Elastic wave device, circuit and electronic apparatus

Abstract

Provided in the present application are an elastic wave device, a circuit and an electronic apparatus. The elastic wave device comprises an electrode and two piezoelectric layers, wherein the two piezoelectric layers may be respectively referred to as a first piezoelectric layer and a second piezoelectric layer; the electrode is provided on the first piezoelectric layer, and the first piezoelectric layer is provided on the second piezoelectric layer; and the electrode is configured to generate an elastic wave having a wavelength λ. The Euler angle of the first piezoelectric layer is different from that of the second piezoelectric layer; and the material of the first piezoelectric layer is the same as that of the second piezoelectric layer, and the first piezoelectric layer and the second piezoelectric layer are made of lithium tantalate or lithium niobate. The two piezoelectric layers having different Euler angles can suppress or reduce unnecessary high-order modal responses, such that the primary vibration mode of the elastic wave device has good electrical characteristics.

Description

Elastic wave devices, circuits, and electronic devices

[0001] This application claims priority to the Chinese patent application filed with the State Intellectual Property Office of China on February 22, 2024, with application number 202410201561.1, and priority to the Chinese patent application entitled “Elastic Wave Devices, Circuits and Electronic Devices”, all contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the field of electronic technology, and more specifically, to elastic wave devices, circuits and electronic devices. Background Art

[0003] Elastic wave devices are widely used in devices such as resonators and filters. For example, a surface acoustic wave (SAW) filter is a common elastic wave device. SAW filters are specialized filtering devices made from piezoelectric materials such as quartz crystals and piezoelectric ceramics, utilizing their piezoelectric effect and the physical properties of surface acoustic wave propagation. SAW is widely used in the field of mobile communications. For example, the filter in the radio frequency circuit of a mobile terminal can include a SAW filter. Summary of the Invention

[0004] The present application provides an elastic wave device, a circuit, and an electronic device. The elastic wave device provided in the embodiments of the present application has good electrical characteristics in its main vibration mode.

[0005] In a first aspect, an embodiment of the present application provides an elastic wave device. The elastic wave device includes an electrode and two piezoelectric layers. The two piezoelectric layers can be referred to as a first piezoelectric layer and a second piezoelectric layer, respectively. The electrode is disposed on the first piezoelectric layer, and the first piezoelectric layer is disposed above the first piezoelectric layer. The electrode is configured to generate an elastic wave having a wavelength λ. The Euler angle of the first piezoelectric layer is different from the Euler angle of the second piezoelectric layer. The material of the first piezoelectric layer is the same as the material of the second piezoelectric layer, and the material of the first piezoelectric layer and the second piezoelectric layer is lithium tantalate or lithium niobate.

[0006] The two piezoelectric layers with different Euler angles can suppress or reduce unnecessary high-order modal responses, thereby making the main vibration mode of the elastic wave device have good electrical characteristics.

[0007] In combination with the first aspect, in a possible implementation of the first aspect, a thickness of the first piezoelectric layer is less than a thickness of the second piezoelectric layer.

[0008] In combination with the first aspect, in a possible implementation of the first aspect, a ratio of the thickness of the first piezoelectric layer to the thickness of the second piezoelectric layer is 1:2.

[0009] In combination with the first aspect, in a possible implementation of the first aspect, a sum of a thickness of the first piezoelectric layer and a thickness of the second piezoelectric layer is less than or equal to 0.4λ.

[0010] In combination with the first aspect, in a possible implementation of the first aspect, the Euler angle of the first piezoelectric layer is The Euler angle of the second piezoelectric layer is

[0011] By adjusting the thickness and / or Euler angle of the first piezoelectric layer and the second piezoelectric layer, the electrical characteristics of the elastic wave device can be further improved.

[0012] In combination with the first aspect, in a possible implementation of the first aspect, a sign of a piezoelectric constant tensor of the first piezoelectric layer is different from a sign of a piezoelectric constant tensor of the second piezoelectric layer.

[0013] With reference to the first aspect, in a possible implementation of the first aspect, a thickness of the electrode is greater than or equal to 0.03λ and less than or equal to 0.12λ.

[0014] In combination with the first aspect, in a possible implementation of the first aspect, the elastic wave device also includes a supporting substrate located below the second piezoelectric layer, and the speed of the elastic wave of the supporting substrate is greater than the speed of the elastic wave of the first piezoelectric layer and the second piezoelectric layer.

