A duplexer and manufacturing method, electronic device

Abstract

The duplexers disclosed by the embodiments of the present application comprise a transmitting filter and a receiving filter formed on the same substrate, and the transmitting filter and the receiving filter comprise a plurality of film layers forming a laminated structure, wherein the piezoelectric layers of the transmitting filter and the receiving filter are doped with elements, and the longitudinal wave speed of the piezoelectric layer of the transmitting filter along the thickness direction is less than the longitudinal wave speed of the piezoelectric layer of the receiving filter along the thickness direction. The embodiments of the present application also disclose a manufacturing method of the duplexers and an electronic device. By making the longitudinal wave speed of the piezoelectric layer of the transmitting filter along the thickness direction less than the longitudinal wave speed of the piezoelectric layer of the receiving filter along the thickness direction, the power capacity of the transmitting filter is ensured, and the size is reduced and the cost is lowered as much as possible.

Description

Technical Field

[0001] This invention relates to the field of semiconductor technology, and more specifically, to a duplexer and its manufacturing method, and an electronic device. Background Technology

[0002] In communication systems, duplexers are used in FDD systems to enable simultaneous reception and transmission of signals. For example... Figure 1 and 2 As shown, in existing technologies, the transmit and receive filters in a duplexer are typically fabricated separately, diced, and then ball-mounted onto the two diced filters before being packaged separately on a substrate at a certain distance. This type of duplexer requires multiple packaging steps, resulting in a larger chip size and relatively higher cost. For example... Figure 3 As shown, in the prior art, surface acoustic wave devices are also integrated onto a substrate to form a duplexer. This method involves adjusting parameters such as the planar pattern and angle of the interdigitated electrodes (i.e., Figure 3 The size of 'a' in the middle can be used to achieve a larger frequency range adjustment. Summary of the Invention

[0003] To address the aforementioned problems, the present invention aims to provide a duplexer, its manufacturing method, and an electronic device, thereby reducing chip size and lowering costs.

[0004] This invention provides a duplexer, the duplexer comprising:

[0005] A transmitting filter and a receiving filter are formed on the same substrate, wherein the transmitting filter and the receiving filter comprise a stacked structure of multiple film layers.

[0006] Wherein, the piezoelectric layers of the transmitting filter and the receiving filter are doped with elements, and the longitudinal wave velocity along the thickness direction of the piezoelectric layer of the transmitting filter is less than the longitudinal wave velocity along the thickness direction of the piezoelectric layer of the receiving filter.

[0007] As a further improvement of the present invention, the piezoelectric layer of the transmitting filter and the piezoelectric layer of the receiving filter have the same doping elements but different doping concentrations, or...

[0008] The piezoelectric layer of the transmitting filter and the piezoelectric layer of the receiving filter have different doping elements.

[0009] As a further improvement of the present invention, the atomic fraction of the doping elements in the piezoelectric layer of the transmitting filter and the piezoelectric layer of the receiving filter ranges from 0% to 40%.

[0010] The atomic fraction of the doped elements in the piezoelectric layer of the transmitting filter is lower than the atomic fraction of the doped elements in the piezoelectric layer of the receiving filter.

[0011] As a further improvement of the present invention, the atomic fraction of the doped elements in the piezoelectric layer of the transmitting filter and the piezoelectric layer of the receiving filter ranges from 8% to 30%.

[0012] As a further improvement of the present invention, the transmitting filter includes a plurality of first resonators, and the receiving filter includes a plurality of second resonators.

[0013] The first resonator and the second resonator each include a piezoelectric layer, and the doping concentration of the piezoelectric layer of the first resonator is the same as that of the piezoelectric layer of the second resonator.

[0014] As a further improvement of the present invention, the transmitting filter includes a plurality of first resonators, and the receiving filter includes a plurality of second resonators.

[0015] The first resonator and the second resonator each include multiple piezoelectric layers. The piezoelectric layers of the first resonator have the same doping elements but different doping concentrations, and the piezoelectric layers of the second resonator have the same doping elements but different doping concentrations. The total doping concentration of the piezoelectric layers of the first resonator is less than that of the piezoelectric layers of the second resonator.

[0016] As a further improvement of the present invention, for the multilayer piezoelectric layer, the thickness of each piezoelectric layer is t1, t2, ..., tn, and the doping concentration of each piezoelectric layer is c1, c2, ..., cn, respectively. The total doping concentration of the piezoelectric layer is: (t1*c1+t2*c2+...+tn*cn) / (t1+t2+...+tn), where n is an integer greater than or equal to 2.

[0017] As a further improvement of the present invention, the transmitting filter includes a plurality of first resonators, and the receiving filter includes a plurality of second resonators.

[0018] The first resonator and the second resonator each include multiple piezoelectric layers. The doping elements of each piezoelectric layer of the first resonator are different, and the doping elements of each piezoelectric layer of the second resonator are different. The total equivalent longitudinal wave velocity of the piezoelectric layer of the first resonator is less than that of the piezoelectric layer of the second resonator.

[0019] As a further improvement of the present invention, for the multilayer piezoelectric layer, the thickness of each piezoelectric layer is t1, t2, ..., tn, and the longitudinal wave velocity of each piezoelectric layer is v1, v2, ..., vn, respectively. The total equivalent longitudinal wave velocity of the piezoelectric layer is: (t1*v1+t2*v2+...+tn*vn) / (t1+t2+...+tn), where n is an integer greater than or equal to 2.

[0020] As a further improvement of the present invention, the number of piezoelectric layers in the first resonator is different from the number of piezoelectric layers in the resonator.

[0021] As a further improvement of the present invention, at least one film layer in the first resonator has a thickness that is different from the thickness of the corresponding film layer in the second resonator.

[0022] As a further improvement of the present invention, the pad areas of the transmitting filter and / or the receiving filter are increased by at least one metal area.

[0023] As a further improvement of the present invention, the metal regions of the transmitting filter and the receiving filter extend toward their respective pin directions.

[0024] As a further improvement of the present invention, the piezoelectric layer of the transmitting filter and the piezoelectric layer of the receiving filter are made of aluminum nitride or doped aluminum nitride, wherein the doping element of the doped aluminum nitride is scandium.

