Surface acoustic wave device structure and device

Abstract

The invention provides a surface acoustic wave device structure and device, the surface acoustic wave device structure comprises a substrate, and an IDT electrode and a load layer which are formed on the substrate, the IDT electrode comprises two interdigital electrodes which are oppositely arranged, each interdigital electrode comprises a bus bar and a plurality of electrodes, electrode fingers of different interdigital electrodes are arranged at intervals in a staggered manner, and the load layer is formed on the substrate. The load layer at least comprises a first part and a second part, the first part is arranged on the bus bar, and the second part is arranged on the electrode fingers, extends from the first part to one side of the centers of the electrode fingers and partially covers the electrode fingers. The load layer can enable the surface acoustic wave formed by excitation of the IDT electrode to be affected by the load layer to form a plurality of different sound velocity regions, and the propagation velocity of the surface acoustic wave at the position close to the end of the electrode finger is smaller than the propagation velocity of the surface acoustic wave at the corresponding position far away from the load layer, so that the transverse modal suppression effect is achieved, and the Q value of the surface acoustic wave device and device is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of surface acoustic wave, in particular to a surface acoustic wave device structure and apparatus. BACKGROUND

[0002] The basic structure of a surface acoustic wave (SAW) device is to make an acoustoelectric transducer on a piezoelectric substrate material, which has the advantages of small size, large bandwidth, low insertion loss, low cost, mass production, etc., and is widely used in mobile communication devices. With the development of communication protocols, the requirements for filters, duplexers and other radio frequency devices are becoming higher and higher, and the optimization design of the acoustoelectric transducer is particularly important for obtaining high-performance SAW devices.

[0003] In recent years, surface acoustic wave devices have been widely used due to their excellent quality factor (Q value), low temperature drift coefficient, large bandwidth, high power and other advantages. However, the existing surface acoustic wave devices will be excited to produce unnecessary transverse mode dispersion (or transverse resonance mode, transverse mode, etc.) during use. The dispersion response caused by these transverse modes will cause fluctuations in the passband, increase the energy loss of the surface acoustic wave device, reduce the Q value of the surface acoustic wave device, and affect the performance.

[0004] Therefore, how to provide a surface acoustic wave device structure and apparatus with transverse mode suppression effect, which can suppress the influence of transverse mode on the performance of the surface acoustic wave device and improve the Q value, has become one of the technical problems to be solved by those skilled in the art. SUMMARY

[0005] The present application aims to at least solve one of the technical problems in the related art.

[0006] To this end, the first purpose of the present application is to provide a surface acoustic wave device with transverse mode suppression effect, which can suppress the influence of transverse mode on the performance of the device, reduce the influence of transverse mode on the Q value of the device, improve the performance of the device, and reduce the production difficulty.

[0007] To achieve the above-mentioned purpose, the first aspect of the present application provides a surface acoustic wave device structure, comprising a substrate, and an IDT electrode and a load layer formed on the substrate; wherein, The IDT electrode comprises two interdigital electrodes arranged oppositely on the substrate; each interdigital electrode comprises a bus bar extending in a first direction, and a plurality of electrode fingers extending from one end of the bus bar in a second direction, and the electrode fingers of different interdigital electrodes are arranged in the first direction in turn. The load layer includes at least a first portion and a second portion located on the IDT. The first portion is located on the busbar and covers the surface of the busbar away from the substrate. The second portion extends from the first portion near the center of the electrode finger along the second direction and partially covers the surface of the electrode finger. In a third direction, the vertical projection of the second portion lies in the vertical projection plane of the electrode finger. The second direction is orthogonal to the first direction, and the third direction is perpendicular to the plane orthogonal to the first and second directions.

[0008] Optionally, the load layer further includes a third portion located on the substrate, and in the third direction, the vertical projection of the third portion is located within the gap between the electrode finger and the busbar in the second direction.

[0009] Optionally, each of the interdigitated electrodes further includes a plurality of dummy fingers, which extend from one side of the busbar along a second direction and are alternately spaced between the electrode fingers in the first direction. In the second direction, the end of each dummy finger is spaced apart from and corresponds one-to-one with the end of an electrode finger.

