ACOUSTIC WAVE FILTERS WITH IMPROVED SECOND HARMONIC RESPONSE

A first acoustic wave device can have a piezoelectric layer between a first electrode and a second electrode. The first acoustic wave device can have a first shape and a first area. A second acoustic wave device can be coupled to the first acoustic wave device to at least partially cancel a second harmonic response of the first acoustic wave device. The second acoustic wave device can have a piezoelectric layer between a first electrode and a second electrode. The second acoustic wave device can have a second shape that is different from the first shape and a second area that is within a threshold amount of the first area.

BACKGROUND

Technical Field

Embodiments of this disclosure relate to filters having acoustic wave devices, such as bulk acoustic wave devices, and more particularly to suppressing nonlinear responses such as second harmonic responses in the acoustic wave devices.

Description of Related Technology

Acoustic wave filters can be implemented in radio frequency electronic systems. For instance, filters in a radio frequency front end of a mobile phone can include acoustic wave filters. An acoustic wave filter can include a plurality of acoustic resonators arranged to filter a radio frequency signal. Example acoustic wave filters include surface acoustic wave (SAW) filters and bulk acoustic wave (BAW) filters.

Although various filters with BAW devices exist, there remains a need for improved filters with BAW devices, such as with improved suppression of nonlinear response.

SUMMARY OF CERTAIN INVENTIVE ASPECTS

Various embodiments disclosed herein can relate to a filter, which can include a first acoustic wave device having a piezoelectric layer between a first electrode and a second electrode. The first acoustic wave device can have a first shape and a first area. A second acoustic wave device can be coupled to the first acoustic wave device to at least partially cancel a second harmonic response of the first acoustic wave device. The second acoustic wave device can have a piezoelectric layer between a first electrode and a second electrode. The second acoustic wave device can have a second shape that is different from the first shape and a second area that can be within about 10% of the first area.

The first acoustic wave device can have a first perimeter length, and the second acoustic wave device can have a second perimeter length that is within about 10% of the first perimeter length. The first acoustic wave device can include a first raised frame on a first side of the first acoustic wave device and a second raised frame on a second side of the first acoustic wave device. The second acoustic wave device can include a first raised frame on a first side of the second acoustic wave device and a second raised frame on a second side of the second acoustic wave device. A perimeter portion length of the first raised frame on the first acoustic wave device can be within about 10% of a perimeter portion length of the first raised frame on the second acoustic wave device, and/or a perimeter portion length of the second raised frame on the first acoustic wave device can be within about 10% of a perimeter portion length of the second raised frame on the second acoustic wave device. The first raised frame of the first acoustic wave device can have a first raised frame area, the second raised frame of the first acoustic wave device can have a second raised frame area, the first raised frame of the second acoustic wave device can have a first raised frame area, the second raised frame of the second acoustic wave device can have a second raised frame area, the first raised frame area of the first acoustic wave device can be within about 10% of the first raised frame area of the second acoustic wave device, and/or the second raised frame area of the first acoustic wave device can be within about 10% of the second raised frame area of the second acoustic wave device. The first acoustic wave device can have an inner active area between the first raised frame and the second raised frame, the second acoustic wave device can have an inner active area between the first raised frame and the second raised frame, and the size of the inner active area of the first acoustic wave device can be within about 10% of the size of the inner active area of the second acoustic wave device.

The first acoustic wave device can have a first electrically conductive layer that is electrically coupled to the first electrode along a first electrical connection having a first electrode connection length, the first acoustic wave device has a second electrically conductive layer that is electrically coupled to the second electrode along a second electrical connection having a second electrode connection length, the second acoustic wave device has a first electrically conductive layer that is electrically coupled to the first electrode along a first electrical connection having a first electrode connection length, the second acoustic wave device has a second electrically conductive layer that is electrically coupled to the second electrode along a second electrical connection having a second electrode connection length, the first electrode connection length of the first acoustic wave device is within about 10% of the first electrode connection length of the second acoustic wave device, and the second electrode connection length of the first acoustic wave device is within about 10% of the second electrode connection length of the second acoustic wave device.

The first acoustic wave device can be electrically coupled to the second acoustic wave device so that electrical current flows through the first acoustic wave device and the second acoustic wave device in opposite directions. The first acoustic wave device and the second acoustic wave device can have opposite voltage polarities across the piezoelectric layer. The first acoustic wave device can be coupled in series with the second acoustic wave device with either i) the first electrode of the first acoustic wave device electrically coupled to the first electrode of the second acoustic wave device, or ii) the second electrode of the first acoustic wave device electrically coupled to the second electrode of the second acoustic wave device. The filter can include a third acoustic wave device that can have a piezoelectric layer between a first electrode and a second electrode. The third acoustic wave device can have a third shape and a third area. The filter can include a fourth acoustic wave device which can have a piezoelectric layer between a first electrode and a second electrode. The fourth acoustic wave device can have a fourth shape that is different from the third shape and a fourth area that can be within about 10% of the third area. The fourth acoustic wave device can be coupled in series with the third acoustic wave device. The pair of the first and second acoustic wave devices can be coupled in parallel with the pair of the third and fourth acoustic wave devices. The first acoustic wave device can be coupled in parallel with the second acoustic wave device, and/or the first electrode of the first acoustic wave device electrically can be coupled to the second electrode of the second acoustic wave device. The filter can include a third acoustic wave device that can have a piezoelectric layer between a first electrode and a second electrode. The third acoustic wave device can have a third shape and a third area. The filter can include a fourth acoustic wave device that can have a piezoelectric layer between a first electrode and a second electrode. The fourth acoustic wave device can have a fourth shape that is different from the third shape and a fourth area that can be within about 10% of the third area. The fourth acoustic wave device can be coupled in parallel with the third acoustic wave device. The pair of the first and second acoustic wave devices can be coupled in series with the pair of the third and fourth acoustic wave devices. The first area, the second area, the third area, and the fourth area can vary by not more than about 10%. The first acoustic wave device can have a first perimeter length, the second acoustic wave device can have a second perimeter length, the third acoustic wave device can have a third perimeter length, and the fourth acoustic wave device can have a fourth perimeter length. The first perimeter length, the second perimeter length, the third perimeter length, and the fourth perimeter length can vary by not more than about 10%.

The first acoustic wave device can include a substrate, and the first electrode can be between the piezoelectric layer and the substrate. The second acoustic wave device can include a substrate, and the first electrode can be between the piezoelectric layer and the substrate. The first acoustic wave device can be a bulk acoustic wave device, and the second acoustic wave device can be a bulk acoustic wave device.

Various embodiments disclosed herein can relate to a system, which can include a first bulk acoustic wave resonator that can include a substrate, a first electrode, a piezoelectric layer, and a second electrode. The piezoelectric layer can be between the first electrode and the second electrode. The first electrode can be between the piezoelectric layer and the substrate. The first bulk acoustic wave resonator can have a first shape, a first area, and a first perimeter length. The system can include a second bulk acoustic wave resonator that can include a substrate, a first electrode; a piezoelectric layer, and a second electrode. The piezoelectric layer can be between the first electrode and the second electrode. The first electrode can be between the piezoelectric layer and the substrate. The second bulk acoustic wave resonator can have a second shape that is different from the first shape, a second area that can vary by not more than about 10% from the first area, and a second perimeter length that can vary by not more than about 10% from the first perimeter length.