[0025] This invention also provides a method for manufacturing a duplexer, the duplexer including a transmitting filter and a receiving filter, the transmitting filter and the receiving filter including a stacked structure formed of multiple film layers, the method including:

[0026] The transmitting filter and the receiving filter are formed on the same substrate, and elements are doped in the piezoelectric layer of the transmitting filter and the piezoelectric layer of the receiving filter so that the longitudinal wave velocity of the piezoelectric layer of the transmitting filter along the thickness direction is less than the longitudinal wave velocity of the piezoelectric layer of the receiving filter along the thickness direction.

[0027] As a further improvement of the present invention, the step of doping elements in the piezoelectric layer of the transmitting filter and the piezoelectric layer of the receiving filter, such that the longitudinal wave velocity along the thickness direction of the piezoelectric layer of the transmitting filter is less than the longitudinal wave velocity along the thickness direction of the piezoelectric layer of the receiving filter, includes:

[0028] The piezoelectric layers of the transmitting filter and the receiving filter are doped with the same element but at different concentrations, or...

[0029] Different elements are doped into the piezoelectric layer of the transmitting filter and the piezoelectric layer of the receiving filter.

[0030] As a further improvement of the present invention, the transmitting filter includes a plurality of first resonators, the receiving filter includes a plurality of second resonators, the first resonators and the second resonators each include a piezoelectric layer, and the method further includes:

[0031] Doping elements are performed on the piezoelectric layers of the first resonator and the second resonator, such that the doping concentration of a portion of the piezoelectric layer of the first resonator is the same as that of the piezoelectric layer of the second resonator.

[0032] As a further improvement of the present invention, the transmitting filter includes a plurality of first resonators, and the receiving filter includes a plurality of second resonators, wherein the first resonators and the second resonators each include multiple piezoelectric layers, and the method further includes:

[0033] The first resonator has piezoelectric layers doped with the same element but with different doping concentrations, and the second resonator has piezoelectric layers doped with the same element but with different doping concentrations, so that the total doping concentration of the piezoelectric layers in the first resonator is less than that in the second resonator.

[0034] As a further improvement of the present invention, the transmitting filter includes a plurality of first resonators, and the receiving filter includes a plurality of second resonators, wherein the first resonators and the second resonators each include multiple piezoelectric layers, and the method further includes:

[0035] Different elements are doped into each piezoelectric layer of the first resonator and into each piezoelectric layer of the second resonator, so that the total equivalent longitudinal wave velocity of the piezoelectric layer of the first resonator is less than that of the piezoelectric layer of the second resonator.

[0036] As a further improvement of the present invention, the method further includes:

[0037] By processing the film layers of the first resonator and / or the second resonator, the thickness of at least one film layer in the first resonator is different from the thickness of the corresponding film layer in the second resonator.

[0038] As a further improvement of the present invention, the method further includes:

[0039] At least one metal region is added to the pad area of ​​the transmitting filter and / or the receiving filter.

[0040] As a further improvement of the present invention, the at least one metal region extends in the direction of the pin.

[0041] This invention also provides an electronic device including the aforementioned duplexer.

[0042] The beneficial effects of this invention are as follows: by making the longitudinal wave velocity of the piezoelectric layer of the transmitting filter lower than that of the piezoelectric layer of the receiving filter, the power capacity of the transmitting filter is guaranteed, while the size and cost can be reduced as much as possible. Attached Figure Description

[0043] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0044] Figure 1 This is a schematic diagram of an existing duplexer;

[0045] Figure 2 for Figure 1 Cross-sectional view;

[0046] Figure 3 This is a schematic diagram of a duplexer that integrates surface acoustic wave devices onto the same substrate in the prior art;

[0047] Figure 4 This is a schematic diagram of a duplexer according to an exemplary embodiment of the present invention;

[0048] Figure 5 for Figure 4 Cross-sectional view;

[0049] Figure 6 This is a cross-sectional schematic diagram of a duplexer according to an exemplary embodiment of the present invention, showing that the piezoelectric layers of the transmitting filter and the receiving filter have different doping concentrations.

[0050] Figure 7 This is a cross-sectional schematic diagram of a duplexer according to an exemplary embodiment of the present invention, showing a piezoelectric layer with different doping concentrations;

[0051] Figure 8 This is a cross-sectional schematic diagram of a duplexer according to an exemplary embodiment of the present invention, showing that the doping concentrations of the multilayer piezoelectric layers are different;

[0052] Figure 9 A comparison diagram showing the isolation of an existing duplexer and a duplexer according to an exemplary embodiment of the present invention without adding a metal region;

[0053] Figure 10 A comparison diagram of the isolation levels of an existing duplexer and a duplexer according to an exemplary embodiment of the present invention after adding a metal region;

[0054] Figure 11 This is a schematic diagram of an exemplary embodiment of the present invention, showing an added metal region in a duplexer, wherein the added metal region in the transmit filter is illustrated.

[0055] Figure 12This is a schematic diagram of a duplexer with an added metal region, as described in another exemplary embodiment of the present invention, showing the added metal region of the transmit filter. Detailed Implementation

[0056] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0057] It should be noted that if the embodiments of the present invention involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicators will also change accordingly.

[0058] Furthermore, the terminology used in the description of this invention is for illustrative purposes only and is not intended to limit the scope of the invention. The terms "comprising" and / or "including" are used to specify the presence of said elements, steps, operations, and / or components, but do not exclude the presence or addition of one or more other elements, steps, operations, and / or components. The terms "first," "second," etc., may be used to describe various elements, do not represent an order, and do not limit these elements. Moreover, in the description of this invention, unless otherwise stated, "a plurality of" means two or more. These terms are used only to distinguish one element from another. These and / or other aspects become apparent in conjunction with the following drawings, and those skilled in the art will more readily understand the description of the embodiments of the invention. The drawings are used for illustrative purposes only to depict the embodiments of the invention. Those skilled in the art will readily recognize from the following description that alternative embodiments of the structures and methods shown in the invention can be employed without departing from the principles of the invention.

[0059] A duplexer as described in the embodiments of the present invention, such as Figure 4 and 5 As shown, the duplexer includes:

[0060] A transmitting filter and a receiving filter are formed on the same substrate, wherein the transmitting filter and the receiving filter comprise a stacked structure of multiple film layers.

[0061] Wherein, the piezoelectric layers of the transmitting filter and the receiving filter are doped with elements, and the longitudinal wave velocity of the piezoelectric layer of the transmitting filter along the thickness direction is less than that of the piezoelectric layer of the receiving filter along the thickness direction.