[0010] Optionally, the second portion extends from the first portion on the side near the center of the electrode finger along the second direction, covering the surface of the spur finger and partially covering the surface of the electrode finger.

[0011] Optionally, the load layer further includes a third portion located on the substrate, and in the third direction, the vertical projection of the third portion lies within the gap between the pseudo-finger and the corresponding electrode finger in the second direction.

[0012] Optionally, in the third direction, the thickness of the third portion is the same as the thickness of the first portion and the second portion, and is less than the thickness of the electrode finger.

[0013] Optionally, in the third direction, the thickness of the third portion is greater than the thickness of the first portion and the second portion, and is the same as the sum of the thicknesses of the second portion and the electrode finger.

[0014] Optionally, the surface acoustic wave device structure further includes a reflective gate electrode, which is formed on the substrate and spaced apart on both sides of the IDT electrode along the first direction.

[0015] Optionally, when the load layer is composed of the first portion, the second portion, and the third portion, it is composed of an insulating material or a dielectric material with dielectric properties; when the load layer is composed of the first portion and the second portion, it is composed of an insulating material or a dielectric material with dielectric properties, or it is composed of a metal or alloy material with high-density conductivity.

[0016] To achieve the above objectives, a second aspect of this application provides a surface acoustic wave (SAW) device, which includes the SAW device structure described in any one of the above claims.

[0017] The surface acoustic wave device structure and apparatus provided in this application have at least the following beneficial effects: This application provides a surface acoustic wave (SAW) device structure and apparatus with transverse mode suppression effect, including a substrate, an interdigitated electrode (IDT), and a load layer. The IDT electrode is formed on the substrate and includes two interdigitated electrodes disposed opposite each other. Each interdigitated electrode includes a busbar and multiple electrodes, with the electrode fingers of different interdigitated electrodes arranged alternately. The load layer is formed on the substrate and includes at least a first portion and a second portion. By setting the first portion on the busbar and setting the second portion to extend from the first portion towards the center of the electrode finger and partially cover the electrode finger, with the vertical projection of the third portion located within the projection plane of the electrode finger, the electrode finger is divided into two regions. This allows the SAW generated by the IDT electrode to be affected by the load layer and form multiple different sound velocity regions within the electrode finger range. Furthermore, the propagation speed of the SAW near the end of the electrode finger is less than the propagation speed at the corresponding position of the electrode finger away from the load layer. In effect, this is equivalent to adding a suppression load at the end of the electrode finger, which can suppress transverse modes and improve the Q value of the SAW device and apparatus.

[0018] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0019] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein: Figure 1 This is a top-view structural diagram of the first surface acoustic wave device structure according to an embodiment of this application.

[0020] Figure 2 According to Figure 1 A schematic diagram of the cross-sectional structure of the first type of surface acoustic wave device, taken from line AA.

[0021] Figure 3This is a top-view structural diagram of a second surface acoustic wave device structure according to an embodiment of this application.

[0022] Figure 4 According to Figure 3 A schematic diagram of the cross-sectional structure of the first type of surface acoustic wave device, taken from the BB line.

[0023] Figure 5 According to Figure 3 A schematic diagram of the cross-sectional structure of the second type of surface acoustic wave device structure taken from the BB line.

[0024] Figure 6 This is a top-view structural diagram of the third surface acoustic wave device structure according to an embodiment of this application.

[0025] Figure 7 According to Figure 6 A schematic diagram of the cross-sectional structure of a surface acoustic wave device, taken from the CC line.

[0026] Figure 8 This is a top-view structural diagram of the fourth surface acoustic wave device structure according to an embodiment of this application.

[0027] Figure 9 According to Figure 8 A schematic cross-sectional view of a surface acoustic wave device structure taken from the DD line.

[0028] Figure 10 This is a top-view structural diagram of the fifth type of surface acoustic wave device structure according to an embodiment of this application.

[0029] Figure 11 According to Figure 10 A schematic diagram of the cross-sectional structure of the first type of surface acoustic wave device structure taken from the EE line.

