Design of Piezoresistive pressure sensor for enhanced sensitivity

Piezoresistive pressure sensor is a significant transduction mechanism for measuring pressure due to the fact that it is simpler to integrate with electronics, its response is more linear, they are inherently shielded from RF noise and fabrication is easy compared to other transduction mechanism. In this paper, piezoresistive transduction mechanism is employed for design of a pressure sensor. The diaphragm of the proposed sensor is designed using n-type Silicon with p-type Silicon piezoresistors placed on the surface of a diaphragm in a Wheatstone bridge configuration at the most sensitive region of the diaphragm. The proposed design is analyzed to study the deflection of the diaphragm and the output voltage across the bridge. The effect of change in piezoresistor length on the output voltage is also investigated. The results reveal that the proposed sensor provides highest sensitivity for the piezoresistor length of 50um.