Bulk acoustic wave resonator device, radio frequency filter, radio frequency module, and radio frequency device

Abstract

To provide a bulk acoustic wave resonator having an improved quality factor Q.SOLUTION: A bulk acoustic wave resonator 100 includes: a piezoelectric material layer 130; a first metal layer 110 disposed on an upper surface of the piezoelectric material layer 130; a second metal layer 120 disposed on a lower surface of the piezoelectric material layer 130; and a laterally distributed raised frame including a first raised frame 140 disposed on an upper surface of the first metal layer 110 and having an inner raised frame section with a tapered portion and a non-tapered portion and an outer raised frame section and a second raised frame 150 disposed beneath the first metal layer 110 and the outer raised frame section, but not beneath the inner raised frame section. The inner raised frame section is laterally disposed from a central active region 160 of the bulk acoustic wave resonator 100 by a first distance, and the outer raised frame section is laterally disposed from the central active region 160 by a second distance greater than the first distance.SELECTED DRAWING: Figure 1A

Description

Technical Field

[0001] The present disclosure generally relates to bulk acoustic wave resonators.

Background Art

[0002] A bulk acoustic wave resonator is a device having a piezoelectric material between two electrodes. When an electromagnetic signal is applied to one of the electrodes, an elastic wave is generated in the piezoelectric material and propagates to the other electrode.

[0003] Depending on the thickness of the piezoelectric material, resonance of such an elastic wave is established, and an electromagnetic signal having a frequency corresponding to the resonant elastic wave is generated at the other electrode. That is, such a bulk acoustic wave resonator can be utilized to provide a filtering function for an electromagnetic signal such as a radio frequency (RF) signal.

[0004] In many applications, the piezoelectric material between the electrodes is relatively thin and is implemented as a film. Thus, a bulk acoustic wave resonator may be referred to as a thin film bulk acoustic wave resonator (TFBAR) or a film bulk acoustic wave resonator (FBAR).

Summary of the Invention

[0005] According to one aspect disclosed herein, a bulk acoustic wave resonator device is provided. The bulk elastic wave resonator includes a piezoelectric material layer having an upper and lower surface, a first metal layer having a lower and upper surface disposed on the upper surface of the piezoelectric material layer, a second metal layer having an upper and lower surface disposed on the lower surface of the piezoelectric material layer, a first raised frame disposed on the upper surface of the first metal layer and having an inner raised frame section and an outer raised frame section with tapered and non-tapered portions, and a lateral dispersion raised frame including a second raised frame disposed below the first metal layer and the outer raised frame section but not below the inner raised frame section, wherein the inner raised frame section of the first raised frame is positioned laterally at a first distance from the central effective region of the bulk elastic wave resonator device, and the outer raised frame section of the first raised frame is positioned laterally at a second distance from the central effective region of the bulk elastic wave resonator device, the second distance being greater than the first distance, and the lateral dispersion raised frame is configured to improve the reflection of transverse mode waves and reduce the conversion from major mode waves to transverse mode waves.

[0006] In some embodiments, the first raised frame is formed from metal.

[0007] In some embodiments, the second raised frame is formed from an oxide.

[0008] In some embodiments, the outer raised frame section of the first raised frame has a width and a substantially uniform thickness over that width.

[0009] In some embodiments, the second raised frame includes an inner tapered portion and an outer non-tapered portion.

[0010] In some embodiments, the inner tapered portion of the second raised frame has a taper angle of 10° to 60°.

[0011] In some embodiments, the outer non-tapered portion of the second raised frame has a width and a substantially uniform thickness over that width.

[0012] In some embodiments, the tapered portion of the inner raised frame section of the first raised frame has a taper angle of 5° to 45°.

[0013] In some embodiments, the bulk acoustic wave resonator device further includes a dielectric layer positioned on the upper surface of the first metal layer, which defines a recessed frame region surrounding the central effective region.

[0014] In some embodiments, the bulk acoustic wave resonator device does not include a recessed frame region.

[0015] In some embodiments, the tapered portion of the inner raised frame section of the first raised frame has a narrower width than the width of the non-tapered portion of the inner raised frame section of the first raised frame.

[0016] In some embodiments, the tapered portion of the inner raised frame section of the first raised frame has a wider width than the non-tapered portion of the inner raised frame section of the first raised frame.

[0017] In some embodiments, the second raised frame has an upper surface that contacts the lower surface of the first metal layer.

[0018] In some embodiments, the second raised frame has a lower surface that contacts the upper surface of the second metal layer.

[0019] In some embodiments, the second raised frame has an upper surface that contacts the piezoelectric material layer.

[0020] In some embodiments, the second raised frame has an upper surface that contacts the piezoelectric material layer.

[0021] In some embodiments, the second raised frame has a lower surface that contacts the piezoelectric material layer, and the second raised frame divides the piezoelectric material layer into an upper piezoelectric material layer and a lower piezoelectric material layer.

[0022] In some embodiments, the first raised frame is formed of a material having an acoustic impedance higher than that of the material of which the second raised frame is formed, and an acoustic impedance higher than that of the material of which the piezoelectric material layer is formed.

[0023] In some embodiments, the first raised frame is formed of a material having an acoustic impedance lower than that of the material of which the second raised frame is formed, and an acoustic impedance lower than that of the material of which the piezoelectric material layer is formed.

