Elastic wave device, circuit, and electronic device

Abstract

The embodiment of the invention provides an elastic wave device, a circuit and an electronic device. The elastic wave device includes an electrode, a thin film, and a substrate. The electrode is arranged on the thin film and is used for generating elastic waves with the wavelength of lambda. The thin film is disposed on the substrate, and the thin film is made of lithium tantalate or lithium niobate. In the case where the thin film is made of the lithium tantalate, the composition ratio of Li to Ta satisfies 48.8: 51.2 < = Li: Ta < = 51.2: 48.8. When the thin film is prepared from the lithium niobate, the composition ratio of Li to Nb satisfies that Li: Nb is more than or equal to 48.8: 51.2 and less than or equal to 51.2: 48.8. The elastic wave device provided by the embodiment of the invention has the characteristics of higher sound velocity, larger electromechanical coupling coefficient and smaller frequency temperature coefficient, and has better characteristics compared with an elastic device using a common single crystal wafer with the same components. Meanwhile, the manufacturing cost of the elastic wave device provided by the invention is lower than that of a large substrate using non-general stoichiometry.

Description

Technical Field

[0001] This application relates to the field of electronic engineering, and more specifically, to an elastic wave device, circuit, and electronic device. Background Technology

[0002] Elastic wave devices are widely used in devices such as resonators and filters. For example, surface acoustic wave (SAW) filters are a common type of elastic wave device. SAW filters are special filter devices made using piezoelectric materials such as quartz crystals and piezoelectric ceramics, utilizing the piezoelectric effect of these materials and the physical properties of surface acoustic wave propagation. SAW filters are widely used in mobile communications. For example, filters in the radio frequency (RF) circuits of mobile terminals may include SAW filters. Summary of the Invention

[0003] This application provides an elastic wave device, circuit, and electronic device with characteristics such as faster sound speed, larger electromechanical coupling coefficient (k2), smaller temperature coefficient of frequency (TCF), and better overall performance.

[0004] In a first aspect, embodiments of this application provide an elastic wave device. The elastic wave device includes an electrode, a thin film, and a substrate. The electrode is disposed on the thin film and is used to generate an elastic wave with a wavelength of λ. The thin film is disposed on the substrate and is made of lithium tantalate or lithium niobate. When the thin film is made of lithium tantalate, the composition ratio of Li to Ta satisfies: 48.8:51.2≤Li:Ta≤51.2:48.8. When the thin film is made of lithium niobate, the composition ratio of Li to Nb satisfies: 48.8:51.2≤Li:Nb≤51.2:48.8.

[0005] According to the embodiments provided in this application, the elastic wave device has a thin film with a composition closer to the stoichiometric composition (S-composition), which is disposed on a substrate having the same composition (C-composition). This elastic wave device exhibits characteristics such as faster sound velocity, a larger electromechanical coupling coefficient (k2), and a smaller temperature coefficient of frequency (TCF), and possesses better characteristics compared to elastic devices using general single-crystal wafers with the same composition. Furthermore, the manufacturing cost of the elastic wave device proposed in this application is lower than that using bulk substrates with non-general stoichiometric composition.

[0006] In one possible design, when the film is made of lithium tantalate, the composition ratio of Li to Ta also satisfies: 49:51≤Li:Ta≤51:49; and when the film is made of lithium niobate, the composition ratio of Li to Nb also satisfies: 49:51≤Li:Nb≤51:49.

[0007] The above technical solutions can further improve the performance of elastic wave devices.

[0008] In one possible design, the thin film is a monocrystalline film or an epitaxial film.

[0009] The above technical solutions can further improve the performance of elastic wave devices.

[0010] In one possible design, the thickness of the film is greater than or equal to 0.3λ.

[0011] The above technical solutions can further improve the performance of elastic wave devices.

[0012] In one possible design, the thickness of the film is less than 1.5λ.

[0013] The above technical solutions can further improve the performance of elastic wave devices.

[0014] In one possible design, the elastic wave device also includes a dielectric film formed to cover the electrode.

[0015] The above technical solutions can further improve the performance of elastic wave devices.

[0016] In one possible design, the thickness of the dielectric film is greater than 0.09λ.

