High-performance film bulk acoustic wave pressure and temperature sensors

A film bulk acoustic wave resonator (FBAR)-based sensor for the simultaneous measurement of temperature and pressure with high sensitivity is fabricated and characterized. Temperature or pressure sensing is determined by the change in the series resonant frequency of the FBAR device when exposed to a measurement environment. For temperature sensing, measurement results show a sensitivity of 25.02 ppm/degrees C, a nonlinearity less than +/- 0.005% over the measurement range of 10 to 80 degrees C, and a hysteresis within +/- 0.005% in one temperature cycle. In pressure sensing, measured results show a sensitivity of 336.2 ppm/bar, a nonlinearity less than +/- 0.004% over the measurement pressure range of 0 to 2.07 bar, and a hysteresis within +/- 0.007% in one pressure cycle.