Bulk acoustic wave resonator, filter, and electronic device having a tungsten electrode

Abstract

The present application relates to a bulk acoustic wave resonator, comprising: a substrate; an acoustic mirror; a bottom electrode; a top electrode; and a piezoelectric layer disposed between the bottom electrode and the top electrode, wherein: the piezoelectric layer is a doped piezoelectric layer; and the top electrode and / or the bottom electrode is a tungsten electrode containing metallic tungsten. The top electrode and / or the bottom electrode is a single-layer electrode made of metallic tungsten or a single-layer electrode made of a tungsten alloy. Alternatively, the top electrode and / or the bottom electrode is a stacked electrode comprising at least two electrode layers of different materials stacked together, the at least two electrode layers comprising at least one tungsten electrode layer, the tungsten electrode layer being an electrode layer made of metallic tungsten or an electrode layer made of a tungsten alloy. The present application also relates to a filter having the above resonator and an electronic device having the filter or the resonator.

Description

Technical Field

[0001] Embodiments of the present invention relate to the field of semiconductors, and in particular, to a bulk acoustic wave resonator, a filter having the resonator, and an electronic device having the resonator or the filter. Background Art

[0002] Electronic components, as fundamental elements of electronic devices, have been widely used in mobile phones, automobiles, and household appliances. Furthermore, technologies poised to revolutionize the world, such as artificial intelligence, the Internet of Things, and 5G communications, still rely on electronic components as their foundation.

[0003] Electronic devices exhibit distinct characteristics and advantages depending on their operating principles. Devices utilizing the piezoelectric effect (or inverse piezoelectric effect) are a crucial category among all electronic devices, and they have a wide range of applications. Film Bulk Acoustic Resonator (FBAR), also known as bulk acoustic wave resonator (BAW), as a key member of the piezoelectric device family, is playing a vital role in the communications field. FBAR filters, in particular, are gaining a growing market share in the RF filter field. FBARs offer excellent properties such as small size, high resonant frequency, high quality factor, high power handling, and excellent roll-off. They are gradually replacing traditional surface acoustic wave (SAW) and ceramic filters, playing a significant role in wireless communications and RF applications. Their high sensitivity also has applications in sensing fields such as biology, physics, and medicine.

[0004] The cross-sectional diagram of a conventional thin film bulk acoustic resonator is shown in Figure 2. Figure 1 As shown, in Figure 1 For example, the bottom electrode 30 and the top electrode 50 are made of molybdenum, and the piezoelectric layer 40 is made of aluminum nitride. The thicknesses of the bottom electrode 30 and the top electrode 50 are equal, t, and the thickness of the piezoelectric layer 40 is d. The thickness ratio t / d of the single-layer electrode to the piezoelectric layer will affect the effective electromechanical coupling coefficient of the resonator, and thus the bandwidth of the resonator (the larger the effective electromechanical coupling coefficient, the larger the bandwidth). In the design of the thin film bulk acoustic wave resonator, the impedance needs to be matched to 50 ohms. At the same frequency and bandwidth, the thinner the piezoelectric layer thickness, the smaller the area A of the effective region can be, thereby increasing the number of resonators integrated on a single wafer, which can save manufacturing costs.

[0005] The usual method to reduce the thickness of the piezoelectric layer is to use scandium-doped aluminum nitride as the piezoelectric layer to increase its electromechanical coupling coefficient. When the same bandwidth is required, a larger ratio t / d of the thickness of the single-layer electrode to the piezoelectric layer can be taken to achieve the purpose of thinning the thickness of the piezoelectric layer. Matching 50 ohms can reduce the resonator area A.

[0006] However, the above method has a problem that the power capacity of the resonator is reduced due to the reduction of the area of the effective region at the same power density. SUMMARY

[0007] In order to reduce the area of the effective region of the resonator and ensure the power capacity of the resonator, for example, in order to solve the problem of the reduction of the power capacity of the resonator due to the reduction of the area of the effective region after the introduction of scandium-doped aluminum nitride as the piezoelectric layer, the present application is proposed.