[0062] It is understood that a TX filter (transmitting filter) is a first-layer structure formed by multiple film layers on a substrate, and an RX filter (receiving filter) is a second-layer structure formed by multiple film layers on a substrate. The stacked structure of a filter (including the first and second stacked structures) generally includes a substrate, an acoustic mirror cavity, and multiple film layers formed on the substrate (e.g., bottom electrode, piezoelectric layer, and top electrode), but is not limited to these layers. It may also include one or more of the following film layers: a temperature compensation layer, a mass loading layer, a protective layer (passivation layer), and a sacrificial layer. For example, ... Figure 6 As shown, the duplexer includes a TX filter and an RX filter fabricated on the same substrate. The TX filter includes an acoustic mirror cavity, a bottom electrode BM_TX, a piezoelectric layer PZ_TX, and a top electrode TM_TX. The RX filter includes an acoustic mirror cavity, a bottom electrode BM_RX, a piezoelectric layer PZ_RX, and a top electrode TM_RX. The longitudinal wave velocity of the piezoelectric layer PZ_TX along the thickness direction is smaller than that of the piezoelectric layer PZ_RX along the thickness direction.

[0063] The TX and RX filters of the duplexer described in this invention are integrated on the same substrate, allowing the duplexer chip to be fabricated in a single process, followed by packaging on the substrate. Compared to... Figure 1 and 2 The existing duplexer shown involves fabricating each filter separately and then packaging them on a substrate. This invention reduces the number of packaging steps, and because the TX filter can share some structural elements with the RX filter, the overall chip size can be reduced, lowering costs. Furthermore, since the spacing between the TX and RX filters can be eliminated during the packaging process, the chip size can be further reduced.

[0064] Furthermore, this invention alters the characteristics of the piezoelectric layer of the filter by doping it with certain impurity elements, changing its dielectric constant, electromechanical coupling coefficient, and other properties. After doping, the electromechanical coupling coefficient increases; for the same electromechanical coupling coefficient, the piezoelectric layer can be thinner and its area smaller, thus reducing the filter size and saving costs. Generally, higher doping concentrations result in smaller resonator areas for the same impedance in the filter, requiring smaller resonator areas and thus a smaller overall filter size. However, smaller resonator areas lead to lower power handling capacity. For TX filters, the resonator area cannot be too small to meet certain power requirements. For RX filters, with lower power requirements, the area can be minimized. Doping causes the longitudinal wave velocity along the thickness direction of the piezoelectric layer to decrease with increasing concentration; different doping elements result in different velocity reduction processes. In the duplexer of this invention, the longitudinal wave velocity along the thickness direction of the TX filter piezoelectric layer is lower than that of the RX filter piezoelectric layer, allowing for minimizing chip area and cost while meeting power capacity requirements. The duplexer described in this invention only needs to control the longitudinal wave velocity of the piezoelectric layer of the TX filter and the RX filter along the thickness direction, so that the longitudinal wave velocity of the piezoelectric layer of the TX filter along the thickness direction is lower than that of the piezoelectric layer of the RX filter. This ensures the power capacity of the TX filter while minimizing the size and reducing the cost.

[0065] In one optional embodiment, the doping elements of the piezoelectric layer of the transmitting filter and the piezoelectric layer of the receiving filter are rare earth elements, including one or more of scandium, yttrium, magnesium, titanium, lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, and lutetium.

[0066] In this embodiment, the piezoelectric layer can be a single-crystal piezoelectric material, such as single-crystal aluminum nitride, single-crystal gallium nitride, single-crystal lithium niobate, single-crystal lead zirconate titanate (PZT), single-crystal potassium niobate, single-crystal quartz film, or single-crystal lithium tantalate, etc. It can also be a polycrystalline piezoelectric material (as opposed to single-crystal, a non-single-crystal material), such as polycrystalline aluminum nitride, zinc oxide, PZT, etc. The piezoelectric layer can also be a doped single-crystal piezoelectric material, such as doped aluminum nitride. The doping elements in the piezoelectric layer are rare earth elements, such as one or more of the following: scandium (Sc), yttrium (Y), magnesium (Mg), titanium (Ti), lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), and lutetium (Lu). For example, Sc can be doped into aluminum nitride.

[0067] In one optional embodiment, the piezoelectric layer of the transmitting filter and the piezoelectric layer of the receiving filter have the same doped elements but different doping concentrations, or...

[0068] The piezoelectric layer of the transmitting filter and the piezoelectric layer of the receiving filter have different doping elements.

[0069] Understandably, during the doping process of the piezoelectric layer, one approach is to select the same element to be doped in the piezoelectric layers of the TX and RX filters, but with different doping concentrations, so that the longitudinal wave velocity along the thickness direction of the piezoelectric layer of the TX filter is less than that of the piezoelectric layer of the RX filter. Another approach is to select different elements to be doped in the piezoelectric layers of the TX and RX filters. In this case, for example, when the doping concentration is the same, the longitudinal wave velocity along the thickness direction of the piezoelectric layer of the TX filter can also be less than that of the piezoelectric layer of the RX filter.

[0070] In one optional embodiment, the atomic fraction of the doping elements in the piezoelectric layer of the transmitting filter and the piezoelectric layer of the receiving filter ranges from 0% to 40%.

[0071] The atomic fraction of the doped elements in the piezoelectric layer of the transmitting filter is lower than the atomic fraction of the doped elements in the piezoelectric layer of the receiving filter.

[0072] In one optional embodiment, the atomic fraction of the doped elements in the piezoelectric layer of the transmitting filter and the piezoelectric layer of the receiving filter ranges from 8% to 30%.

[0073] In this embodiment, for example, the doped elements of the piezoelectric layer of the TX filter and the piezoelectric layer of the RX filter are the same. This allows the atomic fraction of the doped elements in the piezoelectric layer of the TX filter to be lower than that in the piezoelectric layer of the RX filter, resulting in a lower doping concentration for the TX filter compared to the RX filter. In other words, the longitudinal wave velocity along the thickness direction of the piezoelectric layer of the TX filter is lower than that of the piezoelectric layer of the RX filter. The atomic fraction (or atomic ratio) of the doped elements ranges from 0-40%. The atomic fraction can be 1%, 2%, 3%, 4%, 5%, 6%, 8%, 10%, 12%, 15%, 20%, 25%, 30%, 35%, 40%, etc. This invention does not specifically limit the value of the atomic fraction. Within this range, as the atomic fraction increases, the filter area decreases, but when the atomic fraction exceeds a certain proportion, the trend of area reduction tends to level off. Preferably, controlling the atomic fraction within the range of 8-30% allows the filter area to be reduced to a reasonable size.

