A MEMS device may include: (i) a lower cavity, including a first island, formed within a first layer of the MEMS device; (ii) an upper cavity, including a second island, formed within a second layer of the MEMS device; (iii) a MEMS resonating element arranged in a device layer of the MEMS device and anchored via the first and second islands; (iv) a first set of electrodes for electrostatic actuation and sensing of the MEMS resonating element in an in-plane mode that is arranged in the device layer of the MEMS device; and (v) a second set of electrodes for electrostatic actuation and sensing of the MEMS resonating element in an out-of-plane mode that is electrically isolated from the first set of electrodes and located in the first or second layer of the MEMS device, and wherein the out-of-plane mode is a torsional mode or a saddle mode.

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.

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.

A resonator is provided that includes a vibration member that includes a substrate, a metal layer formed along one of main surfaces of the substrate, and a piezoelectric thin film disposed between the substrate and the metal layer. The vibration member vibrates such that a main vibration is a contour vibration. Moreover, a frame surrounds at least a portion of the vibration member, and a support unit connects the vibration member to the frame. The vibration member includes depressed portions on or above the one of main surfaces where the piezoelectric thin film is removed.

A resonance device that includes a MEMS substrate including a resonator, an upper cover, and a bonding portion that bonds the MEMS substrate to the upper cover to seal a vibration space of the resonator. The bonding portion includes a eutectic layer composed of a eutectic alloy of germanium and a metal mainly containing aluminum, a first titanium (Ti) layer, a first aluminum oxide film, and a first conductive layer consecutively arranged from the MEMS substrate to the upper cover.

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.

A resonator is provided that includes a vibrating portion including three or more vibrating arms with at least two vibrating arms that bend out of plane with different phases and a base. The resonator also includes a frame that holds the vibrating portion; and a support arm having one end connected to the frame and the other end connected to a rear end portion of the base. The other end of the support arm is connected to a position in a range from −0.1 WB to 0.1 WB, with respect to a base width WB of the base, relative to a position, on the rear end portion of the base where a center line passes in a plan view. A support arm length of the support arm is 0.2 or more times and 0.4 or less times a vibrating arm length of the vibrating arms.

A method of forming a resonator includes forming top and bottom dielectric structures over a substrate. A piezoelectric layer is formed between the top and bottom dielectric structures. A bottom electrode is formed between the piezoelectric layer and the bottom dielectric structure, and a top electrode is formed between the piezoelectric layer and the top dielectric structure. A metal layer is formed over the top dielectric structure and is patterned, thereby forming a first contact pad making electrical contact to the top electrode, a second contact pad making electrical contact with the bottom electrode, and a mass bias located over the top dielectric structure.

A micromechanical resonator wafer assembly includes an actuator wafer supporting an outer actuator layer. The outer actuator layer includes an oscillating part configured to be driven by an electrical drive signal. The micromechanical resonator wafer assembly further includes a device wafer mounted on top of the actuator wafer. The device wafer includes a plurality of inner actuators. Each of the inner actuators include an oscillation body configured to oscillate about one or more axes. The device wafer is physically connected to the actuator wafer such that each of the inner actuators forms with the outer actuator layer a coupled oscillation system for excitation of the oscillation body of the respective inner actuator. The micromechanical resonator wafer assembly provides external actuation of the oscillation body of each of the inner actuators by use of the outer actuator layer and hence, provides improved scan angles with fast start-up time.