[0015] The use of high-speed materials for the supporting substrate can further improve the electrical performance of the elastic wave device.

[0016] In combination with the first aspect, in a possible implementation of the first aspect, the elastic wave device also includes a temperature compensation layer, which is located between the second piezoelectric layer and the supporting substrate, and the sign of the temperature coefficient of the temperature compensation layer is opposite to the sign of the temperature coefficient of the first piezoelectric layer and the second piezoelectric layer.

[0017] The above technical solution introduces a temperature compensation layer to reduce the frequency deviation caused by temperature changes.

[0018] In combination with the first aspect, in a possible implementation of the first aspect, a speed of the elastic wave of the temperature compensation layer is smaller than a speed of the elastic wave of the first piezoelectric layer and the second piezoelectric layer.

[0019] The temperature compensation layer uses low-speed materials, which can further improve the electrical performance of the elastic wave device.

[0020] In combination with the first aspect, in a possible implementation manner of the first aspect, the elastic wave further includes an intermediate dielectric layer, and the intermediate dielectric layer is located between the temperature compensation layer and the supporting substrate.

[0021] In a second aspect, an embodiment of the present application provides a circuit comprising one or more elastic wave devices as described in the first aspect or any possible implementation of the first aspect.

[0022] In a third aspect, an embodiment of the present application provides an electronic device, which includes the circuit as described in the second aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] FIG1 shows a schematic structural diagram of an electronic device 100 .

[0024] FIG2 is a schematic structural diagram of an elastic wave device provided according to an embodiment of the present application.

[0025] FIG3 is a schematic diagram of a conventional elastic wave device.

[0026] FIG4 shows characteristic curves of an elastic wave device according to an embodiment of the present application and a traditional elastic wave device.

[0027] FIG5 is another elastic wave device provided according to an embodiment of the present application.

[0028] FIG6 is a schematic diagram of a conventional elastic wave device.

[0029] FIG. 7 shows characteristic curves of an elastic wave device according to an embodiment of the present application and a traditional elastic wave device.

[0030] FIG8 is another elastic wave device provided according to an embodiment of the present application.

[0031] FIG9 is a schematic diagram of a conventional elastic wave device.

[0032] FIG10 shows characteristic curves of the elastic wave device provided according to an embodiment of the present application and a traditional elastic wave device.

[0033] FIG11 is a schematic diagram of electrodes of a SAW filter.

[0034] FIG12 is a schematic diagram of an electrode finger period. DETAILED DESCRIPTION

[0035] The technical solutions of this application are described below with reference to the accompanying drawings. It should be understood that the drawings in the embodiments of this application are merely schematic diagrams intended to help those skilled in the art better understand the structure of the elastic wave device. The size and thickness ratios of the various components in the drawings do not necessarily reflect actual size ratios.

[0036] In the embodiments of this application, words such as "exemplary" and "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design described in this application as "exemplary" should not be construed as preferred or advantageous over other embodiments or designs. Rather, the use of the word "exemplary" is intended to present concepts in a concrete way.

[0037] In the embodiments of the present application, “corresponding” and “relevant” may sometimes be used interchangeably. It should be noted that when the distinction between them is not emphasized, the meanings they intend to express are consistent.

[0038] The network architecture and business scenarios described in the embodiments of the present application are intended to more clearly illustrate the technical solutions of the embodiments of the present application, and do not constitute a limitation on the technical solutions provided in the embodiments of the present application. A person skilled in the art will appreciate that, with the evolution of the network architecture and the emergence of new business scenarios, the technical solutions provided in the embodiments of the present application are equally applicable to similar technical problems.

[0039] References to "one embodiment" or "some embodiments" in this specification mean that a particular feature, structure, or characteristic described in conjunction with that embodiment is included in one or more embodiments of the present application. Thus, phrases such as "in one embodiment," "in some embodiments," "in other embodiments," and "in yet other embodiments" appearing in various places in this specification do not necessarily refer to the same embodiment, but rather mean "one or more but not all embodiments," unless otherwise specifically emphasized. The terms "including," "comprising," "having," and variations thereof mean "including but not limited to," unless otherwise specifically emphasized.