[0074] In one optional implementation, the transmitting filter includes a plurality of first resonators, and the receiving filter includes a plurality of second resonators.

[0075] The first resonator and the second resonator each include a piezoelectric layer, and the doping concentration of the piezoelectric layer of the first resonator is the same as that of the piezoelectric layer of the second resonator.

[0076] It should be noted that TX and RX filters can be formed by multiple resonators connected in series, multiple resonators connected in parallel, or multiple resonators connected in both series and parallel. As mentioned earlier, the filter is a multi-layered structure. The resonator can include multiple layers such as a substrate, an acoustic mirror cavity and a bottom electrode, a piezoelectric layer, and a top electrode, but is not limited to these layers. It can also have one or more of the following layers: a temperature compensation layer, a mass loading layer, a protective layer (passivation layer), and a sacrificial layer. Doping the piezoelectric layer of the resonator can effectively reduce the area of ​​the resonator, thereby reducing the area of ​​the filter.

[0077] It is understandable that the thickness of the film layer corresponding to each TX resonator (first resonator) in the TX filter is the same, and the thickness of the film layer corresponding to each RX resonator (second resonator) in the RX filter is the same. Both the TX and RX resonators can include a piezoelectric layer, in which case the TX and RX filters in the duplexer each include a piezoelectric layer. It should be noted that in both the TX and RX filters, all resonators can be doped, or some resonators can be doped and some can be undoped; here, the doped resonators are those with piezoelectric layer doping. It is also understandable that regardless of the specific number of doped resonators used in the TX and RX filters, the longitudinal wave velocity along the thickness direction of the piezoelectric layer in the TX filter must be less than the longitudinal wave velocity along the thickness direction of the piezoelectric layer in the RX filter.

[0078] When both the piezoelectric layers of the TX and RX filters are doped with the same element, achieving a lower doping concentration in the piezoelectric layer of the TX filter compared to the RX filter allows for a lower doping concentration in the piezoelectric layers of the resonators within the TX filter compared to the resonators within the RX filter. For example, the piezoelectric layers of the resonators in the TX filter are all doped with a first concentration of impurity element, while the piezoelectric layers of the resonators in the RX filter are all doped with a second concentration of impurity element, where the first concentration is less than the second concentration.

[0079] When the doping concentration of the piezoelectric layer in the TX filter is lower than that in the RX filter, the doping concentration of the piezoelectric layer in the partially doped filter of the TX filter can also be the same as that of the piezoelectric layer in the resonator of the RX filter, while the doping concentration of the piezoelectric layer in the partially doped filter of the TX filter is lower than that of the piezoelectric layer in the resonator of the RX filter. For example, the piezoelectric layer in the partially doped filter of the TX filter is doped with an impurity element of a first concentration, and the piezoelectric layer in the partially doped filter of the TX filter is doped with an impurity element of a second concentration. The piezoelectric layers in the resonators of the RX filter are all doped with the second concentration of impurity element. Here, the first concentration is less than the second concentration, and the first concentration can be 0.

[0080] For example, such as Figure 7 As shown, the duplexer includes a TX filter and an RX filter fabricated on the same substrate. The TX filter includes multiple TX resonators, each comprising an acoustic mirror cavity, a bottom electrode BM_TX, a piezoelectric layer PZ_TX, and a top electrode TM_TX. The RX filter includes multiple RX resonators, each comprising an acoustic mirror cavity, a bottom electrode BM_RX, a piezoelectric layer PZ_RX, and a top electrode TM_RX. All resonators are doped with the same element. The doping concentration of the piezoelectric layer PZ_RX in all RX resonators is a second concentration. The doping concentration of the piezoelectric layer PZ_TX in some TX resonators is a second concentration, while the doping concentration of the piezoelectric layer PZ_TX in some TX resonators is a first concentration, where the first concentration is less than the second concentration.

[0081] In one optional implementation, the transmitting filter includes a plurality of first resonators, and the receiving filter includes a plurality of second resonators.

[0082] The first resonator and the second resonator each include multiple piezoelectric layers. The piezoelectric layers of the first resonator have the same doping elements but different doping concentrations, and the piezoelectric layers of the second resonator have the same doping elements but different doping concentrations.

[0083] In one optional implementation, for a multilayer piezoelectric layer, the thicknesses of each piezoelectric layer are t1, t2, ..., tn, and the doping concentrations of each piezoelectric layer are c1, c2, ..., cn, respectively. The total doping concentration of the piezoelectric layer is: (t1*c1+t2*c2+...+tn*cn) / (t1+t2+...+tn), where n is an integer greater than or equal to 2.

[0084] For a multilayer piezoelectric resonator, each piezoelectric layer of the first resonator in the TX filter can be doped with the same element, but the doping concentration of each piezoelectric layer can be different. Similarly, for each piezoelectric layer of the second resonator in the RX filter, each piezoelectric layer can be doped with the same element, but the doping concentration of each piezoelectric layer can be different. Here, the first and second resonators are doped with the same element, but regardless of the doping concentration of each piezoelectric layer in the first and second resonators, the total doping concentration of the piezoelectric layers in the first resonator must be less than the total doping concentration of the piezoelectric layers in the second resonator. That is, the total equivalent longitudinal wave velocity of the piezoelectric layers in the TX filter along the thickness direction must be less than the total equivalent longitudinal wave velocity of the piezoelectric layers in the RX filter along the thickness direction. The total doping concentration of the piezoelectric layers in both the first and second resonators can be calculated using the above formula.

[0085] In one optional implementation, the transmitting filter includes a plurality of first resonators, and the receiving filter includes a plurality of second resonators.

[0086] The first resonator and the second resonator each include multiple piezoelectric layers. The doping elements of each piezoelectric layer of the first resonator are different, and the doping elements of each piezoelectric layer of the second resonator are different. The total equivalent longitudinal wave velocity of the piezoelectric layer of the first resonator is less than that of the piezoelectric layer of the second resonator.

