WO2022111415A1 - Bulk acoustic resonator having tungsten electrode, filter, and electronic device - Google Patents

Bulk acoustic resonator having tungsten electrode, filter, and electronic device Download PDF

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Publication number
WO2022111415A1
WO2022111415A1 PCT/CN2021/132122 CN2021132122W WO2022111415A1 WO 2022111415 A1 WO2022111415 A1 WO 2022111415A1 CN 2021132122 W CN2021132122 W CN 2021132122W WO 2022111415 A1 WO2022111415 A1 WO 2022111415A1
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electrode
tungsten
resonator
layer
electrodes
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PCT/CN2021/132122
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French (fr)
Chinese (zh)
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庞慰
张孟伦
宁远
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诺思(天津)微系统有限责任公司
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    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
    • H03H9/15—Constructional features of resonators consisting of piezoelectric or electrostrictive material
    • H03H9/17—Constructional features of resonators consisting of piezoelectric or electrostrictive material having a single resonator
    • H03H9/171—Constructional features of resonators consisting of piezoelectric or electrostrictive material having a single resonator implemented with thin-film techniques, i.e. of the film bulk acoustic resonator [FBAR] type
    • H03H9/172—Means for mounting on a substrate, i.e. means constituting the material interface confining the waves to a volume
    • H03H9/173—Air-gaps
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
    • H03H9/02—Details
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
    • H03H9/02—Details
    • H03H9/02007—Details of bulk acoustic wave devices
    • H03H9/02015—Characteristics of piezoelectric layers, e.g. cutting angles
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
    • H03H9/15—Constructional features of resonators consisting of piezoelectric or electrostrictive material
    • H03H9/17—Constructional features of resonators consisting of piezoelectric or electrostrictive material having a single resonator

Definitions

  • 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.
  • FBAR Film Bulk Acoustic Resonator
  • BAW Bulk Acoustic Resonator
  • FBAR filter in radio frequency filter
  • SAW surface acoustic wave
  • FIG. 1 A schematic cross-sectional view of a conventional thin film bulk acoustic resonator is shown in FIG. 1 .
  • the bottom electrode 30 and the top electrode 50 are made of molybdenum
  • the piezoelectric layer 40 is made of aluminum nitride.
  • the thicknesses of the bottom electrode 30 and the top electrode 50 are equal to t, and the thickness of the piezoelectric layer 40 is d.
  • the thickness ratio t/d of the thickness of the monolayer electrode and the piezoelectric layer affects the effective electromechanical coupling coefficient of the resonator, which in turn affects the bandwidth of the resonator (the larger the effective electromechanical coupling coefficient, the larger the bandwidth).
  • the impedance needs to be matched to 50 ohms.
  • the thinner the piezoelectric layer is the smaller the area A of the effective area can be, so that the number of resonators integrated on a single wafer can be reduced. The more, the manufacturing cost can be saved.
  • the usual method for reducing the thickness of the piezoelectric layer is to use scandium-doped aluminum nitride as the piezoelectric layer to increase the electromechanical coupling coefficient.
  • a larger ratio of the thickness of the single-layer electrode to the piezoelectric layer, t/ d, so as to achieve the purpose of reducing the thickness of the piezoelectric layer, matching 50 ohms can reduce the area A of the resonator.
  • the present invention is proposed.
  • a bulk acoustic wave resonator comprising:
  • a piezoelectric layer arranged between the bottom electrode and the top electrode
  • the piezoelectric layer is a doped piezoelectric layer
  • the top electrode and/or the bottom electrode are tungsten electrodes containing metal tungsten.
  • the top electrode and/or the bottom electrode is a single-layer electrode made of metal tungsten or a single-layer electrode made of tungsten alloy.
  • the top electrode and/or the bottom electrode are stacked electrodes, the stacked electrodes include at least two stacked electrode layers of different materials, and the at least two electrode layers include at least one layer of tungsten electrodes
  • the tungsten electrode layer is an electrode layer made of metal tungsten or an electrode layer made of tungsten alloy.
  • Embodiments of the present invention also relate to a filter comprising the above-mentioned bulk acoustic wave resonator.
  • Embodiments of the present invention also relate to an electronic device comprising the above-mentioned filter or the above-mentioned resonator.
  • FIG. 1 is a schematic cross-sectional view of a conventional thin-film bulk acoustic resonator
  • FIG. 2 exemplarily shows the relationship between the ratio of the thickness of the single-layer electrode to the thickness of the piezoelectric layer and the electromechanical coupling coefficient of the resonator in the case where the thicknesses of the top and bottom electrodes are the same, wherein the respective The three cases are that the piezoelectric layer is aluminum nitride, the electrodes are all molybdenum, the piezoelectric layer is scandium-doped aluminum nitride, the electrodes are all molybdenum, the piezoelectric layer is scandium-doped aluminum nitride, and the electrodes are all tungsten;
  • 3-12 respectively illustrate schematic cross-sectional views of bulk acoustic wave resonators according to different embodiments of the present invention.
  • the area of the effective area of the resonator will become smaller, while the area of the effective area of the resonator will become smaller.
  • the smaller the area the smaller the power capacity of the resonator at the same power density.
  • the sheet resistivity of metal tungsten at room temperature is 20-30 microohms per centimeter, and the sheet resistivity of metal molybdenum at room temperature is about 10 microohms per centimeter. It can be seen that at room temperature , the film resistivity of metal tungsten is much greater than that of metal molybdenum at room temperature. Therefore, it is generally believed that the resistance of the tungsten electrode with tungsten as the electrode is greater than that of the molybdenum electrode with molybdenum as the electrode during the working process of the resonator, so that the heat generated by the tungsten electrode due to the current flowing through the resistance is larger than that of the molybdenum electrode.
  • replacing the molybdenum electrode of the resonator with a tungsten electrode will directly lead to an increase in the heat release of the electrode of the resonator during operation. large power capacity. Therefore, those skilled in the art would not think of replacing the molybdenum electrodes of the resonators with tungsten electrodes based on maintaining a large power capacity.
  • the inventors found that if the molybdenum electrodes in the resonators using molybdenum electrodes and doped piezoelectric layers are replaced with tungsten electrodes, the area of the effective region of the resonator can be reduced, and the power capacity of the resonator can be ensured.
  • the present invention proposes a technical solution of combining a doped piezoelectric layer (which can reduce the area of the effective area of the resonator) and a tungsten electrode (which can reduce the area of the effective area of the resonator) in a bulk acoustic wave resonator .
  • the optional material is single crystal silicon, quartz, gallium arsenide or sapphire, etc.
  • acoustic mirrors which are located on the upper surface of the substrate 110 or embedded in the interior of the substrate.
  • the acoustic mirror is formed by a cavity embedded in the substrate, but the acoustic mirror can also be a Bragg reflection layer and other Equivalent form.
  • a single-layer bottom electrode or a bottom electrode layer in a bottom electrode stack which may be deposited on the upper surface of the acoustic mirror and cover the acoustic mirror.
  • the edge of the bottom electrode 130 can be etched into a bevel, and the bevel is aligned with the edge of the effective area of the resonator, and 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 other similar metals, as well as alloys of the above metals.
  • piezoelectric thin film layer or piezoelectric layer which can be selected from aluminum nitride (AlN), zinc oxide (ZnO), lead zirconate titanate (PZT), Materials such as lithium niobate (LiNbO3), quartz (Quartz), potassium niobate (KNbO3) or lithium tantalate (LiTaO3), doped with 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), lutet
  • AlN aluminum
  • a single-layer top electrode or a top electrode layer in a top electrode stack its material 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, and the above metals alloy, etc.
  • the material of the top electrode and the bottom electrode may be the same or different. In Figure 2, no passivation layer is provided over the top electrode, but as can be appreciated, a passivation layer may also be provided.
  • Passivation layer the material of the passivation layer includes but not limited to polysilicon SiO2, Si3N4, AlN and the like.
