Mems capacitive pressure sensor

Abstract

A pressure sensor measures pressure by measuring the deflection of a MEMS membrane using a capacitive read-out method. There are two ways to implement the invention. One involves the use of an integrated Pirani sensor and the other involves the use of an integrated resonator, to function as a reference pressure sensor, for measuring an internal cavity pressure.

Description

technical field [0001] The present invention relates to MEMS capacitive pressure sensors. Background technique [0002] MEMS pressure sensors typically have piezoresistive or capacitive readout and are well known in the art. [0003] exist figure 1 A SEM cross-section of an example of a capacitive MEMS pressure sensor is shown in . The figure shows the device after sacrificial layer etching and closing of the etched holes with a 2 μm thick PECVD SiN film as one of the last thin film fabrication steps. [0004] The sensor has a suspended SiN film. The cavity under the SiN thin film is hermetically sealed by using the PEVCD SiN process. The final device performance is largely determined by the geometric, physical, mechanical and structural properties of this thin film. The density and composition of the film determine the airtightness, outgassing behavior and internal stresses. The stress together with the SiN thickness determines the stiffness of the membrane and thus t...

AI Technical Summary

Problems solved by technology

[0017] Currently, there is no way to perform self-calibration and correct for signal drift in an industrial environment

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