[0087] In one optional implementation, for a multilayer piezoelectric layer, the thicknesses of each piezoelectric layer are t1, t2, ..., tn, and the longitudinal wave sound velocities of each piezoelectric layer are v1, v2, ..., vn, respectively. The total equivalent longitudinal wave sound velocity of the piezoelectric layer is: (t1*v1+t2*v2+...+tn*vn) / (t1+t2+...+tn), where n is an integer greater than or equal to 2.

[0088] For a multilayer piezoelectric resonator, different elements can be doped into each piezoelectric layer of each first resonator in the TX filter. Similarly, different elements can be doped into each piezoelectric layer of each second resonator in the RX filter. In this case, regardless of the doping concentration of each piezoelectric layer in the first and second resonators, the total equivalent longitudinal wave velocity along the thickness direction of the piezoelectric layer in the first resonator must be less than that in the second resonator. Both the total equivalent longitudinal wave velocity along the thickness direction of the piezoelectric layers in the first and second resonators can be calculated using the above formula.

[0089] In one alternative implementation, the number of piezoelectric layers in the first resonator is different from the number of piezoelectric layers in the resonator.

[0090] It is understandable that the TX resonator and RX resonator can each include multiple piezoelectric layers. In this case, the TX filter and RX filter in the duplexer each include multiple piezoelectric layers. In the duplexer, the number of piezoelectric layers in the TX resonator (TX filter) and RX resonator (RX filter) can be the same or different, and the thickness of each piezoelectric layer can be the same or different. For example, the TX resonator may have more piezoelectric layers than the RX resonator. It is also understandable that regardless of the specific number of piezoelectric layers used in the TX and RX resonators, the total equivalent longitudinal wave velocity along the thickness direction of the piezoelectric layers in the TX filter must be lower than that in the RX filter. In this case, both the TX and RX filters can have all resonators as doped resonators, or some resonators as doped resonators and some as undoped resonators.

[0091] It should be noted that in a duplexer, for the TX filter's multilayer piezoelectric layers, each piezoelectric layer can have the same or different doping concentrations. Similarly, for the RX filter's multilayer piezoelectric layers, each piezoelectric layer can have the same or different doping concentrations. Furthermore, the doping concentration of the multilayer piezoelectric layers can vary periodically, alternately, or be symmetrically distributed. Of course, in a multilayer piezoelectric layer, each piezoelectric layer can also have a different doping concentration.

[0092] For example, such as Figure 8 As shown, the duplexer includes a TX filter and an RX filter fabricated on the same substrate. The TX filter includes multiple TX resonators, each comprising an acoustic mirror cavity, a bottom electrode BM_TX, a second piezoelectric layer PZ_TX2, a first piezoelectric layer PZ_TX1, and a top electrode TM_TX. The RX filter includes multiple RX resonators, each comprising an acoustic mirror cavity, a bottom electrode BM_RX, a piezoelectric layer PZ_RX, and a top electrode TM_RX. All resonators are doped with the same element. The doping concentration of the piezoelectric layer PZ_RX in the RX resonator is a second concentration, the doping concentration of the second piezoelectric layer PZ_TX2 in the TX resonator is a second concentration, and the doping concentration of the first piezoelectric layer PZ_TX1 in the TX resonator is a first concentration, where the first concentration is less than the second concentration.

[0093] In one alternative implementation, the thickness of at least one film layer in the first resonator is different from the thickness of the corresponding film layer in the second resonator.

[0094] It should be noted that, for filters with one or more piezoelectric layers, the thickness of the corresponding film layers in the TX and RX filters can be the same or different. For example, Figure 7 In this context, BM_TX and BM_RX have different thicknesses, and / or TM_TX and TM_RX have different thicknesses, and / or PZ_TX and PZ_RX have different thicknesses. For example, Figure 8 In this design, BM_TX and BM_RX have different thicknesses, and / or TM_TX and TM_RX have different thicknesses, and / or PZ_TX2 and PZ_RX have different thicknesses. Different film thicknesses allow for different frequencies. Furthermore, the doping of the piezoelectric layer alters the electromechanical coupling coefficient, thus enabling the fabrication of two filters with different frequencies and / or electromechanical coupling coefficients on the same substrate.

[0095] Figure 6-8 The diagram only schematically illustrates the stacking of individual resonators in two filters, omitting transitions or connections such as piezoelectric layers, top electrodes, and bottom electrodes between resonators (or between filters). That is, the area outside the resonators may or may not have a piezoelectric layer covering it, or it may have a continuously extending piezoelectric layer.

[0096] Figure 3 This invention integrates surface acoustic wave (SAW) devices onto a single substrate to form a duplexer. A wide range of filter frequencies can be adjusted by modifying the planar pattern and angular parameters of the interdigitated electrodes. The duplexer described in this invention uses bulk acoustic wave (BAW) resonators, which offer superior performance compared to SAW devices, for both the TX and RX filters. Integrating the TX and RX filters onto the same substrate and adjusting the electromechanical coupling coefficient and loss characteristics through piezoelectric layer doping allows the duplexer to maintain good performance while reducing chip size and cost. Furthermore, the frequency of the filter can be adjusted by modifying the film thickness of the BAW resonator, for example, using a masking method.

[0097] In one alternative implementation, the pad areas of the transmitting filter and / or the receiving filter are increased by at least one metal area.

[0098] In the operation of a communication system, to prevent interference from the transmitting signal to the receiving system and to avoid degrading the receiving sensitivity, the duplexer needs to have good isolation. For example... Figure 9 As shown, the solid line represents the existing duplexer ( Figure 1 and Figure 2The diagram shows the isolation of a duplexer (without forming TX and RX filters on the same substrate). The dashed line represents the isolation of the duplexer of this invention (with TX and RX filters formed on the same substrate) without increased metal region. It can be seen that the isolation of the duplexer of this invention is significantly degraded. This is because when the TX and RX filters are formed on the same substrate, on the one hand, the signal leakage between the substrates increases due to the shared substrate, leading to a deterioration in isolation; on the other hand, the closer proximity of the TX and RX filters results in greater coupling, which also degrades the isolation. Figure 10 As shown, the solid line represents the existing duplexer ( Figure 1 and Figure 2 The diagram shows the isolation of a duplexer (without TX and RX filters formed on the same substrate). The dashed line represents the isolation of the duplexer of this invention (with TX and RX filters formed on the same substrate) after adding a metal region. Figure 9 In comparison, it can be seen that the isolation is significantly improved after adding the metal region, and is basically close to the isolation of a duplexer that does not form TX and RX filters on the same substrate.