[0008] According to an aspect of an embodiment of the present application, a bulk acoustic wave resonator is provided, comprising:

[0009] a substrate;

[0010] an acoustic mirror;

[0011] a bottom electrode;

[0012] a top electrode; and

[0013] a piezoelectric layer disposed between the bottom electrode and the top electrode,

[0014] wherein:

[0015] the piezoelectric layer is a doped piezoelectric layer; and

[0016] the top electrode and / or the bottom electrode is a tungsten electrode containing metallic tungsten.

[0017] Optionally, the top electrode and / or the bottom electrode is a single-layer electrode made of metallic tungsten or a single-layer electrode made of a tungsten alloy.

[0018] Alternatively, the top electrode and / or the bottom electrode is a laminated electrode, the laminated electrode comprising at least two electrode layers of different materials stacked together, the at least two electrode layers comprising at least one tungsten electrode layer, the tungsten electrode layer being an electrode layer made of metallic tungsten or an electrode layer made of a tungsten alloy.

[0019] Embodiments of the present application also relate to a filter comprising the bulk acoustic wave resonator described above.

[0020] Embodiments of the present application also relate to an electronic device comprising the filter described above or the resonator described above. BRIEF DESCRIPTION OF DRAWINGS

[0021] The following description and drawings can better help understand these and other features and advantages of the various embodiments disclosed of the present application, in which the same reference signs refer to the same components throughout the drawings, in which:

[0022] Figure 1 is a schematic cross-sectional view of a conventional thin-film bulk acoustic wave resonator;

[0023] Figure 2 Exemplary shows the relationship between the ratio of the thickness of the single-layer electrode and the thickness of the piezoelectric layer and the electromechanical coupling coefficient of the resonator in the case where the thickness of the top electrode and the bottom electrode is the same, wherein three cases are shown respectively, i.e., the piezoelectric layer is aluminum nitride and the electrodes are both molybdenum, the piezoelectric layer is scandium-doped aluminum nitride and the electrodes are both molybdenum, and the piezoelectric layer is scandium-doped aluminum nitride and the electrodes are both tungsten;

[0024] Figures 3-12 Cross-sectional schematic diagrams of the bulk acoustic wave resonator of different embodiments of the present application are shown respectively. DETAILED DESCRIPTION

[0025] The technical solutions of the present application are further specifically described below by way of examples in conjunction with the accompanying drawings. In the description, identical or similar reference numerals indicate identical or similar components. The following description of the embodiments of the present application with reference to the accompanying drawings is intended to explain the general inventive concept of the present application and should not be construed as a limitation of the present application.

[0026] As known by those skilled in the art, the area of the effective region of the resonator will be smaller if a doped piezoelectric layer is used instead of a piezoelectric layer under the same electromechanical coupling coefficient and frequency, and the power capacity of the resonator will be smaller under the same power density if the area of the effective region of the resonator is smaller.

[0027] Moreover, as known by those skilled in the art, the area of the effective region of the resonator will be smaller if the molybdenum electrode of the resonator is replaced by a tungsten electrode under the same electromechanical coupling coefficient and frequency, which is not conducive to maintaining a larger power capacity.

[0028] In addition, as known by those skilled in the art, the thin-film resistivity of metallic tungsten at room temperature is 20-30 micro-ohm per centimeter, and the thin-film resistivity of metallic molybdenum at room temperature is about 10 micro-ohm per centimeter. It can be seen that the thin-film resistivity of metallic tungsten at room temperature is much greater than the thin-film resistivity of metallic molybdenum at room temperature. Therefore, it is generally believed that the resistance of the tungsten electrode with tungsten as the electrode is greater than the resistance of the molybdenum electrode with molybdenum as the electrode during the operation of the resonator, so that the heat generated by the current flowing through the resistance of the tungsten electrode is greater than that of the molybdenum electrode. In this case, replacing the molybdenum electrode of the resonator with a tungsten electrode will directly lead to an increase in the heat dissipation of the electrode of the resonator during operation, which is not conducive to maintaining a larger power capacity under the condition that the area of the effective region of the resonator is constant. Therefore, those skilled in the art will not think of replacing the molybdenum electrode of the resonator with a tungsten electrode based on maintaining a larger power capacity.

