Radio frequency front end with different operating frequencies

Abstract

The invention provides a radio frequency front end with different working frequencies, which comprises a substrate, a first bulk acoustic wave resonator and a second bulk acoustic wave resonator, and is characterized in that the first bulk acoustic wave resonator is positioned above the substrate and comprises a first bottom electrode, a first piezoelectric layer and a first top electrode which are arranged from bottom to top; the first piezoelectric layer comprises at least two first piezoelectric film layers, and the polarities of the adjacent first piezoelectric film layers are the same; the second bulk acoustic wave resonator is located above the substrate, the second bulk acoustic wave resonator comprises a second bottom electrode, a second piezoelectric layer and a second top electrode which are arranged from bottom to top, the second piezoelectric layer comprises at least two second piezoelectric film layers, and the polarities of the adjacent second piezoelectric film layers are opposite. The first-order resonance is excited by the first bulk acoustic wave resonator, the high-order resonance is excited by the second bulk acoustic wave resonator, and the first-order resonance and the second-order resonance are different in working frequency, so that the radio frequency front end can work in different frequency bands at the same time, and the application requirements of different frequency bands are met.

Description

Technical Field

[0001] This invention belongs to the field of microelectronics technology and relates to a radio frequency front-end with different operating frequencies. Background Technology

[0002] Wireless data transmission requires radio frequency (RF) filters with operating frequencies of 5 GHz or higher. The filters used in 5G communication are mainly bulk acoustic wave (BAW) filters and surface acoustic wave (SAW) filters. BAW devices offer advantages such as high operating frequency, low insertion loss, high frequency selectivity, high power capacity, and strong electrostatic discharge (ESD) immunity, making them the best solution for future RF front-ends.

[0003] Currently, 5G communication commonly uses the sub-6GHz (3.3-4.2GHz) frequency band. With increasing application demands, microwave acoustics not only needs to expand its operating frequency but also needs to meet the requirements of ultra-wideband applications. Existing RF front-end resonators use single-layer piezoelectric materials, which operate at a limited frequency and can only meet the application needs of a specific frequency band, resulting in significant application limitations.

[0004] Therefore, how to provide a radio frequency front-end with different operating frequencies to meet the application needs of different frequency bands has become a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0005] In view of the shortcomings of the prior art described above, the purpose of this invention is to provide a radio frequency front-end with different operating frequencies to solve the problem that the operating frequency of the existing radio frequency front-end is limited and its application is restricted.

[0006] To achieve the above and other related objectives, the present invention provides a radio frequency front-end with different operating frequencies, comprising:

[0007] Substrate;

[0008] A first bulk acoustic wave resonator is located above the substrate. The first bulk acoustic wave resonator includes a first bottom electrode, a first piezoelectric layer and a first top electrode arranged from bottom to top. The first piezoelectric layer includes at least two first piezoelectric thin film layers, and adjacent first piezoelectric thin film layers have the same polarity.

[0009] The second bulk acoustic resonator is located above the substrate. The second bulk acoustic resonator includes a second bottom electrode, a second piezoelectric layer and a second top electrode arranged from bottom to top. The second piezoelectric layer includes at least two second piezoelectric thin film layers with opposite polarities for adjacent second piezoelectric thin film layers.

[0010] The operating frequency of the first bulk acoustic resonator is lower than that of the second bulk acoustic resonator.

[0011] Optionally, a first air cavity is provided between the first bottom electrode and the substrate, and a second air cavity is provided between the second bottom electrode and the substrate.

[0012] Optionally, a first Bragg reflection structure is provided between the first bottom electrode and the substrate, and a second Bragg reflection structure is provided between the second bottom electrode and the substrate.

[0013] Optionally, it further includes a bonding layer located between the bulk acoustic wave resonator and the substrate, a first air cavity being provided between the first bottom electrode and the bonding layer, and a second air cavity being provided between the second bottom electrode and the bonding layer.

[0014] Optionally, the interfaces of adjacent first piezoelectric thin film layers are in direct contact, and an interface modulation layer is disposed between adjacent second piezoelectric thin film layers. The material of the interface modulation layer includes one or more of TiN, Ti2O3, SiO2, SiC, SiN, AlN, Al2O3, AlON, SiON, HfO2, Mo, Mg, MgO, W, and Pt, and the thickness of the interface modulation layer ranges from 0.1 to 100 nm.

[0015] Optionally, the material of the first bottom electrode includes one or more of Au, Ag, Ru, W, Mo, Ir, Al, Pt, Nb, and Hf, and the thickness of the first bottom electrode does not exceed 0.3 μm. The material of the first top electrode includes one or more of Au, Ag, Ru, W, Mo, Ir, Al, Pt, Nb, and Hf, and the thickness of the first top electrode does not exceed 0.3 μm. The material of the first piezoelectric layer includes AlN and Al x Ga 1-x N(0 < x < 1), Al 1-x Sc x N(0<x<1), Ba x Sr 1-x The first piezoelectric layer is made of one or more of TiO3 (0 < x < 1), LiNbO3, ZnO, PZT, PbTiO3, and Ga2O3, and its thickness does not exceed 3 μm. The second bottom electrode is made of one or more of Au, Ag, Ru, W, Mo, Ir, Al, Pt, Nb, and Hf, and its thickness does not exceed 0.3 μm. The second top electrode is made of one or more of Au, Ag, Ru, W, Mo, Ir, Al, Pt, Nb, and Hf, and its thickness does not exceed 0.3 μm. The second piezoelectric layer is made of AlN, Al... x Ga1-x N(0 < x < 1), Al 1-x Sc x N(0<x<1), Ba x Sr 1-x The second piezoelectric layer is selected from one or more of TiO3 (0 < x < 1), LiNbO3, ZnO, PZT, PbTiO3, and Ga2O3, and the thickness of the second piezoelectric layer does not exceed 3 μm.