[0017] The above technical solutions can further improve the performance of elastic wave devices.

[0018] In one possible design, the thickness of the dielectric film is less than 0.23λ.

[0019] The above technical solutions can further improve the performance of elastic wave devices.

[0020] In one possible design, the electrode is made of a material whose main component has a higher density than Al.

[0021] The above technical solutions can further improve the performance of elastic wave devices.

[0022] In one possible design, the electrode is made of a material whose main component is Cu.

[0023] The above technical solutions can further improve the performance of elastic wave devices.

[0024] In one possible design, the Euler angle of the substrate is...

[0025] The above technical solutions can further improve the performance of elastic wave devices.

[0026] In one possible design, the difference between the crystal orientation of the substrate and the crystal orientation of the thin film is within ±1.5°.

[0027] The above technical solutions can further improve the performance of elastic wave devices.

[0028] In one possible design, the Rayleigh wave is the main propagating wave of the elastic wave device.

[0029] The above technical solutions can further improve the performance of elastic wave devices.

[0030] Secondly, embodiments of this application provide a circuit. This circuit includes an elastic wave device according to the first aspect or any possible design of the first aspect.

[0031] Thirdly, embodiments of this application provide an electronic device. This electronic device includes the circuitry according to the second aspect. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the structure of electronic device 100.

[0033] Figure 2 An elastic wave device according to some embodiments of this application is shown.

[0034] Figure 3 The admittance characteristics of four elastic wave devices with different film thicknesses are shown.

[0035] Figure 4 The k2 of four elastic wave devices with different film thicknesses is shown.

[0036] Figure 5 The admittance ratios of four elastic wave devices with different film thicknesses are shown.

[0037] Figure 6 An elastic wave device according to some embodiments of this application is shown.

[0038] Figure 7 An elastic wave device without a thin film is shown.

[0039] Figure 8 The admittance characteristics of the elastic wave device 600 are shown.

[0040] Figure 9 The admittance characteristics of the elastic wave device 700 are shown.

[0041] Figure 10 The relationship between the thickness of the thin film and the electromechanical coupling coefficient (k2) is shown.

[0042] Figure 11 The relationship between the film thickness and the admittance ratio is shown.

[0043] Figure 12 The relationship between the thickness of the dielectric film and the electromechanical coupling coefficient (k2) is shown.

[0044] Figure 13 The relationship between the thickness of the dielectric film and the admittance ratio is shown.

[0045] Figure 14 This is a schematic diagram of the electrodes of a SAW filter.

[0046] Figure 15 This is a schematic diagram of the electrodes of a SAW filter. Detailed Implementation

[0047] The technical solution of this application will now be described with reference to the accompanying drawings.

[0048] The terms "first," "second," etc., used below are for descriptive purposes only and should not be construed as indicating or implying relative importance, or implicitly indicating the number of technical features indicated. Therefore, the features defined by "first" and "second" may explicitly or implicitly include one or more features.

[0049] Furthermore, in this application, directional terms such as "up," "down," "left," "right," "horizontal," and "vertical" are defined relative to the placement of the components shown in the accompanying drawings. It should be understood that these directional terms are relative concepts used to describe and clarify relativity, and may change accordingly as the placement of the components in the accompanying drawings changes.

[0050] The term "at least one" as used in this document refers to one or more items, and "multiple" refers to two or more items. "And / or" describes the relationship between related objects, indicating that there can be three relationships. For example, A and / or B can indicate the following: "A only", "Both A and B are included", and "B only", where A and B can be singular or plural. The character " / " generally indicates that the related objects are in an OR relationship. "At least one of the following" or similar expressions refer to any combination of these items, including single items or any combination of multiple items. For example, "at least one of a, b, or c" can mean: "a, b, c", "a and b", "a and c", "b and c", or "a, b, and c", where a, b, and c can be single or multiple forms.

[0051] It is understood that the following description is merely an embodiment and is not intended to be limiting. For example, in the following description, placing the second component above or on the first component may include embodiments in which the first and second components are in direct contact with each other, or it may include situations in which other components are placed directly between the first and second components by means of an adhesive, such that the first and second components in this embodiment cannot be in direct contact.

