Microelectromechanical sensing structure for a capacitive acoustic transducer including an element limiting the oscillations of a membrane, and manufacturing method thereof

摘要

A microelectromechanical sensing structure for a capacitive acoustic transducer, including: a semiconductor substrate; a rigid electrode; and a membrane set between the substrate and the rigid electrode, the membrane having a first surface and a second surface, which are in fluid communication, respectively, with a first chamber and a second chamber, respectively, the first chamber being delimited at least in part by a first wall portion and a second wall portion formed at least in part by the substrate, the second chamber being delimited at least in part by the rigid electrode, the membrane being moreover designed to undergo deformation following upon incidence of pressure waves and facing the rigid electrode so as to form a sensing capacitor having a capacitance that varies as a function of the deformation of the membrane. The structure moreover includes a beam, which is connected to the first and second wall portions and is designed to limit the oscillations of the membrane.

主权项

1. A microelectromechanical sensing structure, comprising:
a substrate of semiconductor material; a sensing capacitor that includes:
a rigid conductive electrode;a conductive membrane coupled to the substrate and arranged between the substrate and the electrode, the membrane having a first surface and a second surface, the membrane being configured to deform in response to pressure, the sensing capacitor having a capacitance that varies as a function of the deformation of the membrane; a first chamber delimited at least in part by the substrate and the first surface of the membrane; a second chamber being delimited at least in part by the electrode and the second surface of the membrane; and a beam located in the first chamber and coupled to the substrate, the beam being configured to limit oscillations of the membrane when the pressure has an amplitude that is above a first threshold, thereby preventing plastic deformation of the membrane.