[0016] Optionally, the first bottom electrode uses a 100nm thick Mo metal layer, the first piezoelectric layer is composed of two 192nm thick N-polar AlN layers, the first top electrode uses a 100nm thick Mo metal layer, and the operating frequency of the first bulk acoustic wave resonator is in the WIFI6E band; the second bottom electrode uses a 100nm thick Mo metal layer, the second piezoelectric layer is composed of a 192nm thick N-polar AlN layer and a 192nm thick Al-polar AlN layer, the second top electrode uses a 100nm thick Mo metal layer, and the operating frequency of the second bulk acoustic wave resonator is in the Ku band.

[0017] Optionally, the first bottom electrode is a 100 nm thick Mo metal layer, and the first piezoelectric layer consists of a 198 nm thick AlN layer and a 198 nm thick Al layer. 0.7 Sc 0.3 The structure consists of N layers. The first top electrode is a 100nm thick Mo metal layer, and the operating frequency of the first bulk acoustic wave resonator is in the WIFI 6E band. The second bottom electrode is a 100nm thick Mo metal layer, and the second piezoelectric layer consists of a 198nm thick AlN layer and a 198nm thick Al layer. 0.7 Sc 0.3 The second top electrode is composed of an N-layer structure, and the second bulk acoustic resonator is made of a 100nm thick Mo metal layer. The operating frequency of the second bulk acoustic resonator is in the Ku band.

[0018] Optionally, the first bottom electrode is a 100 nm thick Mo metal layer, and the first piezoelectric layer consists of a 336 nm thick AlN layer and a 336 nm thick Al layer. 0.7 Sc 0.3 The structure consists of N layers. The first top electrode is a 100nm thick Mo metal layer, and the operating frequency of the first bulk acoustic resonator is in the N79 band. The second bottom electrode is a 100nm thick Mo metal layer, and the second piezoelectric layer consists of a 336nm thick AlN layer and a 336nm thick Al layer. 0.7 Sc 0.3 The second top electrode is composed of an N-layer structure, and the second bulk acoustic resonator is made of a 100nm thick Mo metal layer. The operating frequency of the second bulk acoustic resonator is in the X-wave band.

[0019] Optionally, the first bottom electrode is a 100 nm thick Mo metal layer, and the first piezoelectric layer consists of a 418 nm thick AlN layer and a 418 nm thick Al layer. 0.7 Sc 0.3 The structure consists of N layers. The first top electrode is a 100nm thick Mo metal layer, and the operating frequency of the first bulk acoustic resonator is in the N77 band. The second bottom electrode is a 100nm thick Mo metal layer, and the second piezoelectric layer consists of a 418nm thick AlN layer and a 418nm thick Al layer. 0.7 Sc 0.3 The second top electrode is composed of an N-layer structure, and the second bulk acoustic resonator is made of a 100nm thick Mo metal layer. The operating frequency of the second bulk acoustic resonator is in the UWB band.

[0020] Optionally, the first bottom electrode is a 100 nm thick Mo metal layer, and the first piezoelectric layer consists of a 785 nm thick AlN layer and a 785 nm thick Al layer. 0.7 Sc 0.3 The structure consists of N layers. The first top electrode is a 100nm thick Mo metal layer, and the operating frequency of the first bulk acoustic resonator is in the N41 band. The second bottom electrode is a 100nm thick Mo metal layer, and the second piezoelectric layer consists of a 785nm thick AlN layer and a 785nm thick Al layer. 0.7 Sc 0.3 The second top electrode is composed of an N-layer structure, and the second bulk acoustic resonator is made of a 100nm thick Mo metal layer. The operating frequency of the second bulk acoustic resonator is in the WIFI6 band.

[0021] Optionally, the first bottom electrode is a 100 nm thick Mo metal layer, and the first piezoelectric layer consists of a 1284 nm thick AlN layer and a 1284 nm thick Al layer. 0.7 Sc 0.3 The system consists of N layers. The first top electrode is a 100nm thick Mo metal layer, and the operating frequency of the first bulk acoustic resonator is in the N3 band. The second bottom electrode is a 100nm thick Mo metal layer, and the second piezoelectric layer consists of a 1284nm thick AlN layer and a 1284nm thick Al layer. 0.7 Sc 0.3 The second top electrode is composed of an N-layer structure, and the second bulk acoustic resonator is made of a 100nm thick Mo metal layer. The operating frequency of the second bulk acoustic resonator is in the N77 frequency band.

[0022] Optionally, the first bottom electrode is a 100 nm thick Mo metal layer, and the first piezoelectric layer consists of an 1164 nm thick AlN layer and an 1164 nm thick Al layer. 0.7 Sc 0.3The structure consists of N layers. The first top electrode is a 100nm thick Mo metal layer, and the operating frequency of the first bulk acoustic resonator is in the N2 band. The second bottom electrode is a 100nm thick Mo metal layer, and the second piezoelectric layer consists of an 1164nm thick AlN layer and an 1164nm thick Al layer. 0.7 Sc 0.3 The second top electrode is composed of an N-layer structure, and the second bulk acoustic resonator is made of a 100nm thick Mo metal layer. The operating frequency of the second bulk acoustic resonator is in the N77 frequency band.