[0052] The elastic wave device in the embodiments of this application can be a filter (e.g., a surface acoustic wave filter (SAW), a bulk acoustic wave (BAW) filter), a resonator (e.g., a SAW resonator, a BAW resonator), a duplexer, a dual-signal device, etc.

[0053] For example, Figure 1 This is a schematic diagram of the structure of electronic device 100.

[0054] Electronic device 100 may include processor 110, memory 120, communication module 130 and antenna 131.

[0055] It is understood that the structures illustrated in the embodiments of this application do not constitute a specific limitation on the electronic device 100. In other embodiments of this application, the electronic device 100 may include more or fewer components than illustrated, or combine some components, or split some components, or have different component arrangements. The illustrated components may be implemented in hardware, software, or a combination of software and hardware.

[0056] Processor 110 may include one or more processing units, such as: application processor (AP), modem processor, graphics processing unit (GPU), image signal processor (ISP), controller, memory, video codec, digital signal processor (DSP), baseband processor, and / or neural network processing unit (NPU), etc. Different processing units may be independent devices or integrated into one or more processors.

[0057] The processor 110 may also include a memory for storing instructions and data. In some embodiments, the memory in the processor 110 is a cache memory. This memory can store instructions or data that the processor 110 has just used or that are used repeatedly. If the processor 110 needs to use the instruction or data again, it can retrieve it directly from the memory. This avoids repeated accesses, reduces the waiting time of the processor 110, and thus improves the efficiency of the system.

[0058] In some embodiments, the processor 110 may include one or more interfaces. Interfaces may include an inter-integrated circuit (I2C) interface, an inter-integrated circuit sound (I2S) interface, a pulse code modulation (PCM) interface, a universal asynchronous receiver / transmitter (UART) interface, a mobile industry processor interface (MIPI), a general-purpose input / output (GPIO) interface, a subscriber identity module (SIM) interface, and / or a universal serial bus (USB) interface, etc.

[0059] The wireless communication function of the electronic device 100 can be realized through the communication module 130, antenna 131, modem processor and baseband processor, etc.

[0060] Antenna 131 is used to transmit and receive electromagnetic wave signals. Antenna 131 can be used to cover one or more communication frequency bands. In some embodiments, the antenna can be used in conjunction with a tuning switch.

[0061] The communication module 130 can provide solutions for wireless communication, including 2G / 3G / 4G / 5G, applied to the electronic device 100. The communication module 130 may include at least one filter, switch, power amplifier, low-noise amplifier (LNA), etc. The communication module 130 can receive electromagnetic waves via the antenna 131, and perform filtering, amplification, and other processing on the received electromagnetic waves before transmitting them to the modem processor for demodulation. The mobile communication module 150 can also amplify the signal modulated by the modem processor and convert it into electromagnetic waves for radiation via the antenna 131. In some embodiments, at least some functional modules of the communication module 130 may be housed in the processor 110. In some embodiments, at least some functional modules of the communication module 130 and at least some modules of the processor 110 may be housed in the same device.

[0062] The modem processor may include a modulator and a demodulator. The modulator modulates a low-frequency baseband signal to be transmitted into a mid-to-high frequency signal. The demodulator demodulates a received electromagnetic wave signal into a low-frequency baseband signal. The demodulator then transmits the demodulated low-frequency baseband signal to the baseband processor for processing. After processing by the baseband processor, the low-frequency baseband signal is transmitted to the application processor. The application processor outputs sound signals through audio devices (e.g., speakers, receivers, etc.) or displays images or videos on a display screen. In some embodiments, the modem processor may be a separate device. In other embodiments, the modem processor may be independent of the processor 110 and may be housed in the same device as the communication module 130 or other functional modules.

[0063] The communication module 130 can also provide solutions for wireless communication applications on the electronic device 100, including wireless local area networks (WLANs) (such as wireless fidelity (Wi-Fi) networks), Bluetooth (BT), global navigation satellite system (GNSS), frequency modulation (FM), near field communication (NFC), and infrared (IR) technologies. The communication module 130 can be one or more devices integrating at least one communication processing module. The communication module 130 receives electromagnetic waves via antenna 131, performs frequency modulation and filtering of the electromagnetic wave signals, and sends the processed signal to processor 110. The communication module 130 can also receive signals to be transmitted from processor 110, perform frequency modulation and amplification, and convert them into electromagnetic waves for radiation via antenna 131.