[0040] In this application, "at least one" means one or more, and "more" means two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can mean: including the existence of A alone, the existence of A and B at the same time, and the existence of B alone, where A and B can be singular or plural. The character " / " generally indicates that the previous and next associated objects are in an "or" relationship. "At least one of the following items" or similar expressions refers to any combination of these items, including any combination of single or plural items. For example, at least one of a, b, or c can mean: a, b, c, ab, ac, bc, or abc, where a, b, c can be single or multiple.

[0041] It should be understood that the following descriptions are merely examples and are not intended to be limiting. For example, in the following descriptions, disposing a second component above or on a first component may include embodiments in which the first component and the second component are directly in contact, embodiments in which the first component is attached to the first component via an adhesive, and embodiments in which additional components are disposed directly between the first component and the second component, thereby eliminating direct contact between the first component and the second component.

[0042] The elastic wave device in the embodiments of the present application may be a filter (eg, a SAW filter, a bulk acoustic wave (BAW) filter), a resonator (eg, a SAW resonator, a BAW resonator), a duplexer, etc.

[0043] 1 shows a schematic structural diagram of an electronic device 100. The electronic device 100 may include a processor 110, a memory 120, a communication module 130, and an antenna 131.

[0044] It should be understood that the structures illustrated in the embodiments of the present application do not constitute a specific limitation on the electronic device 100. In other embodiments of the present application, the electronic device 100 may include more or fewer components than shown, or may combine or separate certain components, or arrange the components differently. The illustrated components may be implemented in hardware, software, or a combination of software and hardware.

[0045] The processor 110 may include one or more processing units. For example, the processor 110 may include an application processor (AP), a modem processor, a graphics processing unit (GPU), an image signal processor (ISP), a controller, a memory, a video codec, a digital signal processor (DSP), a baseband processor, and / or a neural-network processing unit (NPU). The different processing units may be independent devices or integrated into one or more processors.

[0046] The memory 120 can be used to store computer executable program codes, which include instructions. The processor 110 executes various functional applications and data processing of the electronic device 100 by running the instructions stored in the memory 120. The memory 120 may include a program storage area and a data storage area. Among them, the program storage area may store an operating system, an application required for at least one function (such as a sound playback function, an image playback function, etc.), etc. The data storage area may store data created during the use of the electronic device 100 (such as audio data, video data, etc.), etc. In addition, the memory 120 may include a high-speed random access memory, and may also include a non-volatile memory, such as at least one disk storage device, a flash memory device, a universal flash storage (UFS), etc.

[0047] The communication module 130 can provide a wireless communication solution for the electronic device 100. The antenna 131 of the electronic device 100 is coupled to the communication module 130, so that the electronic device 100 can communicate with the network and other devices through wireless communication technology. The wireless communication technology may include global system for mobile communications (GSM), general packet radio service (GPRS), code division multiple access (CDMA), wideband code division multiple access (WCDMA), time-division code division multiple access (TD-SCDMA), long term evolution (LTE), fifth generation (5G) and so on. th generation, 5G) system or new radio (NR), the future sixth generation (6 thThese include non-terrestrial network (NTN) systems such as 6G (sixth generation) systems, intersatellite and satellite communications, wireless local area networks (WLANs) (such as wireless fidelity (Wi-Fi) networks), Bluetooth (BT), global navigation satellite systems (GNSS), frequency modulation (FM), near field communication (NFC), and infrared (IR). Satellite communication systems include satellite base stations and terminal devices. The satellite base station provides communication services to the terminal device. The satellite base station can also communicate with other base stations. A satellite can serve as both a base station and a terminal device. A satellite can refer to an unmanned aerial vehicle (UAV), a hot air balloon, a low-orbit satellite, a medium-orbit satellite, or a high-orbit satellite. A satellite can also refer to a non-terrestrial base station or non-terrestrial device. GNSS may include the global positioning system (GPS), the global navigation satellite system (GLONASS), the Beidou navigation satellite system (BDS), the quasi-zenith satellite system (QZSS) and / or the satellite based augmentation system (SBAS).

[0048] The communication module 130 may include at least one filter, a switch, a power amplifier, a low noise amplifier (LNA), etc. The communication module 130 may receive electromagnetic waves through the antenna 131, filter, amplify, and perform other processing on the received electromagnetic waves, and transmit them to the modem processor for demodulation. The communication module 130 may also amplify the signal modulated by the modem processor and convert it into electromagnetic waves for radiation through the antenna 131. In some embodiments, at least some of the functional modules of the communication module 130 may be set in the processor 110. In some embodiments, at least some of the functional modules of the communication module 130 may be set in the same device as at least some of the modules of the processor 110.

