阅读说明：本技术 一种双工器 (Duplexer ) 是由 孙成亮 曲远航 罗天成 谷曦宇 高超 王雅馨 王瑶 温志伟 于 2020-12-16 设计创作，主要内容包括：本发明涉及射频滤波器和双工器技术,具体涉及一种双工器,包括衬底基板以及位于衬底基板上的不同频带的接收端滤波器和发射端滤波器；接收端滤波器和发射端滤波器均包括多个堆叠式体声波谐振器,堆叠式体声波谐振器包括衬底、声反射层、底电极、多层压电材料层、多层中间电极层和顶电极。堆叠式体声波谐振器通过压电材料层和各电极层形成多层压电振荡堆串联结构,可以提高谐振器的谐振频率,本发明通过对堆叠式体声波谐振器的堆叠层数进行调整,从而对单个谐振器的谐振频率进行调频,使接收滤波器和发射滤波器的谐振器的谐振频率进行匹配,从而实现双工器的集成。(The invention relates to the technology of radio frequency filters and duplexers, in particular to a duplexer, which comprises a substrate, and a receiving end filter and a transmitting end filter which are positioned on the substrate and have different frequency bands; the receiving end filter and the transmitting end filter respectively comprise a plurality of stacked bulk acoustic wave resonators, and each stacked bulk acoustic wave resonator comprises a substrate, an acoustic reflection layer, a bottom electrode, a plurality of piezoelectric material layers, a plurality of intermediate electrode layers and a top electrode. The stacked bulk acoustic wave resonator can improve the resonant frequency of the resonator by forming a multi-layer piezoelectric oscillation stack series structure through the piezoelectric material layers and the electrode layers.)

1. A duplexer is characterized by comprising a substrate base plate, a receiving end filter and a transmitting end filter, wherein the receiving end filter and the transmitting end filter are positioned on the substrate base plate and have different frequency bands; the receiving-end filter and the transmitting-end filter each include a plurality of stacked bulk acoustic wave resonators.

2. The duplexer of claim 1, wherein the stacked bulk acoustic wave resonator comprises a substrate, an acoustic reflection layer, a bottom electrode, a plurality of piezoelectric material layers, a plurality of intermediate electrode layers, and a top electrode.

3. The duplexer of claim 2, wherein the substrate is any one of a silicon substrate, a silicon carbide substrate, a sapphire substrate, or an SOI substrate.

4. The duplexer as claimed in claim 2, wherein the bottom electrode, the top electrode and the middle electrode layer are metal electrodes selected from one or more of molybdenum, platinum, gold, silver, aluminum, tungsten, titanium, copper, ruthenium and chromium; the piezoelectric material layer is selected from one or more of aluminum nitride, zinc oxide, lithium niobate, PZT and barium sodium niobate.

5. The duplexer as claimed in claim 2, wherein the acoustic reflection layer is a bragg reflection layer or a phononic crystal structure formed by alternating air, high acoustic impedance material and low acoustic impedance material.

Technical Field

The invention belongs to the technical field of radio frequency filters and duplexers, and particularly relates to a duplexer.

Background

In a mobile communication device, a filter is a core component that enables communication exchange. With the arrival of the 5G era, the mobile communication field is continuously developing toward the target of higher frequency and wider frequency band, and the smart communication device is developing toward miniaturization and lightness. However, as the frequency band for data communication and transmission is higher and higher, the frequency range covered by the mobile communication is larger and larger, which means that more and more filters are required to select and transmit data to meet the requirement of full-band communication, and the miniaturization of the mobile communication device is hindered. The purpose of a duplexer is to separate the modulated transmit and receive signals at the antenna of a cellular radio. Therefore, more and more duplexers are used in mobile communication devices to realize broadband communication functions while keeping the mobile communication devices light, thin and small.

The duplexer is used for sharing transmission and reception of signals through one antenna in a frequency division system, and performs processing such as filtering selection of signals through an internal transmitting side filter (TX) and a receiving side filter (RX). A conventional duplexer is based on a Bulk Acoustic Wave (FBAR) Resonator and a Surface Acoustic Wave (SAW) Resonator, and is constructed by using an FBAR filter and a SAW filter, respectively. However, with the increasing communication frequency, the SAW filter has a central frequency of only about 2GHz due to the limitation of its own structure and the property of the surface acoustic wave, and cannot meet the requirement of 5G communication frequency. The bulk acoustic wave resonant frequency is determined by the thickness of the piezoelectric layer, the central frequency of the FBAR filter can reach a 5G frequency band, but when the ultra-high frequency band of 5G or even more than 6G is met, the piezoelectric film layer of the FBAR filter is reduced to hundreds of nanometers or even dozens of nanometers, so that the performance of the piezoelectric material is seriously reduced due to the film defects, a pseudo mode and other parasitic modes are brought, the performance of a device is reduced, and the process difficulty is greatly increased.

