Silicon MEMS Pressure Sensors for Aerospace Applications

A novel piezoresistive silicon MEMS pressure sensor has been developed for full-scale measurement from 10 bar to > 1000 bar for high-precision oil & gas, aerospace and space applications. The silicon element has a tubular design with an externally stable resistor bridge to detect the pressure-induced stress. The fabrication process is by silicon planar technology and MEMS processes, such as silicon fusion bonding and electrochemical etching. The concept is favorable in rough field applications due to several key properties from small dimensions and deflections, high material rigidity, symmetry, a large output signal, fast pressure and temperature response and low acceleration sensitivity. The overload capability is several times the full-scale, since pressure mainly generates compressive stress. Long-term and hysteresis effects are minimized by eliminating the package-induced stress due to a relatively large distance from the die attach to the sensitive region. Total accuracy for a pressure range 700 bar and a wide temperature range −7 to 135°C is better than 0.01%FS. Typical hysteresis and repeatability is ± 10 ppm.