A gallium nitride structure that includes: a substrate; a gallium nitride layer opposed to the substrate and containing gallium nitride as a main component thereof; and a first electrode between the gallium nitride layer and the substrate. The first electrode includes at least one hafnium layer containing a single metal of hafnium as a main component thereof, and the at least one hafnium layer is in contact with the gallium nitride layer.

A logic system includes a microelectromechanical system, MEMS, resonator having an arch beam and first and second side beams, wherein the first side beam is attached with a first end to a first end of the arch beam and the second side beam is attached with a first end to a second end of the arch beam to form a U-shape; an input electrode facing the second side beam; a selector electrode facing the second side beam; a first output electrode facing the first side beam; and a second output electrode facing the arch beam.

A resonator includes a base, at least one vibration arm, a frame, and a holding arm. The vibration arm includes a piezoelectric film, an upper electrode, and a lower electrode. The inequality Fs/Fm<1.9 or the inequality 2.1<Fs/Fm holds, where Fm is a frequency of a main or primary mode in the vibration arm, and Fs is a frequency of a spurious mode in the holding arm.

A resonator is provided that includes a vibration part and a mass addition portion. The vibration part includes a piezoelectric film, an upper electrode, and a lower electrode. The upper electrode and the lower electrode are disposed on opposite sides with the piezoelectric film therebetween. The amount of displacement of the vibration part is greater in a region corresponding to at least part of the mass addition portion than in any other region. The mass addition portion has an inclined surface that slopes in such a manner that the mass addition portion has end regions and a central region thinner than at least one of the end regions when the vibration part is viewed in a plan view.

A method for generating high order harmonic frequencies includes: providing a piezoelectric resonant film; and inputting a driving signal with a single tone frequency for driving the piezoelectric resonant film to oscillate in a non-linear region so as to generate a plurality of high order harmonic frequencies. Therefore, the quantity of the high order harmonic frequencies can be adjusted by applying an electrical controlling method.

A method of an open loop characterization of an electrostatic MEMS based resonator with a varying gap, the method including: converting, via a trans-impedance amplifier circuit, an output current signal of the resonator into a voltage; multiplying the output current signal converted into the voltage, by means of a multiplier circuit, with an AC signal or with a different signal at a frequency of the resonator and carrying a second harmonic signal to a main tone; and measuring a frequency response of a signal cleared of frequencies apart from the main tone using a network analyzer.

Describe is a resonator that uses ferroelectric (FE) materials in the gate of a transistor as a dielectric. The use of FE increases the strain/stress generated in the gate of the FinFET. Along with the usual capacitive drive, which is boosted with the increased polarization, FE material expands or contacts depending on the applied electric field on the gate of the transistor. As such, acoustic waves are generated by switching polarization of the FE materials. In some embodiments, the acoustic mode of the resonator is isolated using phononic gratings all around the resonator using the metal line above and vias' to body and dummy fins on the side. As such, a Bragg reflector is formed above the FE based transistor.

Describe is a resonator that uses anti-ferroelectric (AFE) materials in the gate of a transistor as a dielectric. The use of AFE increases the strain/stress generated in the gate of the FinFET. Along with the usual capacitive drive, which is boosted with the increased polarization, additional current drive is also achieved from the piezoelectric response generated to due to AFE material. In some embodiments, the acoustic mode of the resonator is isolated using phononic gratings all around the resonator using the metal line above and vias' to body and dummy fins on the side. As such, a Bragg reflector is formed above or below the AFE based transistor. Increased drive signal from the AFE results in larger output signal and larger bandwidth.

A piezoelectric device includes a piezoelectric body at least a portion of which can bend and vibrate, an upper electrode on an upper surface of the piezoelectric body and in which distortion of a crystal lattice is reduced as a distance from the upper surface of the piezoelectric body increases, a lower electrode on a lower surface of the piezoelectric body and in which distortion of a crystal lattice is reduced as a distance from the upper surface of the piezoelectric body increases, and a support substrate below the piezoelectric body, in which a recess extending from a lower surface of the support substrate toward the lower surface of the piezoelectric device is provided.

A piezoelectric device includes a piezoelectric single crystal body with a homogeneous polarization state and of which at least a portion flexurally vibrates, an upper electrode on an upper surface of the piezoelectric single crystal body, a lower electrode on a lower surface of the piezoelectric single crystal body, and a supporting substrate below the piezoelectric single crystal body. A recess extends from a lower surface of the supporting substrate toward the lower surface of the piezoelectric single crystal body.