A Low Temperature Drifting Acoustic Wave Pressure Sensor with an Integrated Vacuum Cavity for Absolute Pressure Sensing

In this paper we demonstrate a novel acoustic wave pressure sensor, based on an aluminum nitride (AlN) piezoelectric thin film. It contains an integrated vacuum cavity, which is micro-fabricated using a cavity silicon-on-insulator (SOI) wafer. This sensor can directly measure the absolute pressure w...

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Bibliographic Details
Published in:Sensors (Basel, Switzerland) Switzerland), 2020-03, Vol.20 (6), p.1788
Main Authors: Wang, Tao, Tang, Zhengjie, Lin, Huamao, Zhan, Kun, Wan, Jiang, Wu, Shihao, Gu, Yuandong, Luo, Wenbo, Zhang, Wanli
Format: Article
Language:English
Subjects:
acoustic wave
Acoustic waves
Acoustics
Boundary conditions
Design
Electric fields
Electrodes
External pressure
Low temperature
Microelectromechanical systems
piezoelectric
pressure sensor
Pressure sensors
Propagation
Sensors
Simulation
Temperature
Temperature compensation
Thin films
vacuum cavity
Velocity
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Summary:In this paper we demonstrate a novel acoustic wave pressure sensor, based on an aluminum nitride (AlN) piezoelectric thin film. It contains an integrated vacuum cavity, which is micro-fabricated using a cavity silicon-on-insulator (SOI) wafer. This sensor can directly measure the absolute pressure without the help of an external package, and the vacuum cavity gives the sensor a very accurate reference pressure. Meanwhile, the presented pressure sensor is superior to previously reported acoustic wave pressure sensors in terms of the temperature drift. With the carefully designed dual temperature compensation structure, a very low temperature coefficient of frequency (TCF) is achieved. Experimental results show the sensor can measure the absolute pressure in the range of 0 to 0.4 MPa, while the temperature range is from 20 °C to 220 °C with a TCF of -14.4 ppm/°C. Such a TCF is only about half of that of previously reported works.
ISSN:1424-8220
1424-8220
DOI:10.3390/s20061788