Guided Surface Acoustic Wave (SAW) devices with improved quartz orientations are disclosed. A guided SAW device includes a quartz carrier substrate, a piezoelectric layer on a surface of the quartz carrier substrate, and at least one interdigitated transducer on a surface of the piezoelectric layer opposite the quartz carrier substrate. The quartz carrier substrate includes an orientation that provides improved performance parameters for the SAW device, including electromechanical coupling factor, resonator quality factor, temperature coefficient of frequency, and delta temperature coefficient of frequency.

The present disclosure provides an acoustic resonator based on a high crystallinity doped piezoelectric thin film, including: a substrate; a seed layer arranged on the substrate, wherein the substrate and the seed layer form a Bragg reflection structure; a doped layer arranged on the seed layer; and a metal electrode arranged on the doped layer; wherein the seed layer is configured to increase a lattice matching degree between the doped layer and the substrate, and configured to reflect a sound wave emitted by the doped layer. The present disclosure further provides a method for preparing the acoustic resonator described above.

The present disclosure provides an acoustic resonator based on a high crystallinity doped piezoelectric thin film, including: a substrate; a seed layer arranged on the substrate, wherein the substrate and the seed layer form a Bragg reflection structure; a doped layer arranged on the seed layer; and a metal electrode arranged on the doped layer; wherein the seed layer is configured to increase a lattice matching degree between the doped layer and the substrate, and configured to reflect a sound wave emitted by the doped layer. The present disclosure further provides a method for preparing the acoustic resonator described above.

This invention focuses on minimizing the hot spots on a filter chip by creating thermal radiators using the mechano-acoustic structures and connection circuitry. A gradual increase of metal to wafer relation is made to provide better heat dissipation and heat sinking. Preferably the shunt lines of the ladder type arrangement of SAW resonators (RS1, RS2, RS3) comprise a broadened section (BBCN). Each two series resonators (RS1, RS2, RS3) that are subsequent to each other in the series signal line are connected via a common busbar (BBCN) extending over a whole length of that subsequent series resonators, a lateral extension of the common busbars represents a first section of a respective shunt line each, each first shunt line section between a node and the parallel resonator (RP1, RP2) of a shunt line (SLS1) comprises a broadened section (BS) that is broader than the common busbar, the broadened section extends over the whole width of the parallel resonator (RP1), the first reflector (REF1) of the parallel resonator that faces the laterally adjacent series resonator is formed from the broadened section (BS).

Surface acoustic wave (SAW) resonator, SAW filters, and methods of fabricating SAW filters. A first plurality of parallel conductors extending from a first bus bar are formed on a surface of a 128-degree Y-cut lithium niobate substrate. A second plurality of parallel conductors extending from a second bus bar are formed on the surface of the substrate, the second plurality of parallel conductors interleaved with the first plurality of parallel conductors. An SiO2 layer overlays the first and second pluralities of parallel conductors. The first and second pluralities of parallel conductors are substantially copper and have a thickness D.sub.CU defined by 0.12 PD.sub.CU0.24P, where P is a center-to-center spacing of adjacent parallel conductors. The SiO2 layer has a thickness D.sub.OX defined by 3.1D.sub.CUD.sub.OX4.5D.sub.CU.

Surface acoustic wave (SAW) resonator, SAW filters, and methods of fabricating SAW filters. A first plurality of parallel conductors extending from a first bus bar are formed on a surface of a 128-degree Y-cut lithium niobate substrate. A second plurality of parallel conductors extending from a second bus bar are formed on the surface of the substrate, the second plurality of parallel conductors interleaved with the first plurality of parallel conductors. An SiO2 layer overlays the first and second pluralities of parallel conductors. The first and second pluralities of parallel conductors are substantially copper and have a thickness D.sub.CU defined by 0.12 PD.sub.CU0.24P, where P is a center-to-center spacing of adjacent parallel conductors. The SiO2 layer has a thickness D.sub.OX defined by 3.1D.sub.CUD.sub.OX4.5D.sub.CU.

A duplexer includes: a first filter connected between a common terminal and a first terminal and including first series and first parallel resonators; a second filter having a passband higher than that of the first filter, connected between the common terminal and a second terminal, and including second series and second parallel resonators; a first chip including the first series and second parallel resonators mounted thereon; a second chip including the first parallel and second series resonators mounted thereon, wherein when GA and HGB represent temperature coefficients of antiresonant frequencies of the first and second series resonators, and HGA and GB represent temperature coefficients of resonant frequencies of the first and second parallel resonators, a magnitude relationship among GA, GB, HGA, and HGB is none of a relationship in which GA (GB) differs from HGA (HGB), and GB (GA) and HGB (HGA) are located between GA (GB) and HGA (HGB).

A duplexer includes: a first filter connected between a common terminal and a first terminal and including first series and first parallel resonators; a second filter having a passband higher than that of the first filter, connected between the common terminal and a second terminal, and including second series and second parallel resonators; a first chip including the first series and second parallel resonators mounted thereon; a second chip including the first parallel and second series resonators mounted thereon, wherein when GA and HGB represent temperature coefficients of antiresonant frequencies of the first and second series resonators, and HGA and GB represent temperature coefficients of resonant frequencies of the first and second parallel resonators, a magnitude relationship among GA, GB, HGA, and HGB is none of a relationship in which GA (GB) differs from HGA (HGB), and GB (GA) and HGB (HGA) are located between GA (GB) and HGA (HGB).

In the composite substrate 10, the piezoelectric substrate 12 and the support substrate 14 are bonded by direct bonding using an ion beam. One surface of the piezoelectric substrate 12 is a negatively-polarized surface 12a and another surface of the piezoelectric substrate 12 is a positively-polarized surface 12b. An etching rate at which the negatively-polarized surface 12a is etched with a strong acid may be higher than an etching rate at which the positively-polarized surface 12b is etched with the strong acid. The positively-polarized surface 12b of the piezoelectric substrate 12 is directly bonded to the support substrate 14. The negatively-polarized surface 12a of the piezoelectric substrate 12 may be etched with the strong acid.

In the composite substrate, the piezoelectric substrate and the support substrate are bonded by direct bonding using an ion beam. One surface of the piezoelectric substrate is a negatively-polarized surface and another surface of the piezoelectric substrate is a positively-polarized surface. An etching rate at which the negatively-polarized surface is etched with a strong acid may be higher than an etching rate at which the positively-polarized surface is etched with the strong acid. The positively-polarized surface of the piezoelectric substrate is directly bonded to the support substrate. The negatively-polarized surface of the piezoelectric substrate may be etched with the strong acid.