Abstract: A resonant member of a MEMS resonator oscillates in a mechanical resonance mode that produces non-uniform regional stresses such that a first level of mechanical stress in a first region of the resonant member is higher than a second level of mechanical stress in a second region of the resonant member. A plurality of openings within a surface of the resonant member are disposed more densely within the first region than the second region and at least partly filled with a compensating material that reduces temperature dependence of the resonant frequency corresponding to the mechanical resonance mode.

Abstract: A microelectromechanical system (MEMS) resonator includes a substrate having a substantially planar surface and a resonant member having sidewalls disposed in a nominally perpendicular orientation with respect to the planar surface. Impurity dopant is introduced via the sidewalls of the resonant member such that a non-uniform dopant concentration profile is established along axis extending between the sidewalls parallel to the substrate surface and exhibits a relative minimum concentration in a middle region of the axis.

Abstract: A semiconductor layer having an opening and a MEMS resonator formed in the opening is disposed between first and second substrates to encapsulate the MEMS resonator. An electrical contact that extends from the opening to an exterior of the MEMS device is formed at least in part within the semiconductor layer and at least in part within the first substrate.

Abstract: In a MEMS device having a substrate and a moveable micromachined member, a mechanical structure secures the moveable micromachined member to the substrate, thermally isolates the moveable micromachined member from the substrate and provides a conduction path to enable heating of the moveable micromachined member to a temperature of at least 300 degrees Celsius.

Abstract: Degenerately doped semiconductor materials are deployed within resonant structures to control the first and higher order temperature coefficients of frequency, thereby enabling temperature dependence to be engineered without need for cumulative material layers which tend to drive up cost and compromise resonator performance.

Abstract: The present inventions, in one aspect, are directed to micromachined resonator comprising: a first resonant structure extending along a first axis, wherein the first axis is different from a crystal axis of silicon, a second resonant structure extending along a second axis, wherein the second axis is different from the first axis and the crystal axis of silicon and wherein the first resonant structure is coupled to the second resonant structure, and wherein the first and second resonant structures are comprised of silicon (for example, substantially monocrystalline) and include an impurity dopant (for example, phosphorus) having a concentrations which is greater than 1019 cm?3, and preferably between 1019 cm?3 and 1021 cm?3.

Abstract: A micromachined apparatus includes micromachined thermistor having first and second ends physically and thermally coupled to a substrate via first and second anchor structures to enable a temperature-dependent resistance of the micromachined thermistor to vary according to a time-varying temperature of the substrate. The micromachined thermistor has a length, from the first end to the second end, greater than a linear distance between the first and second anchor structures.

Abstract: A microelectromechanical system (MEMS) resonator includes a resonant semiconductor structure, drive electrode, sense electrode and electrically conductive shielding structure. The first drive electrode generates a time-varying electrostatic force that causes the resonant semiconductor structure to resonate mechanically, and the first sense electrode generates a timing signal in response to the mechanical resonance of the resonant semiconductor structure. The electrically conductive shielding structure is disposed between the first drive electrode and the first sense electrode to shield the first sense electrode from electric field lines emanating from the first drive electrode.

Abstract: A resonant member of a MEMS resonator oscillates in a mechanical resonance mode that produces non-uniform regional stresses such that a first level of mechanical stress in a first region of the resonant member is higher than a second level of mechanical stress in a second region of the resonant member. A plurality of openings within a surface of the resonant member are disposed more densely within the first region than the second region and at least partly filled with a compensating material that reduces temperature dependence of the resonant frequency corresponding to the mechanical resonance mode.

Abstract: The temperature-dependent resistance of a MEMS structure is compared with an effective resistance of a switched CMOS capacitive element to implement a high performance temperature sensor.

Abstract: Phase-locked loop circuitry to generate an output signal, the phase-locked loop circuitry comprising oscillator circuitry, switched resistor loop filter, coupled to the input of the oscillator circuitry (which, in one embodiment, includes a voltage-controlled oscillator), including a switched resistor network including at least one resistor and at least one capacitor, wherein an effective resistance of the switched resistor network is responsive to and increases as a function of one or more pulsing properties of a control signal (wherein pulse width and frequency (or period) are pulsing properties of the control signal), phase detector circuitry, having an output which is coupled to the switched resistor loop filter, to generate the control signal (which may be periodic or non-periodic). The phase-locked loop circuitry may also include frequency detection circuitry to provide a lock condition of the phase-locked loop circuitry.

Abstract: A semiconductor layer having an opening and a MEMS resonator formed in the opening is disposed between first and second substrates to encapsulate the MEMS resonator. An electrical contact that extends from the opening to an exterior of the MEMS device is formed at least in part within the semiconductor layer and at least in part within the first substrate.

