Characterization of CMOS-MEMS Resonant Pressure Sensors

Comprehensive characterization results of CMOS-microelectromechanical systems resonant pressure sensor are presented. We have extensively evaluated the key performance parameters of our device in terms of quality factor (Q) variations under variable conditions of temperature and pressure, characterized by Knudsen number (K-n). The fundamental frequency of the reported device is 104.3 kHz. Over the full-scale pressure range of 0.1 to 100 kPa and a temperature range of -10 degrees C to 85 degrees C, Q from 450 to 62.6 have been obtained. Besides, static variations of the device capacitance have been measured and analyzed with temperature to evaluate the spring softening and the pull-in effects. A nonlinearity analysis has been performed to assess the device stability. Furthermore, a statistical mismatch analysis has been carried out to determine the deviation of resonance with etching time and ascertain maximum device yield. With our in-house back-end of line metal-layer release, this sensor can be monolithically embedded in the same substrate as standard CMOS integrated circuits, resulting in a significant cost and area reduction.