High-stress and overrange behavior of sealed-cavity polysilicon pressure sensors

The overrange behavior of sealed-cavity polysilicon pressure sensors with full-scale pressures ranging from 35 to 300 psi (0.24 to 2.0 MPa) is investigated. Because of a built-in overpressure stop, rupture pressure between 3500 to 6000 psi (24 to 41 MPa) was observed. After repetitive cycles of overpressure to 3000 psi, no degradation in sensor performance was apparent, and the zero repeatability was better than 0.1% of span. These results demonstrate the outstanding overrange capabilities of sealed-cavity polysilicon sensors and the exceptional mechanical strength and reproducibility of polysilicon diaphragms for pressure sensing. The excellent built-in overrange protection represents a significant advantage of the sealed-cavity polysilicon sensors for industrial applications where high overrange pressure is common.<>