[0099] This invention improves the isolation of the duplexer by adding metal regions to the pad areas of the TX filter and / or RX filter. It should be noted that metal regions can be added to the pad areas corresponding to the TX filter, the RX filter, or both simultaneously. The pad areas can be on the substrate and / or base plate, for example, adding metal regions to pad areas on the substrate, adding metal regions to pad areas on the base plate, or adding metal regions to pad areas on both the substrate and base plate.

[0100] When adding metal regions to the pad areas corresponding to the TX and RX filters, one metal region can be added, or multiple metal regions can be added simultaneously. This invention does not impose a specific limit on the number of metal regions. For example... Figure 11As shown, metal regions 1, 2, 3, and 4 are added to the pad area corresponding to the TX filter. Metal region 1 is located between the TX filter input terminal TX_IN and the TX filter ground terminal TX_G2; metal region 2 is located between the TX filter ground terminal TX_G2 and the TX filter output terminal TX_OUT; metal region 3 is located between the TX filter output terminal TX_OUT and the TX filter ground terminal TX_G1; and metal region 4 is located between the TX filter ground terminal TX_G1 and the TX filter input terminal TX_IN. It should be noted that one or more of metal regions 1-4 can be added. For example, metal region 1 can be added, metal regions 1 and 3 can be added simultaneously, metal regions 2 and 3 can be added simultaneously, and metal regions 1, 3, and 4 can be added simultaneously, etc. Similarly, one or more of metal regions 1-4 can also be added to the RX filter. The metal regions added to the RX filter are not shown in the figure.

[0101] In one alternative implementation, the metal regions of the transmitting filter and the receiving filter extend toward their respective pin directions.

[0102] It should be noted that the shape of the metal region is not specifically limited when adding it in this invention. The metal regions added to the TX and RX filters can extend towards their pin directions to reduce coupling and achieve better isolation. It should also be noted that the pin directions of the TX and RX filters can be their input direction, output direction, or ground direction. The metal region added to the TX filter can be oriented towards its input direction and / or output direction and / or ground direction. Correspondingly, the metal region added to the RX filter can be oriented towards its input direction and / or output direction and / or ground direction. For example, ... Figure 12 As shown, metal regions 1, 2, 3, 4, 5, and 6 are added to the pad area corresponding to the TX filter. Metal region 1 is located between the TX filter input terminal TX_IN and the TX filter ground terminal TX_G2; metal region 2 is located between the TX filter ground terminal TX_G2 and the TX filter output terminal TX_OUT; metal region 3 is located between the TX filter output terminal TX_OUT and the TX filter ground terminal TX_G1; metal region 4 is located between the TX filter ground terminal TX_G1 and the TX filter input terminal TX_IN; metal region 5 is located between the RX filter ground terminal RX_G2 and the TX filter ground terminal TX_G2; and metal region 6 is located between the RX filter input terminal RX_IN and the RX filter ground terminal RX_G2. Metal regions 1 and 6 are connected as one unit and extend to the TX filter ground terminal TX_G2; metal regions 2 and 5 both extend to the TX filter ground terminal TX_G2; and metal regions 3 and 4 both extend to the TX filter ground terminal TX_G1.

[0103] The present invention discloses a method for manufacturing a duplexer, wherein the duplexer includes a transmitting filter and a receiving filter, the transmitting filter and the receiving filter comprising a stacked structure formed of multiple film layers, and the method includes:

[0104] The transmitting filter and the receiving filter are formed on the same substrate, and elements are doped in the piezoelectric layer of the transmitting filter and the piezoelectric layer of the receiving filter so that the longitudinal wave velocity of the piezoelectric layer of the transmitting filter along the thickness direction is less than the longitudinal wave velocity of the piezoelectric layer of the receiving filter along the thickness direction.

[0105] The TX and RX filters of the duplexer described in this invention are integrated by fabricating on the same substrate, allowing the duplexer chip to be fabricated in a single process, followed by a single packaging process on the substrate. This reduces the number of packaging steps, and since the TX and RX filters can share some structural components, the overall chip size can be reduced, lowering costs. Furthermore, since the spacing between the TX and RX filters can be eliminated during the packaging process, the chip size can be further reduced.

[0106] The duplexer described in this invention only needs to control the longitudinal wave velocity of the piezoelectric layer of the TX filter and the RX filter along the thickness direction, so that the longitudinal wave velocity of the piezoelectric layer of the TX filter along the thickness direction is lower than that of the piezoelectric layer of the RX filter. This ensures the power capacity of the TX filter while minimizing the size and reducing the cost.

[0107] In one optional embodiment, the step of doping the piezoelectric layers of the transmitting filter and the receiving filter with elements such that the longitudinal wave velocity along the thickness direction of the piezoelectric layer of the transmitting filter is less than the longitudinal wave velocity along the thickness direction of the piezoelectric layer of the receiving filter includes:

[0108] The piezoelectric layers of the transmitting filter and the receiving filter are doped with the same element but at different concentrations, or...

[0109] Different elements are doped into the piezoelectric layer of the transmitting filter and the piezoelectric layer of the receiving filter.

[0110] In the doping process of the piezoelectric layer, one option is to select the same element to be doped in the piezoelectric layers of the TX filter and the RX filter, but with different doping concentrations, so that the longitudinal wave velocity of the piezoelectric layer of the TX filter along the thickness direction is less than that of the piezoelectric layer of the RX filter. Another option is to select different elements to be doped in the piezoelectric layers of the TX filter and the RX filter. In this case, for example, when the doping concentration is the same, the longitudinal wave velocity of the piezoelectric layer of the TX filter along the thickness direction can also be made less than that of the piezoelectric layer of the RX filter.

[0111] The doping elements in the piezoelectric layer are rare earth elements, such as one or more of the following: scandium (Sc), yttrium (Y), magnesium (Mg), titanium (Ti), lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), and lutetium (Lu). The piezoelectric layers of the TX filter and the RX filter can use the same doping elements or different doping elements.

