A resonator includes a silicon substrate, a bottom electrode stacked on a portion of the silicon substrate, a piezoelectric layer covering the bottom electrode and another portion of the silicon substrate, a top electrode stacked on the piezoelectric layer, and a Bragg reflecting ring. The Bragg reflecting ring is formed on a side of the piezoelectric layer connected to the top electrode and surrounds the top electrode. The Bragg reflecting ring includes a Bragg high-resistivity layer and a Bragg low-resistivity layer alternately arranged along the radial direction of the Bragg reflecting ring. An acoustic impedance of the Bragg high-resistivity layer is greater than an acoustic impedance of the Bragg low-resistivity layer. The Bragg reflecting ring forms reflection surfaces to reflect the laterally propagating clutter waves, thereby suppressing the parasitic mode in the working frequency band, improving the frequency response curve of the resonator and the overall performance of the resonator.

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.

Acoustic resonator devices and methods are disclosed. An acoustic resonator device includes a substrate having a front surface and a cavity, a perimeter of the cavity defined by a lateral etch-stop comprising etch-stop material. A back surface of a single-crystal piezoelectric plate is attached to the front surface of the substrate except for a portion of the piezoelectric plate that forms a diaphragm that spans the cavity. 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.

Methods of fabricating acoustic devices are disclosed. A lateral etch stop is formed in a substrate. A back surface of a piezoelectric plate is attached to a front surface of the substrate. A conductor pattern is formed on the front surface of the piezoelectric plate, the conductor pattern including interleaved fingers of an interdigital transducer (IDT). A cavity is etched in the substrate using an etchant introduced through one or more openings in the piezoelectric plate. A lateral extent of the cavity is defined by the lateral etch stop. After etching the cavity, a portion of the piezoelectric plate forms a diaphragm spanning the cavity with the interleaved fingers of the IDT disposed on the diaphragm.

Methods for forming a film bulk acoustic resonator (FBAR) are provided. In the method, formation of several mutually overlapped and hence connected sacrificial material layers above and under a resonator sheet facilitates the removal of the sacrificial material layers. Cavities left after the removal overlap at a polygonal area with non-parallel sides. This reduces the likelihood of boundary reflections of transverse parasitic waves causing standing wave resonance in the FBAR, thereby enhancing its performance in parasitic wave crosstalk. Further, according to the disclosure, the FBAR is enabled to be integrated with CMOS circuitry and hence exhibits higher reliability.

An acoustic resonator includes: a central portion; an extension portion extended outwardly of the central portion; a first electrode, a piezoelectric layer, and a second electrode sequentially stacked on a substrate, in the central portion; and an insertion layer disposed below the piezoelectric layer in the extension portion, wherein the piezoelectric layer includes a piezoelectric portion disposed in the central portion, and a bent portion disposed in the extension portion and extended from the piezoelectric portion at an incline depending on a shape of the insertion layer.

A MEMS device and a manufacturing method thereof. The manufacturing method comprises: forming a CMOS circuit; and forming a MEMS module on the CMOS circuit which is coupling to the MEMS module and configured to drive the MEMS module. Forming the MEMS module comprises: forming a protective layer; forming a sacrificial layer in the protective layer; forming a first electrode on the protective layer and on the sacrificial layer so that the first electrode covers the sacrificial layer, and electrically coupling the first electrode to the CMOS circuit; forming a piezoelectric layer on the first electrode and above the sacrificial layer; forming a second electrode on the piezoelectric layer and electrically coupling the second electrode to the CMOS circuit; forming a through hole to reach the sacrificial layer; and forming a cavity by removing the sacrificial layer through the through hole.

A hybrid acoustic resonator. An interdigital electrode is provided in a first region of a surface of a piezoelectric film facing away from a substrate, and forms an interdigital transducer. At least two trenches are provided in a second region of the surface of the piezoelectric film facing away from the substrate. A bulk-acoustic-wave propagation portion is formed between adjacent trenches. A bulk-acoustic-wave electrode is provided on a side surface of the bulk-acoustic-wave propagation portion, and there is an air gap at a surface of the bulk-acoustic-wave electrode facing away from the bulk-acoustic-wave propagation portion. Thereby, the hybrid acoustic resonator includes both the surface acoustic resonator and the bulk acoustic resonator. An acoustic wave in the bulk-acoustic-wave propagation portion and an acoustic wave in the interdigital transducer are both transmitted along a transversal direction.

A single-crystal bulk acoustic wave resonators with better performance and better manufacturability and a process for fabricating the same are described. A low-acoustic-loss layer of one or more single-crystal and/or poly-crystal piezoelectric materials is epitaxially grown and/or physically deposited on a surrogate substrate, followed with the formation of a bottom electrode and then a support structure on a first side of the piezoelectric layer. The surrogate substrate is subsequently removed to expose a second side of the piezoelectric layer that is opposite to the first side. A top electrode is then formed on the second side of the piezoelectric layer, followed by further processes to complete the BAW resonator and filter fabrication using standard wafer processing steps. In some embodiments, the support structure has a cavity or an acoustic mirror adjacent the first electrode layer to minimize leakage of acoustic wave energy.

An acoustic wave device system with its piezoelectric layer originating from a single crystal piezoelectric wafer/substrate is invented along with sets of detailed process steps to fabricate such a device using wafer-to-wafer and/or die-to-wafer bonding technologies. The proposed device system is particularly good to make bulk acoustic wave (BAW) devices. Methods allowing the single crystal piezoelectric wafer/substrate to be re-used are also given. The proposed methods include detailed process steps to allow heterogeneous integration of electrical chips into the system in a very cost efficient manner. The invention provides a practical and low-cost approach to fabricate the radio frequency (RF) front end chip incorporating RF filters and electronic components integrated into a small footprint which is particularly useful for mobile device and RF stations.