The first bulk acoustic wave device can include a first raised frame on a first side of the first bulk acoustic wave device with a first length and a second raised frame on a second side of the first bulk acoustic wave device with a second length. The second bulk acoustic wave device can include a first raised frame on a first side of the second bulk acoustic wave device and a second raised frame on a second side of the second bulk acoustic wave device. The first length of the first raised frame on the first bulk acoustic wave device can be within about 10% of the first length of the first raised frame on second bulk acoustic wave device. The second length of the second raised frame on the first bulk acoustic wave device can be within about 10% of second length of the second raised frame on the second acoustic wave device. The first bulk acoustic wave device can have an inner active area disposed inward of the first raised frame and the second raised frame. The second acoustic wave device can have an inner active area disposed inward of the first raised frame and the second raised frame. The size of the inner active area of the first acoustic wave device can be within about 10% of the size of the inner active area of the second acoustic wave device.

The first bulk acoustic wave device can have a first nonlinear response. The second bulk acoustic wave device can have a second nonlinear response. The first and second bulk acoustic wave devices can be coupled to at least partially cancel a first and second nonlinear responses. The first electrode of the first bulk acoustic wave device can be electrically coupled to the first electrode of the second bulk acoustic wave device, or the second electrode of the first bulk acoustic wave device can be electrically coupled to the second electrode of the second bulk acoustic wave device, such as to electrically couple the first and second bulk acoustic wave devices in series. The first electrode of the first bulk acoustic wave device can be coupled to the second electrode of the second bulk acoustic wave device, and the second electrode of the first bulk acoustic wave device can be coupled to the first electrode of the second bulk acoustic wave device, such as to electrically couple the first and second bulk acoustic wave devices in parallel.

Various embodiments disclosed herein can relate to an acoustic wave filter that can include a first bulk acoustic wave resonator that can include a piezoelectric layer between a lower electrode and an upper electrode. The first bulk acoustic wave resonator can have a first shape and a first perimeter length. A second bulk acoustic wave resonator can have a piezoelectric layer between a lower electrode and an upper electrode. The second bulk acoustic wave resonator can have a second shape that can be different from the first shape and a second perimeter length that can vary by not more than about 10% from the first perimeter length.

The second bulk acoustic wave resonator can be configured to at least partially cancel a second harmonic response of the first bulk acoustic wave resonator. The first bulk acoustic wave resonator can be electrically coupled to the second bulk acoustic wave resonator so that electrical current flows through the first bulk acoustic wave resonator from the upper electrode to the lower electrode, and so that electrical current flows through the second bulk acoustic wave resonator from the lower electrode to the upper electrode. The first bulk acoustic wave resonator can be electrically coupled to the second bulk acoustic wave resonator to provide a voltage drop from the upper electrode to the lower electrode in the first bulk acoustic wave resonator and to provide a voltage drop from the lower electrode to the upper electrode in the second bulk acoustic wave resonator. An active region of the first bulk acoustic wave resonator where the lower electrode, the piezoelectric layer, and the upper electrode overlap can have a first area. An active region of the second bulk acoustic wave resonator where the lower electrode, the piezoelectric layer, and the upper electrode overlap can have a second area that can vary by not more than about 10% from the first area.

The first bulk acoustic wave resonator can include a first raised frame on a first side of the first bulk acoustic wave resonator and the lower electrode can extend outward past the piezoelectric layer. The first raised frame of the first bulk acoustic wave resonator can have a first length and a first area. The first bulk acoustic wave resonator can include a second raised frame on a second side of the first bulk acoustic wave resonator and the upper electrode can extend outward past the piezoelectric layer. The second raised frame of the first bulk acoustic wave resonator can have a second length and a second area. The second bulk acoustic wave resonator can include a first raised frame on a first side of the second bulk acoustic wave resonator and the lower electrode can extend outward past the piezoelectric layer. The first raised frame of the second bulk acoustic wave device can have a third length and a third area. The second bulk acoustic wave resonator can include a second raised frame on a second side of the second bulk acoustic wave resonator and the upper electrode can extend outward past the piezoelectric layer. The second raised frame of the second bulk acoustic wave device can have a fourth length and a fourth area. In some embodiments, either i) the upper electrode of the first bulk acoustic wave resonator can be electrically coupled to the upper electrode of the second bulk acoustic wave resonator, or ii) the lower electrode of the first bulk acoustic wave resonator can be electrically coupled to the lower electrode of the second bulk acoustic wave resonator, such as to electrically couple the first and second bulk acoustic wave resonator in series. The first length and/or the first area of the first raised frame on the first bulk acoustic wave resonator can be within about 10% of the third length and/or third area of the first raised frame on the second bulk acoustic wave resonator. The second length and/or second area of the second raised frame on the first bulk acoustic wave resonator can be within about 10% of the fourth length and/or fourth area of the second raised frame on the second acoustic wave resonator. In some embodiments, either i) the lower electrode of the first bulk acoustic wave resonator can be coupled to the upper electrode of the second bulk acoustic wave resonator, or ii) the upper electrode of the first bulk acoustic wave resonator can be coupled to the lower electrode of the second bulk acoustic wave device, such as to electrically couple the first and second bulk acoustic wave resonators in parallel. The first length and/or the first area of the first raised frame on the first bulk acoustic wave resonator can be within about 10% of the fourth length and/or fourth area of the second raised frame on the second bulk acoustic wave resonator. The second length and/or second area of the second raised frame on the first bulk acoustic wave resonator can be within about 10% of the third length and/or third area of the first raised frame on the second acoustic wave resonator. The first bulk acoustic wave resonator can have a main acoustically active area disposed inward of the first raised frame and the second raised frame. The second acoustic wave resonator can have a main acoustically active area inward of the first raised frame and the second raised frame. An area of the main acoustically active area of the first acoustic wave device can be within about 10% of an area of the main acoustically active area of the second acoustic wave device.

Various embodiments disclosed herein can relate to a filter that can include first and second bulk acoustic wave devices that each can include a piezoelectric layer between a lower electrode and an upper electrode, an active region with an overlap shape where the lower electrode, piezoelectric layer, and upper electrode overlap, a first conductive layer that is electrically coupled to a portion of the lower electrode and that extends laterally past the active region on a first side of the bulk acoustic wave device, a second conductive layer that is electrically coupled to a portion of the upper electrode that extends laterally past the active region on a second side of the bulk acoustic wave device, a first raised frame structure on the first side of the bulk acoustic wave device, and a second raised frame structure on the second side of the bulk acoustic wave device. The second bulk acoustic wave device can be coupled to the first bulk acoustic wave device to at least partially cancel a second harmonic response of the first bulk acoustic wave device. The overlap shape of the second bulk acoustic wave device can have a second shape different from a first shape of the overlap shape of the first bulk acoustic wave device.

