Microelectromechanical system (MEMS) inertial sensors exhibiting reduced parasitic capacitance are described. The reduction in the parasitic capacitance may be achieved by forming localized regions of thick dielectric material. These localized regions may be formed inside trenches. Formation of trenches enables an increase in the vertical separation between a sense capacitor and the substrate, thereby reducing the parasitic capacitance in this region. The stationary electrode of the sense capacitor may be placed between the proof mass and the trench. The trench may be filled with a dielectric material. Part of the trench may be filled with air, in some circumstances, thereby further reducing the parasitic capacitance. These MEMS inertial sensors may serve, among other types of inertial sensors, as accelerometers and/or gyroscopes. Fabrication of these trenches may involve lateral oxidation, whereby columns of semiconductor material are oxidized.

A sensor package comprising: a sensor, wherein the sensor comprises a sensing structure formed in a material layer and one or more further material layers arranged to seal the sensing structure to form a hermetically sealed sensor unit; a support structure; one or more springs flexibly fixing the hermetically sealed sensor unit to the support structure; wherein the one or more springs are formed in the same material layer as the sensing structure of the sensor unit; and one or more external package wall(s) encapsulating the sensor unit, the support structure, and the one or more springs, wherein the support structure is fixed to at least one of the package wall(s). The springs decouple mechanical stresses between the sensor unit and the external package wall(s) so as to reduce the long term drift of scale factor and bias.

The MEMS gyroscope has a mobile mass carried by a supporting structure to move in a driving direction and in a first sensing direction, perpendicular to each other. A driving structure governs movement of the mobile mass in the driving direction at a driving frequency. A movement sensing structure is coupled to the mobile mass and detects the movement of the mobile mass in the sensing direction. A quadrature-injection structure is coupled to the mobile mass and causes a first and a second movement of the mobile mass in the sensing direction in a first calibration half-period and, respectively, a second calibration half-period. The movement-sensing structure supplies a sensing signal having an amplitude switching between a first and a second value that depend upon the movement of the mobile mass as a result of an external angular velocity and of the first and second quadrature movements. The first and second values of the sensing signal are subtracted from each other and compared with a stored difference value to supply information of variation of the scale factor.

An exemplary microelectromechanical device includes a MEMS layer, portions of which respond to an external force in order to measure the external force. A substrate layer is located below the MEMS layer and an anchor couples the substrate layer and MEMS layer to each other. A plurality of temperature sensors are located within the substrate layer to identify a temperature gradient being experienced by the MEMS device. Compensation is performed or operations of the MEMS device are modified based on temperature gradient.

A sensor including one or more transistors; and one or more sensing elements, wherein an edge behaves as moving gate of said one or more transistors, an electric field is applied to said edge, said one or more transistors is/are biased, said one or more sensing elements is/are flexible, source and drain wells of said one or more transistors can be coplanar or stacked, said edge can move in a lateral or a parallel direction with respect to a transistor current, said edge can move in a vertical or a perpendicular direction with respect to said transistor current, and the magnitude of the change in said drain current determines the sensitivity.

A micro-electromechanical-system (MEMS) device may be formed to include an anti-stiction polysilicon layer on one or more moveable MEMS structures of a device wafer of the MEMS device to reduce, minimize, and/or eliminate stiction between the moveable MEMS structures and other components or structures of the MEMS device. The anti-stiction polysilicon layer may be formed such that a surface roughness of the anti-stiction polysilicon layer is greater than the surface roughness of a bonding polysilicon layer on the surfaces of the device wafer that are to be bonded to a circuitry wafer of the MEMS device. The higher surface roughness of the anti-stiction polysilicon layer may reduce the surface area of the bottom of the moveable MEMS structures, which may reduce the likelihood that the one or more moveable MEMS structures will become stuck to the other components or structures.

A MEMS sensor includes a proof mass that is suspended over a substrate. A sense electrode is located on a top surface of the substrate parallel to the proof mass, and forms a capacitor with the proof mass. The sense electrodes have a plurality of slots that provide improved performance for the MEMS sensor. A measured value sensed by the MEMS sensor is determined based on the movement of the proof mass relative to the slotted sense electrode.

A modification to rough polysilicon using ion implantation and silicide is provided herein. A method can comprise depositing a hard mask on a single crystal silicon, patterning the hard mask, and depositing metal on the single crystal silicon. The method also can comprise forming silicide based on causing the metal to react with exposed silicon of the single crystal silicon. Further, the method can comprise removing unreacted metal and stripping the hard mask from the single crystal silicon. Another method can comprise forming a MEMS layer based on fusion bonding a handle MEMS with a device layer. The method also can comprise implanting rough polysilicon on the device layer. Implanting the rough polysilicon can comprise performing ion implantation of the rough polysilicon. Further, the method can comprise performing high temperature annealing. The high temperature can comprise a temperature in a range between around 700 and 1100 degrees Celsius.

A method includes forming an etch stop layer over a first side of a device wafer. The method also includes forming a polysilicon layer over the etch stop layer. A handle wafer is fusion bonded to the first side of the device wafer. A eutectic bond layer is formed on a second side of the device wafer. A micro-electro-mechanical system (MEMS) features are etched into the second side of the device wafer to expose the etch stop layer. The exposed etch stop layer is removed to expose the polysilicon layer. The exposed polysilicon layer is removed to expose a cavity formed between the handle wafer and the device wafer.

Techniques relating to a micro-electro-mechanical (MEMS) device configured to measure direct axial and shear stress components of a stress tensor are described. The MEMS device includes a first and second circuit configured in a double rosette structure coupled with a third circuit in a standard rosette structure to form a triple rosette piezo-resistive gauge circuit. The first circuit includes at least one piezoresistive element suspended from a substrate, and at least one piezoresistive element fixed to the substrate. The second circuit includes each piezoresistive element fixed to the substrate. The third circuit includes at least one piezoresistive element fixed to the substrate. Additionally, the MEMS device may be coupled to one or more processing systems to determine a mechanical stress tensor that is applied to the MEMS device based on measurements received from the MEMS device.