A structure forming method according to an aspect is a structure forming method for forming a first hole and a second hole having width smaller than width of the first hole in a substrate with dry etching and forming a structure. The structure forming method includes forming an etching mask on the substrate, etching a portion of the etching mask overlapping a first hole forming region where the first hole is formed, etching a portion of the etching mask overlapping a second hole forming region where the second hole is formed, and performing the dry etching of the substrate using the etching mask as a mask.

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.

A combined MicroElectroMechanical structure (MEMS) includes a first piezoelectric membrane having one or more first electrodes, the first piezoelectric membrane being affixed between a first holder and a second holder; and a second piezoelectric membrane having an inertial mass and one or more second electrodes, the second piezoelectric membrane being affixed between the second holder and a third holder.

An inertial sensor such as a MEMS accelerometer or gyroscope has a proof mass that is driven by a self-test signal, with the response of the proof mass to the self-test signal being used to determine whether the sensor is within specification. The self-test signal is provided as a non-periodic self-test pattern that does not correlate with noise such as environmental vibrations that are also experienced by the proof mass during the self-test procedure. The sense output signal corresponding to the proof mass is correlated with the non-periodic self-test signal, such that an output correlation value corresponds only to the proof mass response to the applied self-test signal.

An acceleration sensor includes: a semiconductor substrate that includes a support substrate and a semiconductor layer; a first-direction movable electrode; a second-direction movable electrode; a first-direction fixed electrode; a second-direction fixed electrode; and a support member. The acceleration sensor is configured to detect acceleration in a first direction in the surface direction of the semiconductor substrate and acceleration in a second direction orthogonal to the first direction and parallel to the surface direction. The first-direction movable electrode and the first-direction fixed electrode are provided such that an angle formed by an extended direction of the first-direction movable electrode and the first-direction fixed electrode and the second direction is sin.sup.−1(d/L)[deg], and the second-direction movable electrode and the second-direction fixed electrode are provided such that an angle formed by an extended direction of the second-direction movable electrode and the second-direction fixed electrode and the first direction is sin.sup.−1(d/L)[deg].

A micro-electro-mechanical system (MEMS) motion sensor is provided that includes a MEMS wafer having a frame structure, a plurality of proof masses suspended to the frame structure, movable in three dimensions, and enclosed in one or more cavities. The MEMS sensor includes top and bottom cap wafers bonded to the MEMS wafer and top and bottom electrodes provided in the top and bottom cap wafers, forming capacitors with the plurality of proof masses, and being together configured to detect motions of the plurality of proof masses. The MEMS sensor further includes first electrical contacts provided on the top cap wafer and electrically connected to the top electrodes, and a second electrical contacts provided on the top cap wafer and electrically connected to the bottom electrodes by way of vertically extending insulated conducting pathways. A method for measuring acceleration and angular rate along three mutually orthogonal axes is also provided.

A semiconductor device includes a substrate, a beam, a movable structural body, a first stopper member, a second stopper member and a third stopper member. The first stopper member is arranged with a first gap from the movable structural body in an in-plane direction. The second stopper member is arranged with a second gap from the movable structural body in an out-of-plane direction. The third stopper member is arranged opposite to the second stopper member with the movable structural body interposed therebetween in the out-of-plane direction, and is arranged with a third gap from the movable structural body. Consequently, there can be provided a semiconductor device in which excessive displacement of the movable structural body can be suppressed to thereby suppress damage to and breakage of the beam supporting the movable structural body, and a method of manufacturing the same.

A micromechanical sensor that is produced surface-micromechanically includes at least one mass element formed in a third functional layer that is non-perforated at least in certain portions. The sensor has a gap underneath the mass element that is formed by removal of a second functional layer and at least one oxide layer. The removal of the at least one oxide layer takes place by introducing a gaseous etching medium into a defined number of etching channels arranged substantially parallel to one another. The etching channels are configured to be connected to a vertical access channel in the third functional layer.

A hinge for a microelectromechanical system includes a fixed part and a part movable relative to the fixed part along at least an out-of-plane direction, the hinge being intended to suspend the moving part from the fixed part. The hinge includes a first rigid part, a second part fixed to the first part at one end and intended to be anchored to the fixed part or the moving part. The second part deforms in bending in a first direction, two third parts are fixed to the first part and are anchored to the moving part or the fixed part, and the third parts deform in bending along a second direction orthogonal to the first direction.

Small form-factor MEMS devices and methods of using the devices are disclosed. An exemplary MEMS device includes an accelerometer contact microphone. Certain devices described herein comprise nanometer scale sensing gaps in the out-of-plane direction to increase vibration sensitivity in a vacuum casing. Certain devices described herein provide a differential sensing mechanism. The disclosure also describes accelerometer contact microphones having an operational bandwidth ranging from 0 Hz and 10,000 Hz. The vibration acceleration sensitivity of certain devices described herein is better 100 μg√Hz.