The first raised frame structure of the first bulk acoustic wave device can have a first length extending from a first end to a second end of the first raised frame structure. The second raised frame structure of the first bulk acoustic wave device can have a second length extending from a first end to a second end of the second raised frame structure. The first raised frame structure of the second bulk acoustic wave device can have a third length extending from a first end to a second end of the first raised frame structure. The second raised frame structure of the second bulk acoustic wave device can have a fourth length extending from a first end to a second end of the second raised frame structure. The third length can be is within about 10% of the first length. The fourth length can be within about 10% of the second length. In some embodiments, either i) the first conductive layer of the first bulk acoustic wave device can be electrically coupled to the first conductive layer of the second bulk acoustic wave device, or ii) the second conductive layer of the first bulk acoustic wave device can be electrically coupled to the second conductive layer of the second bulk acoustic wave device, such as so that the first and second bulk acoustic wave devices are coupled in series. The third length can be within about 10% of the second length. The fourth length can be within about 10% of the first length. In some embodiments, either i) the first conductive layer of the first bulk acoustic wave device can be electrically coupled to the second conductive layer of the second bulk acoustic wave device, or ii) the second conductive layer of the first bulk acoustic wave device can be electrically coupled to the first conductive layer of the second bulk acoustic wave device, so that the first and second bulk acoustic wave devices are coupled in parallel. The first bulk acoustic wave device can have a first gap between the first ends of the first and second raised frame structures and a second gap between the second ends of the first and second raised frame structures. The second bulk acoustic wave device can have a first gap between the first ends of the first and second raised frame structures and a second gap between the second ends of the first and second raised frame structures.

An area of the first raised frame structure of the first bulk acoustic wave device can be within about 10% of an area of the first raised frame structure of the second bulk acoustic wave device. An area of the second raised frame structure of the first bulk acoustic wave device can be within about 10% of an area of the second raised frame structure of the second bulk acoustic wave device. In some embodiments, either i) the first conductive layer of the first bulk acoustic wave device can be electrically coupled to the first conductive layer of the second bulk acoustic wave device, or ii) the second conductive layer of the first bulk acoustic wave device can be electrically coupled to the second conductive layer of the second bulk acoustic wave device, so that the first and second bulk acoustic wave devices are coupled in series. An area of the first raised frame structure of the first bulk acoustic wave device can be within about 10% of an area of the second raised frame structure of the second bulk acoustic wave device. An area of the second raised frame structure of the first bulk acoustic wave device can be within about 10% of an area of the first raised frame structure of the second bulk acoustic wave device. In some embodiments, either i) the first conductive layer of the first bulk acoustic wave device is electrically coupled to the second conductive layer of the second bulk acoustic wave device, or ii) the second conductive layer of the first bulk acoustic wave device is electrically coupled to the first conductive layer of the second bulk acoustic wave device, so that the first and second bulk acoustic wave devices are coupled in parallel.

The active region of the first bulk acoustic wave device can have a first area, and the active region of the second bulk acoustic wave device can have a second area that can be within about 10% of the first area. The active region of the first bulk acoustic wave device can have a first perimeter, and the active region of the second bulk acoustic wave device can have a second perimeter that can be within about 10% of the first perimeter. The first bulk acoustic wave device can have a center portion of the active area that is inward of the first raised frame structure and the second raised frame structure, and the center portion can have an area. The second bulk acoustic wave device can have a center portion of the active area that is inward of the first raised frame structure and the second raised frame structure, and the center portion can have an area that can be within about 10% of the area of the center portion of the first bulk acoustic wave device.

The first conductive layer of the first bulk acoustic wave device can be electrically coupled to a portion of the lower electrode along a first electrical connection having a first electrode connection length. The second conductive layer of the first bulk acoustic wave device can be electrically coupled to a portion of the upper electrode along a second electrical connection having a second electrode connection length. A first conductive layer of the second bulk acoustic wave device can be electrically coupled to a portion of the lower electrode along a first electrical connection having a first electrode connection length that can be within about 10% of the first electrical connection length of the first bulk acoustic wave device. The second conductive layer of the second bulk acoustic wave device can be electrically coupled to a portion of the upper electrode along a second electrical connection having a second electrode connection length that can be within about 10% of the second electrical connection length of the first bulk acoustic wave device. In some embodiments, either i) the first conductive layer of the first bulk acoustic wave device can be electrically coupled to the first conductive layer of the second bulk acoustic wave device, or ii) the second conductive layer of the first bulk acoustic wave device can be electrically coupled to the second conductive layer of the second bulk acoustic wave device, so that the first and second bulk acoustic wave devices are coupled in series. The first conductive layer of the first bulk acoustic wave device can be electrically coupled to a portion of the lower electrode along a first electrical connection having a first electrode connection length. The second conductive layer of the first bulk acoustic wave device can be electrically coupled to a portion of the upper electrode along a second electrical connection having a second electrode connection length. A first conductive layer of the second bulk acoustic wave device can be electrically coupled to a portion of the lower electrode along a first electrical connection having a first electrode connection length that can be within about 10% of the second electrical connection length of the first bulk acoustic wave device. The second conductive layer of the second bulk acoustic wave device can be electrically coupled to a portion of the upper electrode along a second electrical connection having a second electrode connection length that can be within about 10% of the first electrical connection length of the first bulk acoustic wave device. In some embodiments, either i) the first conductive layer of the first bulk acoustic wave device can be electrically coupled to the second conductive layer of the second bulk acoustic wave device, or ii) the second conductive layer of the first bulk acoustic wave device can be electrically coupled to the first conductive layer of the second bulk acoustic wave device, so that the first and second bulk acoustic wave devices are coupled in parallel.

The filter can include a third bulk acoustic wave device and a fourth bulk acoustic wave device. The combined first bulk acoustic wave device, second bulk acoustic wave device, third bulk acoustic wave device, and fourth bulk acoustic wave device can have a combined second harmonic response that is smaller than a second harmonic response of any individual one of the first bulk acoustic wave device, the second bulk acoustic wave device, the third bulk acoustic wave device, and the fourth bulk acoustic wave device.

Various embodiments disclosed herein can relate to a filter, which can include first and second bulk acoustic wave devices, which each can include a piezoelectric layer between a lower electrode and an upper electrode, a first conductive layer electrically coupled to a portion of the lower electrode along a first electrical connection having a first electrode connection length, and a second conductive layer electrically coupled to a portion of the upper electrode along a second electrical connection having a second electrode connection length. The second bulk acoustic wave device can have a second shape different from a first shape of the first bulk acoustic wave device. The second bulk acoustic wave device can be coupled to the first bulk acoustic wave device to at least partially cancel a second harmonic response of the first bulk acoustic wave device. The first electrode connection length of the second bulk acoustic wave device can be within about 10% of the first electrical connection length of the first bulk acoustic wave device. The second electrode connection length of the second bulk acoustic wave device can be within about 10% of the second electrical connection length of the first bulk acoustic wave device.

The first bulk acoustic wave device can have an active region where the lower electrode, piezoelectric layer, and upper electrode overlap, and the active region of the first bulk acoustic wave device can have a first area. The second bulk acoustic wave device can have an active areas where the lower electrode, piezoelectric layer, and upper electrode overlap, and the active region of the first bulk acoustic wave device can have a second area that can be within about 10% of the first area. The first bulk acoustic wave device can have an active region where the lower electrode, piezoelectric layer, and upper electrode overlap, and the active region of the first bulk acoustic wave device can have a first perimeter length. The second bulk acoustic wave device can have an active area where the lower electrode, piezoelectric layer, and upper electrode overlap, and the active region of the second bulk acoustic wave device having a second perimeter length that is within about 10% of the first perimeter length. In some embodiments, either i) the first conductive layer of the first bulk acoustic wave device can be electrically coupled to the first conductive layer of the second bulk acoustic wave device, or ii) the second conductive layer of the first bulk acoustic wave device can be electrically coupled to the second conductive layer of the second bulk acoustic wave device, so that the first and second bulk acoustic wave devices can be coupled in series. In some embodiments, the first conductive layer of the first bulk acoustic wave device can be electrically coupled to the second conductive layer of the second bulk acoustic wave device, and the second conductive layer of the first bulk acoustic wave device can be electrically coupled to the first conductive layer of the second bulk acoustic wave device, so that the first and second bulk acoustic wave devices can be coupled in parallel.