  • the material of the protruding structure is the same as the top electrode 130 or the bottom electrode 150 or the piezoelectric layer 140 .
  • the raised structure is located at the edge of the effective area, and the raised structure can reduce the acoustic impedance of the effective area where it is located.
  • the material of the protruding structure is metal tungsten.
  • FIG. 1 A schematic cross-sectional view of the bulk acoustic wave resonator according to the present invention is also shown in FIG. 1 .
  • the material of the bottom electrode 30 and the top electrode 50 of the resonator is molybdenum
  • the material of the piezoelectric layer 40 is scandium-doped aluminum nitride.
  • the thicknesses of the bottom electrode 30 and the top electrode 50 are equal to t, and the thickness of the piezoelectric layer 40 is d.
  • the thickness ratio t/d of the thickness of the single-layer electrode and the piezoelectric layer affects the effective electromechanical coupling coefficient of the resonator, which in turn affects the bandwidth of the resonator (the larger the effective electromechanical coupling coefficient, the larger the bandwidth).
  • FIG. 2 exemplarily shows the relationship between the ratio of the thickness of the single-layer electrode to the thickness of the piezoelectric layer and the electromechanical coupling coefficient of the resonator in the case where the thicknesses of the top and bottom electrodes are the same, wherein the respective The piezoelectric layer is aluminum nitride and the electrodes are all molybdenum, the piezoelectric layer is scandium-doped aluminum nitride and the electrodes are all molybdenum, the piezoelectric layer is scandium-doped aluminum nitride and the electrodes are all tungsten.
  • the abscissa is the thickness ratio t/d of the thickness of the single-layer electrode and the piezoelectric layer
  • the ordinate is the effective electromechanical coupling coefficient (Kt2eff) of the resonator
  • the actual The line is 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 is the effective electromechanical coupling coefficient when the bottom electrode and the top electrode are molybdenum
  • the piezoelectric layer is 3% scandium-doped aluminum nitride.
  • the effective electromechanical coupling coefficient curve is overall improved; the dotted line is 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 overall effective electromechanical coupling coefficient curve is further improved.
  • the traditional bulk acoustic wave resonator uses molybdenum as the electrode.
  • the thickness ratio of the electrode to the piezoelectric layer thickness is t/d Increase the thickness of the electrode, the thickness of the piezoelectric layer becomes thinner, and the area A required to match to 50 ohms is smaller, which can achieve the purpose of reducing the area A of the effective area to increase the number of resonators, thereby reducing the manufacturing cost, but shrinking This area A will at the same time degrade the power capacity of the resonator.
  • the tungsten electrode is used instead of the molybdenum electrode.
  • the thermal conductivity of the tungsten electrode (1.73) is greater than that of the molybdenum electrode (1.38), and the thermal conductivity of the tungsten electrode is better.
  • the tungsten electrode can further improve the effective electromechanical coupling coefficient.
  • the thickness ratio t/d of the thickness of the electrode and the piezoelectric layer can be larger.
  • the thickness of the tungsten electrode The increase can reduce the resistance of the film electrode and reduce the heat generation of the electrode resistance, and because the electrode material has better thermal conductivity than the piezoelectric layer material, the resonator can withstand a higher power density and have a higher power capacity.
  • tungsten electrode in a resonator having a scandium-doped aluminum nitride piezoelectric layer can ensure the power capacity of the resonator while reducing the area A of the effective region of the resonator.
  • Scandium-doped aluminum nitride is used as the piezoelectric layer and tungsten is used as the electrode material, which can not only reduce the area of the resonator, make more resonators integrated in a single wafer, but also ensure the power capacity of the resonator, which will not be damaged under high power. .
  • the bottom electrode 130 and the top electrode 150 are tungsten electrodes with different thicknesses (t1>t2 or t1 ⁇ t2), and the piezoelectric layer 140 has different doping concentrations of aluminum nitride or other piezoelectric materials.
  • the bottom electrode 130 is a tungsten electrode
  • the top electrode 150 is a molybdenum electrode or other electrode materials
  • the piezoelectric layer 140 is made of aluminum nitride or other piezoelectric materials with different doping concentrations.
  • the bottom electrode 130 is a molybdenum electrode or other electrode materials
  • the top electrode 150 is a tungsten electrode
  • the piezoelectric layer 140 is made of aluminum nitride or other piezoelectric materials with different doping concentrations.
  • FIG. 4 The structure shown in FIG. 4 is similar to that in FIG. 3 , the difference is that in FIG. 4 , a passivation layer 160 is added on the top electrode 150 .
  • FIG. 5 The structure shown in FIG. 5 is similar to that shown in FIG. 3 , the difference is that in FIG. 5 , a protruding structure 170 is added on the top electrode 150 .
  • FIG. 6 The structure shown in FIG. 6 is similar to that in FIG. 5 , the difference is that in FIG. 6 , a protruding structure 170 and a passivation layer 160 are added on the top electrode 150 .
  • the top electrode or the bottom electrode is a single-layer electrode structure, but the present invention is not limited thereto.
  • the electrodes may also be in a laminated structure, and in this case, one electrode layer in the laminated electrode may be a tungsten electrode layer.
  • Figures 7-12 illustrate embodiments of resonators with stacked electrodes. Below is an example description:
  • the top electrode is composed of a laminated structure of a first top electrode 260 and a second top electrode 270
  • the bottom electrode is composed of a laminated structure of a first bottom electrode 240 and a second bottom electrode 230, wherein 260 and 240 are tungsten electrodes, 270 and 230 may be other electrode material layers.
  • FIG. 8 The structure shown in FIG. 8 is similar to that shown in FIG. 7 , except that the top electrode in FIG. 8 is only 260 , wherein 260 and 240 are tungsten electrodes, and 230 can be other electrode material layers.
  • FIG. 9 The structure shown in FIG. 9 is similar to that shown in FIG. 7 , except that the bottom electrode in FIG. 9 is only 240 , wherein 260 and 240 are tungsten electrodes, and 270 can be other electrode material layers.
  • the top electrode is composed of a stacked structure of the first top electrode 370 , the second top electrode 380 and the third top electrode 390
  • the bottom electrode is composed of the first bottom electrode 350 , the second bottom electrode 340 and the third bottom electrode 330
  • the layered structure is composed, wherein 370 and 350 are tungsten electrodes, 330, 340, 380 and 390 can be other electrode material layers, and 330 and 390 can still be tungsten electrodes.
  • FIG. 11 The structure shown in FIG. 11 is similar to that shown in FIG. 10 , except that the top electrode in FIG. 11 has only 370 , wherein 370 and 350 are tungsten electrodes, 330 and 340 can be other electrode material layers, and 330 can be a tungsten electrode.
  • FIG. 12 The structure shown in FIG. 12 is similar to that shown in FIG. 10 , the difference is that the bottom electrode in FIG. 12 is only 240 , 370 and 350 are tungsten electrodes, 380 and 390 can be other electrode materials, and 390 can be a tungsten electrode.
  • tungsten electrode layers are provided on both the upper and lower sides of the piezoelectric layer, but the present invention is not limited to this, for example, a tungsten electrode layer may be provided only on one side of the piezoelectric layer.
  • the tungsten electrode or the tungsten electrode layer is formed of metal tungsten, but the present invention is not limited to this, and the tungsten electrode or the tungsten electrode layer can also be formed by using a tungsten alloy (ie an alloy containing metal tungsten), which is both within the protection scope of the present invention.
  • a tungsten alloy ie an alloy containing metal tungsten
  • each numerical range except that it is clearly indicated that it does not include the endpoint value, can be the endpoint value, and can also be the median value of each numerical range, and these are all within the protection scope of the present invention. .
  • upper and lower are relative to the bottom surface of the base of the resonator.
  • the side close to the bottom surface is the lower side, and the side away from the bottom surface is the upper side.
  • inner and outer are relative to the center of the effective area of the resonator (ie, the center of the effective area) in the lateral direction or the radial direction, and one side or one end of a component close to the center of the effective area is the inner side or inner end, and the side or end of the part away from the center of the active area is the outer or outer end.