Abstract: A cavity is formed within a first substrate together with trenches that separate first and second portions of the first substrate from each other and from the remainder of the first substrate. The first portion of the first substrate is disposed within the cavity and constitutes a microelectromechanical structure, while the second portion of the substrate is disposed at least partly within the cavity and constitutes a first portion of an electrical contact. A second substrate is secured to the first substrate over the cavity to define a chamber containing the microelectromechanical structure. The second substrate has a first portion that constitutes a second portion of the electrical contact and is disposed in electrical contact with the second portion of the first substrate such that the electrical contact extends from within the chamber to an exterior of the chamber.

Abstract: A low-profile packaging structure for a microelectromechanical-system (MEMS) resonator system includes an electrical lead having internal and external electrical contact surfaces at respective first and second heights within a cross-sectional profile of the packaging structure and a die-mounting surface at an intermediate height between the first and second heights. A resonator-control chip is mounted to the die-mounting surface of the electrical lead such that at least a portion of the resonator-control chip is disposed between the first and second heights and wire-bonded to the internal electrical contact surface of the electrical lead.

Abstract: A MEMS resonator system that reduces interference signals arising from undesired capacitive coupling between different system elements. The system, in one embodiment, includes a MEMS resonator, electrodes, and at least one resonator electrode shield. In certain embodiments, the resonator electrode shield ensures that the resonator electrodes interact with either one or more shunting nodes or the active elements of the MEMS resonator by preventing or reducing, among other things, capacitive coupling between the resonator electrodes and the support and auxiliary elements of the MEMS resonator structure. By reducing the deleterious effects of interfering signals using one or more resonator electrode shields, a simpler, lower interference, and more efficient system relative to prior art approaches is presented.

Abstract: Phase-locked loop circuitry to generate an output signal, the phase-locked loop circuitry comprising oscillator circuitry, switched resistor loop filter, coupled to the input of the oscillator circuitry (which, in one embodiment, includes a voltage-controlled oscillator), including a switched resistor network including at least one resistor and at least one capacitor, wherein an effective resistance of the switched resistor network is responsive to and increases as a function of one or more pulsing properties of a control signal (wherein pulse width and frequency (or period) are pulsing properties of the control signal), phase detector circuitry, having an output which is coupled to the switched resistor loop filter, to generate the control signal (which may be periodic or non-periodic). The phase-locked loop circuitry may also include frequency detection circuitry to provide a lock condition of the phase-locked loop circuitry.

Abstract: A temperature to digital converter circuitry to generate output data which is representative of one or more temperature dependent characteristics of a temperature sensitive device (for example, MEMS thermistor having a resistance that correlates to its temperature), the temperature to digital circuitry comprising a switched capacitor network to generate a effective reference resistance in response to a switching signal, a signal generator to generate the switching signal, wherein the switching signal has a switching frequency which is controlled, at least in part, via control data, comparator circuitry to generate error data using the effective reference resistance and the resistance of the temperature sensitive device, and converter circuitry to generate the output data which is representative of one or more temperature dependent characteristics of the temperature sensitive device.

Abstract: In a microelectromechanical system (MEMS) resonator having a reduced magnitude of thermal coefficient of frequency (TCF), a resonant member has first and second surfaces and an opening in the first surface that extends toward the second surface. A compensating material is disposed within the opening and characterized by a temperature coefficient of Young's Modulus (TCE) having a sign opposite that of a TCE of the resonant member.

Abstract: The present inventions, in one aspect, are directed to a temperature sensing apparatus comprising a micromachined thermistor configured to output voltage and/or current signals which are/is correlated to an ambient temperature. The micromachined thermistor includes a micromachined thermistor structure suspended over and released from the substrate, wherein the micromachined thermistor structure includes a temperature dependent characteristic (e.g., resistance to an electrical current), and electrical contacts connected to the micromachined thermistor structure, wherein the electrical contacts are adapted to conduct the voltage and/or current signals. The apparatus, in one aspect, includes measurement circuitry, to generate data which is representative of the ambient temperature using the electrical resistance of the micromachined thermistor structure.

Abstract: In a packaging structure for a microelectromechanical-system (MEMS) resonator system, a resonator-control chip is mounted on a lead frame having a plurality of electrical leads, including electrically coupling a first contact on a first surface of the resonator-control chip to a mounting surface of a first electrical lead of the plurality of electrical leads through a first electrically conductive bump. A MEMS resonator chip is mounted to the first surface of the resonator-control chip, including electrically coupling a contact on a first surface of the MEMS resonator chip to a second contact on the first surface of the resonator-control chip through a second electrically conductive bump. The MEMS resonator chip, resonator-control chip and mounting surface of the first electrical lead are enclosed within a package enclosure that exposes a contact surface of the first electrical lead at an external surface of the packaging structure.