Techniques for improving Bulk Acoustic Wave (BAW) reflector and resonator structures are disclosed, including filters, oscillators and systems that may include such devices. A Bulk Acoustic Wave (BAW) resonator of this disclosure may comprise a substrate and an active piezoelectric resonant volume. The active piezoelectric resonant volume of the Bulk Acoustic Wave (BAW) resonator may have a main resonant frequency. The active piezoelectric resonant volume of the Bulk Acoustic Wave (BAW) resonator may comprise first and second piezoelectric layers having respective piezoelectric axis that substantially oppose one another. A first patterned layer may be disposed within the active piezoelectric volume. This may, but need not facilitate suppression of spurious modes. The main resonant frequency of the Bulk Acoustic Wave (BAW) resonator may be in a super high frequency (SHF) band. The main resonant frequency of the Bulk Acoustic Wave (BAW) resonator may be in an extremely high frequency (EHF) band.

An integrated bulk acoustic wave resonator-capacitor comprises a membrane including a piezoelectric film, an upper electrode disposed on a top surface of the piezoelectric film, and a lower electrode disposed on a lower surface of the piezoelectric film, a resonator region of the membrane defining a main active domain in which a main acoustic wave is generated during operation, and a capacitor region of the membrane surrounding the resonator region, the capacitor region including a layer of conductive material disposed on the upper electrode, an inner capacitor raised frame defined on an inner peripheral region of the layer of conductive material, and an outer capacitor raised frame defined on an outer peripheral region of the layer of conductive material.

A bulk-acoustic wave resonator comprises a substrate, a resonant portion comprising a first electrode, a piezoelectric layer, and a second electrode sequentially stacked on the substrate, and further comprising a center portion and an extension portion that is disposed along a periphery of the center portion, and an insertion layer that is disposed in the extension portion between the first electrode and the piezoelectric layer, and the insertion layer is formed of an aluminum alloy containing scandium (Sc).

A resonator circuit device. This device can include a piezoelectric layer having a front-side electrode and a back-side electrode spatially configured on opposite sides of the piezoelectric layer. Each electrode has a connection region and a resonator region. Each electrode also includes a partial mass-loaded structure configured within a vicinity of its connection region. The front-side electrode and the back-side electrode are spatially configured in an anti-symmetrical manner with the resonator regions of both electrodes at least partially overlapping and the first and second connection regions on opposing sides. This configuration provides a symmetric acoustic impedance profile for improved Q factor and can reduce the issues of misalignment or unbalanced boundary conditions associated with conventional single mass-loaded perimeter configurations.

Disclosed 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. Here, the piezoelectric layer includes a longitudinal section not to cover a longitudinal section of the first electrode. Also, the second electrode covers the longitudinal section of the piezoelectric layer and extends to a first interpolar cavity which spaces the first electrode at least partially apart from the piezoelectric layer. A quality factor may be increased by fixing an increase in resistance which occurs due to thin film electrodes.

A bulk acoustic wave resonator device comprises a piezoelectric material layer, a first metal layer having a lower surface disposed on the upper surface of the piezoelectric material layer, a second metal layer having an upper surface disposed on the lower surface of the piezoelectric material layer, and an oxide raised frame disposed between the lower surface of the first metal layer and the upper surface of the second metal layer and surrounding a central active region of the bulk acoustic wave resonator device, the central active region having a first side and a second side, the oxide raised frame having a width on the first side of the central active region that is different from the width of the oxide raised frame on the second side of the central active region to improve an operating parameter of the bulk acoustic wave resonator.

Provided is a method of manufacturing a bulk acoustic wave resonator, which includes: providing a piezoelectric substrate for forming a piezoelectric layer; forming a first electrode structure on the portion of the piezoelectric substrate for forming the piezoelectric layer; forming a dielectric layer on the first electrode structure, and performing a patterning process on the dielectric layer to form a patterned dielectric layer comprising a sacrificial dielectric part and a periphery dielectric part; forming a boundary layer on the patterned dielectric layer, the boundary layer covering a surface of the patterned dielectric layer and surrounding the sacrificial dielectric part; thinning the piezoelectric substrate to form the piezoelectric layer, the first electrode structure being located at a first side of the piezoelectric layer; forming a second electrode structure on a second side of the piezoelectric layer; and removing the sacrificial dielectric part to form a resonant cavity.

The invention provides a film bulk acoustic resonator including a layered structure composed of a top electrode, a piezoelectric layer and a bottom electrode, and a substrate; a reflective interface is arranged between the bottom electrode and the substrate; and by defining the shape of all or part of the layered structure, the purpose of suppressing the lateral mode can be achieved, and without adding new process, the manufacturing cost of the device can be controlled, and the benefit of product development can be maximized.

A method for forming a bulk acoustic wave resonance device, comprising: (S201) forming a first layer, which comprises: providing a first substrate; forming a piezoelectric layer located on the first substrate; forming a first electrode layer located on the piezoelectric layer; and forming a cavity pre-treatment layer located on the piezoelectric layer, used for forming a cavity, and at least covering a first end of the first electrode layer, wherein a first side of the first layer corresponds to the side of the first substrate; a second side of the first layer corresponds to the side of the cavity pre-treatment layer; (S203) forming a second layer, which comprises: providing a second substrate; (S205) connecting the first layer to the second layer, the second layer being located at the second side; (S207) removing the first substrate, so that the first side corresponds to the side of the piezoelectric layer; and (S209) forming a second electrode layer located at the first side and contacting with the piezoelectric layer. The formed piezoelectric layer does not comprise a crystal that is significantly turned so as to facilitate increasing the electromechanical coupling coefficient and the Q value of the resonance device. In addition, the second substrate processing and the active layer processing can be respectively performed, and are flexible.

An acoustic wave device including: a POI structure including: a material layer where a high acoustic velocity layer and a low acoustic velocity layer are alternate, a substrate is a lowermost high acoustic velocity layer; a first piezoelectric layer located above the material layer, wherein a layer adjacent to the first piezoelectric layer is referred to as a surface low acoustic velocity layer; wherein an acoustic velocity of a bulk wave propagated in the high acoustic velocity layer and the low high acoustic velocity layer is higher than and lower than an acoustic velocity of a bulk wave of the first piezoelectric layer, respectively. The POI structure includes at least two regions, a first device having a resonance of a first vibration mode is manufactured in the first region, and a second device having a resonance of a second vibration mode is manufactured in a second region.