[0023] Optionally, the first bottom electrode is a 100 nm thick Mo metal layer, and the first piezoelectric layer consists of an 1112 nm thick AlN layer and an 1112 nm thick Al layer. 0.7 Sc 0.3 The structure consists of N layers. The first top electrode is a 100nm thick Mo metal layer, and the operating frequency of the first bulk acoustic resonator is in the N1 band. The second bottom electrode is a 100nm thick Mo metal layer, and the second piezoelectric layer consists of an 1112nm thick AlN layer and an 1112nm thick Al layer. 0.7 Sc 0.3 The second top electrode is composed of an N-layer structure, and the second bulk acoustic resonator is made of a 100nm thick Mo metal layer. The operating frequency of the second bulk acoustic resonator is in the N77 frequency band.

[0024] As described above, the radio frequency front-end of the present invention with different operating frequencies includes a first bulk acoustic wave resonator and a second bulk acoustic wave resonator. The adjacent piezoelectric thin film layers in the first bulk acoustic wave resonator have the same polarity, which excites a first-order resonance. The adjacent piezoelectric thin film layers in the second bulk acoustic wave resonator have opposite polarities, which excite a higher-order resonance. The two have different operating frequencies, which allows the radio frequency front-end to work in different frequency bands at the same time, so as to meet the application requirements of different frequency bands. Attached Figure Description

[0025] Figure 1 The diagram shows a schematic of a radio frequency front-end with different operating frequencies in Embodiment 1 of the present invention.

[0026] Figure 2 The image shown is a simulation result diagram of Embodiment 1 of the present invention.

[0027] Figure 3 The figure shown is a simulation result diagram of the first body acoustic resonator in Embodiment 2 of the present invention.

[0028] Figure 4 The diagram shown is a simulation result of the second body acoustic resonator in Embodiment 2 of the present invention.

[0029] Figure 5 The figure shown is a simulation result diagram of the first body acoustic resonator in Embodiment 3 of the present invention.

[0030] Figure 6 The figure shown is a simulation result diagram of the second body acoustic resonator in Embodiment 3 of the present invention.

[0031] Figure 7 The figure shown is a simulation result diagram of the first bulk acoustic resonator in Embodiment 4 of the present invention.

[0032] Figure 8 The figure shown is a simulation result diagram of the second body acoustic resonator in Embodiment 4 of the present invention.

[0033] Figure 9 The figure shown is a simulation result diagram of the first bulk acoustic resonator in Embodiment 5 of the present invention.

[0034] Figure 10 The figure shown is a simulation result diagram of the second body acoustic resonator in Embodiment 5 of the present invention.

[0035] Figure 11 The figure shown is a simulation result diagram of the first bulk acoustic resonator in Embodiment Six of the present invention.

[0036] Figure 12 The figure shown is a simulation result diagram of the second body acoustic resonator in Embodiment 6 of the present invention.

[0037] Figure 13 The figure shown is a simulation result diagram of the first bulk acoustic resonator in Embodiment 7 of the present invention.

[0038] Figure 14 The figure shown is a simulation result diagram of the second body acoustic resonator in Embodiment 7 of the present invention.

[0039] Component designation explanation

[0040] 1 Substrate

[0041] 2 Bonding layer

[0042] 3 First air cavity

[0043] 4 Second air cavity

[0044] 5 First-body acoustic resonator

[0045] 50 First bottom electrode

[0046] 51 First piezoelectric layer

[0047] 510 Lower layer first piezoelectric thin film layer

[0048] 511 Upper First Piezoelectric Thin Film Layer

[0049] 52 First top electrode

[0050] 6 Second-body acoustic resonator

[0051] 60 Second bottom electrode

[0052] 61 Second piezoelectric layer

[0053] 610 Lower layer second piezoelectric thin film layer

[0054] 611 Upper Second Piezoelectric Thin Film Layer

[0055] 62 Second top electrode Detailed Implementation

[0056] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0057] Please see Figures 1 to 14 It should be noted that the illustrations provided in this embodiment are only schematic representations of the basic concept of the present invention. Therefore, the drawings only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0058] Example 1

[0059] This embodiment provides an RF front-end with different operating frequencies. Please refer to [link / reference]. Figure 1 The radio frequency front-end with different operating frequencies includes a substrate 1, a first bulk acoustic wave resonator 5, and a second bulk acoustic wave resonator 6. The first bulk acoustic wave resonator 5 is located above the substrate 1 and includes a first bottom electrode 50, a first piezoelectric layer 51, and a first top electrode 52 arranged from bottom to top. The first piezoelectric layer 51 includes at least two layers of first piezoelectric thin film, and adjacent first piezoelectric thin film layers have the same polarity. The second bulk acoustic wave resonator 6 is located above the substrate 1 and includes a second bottom electrode 60, a second piezoelectric layer 61, and a second top electrode 62 arranged from bottom to top. The second piezoelectric layer 61 includes at least two layers of second piezoelectric thin film, and adjacent second piezoelectric thin film layers have opposite polarities. The operating frequency of the first bulk acoustic wave resonator 5 is lower than the operating frequency of the second bulk acoustic wave resonator 6.

[0060] As an example, the substrate 1 includes a Si substrate, a SiC substrate, a Ge substrate, a sapphire substrate, or any other suitable substrate.

[0061] As an example, a bonding layer 2 is disposed between the substrate 1 and the bulk acoustic resonator, and the bonding layer 2 is also located between the first bottom electrode 50 and the second bottom electrode 60. The material of the bonding layer 2 includes dielectric materials such as SiO2 and Si3N4 or polymer materials such as PI (polyimide) and BCB (benzocyclobutene), which are selected according to requirements.