  • being located inside the position means being between the position and the center of the effective area in the lateral or radial direction, and being located outside of the position means being farther from the position in the lateral or radial direction than the position Effective regional center.
  • BAW resonators may be used to form filters or electronic devices.
  • the electronic equipment here includes but is not limited to intermediate products such as RF front-end, filter and amplifier modules, and terminal products such as mobile phones, WIFI, and drones.
  • a bulk acoustic wave resonator comprising:
  • a piezoelectric layer arranged between the bottom electrode and the top electrode
  • the piezoelectric layer is a doped piezoelectric layer
  • the top electrode and/or the bottom electrode are tungsten electrodes containing metal tungsten.
  • the top electrode and/or the bottom electrode is a single-layer electrode made of metal tungsten or a single-layer electrode made of tungsten alloy.
  • the top and bottom electrodes are both tungsten electrodes.
  • the ratio of the monolayer thickness of the top or bottom electrode to the thickness of the doped piezoelectric layer is in the range of 0.1-1.
  • 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.
  • 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 that of the non-tungsten electrode; or
  • 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 that of the non-tungsten electrode.
  • the top electrode and/or the bottom electrode are stacked electrodes, and the stacked electrode includes at least two stacked electrode layers of different materials, and the at least two electrode layers include at least one tungsten electrode layer.
  • the electrode layer is an electrode layer made of metal tungsten or an electrode layer made of a tungsten alloy.
  • the electrode layer adjacent to the piezoelectric layer of the stacked electrode is a first electrode layer, and the first electrode layer is a tungsten electrode layer.
  • the top electrode and the bottom electrode are both stacked 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.
  • One of the top electrode and the bottom electrode is a laminated electrode, and the other is a non-laminated electrode.
  • the piezoelectric layer is scandium-doped aluminum nitride.
  • the resonator further includes a protruding structure arranged along the effective area, and the material of the protruding structure is tungsten.
  • a filter comprising the bulk acoustic wave resonator according to any one of 1-12.
  • An electronic device comprising the filter according to 13 or the resonator according to any one of 1-12.

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Abstract

The present invention relates to a bulk acoustic 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 metal tungsten. 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. Alternatively, the top electrode and/or the bottom electrode is a stacked electrode comprising at least two electrode layers made of different materials and arranged in a stacked manner. The at least two electrode layers include at least one tungsten electrode layer. The tungsten electrode layer is an electrode layer made of metal tungsten or an electrode layer made of a tungsten alloy. The present invention also relates to a filter having the above resonator and an electronic device having the filter or the resonator.

Description

具有钨电极的体声波谐振器、滤波器及电子设备Bulk Acoustic Resonators, Filters, and Electronic Devices with Tungsten Electrodes 技术领域technical field
本发明的实施例涉及半导体领域，尤其涉及一种体声波谐振器、一种具有该谐振器的滤波器，以及一种具有该谐振器或者该滤波器的电子设备。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.
背景技术Background technique
电子器件作为电子设备的基本元素，已经被广泛应用，其应用范围包括移动电话、汽车、家电设备等。此外，未来即将改变世界的人工智能、物联网、5G通讯等技术仍然需要依靠电子器件作为基础。As the basic elements of electronic equipment, electronic devices have been widely used, and their applications include mobile phones, automobiles, home appliances and so on. In addition, technologies such as artificial intelligence, the Internet of Things, and 5G communications that will change the world in the future still need to rely on electronic devices as their foundation.
电子器件根据不同工作原理可以发挥不同的特性与优势，在所有电子器件中，利用压电效应(或逆压电效应)工作的器件是其中很重要一类，压电器件有着非常广泛的应用情景。薄膜体声波谐振器(Film Bulk Acoustic Resonator，简称FBAR，又称为体声波谐振器，也称BAW)作为压电器件的重要成员正在通信领域发挥着重要作用，特别是FBAR滤波器在射频滤波器领域市场占有份额越来越大，FBAR具有尺寸小、谐振频率高、品质因数高、功率容量大、滚降效应好等优良特性，其滤波器正在逐步取代传统的声表面波(SAW)滤波器和陶瓷滤波器，在无线通信射频领域发挥巨大作用，其高灵敏度的优势也能应用到生物、物理、医学等传感领域。Electronic devices can play different characteristics and advantages according to different working principles. Among all electronic devices, devices that use the piezoelectric effect (or inverse piezoelectric effect) are one of the most important categories. Piezoelectric devices have a very wide range of application scenarios. . Film Bulk Acoustic Resonator (FBAR, also known as Bulk Acoustic Resonator, also known as BAW) as an important member of piezoelectric devices is playing an important role in the field of communication, especially FBAR filter in radio frequency filter The market share in the field is increasing. FBAR has excellent characteristics such as small size, high resonant frequency, high quality factor, large power capacity, and good roll-off effect. Its filters are gradually replacing traditional surface acoustic wave (SAW) filters And ceramic filters, play a huge role in the field of wireless communication radio frequency, its high sensitivity advantage can also be applied to biological, physical, medical and other sensing fields.
传统薄膜体声波谐振器的截面示意图如图1所示，在图1中，例如底电极30和顶电极50的材料为钼，压电层40材料为氮化铝。底电极30和顶电极50的厚度相等为t,压电层40厚度为d。单层电极与压电层厚度的厚度比t/d会影响谐振器的有效机电耦合系数，进而影响谐振器的带宽(有效机电耦合系数越大，带宽越大)。薄膜体声波谐振器在设计中需将阻抗匹配到50欧姆，相同频率及带宽下，压电层厚度越薄，有效区域的面积A可以越小，从而在单片晶圆上集成的谐振器数量越多，能够节省制造成本。A schematic cross-sectional view of a conventional thin film bulk acoustic resonator is shown in FIG. 1 . In FIG. 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 to t, and the thickness of the piezoelectric layer 40 is d. The thickness ratio t/d of the thickness of the monolayer electrode and the piezoelectric layer affects the effective electromechanical coupling coefficient of the resonator, which in turn affects the bandwidth of the resonator (the larger the effective electromechanical coupling coefficient, the larger the bandwidth). In the design of thin-film bulk acoustic wave resonators, the impedance needs to be matched to 50 ohms. Under the same frequency and bandwidth, the thinner the piezoelectric layer is, the smaller the area A of the effective area can be, so that the number of resonators integrated on a single wafer can be reduced. The more, the manufacturing cost can be saved.
压电层厚度减薄通常的方法是采用掺钪氮化铝作为压电层，使其机电耦合系数上升，要求相同带宽时，可以取更大的单层电极与压电层厚度的比t/d，从而达到减薄压电层厚度的目的，匹配50欧姆可以缩小谐振器面积A。The usual method for reducing the thickness of the piezoelectric layer is to use scandium-doped aluminum nitride as the piezoelectric layer to increase the electromechanical coupling coefficient. When the same bandwidth is required, a larger ratio of the thickness of the single-layer electrode to the piezoelectric layer, t/ d, so as to achieve the purpose of reducing the thickness of the piezoelectric layer, matching 50 ohms can reduce the area A of the resonator.
但上述方法带来的问题是：在相同功率密度下，面积缩小会使谐振器的 功率容量变小。However, the problem brought by the above method is: under the same power density, the reduction of the area will reduce the power capacity of the resonator.
发明内容SUMMARY OF THE INVENTION
为了既可以缩小谐振器的有效区域的面积，又可以保证谐振器的功率容量，例如为了解决引入掺钪氮化铝作为压电层后谐振器的有效区域的面积变小所带来的功率容量变差的问题，提出本发明。In order to reduce the area of the effective area of the resonator and ensure the power capacity of the resonator, for example, in order to solve the power capacity caused by the reduction of the area of the effective area of the resonator after introducing scandium-doped aluminum nitride as the piezoelectric layer The problem of deterioration, the present invention is proposed.