[0024] In some embodiments, the bulk acoustic wave resonator device is a thin film bulk acoustic wave resonator device defined below the second metal layer.

[0025] In some embodiments, the bulk acoustic wave resonator device is a solidly mounted resonator including a Bragg reflector disposed under the second metal layer.

[0026] In some embodiments, the tapered portion of the inner raised frame section of the first raised frame has a linear taper.

[0027] In some embodiments, the tapered portion of the inner raised frame section of the first raised frame has a concave taper.

[0028] In some embodiments, the tapered portion of the inner raised frame section of the first raised frame has a convex taper.

[0029] In some embodiments, the second raised frame includes an inner tapered portion having a linear taper.

[0030] In some embodiments, the second raised frame includes an inner tapered portion having a concave taper.

[0031] In some embodiments, the second raised frame includes an inner tapered portion having a convex taper.

[0032] In some embodiments, a radio frequency filter includes the bulk acoustic wave resonator device described above.

[0033] The radio frequency filter may be included in a radio frequency module.

[0034] The radio frequency module may be included in a radio frequency device.

Brief Description of the Drawings

[0035] Embodiments of the present disclosure are described below through non-limiting examples with reference to the accompanying drawings.

[0036] [Figure 1A] FIG. 28 is a cross-sectional view of an example of a FBAR device including one or more tapered raised frames. [Figure 1B] FIG. 31 is an enlarged cross-sectional view of the first raised frame of the FBAR device of FIG. 1A. [Figure 1C] FIG. 34 is an enlarged cross-sectional view of the second raised frame of the FBAR device of FIG. 1A. [Figure 2] FIG. 37 is a cross-sectional view of another example of a FBAR device including one or more tapered raised frames. [Figure 3] FIG. 40 is a cross-sectional view of another example of a FBAR device including one or more tapered raised frames. [Figure 4] FIG. 43 is a cross-sectional view of another example of a FBAR device including one or more tapered raised frames. [Figure 5] FIG. 46 is a cross-sectional view of another example of a FBAR device including one or more tapered raised frames. [Figure 6] FIG. 49 is a cross-sectional view of another example of a FBAR device including one or more tapered raised frames. [Figure 7]Multiple examples of cross-sectional profiles of the raised frame portion according to a predetermined embodiment are shown. [Figure 8] This shows the simulation results of the effects of raised frame thickness and taper angle on the quality factor in FBAR devices. [Figure 9] This shows the simulation results of the effect of raised frame thickness and raised frame width on the quality factor in FBAR devices. [Figure 10] This is a cross-sectional view of an example of a solid-mount resonator (SMR). [Figure 11A] This is a cross-sectional view of an example of an SMR (Surface Modulated Reinforcement) including one or more tapered ridge frames. [Figure 11B] This is a cross-sectional view of another example of an SMR containing one or more tapered ridge frames. [Figure 11C] This is a cross-sectional view of another example of an SMR containing one or more tapered ridge frames. [Figure 11D] This is a cross-sectional view of another example of an SMR containing one or more tapered ridge frames. [Figure 11E] This is a cross-sectional view of another example of an SMR containing one or more tapered ridge frames. [Figure 11F] This is a cross-sectional view of another example of an SMR containing one or more tapered ridge frames. [Figure 12] This is a block diagram of an example of a filter module that may include one or more elastic wave elements relating to multiple aspects of this disclosure. [Figure 13] This is a block diagram of an example of a front-end module that may include one or more filter modules relating to multiple aspects of this disclosure. [Figure 14] Figure 13 is a block diagram of an example of a wireless device including a front-end module. [Modes for carrying out the invention]

[0037] The following detailed description of a given embodiment presents various descriptions of a particular embodiment. However, the innovation described herein can be embodied in numerous different forms defined and covered, for example, by the claims. In this specification, the same reference numeral refers to drawings showing identical or functionally similar elements. It should be understood that the elements shown in the drawings are not necessarily to scale. It should also be understood that a given embodiment may include more elements than shown in the drawings, and / or subsets of the elements shown in the drawings. Furthermore, some embodiments may also include any suitable combination of features from two or more drawings.

[0038] The headings provided herein, if any, are for convenience only and do not necessarily affect the scope or meaning of the claimed invention.

[0039] This disclosure describes various examples relating to thin-film bulk acoustic wave resonators (FBARs) and related devices having an improved quality factor Q. For example, the FBARs and related devices described herein may have increased mode reflections and reduced mode conversion. Although such examples are described in the context of FBARs, one or more features of this disclosure can also be implemented in other types of resonators that are similar to FBARs but referred to in other terms.

[0040] According to certain aspects, an FBAR may include a raised frame that improves the quality factor Q above the resonant frequency fs. Generally, in an FBAR, leakage of transversely propagated modes outside the effective region can cause a decrease in the quality factor Q. In addition, mode conversion from the dominant mode to the transverse mode can also cause a decrease in the quality factor Q. The raised frame can improve the quality factor Q by acting as a reflector that reflects transverse modes back into the effective region. However, having only one raised frame is not sufficient to reflect all transverse modes. To enhance reflection and achieve maximum mode reflection, multiple reflectors, such as two or more raised frames, can be formed, for example, by forming different mismatched acoustic impedance interfaces. However, forming multiple reflectors can result in a certain number of discontinuity boundaries that can increase mode conversion.

