An RF circuit device using modified lattice, lattice, and ladder circuit topologies. The devices can include four resonator devices and four shunt resonator devices. In the ladder topology, the resonator devices are connected in series from an input port to an output port while shunt resonator devices are coupled to the nodes between the resonator devices. In the lattice topology, a top and a bottom serial configurations each includes a pair of resonator devices that are coupled to differential input and output ports. A pair of shunt resonators is cross-coupled between each pair of a top serial configuration resonator and a bottom serial configuration resonator. The modified lattice topology adds baluns or inductor devices between top and bottom nodes of the top and bottom serial configurations of the lattice configuration. These topologies may be applied using single crystal or polycrystalline bulk acoustic wave (BAW) resonators.

Acoustic resonator devices, filters, and methods are disclosed. An acoustic resonator includes a substrate and a lithium niobate (LN) plate having front and back surfaces and a thickness ts. The back surface is attached to a surface of the substrate. A portion of the LN plate forms a diaphragm spanning a cavity in the substrate. An interdigital transducer (IDT) is formed on the front surface of the LN plate with interleaved fingers of the IDT disposed on the diaphragm. The LN plate and the IDT are configured such that a radio frequency signal applied to the IDT excites a shear primary acoustic wave in the diaphragm. Euler angles of the LN plate are [0°, β, 0° ], where 0≤β≤60°. A thickness of the interleaved fingers of the IDT is greater than or equal to 0.8 ts and less than or equal to 2.0 ts.

Acoustic filters are disclosed. A bandpass filter has a passband between a lower band edge and an upper band edge. The bandpass filter includes a plurality of transversely-excited film bulk acoustic resonators (XBARs) connected in a ladder filter circuit. The plurality of XBARs includes at least one lithium tantalate XBAR and at least one lithium niobate XBAR.

Acoustic resonator devices, filter devices, and methods of fabrication are disclosed. An acoustic resonator includes a substrate having a surface and a single-crystal piezoelectric plate having front and back surfaces. The back surface is attached to the surface of the substrate except for a portion of the piezoelectric plate forming a diaphragm that spans a cavity in the substrate. An interdigital transducer (IDT) is formed on the front surface of the single-crystal piezoelectric plate such that interleaved fingers of the IDT are disposed on the diaphragm. The IDT is configured to excite a primary acoustic mode in the diaphragm in response to a radio frequency signal applied to the IDT. The interleaved fingers extend at an oblique angle to an Z crystalline axis of the piezoelectric plate.

Acoustic resonator devices and filters are disclosed. An acoustic resonator includes a substrate having a trap-rich region adjacent to a surface and a single-crystal piezoelectric plate having parallel front and back surfaces, the back surface attached to the surface of the substrate except for a portion of the piezoelectric plate forming a diaphragm that spans a cavity in the substrate. An interdigital transducer (IDT) is formed on the front surface of the single-crystal piezoelectric plate such that interleaved fingers of the IDT are disposed on the diaphragm. The single-crystal piezoelectric plate and the IDT are configured such that a radio frequency signal applied to the IDT excites a shear primary acoustic mode within the diaphragm.

Acoustic resonators and filter devices. An acoustic resonator includes a piezoelectric plate having front and back surfaces, a portion of the piezoelectric plate forming a diaphragm, a conductor pattern on the front surface, the conductor pattern including an interdigital transducer (IDT), fingers of the IDT on the diaphragm, and a front-side dielectric layer on the front surface of the piezoelectric plate between the interleaved fingers. A resonant frequency is determined, in part, by a thickness of the front-side dielectric layer. A ratio of a mark of the interleaved fingers to a pitch of the interleaved fingers is greater than or equal to 0.12 and less than or equal to 0.3.

An acoustic resonator device with low thermal impedance has a substrate and a single-crystal piezoelectric plate having a back surface attached to a top surface of the substrate via a bonding oxide (BOX) layer. An interdigital transducer (IDT) formed on the front surface of the plate has interleaved fingers disposed on the diaphragm. The piezoelectric plate and the BOX layer are removed from a least a portion of the surface area of the device to provide lower thermal resistance between the conductor pattern and the substrate.

An integrated structure of crystal resonator and control circuit and an integration method therefor. The crystal resonator is formed by first forming the lower cavity (120) in the device wafer (100) containing the control circuit (110), forming the piezoelectric vibrator (200) on the device wafer (100) and then enclosing the piezoelectric vibrator (200) within the upper cavity (400) through forming the cap layer (420) using a planar fabrication process. In addition, a semiconductor die (500) is bonded to the same device wafer (100), helping in enhancing device performance by allowing on-chip modulation of the crystal resonator's parameters. In this way, in addition to being able to integrate with other semiconductor components more easily with a higher degree of integration, the crystal resonator is more compact in size and less power-consuming.

An integrated structure of crystal resonator and control circuit and an integration method therefor. A lower cavity is formed in a device wafer, and an upper cavity is formed in a substrate. A bonding process is then performed to bond the device wafer and the substrate together in such a manner that a piezoelectric vibrator is sandwiched between the device wafer and the substrate, with the lower and upper cavities being located on opposing sides of the piezoelectric vibrator, thus resulting in the formation of the crystal resonator. Moreover, the crystal resonator is brought into electrical connection with the control circuit, achieving integration of the two. This crystal resonator is more compact in size, less power-consuming and easier to integrate with other semiconductor components with a higher degree of integration, compared with traditional crystal resonators.

An integrated structure of crystal resonator and control circuit (110) and an integration method therefor. A lower cavity (102) is formed in a device wafer (100) containing the control circuit (110), and an upper cavity (310) is formed in a substrate (300). A bonding process is performed to bond the substrate (300) to the device wafer (100) in such a manner that the piezoelectric vibrator (200) is sandwiched between the device wafer (100) and the substrate (300). In this way, integration of the crystal resonator and the control circuit (110) is achieved. A semiconductor die (600) can be further bonded to the same semiconductor substrate. This helps in improving performance of the crystal resonator by allowing on-chip modulation of its parameters. This crystal resonator is more compact in size, less power-consuming and easier to integrate with other semiconductor components with a higher degree of integration, compared with traditional crystal resonators.