[0112] For example, the doped elements in the piezoelectric layer of the TX filter are the same as those in the piezoelectric layer of the RX filter. However, the atomic fraction of the doped elements in the piezoelectric layer of the TX filter is lower than that in the piezoelectric layer of the RX filter, so that the doping concentration of the TX filter is lower than that of the RX filter. This means that the longitudinal wave velocity along the thickness direction of the piezoelectric layer of the TX filter is lower than that of the piezoelectric layer of the RX filter. The atomic fraction (or atomic ratio) of the doped elements ranges from 0-40%. The atomic fraction can be 1%, 2%, 3%, 4%, 5%, 6%, 8%, 10%, 12%, 15%, 20%, 25%, 30%, 35%, 40%, etc. This invention does not specifically limit the value of the atomic fraction. Within this range, as the atomic fraction increases, the filter area decreases, but when the atomic fraction exceeds a certain proportion, the trend of area reduction tends to level off. Preferably, controlling the atomic fraction within the range of 8-30% can reduce the filter area to a reasonable size.

[0113] In one optional implementation, the transmitting filter includes a plurality of first resonators, and the receiving filter includes a plurality of second resonators, wherein the first resonators and the second resonators each include a piezoelectric layer, and the method further includes:

[0114] Doping elements are performed on the piezoelectric layers of the first resonator and the second resonator, such that the doping concentration of a portion of the piezoelectric layer of the first resonator is the same as that of the piezoelectric layer of the second resonator.

[0115] This invention, when achieving a lower doping concentration of the piezoelectric layer in the TX filter than in the RX filter, can ensure that the doping concentration of the piezoelectric layer in all doped resonators of the TX filter is lower than that of the piezoelectric layer in the doped resonators of the RX filter. Alternatively, it can ensure that the doping concentration of the piezoelectric layer in some doped filters of the TX filter is the same as that of the piezoelectric layer in the doped resonators of the RX filter, while the doping concentration of the piezoelectric layer in some doped filters of the TX filter is lower than that of the piezoelectric layer in the doped resonators of the RX filter.

[0116] In one optional implementation, the transmitting filter includes a plurality of first resonators, and the receiving filter includes a plurality of second resonators, wherein the first resonators and the second resonators each include multiple piezoelectric layers, and the method further includes:

[0117] The first resonator has piezoelectric layers doped with the same element but with different doping concentrations, and the second resonator has piezoelectric layers doped with the same element but with different doping concentrations, so that the total doping concentration of the piezoelectric layers in the first resonator is less than that in the second resonator.

[0118] In one optional implementation, the transmitting filter includes a plurality of first resonators, and the receiving filter includes a plurality of second resonators, wherein the first resonators and the second resonators each include multiple piezoelectric layers, and the method further includes:

[0119] Different elements are doped into each piezoelectric layer of the first resonator and into each piezoelectric layer of the second resonator, so that the total equivalent longitudinal wave velocity of the piezoelectric layer of the first resonator is less than that of the piezoelectric layer of the second resonator.

[0120] The total doping concentration and the total equivalent longitudinal wave velocity of the piezoelectric layer are as described above and will not be repeated here.

[0121] The number of piezoelectric layers in the TX resonator (TX filter) and RX resonator (RX filter) of this invention can be the same or different, and the thickness of each piezoelectric layer in the resonator can be the same or different. In the multilayer piezoelectric layer, each piezoelectric layer can use the same doping concentration or different doping concentrations.

[0122] In one optional implementation, the method further includes:

[0123] By processing the film layers of the first resonator and / or the second resonator, the thickness of at least one film layer in the first resonator is different from the thickness of the corresponding film layer in the second resonator.

[0124] In this invention, for filters with one or more piezoelectric layers, the thickness of the corresponding film layers in the TX and RX filters can be the same or different. Different film thicknesses can achieve different frequencies. In addition, the doping of the piezoelectric layer changes the electromechanical coupling coefficient. Therefore, two filters with different frequencies and / or electromechanical coupling coefficients can be fabricated on the same substrate.

[0125] In an optional implementation, the method further includes:

[0126] At least one metal region is added to the pad area of ​​the transmitting filter and / or the receiving filter.

[0127] This invention can add a metal region to the pad area corresponding to the TX filter, thereby improving the isolation of the duplexer. A metal region can also be added to the pad area corresponding to the RX filter, or simultaneously to the pad areas corresponding to both the TX and RX filters. The pad area can be a pad area on the substrate and / or a base plate.

[0128] In one alternative implementation, the at least one metal region extends toward the pin direction.

[0129] When adding metal regions, the present invention does not specifically limit the shape of the metal regions. The metal regions added to the TX and RX filters can be extended toward their ground ends to reduce coupling and achieve better isolation.

[0130] This invention also relates to an electronic device, including the aforementioned duplexer. It should be noted that the electronic device referred to herein includes, but is not limited to, intermediate products such as filter amplification modules and radio frequency front-ends, as well as terminal products such as mobile phones, Wi-Fi modules, and drones.

[0131] Numerous specific details are set forth in the specification provided herein. However, it will be understood that embodiments of the invention may be practiced without these specific details. In some instances, well-known methods, structures, and techniques have not been shown in detail so as not to obscure the understanding of this specification.

[0132] Furthermore, those skilled in the art will understand that although some embodiments described herein include certain features but not others included in other embodiments, combinations of features from different embodiments are intended to be within the scope of the invention and form different embodiments. For example, in the claims, any of the claimed embodiments can be used in any combination.

[0133] Those skilled in the art will understand that although the invention has been described with reference to exemplary embodiments, various changes may be made and its elements may be substituted with equivalents without departing from the scope of the invention. Furthermore, many modifications may be made to adapt particular situations or materials to the teachings of the invention without departing from the essential scope of the invention. Therefore, the invention is not limited to the specific embodiments disclosed, but rather the invention will include all embodiments falling within the scope of the appended claims.

