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Journal Article
Surface Micromachined Pressure Sensor with Substrate Internal Vacuum Cavity
- Authors
- Chang Han Je, Chang Auck Choi, Sung Q Lee, Woo Seok Yang
- Issue Date
- 2016-08
- Citation
- ETRI Journal, v.38, no.4, pp.685-694
- ISSN
- 1225-6463
- Publisher
- 한국전자통신연구원 (ETRI)
- Language
- English
- Type
- Journal Article
- Abstract
- A surface micromachined piezoresistive pressure sensor with a novel internal substrate vacuum cavity was developed. The proposed internal substrate vacuum cavity is formed by selectively etching the silicon substrate under the sensing diaphragm. For the proposed cavity, a new fabrication process including a cavity side-wall formation, dry isotropic cavity etching, and cavity vacuum sealing was developed that is fully CMOS-compatible, low in cost, and reliable. The sensitivity of the fabricated pressure sensors is 2.80 mV/V/bar and 3.46 mV/V/bar for a rectangular and circular diaphragm, respectively, and the linearity is 0.39% and 0.16% for these two diaphragms. The temperature coefficient of the resistances of the polysilicon piezoresistor is 0.003% to 0.005% per degree of Celsius according to the sensor design. The temperature coefficient of the offset voltage at 1 atm is 0.0019 mV and 0.0051 mV per degree of Celsius for a rectangular and circular diaphragm, respectively. The measurement results demonstrate the feasibility of the proposed pressure sensor as a highly sensitive circuit-integrated pressure sensor.
- KSP Keywords
- CMOS-compatible, Circular diaphragm, Highly sensitive, Selectively etching, Sensor design, Side-wall, Silicon substrate, Surface micromachined, Temperature Coefficient, Vacuum Cavity, Vacuum sealing