A micro-electromechanical-system (MEMS) device may be formed to include an anti-stiction polysilicon layer on one or more moveable MEMS structures of a device wafer of the MEMS device to reduce, minimize, and/or eliminate stiction between the moveable MEMS structures and other components or structures of the MEMS device. The anti-stiction polysilicon layer may be formed such that a surface roughness of the anti-stiction polysilicon layer is greater than the surface roughness of a bonding polysilicon layer on the surfaces of the device wafer that are to be bonded to a circuitry wafer of the MEMS device. The higher surface roughness of the anti-stiction polysilicon layer may reduce the surface area of the bottom of the moveable MEMS structures, which may reduce the likelihood that the one or more moveable MEMS structures will become stuck to the other components or structures.

The present disclosure is directed to a MEMS gyroscope formed by a substrate and a movable mass suspended on the substrate and configured to carry out a movement in a driving direction and in a detection direction perpendicular to each other. The movable mass has a first face and a second face opposite to the first face. The gyroscope also has a first and a second quadrature compensation electrode group, fixed to the substrate and capacitively coupled to the movable mass. The first quadrature compensation electrode group faces the first face of the movable mass, and the second quadrature compensation electrode group faces the second face of the movable mass. The first and the second quadrature compensation electrode groups each have a respective variable facing area on the movable mass as a result of the movement of the movable mass in the driving direction and are configured to exert an electrostatic force on the movable mass during the movement of the movable mass in the driving direction.

A microelectromechanical device having a first substrate of semiconductor material and a second substrate of semiconductor material having a bonding recess delimited by projecting portions, monolithic therewith. The bonding recess forms a closed cavity with the first substrate. A bonding structure is arranged within the closed cavity and is bonded to the first and second substrates. A microelectromechanical structure is formed in a substrate chosen between the first and second substrates. The device is manufactured by forming the bonding recess in a first wafer; depositing a bonding mass in the bonding recess, the bonding mass having a greater depth than the bonding recess; and bonding the two wafers.

A microelectromechanical system (MEMS) sensor device includes a package housing having a top member, bottom member, and a spacer coupled the top member to the bottom member, defining a cavity. At least one sensor circuit and a MEMS sensor disposed within the cavity of the package housing. A first opening formed on the package housing a control device embedded within the package housing is electrically coupled to the sensor circuit and is controlled to tune the MEMS sensor from a directional mode to an omni-directional mode.

A method embodiment includes providing a MEMS wafer comprising an oxide layer, a MEMS substrate, a polysilicon layer. A carrier wafer comprising a first cavity formed using isotropic etching is bonded to the MEMS, wherein the first cavity is aligned with an exposed first portion of the polysilicon layer. The MEMS substrate is patterned, and portions of the sacrificial oxide layer are removed to form a first and second MEMS structure. A cap wafer including a second cavity is bonded to the MEMS wafer, wherein the bonding creates a first sealed cavity including the second cavity aligned to the first MEMS structure, and wherein the second MEMS structure is disposed between a second portion of the polysilicon layer and the cap wafer. Portions of the carrier wafer are removed so that first cavity acts as a channel to ambient pressure for the first MEMS structure.

A method of fabricating a MEMS device includes depositing an expandable material into a first recess of a cap wafer. The cap wafer includes a plurality of walls that surround and define the first recess and a second recess. The cap wafer is bonded to a MEMS wafer including a first MEMS device and a second MEMS device. The first MEMS device is encapsulated in the first recess, and the second MEMS device is encapsulated in the second recess. The expandable material is then heated to at least an activation temperature to cause the expandable material to expand after the first recess has been sealed. The expansion of the expandable material causes a reduction in volume of the first recess.

Microelectromechanical sensor comprising a fixed part and a mobile part suspended from the fixed part such that the mobile part can move at least in an out-of-plane displacement direction, the fixed part comprising at least first electrodes extending parallel to the displacement direction of the mobile part, the mobile part comprising a seismic mass and at least second electrodes extending parallel to the out-of-plane displacement direction, the first electrodes and the second electrodes being located relative to each other so as to be interdigitated, in which the second electrodes are directly connected to the inertial mass and only part of the face of each mobile electrode is facing an electrode fixed at rest.

A microsystem includes a substrate; a main part connected to the substrate via an anchor; a moving part configured to rotate about an axis of rotation O; a first beam connecting the moving part to the main part, the main direction of said first beam being along a first vector e.sub.j1 having as origin the junction of the moving part with the first beam and in the sense of the main part; a second beam connecting the moving part to the main part, the main direction of the second beam being along a second vector e.sub.j2 having as origin the junction of the moving part with the second beam and in the sense of the main part.

A micro-electromechanical apparatus includes a rotary element, at least one restraint and at least two folded springs. The rotary element is capable of rotating with respect to an axis. The folded springs are symmetrically disposed about the axis. Each folded spring has a moving end and a fixed end, the moving end is connected to the rotary element, and the fixed end is connected to the at least one restraint. The moving end is not located on the axis, and the fixed end is not located on the axis. A moving distance is defined as a distance between the moving end and the axis, a fixed distance is defined as a distance between the fixed end and the axis. A spring length is defined as a distance between the moving end and the fixed end. The spring length is varied according to the rotation of the rotary element.

An inertial structure is elastically coupled through a first elastic structure to a supporting structure so as to move along a sensing axis as a function of a quantity to be detected. The inertial structure includes first and second inertial masses which are elastically coupled together by a second elastic structure to enable movement of the second inertial mass along the sensing axis. The first elastic structure has a lower elastic constant than the second elastic structure so that, in presence of the quantity to be detected, the inertial structure moves in a sensing direction until the first inertial mass stops against a stop structure and the second elastic mass can move further in the sensing direction. Once the quantity to be detected ends, the second inertial mass moves in a direction opposite to the sensing direction and detaches the first inertial mass from the stop structure.