根据本发明的实施例的一个方面，提出了一种体声波谐振器，包括：According to an aspect of the embodiments of the present invention, a bulk acoustic wave resonator is proposed, comprising:
基底；base;
声学镜；acoustic mirror;
底电极；bottom electrode;
顶电极；和top electrode; and
压电层，设置在底电极与顶电极之间，a piezoelectric layer, arranged between the bottom electrode and the top electrode,
其中：in:
所述压电层为掺杂压电层；且the piezoelectric layer is a doped piezoelectric layer; and
所述顶电极和/或底电极为含有金属钨的钨电极。The top electrode and/or the bottom electrode are tungsten electrodes containing metal tungsten.
可选的，所述顶电极和/或底电极为由金属钨制成的单层电极或者由钨合金制成的单层电极。Optionally, the top electrode and/or the bottom electrode is a single-layer electrode made of metal tungsten or a single-layer electrode made of tungsten alloy.
或者可选的，所述顶电极和/或底电极为叠层电极，所述叠层电极包括叠置的不同材质的至少两层电极层，所述至少两层电极层至少包括一层钨电极层，所述钨电极层为由金属钨制成的电极层或者由钨合金制成的电极层。Alternatively, the top electrode and/or the bottom electrode are stacked electrodes, the stacked electrodes include at least two stacked electrode layers of different materials, and the at least two electrode layers include at least one layer of tungsten electrodes The tungsten electrode layer is an electrode layer made of metal tungsten or an electrode layer made of tungsten alloy.
本发明的实施例还涉及一种滤波器，包括上述的体声波谐振器。Embodiments of the present invention also relate to a filter comprising the above-mentioned bulk acoustic wave resonator.
本发明的实施例也涉及一种电子设备，包括上述的滤波器或者上述的谐振器。Embodiments of the present invention also relate to an electronic device comprising the above-mentioned filter or the above-mentioned resonator.
附图说明Description of drawings
以下描述与附图可以更好地帮助理解本发明所公布的各种实施例中的这些和其他特点、优点，图中相同的附图标记始终表示相同的部件，其中：These and other features and advantages of the various disclosed embodiments of the present invention may be better understood by the following description and accompanying drawings, in which like reference numerals refer to like parts throughout, wherein:
图1为传统薄膜体声波谐振器的截面示意图；1 is a schematic cross-sectional view of a conventional thin-film bulk acoustic resonator;
图2示例性示出了在顶电极与底电极的厚度相同的情况下，单层电极的厚度与压电层的厚度之比与谐振器的机电耦合系数之间的关系图，其中分别示出了压电层为氮化铝以及电极均为钼、压电层为掺钪氮化铝以及电极均为 钼、压电层为掺钪氮化铝以及电极均为钨这三种情形；FIG. 2 exemplarily shows the relationship between the ratio of the thickness of the single-layer electrode to the thickness of the piezoelectric layer and the electromechanical coupling coefficient of the resonator in the case where the thicknesses of the top and bottom electrodes are the same, wherein the respective The three cases are that the piezoelectric layer is aluminum nitride, the electrodes are all molybdenum, the piezoelectric layer is scandium-doped aluminum nitride, the electrodes are all molybdenum, the piezoelectric layer is scandium-doped aluminum nitride, and the electrodes are all tungsten;
图3-12分别示出了本发明的不同实施例的体声波谐振器的截面示意图。3-12 respectively illustrate schematic cross-sectional views of bulk acoustic wave resonators according to different embodiments of the present invention.
具体实施方式Detailed ways
下面通过实施例，并结合附图，对本发明的技术方案作进一步具体的说明。在说明书中，相同或相似的附图标号指示相同或相似的部件。下述参照附图对本发明实施方式的说明旨在对本发明的总体发明构思进行解释，而不应当理解为对本发明的一种限制。The technical solutions of the present invention will be further described in detail below through embodiments and in conjunction with the accompanying drawings. In the specification, the same or similar reference numerals refer to the same or similar parts. The following description of the embodiments of the present invention with reference to the accompanying drawings is intended to explain the general inventive concept of the present invention, and should not be construed as a limitation of the present invention.
如本领域技术人员所知的，采用掺杂压电层代替压电层，在同样的机电耦合系数和频率的情况下，谐振器的有效区域的面积会变小，而谐振器的有效区域的面积变小，在相同功率密度的情况下，会使得谐振器的功率容量变小。As known to those skilled in the art, if a doped piezoelectric layer is used instead of the piezoelectric layer, under the same electromechanical coupling coefficient and frequency, the area of the effective area of the resonator will become smaller, while the area of the effective area of the resonator will become smaller. The smaller the area, the smaller the power capacity of the resonator at the same power density.
而且，如本领域技术人员所知的，在同样的机电耦合系数和频率的情况下，若将谐振器的钼电极替换为钨电极，谐振器的有效区域的面积会变小，这不利于保持较大的功率容量。Moreover, as known to those skilled in the art, under the same electromechanical coupling coefficient and frequency, if the molybdenum electrode of the resonator is replaced with a tungsten electrode, the area of the effective area of the resonator will become smaller, which is not conducive to maintaining larger power capacity.
此外，如本领域技术人员所知的，金属钨在常温时的薄膜电阻率为20-30微欧姆每厘米，金属钼在常温时的薄膜电阻率为大约10微欧姆每厘米，可见，在常温时，金属钨的薄膜电阻率远大于金属钼在常温时的薄膜电阻率。因此，一般会认为，在谐振器工作过程中以钨作为电极的钨电极电阻大于以钼作为电极的钼电极电阻，从而钨电极由于电流流过电阻带来产热相较于钼电极较大。在这种情况下，若用钨电极代替谐振器的钼电极会直接导致谐振器的电极在工作过程中的放热加大，这在谐振器的有效区域的面积一定的情况下不利于保持较大的功率容量。因此，本领域技术人员基于保持较大的功率容量，不会想到将谐振器的钼电极替换为钨电极。In addition, as known to those skilled in the art, the sheet resistivity of metal tungsten at room temperature is 20-30 microohms per centimeter, and the sheet resistivity of metal molybdenum at room temperature is about 10 microohms per centimeter. It can be seen that at room temperature , the film resistivity of metal tungsten is much greater than that of metal molybdenum at room temperature. Therefore, it is generally believed that the resistance of the tungsten electrode with tungsten as the electrode is greater than that of the molybdenum electrode with molybdenum as the electrode during the working process of the resonator, so that the heat generated by the tungsten electrode due to the current flowing through the resistance is larger 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 release of the electrode of the resonator during operation. large power capacity. Therefore, those skilled in the art would not think of replacing the molybdenum electrodes of the resonators with tungsten electrodes based on maintaining a large power capacity.
基于以上，对于采用钼电极以及掺杂压电层的谐振器(其已经基于掺杂而具有较小的有效区域的面积)，本领域技术人员的通常做法是尽量避免将采用钼电极以及掺杂压电层的谐振器中的钼电极替换为钨电极，因为使用钨电极会进一步减小有效区域的面积而不利于保持较好的功率容量。Based on the above, for resonators using molybdenum electrodes and doped piezoelectric layers (which already have a smaller effective area based on doping), it is common practice for those skilled in the art to try to avoid using molybdenum electrodes and doping The molybdenum electrode in the resonator of the piezoelectric layer is replaced with a tungsten electrode, because the use of a tungsten electrode will further reduce the area of the active area and is not conducive to maintaining a good power capacity.
但是，发明人发现，若将采用钼电极以及掺杂压电层的谐振器中的钼电极替换为钨电极，可以在缩小谐振器的有效区域的面积的同时，保证谐振器 的功率容量。However, the inventors found that if the molybdenum electrodes in the resonators using molybdenum electrodes and doped piezoelectric layers are replaced with tungsten electrodes, the area of the effective region of the resonator can be reduced, and the power capacity of the resonator can be ensured.
