The present disclosure relates to a Bulk Acoustic Wave (BAW) resonator, which includes a bottom electrode, a top electrode structure, and a ferroelectric layer sandwiched in between. Herein, the ferroelectric layer is formed of a ferroelectric material, which has a box-shape polarization-electric field (P-E) curve. The ferroelectric layer includes a ferroelectric border (BO) portion positioned at a periphery of the ferroelectric layer and a ferroelectric central portion surrounded by the ferroelectric BO portion. The ferroelectric BO portion has a first polarization and a first electromechanical coupling coefficient, and the ferroelectric central portion has a second polarization and a second electromechanical coupling coefficient. An absolute value of the first polarization is less than an absolute value of the second polarization, and the first electromechanical coupling coefficient is less than the second electromechanical coupling coefficient. The ferroelectric central portion is configured to provide a resonance of the BAW resonator.

A resonance device is provided that includes a lower lid that has a recessed portion, and a resonator that is mounted on the lower lid and has a vibration arm that performs out-of-plane bending vibration in a space including the recessed portion and a frame provided around the vibration arm and having a facing portion facing a tip of the vibration arm. The facing portion of the frame is located in an outer-side portion of the resonator with respect to a straight line connecting an intersection point of a perpendicular extending from the tip of the vibration arm toward the recessed portion of the lower lid and the recessed portion of the lower lid, to a cavity edge of the recessed portion facing the tip of the vibration arm.

An acoustic wave device includes a piezoelectric body made of lithium niobate and disposed directly or indirectly on a supporting substrate, and IDT electrode disposed directly or indirectly on the piezoelectric body. When the wavelength of an acoustic wave that is determined by a pitch of electrode fingers of the IDT electrode is denoted by λ, the thickness of the piezoelectric body is equal to or less than about 1λ. The acoustic wave device uses the plate wave S0 mode propagating in the piezoelectric body. The Euler angles of the lithium niobate are (0°±10°, θ, 90°±10°), provided that θ is from about 0° to about 180° inclusive.

An acoustic resonator with a reinforcing structure is provided according to the present disclosure. The acoustic resonator includes a substrate and a cavity formed on the substrate, a piezoelectric layer is arranged above the substrate and an opening passing through the piezoelectric layer is formed in a peripheral region of the piezoelectric layer. The reinforcing structure includes a reinforcing layer, part of the reinforcing layer is formed at the edge of the opening with being fitted to the edge, to reinforce a resonant functional layer near the edge of the opening, which can reduce a change in stress of the piezoelectric layer and the lower electrode near the edge of the opening after the cavity is released, so that the piezoelectric layer and the lower electrode do not easily collapse due to stress, thereby ensuring the performance of a device. A method for manufacturing the same is further provided.

Techniques for improving Bulk Acoustic Wave (BAW) reflector and resonator structures are disclosed, including filters, oscillators and systems that may include such devices. A Bulk Acoustic Wave (BAW) resonator of this disclosure may comprise a substrate and an active piezoelectric resonant volume. The active piezoelectric resonant volume of the Bulk Acoustic Wave (BAW) resonator may have a main resonant frequency. The active piezoelectric resonant volume of the Bulk Acoustic Wave (BAW) resonator may comprise first and second piezoelectric layers having respective piezoelectric axis that substantially oppose one another. A first patterned layer may be disposed within the active piezoelectric volume. This may, but need not facilitate suppression of spurious modes. The main resonant frequency of the Bulk Acoustic Wave (BAW) resonator may be in a super high frequency (SHF) band. The main resonant frequency of the Bulk Acoustic Wave (BAW) resonator may be in an extremely high frequency (EHF) band.

A resonator circuit device. This device can include a piezoelectric layer having a front-side electrode and a back-side electrode spatially configured on opposite sides of the piezoelectric layer. Each electrode has a connection region and a resonator region. Each electrode also includes a partial mass-loaded structure configured within a vicinity of its connection region. The front-side electrode and the back-side electrode are spatially configured in an anti-symmetrical manner with the resonator regions of both electrodes at least partially overlapping and the first and second connection regions on opposing sides. This configuration provides a symmetric acoustic impedance profile for improved Q factor and can reduce the issues of misalignment or unbalanced boundary conditions associated with conventional single mass-loaded perimeter configurations.

An integrated circuit (IC) resonator module for an IC package includes an acoustic resonator having a surface and a Bragg reflector adhered to the surface of the acoustic resonator. The Bragg reflector includes low impedance layers formed of a first material with a first acoustic impedance and a high impedance layer formed of a second material with a second acoustic impedance. The second acoustic impedance is greater than the first acoustic impedance. The Bragg reflector further includes a Bragg grating layer formed of randomly or periodically spaced patches of the second material separated by vias filled with the first material.

A bulk acoustic wave resonator device comprises a piezoelectric material layer, a first metal layer having a lower surface disposed on the upper surface of the piezoelectric material layer, a second metal layer having an upper surface disposed on the lower surface of the piezoelectric material layer, and an oxide raised frame disposed between the lower surface of the first metal layer and the upper surface of the second metal layer and surrounding a central active region of the bulk acoustic wave resonator device, the central active region having a first side and a second side, the oxide raised frame having a width on the first side of the central active region that is different from the width of the oxide raised frame on the second side of the central active region to improve an operating parameter of the bulk acoustic wave resonator.

A filter includes a support substrate, a piezoelectric layer, one or more series resonators connected in series between input and output terminals, each having first electrode fingers having a first average pitch, one or more parallel resonators having one end connected to a path and another end connected to a ground, each having second electrode fingers having a second average pitch more than a maximum first average pitch, another resonator having one end connected to the path, and having third electrode fingers having a third average pitch less than or equal to an intermediate value between the maximum first average pitch and a minimum second average pitch, and an inductor having one end connected to the another resonator and another end connected to the ground, and having an inductance more than a maximum inductance of another inductor connected between the parallel resonators and the ground.

A vibrating arm of a vibrator element has a first surface, a second surface at an opposite side to the first surface in a Z direction, a first side surface and a second side surface as side surfaces, and a third side surface as a tip surface. At least one of the first side surface, the second side surface, and the third side surface includes a first side surface part tilted with respect to a Z direction, and a second side surface part tilted toward the first surface or the second surface with respect to the first side surface part. The first weight is arranged so that an outer edge of the first weight is located at inner side of innermost parts in the first side surface part and the second side surface part, or at the same position as the innermost parts when viewed from the Z direction.