[0064] Antenna 131 and communication module 130 are coupled, enabling electronic device 100 to communicate with networks and other devices via 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), BT, GNSS, WLAN, NFC, FM, and / or IR technologies. The GNSS may include Global Positioning System (GPS), Global Navigation Satellite System (GLONASS), BeiDou Navigation Satellite System (BDS), Quasi-Zenith Satellite System (QZSS), and / or Satellite Based Augmentation Systems (SBAS).

[0065] Figure 2 An elastic wave device according to some embodiments of this application is shown. See also Figure 2 The elastic wave device 200 includes an electrode 210, a thin film 220, and a substrate 230.

[0066] like Figure 2 As shown, electrode 210 is disposed on thin film 220, and thin film 220 is disposed on substrate 230.

[0067] In some embodiments, the electrode 210 may be made of aluminum (Al), copper (Cu), platinum (Pt), gold (Au), silver (Ag), titanium (Ti), nickel (Ni), chromium (Cr), molybdenum (Mo), or tungsten (W), or any suitable metallic material, such as an alloy mainly composed of any of these metals.

[0068] In some embodiments, electrode 210 is made of a material whose main component has a density higher than that of Al. For example, electrode 210 may be made of Cu, Pt, Mo, W, etc.

[0069] In some embodiments, electrode 210 may also have a structure consisting of multiple metal film layers made of the aforementioned metals or alloys. For example, electrode 210 may include two metal film layers. For convenience, these two metal film layers may be referred to as the first metal film layer and the second metal film layer, respectively. The second metal film layer serves as an adhesive layer under the first metal film layer. In some embodiments, the first metal film layer is made of Cu, while the second metal film layer is made of Ti or Cr. The main component of the electrode is Cu.

[0070] The materials of the thin film 220 and the substrate 230 can be lithium tantalate or lithium niobate.

[0071] In some embodiments, the material of the thin film 220 may be different from the material of the substrate 230. For example, the thin film 220 may be made of lithium tantalate, while the substrate 230 may be made of lithium niobate.

[0072] In some other embodiments, the material of the thin film 220 is the same as that of the substrate 230. For example, both the thin film 220 and the substrate 230 are made of lithium tantalate.

[0073] The substrate 230 can be a single-crystal substrate of c composition. For example, the substrate 230 can be prepared by conventional Czochralski (Cz) methods, etc., and this application is not limited thereto.

[0074] For component c, the ratio of Li to Nb in lithium niobate (LiNbO3, LN) is: The composition ratio of Li to Ta in lithium tantalate (LiTabO3, LT) is as follows: In other words, when the substrate 230 is made of lithium niobate, the composition ratio of Li to Nb also satisfies: 48.2:51.8≤Li:Nb<48.8:51.2; when the substrate 230 is made of lithium tantalate, the composition ratio of Li to Ta also satisfies: 48.2:51.8≤Li:Ta<48.8:51.2.

[0075] For the S composition, when the substrate 230 is made of lithium niobate, the composition ratio of Li to Nb satisfies: Li:Nb = 50:50; when the substrate 230 is made of lithium tantalate, the composition ratio of Li to Ta satisfies: Li:Ta = 50:50.

[0076] The composition of film 220 is closer to that of s. For compositions closer to s, when film 220 is made of lithium tantalate, the composition ratio of Li to Ta satisfies: 48.8:51.2≤Li:Ta≤51.2:48.8; when film 220 is made of lithium niobate, the composition ratio of Li to Nb satisfies: 48.8:51.2≤Li:Nb≤51.2:48.8.

[0077] In some embodiments, the thin film 220 may be a single-crystal film or an epitaxial film. The thin film 220 may be formed on the substrate 230 by a co-epitaxial growth technique using physical vapor deposition (PVD) or chemical vapor deposition (CVD). The crystal orientation of the thin film 220 substantially coincides with the crystal orientation of the substrate 230.