[0030] Figure 12 According to Figure 10 A schematic diagram of the cross-sectional structure of the second type of surface acoustic wave device structure, taken from the EE line.

[0031] Figure 13 According to Figure 1 A schematic diagram of the cross-sectional structure of the second type of surface acoustic wave device, taken from line AA in the middle.

[0032] Figure 14 According to Figure 1 A schematic diagram of the cross-sectional structure of the third type of surface acoustic wave device structure, taken from line AA.

[0033] Figure 15 A performance diagram of a surface acoustic wave device according to the prior art is shown. Figure 16This is a performance diagram of a surface acoustic wave device according to an embodiment of this application.

[0034] 100 Substrate; 110 High-velocity substrate layer; 120 High-velocity material layer; 130 Low-velocity material layer; 140 Piezoelectric material layer; 200 IDT electrode; 210 Busbar; 220 Electrode finger; 230 Pseudo-finger; 300 Load layer; 310 First section; 320 Second section; 330 Third section; 400 Reflective gate electrode. Detailed Implementation

[0035] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application.

[0036] Surface acoustic wave (SAW) devices are acoustic devices widely used in the radio frequency field. They include SAW resonators or SAW filters, which combine low insertion loss and good suppression performance, while also being small in size. They mainly utilize the piezoelectric effect to convert electrical energy and mechanical energy into each other.

[0037] For conventional SAW devices, surface acoustic waves propagating laterally along the length of the finger strips will form transverse resonant modes on the substrate, i.e., transverse modes appearing in and near the passband. These transverse modes increase device losses, causing significant fluctuations in the Q value and reducing the performance of SAW devices (resonators, filters). Therefore, existing technologies, such as adding suppression loads to the finger strip ends of the electrodes, can achieve some transverse mode suppression. However, this method generally suffers from high processing requirements and costs. Furthermore, directly processing the finger strip ends can also affect the propagation of the dominant mode to some extent, leading to a decrease in the Q value.

[0038] To address the aforementioned issues, this application provides a surface acoustic wave (SAW) device structure and apparatus, comprising a substrate, an integrated digital transducer (IDT) electrode, and a load layer. The load layer is formed on the substrate and includes at least a first portion and a second portion. This application divides the electrode finger into two regions by placing the first portion on the busbar of the IDT electrode and setting the second portion to extend from the first portion towards the center of the electrode finger and partially cover the electrode finger, with the vertical projection of the second portion in the direction of the third direction located within the projection plane of the electrode finger. This allows the SAW generated by the IDT electrode to be influenced by the load layer, forming multiple different sound velocity regions within the electrode finger range. Furthermore, the propagation speed of the SAW near the end of the electrode finger is lower than the propagation speed at the corresponding position away from the load layer. This effectively adds a suppression load to the end of the electrode finger, suppressing transverse modes and improving the Q value of the SAW device and apparatus.

[0039] According to one aspect of this application, a surface acoustic wave device structure with transverse mode suppression effect is provided, such as... Figures 1 to 15 As shown, the device structure includes a substrate 100, an IDT electrode 200 (Interdigital transducer), and a load layer 300 formed on the substrate 100. For ease of description, the propagation direction of the surface acoustic wave is defined as the first direction, i.e., the X direction in the figure; the direction of the extension of the fingers of the IDT electrode 200 is defined as the second direction, i.e., the Y direction in the figure; and the direction of the stack thickness of the surface acoustic wave device structure is defined as the third direction, i.e., the Z direction in the figure. The first and second directions are orthogonal to each other and parallel to the surface of the substrate 100, while the third direction is perpendicular to the plane orthogonal to the first and second directions.

[0040] The IDT electrode 200, as the most basic unit constituting the structure of the surface acoustic wave device, can be composed of a high-density conductive metal or alloy material, including but not limited to one or an alloy of metals such as titanium, chromium, copper, silver, aluminum, platinum, tungsten, and molybdenum. It can be a single-layer metal film or a stacked metal film with multiple metal layers. In this application, the IDT electrode 200 is preferably a stack of titanium and aluminum, with the aluminum film formed on top of the titanium film.