[0029] Based on the above, for the resonator using molybdenum electrode and doped piezoelectric layer (which already has a smaller effective area based on the doping), the common practice of those skilled in the art is to try to avoid replacing the molybdenum electrode in the resonator using molybdenum electrode and doped piezoelectric layer with a tungsten electrode, because using a tungsten electrode will further reduce the area of the effective area and is not conducive to maintaining good power capacity.

[0030] However, the inventors have found that if the molybdenum electrode in the resonator using molybdenum electrode and doped piezoelectric layer is replaced with a tungsten electrode, the power capacity of the resonator can be ensured while reducing the area of the effective area of the resonator.

[0031] Based on the above, the present application proposes a technical solution in which the doped piezoelectric layer (which can reduce the area of the effective area of the resonator) is combined with the tungsten electrode (which can reduce the area of the effective area of the resonator) in the bulk acoustic wave resonator.

[0032] The following refers to the accompanying drawings Figures 2-12 The technical solution of the present application is specifically described. In the present application, the reference signs are simply explained as follows:

[0033] 110, 210, 310: substrate, which can be made of single crystal silicon, quartz, gallium arsenide or sapphire, etc.

[0034] 120, 220, 320: acoustic mirror, which is located on the upper surface of the substrate 110 or embedded in the substrate. In the present application, the acoustic mirror is composed of a cavity embedded in the substrate, but the acoustic mirror can also be a Bragg reflection layer and other equivalent forms.

[0035] 130, 230, 240, 330, 340, 350: single-layer bottom electrode or one bottom electrode layer in the bottom electrode stack, which can be deposited on the upper surface of the acoustic mirror and cover the acoustic mirror. The edge of the bottom electrode 130 can be chamfered, and the chamfer is aligned with the edge of the effective area of the resonator. In addition, the edge of the bottom electrode 130 can also be stepped, vertical or other similar structures. The material of the bottom electrode can be: gold (Au), tungsten (W), molybdenum (Mo), platinum (Pt), ruthenium (Ru), iridium (Ir), titanium tungsten (TiW), aluminum (Al), titanium (Ti), osmium (Os), magnesium (Mg), gold (Au), tungsten (W), molybdenum (Mo), platinum (Pt), ruthenium (Ru), iridium (Ir), germanium (Ge), copper (Cu), aluminum (Al), chromium (Cr), arsenic-doped gold, and similar metals, as well as alloys of the above metals, etc.

[0036] 140, 250, 360: Piezoelectric film layer or piezoelectric layer, which can be selected from materials such as aluminum nitride (AlN), zinc oxide (ZnO), lead zirconate titanate (PZT), lithium niobate (LiNbO3), quartz (Quartz), potassium niobate (KNbO3) or lithium tantalate (LiTaO3) including rare earth element doping materials with a certain atomic ratio, and doping elements such as scandium (Sc), yttrium (Y), magnesium (Mg), titanium (Ti), lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), lutetium (Lu), etc.

[0037] 150, 260, 270, 370, 380, 390: A single-layer top electrode or a top electrode layer in a top electrode stack, the material of which can be: gold (Au), tungsten (W), molybdenum (Mo), platinum (Pt), ruthenium (Ru), iridium (Ir), titanium tungsten (TiW), aluminum (Al), titanium (Ti), osmium (Os), magnesium (Mg), gold (Au), tungsten (W), molybdenum (Mo), platinum (Pt), ruthenium (Ru), iridium (Ir), germanium (Ge), copper (Cu), aluminum (Al), chromium (Cr), arsenic-doped gold and other similar metals, as well as alloys of the above metals. The material of the top electrode can be the same as or different from that of the bottom electrode. Figure 2 In FIG, no passivation layer is provided above the top electrode, but as can be understood, a passivation layer may also be provided.

[0038] 160: Passivation layer, the passivation layer material includes but is not limited to polysilicon SiO2, Si3N4, AlN, etc.

[0039] 170: Raised structure. The raised structure is made of the same material as the top electrode 130, the bottom electrode 150, or the piezoelectric layer 140. The raised structure is located at the edge of the active area and can reduce the acoustic impedance of the active area. In one embodiment of the present invention, the raised structure is made of tungsten.