Various embodiments disclosed herein can relate to a radio frequency filter, which can include a plurality of bulk acoustic wave devices. Each of the plurality of bulk acoustic wave devices can be coupled to at least one other of the plurality of bulk acoustic wave devices to at least partially cancel a second harmonic response of the at least one other of the plurality of bulk acoustic wave devices. Each of the plurality of bulk acoustic wave devices can have a piezoelectric layer between a first electrode and a second electrode. Each of the plurality of bulk acoustic wave devices can have a unique shape that is different from all the other bulk acoustic wave devices of the filter.

The plurality of bulk acoustic wave devices can include at least 2, at least 3, at least 4, at least 6, at least 8, at least 10, at least 12, or more bulk acoustic wave devices with unique shapes. The plurality of bulk acoustic wave devices can includes at least two bulk acoustic wave devices that are coupled to at least partially cancel each other's second harmonic responses. The at least two bulk acoustic wave devices can have different shapes and can have sizes that differ by not more than about 10%. The at least two bulk acoustic wave devices can have perimeters that differ by not more than about 10%. The at least two bulk acoustic wave devices can each have two raised frame structures with areas that can differ from corresponding areas of two raised frame structures on the others of the at least two bulk acoustic wave devices by not more than about 10%. The at least two bulk acoustic wave devices can each have two raised frame structures with lengths that differ from corresponding lengths of two raised frame structures on the others of the at least two bulk acoustic wave devices by not more than about 10%. The at least two of the plurality of bulk acoustic wave devices can be coupled in series as resonator sub-elements of a resonator of the filter. At least two of the plurality of bulk acoustic wave devices can be coupled in parallel as resonator sub-elements of a resonator.

The various different parameters that are identified as being within about 10% or as varying by not more than 10%, or the like, can be within or can vary by not more than about 10%, about 8%, about 6%, about 5%, about 4%, about 3%, about 2%, about 1%, about 0.75%, about 0.5%, about 0.25%, about 0.2%, about 0.15%, about 0.1%, or less, or any values or ranges between any of these values.

DETAILED DESCRIPTION

Acoustic resonators, including bulk acoustic wave (BAW) resonators, can be used in radio frequency (RF) filters and communications systems. In some filter configurations, one or more BAW resonators can have non-linear behavior, such as a second harmonic response (H2). In general it can be advantageous for the second harmonic response, and/or other nonlinear responses, to be as low as possible. In some embodiments, BAW resonators can be cascaded in a manner than removes or reduces the H2 response. For example, a resonator of the filter can include two resonator sub-elements. A first of the two resonator sub-elements can produce a first H2 response, and the second of the two resonator sub-elements can produce a second H2 response that at least partially cancels the first H2 response. Accordingly, the total H2 response of the resonator can be reduced or removed.

FIG.1is a plan view of an example of a layout for an acoustic wave filter100.FIG.2is a plan view of another example implementation of an acoustic wave filter100. The filter100can include a plurality of acoustic wave devices102, such as BAW resonators or devices102a-m, which can be coupled to a die104, substrate, or base material. The example ofFIG.1has 13 BAW resonators102a-m, but any suitable number of BAW resonators can be used. Some layers and components of the filter100are omitted from view inFIG.1for ease of illustration. The filter100can have one or more connection points106a-f, such as contact pads, which can be used, for example, to deliver input signals to, or to receive output signals from, the filter100. The filter100can include electrical connections108,110between the BAW devices102a-m. The filter100can include lower electrical connections108to the lower electrodes of the BAW devices102a-m, which is shown inFIG.1with a first pattern (e.g., in the periodic speckle pattern), and upper electrical connections110to the upper electrodes of the BAW devices102a-m, which is shown inFIG.1with a second pattern (e.g., in the irregular speckle pattern). InFIGS.1,2,4,7,9, and11, the periodic speckle pattern is used to indicate the lower electrical connections108to the lower electrodes, and the irregular speckle pattern is used to indicate the upper electrical connections110to the upper electrodes. In some cases, the filter100can include one or more electrical couplings112between the lower electrical connection108and the upper electric connection110. The electrical coupling112can be accomplished using one or more vias, other vertical electrical couplings, or any other suitable electrical coupling mechanism or manner. The electrical couplings112can be used to couple a lower electrode126of one BAW device (e.g., BAW device HA102a) to an upper electrode130of a second BAW device (e.g., BAW device P1B102b).

FIG.3is a cross-sectional view of an example of a bulk acoustic wave (BAW) device102, which can be used by the filter100. The BAW device102can includes a support substrate120, a cavity122, a first or lower electrode126positioned over the support substrate120, a piezoelectric layer128positioned over the lower electrode126, and a second or upper electrode130positioned over the piezoelectric layer128. The support substrate120can be a silicon substrate, and other suitable substrates can alternatively be implemented in place of the silicon substrate. One or more layers, such as a passivation layer, can be positioned between the lower electrode126and the support substrate120. InFIG.3, a passivation layer124can be disposed between the substrate120and the lower electrode126. The layer124can be an insulating or dielectric material. The layer124can be an oxide layer, and can include silicon dioxide, although any suitable material could be used. The layer124can be disposed between the substrate120and the cavity122. In some embodiments, a portion of the material of layer124can be disposed between the cavity and the first electrode126and/or piezoelectric layer128. The cavity122can be a recess formed in the substrate120material, or the first electrode126, piezoelectric layer128, and/or second electrode130can be elevated to provide the cavity122(as shown inFIG.3). In some embodiments, the cavity122can be an air cavity.

The piezoelectric layer128can be disposed between the first electrode126and the second electrode130. The piezoelectric layer128can be an aluminum nitride (AlN) layer or any other suitable piezoelectric layer. The lower electrode126and/or the upper electrode130can have a relatively high acoustic impedance. For example, the lower electrode126and/or the upper electrode130can include molybdenum (Mo), tungsten (W), ruthenium (Ru), iridium (Jr), platinum (Pt), Ir/Pt, or any suitable alloy and/or combination thereof, although other suitable conductive materials could be used. The upper electrode130can be formed of the same material as the lower electrode126in certain instances, although different materials can be used for the lower electrode126and the upper electrode130, in some cases. In some embodiments, a passivation layer132can be disposed over the upper electrode130. The passivation layer132can be made of silicon dioxide, although various other insulating or dielectric materials could be used. The passivation layer132can be an oxide layer. In some cases, the passivation layer132can be omitted.