[0062] As an example, in the first bulk acoustic wave resonator 5, the overlapping area of ​​the first bottom electrode 50, the first piezoelectric layer 51, and the first top electrode 52 constitutes the resonant region of the first bulk acoustic wave resonator 5. A first air cavity 3 is provided between the first bottom electrode 50 and the bonding layer 2. The size of the first air cavity 3 is larger than the size of the resonant region of the first bulk acoustic wave resonator 5. The first air cavity 3 acts as an acoustic mirror to confine the sound waves of the first bulk acoustic wave resonator 5 within the first piezoelectric layer 51, preventing sound waves from leaking into the substrate 1, thereby reducing energy loss and helping to achieve a high Q value and low insertion loss.

[0063] As an example, the material of the first bottom electrode 50 includes one or more of Au, Ag, Ru, W, Mo, Ir, Al, Pt, Nb, and Hf, and the thickness of the first bottom electrode 50 does not exceed 0.3 μm.

[0064] As an example, the first piezoelectric layer 51 includes a lower first piezoelectric thin film layer 510 and an upper first piezoelectric thin film layer 511. The interfaces of the lower first piezoelectric thin film layer 510 and the upper first piezoelectric thin film layer 511 are in direct contact, and the lower first piezoelectric thin film layer 510 and the upper first piezoelectric thin film layer 511 have the same polarity (the arrows in the figure indicate the polarization direction, and the same polarity means the same polarization direction); wherein, the material of the first piezoelectric layer 51 includes AlN, Al x Ga 1-x N(0 < x < 1), Al 1-x Sc x N(0<x<1), Ba x Sr 1-x The first piezoelectric layer 51 is selected from one or more of TiO3 (0 < x < 1), LiNbO3, ZnO, PZT, PbTiO3, and Ga2O3, and its thickness does not exceed 3 μm.

[0065] As an example, the material of the first top electrode 52 includes one or more of Au, Ag, Ru, W, Mo, Ir, Al, Pt, Nb, and Hf, and the thickness of the first top electrode 52 does not exceed 0.3 μm.

[0066] As an example, in the first bulk acoustic resonator 5, adjacent first piezoelectric thin film layers in the first piezoelectric layer 51 have the same polarity, which excites the first-order resonance of the basis.

[0067] As an example, in the second bulk acoustic wave resonator 6, the overlapping area of ​​the second bottom electrode 60, the second piezoelectric layer 61, and the second top electrode 62 constitutes the resonant region of the second bulk acoustic wave resonator 6. A second air cavity 4 is provided between the second bottom electrode 60 and the bonding layer 2. The size of the second air cavity 4 is larger than the size of the resonant region of the second bulk acoustic wave resonator 6. The second air cavity 4 acts as an acoustic mirror to confine the sound waves of the second bulk acoustic wave resonator 6 within the second piezoelectric layer 61, preventing sound waves from leaking into the substrate 1, thereby reducing energy loss and helping to achieve a high Q value and low insertion loss.

[0068] As an example, the material of the second bottom electrode 60 includes one or more of Au, Ag, Ru, W, Mo, Ir, Al, Pt, Nb, and Hf, and the thickness of the second bottom electrode 60 does not exceed 0.3 μm.

[0069] As an example, the second piezoelectric layer 61 includes a lower second piezoelectric thin film layer 610 and an upper second piezoelectric thin film layer 611. An interface modulation layer 612 is disposed between the lower second piezoelectric thin film layer 610 and the upper second second piezoelectric thin film layer 611. The interface modulation layer 612 facilitates changing the surface chemical bond state of the lower second piezoelectric thin film layer 610, so that the polarities of the upper second piezoelectric thin film layer 611 and the lower second second piezoelectric thin film layer 610 are opposite (the arrows in the figure indicate the polarization direction, and opposite polarities indicate opposite polarization directions).

[0070] As an example, the material of the interface modulation layer 612 includes one or more of TiN, Ti2O3, SiO2, SiC, SiN, AlN, Al2O3, AlON, SiON, HfO2, Mo, Mg, MgO, W, and Pt, and the thickness of the interface modulation layer 612 ranges from 0.1 to 100 nm, preferably from 2 to 5 nm. The material of the second piezoelectric layer 61 includes AlN, Al... x Ga 1-x N(0 < x < 1), Al 1-x Sc x N(0<x<1), Ba x Sr 1-x The second piezoelectric layer 61 is selected from one or more of TiO3 (0 < x < 1), LiNbO3, ZnO, PZT, PbTiO3, and Ga2O3, and the thickness of the second piezoelectric layer 61 does not exceed 3 μm.

[0071] As an example, the second piezoelectric layer 61 and the first piezoelectric layer 61 have the same thickness. Preferably, the lower first piezoelectric thin film layer 510 and the lower second piezoelectric thin film layer 610 are formed in the same process, then the interface modulation layer 612 is formed, and then the upper first piezoelectric thin film layer 511 and the upper second piezoelectric thin film layer 611 are formed in the same process. Due to the presence of the interface modulation layer 612, the surface chemical bond state of the lower second piezoelectric thin film layer 610 is changed, so that the polarities of the upper second piezoelectric thin film layer 611 and the lower second piezoelectric thin film layer 610 are opposite, while the interfaces of the upper first piezoelectric thin film layer 511 and the lower first piezoelectric thin film layer 510 are in direct contact, and their polarities are the same.

