Abstract: 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.

Abstract: A fabrication method of a surface acoustic wave (SAW) filter includes obtaining a piezoelectric substrate, forming a back electrode on a first portion of the piezoelectric substrate, forming a first dielectric layer on the first portion of the piezoelectric substrate, forming a trench in the first dielectric layer, forming a second dielectric layer on the first dielectric layer formed with the trench, forming a third dielectric layer on the second dielectric layer, removing a second portion of the piezoelectric substrate to obtain a piezoelectric layer, forming an interdigital transducer (IDT) on the piezoelectric layer, and etching and releasing a portion of the first dielectric layer surrounded by the trench to form a cavity below the back electrode.

Abstract: A surface acoustic wave (SAW) filter includes a bottom substrate, a piezoelectric layer disposed above the bottom substrate, the piezoelectric layer having a bottom surface facing the bottom substrate and a top surface opposite to the bottom surface, a lower cavity disposed below the piezoelectric layer, an interdigital transducer (IDT) disposed on the top surface of the piezoelectric layer, and a back electrode disposed on the bottom surface of the piezoelectric layer, and exposed in the lower cavity.

Abstract: A surface acoustic wave (SAW) filter includes a bottom substrate, a piezoelectric layer disposed above the bottom substrate, the piezoelectric layer having a bottom surface facing the bottom substrate and a top surface opposite to the bottom surface, a lower cavity disposed below the piezoelectric layer, an interdigital transducer (IDT) disposed on the top surface of the piezoelectric layer, and a back electrode disposed on the bottom surface of the piezoelectric layer, and exposed in the lower cavity.

Abstract: A radio frequency front-end module, a manufacturing method thereof and a communication device are provided. The radio frequency front-end module includes a first base substrate and a metal bonding structure; a second functional substrate, including a second base substrate, a groove in the second base substrate, and a bonding metal layer; and a first radio frequency front-end component, at least partially located in the groove, the first base substrate and the second base substrate are oppositely arranged, and a surface of the second base substrate close to the first base substrate includes a groove surface inside the groove and a substrate surface outside the groove, and the bonding metal layer includes a first metal portion located on the groove surface and a second metal portion located on the substrate surface, the first radio frequency front-end component is at least partially surrounded by the first metal portion.

Abstract: A surface acoustic wave resonator structure and a method of forming the resonator structure and a filter are provided.

Abstract: 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.

Abstract: A bulk acoustic wave resonator and a method of manufacturing the same are provided. The bulk acoustic wave resonator includes: a first carrier substrate; a barrier layer on a main surface of the first carrier substrate and configured to prevent an undesired conductive channel from being generated due to charge accumulation on the main surface; a buffer layer on a side of the barrier layer away from the first carrier substrate; a piezoelectric layer on a side of the buffer layer away from the barrier layer; a first electrode and a second electrode on opposite sides of the piezoelectric layer; a first passivation layer and a second passivation layer, respectively covering sidewalls of the first electrode and the second electrode; a dielectric layer between the first passivation layer and the buffer layer, wherein a first cavity is provided between the first passivation layer and the dielectric layer.

Abstract: A method for fabricating a device having a cavity, includes: obtaining a device wafer including a first substrate and a device structure formed on the first substrate, depositing a first dielectric layer on the device wafer, etching the first dielectric layer to expose at least a part of the device structure and a part of the first substrate, depositing, after the etching, a second dielectric layer on the device wafer and the first dielectric layer, performing a surface treatment on a surface of the second dielectric layer, obtaining a second substrate, and bonding the second substrate with the second dielectric layer on the device wafer, thereby forming the cavity between the second substrate and the device wafer.

