Airtightness in a cavity of an inertial sensor (acceleration sensor) is increased to achieve high sensitivity. In the acceleration sensor having movable electrodes VE1, VE2 and fixed electrodes FE1, FE2, the fixed electrodes are formed by portions surrounded by a through hole TH1 provided in a cap layer CL, and the through hole is filled with an insulating film IF1 and polysilicon P and has a wide portion (WP). The wide portion has a gap SP that is not filled with the insulating film IF1 and the polysilicon P, and the gap SP is filled with the interlayer insulating film ID. With such a configuration, degassing can be exhausted through the gap (airway) SP in a pressure reducing step.

A flexure for a MEMS device includes an elongated beam and a protrusion element extending outwardly from a sidewall of the elongated beam. A MEMS inertial sensor includes a movable element spaced apart from a surface of a substrate, an anchor attached to the substrate, and a spring system. The spring system includes first and second beams, a center flexure between the first and second beams, a first end flexure interconnected between an end of the first beam and the anchor, and a second end flexure interconnected between an end of the second beam and the movable element. Each of the end flexures includes the elongated beam having first and second ends, and the sidewall defining a longitudinal dimension of the elongated beam, and the protrusion element extending from the sidewall of the elongated beam, the protrusion element being displaced away from the first and second ends of the beam.

A MEMS inclinometer includes a substrate, a first mobile mass and a sensing unit. The sensing unit includes a second mobile mass, a number of elastic elements, which are interposed between the second mobile mass and the substrate and are compliant in a direction parallel to a first axis, and a number of elastic structures, each of which is interposed between the first and second mobile masses and is compliant in a direction parallel to the first axis and to a second axis. The sensing unit further includes a fixed electrode that is fixed with respect to the substrate and a mobile electrode fixed with respect to the second mobile mass, which form a variable capacitor.

Embodiments of multi-frequency excitation are described. In various embodiments, a natural frequency of a device may be determined. In turn, a first voltage amplitude and first fixed frequency of a first source of excitation can be selected for the device based on the natural frequency. Additionally, a second voltage amplitude of a second source of excitation can be selected for the device, and the first and second sources of excitation can be applied to the device. After applying the first and second sources of excitation, a frequency of the second source of excitation can be swept. Using the methods of multi-frequency excitation described herein, new operating frequencies, operating frequency ranges, resonance frequencies, resonance frequency ranges, and/or resonance responses can be achieved for devices and systems.

A multi-stage MEMS accelerometer is disclosed that includes a MEMS sensor that has two suspended structures (proof masses) suspended by suspension members. The suspended structures move together in response to input acceleration when less the acceleration is less than a threshold value. When the input acceleration is greater than the threshold value, one of the suspended structures makes contact with a mechanical stop while the other suspended structure continues to move with increased stiffness due to the combined stiffness of the suspension members. The contact with the mechanical stop contributes a nonlinear mechanical stiffening effect that counteracts the nonlinear capacitive effect inherent in capacitive based MEMS accelerometers. In some embodiments, more than two suspended structures can be used to allow for optimization of sensitivity for multiple full-scale ranges, and for higher fidelity tuning of mechanical sensitivity with nonlinear capacitance. In some embodiments, compliant mechanical stops are used.

A microelectromechanical (MEMS) accelerometer senses linear acceleration perpendicular to a MEMS device plane of the MEMS accelerometer based on a rotation of a proof mass out-of-plane about a rotational axis. A symmetry axis is perpendicular to the rotational axis. The proof mass includes a symmetric portion that is symmetric about the symmetry axis and that is contiguous with an asymmetric portion that is asymmetric about the symmetry axis.

A microelectromechanical system (MEMS) apparatus is described. The MEMS apparatus may comprise inertial sensors and energy harvesters configured to convert mechanical vibrational energy into electric energy. The harvested energy may be used to power an electronic circuit, such as the circuit used to sense acceleration from the inertial sensors. The inertial sensors and the energy harvesters may be disposed on the same substrate, and may share the same proof mass. The energy harvesters may include a piezoelectric material layers disposed on a flexible structure. When the flexible structures flexes in response to vibration, stress arises in the piezoelectric material layer, which leads to the generation of electricity. Examples of inertial sensors include accelerometers and gyroscopes.

A micromechanical z-inertial sensor having a movable MEMS structure developed in a second function layer; first spring elements developed in a first function layer, and a first electrode developed in the first function layer, the first spring elements being connected to the movable MEMS structure and to a substrate, and the first function layer being situated below the second function layer; second spring elements developed in a third function layer, and a second electrode developed in the third function layer, the second spring elements being connected to the movable MEMS structure and to the substrate, and the third function layer being disposed above the second function layer; the movable MEMS structure being deflectable in the z-direction with the aid of the spring elements, and in a defined manner, not being deflectable in the x- and y-directions.

The invention relates to an acceleration sensor (100) having a sensor material (120) which is mounted by means of spring elements (130) so as to be movable along a movement axis (x) over a substrate (110), first trim electrodes (140) which are connected to the sensor material (120), and second trim electrodes (150) which are connected to the substrate (110) and are associated with the first trim electrodes (140). When the sensor material is deflected along the movement axis, a spring force acting on the sensor material (120) is generated by the spring elements (130), and when the sensor material (120) is deflected, an electrostatic force acting on the sensor material (120), which counteracts the spring force, is generated by application of an electrical trim voltage between the first trim electrodes (140) and the second trim elements (150).

This disclosure reveals a resonator where at least one suspended inertial mass is driven into rotational oscillation by a piezoelectric drive transducer, or where the rotational motion of at least one suspended inertial mass is sensed by a piezoelectric sense transducer. The disclosure is based on the idea of suspending the inertial mass with a one-sided suspender arrangement, where only one suspender is attached to each anchor point, and on the optimal positioning of the suspender in relation to the effective center of gravity of the resonator. The resonator may be employed in a resonator system, a clock oscillator or a gyroscope.