A method and structure for a transfer process for an acoustic resonator device. In an example, a bulk acoustic wave resonator (BAWR) with an air reflection cavity is formed. A piezoelectric thin film is grown on a crystalline substrate. A first patterned electrode is deposited on the surface of the piezoelectric film. An etched sacrificial layer is deposited over the first electrode and a planarized support layer is deposited over the sacrificial layer, which is then bonded to a substrate wafer. The crystalline substrate is removed and a second patterned electrode is deposited over a second surface of the film. The sacrificial layer is etched to release the air reflection cavity. Also, a cavity can instead be etched into the support layer prior to bonding with the substrate wafer. Alternatively, a reflector structure can be deposited on the first electrode, replacing the cavity.

A front end module (FEM) for a Wi-Fi acoustic wave resonator RF filter circuit. The device can include a power amplifier (PA), a resonator, and a diversity switch. The device can further include a low noise amplifier (LNA). The PA is electrically coupled to an input node and can be configured to a DC power detector or an RF power detector. The resonator can be configured between the PA and the diversity switch, or between the diversity switch and an antenna. The LNA may be configured to the diversity switch or be electrically isolated from the switch. Another resonator may be configured between the diversity switch and the LNA. In a specific example, this device integrates a PA, an RF filter, a single pole two throw (SP2T) switch, and a bypassable LNA into a single device.

A method and structure for a transfer process for an acoustic resonator device. In an example, a bulk acoustic wave resonator (BAWR) with an air reflection cavity is formed. A piezoelectric thin film is grown on a crystalline substrate. A first patterned electrode is deposited on the surface of the piezoelectric film. An etched sacrificial layer is deposited over the first electrode and a planarized support layer is deposited over the sacrificial layer, which is then bonded to a substrate wafer. The crystalline substrate is removed and a second patterned electrode is deposited over a second surface of the film. The sacrificial layer is etched to release the air reflection cavity. Also, a cavity can instead be etched into the support layer prior to bonding with the substrate wafer. Alternatively, a reflector structure can be deposited on the first electrode, replacing the cavity.

A bulk acoustic resonator, related devices including a resonator assembly, a filter, and an electronic device, and a method for manufacturing a bulk acoustic wave resonator are provided. The bulk acoustic resonator includes a substrate and an acoustic reflection component, a first electrode, a piezoelectric layer, and a second electrode that are sequentially stacked on a surface of the substrate. A first gap is provided between the first electrode and the piezoelectric layer. A second gap is provided between the piezoelectric layer and a second electrode connection part of the second electrode in addition to a part of the second electrode located within the effective resonance region. The first gap interlaces and overlaps with the second gap in a direction perpendicular to a plane where the substrate is located.

A method for forming an acoustic wave device, including steps of: forming an acoustic wave sensing part and an acoustic wave reflecting part, wherein the step of forming the acoustic wave sensing part includes: providing a first substrate, forming a sensing layer on the first substrate, forming a bottom electrode on a side of the sensing layer, and forming a filling layer on the sensing layer and the bottom electrode; and wherein the step of forming the acoustic wave reflecting part includes: providing a second substrate, forming a reflecting element on the second substrate, and forming a cover layer on the reflecting element; joining the acoustic wave sensing part and the acoustic wave reflecting part; removing the first substrate; and forming a top electrode on another side of the sensing layer, wherein the bottom electrode, the top electrode and the reflecting element are arranged correspondingly to each other.

Resonator and filter devices and methods of fabrication. A resonator chip includes a substrate, a piezoelectric plate, and an acoustic Bragg reflector between the substrate and a back surface of the piezoelectric plate. A conductor pattern on a front surface of the piezoelectric plate includes a first plurality of contact pads and an interdigital transducer (IDT). The IDT and the piezoelectric plate are configured such that a radio frequency signal applied to the IDT excites a shear primary acoustic mode within the piezoelectric plate. The acoustic Bragg reflector is configured to reflect the shear primary acoustic mode. An interposer has a second plurality of contact pads on a back surface. A seal connects a perimeter of the piezoelectric plate to a perimeter of the interposer. Each contact pad of the first plurality of contact pads is directly connected to a respective contact pad of the second plurality of contact pads.

Methods of fabricating resonator and filter devices. A first conductor pattern formed on a front surface of a piezoelectric plate includes a first plurality of contact pads and an interdigital transducer (IDT). The IDT and the piezoelectric plate are configured such that a radio frequency signal applied to the IDT excites a shear primary acoustic mode within the piezoelectric plate. An acoustic Bragg reflector is between a substrate and a back surface of the piezoelectric plate, the acoustic Bragg reflector configured to reflect the shear primary acoustic mode. A second conductor pattern including a second plurality of contact pads is formed on a back surface of the interposer. The first plurality of contact pads is directly connected to respective contact pads of the second plurality of contact pads. A perimeter of the acoustic resonator chip is sealed to a perimeter of the interposer.

In one example, an apparatus comprises an acoustic resonator, the acoustic resonator including: an electrode; and a piezoelectric layer on the electrode, in which the electrode covers entirely a surface of the piezoelectric layer, and the piezoelectric layer has a convex portion with a non-uniform thickness.

A method for forming an aluminum nitride layer (310, 320) comprises the provision of a substrate (100) and the forming of a patterned metal nitride layer (110). A bottom electrode metal layer (210) is formed on the exposed portions (101) of the substrate. An aluminum nitride layer portion (320) grown above the exposed portion (101) of the substrate (100) exhibits piezoelectric properties. An aluminum nitride layer portion (310) grown above the patterned metal nitride layer (110) exhibits no piezoelectric properties (310). Both aluminum nitride layer portions (320, 310) are grown simultaneously.

The present disclosure provides a bulk acoustic wave resonator, a method for manufacturing a bulk acoustic wave resonator and an electronic device, and belongs to the field of communication technology. The bulk acoustic wave resonator of the present disclosure includes: a first base substrate, a first electrode, a piezoelectric layer, and a second electrode; the first electrode is on the first base substrate, the second electrode is on a side of the first electrode away from the first base substrate, the piezoelectric layer is between the first electrode and the second electrode; and orthographic projections of any two of the first electrode, the piezoelectric layer and the second electrode on the first base substrate at least partially overlap with each other; wherein an acoustic velocity of a material of the piezoelectric layer is no less than 18000 m/s.