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.

A temperature-compensated microelectromechanical oscillator and a method of fabricating thereof. The oscillator includes a resonator element including highly doped silicon and an actuator for exciting the resonator body into a resonance mode having a characteristic frequency-vs-temperature curve. The properties of the resonator element and the actuator are chosen such that the curve has a high-temperature turnover point at a turnover temperature of 85° C. or more. In addition, the oscillator comprises a thermostatic controller for keeping the temperature of the resonator element at said high turnover temperature.

A resonance device is provided that includes a resonator having a base, a vibrating arm extending from one end of the base along a first direction, a frame disposed around at least a part of the vibrating arm and holding the vibrating arm such that the vibrating arm is configured to vibrate, and a support arm connecting the base to the frame. Moreover, a first substrate is provided that includes a first recess forming at least a part of a vibration space for the resonator and a first limiting portion provided away from the support arm by a first distance in a thickness direction, in which the first distance is smaller than a distance between a bottom surface of the first recess and the vibrating arm in the thickness direction of the first substrate.

A moveable micromachined member of a microelectromechanical system (MEMS) device includes an insulating layer disposed between first and second electrically conductive layers. First and second mechanical structures secure the moveable micromachined member to a substrate of the MEMS device and include respective first and second electrical interconnect layers coupled in series, with the first electrically conductive layer of the moveable micromachined member and each other, between first and second electrical terminals to enable conduction of a first joule-heating current from the first electrical terminal to the second electrical terminal through the first electrically conductive layer of the moveable micromachined member.

An acoustic resonator includes a piezoelectric stack including a piezoelectric layer having a top surface and a bottom surface, a top electrode layer disposed above the top surface, and a bottom electrode layer disposed below the bottom surface. A number of acoustic wave reflectors are disposed on a side of the bottom electrode layer opposite the piezoelectric layer. Each acoustic wave reflector includes a high acoustic impedance layer and may include a low acoustic impedance layer. The acoustic resonator may include a tether that extends laterally to a stacking direction of the layers of the piezoelectric stack. A supporting structure may be coupled to the tether opposite the acoustic resonator for anchoring the acoustic resonator. A mirror, one or more phononic crystals, or both may be positioned on proximate the tether opposite the acoustic resonator to avoid resonant waves from exiting the acoustic resonator in use.

A resonance device includes a resonator, an upper lid, and a lower lid. The resonator includes a vibration portion, a frame, and holding arms. The vibration portion includes a base and a plurality of vibration arms. The lower lid has a protruding portion protruding between two adjacent vibration arms, the protruding portion has an insulating film, the vibration arms have a weight portion that has a conductive film formed on the insulating film, and in a direction in which the plurality of vibration arms extend, a first distance between the weight portion of any one of the two adjacent vibration arms and the holding portion is less than a second distance between the weight portion and the protruding portion.

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 10.sup.19 cm.sup.-3, and preferably between 10.sup.19 cm.sup.-3 and 10.sup.21 cm.sup.-3.

A temperature-controlled RF resonator. The resonator includes an insulating thermal enclosure within which are implemented: at least one resonant element configured to deliver an RF output signal when supplied with an RF input signal; at least one heating element configured to supply thermal energy within the thermal enclosure when the at least one heating element is powered by an LF electric power signal; and at least one temperature sensor configured to deliver an LF electric measurement signal as a function of the temperature inside the thermal enclosure. Such an RF resonator has at least one input/output port crossing the insulating thermal enclosure and propagating at least: one signal from among the RF signals; and another signal from among the LF electric signals.

A moveable micromachined member of a microelectromechanical system (MEMS) device includes an insulating layer disposed between first and second electrically conductive layers. First and second mechanical structures secure the moveable micromachined member to a substrate of the MEMS device and include respective first and second electrical interconnect layers coupled in series, with the first electrically conductive layer of the moveable micromachined member and each other, between first and second electrical terminals to enable conduction of a first joule-heating current from the first electrical terminal to the second electrical terminal through the first electrically conductive layer of the moveable micromachined member.

A dual-output microelectromechanical system (MEMS) resonator can be operated selectively and concurrently in an in-plane mode of vibration and an out-of-plane mode of vibration to obtain, respectively, a first electrical signal having a first frequency and a second electrical signal having a second frequency that is less than the first frequency. The first and second electrical signals are mixed to obtain a third electrical signal having a third frequency, where the third frequency is proportional to a temperature of the MEMS resonator. The temperature is determined based on the third frequency. Values of the first and second frequencies can be adjusted based on the determined temperature to compensate for frequency deviations due to temperature deviations. Also described herein are methods and systems for determining the temperature of the dual-output MEMS and for performing frequency compensation, as well as a method of manufacturing the dual-output MEMS.