[0041] According to a given aspect, an FBAR is provided that includes one or more raised frames, including tapered and non-tapered regions. Such raised frames are efficient at suppressing transverse mode leakage. For example, a raised frame including tapered and non-tapered regions can act as a multiple reflector that can improve reflection efficiency. As another example, a raised frame including tapered and non-tapered regions can reduce mode conversion from the dominant mode to other modes that would cause discontinuous boundaries. As mentioned above, in addition to mode reflection, mode conversion can also affect the quality factor Q. A raised frame including tapered and non-tapered regions can create a pseudo-continuous boundary and suppress mode conversion from the dominant mode to other modes. In some embodiments, due to the pseudo-continuous boundary and multiple reflection, the quality factor Q can be significantly improved at low taper angles.

[0042] Figure 1A shows a side view of the FBAR device 100, which includes a lateral dispersion raised frame. This raised frame includes an inner reflector 105 and an outer reflector 115. The FBAR device 100 may include a first metal layer 110, a second metal layer 120, and a piezoelectric layer 130 located between the first metal layer 110 and the second metal layer 120. A resonator can be formed by placing the piezoelectric layer 130 between the first metal layer 110 and the second metal layer 120. In some embodiments, the portion of the piezoelectric layer 130 that overlaps with the first metal layer 110 and the second metal layer 120 is referred to as the “resonator”. In some embodiments, the metal layers 110 and 120 are referred to as “electrodes”. A radio frequency (RF) signal is applied to one of the metal layers 110 or 120, causing the generation of elastic waves in the piezoelectric layer 130. The elastic wave propagates through the piezoelectric layer 130 and is converted into an RF signal in the other metal layer 110, 120. In this way, the FBAR device 100 can provide a filtering function. In the FBAR device 100, the elastic wave can propagate in the vertical direction (for example, perpendicular to the metal layers 110, 120 and the piezoelectric layer 130). For example, the vertical direction may be the Z direction. Some elastic waves can propagate in the horizontal direction (for example, parallel to the metal layers 110, 120 and the piezoelectric layer 130). For example, the horizontal direction may be the X direction, the Y direction, or a combination thereof.

[0043] The FBAR device 100 may include one or more raised frames ("RaF"). In the example in Figure 1A, the FBAR device 100 includes a first raised frame 140 and a second raised frame 150. For example, the first raised frame 140 may be located on top of the second metal layer 120, and the second raised frame 150 may be located below the second metal layer 120, between the second metal layer 120 and the piezoelectric layer 130. Each raised frame may include a tapered portion and a non-tapered portion, or a tapered end and a non-tapered portion or a non-tapered end. As shown in the example in Figure 1A, the first raised frame 140 and the second raised frame 150 may each include a tapered region and a non-tapered region on each side of the FBAR device.

[0044] Figure 1B is an enlarged view of the first raised frame 140. This shows the inner reflector region 105, the outer reflector region 115, the tapered region 105T of the inner reflector region 105, and the non-tapered region 105NT of the inner reflector region 105 of the first raised frame 140. Figure 1C is an enlarged view of the second raised frame 150. This shows the tapered region 150T and the non-tapered region 150NT of the second raised frame 150. In the embodiment of Figure 1A, the second raised frame 150 does not include the inner and outer reflector regions and exists only below the outer reflector region 115 of the first raised frame 140.

[0045] The non-tapered regions of the first raised frame 140 and the second raised frame 150 may have substantially constant height or thickness over their horizontal ranges. There may be slight deviations in the thickness of the non-tapered regions of the first raised frame 140 and the second raised frame 150 so that the upper or lower surface of the first raised frame 140 and the second raised frame 150 changes its slope to conform to the adjacent upper or lower material layer, but the non-tapered regions of the first raised frame 140 and the second raised frame 150 may still be considered to have substantially constant height or thickness over their horizontal ranges. As shown in Figures 1A to 1C, the non-tapered regions of the first raised frame 140 and the second raised frame 150 may be adjacent to and close to the non-tapered regions of the first raised frame 140 and the second raised frame 150.

[0046] The tapered region of the raised frame may have a taper angle defined, for example, by angle α with respect to the horizontal direction. Angle α may be referred to as the “taper angle”. In some embodiments, angle α may be less than 90°. In some embodiments, α may be between 5° and 45°. In the embodiment of Figure 1A, angle α refers to the taper angle of the tapered region 105T of the first raised frame 140. The symbol β is used to refer to the taper angle of the tapered portion 150T of the second raised frame 150. Angle β may be less than 90°, or between 10° and 60°. Angle α and β may be the same or different in different embodiments.

[0047] In a given embodiment, the tapered region of the raised frame may have a triangular shape. In another embodiment, the tapered region of the raised frame may have a different polygonal shape. In some embodiments, the first raised frame 140 and the second raised frame 150 may have overlapping regions. For example, the tapered region 105T of the first raised frame 140 and the tapered region 150T of the second raised frame 150 may overlap at least partially, for example, in the horizontal direction. The metal layers 110, 120 and the piezoelectric layer 130 may follow the contour or shape of the first raised frame 140 and / or the second raised frame 150. Therefore, the metal layers 110, 120 and the piezoelectric layer 130 may include portions parallel to the horizontal direction and portions that form a certain angle with respect to the horizontal direction.