[0041] like Figure 1 and Figure 2 As shown, the IDT electrode 200 is formed on the substrate 100 and includes two interdigitated electrodes disposed opposite to each other. Each interdigitated electrode includes a busbar 210 extending along a first direction and a plurality of electrode fingers 220 extending from one side of the busbar 210 along a second direction. In the first direction, the electrode fingers 220 of different interdigitated electrodes are arranged alternately.

[0042] The load layer 300, as a key functional layer for suppressing transverse modes in the surface acoustic wave (SAW) device structure, can be composed of insulating or dielectric materials with specific dielectric properties, including but not limited to silicon dioxide, aluminum nitride, zinc oxide, silicon nitride, aluminum oxide, or composite dielectric materials. It can be a single-layer dielectric film or a stacked dielectric film with multiple different dielectric layers. Alternatively, the load layer 300 can be composed of high-density conductive metals or alloys, including but not limited to titanium, chromium, copper, silver, aluminum, platinum, tungsten, molybdenum, or metal alloys. It can be a single-layer metal film or a stacked metal film with multiple metal layers. In this application, the load layer 300 is preferably a single-layer silicon dioxide film, or a stack of silicon dioxide and aluminum nitride, with the silicon dioxide film formed on top of the aluminum nitride film.

[0043] The load layer 300 is also formed on the substrate 100, including a first portion 310 and a second portion 320 located on the IDT electrode 200. The first portion 310 is located on the busbar 210 and covers the surface of the busbar 210 away from the substrate 100. The second portion 320 extends from the first portion 310 near the electrode finger 220 along the center of a second direction and partially covers the surface of the electrode finger 220. In the third direction, the vertical projection of the second portion 320 lies within the vertical projection plane of the electrode finger 220.

[0044] Furthermore, a pair of reflective gate electrodes 400 may be provided on the substrate 100 on both sides of the IDT electrode 200 along the first direction, and the pair of reflective gate electrodes 400 are spaced apart on both sides of the IDT electrode 200 along the first direction.

[0045] It is understandable that surface acoustic waves (SAWs) are a typical type of elastic wave. By applying an alternating voltage to the IDT electrode 200, SAW devices can be excited to generate SAWs. When SAWs propagate in a material, they are reflected at the interface of different media (which have different sound propagation speeds). This reflection prevents stray waves from resonating and thus reduces energy loss.

[0046] The propagation speed and impedance of an elastic wave in a medium satisfy the formula Z = ρC, where Z is the acoustic impedance, ρ is the density of the medium, and C is the speed of sound. It can be seen from the formula that the greater the density of the propagation medium, the greater the acoustic impedance, meaning that the elastic wave experiences greater resistance to propagation within the medium.

[0047] This application forms a load layer 300 on a substrate 100, with a first portion 310 of the load layer 300 located on a busbar 210, covering the surface of the busbar 210 away from the substrate 100. A second portion 320 of the load layer 300 extends from the side of the first portion 310 near the electrode finger 220 along a second direction toward the center of the corresponding electrode finger 220, partially covering the surface of the electrode finger 220. Simultaneously, in a third direction, the vertical projection of the second portion 320 lies within the vertical projection plane of the electrode finger 220, thus dividing the electrode finger 220 in the second direction into a first region covered by the second portion 320 and a second region not covered by the second portion 320. This allows the surface acoustic wave excited by the IDT electrode 200 to be influenced by the first portion 310 and the second portion 320 of the load layer 300, resulting in different propagation speeds in the first and second regions of the electrode finger 220, forming multiple different sound velocity zones. This effectively suppresses the transverse modes of the surface acoustic wave device, preventing the excitation of transverse mode resonance.

[0048] Specifically, the area formed by the staggered extension of the electrode fingers 220 of different interdigitated electrodes in the first direction can be defined as the staggered region. The staggered region can be further divided into two first staggered regions and one second staggered region in the second direction, with the second staggered region located between the two first staggered regions. The second staggered region is the area corresponding to the overlapping of any adjacent electrode fingers 220 in the first direction. The first staggered region is located between the second staggered region and the two busbars 210, that is, the area formed by the interval between the ends of the electrode fingers 220 and the busbars 210.

