Abstract: Micromachined devices and methods for making the devices. The device includes: a first wafer having at least one via; and a second wafer having a micro-electromechanical-systems (MEMS) layer. The first wafer is bonded to the second wafer. The via forms a closed loop when viewed in a direction normal to the top surface of the first wafer to thereby define an island electrically isolated. The method for fabricating the device includes: providing a first wafer having at least one via; bonding a second wafer having a substantially uniform thickness to the first wafer; and etching the bonded second wafer to form a micro-electromechanical-systems (MEMS) layer.

Abstract: Micromachined gyroscope having a pair of masses disposed generally in a plane and driven for out-of-plane torsional oscillation about a pair of drive axes in the plane for sensing rotation about an input axis perpendicular to the drive axes. The masses are mounted for in-plane torsional movement about sense axes perpendicular to the drive axes and the input axis in response to Coriolis forces produced by rotation of the masses about the input axis. A link connects the two masses together for movement of equal amplitude and opposite phase both about the drive axes and about the sense axes. The masses are connected to transducers having input electrodes constrained for linear in-plane movement relative to stationary electrodes, with that torsional movement of the masses about the sense axes producing changes in capacitance between the input electrodes and the stationary electrodes.

Abstract: Integrated micromachined inertial sensing unit with multi-axis angular rate and acceleration sensors and method of fabricating the same. Micromachined angular rate and acceleration sensors are integrated together with an application-specific integrated circuit (ASIC) in one compact package. The ASIC combines many separate functions required to operate multiple rate sensors and accelerometers into a single chip. The MEMS sensing elements and the ASIC are die-stacked, and electrically connected either directly using ball-grid-arrays or wirebonding. Through the use of a single package and single ASIC for multiple angular rate and acceleration sensors, significant reduction in cost is achieved.

Abstract: A method of operating an anti-phase six degree-of-freedom tuning fork gyroscope system comprises the steps of driving a first three degree-of-freedom gyroscope subsystem, and driving a second three degree-of freedom gyroscope subsystem in an anti-phase mode with the first gyroscope subsystem at an anti-phase resonant frequency. Acceleration or an angular rate of motion is sensed by means of the first and second three degree-of-freedom gyroscope subsystems operating in a flat frequency response range where the anti-phase resonant frequency is designed. Response gain and phase are stable and environmental and fabrication perturbations are avoided by such operation. A anti-phase six degree-of-freedom tuning fork gyroscope system which operates as described is also characterized.

Abstract: Micromachined accelerometer and method in which a proof mass is suspended above a substrate for movement in response to acceleration, electrodes form capacitors which change in capacitance in response to movement of the proof mass, processing circuitry responsive to the changes in capacitance provides an output signal corresponding to movement of the proof mass, a test signal is applied to the electrodes during use of the accelerometer to produce additional movement of the proof mass and a corresponding test signal component in the output signal, and the output signal is monitored to determine whether the accelerometer is operating normally by the presence of the test signal component in the output signal.

Abstract: Micromachined accelerometer having one or more proof masses (16, 36, 37, 71, 72) mounted on one or more decoupling frames (17, 38, 39) or on a shuttle (73) such that the proof mass(es) can move along a first (y) axis in response to acceleration along the first axis while being constrained against movement along a second (x) axis and for torsional movement about a third (z) axis perpendicular to the first and second axes in response to acceleration along the second axis. Electrodes (26, 53, 54, 78, 79) that move with the proof mass(es) are interleaved with stationary electrodes (27, 56, 57, 81, 82) to form capacitors (A-D) that change in capacitance both in response to movement of the proof mass(es) along the first axis and in response to torsional movement of the proof mass(es) about the third axis, and circuitry (31-34) connected to the electrodes for providing output signals corresponding to acceleration along the first and second axes.

