Angular accelerometers are described, as are systems employing such accelerometers. The angular accelerometers may include a proof mass and rotational acceleration detection beams directed toward the center of the proof mass. The angular accelerometers may include sensing capabilities for angular acceleration about three orthogonal axes. The sensing regions for angular acceleration about one of the three axes may be positioned radially closer to the center of the proof mass than the sensing regions for angular acceleration about the other two axes. The proof mass may be connected to the substrate though one or more anchors.

According to some aspects of the subject technology, an apparatus includes an accelerometer including one or more sense electrodes to sense an input acceleration, and an unstick device to free the accelerometer from a stuck state due to a saturating acceleration input. The unstick device includes at least one unstick electrode and a control circuitry to cause the unstick electrode to generate vibrational energy to free the accelerometer.

A micromechanical device including a substrate, a movable mass, and a stop spring structure, which includes a stop. The substrate includes a substrate surface in parallel to a main extension plane and the movable mass is situated movably above the substrate surface in relation to the substrate. The stop spring structure is connected to the movable mass. The stop is designed to strike against the substrate surface in the event of a deflection of the movable mass in a z direction, perpendicular to the main extension plane. The stop spring structure, at the location of the stop, includes a first spring constant, a second spring constant, in parallel to the main extension plane, and a third spring constant, in parallel to the main extension plane and perpendicular to the x direction. The first spring constant is greater than the second spring constant and/or is greater than the third spring constant.

A MEMS inertial sensor includes a supporting structure and an inertial structure. The inertial structure includes at least one inertial mass, an elastic structure, and a stopper structure. The elastic structure is mechanically coupled to the inertial mass and to the supporting structure so as to enable a movement of the inertial mass in a direction parallel to a first direction, when the supporting structure is subjected to an acceleration parallel to the first direction. The stopper structure is fixed with respect to the supporting structure and includes at least one primary stopper element and one secondary stopper element. If the acceleration exceeds a first threshold value, the inertial mass abuts against the primary stopper element and subsequently rotates about an axis of rotation defined by the primary stopper element. If the acceleration exceeds a second threshold value, rotation of the inertial mass terminates when the inertial mass abuts against the secondary stopper element.

A device includes a micro-electromechanical system (MEMS) device layer comprising a proof mass. The proof mass includes a first proof mass portion and a second proof mass portion. The first proof mass portion is configured to move in response to a stimuli. The second proof mass portion has a spring attached thereto. The device further includes a substrate disposed parallel to the MEMS device layer. The substrate comprises a bumpstop configured to limit motion of the first proof mass portion. The device includes a first electrode disposed on the substrate facing the second proof mass portion. The first electrode is configured to apply a pulling force onto the second proof mass portion and to move the second proof mass portion towards the first electrode.

Selective self-assembled monolayer patterning with sacrificial layer for devices is provided herein. A sensor device can include a handle layer and a device layer that comprises a first side and a second side. First portions of the first side are operatively connected to defined portions of the handle layer. At least one area of the second side comprises an anti-stiction area formed with an anti-stiction coating. The device can also include a Complementary Metal-Oxide-Semiconductor (CMOS) wafer operatively connected to second portions of the second side of the device layer. The CMOS wafer comprises at least one bump stop. The anti-stiction area faces the at least one bump stop.

A MEMS device comprising a substrate comprising a die and a plurality of side-walls disposed upon the MEMS die, a proof-mass coupled to the substrate, the proof-mass is configured to be displaced within a first plane that is parallel to the die, wherein the proof-mass is configured to contact at least a sidewall, wherein the proof-mass is configured to adhere to the side-wall as a result of stiction forces, a driving circuit configured to provide a driving voltage in response to a driving signal indicating that the proof-mass is adhered to the side-wall, and an actuator coupled to the driving circuit disposed upon the side-wall, wherein the actuator is configured to receive a driving voltage and to provide an actuator force to the proof mass within the first plane in a direction away from the side-wall in response to the driving voltage, wherein the actuator force exceeds the stiction forces.

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.

Angular accelerometers are described, as are systems employing such accelerometers. The angular accelerometers may include a proof mass and rotational acceleration detection beams directed toward the center of the proof mass. The angular accelerometers may include sensing capabilities for angular acceleration about three orthogonal axes. The sensing regions for angular acceleration about one of the three axes may be positioned radially closer to the center of the proof mass than the sensing regions for angular acceleration about the other two axes. The proof mass may be connected to the substrate though one or more anchors.

In some embodiments, a sensor includes a microelectromechanical system (MEMS) structure, a cover, and a bump stop. The MEMS structure is configured to move responsive to electromechanical stimuli. The cover is positioned on the MEMS structure. The cover is configured to mechanically protect the MEMS structure. The bump stop is disposed on a substrate and the bump stop is configured to stop the MEMS structure from moving beyond a certain point. The bump stop is further configured to stop the MEMS structure from making physical contact with the substrate. Moreover, the cover is configured to apply a force to the MEMS structure responsive to a voltage being applied to the cover.