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, the IDT electrode is formed on the substrate and comprises two interdigital electrodes which are oppositely arranged, each interdigital electrode comprises a bus bar and a plurality of electrodes, and electrode fingers of different interdigital electrodes are arranged at intervals in a staggered manner. At least one groove is formed in the electrode finger, and the vertical projection of the groove is located in the vertical projection plane of the electrode finger, so that the surface acoustic wave formed by excitation of the IDT electrode can be influenced by the groove to form a plurality of different sound velocity regions in the range of the electrode finger; and the propagation velocity of the surface acoustic wave at the position close to the end part of the electrode finger is smaller than the propagation velocity of the surface acoustic wave at the position corresponding to the groove of the electrode finger, so that the effect is equivalent to increase of a suppression load at the tail end of the finger strip of the electrode finger, the effect of suppressing the transverse mode can be achieved, and the processing technology requirement and the technology cost of the surface acoustic wave device structure are also reduced.

Description

Technical Field

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

[0002] The basic structure of the surface acoustic wave (SAW) device is to make an acoustic-electric transducer on a piezoelectric substrate material. It has the advantages of small size, large bandwidth, low insertion loss, low cost, and mass production, and is widely used in mobile communication devices. With the development of communication protocols, the requirements for RF devices such as filters and duplexers are getting higher and higher. The optimized design of the acoustic-electric 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, etc. However, existing surface acoustic wave devices will be excited during use and produce unnecessary transverse modal spurious (or transverse resonant mode, transverse mode, etc.). The spurious response generated 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 a transverse mode suppression effect, which can suppress the influence of the transverse mode on the performance of the surface acoustic wave device and improve the Q value, has become one of the technical problems that people in this field need to solve urgently. Summary of the invention

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

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

[0007] To achieve the above-mentioned purpose, the first embodiment of the present application proposes a surface acoustic wave device structure, including:

[0008] substrate;

[0009] The IDT electrode comprises two interdigitated electrodes arranged opposite to each other on the substrate; each of the interdigitated electrodes comprises 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 alternately arranged in sequence in the first direction;

[0010] Each of the electrode fingers is further provided with at least one groove extending along the second direction, and the vertical projection of the groove in the third direction is located within 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 orthogonal plane of the first direction and the second direction.

[0011] Optionally, the electrode finger includes a first surface and a second surface opposite to each other in the third direction, the second surface is in contact with the substrate, and the groove extends from the first surface to a side of the second surface by a preset depth.

[0012] Optionally, a preset depth of the groove extending from the first surface to one side of the second surface is not greater than a thickness of the electrode finger.

[0013] Optionally, preset depths of the grooves corresponding to different electrode fingers extending from the first surface to one side of the second surface are different.

[0014] Optionally, the groove extends along the second direction until a preset distance is maintained between the end of the electrode finger extending along the second direction.

[0015] Optionally, when a plurality of grooves are provided on the electrode finger, the plurality of grooves are sequentially spaced apart along the second direction.

[0016] Optionally, a central axis of each electrode finger along the second direction overlaps with a central axis of a corresponding groove along the second direction.

[0017] Optionally, each of the interdigitated electrodes further includes a plurality of dummy fingers, which extend from one side of the bus bar along the second direction and are alternately arranged in sequence between the electrode fingers in the first direction, and in the second direction, the end of each of the dummy fingers is spaced apart from and corresponds one-to-one to the end of an electrode finger.

[0018] Optionally, the surface acoustic wave device structure further includes a reflection gate electrode, which is formed on the substrate and is formed at intervals on both sides of the IDT electrode along the first direction.

[0019] Optionally, each of the reflective gate electrodes includes a plurality of connecting fingers extending along the second direction, each of the connecting fingers is provided with at least one first groove extending along the second direction, and a vertical projection of the first groove in the third direction is located within a vertical projection plane corresponding to the connecting finger.

[0020] To achieve the above-mentioned purpose, a second aspect of the present application provides a surface acoustic wave device, which includes any one of the surface acoustic wave device structures described above.