Abstract: A bulk acoustic wave resonator and a method of manufacturing the same are provided. The bulk acoustic wave resonator includes: a first carrier substrate; a barrier layer on a main surface of the first carrier substrate and configured to prevent an undesired conductive channel from being generated due to charge accumulation on the main surface; a buffer layer on a side of the barrier layer away from the first carrier substrate; a piezoelectric layer on a side of the buffer layer away from the barrier layer; a first electrode and a second electrode on opposite sides of the piezoelectric layer; a first passivation layer and a second passivation layer, respectively covering sidewalls of the first electrode and the second electrode; a dielectric layer between the first passivation layer and the buffer layer, wherein a first cavity is provided between the first passivation layer and the dielectric layer.

Abstract: A surface acoustic wave (SAW) filter includes a bottom substrate, a piezoelectric layer disposed above the bottom substrate, the piezoelectric layer having a bottom surface facing the bottom substrate and a top surface opposite to the bottom surface, a lower cavity disposed below the piezoelectric layer, an interdigital transducer (IDT) disposed on the top surface of the piezoelectric layer, and a back electrode disposed on the bottom surface of the piezoelectric layer, and exposed in the lower cavity.

Abstract: A bulk acoustic wave resonator is provided. The bulk acoustic wave resonator incudes a carrier substrate, having a main surface extending along a first direction; a piezoelectric layer, located on a side of the carrier substrate in a second direction perpendicular to the main surface of the carrier substrate; a first electrode and a second electrode; a cavity boundary structure, having a body part extending along the first direction and a protruding part protruding from the body part toward the piezoelectric layer; a resonant cavity, defined by the cavity boundary structure and the piezoelectric layer; and a periphery dielectric layer, located on a side of the protruding part of the cavity boundary structure away from the resonant cavity, a material of the periphery dielectric layer is different from a material of at least a portion of the protruding part adjacent to the periphery dielectric layer.

Abstract: A surface acoustic wave resonator structure and a method of forming the resonator structure and a filter are provided.

Abstract: 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.

Abstract: A radio frequency front-end module, a manufacturing method thereof and a communication device are provided. The radio frequency front-end module includes a first base substrate and a metal bonding structure; a second functional substrate, including a second base substrate, a groove in the second base substrate, and a bonding metal layer; and a first radio frequency front-end component, at least partially located in the groove, the first base substrate and the second base substrate are oppositely arranged, and a surface of the second base substrate close to the first base substrate includes a groove surface inside the groove and a substrate surface outside the groove, and the bonding metal layer includes a first metal portion located on the groove surface and a second metal portion located on the substrate surface, the first radio frequency front-end component is at least partially surrounded by the first metal portion.

Abstract: A method for fabricating a device having a cavity, includes: obtaining a device wafer including a first substrate and a device structure formed on the first substrate, depositing a first dielectric layer on the device wafer, etching the first dielectric layer to expose at least a part of the device structure and a part of the first substrate, depositing, after the etching, a second dielectric layer on the device wafer and the first dielectric layer, performing a surface treatment on a surface of the second dielectric layer, obtaining a second substrate, and bonding the second substrate with the second dielectric layer on the device wafer, thereby forming the cavity between the second substrate and the device wafer.

Abstract: 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.

Abstract: 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.

Abstract: A surface acoustic wave (SAW) filter includes a bottom substrate, a piezoelectric layer disposed above the bottom substrate, the piezoelectric layer having a bottom surface facing the bottom substrate and a top surface opposite to the bottom surface, a lower cavity disposed below the piezoelectric layer, an interdigital transducer (IDT) disposed on the top surface of the piezoelectric layer, and a back electrode disposed on the bottom surface of the piezoelectric layer, and exposed in the lower cavity.

Abstract: A surface acoustic wave (SAW) filter includes a bottom substrate, a piezoelectric layer disposed above the bottom substrate and having a bottom surface facing the bottom substrate and a top surface opposite to the bottom surface, a cavity disposed below the piezoelectric layer, a first interdigital transducer (IDT) disposed on the bottom surface of the piezoelectric layer, and a second IDT disposed on the top surface of the piezoelectric layer. An interdigital portion of the first IDT is exposed in the cavity. An interdigital portion of the second IDT is vertically aligned with the interdigital portion of the first IDT.