[0049] The elastic wave device provided in the embodiment of the present application can be applied to the communication module 130. For example, the communication module 130 can include a SAW filter or a BAW filter provided in the embodiment of the present application.

[0050] Exemplarily, the electronic device 100 may be a mobile phone, a tablet computer, a laptop computer, a PDA, a mobile internet device (MID), a wearable device, a virtual reality (VR) device, an augmented reality (AR) device, a wireless terminal in industrial control, a terminal in vehicle-to-everything (V2X), a wireless terminal in self-driving, a wireless terminal in remote medical surgery, a wireless terminal in smart grid, a wireless terminal in transportation safety, a wireless terminal in smart city, a wireless terminal in smart home, a cellular phone, a cordless phone, a session initiation protocol (SIP) phone, a wireless local loop (WLL) station, a personal digital assistant (PDA), or a similar device. assistant, PDA), a handheld device with wireless communication function, a computing device or other processing device connected to a wireless modem, a wearable device, a terminal device in a 5G network, or a terminal device in a future evolved public land mobile communication network (public land mobile network, PLMN), etc. The embodiment of the present application does not limit the specific form of the electronic device 100.

[0051] FIG2 is a schematic structural diagram of an elastic wave device according to an embodiment of the present application. As shown in FIG2 , the elastic wave device 200 includes an electrode 210 , a first piezoelectric layer 220 , and a second piezoelectric layer 230 .

[0052] As shown in FIG. 2 , the electrode 210 is disposed above the first piezoelectric layer 220 , and the first piezoelectric layer 220 is disposed above the second piezoelectric layer 230 .

[0053] The material of the electrode 210 can be an appropriate metal material such as aluminum (Al), copper (Cu), platinum (Pt), gold (Au), silver (Ag), titanium (Ti), nickel (Ni), chromium (Cr), molybdenum (Mo), or tungsten (W), or an alloy mainly composed of any of these metals. The electrode 210 may also have a structure formed by stacking multiple metal films composed of these metals or alloys.

[0054] The material of the first piezoelectric layer 220 and the second piezoelectric layer 230 can be lithium tantalate crystal or lithium niobate crystal. For example, in some embodiments, the material of the first piezoelectric layer 220 can be lithium tantalate single crystal. For another example, in other embodiments, the material of the first piezoelectric layer 220 can be lithium niobate single crystal. The material of the first piezoelectric layer 220 is the same as the material of the second piezoelectric layer 230. In other words, if the material of the first piezoelectric layer 220 is lithium niobate single crystal, then the material of the second piezoelectric layer 230 is also lithium niobate single crystal.

[0055] The Euler angle of the first piezoelectric layer 220 is different from the Euler angle of the second piezoelectric layer 230 .

[0056] The elastic wave device provided in the embodiments of the present application includes two piezoelectric layers with different Euler angles. These two piezoelectric layers with different Euler angles can suppress or reduce unnecessary high-order modal responses, thereby ensuring that the main vibration mode of the elastic wave device has good electrical characteristics.

[0057] A conventional elastic wave device comprises only one piezoelectric layer. For example, FIG3 is a schematic diagram of a conventional elastic wave device. The elastic wave device shown in FIG3 comprises only electrodes 310 and one piezoelectric layer 320.

[0058] Compared with the elastic wave device provided in the embodiments of the present application, traditional elastic wave devices usually generate unnecessary high-order modal responses.

[0059] Figure 4 shows characteristic curves of an elastic wave device according to an embodiment of the present application and a conventional elastic wave device. The solid line in Figure 4 is the characteristic curve of elastic wave device 200 , and the dashed line in Figure 4 is the characteristic curve of elastic wave device 300 .

[0060] Referring to FIG. 4 , at frequencies around 1400 MHz, 2000 MHz, and 2300 MHz, the high-order modal responses of elastic wave device 300 are significantly greater than those of elastic wave device 200. This demonstrates that the elastic wave device provided in accordance with embodiments of the present application can suppress high-order modal responses, thereby improving the electrical characteristics of the elastic wave device in its primary vibration mode.

[0061] FIG5 shows another elastic wave device according to an embodiment of the present application. As shown in FIG5 , the elastic wave device 500 includes an electrode 510 , a first piezoelectric layer 520 , a second piezoelectric layer 530 , and a support substrate 540 .