[0021] The surface acoustic wave device structure and apparatus provided by the present application have at least the following beneficial effects:

[0022] The present application provides a surface acoustic wave device structure and device, including a substrate and an IDT electrode, wherein the IDT electrode is formed on the substrate and includes two interdigitated electrodes arranged opposite to each other, each interdigitated electrode includes a bus bar and a plurality of electrodes, and the electrode fingers of different interdigitated electrodes are arranged in a staggered manner. The present application forms at least one groove on the electrode finger, and the vertical projection of the groove is located within the vertical projection plane of the electrode finger, so that the surface acoustic wave formed by the excitation of the IDT electrode can be affected by the groove and form a plurality of different sound velocity zones within the electrode finger range, and the propagation speed of the surface acoustic wave at the position close to the end of the electrode finger is less than the propagation speed at the position corresponding to the groove of the electrode finger, which is equivalent to adding a suppression load at the end of the electrode finger, which can not only suppress the lateral mode and improve the Q value of the surface acoustic wave device, but also greatly reduce the processing technology requirements of the surface acoustic wave device structure and reduce the process cost.

[0023] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0025] Figure 1 It is a schematic cross-sectional structure diagram of a first surface acoustic wave device structure according to an embodiment of the present application.

[0026] Figure 2 Based on Figure 1 Schematic diagram of the longitudinal cross-section structure of the first surface acoustic wave device structure taken along line AA.

[0027] Figure 3 It is a schematic cross-sectional structure diagram of a second surface acoustic wave device structure according to an embodiment of the present application.

[0028] Figure 4 Based on Figure 3 Schematic diagram of the longitudinal cross-section structure of a surface acoustic wave device structure taken along line BB.

[0029] Figure 5 Schematic diagram of the cross-sectional structure of a third surface acoustic wave device structure according to an embodiment of the present application.

[0030] Figure 6 Schematic diagram of the cross-sectional structure of a fourth surface acoustic wave device structure according to an embodiment of the present application.

[0031] Figure 7 It is a schematic cross-sectional structure diagram of a fifth surface acoustic wave device structure according to an embodiment of the present application.

[0032] Figure 8 Based on Figure 7 A schematic diagram of the longitudinal cross-section structure of a surface acoustic wave device structure taken along line A'A'.

[0033] Fig. 9 It is a schematic cross-sectional structure diagram of a sixth surface acoustic wave device structure according to an embodiment of the present application.

[0034] Fig.10 Based on Fig. 9 A schematic diagram of the longitudinal cross-section structure of a surface acoustic wave device structure taken along line B'B'.

[0035] Fig.11 Schematic diagram of the cross-sectional structure of a seventh surface acoustic wave device structure according to an embodiment of the present application.

[0036] Fig.12 Based on Figure 1 Schematic diagram of the longitudinal cross-section structure of the second surface acoustic wave device structure taken along line AA.

[0037] Fig.13 Based on Figure 1 Schematic diagram of the longitudinal cross-section structure of the third surface acoustic wave device structure taken along line AA.

[0038] Fig.14 Based on Figure 1 Schematic diagram of the longitudinal cross-section structure of the fourth surface acoustic wave device structure taken along line AA.

[0039] Fig.15 FIG. 4 is a graph showing the performance of a surface acoustic wave device according to the prior art.

[0040] Fig.16 FIG. 4 is a performance diagram of a surface acoustic wave device according to an embodiment of the present application.

[0041] 100 substrate; 110 high acoustic velocity substrate layer; 120 high acoustic velocity material layer; 130 low acoustic velocity material layer; 140 piezoelectric material layer; 200 IDT electrode; 210 bus bar; 220 electrode finger; 221 groove; 230 dummy finger; 300 reflective gate electrode; 310 connecting finger; 311 first groove; 400 temperature compensation layer; 500 passivation layer. DETAILED DESCRIPTION

[0042] The embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present application, and should not be construed as limiting the present application.

[0043] A surface acoustic wave (SAW) device is an acoustic device widely used in the radio frequency field, including a surface acoustic wave resonator or a surface acoustic wave filter. It combines low insertion loss and good suppression performance with a small size and mainly uses the piezoelectric effect to convert electrical energy and mechanical energy into each other.

[0044] For conventional SAW devices, surface acoustic waves propagating laterally along the length direction of the finger will form a transverse resonant mode on the substrate, that is, a transverse mode that appears in and near the passband. This transverse mode will increase the device loss, cause the Q value to fluctuate greatly, and reduce the performance of the SAW device (resonator, filter). Therefore, the prior art suppresses the transverse mode by increasing the mass load at the end of the finger, such as providing a thickened (piston structure) and / or widened (hammerhead structure) metal end at the end of the finger, or tilting the electrode finger to reduce the speed of sound in this area. However, although the method of adding a suppression load to the finger end of the electrode finger can achieve a certain transverse mode suppression effect, this method is sensitive to the size and weight of the suppression load, and has high requirements for the processing technology, increasing the process cost. At the same time, direct processing of the finger end will also affect the propagation of the main mode to a certain extent, resulting in a reduction in the Q value.

