A micro-pressure sensor with high sensitivity and overload resistance

Presented is a piezoresistive absolute micro-pressure sensor, which features relatively high sensitivity and overload resistance simultaneously. In this investigation, the design, fabrication and testing of the sensor are carried out. By analyzing the stress distribution on sensitive elements using the finite-element method (FEM), an improved structure through introduction of sensitive beams and islands is built up. The proposed configuration presents its advantages in terms of sensitivity and overload resistance compared with the bossed diaphragm and plane diaphragm structures. The sensor is fabricated based on silicon bulk micromachining technology, and the processing is discussed. Testing results demonstrate the sensor features a relatively high sensitivity of 16.544 μV/V/Pa in the operating range of 500 Pa at room temperature, and a proper overload resistance of 200 times overpressure. Due to the favorable characteristics, the sensor can be utilized in measuring absolute micro pressure.