[0040] The schematic cross-sectional view of the bulk acoustic wave resonator according to the present invention is also as shown in FIG. Figure 1 As shown. In a specific example, the bottom electrode 30 and top electrode 50 of the resonator are made of molybdenum, and the piezoelectric layer 40 is made of scandium-doped aluminum nitride. The thicknesses of the bottom electrode 30 and top electrode 50 are equal, t, and the thickness of the piezoelectric layer 40 is d. The thickness ratio (t / d) of the single-layer electrode to the piezoelectric layer affects the effective electromechanical coupling coefficient of the resonator, and thus the bandwidth of the resonator (a larger effective electromechanical coupling coefficient indicates a larger bandwidth).

[0041] Figure 2Exemplary shows the relationship between the thickness ratio of the single-layer electrode and the piezoelectric layer and the electromechanical coupling coefficient of the resonator when the thickness of the top electrode and the bottom electrode is the same, wherein the piezoelectric layer is aluminum nitride and the electrodes are both molybdenum, the piezoelectric layer is scandium-doped aluminum nitride and the electrodes are both molybdenum, and the piezoelectric layer is scandium-doped aluminum nitride and the electrodes are both tungsten.

[0042] As shown in Figure 2 Exemplary shows the relationship between the thickness ratio of the single-layer electrode and the piezoelectric layer and the electromechanical coupling coefficient of the resonator when the thickness of the top electrode and the bottom electrode is the same, wherein the piezoelectric layer is aluminum nitride and the electrodes are both molybdenum, the piezoelectric layer is scandium-doped aluminum nitride and the electrodes are both molybdenum, and the piezoelectric layer is scandium-doped aluminum nitride and the electrodes are both tungsten. 2 The abscissa is the thickness ratio t / d of the single-layer electrode and the piezoelectric layer, and the ordinate is the effective electromechanical coupling coefficient (Kt eff) of the resonator. The solid line represents the effective electromechanical coupling coefficient when the bottom electrode and the top electrode are molybdenum and the piezoelectric layer is aluminum nitride; the dotted line represents the effective electromechanical coupling coefficient when the bottom electrode and the top electrode are molybdenum and the piezoelectric layer is 3% scandium-doped aluminum nitride, and the effective electromechanical coupling coefficient curve is overall improved; and the dot-dashed line represents the effective electromechanical coupling coefficient when the bottom electrode and the top electrode are tungsten and the piezoelectric layer is 3% scandium-doped aluminum nitride, and the effective electromechanical coupling coefficient curve is further improved overall. The conventional bulk acoustic wave resonator uses molybdenum as the electrode, and when the piezoelectric layer is scandium-doped aluminum nitride, the thickness ratio t / d of the electrode and the piezoelectric layer is increased at the same frequency compared to the case where the piezoelectric layer is aluminum nitride, the electrode thickness is thickened, the piezoelectric layer thickness is thinned, the area A required for matching to 50 ohms is smaller, and the area A of the effective region can be reduced to increase the number of resonators, thereby reducing the manufacturing cost. However, reducing the area A will make the power capacity of the resonator worse.

[0043] In the present application, tungsten electrodes are used instead of molybdenum electrodes. On the one hand, the thermal conductivity coefficient of the tungsten electrode (1.73) is greater than that of the molybdenum electrode (1.38), the thermal conductivity of the tungsten electrode is better, and the power density that the resonator can withstand is greater, and the power capacity can be higher. On the other hand, the tungsten electrode can further improve the effective electromechanical coupling coefficient, and at the same effective electromechanical coupling coefficient, the thickness ratio t / d of the electrode and the piezoelectric layer can be greater. Compared to the molybdenum electrode, the increase in the thickness of the tungsten electrode can reduce the resistance of the thin-film electrode, reduce the heat generated by the electrode resistance, and because the electrode material has better thermal conductivity than the piezoelectric layer material, the power density that the resonator can withstand is greater, and the power capacity can be higher.

