A Laterally Driven Micromachined Resonant Pressure Sensor

Abstract

** SUMMARY A new type of resonant pressure sensor is presented which employs a laterally driven resonant strain gauge. The resonant strain gauge is designed using simple linear elastic theory and the sensor fabricated by a combination of bulk and surface micromachining techniques. The strain gauge is driven electrostatically and the resultant vibration sensed capacitively. Its lateral mode of oscillation offers several advantages such as a low sensitivity of the Qfactor to cavity gases. The Q-factor has been estimated to be 50 000 in vacuum and preliminary measurements have shown a pressure sensitivity of 8.8 kHzBar with a Qfactor of about 200 in air.