[0072] As an example, the material of the second top electrode 62 includes one or more of Au, Ag, Ru, W, Mo, Ir, Al, Pt, Nb, and Hf, and the thickness of the second top electrode 62 does not exceed 0.3 μm.

[0073] As an example, in the second bulk acoustic resonator 6, the adjacent second piezoelectric thin film layers in the second piezoelectric layer 61 have opposite polarities and a 180° phase difference in the piezoelectric response to the electrical signal. The inverse piezoelectric effect causes one of the adjacent second piezoelectric thin film layers to be subjected to compressive stress and the other to be subjected to tensile stress, which suppresses the first-order resonance and excites higher-order resonances with higher frequencies.

[0074] As an example, in another example, the bonding layer 2 is not provided between the bulk acoustic resonator and the substrate 1, and the first air cavity 3 is provided between the first bottom electrode 50 and the substrate 1, and the second air cavity 4 is provided between the second bottom electrode 60 and the substrate 1, which also falls within the scope of protection of this invention; or a first Bragg reflection structure is provided between the first bottom electrode 50 and the substrate 1 as an acoustic mirror, and a second Bragg reflection structure is provided between the second bottom electrode 60 and the substrate 1 as an acoustic mirror, wherein the Bragg reflection structure includes a stacked high acoustic impedance material layer and a low acoustic impedance material layer, the material of the high acoustic impedance material layer includes one or more of W, Mo, Pt, Au, Ni and Ir, and the material of the low acoustic impedance material layer includes one or more of AlN, Si3N4 and SiO2, and the thickness of each layer is 1 / 4 or 3 / 4 of the wavelength of the sound wave corresponding to the resonant frequency of the resonator.

[0075] Specifically, in this embodiment, the first bottom electrode 50 uses a 100nm thick Mo metal layer, the lower first piezoelectric thin film layer 510 uses a 192nm thick N-polar AlN layer, the upper first piezoelectric thin film layer 511 uses a 192nm thick N-polar AlN layer, and the first top electrode 52 uses a 100nm thick Mo metal layer; the second bottom electrode 60 uses a 100nm thick Mo metal layer, the lower second piezoelectric thin film layer 610 uses a 192nm thick N-polar AlN layer, the upper second piezoelectric thin film layer 611 uses a 192nm thick Al-polar AlN layer, and the second top electrode 62 uses a 100nm thick Mo metal layer. Please refer to [link to previous text]. Figure 2 The figure shown is a simulation result diagram of Embodiment 1 of the present invention. The operating frequency of the first bulk acoustic resonator is 6.15 GHz, which is located in the WIFI6E band (5.925-7.125 GHz); the operating frequency of the second bulk acoustic resonator is 14.8 GHz, which is located in the Ku band (12-18 GHz), which can meet the application requirements of different frequency bands.

[0076] In other examples, by adjusting the electrode material and thickness, as well as the piezoelectric layer material and thickness, it is also possible to make the operating frequencies of the RF front-ends with different operating frequencies operate in the WIFI 6E band and the Ku band. For example, the first bottom electrode 50 can be made of a 100nm thick Mo metal layer, the lower first piezoelectric thin film layer 510 can be made of a 198nm thick AlN layer, and the upper first piezoelectric thin film layer 511 can be made of a 198nm thick AlN layer. 0.7 Sc 0.3 The first top electrode 52 is a 100nm thick Mo metal layer, and the operating frequency of the first bulk acoustic wave resonator is in the WIFI 6E band; the second bottom electrode 60 is a 100nm thick Mo metal layer, the lower second piezoelectric thin film layer 610 is a 198nm thick AlN layer, and the upper second piezoelectric thin film layer 611 is a 198nm thick AlN layer. 0.7 Sc 0.3 The N-layer, the second top electrode 62 is made of a 100nm thick Mo metal layer, and the operating frequency of the second bulk acoustic resonator is in the Ku band.

[0077] As described above, in the RF front-end with different operating frequencies in this embodiment, the first bulk acoustic resonator excites a first-order resonance, and the second bulk acoustic resonator excites a higher-order resonance. The two operate at different frequencies, which allows the RF front-end to operate simultaneously in the WIFI6E band and the Ku band to meet the application requirements of different frequency bands.

[0078] Example 2

[0079] The difference between this embodiment and Embodiment 1 is that: the first bottom electrode 50 is made of a 100nm thick Mo metal layer, the lower first piezoelectric thin film layer 510 is made of a 336nm thick AlN layer, and the upper first piezoelectric thin film layer 511 is made of a 336nm thick AlN layer. 0.7 Sc 0.3 The N-layer consists of a first top electrode 52 made of a 100 nm thick Mo metal layer; a second bottom electrode 60 made of a 100 nm thick Mo metal layer; a lower second piezoelectric thin film layer 610 made of a 336 nm thick AlN layer; and an upper second piezoelectric thin film layer 611 made of a 336 nm thick AlN layer. 0.7 Sc 0.3 The N-layer, and the second top electrode 62, are made of a 100 nm thick Mo metal layer. See also... Figure 3 and Figure 4 The first bulk acoustic resonator operates at a frequency of 4.5 GHz, and the second bulk acoustic resonator operates at a frequency of 10 GHz, enabling the RF front-end to operate simultaneously in the N79 band (4.4-5 GHz) and the X-band (8-12 GHz) to meet the application requirements of different frequency bands.