An active region134or active domain of the BAW device102can be defined by the portion of the piezoelectric layer128that overlaps with both the lower electrode126and the upper electrode130, for example over an acoustic reflector, such as the cavity122. The BAW device102can include a raised frame structure, in some embodiments. The BAW device102can have a first raised frame structure136, which can be on a first side of the BAW device102that is electrically coupled to the lower electrode126. The lower electrode126can extend laterally past the active region134and/or laterally past the upper electrode130on the first side of the BAW device102. The lower electrode126can be in contact with a first conductive layer140at a lower electrode connection160, for example, outside the active region134. The first conductive layer140can be used to transfer electricity to or from the first or lower electrode126. Electricity can be transferred to or from the first or lower electrode126(e.g., via the first conductive layer140) on the first side of the BAW device102that has the first raised frame structure136. The first raised frame structure136can be a lower electrode connected raised frame, for example because the first raised frame structure136can be positioned on the side of the BAW device102with the electrical connection to the lower electrode126. The BAW device102can have a second raised frame structure138, which can be on a second side of the BAW device102(e.g., in some cases opposite the first side). The second side of the BAW device102can be electrically coupled to the upper electrode130. The upper electrode130can extend laterally past the active region134and/or laterally past the lower electrode126on the second side of the BAW device102. The upper electrode130can be in contact with a second conductive layer142at an upper electrode connection162, for example, outside the active region134. The second conductive layer142can be used to transfer electricity to or from the second or upper electrode130. A third conductive layer144can be formed (e.g., deposited) over the first conductive layer140and/or the second conductive layer142. The additional conductive layer144can be beneficial for selecting specific chemical, mechanical, and/or electrical characteristics. In some embodiments, the conductive layers140and142can be a first conductive material (e.g., gold (Au)), and the additional conductive layer144can be a second conductive material (e.g., copper (Cu)). In some embodiments, the additional conductive layer144can be omitted. Electricity can be transferred to or from the second or upper electrode130(e.g., via the second conductive layer142) on the second side of the BAW device102, which has the second raised frame structure138. The second raised frame structure138can be an upper electrode connected raised frame, for example because the second raised frame structure138can be positioned on the side of the BAW device102with the electrical connection to the upper electrode130. The electrical connection160from the conductive layer140to the lower electrode126can be the lower electrode perimeter or edge. The electrical connection162from the conductive layer140to the upper electrode130can be the upper electrode perimeter or edge. In some embodiments, the first conductive layer140and/or the second conductive layer142can be omitted, and the material of the lower electrode126and/or the upper electrode130can extend beyond the BAW device102can deliver signals to and/or the BAW device102.

FIG.4shows a plan view of an example BAW device, which can be the BAW device102jofFIG.2, for example. The cross-sectional view of a BAW device102can be taken along the line from A to A′ inFIG.4. Gaps146can separate the first raised frame structure136from the second raised frame structure138. The raised frame structures136,138can extend along less than the full perimeter of the BAW device102or active region134, such as about 75%, about 80%, about 85%, about 90%, about 93%, about 95%, about 97%, about 98%, about 99% or the full perimeter, or any values or ranges between any of these values. At the gaps146, the top of the active region134can be flat (e.g., flush with a center portion148of the active region134), without the raised portions that provide the raised frame structures136,138. The center portion148can be a main acoustically active region of the BAW device102. In some embodiments, the main acoustically active region148can set the main resonant frequency of the BAW device102, and there can be a significant (e.g., exponential) fall off of acoustic energy in the piezoelectric layer128for a main mode in the regions of the raised frame structures136and138relative to the main acoustically active region148. The first raised frame portion136can have a first width150, which can be substantially the same as a second width152of the second raised frame structure138. The first raised frame structure136can have a first height, which can be substantially the same as a second height of the second raised frame structure138. Other configurations are possible, such as having different heights and/or widths for the raised frame structures136,138.

The raised frame structures136and/or138can be formed by regions of the upper electrode130with increased thickness. In some cases, additional conductive material (e.g., the same material as the electrode130) can be formed over the upper electrode130to form the thicker regions to provide the raised frame structures136,138. In some embodiments, the upper electrode130can have a first thickness at the central portion or main acoustically active region148, and a second thickness at one or both of the raised frame structures136,138, and the second thickness can be greater than the first thickness.

Various other BAW devices could be used.FIG.5shows a cross-sectional view of another example embodiment of a BAW device102. The BAW device102can have a raised frame layer154positioned at least partially between the piezoelectric layer128and the upper electrode130. A first portion of the raised frame layer154can form the first raised frame structure136. A first raised frame region150of the BAW device102can be defined by the portion of the first raised frame structure in the active region134of the BAW102. A second portion of the raised frame layer154can form the second raised frame structure138. A second raised frame region152of the BAW device102can be defined by the portion of the second raised frame structure in the active region134of the BAW102. The raised frame layer154can be positioned between the first or lower electrode126and the second or upper electrode130. The raised frame layer154can have gaps, which can provide the two separate raised frame structures136and138. The raised frame layer154can be positioned over the upper or second electrode130, in some embodiments. In some embodiments, the raised frame structures136and138can be formed by a thicken regions of the piezoelectric layer124, or by thickened regions of the lower electrode126, or by thickened regions of the upper electrode130, or by a raised frame layer154positioned between the piezoelectric layer128and the lower electrode126, or between the piezoelectric layer128and the upper electrode130, or at any other suitable location to produce the raised frame structures136,138with elevated heights.

In some embodiments, the raised frame layer154can be a low acoustic impedance material. The low acoustic impedance material can have a lower acoustic impedance than the material of the first electrode126. The low acoustic impedance material has a lower acoustic impedance than the material of the second electrode130. The low acoustic impedance material can have a lower acoustic impedance than the material of the piezoelectric layer124. As an example, the raised frame layer154can be a silicon dioxide (SiO2) layer, although other oxides and other suitable materials can be used. Since silicon dioxide is already used in a variety of bulk acoustic wave devices, a silicon dioxide first raised frame layer120can be relatively easy to manufacture. The first raised frame layer120can have a relatively low density. The density and/or acoustic impedance of the first raised frame layer120can be lower than the density and/or acoustic impedance of the lower electrode114, of the upper electrode118, of the piezoelectric layer116.

In some embodiments, the raised frame layer154can be a relatively high acoustic impedance material. The raised frame layer154can include a relatively high density material. For instance, the raised frame layer154can include molybdenum (Mo), tungsten (W), ruthenium (Ru), platinum (Pt), iridium (Ir), the like, or any suitable alloy thereof. The raised frame layer154can be a metal layer. Alternatively, the raised frame layer154can be a suitable non-metal material with a relatively high density. The density and/or acoustic impedance of the raised frame layer154can be similar to or greater than the density and/or acoustic impedance of the lower electrode114, of the upper electrode118, and/or of the piezoelectric layer116of the BAW device102. In some instances, the raised frame layer154can be of the same material as the lower electrode114and/or the upper electrode118of the BAW device102. In some implementations, the raised frame layer154can be a thickened region of the same material that makes up the upper electrode130. The upper electrode130and the raised frame layer154can be formed by different processing steps, and in some cases there can be a resulting identifiable transition between the upper electrode130and the raised frame layer154of the same material, although some implementations may not have an identifiable transition between the upper electrode130and the raised frame layer154. In some embodiments, the raised frame structure can include a layer of a relatively low acoustic impedance material, and a layer of relatively high acoustic impedance. Any suitable raised frame structures136,138can be used.

The BAW devices102disclosed herein can be film bulk acoustic wave resonators (FBARs), as illustrated inFIG.3, for example. A cavity122can be included, such as below the first or lower electrode126. The cavity122can be filled with air, in some implementations. The cavity122can be defined by the geometry of the first electrode126and/or the substrate120. The cavity122can be an acoustic reflector cavity.