基于以上，本发明提出了在体声波谐振器中，将掺杂压电层(可以降低谐振器的有效区域的面积)与钨电极(可以降低谐振器的有效区域的面积)相结合的技术方案。Based on the above, the present invention proposes a technical solution of combining a doped piezoelectric layer (which can reduce the area of the effective area of the resonator) and a tungsten electrode (which can reduce the area of the effective area of the resonator) in a bulk acoustic wave resonator .
以下参照附图2-12具体说明本发明的技术方案。在本发明中，附图标记简单说明如下：The technical solutions of the present invention will be specifically described below with reference to accompanying drawings 2-12. In the present invention, the reference numerals are briefly described as follows:
110、210、310：基底，可选材料为单晶硅、石英、砷化镓或蓝宝石等。110, 210, 310: substrate, the optional material is single crystal silicon, quartz, gallium arsenide or sapphire, etc.
120、220、320：声学镜，其位于基底110的上表面或嵌于基底的内部，在本发明中声学镜为嵌入基底中的空腔所构成，但是声学镜也可以为布拉格反射层及其他等效形式。120, 220, 320: acoustic mirrors, which are located on the upper surface of the substrate 110 or embedded in the interior of the substrate. In the present invention, the acoustic mirror is formed by a cavity embedded in the substrate, but the acoustic mirror can also be a Bragg reflection layer and other Equivalent form.
130、230、240、330、340、350：单层底电极或底电极叠层中的一个底电极层，其可以沉积在声学镜的上表面，并覆盖声学镜。可将底电极130边缘刻蚀成斜面，并且该斜面与谐振器的有效区域边缘对齐，此外底电极130的边缘还可以为阶梯状、垂直状或是其它相似的结构。底电极的材料可为：金(Au)、钨(W)、钼(Mo)、铂(Pt)，钌(Ru)、铱(Ir)、钛钨(TiW)、铝(Al)、钛(Ti)、锇(Os)、镁(Mg)、金(Au)、钨(W)、钼(Mo)、铂(Pt)、钌(Ru)、铱(Ir)、锗(Ge)、铜(Cu)、铝(Al)、铬(Cr)、砷掺杂金等类似金属，以及以上金属的合金等。130, 230, 240, 330, 340, 350: A single-layer bottom electrode or a bottom electrode layer in a bottom electrode stack, which may be deposited on the upper surface of the acoustic mirror and cover the acoustic mirror. The edge of the bottom electrode 130 can be etched into a bevel, and the bevel is aligned with the edge of the effective area of the resonator, and 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 other similar metals, as well as alloys of the above metals.
140、250、360：压电薄膜层或压电层，可选为包括一定原子比的稀土元素掺杂材料的氮化铝(AlN)、氧化锌(ZnO)、锆钛酸铅(PZT)、铌酸锂(LiNbO3)、石英(Quartz)、铌酸钾(KNbO3)或钽酸锂(LiTaO3)等材料，掺杂元素如钪(Sc)、钇(Y)、镁(Mg)、钛(Ti)、镧(La)、铈(Ce)、镨(Pr)、钕(Nd)、钷(Pm)、钐(Sm)、铕(Eu)、钆(Gd)、铽(Tb)、镝(Dy)、钬(Ho)、铒(Er)、铥(Tm)、镱(Yb)、镥(Lu)等。140, 250, 360: piezoelectric thin film layer or piezoelectric layer, which can be selected from aluminum nitride (AlN), zinc oxide (ZnO), lead zirconate titanate (PZT), Materials such as lithium niobate (LiNbO3), quartz (Quartz), potassium niobate (KNbO3) or lithium tantalate (LiTaO3), doped with 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.
150、260、270、370、380、390：单层顶电极或顶电极叠层中的一个顶电极层，其材料可为：金(Au)、钨(W)、钼(Mo)、铂(Pt)，钌(Ru)、铱(Ir)、钛钨(TiW)、铝(Al)、钛(Ti)、锇(Os)、镁(Mg)、金(Au)、钨(W)、钼(Mo)、铂(Pt)、钌(Ru)、铱(Ir)、锗(Ge)、铜(Cu)、铝(Al)、铬(Cr)、砷掺杂金等类似金属，以及以上金属的合金等。顶电极的材料与底电极可以相同也可以不同。在图2中，顶电极上方并未设置钝化层，但是如能够理解的， 也可以设置钝化层。150, 260, 270, 370, 380, 390: a single-layer top electrode or a top electrode layer in a top electrode stack, its material 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, and the above metals alloy, etc. The material of the top electrode and the bottom electrode may be the same or different. In Figure 2, no passivation layer is provided over the top electrode, but as can be appreciated, a passivation layer may also be provided.
160：钝化层，钝化层材料包括但不限于多晶硅SiO2、Si3N4、AlN等。160: Passivation layer, the material of the passivation layer includes but not limited to polysilicon SiO2, Si3N4, AlN and the like.
170：凸起结构，凸起结构的材料同顶电极130或底电极150或压电层140。凸起结构位于有效区域的边缘位置，凸起结构可以降低其所在有效区域的声阻抗。在本发明的一个实施例中，凸起结构的材料为金属钨。170 : a protruding structure, the material of the protruding structure is the same as the top electrode 130 or the bottom electrode 150 or the piezoelectric layer 140 . The raised structure is located at the edge of the effective area, and the raised structure can reduce the acoustic impedance of the effective area where it is located. In an embodiment of the present invention, the material of the protruding structure is metal tungsten.
根据本发明的体声波谐振器的截面示意图同样如图1所示。在一个具体的示例中，谐振器的底电极30和顶电极50的材料为钼，压电层40材料为掺钪氮化铝。底电极30和顶电极50的厚度相等为t,压电层40厚度为d。单层电极与压电层厚度的厚度比(thickness ratio)t/d会影响谐振器的有效机电耦合系数，进而影响谐振器的带宽(有效机电耦合系数越大，带宽越大)。A schematic cross-sectional view of the bulk acoustic wave resonator according to the present invention is also shown in FIG. 1 . In a specific example, the material of the bottom electrode 30 and the top electrode 50 of the resonator is molybdenum, and the material of the piezoelectric layer 40 is scandium-doped aluminum nitride. The thicknesses of the bottom electrode 30 and the top electrode 50 are equal to t, and the thickness of the piezoelectric layer 40 is d. The thickness ratio t/d of the thickness of the single-layer electrode and the piezoelectric layer affects the effective electromechanical coupling coefficient of the resonator, which in turn affects the bandwidth of the resonator (the larger the effective electromechanical coupling coefficient, the larger the bandwidth).
图2示例性示出了在顶电极与底电极的厚度相同的情况下，单层电极的厚度与压电层的厚度之比与谐振器的机电耦合系数之间的关系图，其中分别示出了压电层为氮化铝以及电极均为钼、压电层为掺钪氮化铝以及电极均为钼、压电层为掺钪氮化铝以及电极均为钨这三种情形。FIG. 2 exemplarily shows the relationship between the ratio of the thickness of the single-layer electrode to the thickness of the piezoelectric layer and the electromechanical coupling coefficient of the resonator in the case where the thicknesses of the top and bottom electrodes are the same, wherein the respective The piezoelectric layer is aluminum nitride and the electrodes are all molybdenum, the piezoelectric layer is scandium-doped aluminum nitride and the electrodes are all molybdenum, the piezoelectric layer is scandium-doped aluminum nitride and the electrodes are all tungsten.