[0062] As shown in FIG. 5 , the electrode 510 is disposed above the first piezoelectric layer 520 , the first piezoelectric layer 520 is disposed above the second piezoelectric layer 530 , and the second piezoelectric layer 530 is disposed above the supporting substrate 540 .

[0063] The material of the electrode 510 can be an appropriate metal material such as aluminum (Al), copper (Cu), platinum (Pt), gold (Au), silver (Ag), titanium (Ti), nickel (Ni), chromium (Cr), molybdenum (Mo), or tungsten (W), or an alloy mainly composed of any of these metals. The electrode 510 may also have a structure formed by stacking multiple metal films composed of these metals or alloys.

[0064] The material of the first piezoelectric layer 520 and the second piezoelectric layer 530 can be lithium tantalate crystal or lithium niobate crystal. For example, in some embodiments, the material of the first piezoelectric layer 520 can be lithium tantalate single crystal. For another example, in other embodiments, the material of the first piezoelectric layer 520 can be lithium niobate single crystal. The material of the first piezoelectric layer 520 is the same as the material of the second piezoelectric layer 530. In other words, if the material of the first piezoelectric layer 520 is lithium niobate single crystal, then the material of the second piezoelectric layer 530 is also lithium niobate single crystal.

[0065] The Euler angle of the first piezoelectric layer 520 is different from the Euler angle of the second piezoelectric layer 530 .

[0066] The support substrate 540 may be made of silicon, aluminum nitride, quartz, sapphire, spinel, or the like.

[0067] FIG6 is a schematic diagram of a conventional elastic wave device. The elastic wave device shown in FIG6 only includes an electrode 610 , a piezoelectric layer 620 , and a supporting substrate 630 .

[0068] Figure 7 shows characteristic curves of an elastic wave device according to an embodiment of the present application and a conventional elastic wave device. The solid line in Figure 7 is the characteristic curve of elastic wave device 500 , and the dashed line in Figure 7 is the characteristic curve of elastic wave device 600 .

[0069] Referring to FIG. 7 , at frequencies around 1400 MHz and 2100 MHz, the high-order modal responses of elastic wave device 600 are significantly greater than those of elastic wave device 500. This demonstrates that the elastic wave device provided in accordance with embodiments of the present application can suppress high-order modal responses, thereby improving the electrical characteristics of the elastic wave device in higher-order modes.

[0070] In some embodiments, one or more functional layers may be provided between the second piezoelectric layer and the support substrate. For example, in some embodiments, a temperature compensation layer and / or an intermediate dielectric layer may be provided between the second piezoelectric layer and the support substrate.

[0071] FIG8 shows another elastic wave device according to an embodiment of the present application. As shown in FIG8 , the elastic wave device 800 includes an electrode 810 , a first piezoelectric layer 820 , a second piezoelectric layer 830 , a temperature compensation layer 840 , an intermediate dielectric layer 850 , and a support substrate 860 .

[0072] As shown in FIG. 8 , the electrode 810 is disposed above the first piezoelectric layer 820 , the first piezoelectric layer 820 is disposed above the second piezoelectric layer 830 , and the second piezoelectric layer 830 is disposed above the supporting substrate 840 .

[0073] The material of the electrode 810 can be an appropriate metal material such as aluminum (Al), copper (Cu), platinum (Pt), gold (Au), silver (Ag), titanium (Ti), nickel (Ni), chromium (Cr), molybdenum (Mo), or tungsten (W), or an alloy mainly composed of any of these metals. The electrode 810 may also have a structure formed by stacking multiple metal films composed of these metals or alloys.

[0074] The material of the first piezoelectric layer 820 and the second piezoelectric layer 830 can be lithium tantalate crystal or lithium niobate crystal. For example, in some embodiments, the material of the first piezoelectric layer 820 can be lithium tantalate single crystal. For another example, in other embodiments, the material of the first piezoelectric layer 820 can be lithium niobate single crystal. The material of the first piezoelectric layer 820 is the same as the material of the second piezoelectric layer 830. In other words, if the material of the first piezoelectric layer 820 is lithium niobate single crystal, then the material of the second piezoelectric layer 830 is also lithium niobate single crystal.

[0075] The Euler angle of the first piezoelectric layer 820 is different from the Euler angle of the second piezoelectric layer 830 .