[0045] Based on the above problems, the present application provides a surface acoustic wave device structure and apparatus, by forming at least one groove on the electrode finger, using the groove to change the mass distribution of the electrode finger in its extension direction, so that the surface acoustic wave formed by the IDT electrode excitation can be affected by the groove and form multiple different sound speed zones within the electrode finger range, thereby changing the propagation speed of the surface acoustic wave on the substrate. The present application places the vertical projection of the groove within the vertical projection plane of the electrode finger, so that the propagation speed of the surface acoustic wave at the position close to the end of the electrode finger (outside the groove) is less than the propagation speed at the corresponding position of the groove of the electrode finger. In effect, it is equivalent to adding a suppression load at the end of the electrode finger, which can not only suppress the lateral mode and improve the Q value of the surface acoustic wave device, but also greatly reduce the processing technology requirements of the surface acoustic wave device structure and reduce the process cost.

[0046] According to one aspect of the present application, a surface acoustic wave device structure having a lateral mode suppression effect is provided, such as Figure 1 to Figure 14As shown, the device structure includes a substrate 100 and an IDT electrode 200 (interdigital transducer). For ease of description, the propagation direction of the surface acoustic wave is set as the first direction, that is, the X direction in the figure, the direction in which the fingers of the IDT electrode 200 extend is set as the second direction, that is, the Y direction in the figure, and the direction of the stacking thickness of the surface acoustic wave device structure is set as the third direction, that is, the Z direction in the figure. The first direction and the second direction are orthogonal to each other and parallel to the surface of the substrate 100, and the third direction is perpendicular to the orthogonal plane of the first direction and the second direction.

[0047] 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 of titanium, chromium, copper, silver, aluminum, platinum, tungsten, molybdenum and other metals or their metal alloys, and can be a single-layer metal film or a laminated metal film with multiple metal layers laminated. In the present application, the IDT electrode 200 preferably uses a laminate of metal titanium and aluminum, and the metal aluminum film is formed on the metal titanium film.

[0048] like Figure 1 and Figure 2 As shown, the IDT electrode 200 is formed on the substrate 100, and includes two interdigitated electrodes arranged opposite to each other, each interdigitated electrode includes a bus bar 210 extending along a first direction, and a plurality of electrode fingers 220 extending from one side of the bus bar 210 along a second direction, each electrode finger 220 is also provided with at least one groove 221 extending along the second direction, and the vertical projection of the groove 221 in the third direction is located within the vertical projection plane of the electrode finger 220, and in the first direction, the electrode fingers 220 of different interdigitated electrodes are arranged in an alternating manner.

[0049] It is understandable that the surface acoustic wave is a typical elastic wave, and the surface acoustic wave device can be excited to form a surface acoustic wave by applying an AC voltage to the IDT electrode 200. When the surface acoustic wave propagates in a substance, it will reflect the surface acoustic wave that is not parallel to the interface when it encounters the interface of different media (with different sound propagation speeds), thus avoiding the formation of resonance of stray waves, thereby playing a role in reducing energy loss.

[0050] According to the relationship between the propagation speed of elastic waves in the medium and impedance, Z = ρC, where Z is the acoustic impedance, ρ is the medium density, and C is the speed of sound. From the formula, it can be seen that the greater the density of the propagation medium, the greater the acoustic impedance, that is, the greater the resistance encountered by elastic waves when propagating in the medium.

[0051] The present application provides at least one groove 221 extending along the second direction on each electrode finger 220 so as to change the mass distribution of the electrode finger 220 on the substrate 100 by using the groove 221, and the vertical projection of the groove 221 in the third direction is located within the vertical projection plane of the electrode finger 220, so that the surface acoustic wave excited by the IDT electrode 200 can be affected by the groove 221, and the area corresponding to the groove 221 and the area corresponding to the non-groove 221 of the electrode finger 220 show different propagation speeds, and form a plurality of different sound speed zones, thereby effectively suppressing the transverse mode of the surface acoustic wave device and avoiding the excitation of transverse mode resonance.