[0049] Since the vertical projection of the second portion 320 in the third direction lies within the vertical projection plane of the electrode finger 220, when the second portion 320 extends along the second direction on the electrode finger 220, its boundary on the side away from the end of the busbar 210 must at least lie on the electrode finger 220 and maintain a predetermined distance from the end of the electrode finger 220. Therefore, when the surface acoustic wave excited by the IDT electrode 200 propagates along the first direction in the first interleaving region, it can be affected by the second portion 320 and exhibit at least two different propagation speeds. Similarly, when the surface acoustic wave excited by the IDT electrode 200 propagates along the first direction in the second interleaving region, it is also affected by the second portion 320 and exhibits at least two different propagation speeds.

[0050] Specifically, because the second portion 320 alters the mass distribution of the electrode fingers 220 on the substrate 100, the second region has a lower density of the surface acoustic wave propagation medium and a smaller acoustic impedance compared to the first region. Consequently, the propagation speed of surface acoustic waves in the second region is greater than that in the first region. Similarly, since the first region overlaps between the first and second interleaved regions, the area where the first and second interleaved regions overlap but not with the first interleaved region can be defined as the first overlapping region. The first overlapping region has a higher density of the surface acoustic wave propagation medium and a larger acoustic impedance compared to both the first and second interleaved regions. Consequently, the propagation speed of surface acoustic waves in the first overlapping region is less than that in both the first and second interleaved regions.

[0051] In other words, by setting the vertical projection of the second portion 320 within the vertical projection plane of the electrode finger 220, this application effectively increases the propagation speed of the surface acoustic wave at the end (first overlap region) of the electrode finger 220 compared to the propagation speed in the second region of the electrode finger 220. This is equivalent to adding a suppression load to the end of the electrode finger 220. Compared to the prior art which uses a thickened (Piston structure) and / or widened (hammerhead structure) metal suppression load at the end of the electrode finger 220, this application not only suppresses transverse modes and improves the Q value of the surface acoustic wave device, but also significantly reduces the fabrication difficulty and cost of the surface acoustic wave device structure.

[0052] In some embodiments, such as Figures 3 to 5 As shown, the load layer 300 also includes a third portion 330 located on the substrate 100, and in the third direction, the vertical projection of the third portion 330 is located in the gap between the electrode finger 220 and the busbar 210 in the second direction.

[0053] Because the vertical projection of the third portion 330 in the third direction is located within the gap between the electrode finger 220 and the busbar 210 in the second direction, the surface acoustic wave generated by the IDT electrode 200, when propagating along the first direction in the first interleaving region, is affected by the third portion 330 and exhibits a different propagation speed than when the third portion 330 is not present. This further adjusts the propagation of the surface acoustic wave in the first interleaving region and improves the transverse mode suppression effect of the surface acoustic wave.

[0054] As an example, such as Figure 4 As shown, in the third direction, the thickness of the third portion 330 is the same as the thickness of the first portion 310 and the second portion 320, and is less than the thickness of the electrode finger 220.

[0055] As an example, such as Figure 5As shown, in the third direction, the thickness of the third portion 330 is greater than the thickness of the first portion 310 and the second portion 320, and is the same as the sum of the thicknesses of the second portion 320 and the electrode finger 220.

[0056] In some embodiments, such as Figure 6 and Figure 7 As shown, each interdigitated electrode also includes a plurality of pseudofinger 230, each pseudofinger 230 being formed in the first interlacing region and extending from one side of the busbar 210 along a second direction. In the second direction, the tip of each electrode finger 220 of one interdigitated electrode should be spaced apart from the tip of each pseudofinger 230 of another interdigitated electrode, and the two should correspond one-to-one.