[0080] Example 3

[0081] The difference between this embodiment and Embodiment 1 is that: the first bottom electrode 50 is a 100nm thick Mo metal layer, the lower first piezoelectric thin film layer 510 is a 418nm thick AlN layer, and the upper first piezoelectric thin film layer 511 is a 418nm thick AlN layer. 0.7 Sc 0.3 The N-layer consists of a first top electrode 52 made of a 100 nm thick Mo metal layer; a second bottom electrode 60 made of a 100 nm thick Mo metal layer; a lower second piezoelectric thin film layer 610 made of a 418 nm thick AlN layer; and an upper second piezoelectric thin film layer 611 made of a 418 nm thick AlN layer. 0.7 Sc 0.3 The N-layer, and the second top electrode 62, are made of a 100 nm thick Mo metal layer. See also... Figure 5 and Figure 6 The first bulk acoustic resonator operates at a frequency of 3.53 GHz, and the second bulk acoustic resonator operates at a frequency of 7.53 GHz, enabling the RF front-end to operate simultaneously in the N77 band (3.3-4.2 GHz) and the UWB band (7.163-8.812 GHz) to meet the application requirements of different frequency bands.

[0082] Example 4

[0083] The difference between this embodiment and Embodiment 1 is that: the first bottom electrode 50 is a 100nm thick Mo metal layer, the lower first piezoelectric thin film layer 510 is a 785nm thick AlN layer, and the upper first piezoelectric thin film layer 511 is a 785nm thick AlN layer. 0.7 Sc 0.3 The N-layer consists of a first top electrode 52 made of a 100 nm thick Mo metal layer; a second bottom electrode 60 made of a 100 nm thick Mo metal layer; a lower second piezoelectric thin film layer 610 made of a 785 nm thick AlN layer; and an upper second piezoelectric thin film layer 611 made of a 785 nm thick AlN layer. 0.7 Sc 0.3 The N-layer, and the second top electrode 62, are made of a 100 nm thick Mo metal layer. See also... Figure 7 and Figure 8 The first bulk acoustic resonator operates at a frequency of 2.61 GHz, and the second bulk acoustic resonator operates at a frequency of 5.4 GHz, enabling the RF front-end to operate simultaneously in the N41 band (2.496-2.69 GHz) and the WIFI6 band (5.15-5.85 GHz) to meet the application requirements of different frequency bands.

[0084] Example 5

[0085] The difference between this embodiment and Embodiment 1 is that: the first bottom electrode 50 is made of a 100nm thick Mo metal layer, the lower first piezoelectric thin film layer 510 is made of a 1284nm thick AlN layer, and the upper first piezoelectric thin film layer 511 is made of a 1284nm thick AlN layer. 0.7 Sc 0.3 The N-layer consists of a first top electrode 52 made of a 100 nm thick Mo metal layer; a second bottom electrode 60 made of a 100 nm thick Mo metal layer; a lower second piezoelectric thin film layer 610 made of a 1284 nm thick AlN layer; and an upper second piezoelectric thin film layer 611 made of a 1284 nm thick AlN layer. 0.7 Sc 0.3 The N-layer, and the second top electrode 62, are made of a 100 nm thick Mo metal layer. See also... Figure 9 and Figure 10 The first bulk acoustic resonator operates at a frequency of 1.73 GHz, and the second bulk acoustic resonator operates at a frequency of 3.51 GHz, enabling the RF front-end to operate simultaneously in the N3 band (1.710-1.785 GHz) and the N77 band (3.3-4.2 GHz) to meet the application requirements of different frequency bands.

[0086] Example 6

[0087] The difference between this embodiment and Embodiment 1 is that: the first bottom electrode 50 is made of a 100nm thick Mo metal layer, the lower first piezoelectric thin film layer 510 is made of an 1164nm thick AlN layer, and the upper first piezoelectric thin film layer 511 is made of an 1164nm thick AlN layer. 0.7 Sc 0.3 The N-layer consists of a first top electrode 52 made of a 100 nm thick Mo metal layer; a second bottom electrode 60 made of a 100 nm thick Mo metal layer; a lower second piezoelectric thin film layer 610 made of an 1164 nm thick AlN layer; and an upper second piezoelectric thin film layer 611 made of an 1164 nm thick AlN layer. 0.7 Sc 0.3 The N-layer, and the second top electrode 62, are made of a 100 nm thick Mo metal layer. See also... Figure 11 and Figure 12 The first bulk acoustic resonator operates at a frequency of 1.88 GHz, and the second bulk acoustic resonator operates at a frequency of 3.8 GHz, enabling the RF front-end to operate simultaneously in the N2 band (1.85-1.91 GHz) and the N77 band (3.3-4.2 GHz) to meet the application requirements of different frequency bands.

[0088] Example 7

[0089] The difference between this embodiment and Embodiment 1 is that: the first bottom electrode 50 is made of a 100nm thick Mo metal layer, the lower first piezoelectric thin film layer 510 is made of an 1112nm thick AlN layer, and the upper first piezoelectric thin film layer 511 is made of an 1112nm thick AlN layer. 0.7 Sc 0.3 The N-layer consists of a first top electrode 52 made of a 100 nm thick Mo metal layer; a second bottom electrode 60 made of a 100 nm thick Mo metal layer; a lower second piezoelectric thin film layer 610 made of an 1112 nm thick AlN layer; and an upper second piezoelectric thin film layer 611 made of an 1112 nm thick AlN layer. 0.7 Sc 0.3 The N-layer, and the second top electrode 62, are made of a 100 nm thick Mo metal layer. See also... Figure 13 and Figure 14 The first bulk acoustic resonator operates at a frequency of 1.95 GHz, and the second bulk acoustic resonator operates at a frequency of 3.96 GHz, enabling the RF front-end to operate simultaneously in the N1 band (2.496-2.69 GHz) and the N77 band (3.3-4.2 GHz) to meet the application requirements of different frequency bands.

