A new micromachined silicon high-accuracy pressure sensor

Abstract Sextant Avionique is currently developing a new family of micromachined silicon pressure sensors. The target accuracy is 10−4 full scale. Therefore, the basic principle uses a vibrating concept. A membrane is stressed by the pressure and this activates a vibrating beam, the frequency of which is related to the measured pressure. The sensing element is defined by three suitably micromachined silicon layers. The design is presented. This solution enables a vacuum to be sealed inside the silicon cell, thus diminishing the cost and the complexity of the packaging. Some realizations are presented. The metrological performance is then presented throughout the measurement range. This performance is compatible with the 10−4 full scale objective for the accuracy. These characteristics allow the utilization of the sensor for airborne air-data applications, as well as airborne engine-control applications, or groundbased applications where accuracy is needed, such as metrology.