[0078] In some embodiments, the Euler angle of the substrate 230 is

[0079] In some embodiments, the difference between the crystal orientation of the substrate 230 and the crystal orientation of the thin film 220 is within ±1.5°. Ideally, the difference between the crystal orientation of the substrate 230 and the crystal orientation of the thin film 220 is 0.

[0080] In some embodiments, the Rayleigh wave is the main propagation wave of the elastic wave device.

[0081] In some other embodiments, the main propagation wave of the elastic wave device 200 may be a Lamb wave or a horizontal shear wave.

[0082] Comparing LT and LN with s-components and c-components, the s-component exhibits faster sound velocity, a larger electromechanical coupling coefficient (k²), a smaller temperature coefficient of frequency (TCF), and other superior properties. However, in the Cz method, fabricating a substrate with the s-component is unstable and costly. According to embodiments provided in this application, the elastic wave device has a thin film with a composition closer to the s-component, disposed on a substrate with the c-component, achieving performance close to that of an elastic wave device with an s-component substrate. The elastic wave device proposed in this application has a lower manufacturing cost compared to the elastic wave device with an s-component substrate.

[0083] Figure 3The admittance characteristics of four elastic wave devices with different film thicknesses are shown. s-LN(0λ) / c-LN represents an elastic wave device with a film thickness of 0λ. In other words, LN(0λ) / c-LN is a conventional elastic wave device with a c-composition substrate, which does not have the film provided in this application. s-LN(0.3λ) / c-LN represents an elastic wave device with a film thickness of 0.3λ. s-LN(0.5λ) / c-LN represents an elastic wave device with a film thickness of 0.5λ, and s-LN(1λ) / c-LN represents an elastic wave device with a film thickness of 1λ. λ is the wavelength of the elastic wave device.

[0084] Figure 4 The k2 of four elastic wave devices with different film thicknesses is shown.

[0085] Figure 5 The admittance ratios of four elastic wave devices with different film thicknesses are shown.

[0086] based on Figures 3 to 5 The elastic wave device provided in this application is superior to elastic wave devices obtained using conventional c-composition substrates.

[0087] from Figure 4 It can be seen that k2 increases as the film thickness increases. Figure 5 It can be seen that the admittance ratio is also improved by forming a thin film. However, considering that the peak value of the admittance ratio is close to 0.5λ, and the admittance ratio is worse the thicker the layer, preferably, the thickness of the thin film is equal to or greater than 0.3λ and equal to or less than 1.5λ.

[0088] Figure 6 An elastic wave device according to some embodiments of this application is shown. See also Figure 6 The elastic wave device 600 includes an electrode 610, a thin film 620, and a substrate 630. Detailed information regarding the electrode 610, thin film 620, and substrate 630 can be found in the above embodiments and will not be repeated here. Similar to the elastic wave device 200, the main propagation wave of the elastic wave device 600 can be a Rayleigh wave, a Lamb wave, a horizontal shear wave, etc.

[0089] and Figure 2 Compared to the elastic wave device 200 shown, the elastic wave device 600 further includes a dielectric film 640. The dielectric film 640 covers the electrode 610. The dielectric film 640 can further improve the characteristics of the elastic wave device.

[0090] Figure 7 An elastic wave device without a thin film is shown. See also Figure 7 The elastic wave device 700 includes an electrode 710, a dielectric film 720, and a substrate 730. Compared with the elastic wave device 600, the elastic wave device 700 does not include a thin film.

[0091] Figure 8 The admittance characteristics of the elastic wave device 600 are shown. Figure 8 The corresponding elastic wave device 600 satisfies the following parameters: λ = 4.5 μm, the electrode 610 thickness is 290 nm, the thin film 620 thickness is 1λ, the substrate 630 thickness is >6λ, and the dielectric film 640 thickness is 1300 nm. Furthermore, the electrode 610 is made of Cu, the dielectric film 640 is made of SiO2, and both the substrate 630 and the thin film 620 are 126° rotated Y-cut LN (expressed in Euler angles).

[0092] Figure 9 The admittance characteristics of the elastic wave device 700 are shown. Figure 9 The corresponding elastic wave device 700 satisfies the following parameters: λ = 4.5 μm, electrode 710 thickness is 290 nm, substrate 730 thickness > 7λ, and dielectric film 720 thickness is 1300 nm. Furthermore, electrode 710 is made of Cu, dielectric film 720 is made of SiO2, and substrate 730 is a 127.5° rotated Y-cut LN (expressed in Euler angles).

