A method for forming a bulk acoustic wave resonance device is provided, including forming a first stack, wherein forming the first stack includes: providing a first substrate; forming a piezoelectric layer on the first substrate; forming a first electrode layer on the piezoelectric layer; and forming a cavity pretreatment layer on the piezoelectric layer, wherein a first side of the first stack corresponds to a side of the first substrate, and a second side of the first stack corresponds to a side of the cavity pretreatment layer; forming a second stack, wherein forming the second stack includes providing a second substrate; joining the first stack and the second stack, wherein the second stack is disposed at the second side of the first stack; removing the first substrate; and forming a second electrode layer at the first side of the first stack and in contact with the piezoelectric layer.

Provided in the embodiments of the present disclosure are a bulk acoustic wave resonant structure and a preparation method therefor, and an acoustic wave device. The bulk acoustic wave resonant structure comprises: a substrate; and a reflection structure, a first electrode, a piezoelectric layer and a second electrode which are sequentially located on the substrate, wherein an overlapping region of an orthographic projection of the first electrode on the substrate, an orthographic projection of the piezoelectric layer on the substrate and an orthographic projection of the second electrode on the substrate is a first overlapping region; the first electrode comprises a first portion, a second portion and a third portion, the second portion being connected to the first portion and the third portion; an orthographic projection of the first portion on the substrate falls within the first overlapping region, and the first portion extends in a direction parallel to a surface of the substrate; an orthographic projection of the second portion on the substrate and an orthographic projection of the third portion on the substrate fall within a region outside the first overlapping region, the second portion has an inclination angle relative to the surface of the substrate, and the third portion extends in a direction parallel to the surface of the substrate; and the first portion is higher than the third portion in a direction perpendicular to the surface of the substrate.

The present disclosure provides a bulk acoustic wave resonator and a manufacturing method thereof, and relates to the technical field of resonators. The bulk acoustic wave resonator includes a substrate, and a lower conductive layer, a piezoelectric layer and an upper conductive layer, which are sequentially disposed on the substrate in a stacked manner, wherein the lower conductive layer, the piezoelectric layer and the upper conductive layer have an overlapping region in a stacking direction, a first cavity located between the upper conductive layer and the piezoelectric layer is disposed outside the overlapping region, a plurality of first support columns are disposed inside the first cavity, the plurality of first support columns are supported between the piezoelectric layer and the upper conductive layer, the plurality of first support columns divide the first cavity into a plurality of through holes.

Techniques for improving Bulk Acoustic Wave (BAW) resonator structures are disclosed, including filters, oscillators and systems that may include such devices. First and second layers of piezoelectric material may be acoustically coupled with one another to have a piezoelectrically excitable resonance mode. The first layer of piezoelectric material may have a first piezoelectric axis orientation, and the second layer of piezoelectric material may have a second piezoelectric axis orientation that opposes the first piezoelectric axis orientation of the first layer of piezoelectric material. A top acoustic reflector including a first pair of top metal electrode layers may be electrically and acoustically coupled with the first layer of piezoelectric material to excite the piezoelectrically excitable main resonance mode at a resonant frequency.

Acoustic resonator devices is provided that includes a piezoelectric layer having a first surface and a second surface; and a first electrode and a second electrode on the first surface of the piezoelectric layer. At least one of the first electrode and second electrode has a side that extends at an angle relative to the first surface of the piezoelectric layer. Moreover, the angle is greater than or equal to 70 degrees and less than 90 degrees. Furthermore, a thickness of the piezoelectric layer is less than a distance between a center of the first electrode and a center of the second electrode.

A stacked die XBAR filter device includes a first die containing one or more XBARs on a first surface, a second die containing one or more XBARs on a second surface, and one or more conductive vias through either the first die or the second die, where the first die is connected to the second die with the first surface facing the second surface.

As disclosed herein, methods of forming a piezoelectric resonator device can include forming a first stack of piezoelectric layers having alternating opposing ferroelectric polarizations comprising the following operations: (a) depositing a first material, including metal and nitrogen atoms, on a surface to form a first piezoelectric layer having a first ferroelectric polarization, (b) forming a first layer including Al on the first piezoelectric layer, (c) depositing a second material including the metal and the nitrogen atoms on the first layer to form a second piezoelectric layer having the first ferroelectric polarization, (d) forming first poling electrodes electrically laterally spaced apart from one another on a surface of the second piezoelectric layer and (e) applying a voltage across the first poling electrodes to change the first ferroelectric polarization of the second piezoelectric layer to a second ferroelectric polarization that is opposite to the first ferroelectric polarization.

A bulk acoustic wave resonator and a method for manufacturing therefor are provided. The bulk acoustic wave resonator includes a substrate, a lower conductive layer, a piezoelectric layer, and an upper conductive layer. At least one first cavity located between the upper conductive layer and the piezoelectric layer is provided at a boundary of an overlapping area. A plurality of first support columns are provided in the at least one first cavity. The plurality of first support columns are used for dividing the at least one first cavity into a plurality of through holes at least partially located in the overlapping area. The plurality of through holes are arranged in a direction from a center of the overlapping area to the boundary.

A method for preparing a hybrid filter on a chip with IPD and FBAR, includes: preparing a leakage isolation layer on a supporting substrate by deposition; obtaining an inductor layer on the leakage isolation layer, leaving a window at a bottom of a groove surrounding a cross section of a TGV inductor stack on a mask, and patterning an inductor metal simultaneously; forming a first insulating layer on the inductor metal, and forming lead through holes by photolithography; repeating steps and alternately to obtain a three-layer stacked TGV inductor; depositing a second insulating layer on the TGV inductor; depositing two capacitor layers on the second insulating layer, and depositing a third insulating layer between the two capacitor layers to form an MIM capacitor; and preparing a BAW resonator on the MIM capacitor, and connecting the TGV inductor, the MIM capacitor and the BAW resonator through the lead through holes.

An acoustic wave device includes a substrate, lower and upper electrodes provided over the substrate, a piezoelectric film that is provided over the substrate, is interposed between the lower and upper electrodes, and has a pair of through holes that sandwich a resonance region therebetween in a first direction, are provided along the resonance region, and are connected to an air gap that is formed between the substrate and the lower electrode and overlaps the resonance region in the plan view, the lower and upper electrodes overlapping across the piezoelectric film in the resonance region, and additional films that are not provided in a central region of the resonance region in the plan view and are provided in respective edge regions, which are located on respective sides of the central region in a second direction substantially orthogonal to the first direction in the plan view, of the resonance region.