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.