[0048] The raised frame may be made from any suitable material. In some embodiments, the raised frame may be made from the same or identical material as the second metal layer 120 and / or the first metal layer 110. For example, the raised frame may be made from a heavy material. In a given embodiment, the raised frame may be made from a low acoustic impedance material. For example, the raised frame may be made from silicon dioxide, silicon nitride, etc. The raised frame may be made from any low-density material. For example, in the embodiment of Figure 1A, the first raised frame may be formed from metal and the second raised frame may be formed from silicon dioxide. The first raised frame 140 may be made from a material with a higher acoustic impedance than the material on which the second raised frame 150 is formed and a higher acoustic impedance than the material of the piezoelectric layer 130. The second raised frame 150 may be made from a material with a lower acoustic impedance than the material on which the first raised frame 140 is formed and a lower acoustic impedance than the material of the piezoelectric layer 130. The tapered region of the raised frame may be formed during the manufacturing process of the FBAR device (for example, by a deposition process).

[0049] In the example shown in Figure 1A, the FBAR device 100 is shown to include two raised frames for illustrative purposes, but the number of raised frames included in the FBAR device 100 may vary depending on the embodiment. For example, in some embodiments, the FBAR device 100 may include one raised frame or more than two raised frames. One or more raised frames can be arranged in various configurations. One or more raised frames can be arranged at various positions along the vertical direction (for example, perpendicular to the metal layers 110, 120 and the piezoelectric layer 130). For example, one or more raised frames may be arranged above or below the first metal layer 110, above or below the second metal layer 120, between the first metal layer 110 and the second metal layer 120, or in any combination thereof. Various examples of raised frame configurations are described below.

[0050] The FBAR device 100 may include, for example, an effective region 160 between the tapered regions 105T of the inner reflector region 105 of the first raised frame 140 on each side of the FBAR device 100. The primary mode wave can propagate through the effective region 160. For example, the effective region 160 may be located in a preferred region from which the primary mode wave can propagate. Viewed from a top-down perspective, the effective region 160 may have a cylindrical, rectangular, or other suitable shape. In some embodiments, the FBAR device 100 may include a passivation layer 180 above the first raised frame 140 and the second metal layer 120. The passivation layer 180 may be located at the top of the first raised frame 140 and at the top of the exposed portion of the second metal layer 120. The exposed portion of the second metal layer 120 may be the portion not covered by the first raised frame 140. In some embodiments, the FBAR device 100 may also include a recessed frame (ReF) region 185 defined by a thinned portion of the passivation layer 180 and defining the outer boundary of the effective region 160. The passivation layer 180 is thinner in the recessed frame region 185 than in the effective region 160. The thickness of the passivation layer 180 in the recessed frame region 185 may be the same as or equal to the thickness of the passivation layer 180 on the first raised frame 140 in the inner reflector region 105 and / or outer reflector region 115. In some embodiments, the recessed frame region 185 may be an adjacent ring structure surrounding the effective region 160. The passivation layer 180 may be formed from a dielectric material, such as silicon dioxide or silicon nitride. In some embodiments, the FBAR device 100 may include a substrate 170 below the first metal layer 110 and may include an air cavity 190. In some embodiments, the distal end of the first metal layer 110 may be separated from the adjacent region of the substrate 170 by a gap 110G.

[0051] A raised frame including tapered and non-tapered regions can increase modal reflection and decrease modal conversion by creating a pseudo-continuous boundary. For example, a pseudo-continuous boundary can act as a multiple reflector that increases modal reflection. A pseudo-continuous boundary can also suppress modal conversion. In this embodiment, an FBAR device including one or more raised frames having tapered and non-tapered regions may have an improved quality factor Q. In some embodiments, a low taper angle for a gradient raised frame may be effective in increasing modal reflection and decreasing modal conversion. For example, the taper angle for the tapered region of the raised frame may be less than 45°, less than 30°, 10° to 60°, or 5° to 45°, as described above. The taper angle can be selected to maximize the reduction of modal reflection and modal conversion.

[0052] Figure 2 shows a side view of the FBAR device 200. This is similar to the FBAR device 100 in Figure 1, but differs in that the FBAR device 200 does not include the passivation layer 180. In the embodiment of Figure 2, the outer boundary of the effective region 160 is defined by the inner edge of the inner reflector 105 of the first raised frame 140.

[0053] Figure 3 shows a side view of the FBAR device 300. This is similar to the FBAR device 200 in Figure 2, but differs in that the FBAR device 300 includes a tapered region 105T of the inner reflector portion 105 of the first raised frame 140 that is wider than the non-tapered region 105NT of the inner reflector portion 105 of the first raised frame 140. This is in contrast to the FBAR devices 100 and 200 in Figures 1 and 2, respectively, in which the non-tapered region 105NT of the inner reflector portion 105 of the first raised frame 140 is wider than the tapered region 105T of the inner reflector portion 105 of the first raised frame 140. In other embodiments, the non-tapered region 105NT of the inner reflector portion 105 of the first raised frame 140 may be the same size as, or substantially the same size as, the tapered region 105T of the inner reflector portion 105 of the first raised frame 140. In some embodiments, the FBAR device 300 may include a passivation layer 180 and a recessed frame region 185 similar to those shown in Figure 1 for the FBAR device 100.