[0076] The material of the temperature compensation layer 840 (also referred to as a temperature compensation film) may be silicon oxide.

[0077] The material of the intermediate dielectric layer 850 may be polysilicon.

[0078] The material of the support substrate 860 can be silicon, aluminum nitride, quartz, sapphire, spinel, etc.

[0079] FIG9 is a schematic diagram of a conventional elastic wave device. The elastic wave device shown in FIG9 only includes an electrode 910 , a piezoelectric layer 920 , a temperature compensation layer 930 , an intermediate dielectric layer 940 , and a support substrate 950 .

[0080] Figure 10 shows characteristic curves of an elastic wave device according to an embodiment of the present invention and a conventional elastic wave device. The solid line in Figure 10 is the characteristic curve of elastic wave device 800 , and the dashed line in Figure 10 is the characteristic curve of elastic wave device 900 .

[0081] Referring to Figure 10 , at 1300 MHz and 2000 MHz, the high-order modal response of elastic wave device 900 is significantly greater than that of elastic wave device 800. In particular, at 2000 MHz, the response of elastic wave device 800 is essentially eliminated. This indicates that the elastic wave device provided in accordance with the embodiments of the present application can suppress high-order modal responses, thereby improving the electrical characteristics of the elastic wave device in higher-order modes.

[0082] In addition, a temperature compensation layer is introduced into elastic wave device 800 in Figure 8. The temperature coefficient of the temperature compensation layer has a sign opposite to that of the first and second piezoelectric layers, thereby reducing frequency deviation caused by temperature changes.

[0083] The electrodes (e.g., electrode 210, electrode 510, or electrode 810) in the elastic wave device provided in the embodiments of the present application are configured to generate elastic waves having a wavelength λ. The elastic waves may be Rayleigh waves, Lamb waves, or shear horizon waves (SH waves).

[0084] In some embodiments, the wavelength λ can be determined by the period of the electrode fingers in the electrode. Take a SAW filter as an example. Figure 11 is a schematic diagram of the electrodes of a SAW filter. The electrodes in a SAW filter can also be called interdigitated (IDT) electrodes. As shown in Figure 11, the IDT electrode 1100 includes a first bus bar 1111, a second bus bar 1121, a plurality of first electrode fingers 1112, and a plurality of second electrode fingers 1122. The IDT electrode 1100 can be arranged on the upper surface of a first piezoelectric layer (e.g., the first piezoelectric layer 220, the first piezoelectric layer 520, or the first piezoelectric layer 820).

[0085] First bus bar 1111 is formed in an elongated shape with its longitudinal direction being the second direction, and is electrically connected to a plurality of first electrode fingers 1112. Second bus bar 1121 is formed in an elongated shape with its longitudinal direction being the second direction, and is electrically connected to a plurality of second electrode fingers 1122. The second direction is a direction orthogonal to the first direction.

[0086] Multiple first electrode fingers 1112 are arranged in parallel with each other in the second direction. Each first electrode finger 1112 is formed into a strip with the third direction as its longitudinal direction. Multiple first electrode fingers 1112 are arranged in parallel, facing each other in the second direction. Multiple second electrode fingers 1122 are arranged in parallel, facing each other in the second direction. Each second electrode finger 1122 is formed into a strip with the third direction as its longitudinal direction. Multiple second electrode fingers 1122 are arranged in parallel, facing each other in the second direction. Multiple first electrode fingers 1112 and multiple second electrode fingers 1122 are arranged alternately, one at a time. The third direction is a direction orthogonal to both the first and second directions.

[0087] The electrode finger period of the IDT electrode 1100 is the distance between the corresponding sides of adjacent first and second electrode fingers 1112, 1122. As shown in Figure 12, the electrode finger period of the IDT electrode 1100 is defined by the sum (W1+S1) of the width W1 of the first and second electrode fingers 1112, 1122, and the spacing width S1 between adjacent first and second electrode fingers 1112, 1122. In the IDT electrode 1100, the duty cycle, or the value obtained by dividing the electrode finger width W1 by the electrode finger period, is defined by W1 / (W1+S1). The duty cycle is, for example, 0.5. The wavelength λ of the elastic wave specified by the electrode finger period of the IDT electrode 1100 is defined by the repetition period P1 of the plurality of first and second electrode fingers 1112, 1122.