[0052] Since at least one groove 221 extending along the second direction is provided on the electrode finger 220, the density of the surface acoustic wave propagation medium in the area corresponding to the groove 221 is reduced, and the acoustic impedance is reduced, so that the propagation speed of the surface acoustic wave in the area corresponding to the groove 221 is greater than the propagation speed of the non-groove corresponding area. In the present application, by setting the vertical projection of the groove 221 in the vertical projection plane of the electrode finger 220, the propagation speed of the surface acoustic wave at the end (non-groove corresponding area) of the electrode finger 220 is less than the propagation speed of the groove 221 corresponding area of ​​the electrode finger 220, which is equivalent to adding a suppression load at the end of the electrode finger 220. Compared with the prior art that sets a thickened (piston structure) and / or widened (hammerhead structure) metal suppression load at the end of the electrode finger 220, the present application can not only suppress the lateral mode and improve the Q value of the surface acoustic wave device, but also greatly reduce the processing difficulty and process cost of the surface acoustic wave device structure.

[0053] Specifically, the region formed by the staggered extension of the electrode fingers 220 of different interdigitated electrodes in the first direction can be set as the staggered region, and the staggered region can be divided into two first staggered regions and one second staggered region in the second direction according to the electrode fingers 220, and the second staggered region is located between the two first staggered regions. Among them, the second staggered region is the region corresponding to the staggered overlap of any adjacent electrode fingers 220 in the first direction, and the first staggered region is located between the second staggered region and the two bus bars 210, that is, the region corresponding to the interval between the end of the electrode finger 220 and the bus bar 210.

[0054] Since the vertical projection of the groove 221 in the third direction is located within the vertical projection plane of the electrode finger 220, when the groove 221 extends along the second direction on the electrode finger 220, the boundary of the groove 221 close to the end of the electrode finger 220 needs to maintain a preset 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 interlaced area, it can be affected by the corresponding area of ​​the groove 221 and has at least two different propagation speeds in the second interlaced area, namely, the first sound speed area between the groove 221 and the end of the electrode finger 220 and the second sound speed area corresponding to the position of the groove 221, and the propagation speed of the surface acoustic wave in the second sound speed area is greater than that in the first sound speed area, thereby effectively suppressing the transverse mode of the surface acoustic wave device and avoiding the excitation of transverse mode resonance.

[0055] like Figure 3 to Figure 6 As shown, a plurality of grooves 221 may be provided on one electrode finger 220. Figure 3 and Figure 4 As shown, the interval between any two adjacent grooves 221 of the plurality of grooves 221 in the second direction will form a first sound velocity zone corresponding to the second staggered area, thereby further adjusting the sound velocity regional distribution of the surface acoustic wave in the second staggered area, thereby improving the transverse mode suppression effect of the surface acoustic wave.

[0056] Since the specific position, number and size of the grooves 221 on the electrode fingers 220 directly affect the mass distribution of the electrode fingers 220, and further affect the velocity distribution of the surface acoustic wave in the second interlaced zone. Therefore, in order to further improve the transverse mode suppression effect of the surface acoustic wave device structure, the present application can also be adjusted based on the setting position, number and size of the grooves 221 on the electrode fingers 220 and any combination of the above conditions to finely adjust the propagation speed of the surface acoustic wave in the second sound velocity zone, so as to suppress the transverse mode without affecting the main acoustic mode, and also reflect various stray waves to avoid additional energy dissipation, thereby improving the performance of the surface acoustic wave device. Therefore, the present application does not specifically limit the number and size of the grooves 221 extending along the second direction on the electrode fingers 220. That is to say, the number of grooves 221 set on each electrode finger 220 can be one groove 221 extending along the second direction, or multiple grooves 221 spaced from each other in the second direction, and the sizes of the multiple grooves 221 can be the same or different.

[0057] The dimensions of the groove 221 on the electrode finger 220 may specifically include an extension width along the first direction, an extension length along the second direction, and an extension depth along the third direction. The extension width of the groove 221 in the first direction should not be greater than the width of the electrode finger 220, and the extension length in the second direction should not be greater than the length of the second interlaced region, so as to ensure that the vertical projection of the groove 221 in the third direction can be located within the vertical projection plane of the electrode finger 220. At the same time, the extension depth of the groove 221 in the third direction should not be greater than the thickness of the electrode finger 220, so as to ensure that the surface of the substrate 100 is not damaged during the formation of the groove 221.