[0054] Figure 4 shows a side view of the FBAR device 400. This is similar to the FBAR device 300 in Figure 3, except that the tapered region of the first raised frame 140 of the FBAR device 400 extends so as to completely pass through the inner reflector region 105 and enter the outer reflector region 115. That is, the inner reflector region 105 may be considered to consist entirely of a tapered region 105T. The outer reflector region 115 may be considered to be divided into an inner tapered region 115T and an outer non-tapered region 115NT adjacent to the tapered region 115T. In some embodiments, the FBAR device 400 may include a passivation layer 180 and a recessed frame region 185 similar to those shown in Figure 1 for the FBAR device 100.

[0055] Figure 5 shows a side view of the FBAR device 500. This is similar to the FBAR device 100 in Figure 1, but in the FBAR device 500, the second raised frame 150 is partially positioned between the first metal layer 110 and the piezoelectric layer 130, and beneath the piezoelectric layer 130. The second raised frame 150 may be partially positioned between the substrate 170 and the piezoelectric layer 130, and beneath the piezoelectric layer 130. The second raised frame 150 may be partially positioned between the air cavity 190 and the piezoelectric layer 130, and beneath the piezoelectric layer 130.

[0056] Figure 6 shows a side view of the FBAR device 600. This is similar to the FBAR device 500 in Figure 5, but in the FBAR device 600, the second raised frame 150 is located inside the piezoelectric layer 130, rather than below it. The second raised frame 150 can be considered to divide the piezoelectric layer into an upper piezoelectric layer 130U and a lower piezoelectric layer 130L.

[0057] In the embodiments described above, the width of the tapered region of the raised frame increases monotonically or linearly as the horizontal distance moves away from the central effective region 160 of the FBAR device. In other embodiments, the tapered region of the raised frame may exhibit a nonlinear gradient, for example, as shown in Figure 7. For example, the nonlinear gradient may include a convex portion 610, a concave portion 620, or any combination thereof. The example in Figure 7 is given for illustrative purposes only, and many other modifications of the nonlinear gradient raised frame portion are possible.

[0058] Figure 8 shows the simulation results of the effect on the quality factor Q of the thickness of the non-tapered portion 115NT of the outer reflector portion 115 (MRaT parameter in the chart in Figure 8) and the taper angle α of the tapered portion 105T of the inner reflector portion 105 of the first raised frame 140 at the anti-resonant frequency in an example of an FBAR. In the simulated FBAR, the width of the raised frame was 2 μm, the thickness of the passivation layer in the effective region was 150 nm, the thickness of the first metal layer was 430 nm, the thickness of the piezoelectric layer was 600 nm, the thickness of the second metal layer was 440 nm, the thickness of the non-tapered portion of the second raised frame was 100 nm, and the width of the air cavity was 120 μm. The results shown in Figure 8 indicate that the quality factor can generally increase with increasing frame thickness and decreasing taper angle, but can periodically rise or fall when any of these parameters increase or decrease.

[0059] Figure 9 shows the simulation results of the effect on the quality factor Q of the thickness of the non-tapered portion 115NT of the outer reflector portion 115 (MRaT parameter in the chart in Figure 9) and the width of the inner reflector region of the first raised frame (MRaW parameter in the chart in Figure 9) at the anti-resonant frequency of the same FBAR used to simulate the results shown in Figure 8. The results in Figure 9 show that a high Q is found for an FBAR with an inner reflector region width of approximately 1 μm of the first raised frame and a first raised frame thickness of approximately 100 nm. Some periodicity in the Q value can be observed as the inner reflector region width of the first raised frame changes.

[0060] Multiple aspects and embodiments of the raised frame structure disclosed herein may be used not only for the FBAR device described above but also for other forms of bulk acoustic wave resonators, such as solid-mount resonators (SMRs). As shown in Figure 10, an example of an SMR includes a piezoelectric layer formed from, for example, aluminum nitride or other suitable piezoelectric material, an upper electrode (layer of metal 2 in Figure 10) positioned on the upper surface of the piezoelectric layer, and a lower electrode (layer of metal 1 in Figure 10) positioned on the lower surface of the piezoelectric layer. The piezoelectric layer and the upper and lower electrodes may be arranged in a Bragg reflector formed from alternating layers of a first material having high acoustic impedance, such as tungsten, and a second material having low acoustic impedance, such as SiO2. The Bragg reflector may be mounted on a substrate, such as a silicon substrate. The SMR may have a raised frame including a layer of dielectric material, such as SiO2 (the raised frame layer shown in Figure 10), positioned between the lower surface of the upper electrode and the piezoelectric material in the raised frame domain region of the resonator.

[0061] Figure 11A shows how the raised frame structure shown in the FBAR of Figure 1A can be used in SMR. Figure 11B shows how the raised frame structure shown in the FBAR of Figure 2 can be used in SMR. Figure 11C shows how the raised frame structure shown in the FBAR of Figure 3 can be used in SMR. Figure 11D shows how the raised frame structure shown in the FBAR of Figure 4 can be used in SMR. Figure 11E shows how the raised frame structure shown in the FBAR of Figure 5 can be used in SMR. Figure 11F shows how the raised frame structure shown in the FBAR of Figure 6 can be used in SMR.