The traditional bulk acoustic wave resonator improves the frequency of the resonator by reducing the thickness of the piezoelectric material layer and the electrode, but when the material is too thin, the processing difficulty is increased, and simultaneously, the defect is brought to reduce the performance of the piezoelectric material, and a pseudo mode and a parasitic mode are generated.

Disclosure of Invention

In view of the problems of the background art, the present invention provides a duplexer based on stacked bulk acoustic wave resonators.

In order to solve the technical problems, the invention adopts the following technical scheme: a duplexer comprises a substrate base plate, a receiving end filter and a transmitting end filter which are positioned on the substrate base plate and have different frequency bands; the receiving-end filter and the transmitting-end filter each include a plurality of stacked bulk acoustic wave resonators.

In the above-described duplexer, the stacked bulk acoustic wave resonator includes a substrate, an acoustic reflection layer, a bottom electrode, a plurality of piezoelectric material layers, a plurality of intermediate electrode layers, and a top electrode.

In the above-described duplexer, the substrate is any of a silicon substrate, a silicon carbide substrate, a sapphire substrate, and an SOI substrate.

In the duplexer, the bottom electrode, the top electrode and the middle electrode layer are metal electrodes, and one or more of molybdenum, platinum, gold, silver, aluminum, tungsten, titanium, copper, ruthenium and chromium are selected; the piezoelectric material layer is selected from one or more of aluminum nitride, zinc oxide, lithium niobate, PZT and barium sodium niobate.

In the duplexer, the acoustic reflection layer is a bragg reflection layer or a phononic crystal structure formed by alternately using air, a high acoustic impedance material and a low acoustic impedance material.

Compared with the prior art, the invention improves the resonance frequency of the bulk acoustic wave resonator by adjusting the layer number of the piezoelectric material layer and the intermediate electrode layer under the condition of not changing the thickness of each layer of material, changes the resonance frequency of the resonator under the condition of not reducing the thickness of each layer of material, more easily matches the resonance frequency, realizes the integration of the duplexer and reduces the size of the duplexer. Under the condition of not changing the thickness of each layer of thin film, the process difficulty is reduced, and the monolithic integration and miniaturization of the duplexer can be realized.

Drawings

Fig. 1 is a block diagram of a duplexer of embodiment 1 of the present invention;

fig. 2 is a topology structure diagram of a duplexer transmitting end (receiving end) band pass filter according to embodiment 1 of the present invention;

fig. 3 is a cross-sectional view of a duplexer of embodiment 1 of the present invention;

fig. 4 is a cross-sectional view of a duplexer transmitting end (receiving end) band-pass filter according to embodiment 1 of the present invention.

Fig. 5 is a cross-sectional view of a stacked bulk acoustic wave resonator according to embodiment 1 of the present invention;

fig. 6 is a cross-sectional view of a duplexer transmitting terminal (receiving terminal) band-pass filter according to embodiment 2 of the present invention;

fig. 7 is a graph of impedance curves of stacked bulk acoustic wave resonators with different stacked layers according to embodiment 1 of the present invention;

101-antenna, 102-phase shifter, 103-transmitting end band-pass filter, 104-receiving end band-pass filter, 105-series bulk acoustic wave resonator, 106-parallel bulk acoustic wave resonator, 110-duplexer, 201-substrate, 202-acoustic reflection layer, 203-bottom electrode, 204-first piezoelectric material layer, 205-first middle electrode layer, 206-second piezoelectric material layer, 207-top electrode, 208-second middle electrode layer, 209-third piezoelectric material layer, 210-two-layer piezoelectric layer stacked bulk acoustic wave resonator, 211-third middle electrode layer, 212-fourth piezoelectric material layer, 220-three-layer piezoelectric layer stacked bulk acoustic wave resonator, 230-four-layer piezoelectric layer stacked bulk acoustic wave resonator.

Detailed Description

The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the following embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

It should be noted that the embodiments and features of the embodiments may be combined with each other without conflict.

The present invention is further illustrated by the following examples, which are not to be construed as limiting the invention.

The stacked bulk acoustic wave resonators can form a multi-layer piezoelectric oscillation stack series structure through the piezoelectric material layers and the electrode layers, the resonant frequency of the resonators can be improved, the stacked layers of the stacked bulk acoustic wave resonators are adjusted, the resonant frequency of a single resonator is subjected to frequency modulation, the resonant frequencies of the resonators of the receiving filter and the transmitting filter are matched, and therefore the integration of the duplexer is achieved.