[0058] As an example, the electrode finger 220 may include a first surface and a second surface opposite to each other in the third direction, the second surface contacts the substrate 100, and the groove 221 extends from the first surface of the electrode finger 220 to one side of the second surface until a preset depth is met.

[0059] Since the specific extension depth of the groove 221 in the third direction can also change the mass distribution of the electrode finger 220 on the substrate 100, the different depths of the groove 221 also have a direct impact on the propagation speed of the surface acoustic wave. By controlling the depth of the groove 221 in the third direction and making it meet the preset depth, the propagation speed of the surface acoustic wave in the first sound speed zone can be effectively controlled.

[0060] In some embodiments, Figure 7 to Figure 10 As shown, each interdigitated electrode further includes a plurality of dummy fingers 230, each dummy finger 230 being formed in the first interdigitated region and extending from one side of the bus bar 210 along the second direction. In the second direction, the end of each electrode finger 220 of one interdigitated electrode should be spaced from the end of each dummy finger 230 of another interdigitated electrode, and the two should correspond to each other one by one.

[0061] Since the dummy fingers 230 are formed correspondingly in the first interlaced region, and each dummy finger 230 is spaced apart and corresponds one to one with the end of an electrode finger 220, when the surface acoustic wave excited by the IDT electrode 200 propagates along the first direction in the second interlaced region, it can be affected by the corresponding area of ​​the dummy finger 230 and has at least two different propagation speeds in the second interlaced region, namely, the third sound velocity region between the end of the dummy finger 230 and the end of the electrode finger 220 and the fourth sound velocity region corresponding to the position of the dummy finger 230, and the propagation speed of the surface acoustic wave in the fourth sound velocity region is greater than that in the third sound velocity region, thereby further suppressing the transverse mode of the surface acoustic wave device and improving the Q value of the surface acoustic wave device.

[0062] In addition, if Fig.11As shown, a pair of reflective gate electrodes 300 are further provided on the substrate 100 on both sides of the IDT electrode 200 along the first direction, and the pair of reflective gate electrodes 300 are formed at intervals along the first direction on both sides of the IDT electrode 200. Each reflective gate electrode 300 includes a plurality of connecting fingers 310 extending along the second direction, and each connecting finger 310 is provided with at least one first groove 311 extending along the second direction, and the vertical projection of the first groove 311 in the third direction is located within the vertical projection plane corresponding to the connecting finger 310.

[0063] It should be noted that the first groove 311 formed on the connecting finger 310 and the groove 221 on the electrode finger 220 may be the same or different, and this application does not make any specific limitation on this.

[0064] The above-mentioned surface acoustic wave device structure can be a common surface acoustic wave device structure, i.e., STD-SAW (Standard Surface Acoustic Wave), or a surface acoustic wave device structure based on a POI (Piezoelectric on Insulator, insulator-based piezoelectric material) substrate 100, i.e., POI-SAW, or a temperature-compensated surface acoustic wave device structure, i.e., TC-SAW (Temperature Compensation Surface Acoustic Wave, TC-SAW). The present application does not specifically limit the specific type of the surface acoustic wave device structure.

[0065] As an example, when the surface acoustic wave device structure is a POI-SAW, the substrate 100 may include a piezoelectric substrate, which is a laminated substrate including a piezoelectric material layer 140, such as Fig.12 and Fig.13 As shown, the IDT electrode 200 is formed on the piezoelectric material layer 140. The stacked substrate may be a stacked substrate in which a low acoustic velocity material layer 130 and a piezoelectric material layer 140 are stacked in sequence on a high acoustic velocity substrate layer 110, or a stacked substrate in which a high acoustic velocity material layer 120, a low acoustic velocity material layer 130 and a piezoelectric material layer 140 are stacked in sequence on a high acoustic velocity substrate layer 110.

[0066] Specifically, the piezoelectric material layer 140 includes, but is not limited to, one of the materials of LiTaO3 (lithium tantalate), LiNbO3 (lithium niobate), quartz, zinc oxide (ZnO), aluminum nitride (AlN) and the like in various cuts. In this embodiment, the piezoelectric material layer 140 preferably uses lithium niobate or lithium tantalate, which has advantages such as excellent piezoelectric effect and electromechanical coupling effect, and has been widely used in surface acoustic wave device structures.

