Importance

Loading Importance Indicators...

Abstract

The invention provides for a pressure sensor with compensation for temperature variations. The sensor has CMOS layers deposited on a substrate, a conductive layer connected to the CMOS and a passivation layer deposited on the CMOS layers. The arrangement also includes a conductive active membrane spaced from the conductive layer to form an active chamber, and a conductive reference membrane spaced from the conductive layer to form a sealed reference chamber. Further included is a cap which covers the membranes, said cap exposing the active membrane to an outside fluid pressure. The active membrane further defines a foot which is located between the substrate and cap with a leg extending away from the substrate and terminating in a substantially planar deflectable portion, which deflects due to differential pressure stresses so that an active capacitance is developed between the active membrane and the conductive layer depending on the electrical permittivity e of the fluid. The reference membrane provides a temperature compensating reference capacitance. The arrangement also has sensor circuitry configured to determine a charge imbalance indicative of a pressure difference between the active and reference membranes.

Loading the Abstract Image...

First Claim