Abstract
We propose an on-chip film bulk acoustic resonator (FBAR) device based pressure sensor with a simple cavity structure. By sealing the back trench cavity of the FBAR device, the FBAR device become sensitive to the outside environmental pressure. The pressure sensor possesses two resonant peaks with high quality factors and coupling coefficients, which exhibit different temperature coefficients of frequency, and could be used as on-chip temperature compensation. The results show that mode 1 resonant peak of the FBAR pressure sensor has a pressure sensitivity of 1.642 ppm kPa−1, while that of mode 2 resonant peak is 0.1764 ppm kPa−1. Both of the two resonant peaks have high pressure response linearity above 0.999 in the pressure ranges of 17 kPa to 101 kPa and 101 kPa to 400 kPa. A method for temperature calibration is provided. The pressure sensor is simple in package and small in dimension, and the output data is frequency, which can easily be transmitted wirelessly, demonstrating great potential for applications such as the tire pressure monitor system.