A physical quantity sensor detects a physical quantity in at least one of a first direction and a second direction. The physical quantity sensor includes a fixed electrode unit provided on a substrate, a movable body including a movable electrode unit provided such that movable electrodes face fixed electrodes of the fixed electrode unit, a fixed portion fixed to the substrate, a support beam having one end coupled to the fixed portion and the other end coupled to the movable body, and a restricting unit configured to restrict displacement of the movable body. The restricting unit includes a first portion having one end coupled to the movable body and extending in the first direction, and a second portion having one end coupled to the other end of the first portion and extending in the second direction.

A mechanism for reducing stiction in a MEMS device by decreasing surface area between two surfaces that can come into close contact is provided. Reduction in contact surface area is achieved by increasing surface roughness of one or both of the surfaces. The increased roughness is provided by forming a micro-masking layer on a sacrificial layer used in formation of the MEMS device, and then etching the surface of the sacrificial layer. The micro-masking layer can be formed using nanoclusters. When a next portion of the MEMS device is formed on the sacrificial layer, this portion will take on the roughness characteristics imparted on the sacrificial layer by the etch process. The rougher surface decreases the surface area available for contact in the MEMS device and, in turn, decreases the area through which stiction can be imparted.

A micromechanical component for a sensor device. The component includes a first seismic mass, the first seismic mass displaced out of its first position of rest by a first limit distance into a first direction along a first axis mechanically contacting a first stop structure, and including a second seismic mass which is displaceable out of its second position of rest at least along a second axis, the second axis lying parallel to the first axis or on the first axis, and a second stop surface of the second seismic mass, displaced out of its second position of rest into a second direction counter to the first direction along the second axis, mechanically contacting a first stop surface of the first seismic mass adhering to the first stop structure.

Various embodiments of the invention provide for stiction testing in MEMS devices, such as accelerometers. In certain embodiments, testing is accomplished by a high voltage smart circuit that enables an analog front-end circuit to accurately read the position of a movable proof-mass relative to a biased electrode in order to allow the detection of both contact and release conditions. Testing allows to detect actual or potential stiction failures and to reject defective parts in a Final Test stage of a manufacturing process where no other contributors to stiction issue can occur, thereby, minimizing stiction failure risks and extending the reliability of MEMS devices.

An inertial sensor includes a substrate, a first supporting beam being a first rotation axis extending along a first direction, a first movable member swingable around the first rotation axis, a second supporting beam being a second rotation axis extending along a second direction crossing the first direction, a second movable member swingable around the second rotation axis, a third rotation axis extending along a second direction, a third movable member swingable around the third rotation axis, and a projection, wherein the second and third movable members are line-symmetrically placed with a center line of the first movable member along the second direction as an axis of symmetry, a center of gravity of the second movable member is closer to the center line than the second supporting beam, and a center of gravity of the third movable member is closer to the center line than the third supporting beam.

A sensor includes a movable element adapted for rotational motion about a rotational axis due to acceleration along an axis perpendicular to a surface of a substrate. The movable element includes first and second ends, a first section having a first length between the rotational axis and the first end, and a second section having a second length between the rotational axis and the second end that is less than the first length. A motion stop extends from the second end of the second section. The first end of the first section includes a geometric stop region for contacting the surface of the substrate at a first distance away from the rotational axis. The motion stop for contacting the surface of the substrate at a second distance away from the rotational axis. The first and second distances facilitate symmetric stop performance between the geometric stop region and the motion stop.

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 physical quantity sensor includes a substrate and a movable body. A first region to an n-th region in which a step is provided between adjacent regions are provided on a first surface of a first mass portion of the movable body. Ends of the first region to the n-th region on a side far from the rotation axis are referred to as a first end to an n-th end. In a state in which the movable body is maximally displaced around the rotation axis AY, when a virtual straight line passing through two ends of the first end to the n-th end and having a smallest angle with respect to the X axis is set as a first virtual straight line, and a straight line along a main surface of a first fixed electrode is set as a second virtual straight line, the first virtual straight line and the second virtual straight line do not intersect with each other in a region between a first normal line intersecting with an end of the first fixed electrode of the substrate closest to the rotation axis AY and a second normal line intersecting with an end of the first fixed electrode farthest from the rotation axis.

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.

A physical quantity sensor includes a substrate, a movable body that is provided displaceably in a state of being opposed to the substrate and is provided with a first through-hole and a second through-hole as through-holes, and a protrusion configured integrally with the substrate at a side of the movable body of the substrate, and in which the protrusion is provided at a position where the protrusion overlaps the through-hole and the movable body in plan view.