[0062] The elastic wave devices described herein can be implemented in various package modules. Several exemplary package modules in which any suitable principles and advantages of the packaged elastic wave devices described herein can be implemented are described below. Figures 12, 13, and 14 are schematic block diagrams of exemplary package modules and devices according to a given embodiment.

[0063] As described above, multiple embodiments of the disclosed BAW resonator can be configured, for example, as a filter, or configured for use in a filter. Ultimately, a BAW filter using one or more BAW resonator elements can be incorporated into a module used in an electronic device, such as a wireless communication device, or packaged as such a module. Figure 12 is a block diagram showing an example of a module 700 including a BAW filter 710. The BAW filter 710 may be mounted on one or more dies 720 including one or more connection pads 722. For example, the BAW filter 710 may include a connection pad 722 corresponding to an input contact for the BAW filter and other connection pads 722 corresponding to an output contact for the BAW filter. The package module 700 includes a packaging substrate 730 configured to receive multiple components, including dies 720. Multiple connection pads 732 can be arranged on the packaging substrate 730, and various connection pads 722 of the BAW filter die 720 can be connected to connection pads 732 on the packaging substrate 730 via electrical connectors 734. The electrical connector 734 may be, for example, a solder bump or wire bond, to allow the passage of various signals to and from the BAW filter 710. The module 700 may further optionally include other circuit dies 740 known to those skilled in the art of semiconductor manufacturing in view of this disclosure, such as one or more additional filters, amplifiers, pre-filters, modulators, demodulators, downconverters, etc. In some embodiments, the module 700 may also include one or more package structures, for example, to protect the module 700 and to facilitate handling of the module 700. Such package structures may include an overmolding formed on a packaging substrate 730 to dimensions that substantially encapsulate various circuits and components.

[0064] Various examples and embodiments of the BAW filter 710 can be used in a wide variety of electronic devices. For example, the BAW filter 710 can be used in an antenna duplexer, which can itself be incorporated into various electronic devices such as RF front-end modules and communication devices.

[0065] Referring to Figure 13, a block diagram of an example of a front-end module 800 is shown. The front-end module 500 may be used in an electronic device such as a wireless communication device (e.g., a mobile phone). The front-end module 800 includes an antenna duplexer 810 having a common node 802, an input node 804, and an output node 806. An antenna 910 is connected to the common node 802.

[0066] The antenna duplexer 810 may include one or more transmit filters 812 connected between the input node 804 and the common node 802, and one or more receive filters 814 connected between the common node 802 and the output node 806. The passband of the transmit filters is different from that of the receive filters. Multiple examples of the BAW filter 710 can be used to form the transmit filters 812 and / or receive filters 814. An inductor or other matching component 820 may be connected to the common node 802.

[0067] The front-end module 800 further includes a transmitter circuit 832 connected to the input node 804 of the duplexer 810 and a receiver circuit 834 connected to the output node 806 of the duplexer 810. The transmitter circuit 832 generates a signal for transmission via the antenna 910, and the receiver circuit 834 can process the signal received via the antenna 910. In some embodiments, the receiver circuit and the transmitter circuit may be implemented as separate components as shown in Figure 13, but in other embodiments, these components may be integrated into a common transceiver circuit or module. As will be apparent to those skilled in the art, the front-end module 800 may include, but is not limited to, switches, electromagnetic couplers, amplifiers, processors, and other components not shown in Figure 13.

[0068] Figure 14 is a block diagram of an example of a wireless device 900 including the antenna duplexer 810 shown in Figure 13. The wireless device 900 may be a cellular telephone, smartphone, tablet, modem, communication network, or any other portable or non-portable device configured for voice or data communication. The wireless device 900 can receive and transmit signals from the antenna 910. The wireless device includes one embodiment of a front-end module 800 similar to that described above with reference to Figure 13. The front-end module 800 includes the duplexer 810 described above. In the example shown in Figure 14, the front-end module 800 further includes an antenna switch 840 which may be configured to switch between different frequency bands or modes, such as a transmit mode and a receive mode. In the example shown in Figure 14, the antenna switch 840 is located between the duplexer 810 and the antenna 910, but in other examples, the duplexer 810 may be located between the antenna switch 840 and the antenna 910. In other cases, the antenna switch 840 and the duplexer 810 may be integrated into a single component.

[0069] The front-end module 800 includes a transceiver 830 configured to generate a signal for transmission or to process a received signal. The transceiver 830 may include a transmitter circuit 832 connected to the input node 804 of the duplexer 810 and a receiver circuit 834 connected to the output node 806 of the duplexer 810, as shown in the example in Figure 13.

