Ultrasensitive micromachined bulk acoustic wave resonators based vacuum gauges and their optimization

A novel and highly sensitive vacuum gauge based on a micromachined AT-cut quartz bulk acoustic wave (BAW) resonator diaphragm is presented. Pressure is sensed by monitoring frequency shifts of these resonators due to the sensor's diaphragm bending. The sensors show a large dynamic range of 1 mTorr–760 Torr with a resolution ∼1.06 mTorr for 82.4 MHz resonators with a high linearity. Here we report on the parametric study to improve sensitivity of these sensors.