[0090] It should be noted that the electrode material and thickness, as well as the piezoelectric layer material and thickness, can be adjusted to allow the RF front end to operate in other frequency bands simultaneously, depending on actual needs.

[0091] In summary, the radio frequency front-end of the present invention, which has different operating frequencies, includes a first bulk acoustic wave resonator and a second bulk acoustic wave resonator. In the first bulk acoustic wave resonator, adjacent piezoelectric thin film layers have the same polarity, exciting a first-order resonance. In the second bulk acoustic wave resonator, adjacent piezoelectric thin film layers have opposite polarities, exciting a higher-order resonance. The two resonators operate at different frequencies, allowing the radio frequency front-end to operate simultaneously in different frequency bands to meet the application requirements of different frequency bands. Therefore, the present invention effectively overcomes various shortcomings of the prior art and has high industrial applicability.

[0092] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A radio frequency front end with different operating frequencies, characterized in that, include: Substrate; A first bulk acoustic wave resonator is located above the substrate. The first bulk acoustic wave resonator includes a first bottom electrode, a first piezoelectric layer and a first top electrode arranged from bottom to top. The first piezoelectric layer includes at least two first piezoelectric thin film layers, and adjacent first piezoelectric thin film layers have the same polarity. The second bulk acoustic resonator is located above the substrate. The second bulk acoustic resonator includes a second bottom electrode, a second piezoelectric layer and a second top electrode arranged from bottom to top. The second piezoelectric layer includes at least two second piezoelectric thin film layers with opposite polarities for adjacent second piezoelectric thin film layers. The operating frequency of the first bulk acoustic resonator is lower than that of the second bulk acoustic resonator.

2. The radio frequency front end with different operating frequencies according to claim 1, characterized in that: A first air cavity is provided between the first bottom electrode and the substrate, and a second air cavity is provided between the second bottom electrode and the substrate.

3. The radio frequency front end with different operating frequencies according to claim 1, characterized in that: A first Bragg reflection structure is disposed between the first bottom electrode and the substrate, and a second Bragg reflection structure is disposed between the second bottom electrode and the substrate.

4. The radio frequency front end with different operating frequencies according to claim 1, characterized in that: It also includes a bonding layer located between the bulk acoustic wave resonator and the substrate, a first air cavity is provided between the first bottom electrode and the bonding layer, and a second air cavity is provided between the second bottom electrode and the bonding layer.

5. The radio frequency front end with different operating frequencies according to claim 1, characterized in that: The interfaces of adjacent first piezoelectric thin film layers are in direct contact, and an interface modulation layer is disposed between adjacent second piezoelectric thin film layers. The material of the interface modulation layer includes one or more of TiN, Ti2O3, SiO2, SiC, SiN, AlN, Al2O3, AlON, SiON, HfO2, Mo, Mg, MgO, W, and Pt, and the thickness of the interface modulation layer ranges from 0.1 to 100 nm.

6. The radio frequency front end with different operating frequencies according to claim 1, characterized in that: The first bottom electrode is made of one or more of Au, Ag, Ru, W, Mo, Ir, Al, Pt, Nb, and Hf, and its thickness does not exceed 0.3 μm. The first top electrode is made of one or more of Au, Ag, Ru, W, Mo, Ir, Al, Pt, Nb, and Hf, and its thickness does not exceed 0.3 μm. The first piezoelectric layer is made of AlN, Al... x Ga 1-x N(0 < x < 1), Al 1-x Sc x N(0<x<1), Ba x Sr 1-x The first piezoelectric layer is made of one or more of TiO3 (0 < x < 1), LiNbO3, ZnO, PZT, PbTiO3, and Ga2O3, and its thickness does not exceed 3 μm. The second bottom electrode is made of one or more of Au, Ag, Ru, W, Mo, Ir, Al, Pt, Nb, and Hf, and its thickness does not exceed 0.3 μm. The second top electrode is made of one or more of Au, Ag, Ru, W, Mo, Ir, Al, Pt, Nb, and Hf, and its thickness does not exceed 0.3 μm. The second piezoelectric layer is made of AlN, Al... x Ga 1-x N(0 < x < 1), Al 1-x Sc x N(0<x<1), Ba x Sr 1-x The second piezoelectric layer is selected from one or more of TiO3 (0 < x < 1), LiNbO3, ZnO, PZT, PbTiO3, and Ga2O3, and the thickness of the second piezoelectric layer does not exceed 3 μm.

7. The radio frequency front end with different operating frequencies according to claim 6, characterized in that: The first bottom electrode uses a 100nm thick Mo metal layer, the first piezoelectric layer is composed of two 192nm thick N-polar AlN layers, the first top electrode uses a 100nm thick Mo metal layer, and the operating frequency of the first bulk acoustic wave resonator is in the WIFI6E band; the second bottom electrode uses a 100nm thick Mo metal layer, the second piezoelectric layer is composed of a 192nm thick N-polar AlN layer and a 192nm thick Al-polar AlN layer, the second top electrode uses a 100nm thick Mo metal layer, and the operating frequency of the second bulk acoustic wave resonator is in the Ku band.