Claims

1. A duplexer, characterized in that, The duplexer includes: A transmitting filter and a receiving filter formed on the same substrate, the transmitting filter and the receiving filter comprising a stacked structure formed of multiple film layers, wherein the piezoelectric layer of the transmitting filter and the piezoelectric layer of the receiving filter are doped with elements, and the longitudinal wave velocity of the piezoelectric layer of the transmitting filter along the thickness direction is less than the longitudinal wave velocity of the piezoelectric layer of the receiving filter along the thickness direction. Wherein, the piezoelectric layer of the transmitting filter and the piezoelectric layer of the receiving filter have the same doping elements but different doping concentrations, or the piezoelectric layer of the transmitting filter and the piezoelectric layer of the receiving filter have different doping elements; The transmitting filter includes multiple first resonators, and the receiving filter includes multiple second resonators. The first resonators and the second resonators each include multiple piezoelectric layers. The piezoelectric layers of the first resonator have the same doping element but different doping concentrations, and the piezoelectric layers of the second resonator have the same doping element but different doping concentrations. The total doping concentration of the piezoelectric layers of the first resonator is less than the total doping concentration of the piezoelectric layers of the second resonator. Alternatively, the transmitting filter may include multiple first resonators, and the receiving filter may include multiple second resonators. The first resonator and the second resonator may each include multiple piezoelectric layers. The doping elements of each piezoelectric layer of the first resonator are different, and the doping elements of each piezoelectric layer of the second resonator are different. The total equivalent longitudinal wave velocity of the piezoelectric layer of the first resonator is less than the total equivalent longitudinal wave velocity of the piezoelectric layer of the second resonator.

2. The duplexer as claimed in claim 1, wherein, The atomic fraction of the doped elements in the piezoelectric layer of the transmitting filter and the piezoelectric layer of the receiving filter ranges from 0% to 40%, wherein the atomic fraction of the doped elements in the piezoelectric layer of the transmitting filter is lower than the atomic fraction of the doped elements in the piezoelectric layer of the receiving filter.

3. The duplexer as described in claim 2, wherein, The atomic fraction of the doped elements in the piezoelectric layer of the transmitting filter and the piezoelectric layer of the receiving filter ranges from 8% to 30%.

4. The duplexer as claimed in claim 1, wherein, The transmitting filter includes a plurality of first resonators, and the receiving filter includes a plurality of second resonators. Each of the first and second resonators includes a piezoelectric layer, and the doping concentration of the piezoelectric layer of a portion of the first resonator is the same as the doping concentration of the piezoelectric layer of the second resonator.

5. The duplexer as claimed in claim 1, wherein, For a multilayer piezoelectric layer, the thicknesses of each piezoelectric layer are t1, t2, ..., tn, and the doping concentrations of each piezoelectric layer are c1, c2, ..., cn, respectively. The total doping concentration of the piezoelectric layer is: (t1 c1+t2 c2+…+tn cn) / (t1+t2+…+tn), where n is an integer greater than or equal to 2.

6. The duplexer as claimed in claim 1, wherein, The number of piezoelectric layers in the first resonator is different from the number of piezoelectric layers in the second resonator.

7. The duplexer as claimed in claim 1, wherein, The thickness of at least one film layer in the first resonator is different from the thickness of the corresponding film layer in the second resonator.

8. The duplexer as claimed in claim 1, wherein, The pad areas of the transmitting filter and / or the receiving filter are increased by at least one metal area.

9. The duplexer as claimed in claim 8, wherein, The metal regions of the transmitting filter and the receiving filter extend toward their respective pins.

10. The duplexer as claimed in claim 1, wherein, The piezoelectric layer of the transmitting filter and the piezoelectric layer of the receiving filter are made of aluminum nitride or doped aluminum nitride, wherein the doping element of the doped aluminum nitride is scandium.

11. A method for manufacturing a duplexer, used to manufacture the duplexer as described in claim 1, characterized in that, The duplexer includes a transmitting filter and a receiving filter, the transmitting filter and the receiving filter comprising a stacked structure formed of multiple film layers, the method comprising: forming the transmitting filter and the receiving filter on the same substrate, and doping elements in the piezoelectric layer of the transmitting filter and the piezoelectric layer of the receiving filter such that the longitudinal wave velocity of the piezoelectric layer of the transmitting filter along the thickness direction is less than the longitudinal wave velocity of the piezoelectric layer of the receiving filter along the thickness direction.

12. The method of claim 11, wherein, The step of doping elements in the piezoelectric layers of the transmitting filter and the receiving filter such that the longitudinal wave velocity along the thickness direction of the piezoelectric layer of the transmitting filter is less than that of the piezoelectric layer of the receiving filter includes: doping the piezoelectric layers of the transmitting filter and the receiving filter with the same element but different doping concentrations, or doping the piezoelectric layers of the transmitting filter and the receiving filter with different elements.

13. The method of claim 11, wherein, The transmitting filter includes a plurality of first resonators, and the receiving filter includes a plurality of second resonators. The first resonator and the second resonator each include a piezoelectric layer. The method further includes: doping elements in the piezoelectric layers of the first resonator and the second resonator, such that the doping concentration of the piezoelectric layer of a portion of the first resonator is the same as the doping concentration of the piezoelectric layer of the second resonator.

14. The method of claim 11, wherein, The transmitting filter includes multiple first resonators, and the receiving filter includes multiple second resonators. The first resonators and the second resonators each include multiple piezoelectric layers. The method further includes: doping each piezoelectric layer of the first resonator with the same element and different doping concentrations in each piezoelectric layer; and doping each piezoelectric layer of the second resonator with the same element and different doping concentrations in each piezoelectric layer, so that the total doping concentration of the piezoelectric layers of the first resonator is less than the total doping concentration of the piezoelectric layers of the second resonator.

15. The method of claim 11, wherein, The transmitting filter includes multiple first resonators, and the receiving filter includes multiple second resonators. The first resonators and the second resonators each include multiple piezoelectric layers. The method further includes: doping each piezoelectric layer of the first resonator with different elements, and doping each piezoelectric layer of the second resonator with different elements, so that the total equivalent longitudinal wave velocity of the piezoelectric layer of the first resonator is less than the total equivalent longitudinal wave velocity of the piezoelectric layer of the second resonator.

16. The method according to any one of claims 13-15, wherein, The method further includes: processing the film layers of the first resonator and / or the second resonator so that the thickness of at least one film layer in the first resonator is different from the thickness of the corresponding film layer in the second resonator.

17. The method of claim 11, wherein, The method further includes: At least one metal region is added to the pad area of ​​the transmitting filter and / or the receiving filter.

18. The method of claim 17, wherein, The at least one metal region extends toward the pin direction.

19. An electronic device comprising a duplexer as described in any one of claims 1-10.

Images