Enhanced Sensitivity of SAW-Based Pirani Vacuum Pressure Sensor

The authors have already presented a novel surface acoustic wave device for vacuum pressure measurement by employing a piezoelectric substrate that has a high value of temperature coefficient of frequency. Frequency-shift measurements as a function of vacuum pressure can be used to extract information about the pressure sensitivity of the device. In this paper, we report that the deposition of an aluminum thin-film layer and rise in the sensor's operating temperature significantly improve the sensitivity of the device. The results are crucial for improving the lower limit of the vacuum pressure measurement, which currently stands around 10^-3 Pa.