[0067] The low acoustic velocity material layer 130 is a film layer with a relatively low acoustic velocity, so that the propagation speed of the surface acoustic wave in the low acoustic velocity material layer 130 is lower than the propagation speed of the surface acoustic wave in the piezoelectric material layer 140. The low acoustic velocity material layer 130 includes, but is not limited to, one of silicon oxide, glass, silicon oxynitride, tantalum oxide, etc., or a material with a compound obtained by adding fluorine, carbon or boron to silicon oxide as the main component. In this embodiment, the low acoustic velocity material layer 130 preferably uses a silicon oxide film (SiOx), such as a SiO2 film.

[0068] The high acoustic velocity material layer 120 is a film layer with a relatively high acoustic velocity, so that the propagation speed of the surface acoustic wave in the high acoustic velocity material layer 120 is higher than the propagation speed of the surface acoustic wave in the piezoelectric material layer 140. The high acoustic velocity material layer 120 includes, but is not limited to, a medium using one of silicon nitride, aluminum nitride, zinc oxide, silicon oxynitride, sapphire, aluminum oxide, etc. as a main component. In this embodiment, the high acoustic velocity material layer 120 is an aluminum nitride film (AlN).

[0069] The high acoustic velocity substrate layer 110 is used as a supporting base of the piezoelectric substrate 100, including but not limited to using one of alumina, lithium tantalate, lithium niobate, piezoelectrics such as quartz, alumina, sapphire, magnesium oxide, silicon nitride, aluminum nitride, silicon carbide, zirconium oxide, cordierite, mullite, steatite, forsterite and other ceramics, diamond, glass and other dielectrics, gallium nitride and other semiconductors or resins, etc. In this embodiment, the high acoustic velocity substrate layer 110 preferably uses a silicon substrate.

[0070] As an example, when the surface acoustic wave device structure is TC-SAW, the substrate 100 may be a piezoelectric material layer 140, such as Fig.14 As shown, the IDT electrode 200 is formed on the piezoelectric material layer 140. At the same time, after the IDT electrode 200 is formed on the piezoelectric material layer 140, a temperature compensation layer 400 is formed on the piezoelectric material layer 140 to completely cover the IDT electrode 200, and a passivation layer 500 is formed on the temperature compensation layer 400 to cover the upper surface of the temperature compensation layer 400.

[0071] The temperature compensation layer 400 is composed of a material that can provide a positive temperature coefficient, including but not limited to a combination of one or more of silicon dioxide, germanium dioxide, and silicon oxyfluoride. Since ordinary SAW is easily affected by temperature changes, a TC-SAW with a temperature compensation function can be formed by coating a layer of temperature compensation material with a positive frequency temperature coefficient, thereby improving the temperature drift phenomenon.

[0072] The passivation layer 500 is made of a material with stable properties, including but not limited to silicon nitride, and is used to protect and isolate the surface of the temperature compensation layer 400 .

[0073] According to a second aspect of the present application, a surface acoustic wave device is also provided, which includes the surface acoustic wave device structure described in any of the above embodiments.

[0074] In order to further illustrate the transverse mode suppression effect of the surface acoustic wave device provided in the present application, the surface acoustic wave device in the present application can be applied to a specific scenario, for example, the surface acoustic wave device is applied to a resonator or a filter, and the performance graph of the resonator or the filter is viewed. If there are many parasitic resonance peaks in the graph, it can be indicated that the resonator or the filter has strong transverse mode ripples, the passband clutter is serious, and the use of the surface acoustic wave device will lead to the deterioration of the overall performance.

[0075] As an example, the existing surface acoustic wave device and the surface acoustic wave device of the present application can be applied to the resonator for performance comparison. The comparison results are as follows: Fig.15 and Fig.16 As shown, Fig.15 This is a performance diagram of a resonator using a conventional surface wave device structure that has no transverse mode suppression effect. Fig.16 is a performance diagram of a resonator to which the surface wave device structure of the present application is applied. Fig.15 and Fig.16 The comparison shows that Fig.16 The admittance curves are smoother and Fig.15 Medium admittance curve, Fig.16 The number of parasitic resonance peaks in the medium admittance curve is almost invisible, which means that the surface wave device structure provided in the present application can effectively suppress the transverse mode in the resonator, further improve the Q value of the resonator or filter, and significantly improve the performance of the resonator or filter.