Although some of the BAW devices illustrated and described herein are FBAR devices, any suitable principles and advantages discussed herein can be applied to a solidly mounted resonator (SMR).FIG.5is a cross-sectional view of an example embodiment of a BAW device102, which can have similarities with the BAW device102ofFIG.3. The BAW device102ofFIG.5can be an SMR instead of an FBAR. In the BAW device102ofFIG.5, a solid acoustic mirror can be disposed between the first electrode126and a silicon substrate120. The illustrated acoustic mirror includes acoustic Bragg reflectors. The illustrated acoustic Bragg reflectors include alternating low impedance layers156and high impedance layers158. As an example, the Bragg reflectors can include alternating silicon dioxide layers as low impedance layers156and tungsten layers as high impedance layers158, although other suitable materials could be used. Any other embodiments disclosed herein can use SMR devices. Various other suitable configurations of BAW devices can be used.

FIG.6shows a schematic diagram of a BAW device102, such as the BAW devices ofFIG.4orFIG.5.FIG.6schematically shows the main acoustically active region148, the first or lower electrode126, the second or upper electrode130, lower electrode connection160, an upper electrode connection162, a first or lower-electrode-connected raised frame136, and a second or upper-electrode-connected raised frame138. InFIGS.6,8,10,12, and13, the lower electrode126and the lower-electrode-connected raised frame136are shown in a lighter line weight, whereas the upper electrode130and the upper-electrode-connected raised frame138are shown in a heavier line weight.

With reference toFIGS.1and2, the BAW resonators102a-mcan be arranged as a ladder filter, or a lattice filter, although any suitable type of filter could be used. A filter100, such as a ladder filter, can include multiple resonators coupled in series, and multiple resonators (e.g., shunt resonators) coupled in parallel. In some embodiments, one resonator of the filter100can include multiple resonator sub-elements, which can operate together as a single resonator. The grouped resonators or resonator sub-elements can be configured to at least partially cancel each other's nonlinear responses (e.g., second harmonic responses). For example a first BAW device (e.g., P1A102a, S1A102c, or S3A102i) can produce a first nonlinear response (e.g., a second harmonic response), and a second BAW device (e.g., P1B102b, S1B102d, or S3B102j) can produce a second nonlinear response (e.g., a different second harmonic response) that at least partially counters the first nonlinear response. The second harmonic response for the joint resonator that includes multiple resonator sub-elements can be lower than the second harmonic response of any one of the resonator sub-elements alone. As discussed herein, in some embodiments, the current can flow in opposite directions through the two BAW devices, and/or the voltage polarity across the two BAW devices can be opposite, so that the second harmonic responses of the two BAW devices at least partially cancel. In some embodiments, the filter100can have BAW devices (e.g., P2102k, S4102l, and P3102m) that are not grouped with other resonator sub-elements, and/or are not part of an H2 canceling pair or group. In some embodiments, a resonator can have two resonator sub-elements, as discussed. In other embodiments, a resonator can have more than two resonator sub-elements, such as four, six, or eight, or any suitable number of resonator sub-elements.

By way of example, inFIGS.1and2, the BAW devices P1A102aand P1B102bcan be resonator sub-elements of a single resonator of a filter (e.g., a ladder filter).FIG.7shows a plan view of the BAW devices102aand102b, isolated from other components of the filter100.FIG.8is a schematic illustration of the BAW devices102aand102bas resonator sub-elements coupled together to form a resonator, which can have a reduced non-linear (e.g., second harmonic) response. The BAW devices P1A102aand P1B102bcan function as one resonator with the combined area of P1A102aand P1B102b(e.g., twice the size of a single one of P1A102aor P1B102b). The BAW devices P1A102aand P1B102bcan be coupled in parallel. The BAW devices P1A102aand P1B102bcan be arranged to have opposite voltage polarity. The upper electrode130of a first BAW device HA102acan be electrically coupled to a lower electrode126of a second BAW device P1B102b, such as by a via or other electrical coupling112a. The lower electrode126of the first BAW device HA102acan be electrically coupled to an upper electrode130of a second BAW device P1B102b, such as by a via or other electrical coupling112b. In some embodiments, a voltage across the first resonator sub-element (e.g., BAW device P1A102a) can have substantially the same quantity and an opposite polarity as a voltage across the second resonator sub-element (e.g., BAW device P1B102b). A voltage drop or change from the upper electrode130to the lower electrode126for the first BAW device P1A102aand be substantially the same as a voltage drop or change from the lower electrode126to the upper electrode130of the second BAW device P1B102b. The opposite polarity of the voltages across the BAW devices P1A102aand P1B102bcan cause the nonlinear responses (e.g., second harmonic responses) of the BAW devices P1A102aand P1B102bto at least partially cancel each other.

As another example, inFIGS.1and2, the BAW devices S1A102cand S1B102dcan be resonator sub-elements of a single resonator of a filter (e.g., a ladder filter).FIG.9shows a plan view of the BAW devices S1A102cand S1B102d, isolated from the other components of the filter100.FIG.10shows a schematic illustration of the BAW devices S1A102cand S1B102das resonator sub-elements coupled together to form a resonator, which can have a reduced non-linear (e.g., second harmonic) response. The BAW devices S1A102cand S1B102dcan function as one resonator with half the size of S1A102cor S1B102d(e.g., twice the size of a single one of S1A102cor S1B102d). The BAW devices S1A102cand S1B102dcan be coupled in series. The BAW devices S1A102cand S1B102dcan be arranged to have opposite current directions. The upper electrode130of a first BAW device S1A102ccan be electrically coupled to the upper electrode130of a second BAW device S1B102d. The current can flow into the bottom electrode126and out of the upper electrode130for the first BAW device S1A102c, and the current can flow into the upper electrode130and out of the lower electrode126for the second BAW device S1B102d. The current flow could also go in the opposite direction. In some embodiments, a current through the first resonator sub-element (e.g., BAW device S1A102c) can have substantially the same quantity and an opposite direction as a current through the second resonator sub-element (e.g., BAW device S1B102d). The opposite current through the BAW devices S1A102cand S1B102dcan cause the nonlinear responses (e.g., second harmonic responses) of the BAW devices S1A102cand S1B102dto at least partially cancel each other.

As shown inFIGS.1and2, the BAW devices S3A102iand S3B102jare also coupled in series, similar to S1A and S1B, except that BAW devices S3A102iand S3B102jare coupled by electrically connecting the lower electrodes126, rather than the upper electrodes130. The BAW devices S3A102iand S3B102jcan have opposite current flow, which can cause the nonlinear responses (e.g., second harmonic responses) to at least partially cancel each other. The nonlinear responses (e.g., second harmonic responses) can be reduced for groups of BAW devices by arranging them to have opposite voltages and/or opposite currents.

As shown inFIG.11, in some embodiments, four BAW devices (e.g., BAW devices S2A102e, S2B102f, S2C102g, and S2D102h) can operate as sub-elements of a single resonator (e.g., of a ladder filter).FIG.12shows a schematic illustration of the BAW devices S2A102e, S2B102f, S2C102g, and S2D102h. A first pair of BAW devices S2A102eand S2C102gcan be coupled in series, and a second pair of BAW devices S2B102fand S2D102hcan be coupled in series, and the first pair can be coupled in parallel with the second pair, such as by vias or other electrical connections112cand112d. The nonlinear responses (e.g., second harmonic responses) of the four BAW devices S2A102e, S2B102f, S2C102g, and S2D102hcan at least partially cancel each other. The total nonlinear response (e.g., second harmonic response) of the resonator can be smaller than the nonlinear response (e.g., second harmonic response) of any individual one of the four BAW device resonator sub-elements S2A102e, S2B102f, S2C102g, and S2D102h.