[0057] Since the pseudo-finger 230 is formed in the first interleaved region, and each pseudo-finger 230 is spaced apart from the end of an electrode finger 220 and corresponds one-to-one, when the surface acoustic wave generated by the IDT electrode 200 propagates in the second interleaved region along the first direction, it can be affected by the region corresponding to the pseudo-finger 230 and have at least two different propagation speeds in the first interleaved region. Moreover, the propagation speed of the surface acoustic wave in the region corresponding to the pseudo-finger 230 is smaller than that in the interval region between the ends of the pseudo-finger 230 and the electrode finger 220, thereby further suppressing the transverse mode of the surface acoustic wave device and improving the Q value of the surface acoustic wave device.

[0058] Furthermore, such as Figure 8 and Figure 9 As shown, the second portion 320 extends from the first portion 310 near the center of the electrode finger 220 along the second direction, covering both the surface of the electrode finger 220 and the surface of the dummy finger 230. This allows the surface acoustic wave generated by the IDT electrode 200 to propagate along the first direction in the first interleaving region, resulting in different propagation speeds in the corresponding area of ​​the dummy finger 230 due to the influence of the second portion 320 covering it. This further adjusts the propagation of the surface acoustic wave in the first interleaving region, improving the transverse mode suppression effect.

[0059] Correspondingly, such as Figures 10 to 12 As shown, when the load layer 300 includes the third portion 330, the third portion 330 is located in the gap region between the pseudo-finger 230 and the end of the electrode finger 220. That is, the vertical projection of the third portion 330 in the third direction is located in the gap between the electrode finger 220 and the busbar 210 in the second direction. Therefore, when the surface acoustic wave generated by the IDT electrode 200 propagates in the first crossover region along the first direction, it can also be affected by the third portion 330, and exhibit a different propagation speed than when the third portion 330 is not present. Thus, the propagation of the surface acoustic wave in the first crossover region is further adjusted, and the transverse mode suppression effect of the surface acoustic wave is improved.

[0060] As an example, such as Figure 11 As shown, in the third direction, the thickness of the third portion 330 is the same as the thickness of the first portion 310 and the second portion 320, and is less than the thickness of the electrode finger 220.

[0061] As an example, such as Figure 12 As shown, in the third direction, the thickness of the third portion 330 is greater than the thickness of the first portion 310 and the second portion 320, and is the same as the sum of the thicknesses of the second portion 320 and the electrode finger 220.

[0062] It should be noted that, in the above examples, when the load layer 300 includes only the first portion 310 and the second portion 320, the load layer 300 may be composed of an insulating material or a dielectric material with specific dielectric properties, or it may be composed of a high-density conductive metal or alloy material. Conversely, when the load layer 300 includes the third portion 330, the load layer 300 may be composed of an insulating material or a dielectric material with specific dielectric properties.

[0063] Furthermore, the aforementioned surface acoustic wave device structure is POI-SAW, and the substrate 100 may include a piezoelectric substrate, which is a laminated substrate containing a piezoelectric material layer 140, such as... Figure 13 and Figure 14 As shown, the IDT electrode 200 is formed on the piezoelectric material layer 140. The stacked substrate can be a stacked substrate in which a low-velocity material layer 130 and a piezoelectric material layer 140 are sequentially stacked on a high-velocity substrate layer 110, or a stacked substrate in which a high-velocity material layer 120, a low-velocity material layer 130 and a piezoelectric material layer 140 are sequentially stacked on a high-velocity substrate layer 110.

[0064] Specifically, the piezoelectric material layer 140 includes, but is not limited to, materials selected from various cuts such as LiTaO3 (lithium tantalate), LiNbO3 (lithium niobate), quartz, zinc oxide (ZnO), and aluminum nitride (AlN). In this embodiment, the piezoelectric material layer 140 preferably uses lithium niobate or lithium tantalate, which have excellent piezoelectric and electromechanical coupling effects and have been widely used in surface acoustic wave device structures.

[0065] The low-velocity material layer 130 is a film layer with a relatively low sound velocity, so that the propagation speed of surface acoustic waves in the low-velocity material layer 130 is lower than that in the piezoelectric material layer 140. The low-velocity material layer 130 includes, but is not limited to, materials such as silicon oxide, glass, silicon oxynitride, tantalum oxide, or materials whose main component is a compound obtained by adding fluorine, carbon, or boron to silicon oxide. In this embodiment, the low-velocity material layer 130 is preferably a silicon oxide film (SiOx), such as a SiO2 film.

