This piezoelectric wafer has: a piezoelectric vibration piece; a frame portion that supports the piezoelectric vibration piece; and a coupling portion that couples the piezoelectric vibration piece to the frame portion. The piezoelectric vibration piece is broken off at the coupling portion and separated from the piezoelectric wafer. On front and back surfaces of the coupling portion, grooved slits extending along a width direction of the coupling portion are formed except for parts of the coupling portion in the width direction. An electrode on at least one of front and back surfaces of the piezoelectric vibration piece is extracted to a frame-portion side of the piezoelectric wafer by way of the part of the coupling portion in the width direction.

A MEMS resonator includes a main substrate forming a receiving part at a center of the main substrate; a mass body having one end part and a center part elastically supported by both sides of the main substrate; a driving unit configured at one side of the receiving part on the main substrate and producing a driving force by a voltage applied to both sides of the one end part of the mass body to move a position of the mass body with respect to the main substrate; and a tuning part including a pair of tuning units provided symmetrically with respect to the second elastic member, and having a beam member changing a length of the second elastic member by an actuating operation of each tuning unit to control a frequency.

A mechanical resonator includes a spring-mass system, wherein the spring-mass system comprises a phase-change material. The mechanical resonator typically comprises an electrical circuit portion, coupled to the phase-change material to alter a phase configuration within the phase-change material. Methods of operation are also disclosed.

A dual resonator chip, includes a kilohertz frequency resonator in the chip and a megahertz frequency resonator in the same chip, wherein the kilohertz frequency resonator and the megahertz frequency resonator are MEMS resonators.

A resonator including a vibrating portion with first and second electrodes and a piezoelectric film formed therebetween. Moreover, a frame surrounds the vibrating portion with a pair of holding units opposite to each other and connecting the vibrating portion with the frame. An extended electrode extends from the holder to the holding unit and either the first or second electrode extends to the holding unit, and is connected to the extended electrode. Furthermore, the resonator includes an electrical resistance value per unit area of the extended electrode that is smaller than an electrical resistance value per unit area of the first electrode or the second electrode that extends to the holding unit.

A mechanical resonator includes a spring-mass system, wherein the spring-mass system comprises a phase-change material. The mechanical resonator typically comprises an electrical circuit portion, coupled to the phase-change material to alter a phase configuration within the phase-change material. Methods of operation are also disclosed.

A MEMS/NEMS device having an adjustable frequency response comprises an array of electrostatically actuated resonators, an electrostatic actuation circuit, electrical detection means, and means adjusting the frequency response of the resonators. The device comprises resonators having a movable portion, electrically connected in series between a first biasing potential V.sub.B and a second biasing potential V.sub.B2, each resonator biased to a potential Vi between V.sub.B and V.sub.B2, depending on position in the series. The electrostatic actuation circuit comprises, for each resonator, an actuation electrode facing the movable portion, all electrodes being connected in parallel to a common control potential V.sub.IN, the actuation voltage of each resonator being equal to V.sub.INVi. The detection means comprises a detection output common to all resonators, the output being connected to an output potential V.sub.out. The means for adjusting the frequency response varies the common control potential and/or at least one of the biasing potentials.

A MEMS resonator includes a main substrate forming a receiving part at a center of the main substrate; a mass body having one end part and a center part elastically supported by both sides of the main substrate; a driving unit configured at one side of the receiving part on the main substrate and producing a driving torque by a voltage applied to both sides of the one end part of the mass body to move a position of the mass body with respect to the main substrate; and a tuning part including a pair of tuning units provided symmetrically with respect to the second elastic member, and having a beam member changing a length of the second elastic member by an actuating operation of each tuning unit to control a frequency.

A mechanical resonator includes a spring-mass system, wherein the spring-mass system comprises a phase-change material. The mechanical resonator typically comprises an electrical circuit portion, coupled to the phase-change material to alter a phase configuration within the phase-change material. Methods of operation are also disclosed.

A resonator drive method is provided. The resonator drive method comprises: driving a third electrode that is higher than the first electrode and the second electrode based on an upper surface of the substrate, which are spaced apart from each other at a first interval on a substrate, to descend toward the substrate; and arranging the third electrode between the first electrode and the second electrode to be in contact with the upper surface of the substrate and arranging the first electrode, the second electrode, and the third electrode to be spaced apart from one another at a second interval, wherein the second interval is less than the first interval.