Abstract: Angular rate sensor for detecting rotation about first and second mutually perpendicular axes which has first and second masses coupled together for torsional drive mode oscillation of equal amplitude and opposite phase about third axes which are perpendicular to the first and second axes. The first mass is mounted for oscillation about the second axis in response to Coriolis forces produced by rotation about the first axis, and the second mass is mounted for oscillation about the first axis in response to Coriolis forces produced by rotation about the second axis. In some disclosed embodiments, the rate sensor also includes a pair of accelerometer masses which are connected together for torsional movement of equal amplitude and opposite phase about axes parallel to the third axes in response to acceleration along the second axis and for torsional movement of equal amplitude and opposite phase about axes parallel to the second axis in response to acceleration along the third axes.

Abstract: A gimbal-type torsional z-axis micromachined gyroscope with a non-resonant actuation scheme measures angular rate of an object with respect to the axis normal to the substrate plane (the z-axis). A 2 degrees-of-freedom (2-DOF) drive-mode oscillator is comprised of a sensing plate suspended inside two gimbals. By utilizing dynamic amplification of torsional oscillations in the drive-mode instead of resonance, large oscillation amplitudes of the sensing element is achieved with small actuation amplitudes, providing improved linearity and stability despite parallel-plate actuation. The device operates at resonance in the sense direction for improved sensitivity, while the drive direction amplitude is inherently constant within the same frequency band.

Abstract: A four-degrees-of-freedom (DOF) nonresonant micromachined gyroscope utilizes a dynamical amplification both in the drive-direction oscillator and the sense-direction oscillator, which are structurally decoupled, to achieve large oscillation amplitudes without resonance. The overall dynamical system is comprised of three proof masses. The second and third masses form the sense-direction oscillator. The first mass and the combination of the second and third masses form the drive-direction oscillator. The frequency responses of the drive and sense-mode oscillators have two resonant peaks and a flat region between the peaks. The device is nominally operated in the flat regions of the response curves belonging to the drive and sense-mode oscillators, where the gain is less sensitive to frequency fluctuations. This is achieved by designing the drive and sense anti-resonance frequencies to match.

Abstract: Angular rate sensor for detecting rotation about first and second mutually perpendicular axes which has first and second masses coupled together for torsional drive mode oscillation of equal amplitude and opposite phase about third axes which are perpendicular to the first and second axes. The first mass is mounted for oscillation about the second axis in response to Coriolis forces produced by rotation about the first axis, and the second mass is mounted for oscillation about the first axis in response to Coriolis forces produced by rotation about the second axis. In some disclosed embodiments, the rate sensor also includes a pair of accelerometer masses which are connected together for torsional movement of equal amplitude and opposite phase about axes parallel to the third axes in response to acceleration along the second axis and for torsional movement of equal amplitude and opposite phase about axes parallel to the second axis in response to acceleration along the third axes.

Abstract: A three-degrees of freedom (DOF) MEMS inertial micromachined gyroscope with nonresonant actuation with a drive direction, sense direction and a direction perpendicular to the drive and sense directions comprises a planar substrate, a 2-DOF sense-mode oscillator coupled to the substrate operated at a flattened wide-bandwidth frequency region, and a 1-DOF drive mode oscillator coupled operated at resonance in the flattened wide-bandwidth frequency region to achieve large drive-mode amplitudes.

Abstract: A MEMS device which utilizes a capacitive sensor or actuator is enhancement by initially fabricating the capacitive assembly which comprises the sensor or actuator as two sets of interdigitated fingers in a noninterdigitated configuration. One of the two sets of fingers is coupled to a movable stage. The stage is moved from an initial position to a post-release position in which the two sets of interdigitated fingers are interdigitated with each other. The stage is carried by two pairs flexures which maintain the stability of motion of the stage and when in the post-release position provide stiffness which prevents deflection of the set of fingers coupled to the stage. The stage and hence the assembled sets of fingers are then locked into the post-release position.