The present embodiment is implemented by the following technical solution, a duplexer, including a substrate, and a receiving end filter and a transmitting end filter located on the substrate; the receiving-end filter and the transmitting-end filter each include a plurality of stacked bulk acoustic wave resonators. The stacked bulk acoustic wave resonator includes a substrate, an acoustic reflection layer, a bottom electrode, a plurality of piezoelectric material layers, a plurality of intermediate electrode layers, and a top electrode.

The number of the piezoelectric material layers of the stacked bulk acoustic wave resonator is at least two.

Different stacked bulk acoustic wave resonators have different numbers of piezoelectric material layers and intermediate electrode layers.

The acoustic reflection layer can be air or a Bragg reflection layer or a phononic crystal structure which is formed by alternately high-acoustic-impedance materials and low-acoustic-impedance materials.

The substrate is a non-flexible substrate and is suitable for the bulk acoustic wave resonator, and any one of a silicon substrate, a silicon carbide substrate, a sapphire substrate or an SOI substrate is selected.

Example 1: as shown in fig. 1, a block diagram of a duplexer 110 disclosed in embodiment 1 can isolate a transmission signal from a reception signal, and ensure that both reception and transmission can operate normally at the same time, and the duplexer includes a 101-antenna, a 102-phase shifter, a transmission port filter 103 and a reception port filter 104 of different frequency bands.

As shown in fig. 2, a block diagram of a bandpass filter of stacked bulk acoustic wave resonators. The filter is composed of a series bulk acoustic wave resonator 105 and a parallel bulk acoustic wave resonator 106, the filter is a first-order L-type topology structure, and meanwhile, the number of the series resonators and the number of the parallel resonators can be increased to form band-pass filters with different topological structures of different orders, and this embodiment 1 takes the first-order L-type topology structure as an example.

Fig. 3 is a cross-sectional view of the duplexer in example 1. Fig. 4 is a cross-sectional view of a transmitting end (receiving end) band-pass filter in the duplexer in this embodiment 1, which includes a substrate 201, an acoustic reflection layer 202, and a bottom electrode 203, a first piezoelectric material layer 204, a first intermediate electrode layer 205, a second piezoelectric material layer 206, a second intermediate electrode layer 208, a third piezoelectric material layer 209, and a top electrode 207 sequentially disposed on the substrate 201 and the acoustic reflection layer 202.

The stacked bulk acoustic wave resonators that make up the bandpass filter may be made up of any number of layers of piezoelectric material, with example 1 being 2, 3, 4 layers of piezoelectric material.

The piezoelectric material layer may have piezoelectric properties of one or a combination of aluminum nitride, zinc oxide, lithium niobate, PZT, and barium sodium niobate, and in this embodiment 1, aluminum nitride is taken as an example.

The bottom electrode, the top electrode, and the middle electrode layer are metal electrodes, and may be one or a combination of molybdenum, platinum, gold, silver, aluminum, tungsten, titanium, copper, ruthenium, and chromium, in which the molybdenum electrode is taken as an example in this embodiment 1.

As shown in fig. 5, which is a cross-sectional view of a 4-layer piezoelectric material layer stacked bulk acoustic wave resonator, the 4-layer piezoelectric material layer stacked bulk acoustic wave resonator includes a substrate base 201, an acoustic reflection layer 202, and a bottom electrode 203, a first piezoelectric material layer 204, a first intermediate electrode layer 205, a second piezoelectric material layer 206, a second intermediate electrode layer 208, a third piezoelectric material layer 209, a third intermediate electrode layer 211, a fourth piezoelectric material layer 212, and a top electrode 207 on the substrate base 201 and the acoustic reflection layer 202 in this order.

Example 2: as shown in fig. 6, a cross-sectional view of a filter having a bragg reflector as the acoustic reflector 202 is shown.

As shown in fig. 7, the impedance curve of the 2, 3, and 4-layer stacked bulk acoustic wave resonator is shown, and it can be seen from the diagram that the resonant frequency of the resonator is gradually increased along with the increase of the number of stacked layers without changing the layer thickness of each layer, and for the current increasingly higher frequency band requirement, this embodiment can achieve frequency increase without changing the thickness of the piezoelectric thin film layer, and also achieve matching of the resonant frequency more easily in the process of constructing the duplexer, and reduce the difficulty of the processing process.

While the invention has been described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the invention.