FIG.13shows a schematic illustration of another embodiment with four BAW devices S2A102e, S2B102f, S2C102g, and S2D102h) arranged to operate as sub-elements of a single resonator (e.g., of a ladder filter). A first pair of BAW devices S2A102eand S2B102fcan be coupled in parallel, such as by vias or other electrical connections112eand112f. A second pair of BAW devices S2C102gand S2D102hcan be coupled in parallel, such as by vias or other electrical connections112gand112h. The first pair of BAW devices S2A102eand S2B102fcan be coupled in series with the second pair of BAW devices S2C102gand S2D102h. The bottom electrode126of BAW device S2D102hcan be electrically coupled to the bottom electrode126of the BAW device S2B102f, although various other connections can be used. For example, the upper electrode130of BAW device S2D102hcan be electrically coupled to the upper electrode130of the BAW device S2B102f, or the bottom electrode126of BAW device S2C102gcan be electrically coupled to the bottom electrode126of the BAW device S2A102e, or the upper electrode130of BAW device S2C102gcan be electrically coupled to the upper electrode130of the BAW device S2A102e. The nonlinear responses (e.g., second harmonic responses) of the four BAW devices S2A102e, S2B102f, S2C102g, and S2D102hcan at least partially cancel each other. The total nonlinear response (e.g., second harmonic response) of the resonator can be smaller than the nonlinear response (e.g., second harmonic response) of any individual one of the four BAW device resonator sub-elements S2A102e, S2B102f, S2C102g, and S2D102h. Various other configurations can be used to functionally combine BAW devices102for use as resonators in a filter100.

In the example ofFIG.1, the groups of resonator sub-element BAW devices can have substantially the same shape and substantially the same size. For example, inFIG.1the BAW devices HA102aand P1B102bcan have substantially the same size and shape, and one can be rotated relative to the other. Similarly, the BAW devices S1A and S1B can have substantially the same shape and size, and S2A and S2B can have substantially the same shape and size. Also, each of the four BAW devices S2A102e, S2B102f, S2C102g, and S2D102hcan have substantially the same size and shape, with different rotational orientations. In some implementations, using BAW devices with substantially the same size and shape can facilitate reducing or canceling the nonlinear responses (e.g., second harmonic responses). In some embodiments, pentagons or other polygons with rounded corners can be used, although various suitable shapes could be used for the BAW devices. InFIG.1, the grouped BAW devices can each have the same number of sides, substantially the same side lengths, and substantially the same corner angles.

In the example ofFIG.2, the groups of resonator sub-element BAW devices can have different shapes, while having substantially the same sizes. The different sizes of the BAW devices can enable the BAW devices to be arranged more compactly with less dead-space or with smaller gaps between BAW devices. For example, the arrangement ofFIG.2(e.g., using different shapes for groups of BAW devices) can have an area that is about 25% smaller than the area of the arrangement ofFIG.1(e.g., using the same shapes for groups of BAW devices).

The shapes for the BAW devices can be polygons (e.g., with 3, 4, 5, 6, 7, 8, 10, 12, or more sides) with rounded corners, although any suitable shapes can be used. In some cases, the different shapes can have different numbers of sides. For example, the BAW device S1A102ccan have 5 sides with rounded corners, and the BAW device S1B can have 4 sides with rounded corners. In some cases, the BAW devices can have the same number of sides, but the sides can have different lengths and/or the corners can have different angles. For example, the BAW device HA102aand the BAW device P1B102bcan both have 5 sides with rounded corners, but the sides have different lengths and/or the corners have different angles, so that the resulting shapes are different. If the sides of the grouped BAW devices are listed from shortest to longest, the corresponding sides can differ between the BAW devices by at least about 5%, about 10%, about 15%, about 20%, about 25%, about 30%, about 35%, about 40%, about 45%, about 50%, or more, or any values or ranges between any of these values. If the corner angles of the grouped BAW devices are listed from smallest to largest, the corresponding corner angles can differ between the BAW devices by at least about 5%, about 10%, about 15%, about 20%, about 25%, about 30%, about 35%, about 40%, about 45%, about 50%, or more, or any values or ranges between any of these values.

The cancelation or reduction of the nonlinear responses can depend on the areas and/or perimeters of the resonator elements. To cancel the nonlinear responses for a set of resonator elements, the sizes or resonant areas of the two resonators can be substantially the same. There can be fringing fields at the perimeters of the resonator elements, which can affect the nonlinear responses. Also, changes to the perimeters can change how the current flows through the device and how voltage is applies across a device, which can affect the nonlinear responses. In some cases, the group of resonator elements can all have substantially the same sizes and substantially the same perimeters, even though they can have different shapes, as discussed herein.

The grouped BAW devices (e.g., forming resonator sub-elements of a resonator, such as for a filter) can have substantially the same area, which can facilitate reduction or cancelation of the nonlinear responses of the BAW devices, even though they can have different shapes. For example, the BAW devices HA102aand P1B102bcan have substantially the same area. The BAW devices S1A102cand S1B102dcan have substantially the same area. The BAW devices S3A102iand S3B102jcan have substantially the same area. The BAW devices S2A102e, S2B102f, S2C102g, and S2D102hcan all have substantially the same area. The respective areas can have a difference of not more than about 10%, about 8%, about 6%, about 5%, about 4%, about 3%, about 2%, about 1%, about 0.75%, about 0.5%, about 0.25%, about 0.2%, about 0.15%, about 0.1%, or less, or any values or ranges between any of these values. The area that is substantially the same for the BAW devices can be the active area134, as shown inFIGS.3and5, for example. The area that is substantially the same for the BAW devices can be the center portion or the main acoustically active region148(e.g., between the raised frame structures136and138), as shown inFIGS.3and5, for example.

The grouped BAW devices (e.g., forming resonator sub-elements of a resonator, such as for a filter) can have substantially the same perimeter, which can facilitate reduction or cancelation of the nonlinear responses of the BAW devices, even though they can have different shapes. For example, the BAW devices HA102aand P1B102bcan have substantially the same perimeter. The BAW devices S1A102cand S1B102dcan have substantially the same perimeter. The BAW devices S3A102iand S3B102jcan have substantially the same perimeter. The BAW devices S2A102e, S2B102f, S2C102g, and S2D102hcan all have substantially the same perimeter. The respective perimeters can have a difference of not more than about 10%, about 8%, about 6%, about 5%, about 4%, about 3%, about 2%, about 1%, about 0.75%, about 0.5%, about 0.25%, about 0.2%, about 0.15%, about 0.1%, or less, or any values or ranges between any of these values. The perimeter that is substantially the same for the BAW devices can be the perimeter around an active area134(e.g., outside of the raised frame structures136and138), and/or the perimeter around the center portion or the main acoustically active region148(e.g., inside of the raised frame structures136and138).