如图2所示，假设底电极30和顶电极50厚度相同，横坐标为单层电极与压电层厚度的厚度比t/d，纵坐标为谐振器的有效机电耦合系数(Kt2eff)，实线为底电极与顶电极为钼，压电层为氮化铝时的有效机电耦合系数；虚线为底电极与顶电极为钼，压电层为3％的掺钪氮化铝时的有效机电耦合系数，有效机电耦合系数曲线整体提升；点划线为底电极与顶电极为钨，压电层为3％的掺钪氮化铝时的有效机电耦合系数，有效机电耦合系数曲线整体进一步提升。传统体声波谐振器用钼作电极，当压电层采用掺钪氮化铝时，同一频率下，相比于压电层是氮化铝的情况，电极与压电层厚度的厚度比t/d增大，电极厚度加厚，压电层厚度变薄，匹配到50欧姆所需的面积A更小，能够到达缩小有效区域的面积A以增加谐振器数量的目的，从而降低制造成本，但缩小该面积A的同时会使谐振器的功率容量变差。As shown in FIG. 2 , assuming that the bottom electrode 30 and the top electrode 50 have the same thickness, the abscissa is the thickness ratio t/d of the thickness of the single-layer electrode and the piezoelectric layer, the ordinate is the effective electromechanical coupling coefficient (Kt2eff) of the resonator, and the actual The line is 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 is 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. Coupling coefficient, the effective electromechanical coupling coefficient curve is overall improved; the dotted line is 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 overall effective electromechanical coupling coefficient curve is further improved. . The traditional bulk acoustic wave resonator uses molybdenum as the electrode. When the piezoelectric layer uses scandium-doped aluminum nitride, at the same frequency, compared with the case where the piezoelectric layer is aluminum nitride, the thickness ratio of the electrode to the piezoelectric layer thickness is t/d Increase the thickness of the electrode, the thickness of the piezoelectric layer becomes thinner, and the area A required to match to 50 ohms is smaller, which can achieve the purpose of reducing the area A of the effective area to increase the number of resonators, thereby reducing the manufacturing cost, but shrinking This area A will at the same time degrade the power capacity of the resonator.
本发明中，用钨电极代替钼电极，一方面钨电极的导热系数(1.73)大于钼电极(1.38)，钨电极的导热性更好，使得的谐振器能承受的功率密度更大，能够有更高的功率容量；另一方面钨电极能进一步提升有效机电耦合系数，相同有效机电耦合系数时，电极与压电层厚度的厚度比t/d能够更大，相对于钼电极，钨电极厚度增加可以减小薄膜电极的电阻，减小电极电阻产 热，而且由于电极材料比压电层材料导热性更好，使得的谐振器能承受的功率密度更大，能够有更高的功率容量。In the present invention, the tungsten electrode is used instead of the molybdenum electrode. On the one hand, the thermal conductivity of the tungsten electrode (1.73) is greater than that of the molybdenum electrode (1.38), and the thermal conductivity of the tungsten electrode is better. Higher power capacity; on the other hand, the tungsten electrode can further improve the effective electromechanical coupling coefficient. When the effective electromechanical coupling coefficient is the same, the thickness ratio t/d of the thickness of the electrode and the piezoelectric layer can be larger. Compared with the molybdenum electrode, the thickness of the tungsten electrode The increase can reduce the resistance of the film electrode and reduce the heat generation of the electrode resistance, and because the electrode material has better thermal conductivity than the piezoelectric layer material, the resonator can withstand a higher power density and have a higher power capacity.
因此，在本发明中，在具有掺钪的氮化铝压电层的谐振器中使用钨电极，可以在缩小谐振器的有效区域的面积A的同时保证谐振器的功率容量。掺钪氮化铝作为压电层，钨作为电极材料，既可以缩小谐振器面积，使单片晶圆集成的谐振器更多，又可以保证谐振器的功率容量，在大功率下不至于损坏。Therefore, in the present invention, using a tungsten electrode in a resonator having a scandium-doped aluminum nitride piezoelectric layer can ensure the power capacity of the resonator while reducing the area A of the effective region of the resonator. Scandium-doped aluminum nitride is used as the piezoelectric layer and tungsten is used as the electrode material, which can not only reduce the area of the resonator, make more resonators integrated in a single wafer, but also ensure the power capacity of the resonator, which will not be damaged under high power. .
下面参照图3-12示例性说明本发明的不同实施例。Various embodiments of the present invention are exemplified below with reference to FIGS. 3-12.
如图3所示，在本发明的一个实施例中，底电极130和顶电极150为钨电极，且厚度相同(t1＝t2)，压电层140为掺杂浓度不同的氮化铝或其他压电材料。As shown in FIG. 3 , 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 made of aluminum nitride or other materials with different doping concentrations. Piezoelectric material.
在可选的实施例中，在图3所示的结构中，底电极130和顶电极150为钨电极，但厚度不同(t1>t2或t1<t2)，压电层140为掺杂浓度不同的氮化铝或其他压电材料。In an optional embodiment, in the structure shown in FIG. 3 , the bottom electrode 130 and the top electrode 150 are tungsten electrodes with different thicknesses (t1>t2 or t1<t2), and the piezoelectric layer 140 has different doping concentrations of aluminum nitride or other piezoelectric materials.
在可选的实施例中，在图3所示的结构中，底电极130为钨电极，顶电极150为钼电极或其他电极材料，且顶电极与底电极的厚度相同或不同(t1＝t2或t1>t2或t1<t2)，压电层140为掺杂浓度不同的氮化铝或其他压电材料。In an optional embodiment, in the structure shown in FIG. 3 , the bottom electrode 130 is a tungsten electrode, the top electrode 150 is a molybdenum electrode or other electrode materials, and the thicknesses of the top electrode and the bottom electrode are the same or different (t1=t2 Or t1>t2 or t1<t2), the piezoelectric layer 140 is made of aluminum nitride or other piezoelectric materials with different doping concentrations.
在可选的实施例中，在图3所示的结构中，底电极130为钼电极或其他电极材料，顶电极150为钨电极，且厚度相同或不同(t1＝t2或t1>t2或t1<t2)，压电层140为掺杂浓度不同的氮化铝或其他压电材料。In an optional embodiment, in the structure shown in FIG. 3 , the bottom electrode 130 is a molybdenum electrode or other electrode materials, 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), the piezoelectric layer 140 is made of aluminum nitride or other piezoelectric materials with different doping concentrations.
图4所示的结构与图3相类似，不同之处在于在图4中，顶电极150上加了钝化层160。The structure shown in FIG. 4 is similar to that in FIG. 3 , the difference is that in FIG. 4 , a passivation layer 160 is added on the top electrode 150 .
图5所示的的结构与图3相类似，不同之处在于在图5中，顶电极150上加了凸起结构170。The structure shown in FIG. 5 is similar to that shown in FIG. 3 , the difference is that in FIG. 5 , a protruding structure 170 is added on the top electrode 150 .
图6所示结构与图5相类似，不同之处在于在图6中，顶电极150上加了凸起结构170和钝化层160。The structure shown in FIG. 6 is similar to that in FIG. 5 , the difference is that in FIG. 6 , a protruding structure 170 and a passivation layer 160 are added on the top electrode 150 .
图3-6所示的结构中，顶电极或底电极为单层电极结构，但是本发明不限于此。电极也可以为叠层结构，此时叠层电极中的一个电极层可以是钨电极层。图7-图12示出了叠层电极的谐振器实施例。下面示例性说明：In the structures shown in FIGS. 3-6 , the top electrode or the bottom electrode is a single-layer electrode structure, but the present invention is not limited thereto. The electrodes may also be in a laminated structure, and in this case, one electrode layer in the laminated electrode may be a tungsten electrode layer. Figures 7-12 illustrate embodiments of resonators with stacked electrodes. Below is an example description:
图7中，顶电极由第一顶电极260和第二顶电极270的层叠结构组成， 底电极由第一底电极240和第二底电极230的层叠结构组成，其中260与240为钨电极，270与230可为其他电极材料层。In FIG. 7, the top electrode is composed of a laminated structure of a first top electrode 260 and a second top electrode 270, and the bottom electrode is composed of a laminated structure of a first bottom electrode 240 and a second bottom electrode 230, wherein 260 and 240 are tungsten electrodes, 270 and 230 may be other electrode material layers.
图8所示结构与图7类似，不同之处在于图8中的顶电极只有260，其中260与240为钨电极，230可为其他电极材料层。The structure shown in FIG. 8 is similar to that shown in FIG. 7 , except that the top electrode in FIG. 8 is only 260 , wherein 260 and 240 are tungsten electrodes, and 230 can be other electrode material layers.