[0070] The signal generated for transmission by the transmitter circuit 832 is received by the power amplifier (PA) module 850. The PA module 850 amplifies the generated signal from the transceiver 830. The power amplifier module 850 may include one or more power amplifiers. The power amplifier module 850 can be used to amplify a wide variety of RF or other frequency band transmission signals. For example, the power amplifier module 850 can receive an enable signal that can be used to pulse the output of the power amplifier. This assists in the transmission of wireless local area network (WLAN) signals or any other suitable pulsed signals. The power amplifier module 850 can be configured to amplify any of the various types of signals, including, for example, Global System for Mobile (GSM®) signals, code division multiple access (CDMA) signals, W-CDMA signals, Long-Term Evolution (LTE) signals, or edge signals. In a predetermined embodiment, the power amplifier module 850 and related components including switches can be fabricated, for example, on a gallium arsenide (GaAs) substrate using high electron mobility transistors (pHEMT) or insulated-gate bipolar transistors (BiFETs), or on a silicon substrate using complementary metal-oxide-semiconductor (CMOS) field-effect transistors.

[0071] Still referring to Figure 14, the front-end module 800 may further include a low-noise amplifier module 860 that amplifies the received signal from the antenna 910 and provides the amplified signal to the receiver circuit 834 of the transceiver 830.

[0072] The wireless device 900 in Figure 14 further includes a power management subsystem 920 connected to the transceiver 830 to manage power for the operation of the wireless device 900. The power management system 920 can also control the operation of the baseband subsystem 930 and various other components of the wireless device 900. The power management system 920 may include, or be connected to, a battery (not shown) that supplies power to various components of the wireless device 900. The power management system 920 may further include, for example, one or more processors or controllers that can control the transmission of signals. In one embodiment, the baseband subsystem 930 is connected to a user interface 940 to facilitate various inputs and outputs of voice and / or data given to and received from the user. The baseband subsystem 930 is also connected to a memory 950 configured to store data and / or instructions in order to facilitate the operation of the wireless device and / or to store information for the user. Any of the embodiments described above can be implemented in relation to a portable device such as a cellular handset. The principles and benefits of these embodiments can be used for any system or device, such as any uplink wireless communication device, that can benefit from any of the embodiments described herein. The teachings herein are applicable to a variety of systems. Although this disclosure includes some exemplary embodiments, the teachings described herein can be applied to a variety of structures. Any of the principles and benefits described herein can be implemented in relation to RF circuits configured to process signals in the range of about 30 kHz to 300 GHz, such as in the range of about 450 MHz to 6 GHz.

[0073] Multiple aspects of this disclosure can be implemented in various electronic devices. Examples of electronic devices may include, but are not limited to, consumer electronic products, components of consumer electronic products such as packaged radio frequency modules, uplink wireless communication devices, wireless communication infrastructure, and electronic test equipment. Examples of electronic devices may include, but are not limited to, portable telephones such as smartphones, wearable computing devices such as smartwatches or earpieces, telephones, televisions, computer monitors, computers, modems, handheld computers, laptop computers, tablet computers, microwave ovens, refrigerators, automotive electronic systems such as automotive electronic systems, stereo systems, digital music players, radios, cameras such as digital cameras, portable memory chips, washing machines, dryers, washer / dryer machines, photocopiers, facsimile machines, scanners, multifunction peripheral devices, wristwatches, and clocks. Furthermore, electronic devices may include unfinished products.

[0074] Unless the context explicitly requires otherwise, throughout the specification and claims, terms such as “includes,” “equip,” and so on should be interpreted in a comprehensive sense, the opposite of an exclusive or exhaustive sense, i.e., “includes but not limited to.” The term “combined,” as used herein, refers to two or more elements that may be directly connected or connected via one or more intermediate elements. Similarly, the term “connected,” as used herein, refers to two or more elements that may be directly connected or connected via one or more intermediate elements. In addition, where used in this application, the terms “here,” “above,” “below,” and similar terms refer to the entire application and not to any particular part of it. Where contextually permissible, terms in the above detailed description that use singular or plural numbers may also include plural or singular numbers. The terms “or” and “or” referring to a list of two or more items cover all of the following interpretations of the term: any of the items in the list, all of the items in the list, and any combination of the items in the list.

[0075] Furthermore, unless specifically stated or understood otherwise in the context in which they are used, conditional language used herein, in particular, such as “can,” “may,” “may,” “for example,” and “like,” is generally intended to indicate that a given embodiment includes a given feature, element, and / or state, while other embodiments do not. That is, such conditional language is generally not intended to imply that the feature, element, and / or state exists in any manner necessary for one or more embodiments, or that one or more embodiments necessarily include logic to determine whether or not these features, elements, and / or states are included, or should be done, with or without the author’s input or prompt.

[0076] While certain embodiments have been described, these embodiments are presented only as examples and are not intended to limit the scope of this disclosure. In fact, the novel methods and systems described herein may be embodied in various other forms, and various omissions, substitutions, and modifications of the methods and systems described herein may be made without departing from the gist of this disclosure. For example, while blocks are presented in a given arrangement, alternative embodiments may perform similar functions with different components and / or circuit topologies, and some blocks may be deleted, moved, added, subdivided, combined, and / or modified. Each of these blocks may be implemented in various different manners. Any suitable combination of elements and operations of the various embodiments described above can be combined to give further embodiments. The appended claims and their equivalents are intended to cover forms or modifications that fall within the scope and gist of this disclosure.