8. The radio frequency front end with different operating frequencies according to claim 6, characterized in that: The first bottom electrode uses a 100nm thick Mo metal layer, and the first piezoelectric layer consists of a 198nm thick AlN layer and a 198nm thick Al layer. 0.7 Sc 0.3 The structure consists of N layers. The first top electrode is a 100nm thick Mo metal layer, and the operating frequency of the first bulk acoustic wave resonator is in the WIFI 6E band. The second bottom electrode is a 100nm thick Mo metal layer, and the second piezoelectric layer consists of a 198nm thick AlN layer and a 198nm thick Al layer. 0.7 Sc 0.3 The second top electrode is composed of an N-layer structure, and the second bulk acoustic resonator is made of a 100nm thick Mo metal layer. The operating frequency of the second bulk acoustic resonator is in the Ku band.

9. The radio frequency front end with different operating frequencies according to claim 6, characterized in that: The first bottom electrode uses a 100nm thick Mo metal layer, and the first piezoelectric layer consists of a 336nm thick AlN layer and a 336nm thick Al layer. 0.7 Sc 0.3 The structure consists of N layers. The first top electrode is a 100nm thick Mo metal layer, and the operating frequency of the first bulk acoustic resonator is in the N79 band. The second bottom electrode is a 100nm thick Mo metal layer, and the second piezoelectric layer consists of a 336nm thick AlN layer and a 336nm thick Al layer. 0.7 Sc 0.3 The second top electrode is composed of an N-layer structure, and the second bulk acoustic resonator is made of a 100nm thick Mo metal layer. The operating frequency of the second bulk acoustic resonator is in the X-wave band.

10. The radio frequency front end with different operating frequencies according to claim 6, characterized in that: The first bottom electrode uses a 100nm thick Mo metal layer, and the first piezoelectric layer consists of a 418nm thick AlN layer and a 418nm thick Al layer. 0.7 Sc 0.3 The structure consists of N layers. The first top electrode is a 100nm thick Mo metal layer, and the operating frequency of the first bulk acoustic resonator is in the N77 band. The second bottom electrode is a 100nm thick Mo metal layer, and the second piezoelectric layer consists of a 418nm thick AlN layer and a 418nm thick Al layer. 0.7 Sc 0.3 The second top electrode is composed of an N-layer structure, and the second bulk acoustic resonator is made of a 100nm thick Mo metal layer. The operating frequency of the second bulk acoustic resonator is in the UWB band.

11. The radio frequency front end with different operating frequencies according to claim 6, characterized in that: The first bottom electrode uses a 100nm thick Mo metal layer, and the first piezoelectric layer consists of a 785nm thick AlN layer and a 785nm thick Al layer. 0.7 Sc 0.3 The structure consists of N layers. The first top electrode is a 100nm thick Mo metal layer, and the operating frequency of the first bulk acoustic resonator is in the N41 band. The second bottom electrode is a 100nm thick Mo metal layer, and the second piezoelectric layer consists of a 785nm thick AlN layer and a 785nm thick Al layer. 0.7 Sc 0.3 The second top electrode is composed of an N-layer structure, and the second bulk acoustic resonator is made of a 100nm thick Mo metal layer. The operating frequency of the second bulk acoustic resonator is in the WIFI6 band.

12. The radio frequency front end with different operating frequencies according to claim 6, characterized in that: The first bottom electrode uses a 100nm thick Mo metal layer, and the first piezoelectric layer consists of a 1284nm thick AlN layer and a 1284nm thick Al layer. 0.7 Sc 0.3 The system consists of N layers. The first top electrode is a 100nm thick Mo metal layer, and the operating frequency of the first bulk acoustic resonator is in the N3 band. The second bottom electrode is a 100nm thick Mo metal layer, and the second piezoelectric layer consists of a 1284nm thick AlN layer and a 1284nm thick Al layer. 0.7 Sc 0.3 The second top electrode is composed of an N-layer structure, and the second bulk acoustic resonator is made of a 100nm thick Mo metal layer. The operating frequency of the second bulk acoustic resonator is in the N77 frequency band.

13. The radio frequency front end with different operating frequencies according to claim 6, characterized in that: The first bottom electrode uses a 100 nm thick Mo metal layer, and the first piezoelectric layer consists of an 1164 nm thick AlN layer and an 1164 nm thick Al layer. 0.7 Sc 0.3 The structure consists of N layers. The first top electrode is a 100nm thick Mo metal layer, and the operating frequency of the first bulk acoustic resonator is in the N2 band. The second bottom electrode is a 100nm thick Mo metal layer, and the second piezoelectric layer consists of an 1164nm thick AlN layer and an 1164nm thick Al layer. 0.7 Sc 0.3 The second top electrode is composed of an N-layer structure, and the second bulk acoustic resonator is made of a 100nm thick Mo metal layer. The operating frequency of the second bulk acoustic resonator is in the N77 frequency band.

14. The radio frequency front end with different operating frequencies according to claim 6, characterized in that: The first bottom electrode uses a 100 nm thick Mo metal layer, and the first piezoelectric layer consists of an 1112 nm thick AlN layer and an 1112 nm thick Al layer. 0.7 Sc 0.3 The structure consists of N layers. The first top electrode is a 100nm thick Mo metal layer, and the operating frequency of the first bulk acoustic resonator is in the N1 band. The second bottom electrode is a 100nm thick Mo metal layer, and the second piezoelectric layer consists of an 1112nm thick AlN layer and an 1112nm thick Al layer. 0.7 Sc 0.3 The second top electrode is composed of an N-layer structure, and the second bulk acoustic resonator is made of a 100nm thick Mo metal layer. The operating frequency of the second bulk acoustic resonator is in the N77 frequency band.

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