A rectangular quartz crystal blank having long sides substantially parallel to a Z axis of the quartz crystal blank, and short sides substantially parallel to an X axis of the quartz crystal blank. The quartz crystal blank includes a center region, a second region and a third region that are adjacent to the center region along a long-side direction, and a fourth region and a fifth region that are adjacent to the first region along a short-side direction. A thickness of the second region and a thickness of the third region are smaller than a thickness of the first region, and/or a thickness of the fourth region and a thickness of the fifth region are smaller than a thickness of the first region, and 25.93W/T27.07, where W is a length of a short side and T is a thickness.

A rectangular quartz crystal blank having long sides substantially parallel to a Z axis of the quartz crystal blank, and short sides substantially parallel to an X axis of the quartz crystal blank. The quartz crystal blank includes a center region, a second region and a third region that are adjacent to the center region along a long-side direction, and a fourth region and a fifth region that are adjacent to the first region along a short-side direction. A thickness of the second region and a thickness of the third region are smaller than a thickness of the first region, and/or a thickness of the fourth region and a thickness of the fifth region are smaller than a thickness of the first region, and 20.78W/T22.10, where W is a length of a short side and T is a thickness.

The disclosure relates to the technical field of semiconductors, and discloses a method for manufacturing a resonator. The method includes: a substrate is pretreated to change a preset reaction rate of a preset region part of the substrate, so that the preset reaction rate of the preset region part is higher than that of a region outside the preset region part; a preset reaction is performed to the substrate to form a sacrificial material part including an upper half part above an upper surface of the substrate and a lower half part below a lower surface of the substrate; a multilayer structure is formed on the sacrificial material part, and includes a lower electrode layer, a piezoelectric layer and an upper electrode layer from bottom to top; and the sacrificial material part is removed.

A resonance device that includes a lower cover formed from non-degenerate silicon; a resonator having a degenerate silicon substrate with a lower surface facing the lower cover, and including first and second electrode layers laminated on the substrate with a piezoelectric film formed therebetween and having a surface opposing an upper surface of the substrate. Moreover, the lower surface of the substrate has an adjustment region where a depth or height of projections and recesses formed on the surface is larger than that in another region of the lower surface of the substrate or is a region where an area of the projections and recesses is larger than that in the other region of the lower surface of the substrate.

Techniques are disclosed for forming integrated circuit film bulk acoustic resonator (FBAR) devices having multiple resonator thicknesses on a common substrate. A piezoelectric stack is formed in an STI trench and overgrown onto the STI material. In some cases, the piezoelectric stack can include epitaxially grown AlN. In some cases, the piezoelectric stack can include single crystal (epitaxial) AlN in combination with polycrystalline (e.g., sputtered) AlN. The piezoelectric stack thus forms a central portion having a first resonator thickness and end wings extending from the central portion and having a different resonator thickness. Each wing may also have different thicknesses from one another. Thus, multiple resonator thicknesses can be achieved on a common substrate, and hence, multiple resonant frequencies on that same substrate. The end wings can have metal electrodes formed thereon, and the central portion can have a plurality of IDT electrodes patterned thereon.

A surface acoustic wave device is disclosed. The surface acoustic wave device can include a single crystal support layer, an intermediate single crystal layer positioned over the single crystal support layer, a lithium based piezoelectric layer positioned over the intermediate single crystal layer, and an interdigital transducer electrode positioned over the lithium based piezoelectric layer, the surface acoustic wave device configured to generate a surface acoustic wave. The single crystal layer can be a quartz layer, such as a z-propagation quartz layer. A thermal conductivity of the single crystal support layer is greater than a thermal conductivity of the intermediate single crystal layer, and the thermal conductivity of the single crystal support layer is greater than a thermal conductivity of the lithium based piezoelectric layer.

An acoustic wave device includes a support substrate including a hollow portion, a piezoelectric layer laminated on the support substrate and including a membrane portion at least partially overlapping the hollow portion in a lamination direction, and an electrode on the piezoelectric layer. The electrode includes an IDT electrode finger and an electrode portion other than the IDT electrode finger. The IDT electrode finger is provided on the membrane portion, and an outer contour of the electrode portion intersects with a boundary of the membrane portion in plan view.

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.

In a crystal resonator (100), a crystal resonator plate (10) includes: a vibrating part (11); an external frame part (12) provided at a side of an outer periphery of the vibrating part (11); and a penetrating part (10a) provided between the vibrating part (11) and the external frame part (12) so as to penetrate the crystal resonator plate (10) in a thickness direction of the crystal resonator plate (10). An inclined surface (11c) is provided at an end part of the vibrating part (11) at the side of the penetrating part (10a) so as to protrude in the thickness direction and to be inclined with respect to a vibrating surface (11b) of the vibrating part (11).