[0044] Therefore, in the present application, tungsten electrodes are used in resonators with scandium-doped aluminum nitride piezoelectric layers, which can reduce the area A of the effective region of the resonator while ensuring the power capacity of the resonator. Scandium-doped aluminum nitride as the piezoelectric layer and tungsten as the electrode material can not only reduce the area of the resonator, but also increase the number of resonators integrated on a single wafer, and also ensure the power capacity of the resonator, so that the resonator is not damaged at high power.

[0045] The following refers to Figures 3-12Different embodiments of the present invention are illustrated.

[0046] like Figure 3 As shown, in one embodiment of the present invention, the bottom electrode 130 and the top electrode 150 are tungsten electrodes with the same thickness (t1=t2), and the piezoelectric layer 140 is aluminum nitride or other piezoelectric materials with different doping concentrations.

[0047] In an optional embodiment, Figure 3 In the structure shown, the bottom electrode 130 and the top electrode 150 are tungsten electrodes, but with different thicknesses (t1>t2 or t1 <t2),压电层140为掺杂浓度不同的氮化铝或 其他压电材料。

[0048] In an optional embodiment, Figure 3 In the structure shown, the bottom electrode 130 is a tungsten electrode, the top electrode 150 is a molybdenum electrode or other electrode materials, and the thickness of the top electrode and the bottom electrode are the same or different (t1=t2 or t1>t2 or t1 <t2),压电层140为掺杂浓度不同的氮化铝或其他压电材料。

[0049] In an optional embodiment, Figure 3 In the structure shown, the bottom electrode 130 is a molybdenum electrode or other electrode material, and the top electrode 150 is a tungsten electrode, and the thicknesses are the same or different (t1=t2 or t1>t2 or t1 <t2), 压电层140为掺杂浓度不同的氮化铝或其他压电材料。

[0050] Figure 4 The structure shown is Figure 3 Similar, except that Figure 4 In the embodiment, a passivation layer 160 is added on the top electrode 150.

[0051] Figure 5 The structure shown is Figure 3 Similar, except that Figure 5 In the embodiment, a protruding structure 170 is added on the top electrode 150 .

[0052] Figure 6 The structure shown is Figure 5 Similar, except that Figure 6 In the embodiment, a protrusion structure 170 and a passivation layer 160 are added on the top electrode 150 .

[0053] Figures 3-6 In the structure shown, the top electrode or the bottom electrode is a single-layer electrode structure, but the present invention is not limited thereto. The electrode may also be a stacked structure, in which case one electrode layer in the stacked electrode may be a tungsten electrode layer. Figures 7-12 The following is an exemplary description of a resonator embodiment of a stacked electrode:

[0054] Figure 7 In the embodiment shown in FIG. 2, the top electrode is composed of a laminated structure of the first top electrode 260 and the second top electrode 270, and the bottom electrode is composed of a laminated structure of the first bottom electrode 240 and the second bottom electrode 230, wherein 260 and 240 are tungsten electrodes, and 270 and 230 can be layers of other electrode materials.

[0055] Figure 8 The structure shown in FIG. 2 is similar to that shown in FIG. 1, except that Figure 7 the top electrode in FIG. 2 has only 260, wherein 260 and 240 are tungsten electrodes, and 230 can be a layer of other electrode material. Figure 8

[0056] Figure 9 The structure shown in FIG. 3 is similar to that shown in FIG. 2, except that Figure 7 the bottom electrode in FIG. 3 has only 240, wherein 370 and 350 are tungsten electrodes, and 380 and 390 can be layers of other electrode materials, and 390 can be a tungsten electrode. Figure 9

[0057] Figure 10 In the embodiment shown in FIG. 4, the top electrode is composed of a laminated structure of the first top electrode 370, the second top electrode 380, and the third top electrode 390, and the bottom electrode is composed of a laminated structure of the first bottom electrode 350, the second bottom electrode 340, and the third bottom electrode 330, wherein 370 and 350 are tungsten electrodes, and 330, 340, 380, and 390 can be layers of other electrode materials, and 330 and 390 can still be tungsten electrodes.

