센서학회지
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• 제2권1호
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• pp.19-27
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• 1993

본 논문은 $n^{+}$ 에피택셜층을 이용한 전기화학 에칭스톱과 글라스-실리콘의 양극 접합기술을 이용하여 저 압력측정을 위한 용량형 압력센서를 제작한 것이다. 제작된 센서는 하이브리드형으로 센서 커패시터와 기준 커패시터를 갖는 센서 칩과 두가지 출력검출회로 칩으로 구성되어 있다. 이 제작된 센서는 다이아프램 크기가 $1.0{\times}1.0 mm^{2}$이고, 두께가 $10{\mu}m$로 제작된 센서는 압력이 인가되지 않을 때 용량의 크기가 7.1 pF이고, 10 KPa 압력에서 감도가 5.2 %F.S.이다. 또 용량을 전압으로 검출하는 컨버터회로를 이용할 경우, $5{\sim}45^{\circ}C$ 온도범위에서 영점 온도특성과 감도 온도특성은 각각 0.051 %F.S./$^{\circ}C$와 0.12 %F.S./$^{\circ}C$ 이다.

• Transactions on Electrical and Electronic Materials
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• 제7권4호
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• pp.184-188
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• 2006

This work describes efforts in the fabrication and testing of robust microelectromechanical systems (MEMS). Robustness is typically achieved by investigating non-silicon substrates and materials for MEMS fabrication. Some of the traditional MEMS fabrication techniques are applicable to robust MEMS, while other techniques are drawn from other technology areas, such as electronic packaging. The fabrication technologies appropriate for robust MEMS are illustrated through laminated polymer membrane based pressure sensor arrays. Each array uses a stainless steel substrate, a laminated polymer film as a suspended movable plate, and a fixed, surface micromachined back electrode of electroplated nickel. Over an applied pressure range from 0 to 34 kPa, the net capacitance change was approximately 0.14 pF. An important attribute of this design is that only the steel substrate and the pressure sensor inlet is exposed to the flow; i.e., the sensor is self-packaged.

• Journal of Mechanical Science and Technology
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• 제20권4호
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• pp.554-560
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• 2006

This paper describes the demonstration of successful fabrication and initial characterization of micromachined pressure sensors and micromachined jets (microjets) fabricated for use in macro flow control and other applications. In this work, the microfabrication technology was investigated to create a micromachined fluidic control system with a goal of application in practical fluids problems, such as UAV (Unmanned Aerial Vehicle)-scale aerodynamic control. Approaches of this work include: (1) the development of suitable micromachined synthetic jets (microjets) as actuators, which obviate the need to physically extend micromachined structures into an external flow; and (2) a non-silicon alternative micromachining fabrication technology based on metallic substrates and lamination (in addition to traditional MEMS technologies) which will allow the realization of larger scale, more robust structures and larger array active areas for fluidic systems. As an initial study, an array of MEMS pressure sensors and an array of MEMS modulators for orifice-based control of microjets have been fabricated, and characterized. Both pressure sensors and modulators have been built using stainless steel as a substrate and a combination of lamination and traditional micromachining processes as fabrication technologies.

• 센서학회지
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• 제10권3호
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• pp.173-179
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• 2001

현재 사용되어지는 반도체형 압력센서에는 압저항형과 용량형이 있다. 특히 반도체 마이크로 압력센서는 크기도 작고 신호처리회로를 동일칩 위에 집적화 할 수 있어 많은 관심을 모아왔다. 그러나 이러한 형태의 센서들은 제조공정이 복잡해서 생산성이 낮다. 기존의 센서들이 가지는 단점들을 극복하기 위해 새로운 형태의 FET형 압력센서(PSFET : pressure sensitive field effect transistor)를 제안하고 그 동작특성을 조사하였다. 압력 감지 물질은 PZT(Pb(Zr,Ti)$O_3$)를 사용하였다. RF 마그네트론 스퍼터링법을 사용하여 MOSFET의 게이트 절연막 위에 PZT 압전 박막을 증착하였다. PZT의 안정적 상태인 perovskite 구조를 형성하기 위하여 PbO 분위기에서 열처리하는 기법을 도입하였다. 제작된 PSFET의 감도는 0.38 mV/mmHg이다.

• JSTS:Journal of Semiconductor Technology and Science
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• 제14권6호
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• pp.733-740
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• 2014

A resistive micro Pirani gauge using amorphous silicon (a-Si) thin membrane is proposed. The proposed Pirani gauge can be easily integrated with the other process-compatible membrane-type sensors, and can be applicable for in-situ vacuum monitoring inside the vacuum package without an additional process. The vacuum level is measured by the resistance changes of the membrane using the low noise correlated double sampling (CDS) capacitive trans-impedance amplifier (CTIA). The measured vacuum range of the Pirani gauge is 0.1 to 10 Torr. The sensitivity and non-linearity are measured to be 78 mV / Torr and 0.5% in the pressure range of 0.1 to 10 Torr. The output noise level is measured to be $268{\mu}V_{rms}$ in 0.5 Hz to 50 Hz, which is 41.2% smaller than conventional CTIA.

• 센서학회지
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• 제23권5호
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• pp.326-331
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• 2014

In this study, a MEMS microphone that uses $Si_3N_4$ as the vibration membrane was produced for application as an auditory device using a sound visualization technique (sound visualization) for the hearing impaired. Two sheets of 6-inch silicon wafer were each fabricated into a vibration membrane and back plate, after which, wafer bonding was performed. A certain amount of charge was created between the bonded vibration membrane and the back plate electrodes, and a MEMS microphone that functioned through the capacitive method that uses change in such charge was fabricated. In order to evaluate the characteristics of the prepared MEMS microphone, the frequency flatness, frequency response, properties of phase between samples, and directivity according to the direction of sound source were analyzed. The MEMS microphone showed excellent flatness per frequency in the audio frequency (100 Hz-10 kHz) and a high response of at least -42 dB (sound pressure level). Further, a stable differential phase between the samples of within -3 dB was observed between 100 Hz-6 kHz. In particular, excellent omnidirectional properties were demonstrated in the frequency range of 125 Hz-4 kHz.