Silicon Multi-Stage Current-Mode Piezoresistive Pressure Sensor

This paper describes the project of a Silicon Multi-Stage Current-Mode Piezoresistive Pressure Sensor fabricated at our in-house foundry (CCS-UNICAMP). This current-mode pressure sensor is an alternative to the conventional piezoresistive pressure sensors based on the Wheatstone Bridge or four-terminal devices. This sensor is based on the three-terminal pressure sensors. In three-terminal devices, one terminal is used as biasing terminal while the other two are the output terminals. The output signal is proportional to the current mismatching AI_bias between two output terminals. By considering multiple pairs of output terminals, the influence of the geometry of the sensor over its sensitivity is verified. The Piezoresistive Sensing Element (PSE) is entirely integrated and designed in such a way that its sensitivity is maximized. The experimental maximum differential sensitivity of the sensor output current relative change amounts to about 0.6%/psi.