Abstract: Multi-axis micromachined accelerometer and rate sensor having first and second generally planar masses disposed side-by-side and connected together along adjacent edge portions thereof for torsional movement about axes parallel to a first axis in response to acceleration along a second axis and for rotational motion about axes parallel to the second axis in response to acceleration along the first axis. The masses are driven to oscillate about the axes parallel to the second axis so that Coriolis forces produced by rotation about a third axis result in torsional movement of the masses about the axes parallel to the first axis. Sensors monitor the movement of the mass about the axes, and signals from the sensors are processed to provide output signals corresponding to acceleration along the first and second axes and rotation about the third axis.

Abstract: Rate sensor having a plurality of generally planar masses, a drive axis in the planes of the masses, an input axis perpendicular to the drive axis, and sense axes perpendicular to the drive axis and the input axis. The masses are driven to oscillate about drive axes and are mounted for torsional movement about the sense axes in response to Coriolis forces produced by rotation of the messes about the input axis, with sensors responsive to the torsional movement about the sense axis for monitoring rate of rotation.

Abstract: Rate sensor having a plurality of generally planar masses, a drive axis in the plane of each of the masses, an input axis perpendicular to the drive axes, and sense axes perpendicular to the drive axes and the input axis. The masses are driven to oscillate about the drive axes and are mounted for torsional movement about the sense axes in response to Coriolis forces produced by rotation of the masses about the input axis, with sensors responsive to the torsional movement about the sense axis for monitoring rate of rotation.

Abstract: Rate sensor having a plurality of generally planar masses, a drive axis in the planes of the masses, an input axis perpendicular to the drive axis, and sense axes perpendicular to the drive axis and the input axis. The masses are driven to oscillate about the drive axes and are mounted for torsional movement about the sense axes in response to Coriolis forces produced by rotation of the masses about the input axis, with sensors responsive to the torsional movement about the sense axis for monitoring rate of rotation.

Abstract: Multi-axis micromachined accelerometer which, in some disclosed embodiments, has a proof mass suspended above a substrate for movement in response to acceleration along first and second axes, a first detection electrode connected to the proof mass and constrained for movement only along the first axis, and a second detection electrode connected to the proof mass and constrained for movement only along the second axis. In another embodiment, the proof mass is also movable in response to acceleration along a third axis which is perpendicular to the substrate, and a third detection electrode is mounted on the substrate beneath the proof mass for detecting movement of the proof mass in response to acceleration along the third axis.

Abstract: A three-degrees of freedom (DOF) MEMS inertial micromachined gyroscope with nonresonant actuation with a drive direction, sense direction and a direction perpendicular to the drive and sense directions comprises a planar substrate, a 2-DOF sense-mode oscillator coupled to the substrate operated at a flattened wide-bandwidth frequency region, and a 1-DOF drive mode oscillator coupled operated at resonance in the flattened wide-bandwidth frequency region to achieve large drive-mode amplitudes.

Abstract: Rate sensor comprising two generally planar proof masses, means for driving the masses to oscillate in phase opposition about parallel drive axes in the planes of the masses, an input axis perpendicular to the drive axes, sense axes perpendicular to the drive axes and the input axis, means mounting the masses for torsional movement about the sense axes in response to Coriolis forces produced by rotation of the masses about the input axis, means constraining the two masses for anti-phase movement about both the drive axes and the sense axes, sensing frames coupled to the masses for movement in response to the torsional movement of the masses about the sense axes, and means responsive to movement of the sensing frames for monitoring rate of rotation about the input axis.

Abstract: Rate sensor having a plurality of generally planar masses, means for driving the masses to oscillate about a drive axis in the planes of the masses, an input axis perpendicular to the drive axis, sense axes perpendicular to the drive axis and the input axis, means mounting the masses for torsional movement about the sense axes in response to Coriolis forces produced by rotation of the masses about the input axis, and means responsive to the torsional movement about the sense axis for monitoring rate of rotation about the input axis.