图9所示结构与图7类似，不同之处在于图9中的底电极只有240，其中260与240为钨电极，270可为其他电极材料层。The structure shown in FIG. 9 is similar to that shown in FIG. 7 , except that the bottom electrode in FIG. 9 is only 240 , wherein 260 and 240 are tungsten electrodes, and 270 can be other electrode material layers.
图10中，顶电极由第一顶电极370、第二顶电极380和第三顶电极390的层叠结构组成，底电极由第一底电极350、第二底电极340和第三底电极330的层叠结构组成，其中370与350为钨电极，330、340、380与390可为其他电极材料层，并且330与390依旧可为钨电极。In FIG. 10 , the top electrode is composed of a stacked 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 the first bottom electrode 350 , the second bottom electrode 340 and the third bottom electrode 330 The layered structure is composed, wherein 370 and 350 are tungsten electrodes, 330, 340, 380 and 390 can be other electrode material layers, and 330 and 390 can still be tungsten electrodes.
图11所示结构与图10类似，不同之处在于图11中的顶电极只有370，其中370与350为钨电极，330、340可为其他电极材料层，并且330可以为钨电极。The structure shown in FIG. 11 is similar to that shown in FIG. 10 , except that the top electrode in FIG. 11 has only 370 , wherein 370 and 350 are tungsten electrodes, 330 and 340 can be other electrode material layers, and 330 can be a tungsten electrode.
图12所示结构与图10类似，不同之处在于图12中的底电极只有240，其中370与350为钨电极，380、390可为其他电极材料，并且390可以为钨电极。The structure shown in FIG. 12 is similar to that shown in FIG. 10 , the difference is that the bottom electrode in FIG. 12 is only 240 , 370 and 350 are tungsten electrodes, 380 and 390 can be other electrode materials, and 390 can be a tungsten electrode.
在图7-12所示的实施例中，压电层的上下两侧均设置有钨电极层，但是本发明不限于此，例如可以仅仅在压电层的一侧设置钨电极层。In the embodiments shown in FIGS. 7-12 , tungsten electrode layers are provided on both the upper and lower sides of the piezoelectric layer, but the present invention is not limited to this, for example, a tungsten electrode layer may be provided only on one side of the piezoelectric layer.
在本发明的上述实施例中，以金属钨形成钨电极或钨电极层，但是本发明不限于此，也可以利用钨合金(即含有金属钨的合金)形成钨电极或钨电极层，这均在本发明的保护范围之内。In the above-mentioned embodiments of the present invention, the tungsten electrode or the tungsten electrode layer is formed of metal tungsten, but the present invention is not limited to this, and the tungsten electrode or the tungsten electrode layer can also be formed by using a tungsten alloy (ie an alloy containing metal tungsten), which is both within the protection scope of the present invention.
需要指出的是，在本发明中，各个数值范围，除了明确指出不包含端点值之外，除了可以为端点值，还可以为各个数值范围的中值，这些均在本发明的保护范围之内。It should be pointed out that, in the present invention, each numerical range, except that it is clearly indicated that it does not include the endpoint value, can be the endpoint value, and can also be the median value of each numerical range, and these are all within the protection scope of the present invention. .
在本发明中，上和下是相对于谐振器的基底的底面而言的，对于一个部件，其靠近该底面的一侧为下侧，远离该底面的一侧为上侧。In the present invention, upper and lower are relative to the bottom surface of the base of the resonator. 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.
在本发明中，内和外是相对于谐振器的有效区域的中心(即有效区域中心)在横向方向或者径向方向上而言的，一个部件的靠近有效区域中心的一侧或一端为内侧或内端，而该部件的远离有效区域中心的一侧或一端为外侧或外端。对于一个参照位置而言，位于该位置的内侧表示在横向方向或径向 方向上处于该位置与有效区域中心之间，位于该位置的外侧表示在横向方向或径向方向上比该位置更远离有效区域中心。In the present invention, inner and outer are relative to the center of the effective area of the resonator (ie, the center of the effective area) in the lateral direction or the radial direction, and one side or one end of a component close to the center of the effective area is the inner side or inner end, and the side or end of the part away from the center of the active area is the outer or outer end. For a reference position, being located inside the position means being between the position and the center of the effective area in the lateral or radial direction, and being located outside of the position means being farther from the position in the lateral or radial direction than the position Effective regional center.
如本领域技术人员能够理解的，根据本发明的体声波谐振器可以用于形成滤波器或电子设备。这里的电子设备，包括但不限于射频前端、滤波放大模块等中间产品，以及手机、WIFI、无人机等终端产品。As can be appreciated by those skilled in the art, BAW resonators according to the present invention may be used to form filters or electronic devices. The electronic equipment here includes but is not limited to intermediate products such as RF front-end, filter and amplifier modules, and terminal products such as mobile phones, WIFI, and drones.
基于以上，本发明提出了如下技术方案：Based on the above, the present invention proposes the following technical solutions:
1、一种体声波谐振器，包括：1. A bulk acoustic wave resonator, comprising:
基底；base;
声学镜；acoustic mirror;
底电极；bottom electrode;
顶电极；和top electrode; and
压电层，设置在底电极与顶电极之间，a piezoelectric layer, arranged between the bottom electrode and the top electrode,
其中：in:
所述压电层为掺杂压电层；且the piezoelectric layer is a doped piezoelectric layer; and
所述顶电极和/或底电极为含有金属钨的钨电极。The top electrode and/or the bottom electrode are tungsten electrodes containing metal tungsten.
2、根据1所述的谐振器，其中：2. The resonator according to 1, wherein:
所述顶电极和/或底电极为由金属钨制成的单层电极或者由钨合金制成的单层电极。The top electrode and/or the bottom electrode is a single-layer electrode made of metal tungsten or a single-layer electrode made of tungsten alloy.
3、根据2所述的谐振器，其中：3. The resonator according to 2, wherein:
所述顶电极和底电极均为钨电极；且The top and bottom electrodes are both tungsten electrodes; and
顶电极或底电极的单层厚度与掺杂压电层的厚度的比值在0.1-1的范围内。The ratio of the monolayer thickness of the top or bottom electrode to the thickness of the doped piezoelectric layer is in the range of 0.1-1.
4、根据2所述的谐振器，其中：4. The resonator according to 2, wherein:
所述顶电极和底电极均为钨电极；The top electrode and the bottom electrode are both tungsten electrodes;
所述底电极的非电极连接端在水平方向上均处于声学镜的边界的外侧而与基底形成热接触。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、根据2所述的谐振器，其中：5. The resonator according to 2, wherein:
所述顶电极和底电极中的一个钨电极，另一个为非钨电极，钨电极的厚度不同于非钨电极的厚度；或者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 that of the non-tungsten electrode; or
所述顶电极和底电极中的一个钨电极，另一个为非钨电极，钨电极的厚 度等于非钨电极的厚度。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 that of the non-tungsten electrode.
6、根据1所述的谐振器，其中：6. The resonator according to 1, wherein:
所述顶电极和/或底电极为叠层电极，所述叠层电极包括叠置的不同材质的至少两层电极层，所述至少两层电极层至少包括一层钨电极层，所述钨电极层为由金属钨制成的电极层或者由钨合金制成的电极层。The top electrode and/or the bottom electrode are stacked electrodes, and the stacked electrode includes at least two stacked electrode layers of different materials, and the at least two electrode layers include at least one tungsten electrode layer. The electrode layer is an electrode layer made of metal tungsten or an electrode layer made of a tungsten alloy.
7、根据6所述的谐振器，其中：7. The resonator according to 6, wherein:
所述叠层电极的邻近压电层的电极层为第一电极层，所述第一电极层为钨电极层。The electrode layer adjacent to the piezoelectric layer of the stacked electrode is a first electrode layer, and the first electrode layer is a tungsten electrode layer.