[0093] based on Figure 8 and Figure 9 It can be observed that the elastic wave device with thin film has a higher electromechanical coupling coefficient (k2) and a larger admittance ratio (Y ratio).

[0094] In some embodiments, the thickness of the film is greater than or equal to 0.3λ (hereinafter referred to as Condition 1).

[0095] In some embodiments, the thickness of the film is less than 1.5λ (hereinafter referred to as condition 2).

[0096] In some embodiments, the thickness of the film can satisfy conditions 1 and 2. In other words, the thickness of the film can be greater than or equal to 0.3λ, and the thickness of the film can be less than 1.5λ.

[0097] Figure 10 The relationship between the thickness of the thin film and the electromechanical coupling coefficient (k2) is shown.

[0098] Figure 11 The relationship between the film thickness and the admittance ratio is shown.

[0099] like Figure 10 As shown, when the film thickness is 0.3λ or greater, the value of k2 becomes almost constant. Furthermore, from... Figure 11It can be seen that the admittance ratio is almost stable when the film thickness is 0.2λ or greater. Therefore, good characteristics can be stably obtained by setting the film thickness to 0.3λ or greater. Furthermore, when the film thickness becomes 1.5λ or greater, the effect of film surface roughness on wave propagation is not negligible, and the insertion loss decreases slightly.

[0100] In some embodiments, when the elastic wave device includes a dielectric film, the thickness of the dielectric film is greater than 0.09λ (hereinafter referred to as condition 3).

[0101] In some embodiments, when the elastic wave device includes a dielectric film, the thickness of the dielectric film is less than 0.23λ (hereinafter referred to as condition 4).

[0102] In some embodiments, when the elastic wave device includes a dielectric film, the thickness of the dielectric film can satisfy conditions 3 and 4. In other words, the thickness of the dielectric film can be greater than 0.09λ and less than 0.23λ.

[0103] Figure 12 The relationship between the thickness of the dielectric film and the electromechanical coupling coefficient (k2) is shown.

[0104] Figure 13 The relationship between the thickness of the dielectric film and the admittance ratio is shown.

[0105] like Figure 12 As shown, by setting the thickness of the dielectric film to 0.04λ or greater, or 0.26λ or less, compared with... Figure 3 Compared to the case of a conventional c-component single-crystal substrate, k2 is increased by more than 10%. Furthermore, regarding the admittance ratio, a better value can be obtained compared to using a conventional c-component single-crystal substrate when the dielectric film thickness is 0.3λ or less.

[0106] Optionally, by increasing the thickness t of the dielectric film SiO2 Set to 0.09λ <t SiO2 With a value <0.23λ, high k2 and impedance ratio can be stably achieved.

[0107] In some implementation examples, the wavelength λ can be determined by the electrode spacing in the electrodes. Take a SAW filter as an example. Figure 14 This is a schematic diagram of the electrodes in a SAW filter. The electrodes in a SAW filter can also be called interdigital transducer (IDT) electrodes. Figure 14 As shown, the IDT electrode 1400 includes a first bus 1411, a second bus 1421, a plurality of first electrode fingers 1412, and a plurality of second electrode fingers 1422. The IDT electrode 1400 can be disposed on the upper surface of the thin film.

