A process for transferring a useful layer to a carrier substrate including a first surface is provided, the process including the steps of: providing a donor substrate including a first surface, a weakened zone including implanted species, the useful layer, which is bounded by the weakened zone and by the first surface of the donor substrate, and an amorphous zone disposed, in the useful layer, parallel to the weakened zone; assembling, on a side of the first surface of the donor substrate and on a side of the first surface of the carrier substrate, the donor substrate with the carrier substrate by bonding, such that the amorphous zone is at least partially facing at least one cavity that is partially bounded by the first surface of the donor substrate; and splitting the donor substrate along the weakened zone so as to reveal the useful layer.

A preparation method for a micro-electromechanical systems (MEMS) microphone includes the steps of: providing a silicon substrate having a silicon surface; forming an enclosed cavity in the silicon substrate; forming a plurality of spaced apart acoustic holes in the silicon substrate, each acoustic hole having two openings, one of which communicating with the cavity and the other one located on the silicon surface; forming a sacrificial layer on the silicon substrate, which includes a first filling portion, a second filling portion and a shielding portion; forming a polysilicon layer on the shielding portion; forming a recess in the silicon substrate on the side away from the silicon surface; and removing the first filling portion, the second filling portion and part of the shielding portion so that the recess is brought into communication with the cavity to form a back chamber, and that the polysilicon layer, the remainder of the shielding portion and the silicon substrate together delimit a hollow chamber, the hollow chamber communicating with the opening of the plurality of acoustic holes away from the cavity, completing the MEMS microphone.

A process for fabricating a micromechanical structure made of silicon carbide including a cavity, from a stack including a first silicon-carbide layer and a silicon layer on the first silicon-carbide layer, the process including shaping the silicon layer so as to form a discrete silicon structure on the first silicon-carbide layer. The process further includes, after the shaping of the silicon layer, a carbonization to initiate the removal of the discrete silicon structure; depositing a second silicon-carbide layer; and an annealing step, the discrete silicon structure being entirely removed at the end of the annealing.

A MEMS device comprising a body, having a first surface and a second surface; a diaphragm cavity in the body extending from the second surface of the body; a deformable portion in the body between the first surface and the diaphragm cavity; and a piezoelectric actuator, extending on the first surface of the body, over the deformable portion. The MEMS device is characterized in that it comprises a recess structure extending in the body and delimiting a stopper portion for the deformable portion.

A pressure sensor designed to detect a value of ambient pressure of the environment external to the pressure sensor includes: a first substrate having a buried cavity and a membrane suspended over the buried cavity; a second substrate having a recess, hermetically coupled to the first substrate so that the recess defines a sealed cavity the internal pressure value of which provides a pressure-reference value; and a channel formed at least in part in the first substrate and configured to arrange the buried cavity in communication with the environment external to the pressure sensor. The membrane undergoes deflection as a function of a difference of pressure between the pressure-reference value in the sealed cavity and the ambient-pressure value in the buried cavity.

A micro-electro-mechanical device formed in a monolithic body of semiconductor material accommodating a first buried cavity; a sensitive region above the first buried cavity; and a second buried cavity extending in the sensitive region. A decoupling trench extends from a first face of the monolithic body as far as the first buried cavity and laterally surrounds the second buried cavity. The decoupling trench separates the sensitive region from a peripheral portion of the monolithic body.

A method for manufacturing a MEMS device includes a hole forming step of forming a plurality of holes concaved from a principal surface in a substrate material including a semiconductor, a connecting-hollow-portion forming step of forming a connecting hollow portion that connects the plurality of holes together, and a movable-portion forming step of, by partially moving the semiconductor of the substrate material so as to close at least one part of the plurality of holes, forming a hollow portion that exists inside the substrate material and a movable portion that coincides with the hollow portion when viewed in a thickness direction of the substrate material.

A process for manufacturing a MEMS pressure sensor having a micromechanical structure envisages: providing a wafer having a substrate of semiconductor material and a top surface; forming a buried cavity entirely contained within the substrate and separated from the top surface by a membrane suspended above the buried cavity; forming a fluidic-communication access for fluidic communication of the membrane with an external environment, set at a pressure the value of which has to be determined; forming, suspended above the membrane, a plate made of polysilicon, separated from the membrane by an empty space; and forming electrical-contact elements for electrical connection of the membrane and of the plate, which are designed to form the plates of a sensing capacitor, the value of capacitance of which is indicative of the value of pressure to be detected. A corresponding MEMS pressure sensor having the micromechanical structure is moreover described.

A method for forming a microelectromechanical systems (MEMS) device may include performing a first silicon-on-nothing process to form a first cavity in a substrate. The method may include depositing an epitaxial layer on a surface of the substrate. The method may include performing a second silicon-on-nothing process to form a second cavity in the epitaxial layer. The method may include exposing the first cavity and the second cavity by removing a portion of the substrate and the epitaxial layer.

A MEMS device is formed by a body of semiconductor material which defines a support structure. A pass-through cavity in the body is surrounded by the support structure. A movable structure is suspended in the pass-through cavity. An elastic structure extends in the pass-through cavity between the support structure and the movable structure. The elastic structure has a first and second portions and is subject, in use, to mechanical stress. The MEMS device is further formed by a metal region, which extends on the first portion of the elastic structure, and by a buried cavity in the elastic structure. The buried cavity extends between the first and the second portions of the elastic structure.