[0076] In addition, 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 position data units, mobile position data units, global positioning system (GPS) devices, mobile phones, cellular phones, smart phones, session initiation protocol (SIP) phones, tablet computers, tablet phones, servers, computers, portable computers, mobile computing devices, wearable computing devices (e.g., smart watches, 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.

[0077] In summary, the present application provides a surface acoustic wave device structure and apparatus with a lateral mode suppression effect, including a substrate 100 and an IDT electrode 200. The IDT electrode 200 is formed on the substrate 100 and includes two interdigitated electrodes arranged opposite to each other. Each interdigitated electrode includes a bus bar 210 and a plurality of electrodes. The electrode fingers 220 of different interdigitated electrodes are arranged in an alternating manner. In the present application, at least one groove 221 is formed on the electrode finger 220, and the vertical projection of the groove 221 is located within the vertical projection plane of the electrode finger 220, so that the surface acoustic wave formed by the excitation of the IDT electrode 200 can be affected by the groove 221 and form multiple different sound speed zones within the range of the electrode finger 220, and the propagation speed of the surface acoustic wave near the end position of the electrode finger 220 is less than the propagation speed at the corresponding position of the groove 221 of the electrode finger 220. In effect, it is equivalent to adding a suppression load to the end of the electrode finger 220, which can not only suppress the lateral mode and improve the Q value of the surface acoustic wave device, but also greatly reduce the processing technology requirements of the surface acoustic wave device structure and reduce the process cost.

[0078] In the description of the foregoing embodiments, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. Moreover, the described specific features, structures, materials or characteristics may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, unless they contradict each other.

[0079] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of this application, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

Claims

1. A surface acoustic wave device structure, characterized in that: include: substrate; The IDT electrode comprises two interdigitated electrodes arranged opposite to each other on the substrate; each of the interdigitated electrodes comprises 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 alternately arranged in sequence in the first direction; Each of the electrode fingers is further provided with at least one groove extending along the second direction, and the vertical projection of the groove in the third direction is located within 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 orthogonal plane of the first direction and the second direction.

2. The surface acoustic wave device structure according to claim 1, characterized in that: The electrode finger includes a first surface and a second surface opposite to each other in the third direction, the second surface is in contact with the substrate, and the groove extends from the first surface to a side of the second surface by a preset depth.

3. The surface acoustic wave device structure according to claim 2, characterized in that: A preset depth of the groove extending from the first surface to one side of the second surface is not greater than a thickness of the electrode finger.

4. The surface acoustic wave device structure according to claim 2, characterized in that: The preset depths of the grooves correspondingly arranged on different electrode fingers extending from the first surface to one side of the second surface are different.

5. The surface acoustic wave device structure according to claim 2, characterized in that: The groove extends along the second direction until a preset distance is maintained between the end of the electrode finger extending along the second direction.

6. The surface acoustic wave device structure according to claim 5, characterized in that: When a plurality of grooves are provided on the electrode finger, the plurality of grooves are sequentially spaced apart along the second direction.

7. The surface acoustic wave device structure according to claim 2, characterized in that: The central axis of each electrode finger along the second direction overlaps with the central axis of the corresponding groove along the second direction.

8. The surface acoustic wave device structure according to claim 2, characterized in that: Each of the interdigitated electrodes also includes a plurality of dummy fingers, which extend from one side of the bus bar along the second direction and are alternately arranged in sequence between the first direction and the electrode fingers. In the second direction, the end of each of the dummy fingers is spaced apart from and corresponds one-to-one to the end of an electrode finger.

9. The surface acoustic wave device structure according to claim 2, characterized in that: The surface acoustic wave device structure further includes a reflection gate electrode, which is formed on the substrate and spaced apart on both sides of the IDT electrode along the first direction.

10. The surface acoustic wave device structure according to claim 9, characterized in that: Each of the reflective gate electrodes includes a plurality of connecting fingers extending along the second direction, each of the connecting fingers is provided with at least one first groove extending along the second direction, and a vertical projection of the first groove in the third direction is located within a vertical projection plane corresponding to the connecting finger.

11. A surface acoustic wave device, characterized in that: The surface acoustic wave device comprises the surface acoustic wave device structure according to any one of claims 1 to 10.

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