Temperature compensating pressure sensor having active and reference membranes

Abstract

Provided is a temperature compensating pressure sensor. The sensor includes a silicon substrate having sealed channels on which is deposited a CMOS layer, and a conductive layer and a passivation layer deposited on the CMOS layer, the conductive layer representing a first electrode. The sensor 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. Also included is a cap which covers the membranes, said cap having a channel to expose the active membrane to an outside fluid pressure, with the membranes representing a second electrode. The active membrane deflects due to differential stresses so that the first and second electrodes develop a capacitance C between them depending on the electrical permittivity of the fluid, with the reference membrane providing a temperature compensating reference capacitance.

Dependencies are inferred from the claim text.