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Abstract

This invention concerns a capacitive pressure sensor construction and method for fabricating said sensor. The pressure sensor construction comprises a base part (1, 2, 4), comprising an electrically conductive silicon layer (1, 2) and a thereupon permanently bonded planar intermediate layer (4) of an insulating material with an essentially smaller thickness than that of the silicon layer (1, 2); a fixed planar capacitor electrode (9) fabricated on the base part (1, 2, 4); and a deflecting membranous capacitor electrode (6) fabricated of silicon and integral with a surrounding, essentially thicker base element (5), and gappedly spaced from and aligned at least approximately coincident with the fixed capacitor electrode (9), so that a hermetically sealed chamber (25) remains between the fixed electrode (9) and the membranous electrode (6). According to the invention, the base part (1, 2, 4) is perpendicularly divided into areas (1, 2) galvanically isolated from each other, namely to a contact area (2), which is coincident with the fixed capacitor electrode (9), galvanically connected to said electrode and designed with an area maximally equal to that of said electrode, and to at least one bonding area (1), which is isolated from the contact area (2) by an insulating layer (3) and to which a bonding voltage can be applied during the anodic bonding process in order to bond the base part to the base element (5) of the membranous capacitor electrode. The construction avoids stray capacitances at bonding area.

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First Claim