[0058] Figure 11 The structure shown in FIG. 4 is similar to that shown in FIG. 3, except that Figure 10 the top electrode in FIG. 4 has only 370, wherein 370 and 350 are tungsten electrodes, and 330 and 340 can be layers of other electrode materials, and 330 can be a tungsten electrode. Figure 11

[0059] The structure shown in FIG. 5 is similar to that shown in FIG. 4, except that Figure 12 the bottom electrode in FIG. 5 has only 240, wherein 370 and 350 are tungsten electrodes, and 380 and 390 can be layers of other electrode materials, and 390 can be a tungsten electrode. Figure 10 Figure 12 In the embodiment shown in FIG. 6, the upper and lower sides of the piezoelectric layer are both provided with tungsten electrode layers, but the present application is not limited thereto, and for example, a tungsten electrode layer can be provided on only one side of the piezoelectric layer.

[0060] Figures 7-12

[0061] ​​​​​In the above-described embodiments of the present application, the tungsten electrode or the tungsten electrode layer is formed of metallic tungsten, but the present application is not limited thereto, and the tungsten electrode or the tungsten electrode layer can also be formed of a tungsten alloy (i.e., an alloy containing metallic tungsten), which is within the scope of the present application.

[0062] It should be noted that in the present application, each numerical range, except for the case where it is explicitly stated that the end point value is not included, can be the median value of the numerical range in addition to the end point value, which is within the scope of the present application.

[0063] In the present application, up and down are relative to the bottom surface of the substrate of the resonator, and for a component, the side close to the bottom surface is the lower side, and the side away from the bottom surface is the upper side.

[0064] In the present application, inner and outer are relative to the center of the active area of the resonator (i.e., the active area center) in the lateral direction or the radial direction, and for a component, the side or end close to the active area center is the inner side or end, and the side or end away from the active area center is the outer side or end. For a reference position, the inner side of the position means between the position and the active area center in the lateral direction or the radial direction, and the outer side of the position means further away from the active area center than the position in the lateral direction or the radial direction.

[0065] As can be understood by those skilled in the art, the bulk acoustic wave resonator according to the present application can be used to form a filter or an electronic device. The electronic device herein includes, but is not limited to, intermediate products such as radio frequency front-ends, filter amplification modules, and terminal products such as mobile phones, WIFI, and drones.

[0066] Based on the above, the present application proposes the following technical solutions:

[0067] 1. A bulk acoustic wave resonator, comprising:

[0068] a substrate;

[0069] an acoustic mirror;

[0070] a bottom electrode;

[0071] a top electrode; and

[0072] a piezoelectric layer disposed between the bottom electrode and the top electrode,

[0073] wherein:

[0074] the piezoelectric layer is a doped piezoelectric layer; and

[0075] the top electrode and / or the bottom electrode is a tungsten electrode containing metallic tungsten.

[0076] 2. The resonator according to claim 1, wherein:

[0077] The top and / or bottom electrode is a single-layer electrode made of metallic tungsten or a single-layer electrode made of a tungsten alloy.

[0078] 3. The resonator according to claim 2, wherein:

[0079] The top and bottom electrodes are both tungsten electrodes; and

[0080] The ratio of the single-layer thickness of the top or bottom electrode to the thickness of the doped piezoelectric layer is in the range of 0.1 to 1.

[0081] 4. The resonator according to claim 2, wherein:

[0082] The top and bottom electrodes are both tungsten electrodes.

[0083] The non-electrode-attached end of the bottom electrode is located outside the boundary of the acoustic mirror in the horizontal direction and forms thermal contact with the substrate.

[0084] 5. The resonator according to claim 2, wherein:

[0085] One of the top and bottom electrodes is a tungsten electrode and the other is a non-tungsten electrode, and the thickness of the tungsten electrode is different from the thickness of the non-tungsten electrode; or

[0086] One of the top and bottom electrodes is a tungsten electrode and the other is a non-tungsten electrode, and the thickness of the tungsten electrode is equal to the thickness of the non-tungsten electrode.

[0087] 6. The resonator according to claim 1, wherein:

[0088] The top and / or bottom electrode is a laminated electrode, the laminated electrode including at least two electrode layers of different materials stacked one on another, the at least two electrode layers including at least one tungsten electrode layer, the tungsten electrode layer being an electrode layer made of metallic tungsten or an electrode layer made of a tungsten alloy.

