Achievement of a high-sensitive and high-overload sensor based on the bossed-diaphragm structure

The paper presents a piezoresistive absolute micro-pressure sensor for altimetry. This investigation includes the design, fabrication and testing of the sensor. An improved structure is studied through incorporating sensitive beams into the bossed-diaphragm structure. By analyzing the stress distribution of sensitive elements using finite element method (FEM), the configuration shows an enhanced sensitivity and a proper overload resistance. Equations about surface stress and deflection of the sensor are established by multivariate fittings based on ANSYS loop calculation results. Structure dimensions are optimized and determined by MATLAB. Silicon bulk micromachining technology is utilized to fabricate the sensor prototype, and the processing is discussed. The outputs under both static and dynamic conditions are tested. Experimental results demonstrate the sensor features a relatively high sensitivity of 11.655 μV/V/Pa in the operating range of 500 Pa at room temperature and a proper overload resistance of 200 times overpressure to promise its survival under atmosphere. The favorable performances enable the sensor's application in measuring absolute micro pressure.