[0088] The elastic wave device provided in the embodiments of the present application includes two piezoelectric layers, namely a first piezoelectric layer and a second piezoelectric layer. Because the first piezoelectric layer is disposed above the second piezoelectric layer, in some cases, the first piezoelectric layer may also be referred to as an upper piezoelectric layer, and the second piezoelectric layer may also be referred to as a lower piezoelectric layer.

[0089] As described above, in the embodiments of the present application, the thicknesses of the first piezoelectric layer and the second piezoelectric layer (e.g., the first piezoelectric layer 220 and the second piezoelectric layer 230, the first piezoelectric layer 520 and the second piezoelectric layer 530, or the first piezoelectric layer 820 and the second piezoelectric layer 830) are different. In some embodiments, the thickness of the first piezoelectric layer is less than the thickness of the second piezoelectric layer. For example, the ratio of the thickness of the first piezoelectric layer to the second piezoelectric layer may be 1:2. For another example, the ratio of the thickness of the first piezoelectric layer to the second piezoelectric layer may be approximately 1:2. For example, it may be 1.1:2, 1.2:2, 1.05:2, or 1.3:2, etc.

[0090] In some embodiments, the sum of the thickness of the first piezoelectric layer and the thickness of the second piezoelectric layer is less than or equal to 0.4λ. For example, in some embodiments, the thickness of the first piezoelectric layer may be 0.1λ, and the thickness of the second piezoelectric layer may be 0.2λ.

[0091] As described above, in the embodiment of the present application, the Euler angles of the first piezoelectric layer and the second piezoelectric layer (e.g., the first piezoelectric layer 220 and the second piezoelectric layer 230, the first piezoelectric layer 520 and the second piezoelectric layer 530, or the first piezoelectric layer 820 and the second piezoelectric layer 830) are different. Assume that the Euler angle of the first piezoelectric layer is expressed as Then the Euler angle of the second piezoelectric layer can be For example, if the Euler angles of the first piezoelectric layer are (0, -48, 0), the Euler angles of the second piezoelectric layer may be (0, 142, 180).

[0092] As described above, in the embodiments of the present application, the piezoelectric constant tensors of the first piezoelectric layer and the second piezoelectric layer (e.g., the first piezoelectric layer 220 and the second piezoelectric layer 230, the first piezoelectric layer 520 and the second piezoelectric layer 530, or the first piezoelectric layer 820 and the second piezoelectric layer 830) have different signs. For example, in some embodiments, the piezoelectric constant tensor can be expressed as e15, e24, e31, e32, or e33, etc. If the sign of the piezoelectric constant tensor of the first piezoelectric layer is positive, the sign of the piezoelectric constant tensor of the second piezoelectric layer is negative; if the sign of the piezoelectric constant tensor of the first piezoelectric layer is negative, the sign of the piezoelectric constant tensor of the first piezoelectric layer is positive.

[0093] In some embodiments, the thickness of an electrode (e.g., electrode 210, electrode 510, or electrode 810) in an elastic wave device provided by embodiments of the present application can be greater than or equal to 0.03λ and less than or equal to 0.12λ. For example, in some embodiments, the thickness of the electrode can be 0.08λ, 0.10λ, 0.12λ, etc.

[0094] In some embodiments, when the elastic wave device includes a supporting substrate (eg, elastic wave device 500 or elastic wave device 800 ), the velocity of the elastic wave of the supporting substrate is greater than the velocity of the elastic wave of the first piezoelectric layer and the second piezoelectric layer.

[0095] In some embodiments, the velocity of the elastic wave supporting the substrate is less than 6500 m / s.

[0096] In some embodiments, when an elastic wave device includes a temperature compensation layer (eg, elastic wave device 800 ), the speed of the elastic waves of the temperature compensation layer is lower than the speed of the elastic waves of the first and second piezoelectric layers.

[0097] Table 1 and Table 2 show the piezoelectric tensors of two piezoelectric layers included in an elastic wave device provided according to an embodiment of the present application.

[0098] Table 1

[0099] Table 2

[0100] Table 1 shows the piezoelectric tensor of the first piezoelectric layer (assuming the Euler angle of the first piezoelectric layer is (0, -48, 0)). Table 2 shows the piezoelectric tensor of the second piezoelectric layer (assuming the Euler angle of the second piezoelectric layer is (0, 132, 180)). It can be seen that the piezoelectric tensor of the first piezoelectric layer and the piezoelectric tensor of the second piezoelectric layer are both represented by a 3×6 matrix. The 3×6 matrix of the first piezoelectric layer corresponds one-to-one to the 3×6 matrix of the second piezoelectric layer. The absolute values ​​of the corresponding values ​​in the matrix are the same, but the signs of some values ​​are opposite. For example, the value in the third row of the first column of Table 1 is -1.5295, while the value in the third row of the first column of Table 2 is 1.5295.

