A front-end module (FEM) for a 6.1 GHz Wi-Fi acoustic wave resonator RF filter circuit. The device can include a power amplifier (PA), a 6.1 GHz 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 6.1 GHZ resonator may be configured between the diversity switch and the LNA. In a specific example, this device integrates a 6.1 GHz PA, a 6.1 GHZ bulk acoustic wave (BAW) RF filter, a single pole two throw (SP2T) switch, and a bypassable LNA into a single device.

A BAW resonator with an improved lateral energy confinement is provided. The resonator has a bottom electrode in a bottom electrode layer, a top electrode in a top electrode layer and a piezoelectric layer between the bottom electrode layer and the top electrode layer. The piezoelectric layer comprises piezoelectric materials of different piezoelectric polarities.

An acoustic wave device includes a support including a cavity, a piezoelectric layer on or above the support and made of one of lithium niobate or lithium tantalate, an interdigital transducer electrode embedded in the piezoelectric layer and including surfaces opposed to each other in a thickness direction, one of the surfaces being in contact with the piezoelectric layer, and a dielectric film on the piezoelectric layer and covering the interdigital transducer electrode. The interdigital transducer electrode includes electrode fingers, at least one of which overlaps the cavity in plan view. Assuming a thickness of the piezoelectric layer is d and an electrode finger pitch of the interdigital transducer electrode is p, p/d≥ about 4.25.

Provided is an aluminum nitride film in which, aluminum nitride crystal grains containing a metal element differing from aluminum and substituting for aluminum are main crystal grains of a polycrystalline film formed of crystal grains, and a concentration of the metal element in a grain boundary between the aluminum nitride crystal grains in at least one region of first and second regions corresponding to both end portions of the polycrystalline film in a film thickness direction of the polycrystalline film is higher than a concentration of the metal element in a center region of the aluminum nitride crystal grain in the at least one region, and is higher than a concentration of the metal element in a grain boundary between the aluminum nitride crystal grains in a third region located between the first region and the second region in the film thickness direction of the polycrystalline film.

A semiconductor device is provided. The semiconductor device incudes: a first sub-semiconductor structure including a dielectric layer; and a second sub-semiconductor structure, at least including a carrier substrate, and being bonded to the first sub-semiconductor structure. The first sub-semiconductor structure or the second sub-semiconductor structure includes a charge accumulation preventing layer, and the charge accumulation preventing layer is disposed between the carrier substrate and the dielectric layer, and is configured to avoid an undesired conductive channel from being generated due to charge accumulation on a surface of the carrier substrate.

A fabrication method of a bulk acoustic wave (BAW) resonator includes: sequentially forming a buffer layer, a piezoelectric layer, and a first electrode on a temporary substrate; forming a first dielectric layer on the piezoelectric layer and covering the first electrode; forming a trench in the first dielectric layer; forming a second dielectric layer on the first dielectric layer and in the trench; forming a third dielectric layer on the second dielectric layer and filling in the trench; forming a bonding layer on the third dielectric layer; bonding a resonator substrate to the third dielectric layer via the bonding layer; removing the temporary substrate and the buffer layer to expose a surface layer of the piezoelectric layer; removing the surface layer of the piezoelectric layer; forming a second electrode on the piezoelectric layer; and removing a portion of the first dielectric layer surrounded by the trench to form a cavity.

A bulk acoustic wave (BAW) resonator includes: a substrate; a piezoelectric layer disposed above the substrate; a first electrode disposed below the piezoelectric layer; a second electrode disposed above the piezoelectric layer; a first dielectric layer disposed below the piezoelectric layer; a second dielectric layer disposed below the first dielectric layer; a cavity disposed below the first electrode; a first grounded through hole disposed in the first dielectric layer and the second dielectric layer and spaced away from the cavity; a metal bonding layer disposed between the second dielectric layer and the substrate; a second grounded through hole disposed in the piezoelectric layer and aligned with the first grounded through hole, and a ground pad metal layer disposed on the piezoelectric layer and in the second grounded through hole, and electrically connected to the metal bonding layer.

A bulk acoustic wave (BAW) resonator includes a substrate, a piezoelectric layer disposed above the substrate, a first electrode disposed below the piezoelectric layer, a second electrode disposed above the piezoelectric layer, a first dielectric layer, a second dielectric layer, and a third dielectric layer disposed between the substrate and the piezoelectric layer, and a bonding layer disposed between the third dielectric layer and the substrate. The first dielectric layer is disposed below the piezoelectric layer and includes a cavity. The third dielectric layer is disposed below the first dielectric layer and includes a protruding structure protruding towards the piezoelectric layer. The second dielectric layer overlays the third dielectric layer including the protruding structure, the second dielectric layer and the protruding structure of the third dielectric layer constituting a double-wall boundary structure surrounding the cavity.

Provided is an acoustic resonator including: a substrate including a first cavity; a first electrode formed above the substrate; a piezoelectric layer formed on one surface of the first electrode; and a second electrode formed on one surface of the piezoelectric layer, wherein the first electrode and the piezoelectric layer include an overlapping area that corresponds to a first end and a second end of the first cavity, the first electrode has a termination surface formed as an inclined surface of a first acute angle θ.sub.1 outside the overlapping area with respect to the second end of the first cavity, the piezoelectric layer is formed to include a first air bridge area that has a second cavity and is formed between the piezoelectric layer and the first electrode in a vertical direction and between the second end of the first cavity and the termination surface in a horizontal direction.

A bulk acoustic wave resonator is provided. The bulk acoustic wave resonator includes a board; a resonant portion including a first electrode, a piezoelectric layer, and a second electrode, and disposed on the board, and a temperature compensation layer disposed on the resonant portion, wherein the temperature compensation layer includes a temperature compensation portion formed of a dielectric and a loss compensation portion formed of a material different from a material of the temperature compensation portion, and wherein each of the temperature compensation portion and the loss compensation portion includes a plurality of linear patterns, and the linear patterns of the temperature compensation portion and the linear patterns of the loss compensation portion are alternately disposed.