[0066] The high-velocity acoustic material layer 120 is a film layer with a relatively high sound velocity, so that the propagation speed of surface acoustic waves in the high-velocity acoustic material layer 120 is higher than that in the piezoelectric material layer 140. The high-velocity acoustic material layer 120 includes, but is not limited to, a dielectric material using one of the following as its main component: silicon nitride, aluminum nitride, zinc oxide, silicon oxynitride, sapphire, and aluminum oxide. In this embodiment, the high-velocity acoustic material layer 120 is an aluminum nitride film (AlN).

[0067] The hypersonic substrate 110 serves as a supporting substrate for the multilayer substrate and may include, but is not limited to, a variety of materials such as alumina, lithium tantalate, lithium niobate, piezoelectric materials like quartz, bauxite, sapphire, magnesium oxide, silicon nitride, aluminum nitride, silicon carbide, zirconium oxide, cordierite, mullite, block talc, forsterite, etc., as well as various ceramics, diamond, glass, semiconductors like gallium nitride, or resins. In this embodiment, the hypersonic substrate 110 is preferably a silicon substrate.

[0068] According to a second aspect of this application, a surface acoustic wave (SAW) device is also provided, which includes the SAW device structure described in any of the above embodiments.

[0069] To further illustrate the transverse mode suppression effect of the surface acoustic wave (SAW) device provided in this application, the SAW device can be applied to a specific scenario, such as in a resonator or filter, and the performance graph of the resonator or filter can be viewed. If a large number of parasitic resonance peaks appear in the graph, it indicates that the resonator or filter exhibits strong transverse mode ripples and severe passband clutter, and using the SAW device will lead to a deterioration in overall performance.

[0070] As an example, the performance of existing surface acoustic wave (SAW) devices and the SAW device of this application can be compared when applied to resonators. The comparison results are as follows: Figure 15 and Figure 16 As shown, where, Figure 15 The figure shows the performance of a resonator using a conventional surface wave device structure that lacks transverse mode suppression. Figure 16 The performance diagram shows the resonator using the surface wave device structure described in this application. Based on... Figure 15 and Figure 16 The comparison shows that Figure 16 The intermediate admittance curves are all smoother, and compared to Figure 15 Intermediate admittance curve, Figure 16 The number of parasitic resonance peaks in the admittance curve is almost invisible, which indicates that the surface wave device structure provided in this application can effectively suppress transverse modes in the resonator, further improve the Q value of the resonator or filter, and significantly improve the performance of the resonator or filter.

[0071] Furthermore, the surface acoustic wave device with transverse mode suppression effect according to any of the above embodiments disclosed herein can also be provided in or integrated into any processor-based device. Examples include, but are not limited to, set-top boxes, entertainment units, navigation devices, communication devices, fixed location data units, mobile orientation data units, global positioning system (GPS) devices, mobile phones, cellular phones, smartphones, session initiation protocol (SIP) phones, tablet computers, phablets, servers, computers, portable computers, mobile computing devices, wearable computing devices (e.g., smartwatches, health or fitness trackers, glasses, etc.), desktop computers, personal digital assistants (PDAs), monitors, computer monitors, televisions, tuners, radios, satellite radios, music players, digital music players, portable music players, digital video players, video players, digital video disc (DVD) players, portable digital video players, automobiles, vehicle components, avionics systems, drones, and multirotor aircraft.