Claims

1. 1. A bulk acoustic wave resonator device comprising: a layer of piezoelectric material having an upper surface and a lower surface; a first metal layer having a lower surface disposed on a top surface of the piezoelectric material layer and an upper surface; a second metal layer having an upper surface and a lower surface disposed on the lower surface of the piezoelectric material layer; a laterally dispersing raised frame including a first raised frame disposed on an upper surface of the first metal layer, the first raised frame having an inner raised frame section with a tapered portion and a non-tapered portion, and an outer raised frame section, and a second raised frame disposed below the first metal layer and the outer raised frame section but not below the inner raised frame section; Including, an inner raised frame section of the first raised frame disposed laterally a first distance from a central active area of ​​the bulk acoustic wave resonator device; an outer raised frame section of the first raised frame disposed laterally a second distance from a central active area of ​​the bulk acoustic wave resonator device; the second distance is greater than the first distance; A bulk acoustic wave resonator device, wherein the transversely dispersive raised frame is configured to improve reflection of transverse mode waves to reduce conversion of primary mode waves to transverse modes.

2. The bulk acoustic wave resonator device of claim 1 , wherein said first raised frame is formed from a metal.

3. The bulk acoustic wave resonator device of claim 2 , wherein said second raised frame is formed from an oxide.

4. The bulk acoustic wave resonator device of claim 1 , wherein the outer raised frame section of the first raised frame has a width and a substantially uniform thickness across the width.

5. The bulk acoustic wave resonator device of claim 1 , wherein the second raised frame includes an inner tapered portion and an outer non-tapered portion.

6. The bulk acoustic wave resonator device of claim 5 , wherein the inner tapered portion of the second raised frame has a taper angle of 10° to 60°.

7. The bulk acoustic wave resonator device of claim 5 , wherein the outer non-tapered portion of the second raised frame has a width and a substantially uniform thickness across the width.

8. 2. The bulk acoustic wave resonator device of claim 1, wherein the tapered portion of the inner raised frame section of the first raised frame has a taper angle of 5[deg.] to 45[deg.].

9. 2. The bulk acoustic wave resonator device of claim 1, further comprising a dielectric layer disposed on an upper surface of said first metal layer, said dielectric layer defining a recessed frame region surrounding said central active area.

10. The bulk acoustic wave resonator device of claim 1 , wherein the bulk acoustic wave resonator device does not include a recessed frame region.

11. 2. The bulk acoustic wave resonator device of claim 1, wherein the tapered portion of the inner raised frame section of the first raised frame has a width that is narrower than a width of the non-tapered portion of the inner raised frame section of the first raised frame.

12. 2. The bulk acoustic wave resonator device of claim 1, wherein the tapered portion of the inner raised frame section of the first raised frame has a width greater than a width of the non-tapered portion of the inner raised frame section of the first raised frame.

13. 2. The bulk acoustic wave resonator device of claim 1, wherein said second raised frame has an upper surface in contact with a lower surface of said first metal layer.

14. 2. The bulk acoustic wave resonator device of claim 1, wherein said second raised frame has a lower surface in contact with a top surface of said second metal layer.

15. The bulk acoustic wave resonator device of claim 14 , wherein the second raised frame has a top surface in contact with the layer of piezoelectric material.

16. The bulk acoustic wave resonator device of claim 1 , wherein the second raised frame has a top surface in contact with the layer of piezoelectric material.

17. the second raised frame has a lower surface in contact with the piezoelectric material layer; 17. The bulk acoustic wave resonator device of claim 16, wherein the second raised frame divides the piezoelectric material layer into an upper piezoelectric material layer and a lower piezoelectric material layer.

18. 2. The bulk acoustic wave resonator device of claim 1 , wherein the first raised frame is formed from a material having a higher acoustic impedance than a material from which the second raised frame is formed and a higher acoustic impedance than a material from which the piezoelectric material layer is formed.

19. 2. The bulk acoustic wave resonator device of claim 1 , wherein the second raised frame is formed from a material having a lower acoustic impedance than the material from which the first raised frame is formed and a lower acoustic impedance than the material from which the piezoelectric material layer is formed.

20. 2. The bulk acoustic wave resonator device of claim 1, wherein the bulk acoustic wave resonator device is a thin film bulk acoustic wave resonator device including a cavity defined below the second metal layer.

21. 2. The bulk acoustic wave resonator device of claim 1, wherein the bulk acoustic wave resonator device is a solid-mounted resonator including a Bragg reflector disposed below the second metal layer.

22. The bulk acoustic wave resonator device of claim 1 , wherein the tapered portion of the inner raised frame section of the first raised frame has a linear taper.

23. The bulk acoustic wave resonator device of claim 1 , wherein the tapered portion of the inner raised frame section of the first raised frame has a concave taper.

24. The bulk acoustic wave resonator device of claim 1 , wherein the tapered portion of the inner raised frame section of the first raised frame has a convex taper.

25. The bulk acoustic wave resonator device of claim 1 , wherein the second raised frame includes an inner tapered portion having a linear taper.

26. The bulk acoustic wave resonator device of claim 1 , wherein the second raised frame includes an inner tapered portion having a concave taper.

27. The bulk acoustic wave resonator device of claim 1 , wherein the second raised frame includes an inner tapered portion having a convex taper.

28. 28. A radio frequency filter comprising a bulk acoustic wave resonator device according to any one of claims 1 to 27.

29. 30. A radio frequency module comprising the radio frequency filter of claim 28.

30. 30. A radio frequency device comprising the radio frequency module of claim 29.

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