[0101] An embodiment of the present application further provides a circuit, which may include one or more elastic wave devices provided in an embodiment of the present application. For example, the circuit includes one or more elastic wave devices 200. For another example, the circuit includes one or more elastic wave devices 500. For another example, the circuit includes one or more elastic wave devices 800. The circuit can be applied to an electronic device. For example, assuming that the electronic device is the electronic device 100 shown in Figure 1. Then the circuit can be located in the communication module 130 of the electronic device 100.

[0102] The present application also provides an electronic device including the aforementioned circuit. The electronic device may be the electronic device 100 shown in FIG1 . The electronic device may also be a network device, an Internet of Things device, an electric vehicle, a hybrid electric vehicle, a drone, or the like.

[0103] Those skilled in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0104] Those skilled in the art will clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0105] In the several embodiments provided in this application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are merely schematic. For example, the division of the units is merely a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0106] The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of these units may be selected to achieve the purpose of this embodiment according to actual needs.

[0107] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0108] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application, or the part that contributes to the prior art, or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for enabling a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk.

[0109] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of this application. Therefore, the scope of protection of this application should be based on the scope of protection of the claims.

Claims

1. An elastic wave device, characterized in that: comprising electrodes, a first piezoelectric layer, and a second piezoelectric layer, wherein The electrode is disposed on the first piezoelectric layer, the electrode being configured to generate an elastic wave having a wavelength λ; The first piezoelectric layer is arranged on the second piezoelectric layer, wherein the Euler angle of the first piezoelectric layer is different from the Euler angle of the second piezoelectric layer, the material of the first piezoelectric layer is the same as the material of the second piezoelectric layer, and the material of the first piezoelectric layer and the second piezoelectric layer is lithium tantalate or lithium niobate.

2. The elastic wave device according to claim 1, wherein The thickness of the first piezoelectric layer is smaller than the thickness of the second piezoelectric layer.

3. The elastic wave device according to claim 2, wherein The ratio of the thickness of the first piezoelectric layer to the thickness of the second piezoelectric layer is 1:

2.

4. The elastic wave device according to any one of claims 1 to 3, wherein The sum of the thickness of the first piezoelectric layer and the thickness of the second piezoelectric layer is less than or equal to 0.4λ.

5. The elastic wave device according to any one of claims 1 to 4, wherein The Euler angle of the first piezoelectric layer is The Euler angle of the second piezoelectric layer is 6. The elastic wave device according to any one of claims 1 to 5, wherein: The sign of the piezoelectric constant tensor of the first piezoelectric layer is different from the sign of the piezoelectric constant tensor of the second piezoelectric layer.

7. The elastic wave device according to any one of claims 1 to 6, wherein: The thickness of the electrode is greater than or equal to 0.03λ and less than or equal to 0.12λ.

8. The elastic wave device according to any one of claims 1 to 7, wherein The elastic wave device further includes a supporting substrate located below the second piezoelectric layer, wherein a velocity of elastic waves of the supporting substrate is greater than a velocity of elastic waves of the first piezoelectric layer and the second piezoelectric layer.

9. The elastic wave device according to claim 8, wherein The elastic wave device further includes a temperature compensation layer located between the second piezoelectric layer and the supporting substrate. The sign of the temperature coefficient of the temperature compensation layer is opposite to the signs of the temperature coefficients of the first piezoelectric layer and the second piezoelectric layer.

10. The elastic wave device according to claim 9, wherein A speed of elastic waves of the temperature compensation layer is smaller than a speed of elastic waves of the first piezoelectric layer and the second piezoelectric layer.

11. The elastic wave device according to claim 9 or 10, wherein: The elastic wave further includes an intermediate dielectric layer, and the intermediate dielectric layer is located between the temperature compensation layer and the supporting substrate.

12. A circuit, characterized in that: The circuit includes the elastic wave device according to any one of claims 1 to 11.

13. A communication device, characterized in that: The communication device comprises the circuit of claim 12.

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