A diaphragm secondary stress utilization method for increasing the sensitivity of piezoresistive pressure sensors without sacrificing linearity

Piezoresistive pressure sensors with high sensitivity and linearity are critical for aerospace and other industries, however, attempts to improve sensitivity often reduce linearity. Therefore a diaphragm secondary stress utilization method (DSSUM) is proposed, which can significantly increase sensor sensitivity without sacrificing the linearity. The DSSUM realizes the detection of primary and secondary stresses on the diaphragm through the eight-piezoresistor Wheatstone bridge without changing the structure of the diaphragm. A differential pressure sensor with a measurement range of −15 ∼ 15 kPa has been designed and fabricated based on DSSUM. Comparative test results show that DSSUM can increase the sensitivity of the sensor by 50.32 % to 32.35 mV/kPa while maintaining the linearity at 0.031 %F.S. The repeatability of the sensor is 0.02 %FS, the hysteresis is 0.01 %FS, and the zero drift is 0.052 %FS. By using DSSUM, both wide-range and small-range pressure sensors can increase their sensitivity by more than 50 % without impacting linearity. The DSSUM offers a new method for achieving high-performance pressure sensors and holds potential for wide application.