[0072] In summary, this application provides a surface acoustic wave device structure and apparatus with transverse mode suppression effect, including a substrate 100, an IDT electrode 200, and a load layer 300. The IDT electrode 200 is formed on the substrate 100 and includes two interdigitated electrodes disposed opposite to each other. Each interdigitated electrode includes a bus bar 210 and multiple electrodes. The electrode fingers 220 of different interdigitated electrodes are arranged alternately. The load layer 300 is formed on the substrate 100 and includes at least a first portion 310 and a second portion 320. This application divides the electrode finger 220 into two regions by setting the first portion 310 on the busbar 210 and setting the second portion 320 to extend from the first portion 310 toward the center of the electrode finger 220 and partially cover the electrode finger 220, with the vertical projection of the third direction located in the projection plane of the electrode finger 220. This allows the surface acoustic wave generated by the IDT electrode 200 to be affected by the load layer 300 and form multiple different sound velocity regions within the electrode finger 220. Moreover, the propagation speed of the surface acoustic wave near the end of the electrode finger 220 is less than the propagation speed of the electrode finger 220 away from the corresponding position of the electrode finger 220. In effect, this is equivalent to adding a suppression load to the end of the finger bar of the electrode finger 220, which can suppress the transverse mode and improve the Q value of the surface acoustic wave device and apparatus.

[0073] In the foregoing descriptions of the embodiments, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this application. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of those different embodiments or examples.

[0074] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

Claims

1. A surface acoustic wave device structure, characterized in that, Includes a substrate, and an IDT electrode and a load layer formed on the substrate; wherein, The IDT electrode includes two interdigitated electrodes disposed opposite each other on the substrate; each interdigitated electrode includes a bus bar extending along a first direction and a plurality of electrode fingers extending from one end of the bus bar along a second direction, and the electrode fingers of different interdigitated electrodes are arranged alternately in the first direction. The load layer includes at least a first portion and a second portion located on the IDT. The first portion is located on the busbar and covers the surface of the busbar away from the substrate. The second portion extends from the first portion near the center of the electrode finger along the second direction and partially covers the surface of the electrode finger. In a third direction, the vertical projection of the second portion lies in the vertical projection plane of the electrode finger. The second direction is orthogonal to the first direction, and the third direction is perpendicular to the plane orthogonal to the first and second directions.

2. The surface acoustic wave device structure according to claim 1, characterized in that, The load layer further includes a third portion located on the substrate, and in the third direction, the vertical projection of the third portion is located within the gap between the electrode finger and the busbar in the second direction.

3. The surface acoustic wave device structure according to claim 1, characterized in that, Each of the interdigitated electrodes also includes a plurality of dummy fingers, which extend from one side of the busbar along a second direction and are alternately spaced between the electrode fingers in the first direction. In the second direction, the end of each dummy finger is spaced apart from and corresponds one-to-one with the end of an electrode finger.

4. The surface acoustic wave device structure according to claim 3, characterized in that, The second portion extends from the first portion on the side near the center of the electrode finger along the second direction, covering the surface of the spur finger and partially covering the surface of the electrode finger.

5. The surface acoustic wave device structure according to claim 4, characterized in that, The load layer further includes a third portion located on the substrate, and in the third direction, the vertical projection of the third portion lies within the gap between the pseudo-finger and the corresponding electrode finger in the second direction.

6. The surface acoustic wave device structure according to claim 2 or 5, characterized in that, In the third direction, the thickness of the third portion is the same as the thickness of the first portion and the second portion, and is less than the thickness of the electrode finger.

7. The surface acoustic wave device structure according to claim 2 or 5, characterized in that, In the third direction, the thickness of the third portion is greater than the thickness of the first portion and the second portion, and is the same as the sum of the thicknesses of the second portion and the electrode finger.

8. The surface acoustic wave device structure according to claim 1, characterized in that, The surface acoustic wave device structure further includes a reflective gate electrode, which is formed on the substrate and spaced apart on both sides of the IDT electrode along the first direction.

9. The surface acoustic wave device structure according to claim 2, characterized in that, When the load layer is composed of the first portion, the second portion, and the third portion, it is composed of an insulating material or a dielectric material with dielectric properties; when the load layer is composed of the first portion and the second portion, it is composed of an insulating material or a dielectric material with dielectric properties, or it is composed of a metal or alloy material with high-density conductivity.

10. A surface acoustic wave device, characterized in that, The surface acoustic wave device includes the surface acoustic wave device structure as described in any one of claims 1 to 9.

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