[0108] The first busbar 1411 is formed as a strip with the second direction as its long side and is electrically connected to a plurality of first electrode fingers 1412. The second busbar 1421 is formed as a strip with the second direction as its long side and is electrically connected to a plurality of second electrode fingers 1422. The second direction is orthogonal to the first direction. The plurality of first electrode fingers 1412 are arranged along the second direction. Each first electrode finger 1412 is formed as a strip with the third direction as its long side. The plurality of first electrode fingers 1412 are arranged in parallel relative to each other in the second direction. The plurality of second electrode fingers 1422 are arranged along the second direction. Each second electrode finger 1422 is formed as a strip with the third direction as its long side. The plurality of second electrode fingers 1422 are arranged in parallel relative to each other in the second direction. The plurality of first electrode fingers 1412 and the plurality of second electrode fingers 1422 are arranged alternately in sequence. The third direction is orthogonal to both the first and second directions. The electrode spacing of the IDT electrode 1400 is the distance between the corresponding edges of adjacent first electrode fingers 1412 and second electrode fingers 1422. For example... Figure 15 As shown, the electrode spacing of the IDT electrode 1400 is defined by the sum (W1+S1) of the width W1 of the first electrode finger 1412 and the spacing S1 between adjacent first electrode fingers 1412 and second electrode fingers 1422. In the IDT electrode 1400, the duty cycle is defined as W1 / (W1+S1) of the electrode finger width W1 divided by the electrode spacing, for example, 0.5. The wavelength λ of the sound wave, determined by the electrode spacing of the IDT electrode 1400, is defined by the repetition period P1 of the plurality of first electrode fingers 1412 and the plurality of second electrode fingers 1422.

[0109] This application provides a circuit. The circuit includes at least one of the aforementioned elastic wave devices. For example, the circuit may include one or more elastic wave devices 200; the circuit may include one or more elastic wave devices 600; or the circuit may include at least one elastic wave device 200 and at least one elastic wave device 600.

[0110] This application provides an electronic device that includes the circuit described above. The electronic device can be a terminal, such as a mobile phone terminal, tablet computer, laptop computer, augmented reality (AR) device, virtual reality (VR) device, vehicle terminal, digital camera, digital video recorder, action camera, security camera, etc., and can also be a server, etc.

[0111] The above descriptions are merely some specific implementations of this application and are not intended to limit the scope of protection of this application. Any variations or substitutions that are readily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. An elastic wave device, characterized in that, Includes electrodes, thin films, and substrates, among which, The electrode is disposed on the thin film, and the electrode is used to generate an elastic wave with a wavelength of λ. The thin film is disposed on the substrate, and the thin film is made of lithium tantalate or lithium niobate; When the thin film is made of lithium tantalate, the composition ratio of Li to Ta satisfies: 48.8:51.2≤Li:Ta≤51.2:48.8; When the thin film is made of lithium niobate, the composition ratio of Li to Nb satisfies: 48.8:51.2≤Li:Nb≤51.2:48.

8.

2. The elastic wave device according to claim 1, characterized in that, When the thin film is made of lithium tantalate, the composition ratio of Li to Ta also satisfies: 49:51≤Li:Ta≤51:49; When the film is made of lithium niobate, the composition ratio of Li to Nb also satisfies: 49:51≤Li:Nb≤51:

49.

3. The elastic wave device according to claim 1 or 2, characterized in that, The thin film is a single crystal film or an epitaxial film.

4. The elastic wave device according to any one of claims 1 to 3, characterized in that, The thickness of the film is greater than or equal to 0.3λ.

5. The elastic wave device according to any one of claims 1 to 4, characterized in that, The thickness of the film is less than 1.5λ.

6. The elastic wave device according to any one of claims 1 to 5, characterized in that, The elastic wave device also includes a dielectric film formed to cover the electrodes.

7. The elastic wave device according to claim 6, characterized in that, The thickness of the dielectric film is greater than 0.09λ.

8. The elastic wave device according to claim 6 or 7, characterized in that, The thickness of the dielectric film is less than 0.23λ.

9. The elastic wave device according to any one of claims 6 to 8, characterized in that, The electrode is made of a material whose main component has a higher density than Al.

10. The elastic wave device according to any one of claims 6 to 9, characterized in that, The electrode is made of a material whose main component is Cu.

11. The elastic wave device according to any one of claims 6 to 10, characterized in that, The Euler angles of the substrate are (φ,θ,ψ)=(0°±5°,36°±10°,0°±5°).

12. The elastic wave device according to any one of claims 1 to 11, characterized in that, The difference between the crystal orientation of the substrate and the crystal orientation of the thin film is within ±1.5°.

13. The elastic wave device according to any one of claims 1 to 12, characterized in that, Rayleigh wave is the main propagation wave of the elastic wave device.

14. A circuit, characterized in that, Includes the elastic wave device according to any one of claims 1 to 13.

15. An electronic device, characterized in that, Includes the circuit as described in claim 14.

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