A method of forming an ultrasonic transducer device includes forming and patterning a film stack over a substrate, the film stack comprising a metal electrode layer and a chemical mechanical polishing (CMP) stop layer formed over the metal electrode layer; forming an insulation layer over the patterned film stack; planarizing the insulation layer to the CMP stop layer; measuring a remaining thickness of the CMP stop layer; and forming a membrane support layer over the patterned film stack, wherein the membrane support layer is formed at thickness dependent upon the measured remaining thickness of the CMP stop layer, such that a combined thickness of the CMP stop layer and the membrane support layer corresponds to a desired transducer cavity depth.

The invention provides a MEMS microphone. The MEMS microphone includes a substrate, having a first opening. A dielectric layer is disposed on the substrate, wherein the dielectric layer has a second opening aligned to the first opening. A diaphragm is disposed within the second opening of the dielectric layer, wherein a peripheral region of the diaphragm is embedded into the dielectric layer at sidewall of the second opening. A backplate layer is disposed on the dielectric layer and covering over the second opening. The backplate layer includes a plurality of acoustic holes arranged into a regular array pattern. The regular array pattern comprises a pattern unit, the pattern unit comprises one of the acoustic holes as a center hole, and peripheral holes of the acoustic holes surrounding the center hole with a same pitch to the center hole.

A piezoelectric micromachined ultrasonic transducer (PMUT) includes a substrate, a stopper, and a membrane, where the substrate and the stopper are composed of same single-crystalline material. The substrate has a cavity penetrating the substrate, and the stopper protrudes from a top surface of the substrate and surrounds the edge of the cavity. The membrane is disposed over the cavity and attached to the stopper.

A method produces a micromechanical sensor element having a first electrode and a second electrode, wherein electrode wall surfaces of the first and the second electrodes are situated opposite one another in a first direction and form a capacitance, wherein one of the first electrode or the second electrode is movable in a second direction, in response to a variable to be detected, and a second one of the first electrode and the second electrode is fixed. The method includes producing a cavity in a semiconductor substrate, the cavity being closed by a doped semiconductor layer; producing the first and the second electrodes in the semiconductor layer, including modifying the electrode wall surface of the first electrode in order to have a smaller extent in the second direction than the electrode wall surface of the second electrode.

Various embodiments of the present disclosure are directed towards a semiconductor device. The semiconductor device includes an interconnect structure disposed over a semiconductor substrate. A dielectric structure is disposed over the interconnect structure. A plurality of cavities are disposed in the dielectric structure. A microelectromechanical system (MEMS) substrate is disposed over the dielectric structure, where the MEMS substrate comprises a plurality of movable membranes, and where the movable membranes overlie the cavities, respectively. A plurality of fluid communication channels are disposed in the dielectric structure, where each of the fluid communication channels extend laterally between two neighboring cavities of the cavities, such that each of the cavities are in fluid communication with one another.

A piezoelectric microelectromechanical systems device is provided, having a first piezoelectric layer, a first metal layer including a first metal, a second metal layer including a second metal, the first and second metals having different properties to compensate deflection due to thermal stress of any or all of the piezoelectric layer, the first metal layer, and second metal layer and a substrate including at least one wall defining a cavity and the at least one wall supporting the layers. The method for making the piezoelectric microelectromechanical systems device is also provided.

In an embodiment an electronic device includes a carrier board having an upper surface, an electronic chip mounted on the upper surface of the carrier board, the electronic chip having a mounting side facing the upper surface of the carrier board, a flexible mounting layer arranged between the upper surface of the carrier board and the mounting side of the electronic chip, the flexible mounting layer mounting the electronic chip to the carrier board, wherein the mounting side has at least one first region and a second region, and wherein the electronic chip has at least one chip contact element in the first region and at least one connection element arranged on the at least one first region and connecting the at least one chip contact element to the upper surface of the carrier board, wherein the flexible mounting layer separates the second region from the connection element.

This disclosure describes techniques of configuring capacitive comb fingers of an accelerometer resonator into discreet electrodes with drive electrodes and at least two sense electrodes. The routing of electrical signals is configured to produce parasitic feedthrough capacitances that are approximately equal. The sense electrodes may be placed on opposite sides of the moving resonator beams such that the changes in capacitance with respect to displacement (e.g. dC/dx) are approximately equal in magnitude and opposite in sign. The arrangement may result in sense currents that are also opposite in sign and result in feedthrough currents of the same sign. The sense outputs from the resonators may be connected to a differential amplifier, such that the difference in output currents may mitigate the effect of the feedthrough currents and cancel parasitic feedthrough capacitance. Parasitic feedthrough capacitance may cause increased accelerometer noise and reduced bias stability.

A MEMS actuator includes a monolithic body of semiconductor material, with a supporting portion of semiconductor material, orientable with respect to a first and second rotation axes, transverse to each other. A first frame of semiconductor material is coupled to the supporting portion through first deformable elements configured to control a rotation of the supporting portion about the first rotation axis. A second frame of semiconductor material is coupled to the first frame by second deformable elements, which are coupled between the first and the second frames and configured to control a rotation of the supporting portion about the second rotation axis. The first and second deformable elements carry respective piezoelectric actuation elements.

A self-calibration method for an accelerometer having a proof mass separated by a gap from a drive electrode and a sense electrode includes initializing the accelerometer to resonate, applying a first bias voltage to the sense electrode and a second bias voltage to the drive electrode to obtain a first scale factor, measuring a first acceleration over a first time interval, swapping the first bias voltage on the sense electrode with the second bias voltage previously on the drive electrode and the second bias voltage on the drive electrode with the first bias voltage previously on the sense electrode so that a bias voltage on the sense electrode is set to the second bias voltage and a bias voltage on the drive electrode is set to the second bias voltage to obtain a second scale factor, measuring a second acceleration over a second time interval, and calculating a true acceleration.