8、根据7所述的谐振器，其中：8. The resonator according to 7, wherein:
所述顶电极和底电极均为叠层电极。The top electrode and the bottom electrode are both stacked electrodes.
9、根据8所述的谐振器，其中：9. The resonator of 8, wherein:
所述底电极的非电极连接端在水平方向上均处于声学镜的边界的外侧而与基底形成热接触。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.
10、根据7所述的谐振器，其中：10. The resonator according to 7, wherein:
所述顶电极和底电极中的一个叠层电极，另一个为非叠层电极。One of the top electrode and the bottom electrode is a laminated electrode, and the other is a non-laminated electrode.
11、根据1-10中任一项所述的谐振器，其中：11. The resonator of any of 1-10, wherein:
所述压电层为掺钪氮化铝。The piezoelectric layer is scandium-doped aluminum nitride.
12、根据1-10中任一项所述的谐振器，其中：12. The resonator of any of 1-10, wherein:
所述谐振器还包括沿有效区域设置的凸起结构，所述凸起结构的材料为钨。The resonator further includes a protruding structure arranged along the effective area, and the material of the protruding structure is tungsten.
13、一种滤波器，包括根据1-12中任一项所述的体声波谐振器。13. A filter comprising the bulk acoustic wave resonator according to any one of 1-12.
14、一种电子设备，包括根据13所述的滤波器或者根据1-12中任一项所述的谐振器。14. An electronic device comprising the filter according to 13 or the resonator according to any one of 1-12.
尽管已经示出和描述了本发明的实施例，对于本领域的普通技术人员而言，可以理解在不脱离本发明的原理和精神的情况下可以对这些实施例进行变化，本发明的范围由所附权利要求及其等同物限定。Although embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that changes may be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is determined by It is defined by the appended claims and their equivalents.

Claims (14)

  1. 一种体声波谐振器，包括：A bulk acoustic wave resonator, comprising:
    基底；base;
    声学镜；acoustic mirror;
    底电极；bottom electrode;
    顶电极；和top electrode; and
    压电层，设置在底电极与顶电极之间，The piezoelectric layer is arranged between the bottom electrode and the top electrode,
    其中：in:
    所述压电层为掺杂压电层；且the piezoelectric layer is a doped piezoelectric layer; and
    所述顶电极和/或底电极为含有金属钨的钨电极。The top electrode and/or the bottom electrode are tungsten electrodes containing metal tungsten.
  2. 根据权利要求1所述的谐振器，其中：The resonator of claim 1, wherein:
    所述顶电极和/或底电极为由金属钨制成的单层电极或者由钨合金制成的单层电极。The top electrode and/or the bottom electrode is a single-layer electrode made of metal tungsten or a single-layer electrode made of tungsten alloy.
  3. 根据权利要求2所述的谐振器，其中：The resonator of claim 2, wherein:
    所述顶电极和底电极均为钨电极；且The top and bottom electrodes are both tungsten electrodes; and
    顶电极或底电极的单层厚度与掺杂压电层的厚度的比值在0.1-1的范围内。The ratio of the monolayer thickness of the top or bottom electrode to the thickness of the doped piezoelectric layer is in the range of 0.1-1.
  4. 根据权利要求2所述的谐振器，其中：The resonator of claim 2, wherein:
    所述顶电极和底电极均为钨电极；The top electrode and the bottom electrode are both tungsten electrodes;
    所述底电极的非电极连接端在水平方向上均处于声学镜的边界的外侧而与基底形成热接触。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. 根据权利要求2所述的谐振器，其中：The resonator of claim 2, wherein:
    所述顶电极和底电极中的一个钨电极，另一个为非钨电极，钨电极的厚度不同于非钨电极的厚度；或者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 that of the non-tungsten electrode; or
    所述顶电极和底电极中的一个钨电极，另一个为非钨电极，钨电极的厚度等于非钨电极的厚度。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 equal to the thickness of the non-tungsten electrode.
  6. 根据权利要求1所述的谐振器，其中：The resonator of claim 1, wherein:
    所述顶电极和/或底电极为叠层电极，所述叠层电极包括叠置的不同材质的至少两层电极层，所述至少两层电极层至少包括一层钨电极层，所述钨电 极层为由金属钨制成的电极层或者由钨合金制成的电极层。The top electrode and/or the bottom electrode are stacked electrodes, the stacked electrode includes at least two stacked electrode layers of different materials, the at least two electrode layers include at least one tungsten electrode layer, and the tungsten electrode The electrode layer is an electrode layer made of metal tungsten or an electrode layer made of a tungsten alloy.
  7. 根据权利要求6所述的谐振器，其中：The resonator of claim 6, wherein:
    所述叠层电极的邻近压电层的电极层为第一电极层，所述第一电极层为钨电极层。The electrode layer adjacent to the piezoelectric layer of the stacked electrode is a first electrode layer, and the first electrode layer is a tungsten electrode layer.
  8. 根据权利要求7所述的谐振器，其中：The resonator of claim 7, wherein:
    所述顶电极和底电极均为叠层电极。The top electrode and the bottom electrode are both stacked electrodes.
  9. 根据权利要求8所述的谐振器，其中：The resonator of claim 8, wherein:
    所述底电极的非电极连接端在水平方向上均处于声学镜的边界的外侧而与基底形成热接触。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.
  10. 根据权利要求7所述的谐振器，其中：The resonator of claim 7, wherein:
    所述顶电极和底电极中的一个叠层电极，另一个为非叠层电极。One of the top electrode and the bottom electrode is a laminated electrode, and the other is a non-laminated electrode.
  11. 根据权利要求1-10中任一项所述的谐振器，其中：The resonator of any of claims 1-10, wherein:
    所述压电层为掺钪氮化铝。The piezoelectric layer is scandium-doped aluminum nitride.
  12. 根据权利要求1-10中任一项所述的谐振器，其中：The resonator of any of claims 1-10, wherein:
    所述谐振器还包括沿有效区域设置的凸起结构，所述凸起结构的材料为钨。The resonator further includes a protruding structure arranged along the effective area, and the material of the protruding structure is tungsten.
  13. 一种滤波器，包括根据权利要求1-12中任一项所述的体声波谐振器。A filter comprising a bulk acoustic wave resonator according to any one of claims 1-12.
  14. 一种电子设备，包括根据权利要求13所述的滤波器或者根据权利要求1-12中任一项所述的谐振器。An electronic device comprising a filter according to claim 13 or a resonator according to any one of claims 1-12.
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CN102931941A (en) * 2012-10-29 2013-02-13 天津理工大学 FBAR (film bulk acoustic resonator) substrate and preparation method thereof
US20150280100A1 (en) * 2014-03-31 2015-10-01 Avago Technologies General Ip (Singapore) Pte. Ltd. Acoustic resonator comprising acoustic redistribution layers
CN110868183A (en) * 2019-04-23 2020-03-06 中国电子科技集团公司第十三研究所 Resonator and filter
CN110868185A (en) * 2019-04-23 2020-03-06 中国电子科技集团公司第十三研究所 Bulk acoustic wave resonator and semiconductor device
CN111010138A (en) * 2019-12-05 2020-04-14 武汉大学 High Q bulk acoustic wave resonator

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102931941A (en) * 2012-10-29 2013-02-13 天津理工大学 FBAR (film bulk acoustic resonator) substrate and preparation method thereof
US20150280100A1 (en) * 2014-03-31 2015-10-01 Avago Technologies General Ip (Singapore) Pte. Ltd. Acoustic resonator comprising acoustic redistribution layers
CN110868183A (en) * 2019-04-23 2020-03-06 中国电子科技集团公司第十三研究所 Resonator and filter
CN110868185A (en) * 2019-04-23 2020-03-06 中国电子科技集团公司第十三研究所 Bulk acoustic wave resonator and semiconductor device
CN111010138A (en) * 2019-12-05 2020-04-14 武汉大学 High Q bulk acoustic wave resonator

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