[0089] 7. The resonator according to claim 6, wherein:

[0090] The electrode layer of the laminated electrode adjacent to the piezoelectric layer is a first electrode layer, the first electrode layer being a tungsten electrode layer.

[0091] 8. The resonator according to claim 7, wherein:

[0092] The top and bottom electrodes are both laminated electrodes.

[0093] 9. The resonator according to claim 8, wherein:

[0094] The non-electrode connecting end of the bottom electrode is in thermal contact with the substrate outside the boundary of the acoustic mirror in the horizontal direction.

[0095] 10. The resonator of 7, wherein:

[0096] One of the top and bottom electrodes is a stacked electrode and the other is a non- stacked electrode.

[0097] 11. The resonator of any one of 1-10, wherein:

[0098] The piezoelectric layer is scandium-doped aluminum nitride.

[0099] 12. The resonator of any one of 1-10, wherein:

[0100] The resonator further includes a protruding structure disposed along the active area, the protruding structure being of tungsten.

[0101] 13. A filter comprising the bulk acoustic wave resonator of any one of 1-12.

[0102] 14. An electronic device comprising the filter of 13 or the resonator of any one of 1-12.

[0103] While embodiments of the application have been shown and described, it is to be understood that the embodiments described are merely exemplary of the principles and application of the present application. Modifications can be made by those skilled in the art, particularly in light of the teachings of the specification, without departing from the spirit of the present application, and the present application is thus not limited to the examples contained herein but includes all such modifications within its scope and equivalences to the following claims.

Claims

1. A bulk acoustic wave resonator, comprising: substrate; Acoustic mirror; bottom electrode; Top electrode; and A piezoelectric layer is provided between the bottom electrode and the top electrode, wherein: The piezoelectric layer is a doped piezoelectric layer; and The top electrode and / or the bottom electrode is a tungsten electrode containing metallic tungsten; The top electrode and / or the bottom electrode is a single-layer electrode, and the ratio of the single-layer thickness of the top electrode or the bottom electrode to the thickness of the doped piezoelectric layer is in the range of 0.1-1; or The top electrode and / or the bottom electrode is a stacked electrode, which includes at least two stacked electrode layers of different materials. The electrode layer adjacent to the piezoelectric layer of the stacked electrode is a first electrode layer, which is a tungsten electrode layer.

2. The resonator according to claim 1, wherein: The top electrode and / or the bottom electrode is a single-layer electrode made of metal tungsten or a single-layer electrode made of a tungsten alloy.

3. The resonator according to claim 2, wherein: The top electrode and the bottom electrode are both tungsten electrodes.

4. The resonator according to claim 2, wherein: The top electrode and the bottom electrode are both tungsten electrodes; The non-electrode connection ends of the bottom electrode are all located outside the boundary of the acoustic mirror in the horizontal direction and form thermal contact with the substrate.

5. The resonator according to claim 2, wherein: One of the top electrode and the bottom electrode is a tungsten electrode, and the other is a non-tungsten electrode, and the thickness of the tungsten electrode is different from the thickness of the non-tungsten electrode; or One of the top electrode and the bottom electrode is a tungsten electrode, and the other is a non-tungsten electrode. The thickness of the tungsten electrode is equal to that of the non-tungsten electrode.

6. The resonator according to claim 1, wherein: The top electrode and the bottom electrode are both stacked electrodes.

7. The resonator according to claim 6, wherein: The non-electrode connection ends of the bottom electrode are all located outside the boundary of the acoustic mirror in the horizontal direction and form thermal contact with the substrate.

8. The resonator of claim 1 , wherein: One of the top electrode and the bottom electrode is a stacked electrode, and the other is a non-stacked electrode.

9. The resonator according to any one of claims 1 to 8, wherein: The piezoelectric layer is scandium-doped aluminum nitride.

10. The resonator according to any one of claims 1 to 8, wherein: The resonator further includes a protruding structure arranged along the effective area, and the material of the protruding structure is tungsten.

11. A filter comprising the bulk acoustic wave resonator according to any one of claims 1 to 10.

12. An electronic device comprising the filter according to claim 11 or the resonator according to any one of claims 1 to 10.

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