A PMUT includes a substrate, a membrane, and a sacrificial layer. The substrate has a cavity penetrating the substrate. The membrane is disposed over the cavity and includes a first piezoelectric layer, a bottom electrode, a top electrode, and a second piezoelectric layer. The first piezoelectric layer is disposed over the cavity and includes an anchor portion, where the anchor portion of the first piezoelectric layer is in direct contact with the substrate. The top and bottom electrodes are disposed over the first piezoelectric layer. The second piezoelectric layer is disposed between the bottom electrode and the top electrode. The sacrificial layer is disposed between the substrate and the first piezoelectric layer, and a vertical projection of the sacrificial layer does not overlap a vertical projection of portions of the membrane disposed over the cavity.

An exemplary method includes forming a sacrificial layer along sidewalls of an array of trenches that are indented into a substrate, depositing a fill layer over the sacrificial layer, and then creating an array of gaps between the fill layer and the substrate by removing the sacrificial layer along the sidewalls of the trenches, while maintaining a structural connection between the substrate and the fill layer at the floors of the trenches. The method further includes covering the substrate, the fill layer, and the gaps with a cap layer that seal fluid-tight against the substrate and the fill layer. The method further includes indenting a first reservoir and a second reservoir through the cap layer, and into the substrate and the fill layer, across the lengths of the array of gaps, so that the array of gaps connects the first reservoir in fluid communication with the second reservoir.

A PMUT includes a substrate, a membrane, and a sacrificial layer. The substrate has a cavity penetrating the substrate. The membrane is disposed over the cavity and includes a first piezoelectric layer, a bottom electrode, a top electrode, and a second piezoelectric layer. The first piezoelectric layer is disposed over the cavity and includes an anchor portion, where the anchor portion of the first piezoelectric layer is in direct contact with the substrate. The top and bottom electrodes are disposed over the first piezoelectric layer. The second piezoelectric layer is disposed between the bottom electrode and the top electrode. The sacrificial layer is disposed between the substrate and the first piezoelectric layer, and a vertical projection of the sacrificial layer does not overlap a vertical projection of portions of the membrane disposed over the cavity.

A piezoelectric micromachined ultrasonic transducer (PMUT) includes a substrate, a stopper, and a membrane, where the substrate and the stopper are composed of same single-crystalline material. The substrate has a cavity penetrating the substrate, and the stopper protrudes from a top surface of the substrate and surrounds the edge of the cavity. The membrane is disposed over the cavity and attached to the stopper.

A method includes obtaining an active device layer. The active device layer has a first surface with one or more active feature areas. First portions of the active feature areas are exposed, and second portions of the active feature areas are covered by an insulating layer. A conformal overcoat layer is formed on the first surface. A base of a microelectromechanical systems (MEMS) device layer is formed on the conformal overcoat layer. The MEMS device layer is spatially segregated from the active feature areas by removing portions of the base of the MEMS device layer in one or more antiparasitic regions (APRs) that correspond to the active feature areas. Metal MEMS features are formed on the base of the MEMS device layer. Selected portions of the active feature areas are exposed removing portions of the conformal overcoat layer that overlay the active feature areas.

In an embodiment a semiconductor transducer device includes a semiconductor body and a diaphragm having a first layer and a second layer, wherein a main extension plane of the diaphragm is arranged parallel to a surface of the semiconductor body, wherein the diaphragm is suspended at a distance from the semiconductor body in a direction perpendicular to the main extension plane of the diaphragm, wherein the second layer comprises titanium and/or titanium nitride, wherein the first layer comprises a material that is resistant to an etchant comprising fluorine or a fluorine compound, and wherein the second layer is arranged between the semiconductor body and the first layer.

A method of forming at least one Micro-Electro-Mechanical System (MEMS) includes patterning a wiring layer to form at least one fixed plate and forming a sacrificial material on the wiring layer. The method further includes forming an insulator layer of one or more films over the at least one fixed plate and exposed portions of an underlying substrate to prevent formation of a reaction product between the wiring layer and a sacrificial material. The method further includes forming at least one MEMS beam that is moveable over the at least one fixed plate. The method further includes venting or stripping of the sacrificial material to form at least a first cavity.

A process for fabricating a device for detecting electromagnetic radiation includes the step of providing a detecting element suspended by a supporting pillar. The pillar has a lateral through-aperture formed via a local break in the continuity of a layer of interest, because of the presence of a jut in a vertical orifice.

A method of forming an ultrasonic transducer device involves depositing a first layer on a substrate, depositing a second layer on the first layer, patterning the second layer at a region corresponding to a location of a transducer cavity, depositing a third layer that refills regions created by patterning the second layer, planarizing the third layer to a top surface of the second layer, removing the second layer, conformally depositing a fourth layer over the first layer and the third layer, defining the transducer cavity in a support layer formed over the fourth layer; and bonding a membrane to the support layer.

Provided is a MEMS microphone structure (1) and, more particularly, to a MEMS microphone structure (1) that ensures excellent sensitivity by including and/or forming a lower electrode (410) and an upper electrode (430) with a diaphragm (110) in a bending area (A1) so that the maximum bending displacement of the diaphragm (110) is controlled by a dielectrophoretic (DFP) force together with sound pressure.