The grouped BAW devices (e.g., forming resonator sub-elements of a resonator, such as for a filter) can different shapes, but substantially the same areas for the corresponding raised frame structures136,138. The respective areas of the corresponding raised frame structures136,138can have a difference of not more than about 10%, about 8%, about 6%, about 5%, about 4%, about 3%, about 2%, about 1%, about 0.75%, about 0.5%, about 0.25%, about 0.2%, about 0.15%, about 0.1%, or less, or any values or ranges between any of these values. The corresponding raised frame structures136,138can have substantially the same widths150,152. The respective widths150,152of the corresponding raised frame structures136,138can have a difference of not more than about 10%, about 8%, about 6%, about 5%, about 4%, about 3%, about 2%, about 1%, about 0.75%, about 0.5%, about 0.25%, about 0.2%, about 0.15%, about 0.1%, or less, or any values or ranges between any of these values. The corresponding raised frame structures136,138can have substantially the same lengths150,152(e.g., taken along the perimeters of the BAW device or outside edges of the raised frame structures136,138). The respective lengths of the corresponding raised frame structures136,138can have a difference of not more than about 10%, about 8%, about 6%, about 5%, about 4%, about 3%, about 2%, about 1%, about 0.75%, about 0.5%, about 0.25%, about 0.2%, about 0.15%, about 0.1%, or less, or any values or ranges between any of these values.

The corresponding raised frame structures136,138for grouped BAW devices (e.g., that are coupled upper electrode130to upper electrode130as shown inFIGS.9and10, or that are coupled lower electrode126to lower electrode126) can be the first or lower-electrode-connected raised frame136of a first BAW device corresponding to the first or lower-electrode-connected raised frame136of the second BAW device, and/or the second or upper-electrode-connected raised frame138of the first BAW device corresponding to the second or upper-electrode-connected raised frame138of the second BAW device. For example, inFIGS.2,11, and12, the BAW devices S2A102eand S2C102gcan have substantially the same lengths for their respective first or lower-electrode-connected raised frames136. The BAW devices S2A102eand S2C102gcan also have substantially the same lengths for their respective second or upper-electrode-connected raised frames138. One or more of the dimensional features can match between the first raised frame structures136of the BAW devices (e.g., periodic speckle pattern or light-line-weight features matched with periodic speckle pattern or light-line-weight features). One or more of the dimensional features can match between the second raised frame structures138of the BAW devices (e.g., irregular speckle pattern or heavy-line-weight features matched with irregular speckle pattern or heavy-line-weight features). By way of another example, inFIGS.2,9, and10, the first or lower-electrode-connected raised frame136of the BAW device S1A102cand the first or lower-electrode-connected raised frame136of the BAW device S1B102dcan have substantially the same areas or lengths, and/or the second or upper-electrode-connected raised frame138of the BAW device S1A102cand the second or upper-electrode-connected raised frame138of the BAW device S1B102dcan have substantially the same areas or lengths. The corresponding raised frame areas and/or lengths can be substantially the same, or can vary by the amounts discussed herein.

The corresponding raised frame structures136,138for grouped BAW devices (e.g., that are coupled upper electrode130to lower electrode126, such as through electrical coupling(s)112aand/or112b, as shown inFIGS.7and8) can be the first or lower-electrode-connected raised frame136of a first BAW device corresponding to the second or upper-electrode-connected raised frame138of the second BAW device, and/or the second or upper-electrode-connected raised frame138of the first BAW device corresponding to the first or lower-electrode-connected raised frame136of the second BAW device. Thus, in some cases, one or more of the dimensional features can be matched for opposite raised frame structures136,138for the two BAW devices (e.g., irregular speckle pattern or heavy-line-weight features matched with periodic speckle pattern or light-line-weight features). By way of example, inFIGS.2,7, and8, the first or lower-electrode-connected raised frame136of the BAW device P1A102aand the second or upper-electrode-connected raised frame138of the BAW device P1B102bcan have substantially the same areas or lengths, and/or the second or upper-electrode-connected raised frame138of the BAW device P1A102aand the first or lower-electrode-connected raised frame136of the BAW device P1B102bcan have substantially the same areas or lengths. InFIGS.2,11, and12, the BAW devices S2A102eand S2B102fare coupled bottom electrode126to top electrode130, and can have substantially the same lengths or areas for their respective first and second raised frames136and138. The lower-electrode-connected raised frame136of BAW device S2A can have substantially the same length and/or area as the upper-electrode-connected raised frame138of BAW device S2B. The upper-electrode-connected raised frame138of BAW device S2A can have substantially the same length and/or area as the lower-electrode-connected raised frame136of BAW device S2B. The BAW devices S2C102gand S2D102hcan also have substantially the same lengths or areas for their respective first and second raised frames136and138. The lower-electrode-connected raised frame136of BAW device S2C can have substantially the same length and/or area as the upper-electrode-connected raised frame138of BAW device S2D. The upper-electrode-connected raised frame138of BAW device S2C can have substantially the same length and/or area as the lower-electrode-connected raised frame136of BAW device S2D. The corresponding raised frame areas and/or lengths can be substantially the same, or can vary by the amounts discussed herein.

In some embodiments, the first or lower-electrode-connected raised frame structure136can have substantially the same area, width, and/or length as the second or upper-electrode-connected raised frame structure138on the BAW devices102. In some embodiments, the first or lower-electrode-connected raised frame structure136can have an area, width, and/or length that differs from the area, width, and/or length of the second or upper-electrode-connected raised frame structure138on the BAW devices, such as by about 3%, about 5%, about 7%, about 10%, about 15%, about 20%, about 25%, about 30%, about 35%, about 40%, about 45%, about 50%, or more, or any values or ranges therebetween.

The upper electrode130can be electrically connected to the second conductive material142(e.g., a lead or conductive signal path) along an upper electrode connection162, which can have a length. The lower electrode126can be electrically connected to the first conductive material140(e.g., a lead or conductive signal path) along a lower electrode connection160, which can have a length. The lower electrode connection160can have a length that is substantially the same as the length of the corresponding lower-electrode-connected raised frame structure136, and/or the upper electrode connection162can have a length that is substantially the same as the length of the corresponding upper-electrode-connected raised frame structure138, as shown by the dashed lines inFIG.9. The conductive material140and/or142can be formed along a path that approaches the BAW device102and also extends around a portion of the periphery of the BAW device102so that the corresponding lower electrode connection160and/or upper electrode connection162can have a length that is greater than the width along the path that approaches the BAW device102. In some embodiments, the lower electrode connection160can have a length that is less than the length of the corresponding lower-electrode-connected raised frame structure136, and/or the upper electrode connection162can have a length that is less than the length of the corresponding upper-electrode-connected raised frame structure138, as shown by the dashed lines inFIG.4. The conductive material140and/or142can be formed along a path that approaches the BAW device102, and the lower electrode connection160and/or upper electrode connection162can have a length that corresponds to the width of the conductive path where it meets the corresponding electrode126,130.

The grouped BAW devices (e.g., forming resonator sub-elements of a resonator, such as for a filter) can different shapes, but substantially the same lengths for the corresponding electrode connections160,162. The respective lengths of the corresponding electrode connections160,162can have a difference of not more than about 10%, about 8%, about 6%, about 5%, about 4%, about 3%, about 2%, about 1%, about 0.75%, about 0.5%, about 0.25%, about 0.2%, about 0.15%, about 0.1%, or less, or any values or ranges between any of these values. The upper electrode connection162of a first BAW device can have substantially the same length as the upper electrode connection162of the second BAW device (e.g., irregular speckle pattern or heavy-line-weight features matched with irregular speckle pattern or heavy-line-weight features), such as when the conductive material142couples the upper electrodes of the BAW devices. The lower electrode connection160of a first BAW device can have substantially the same length as the lower electrode connection160of the second BAW device (e.g., periodic speckle pattern or light-line-weight features matched with periodic speckle pattern or light-line-weight features), such as when the conductive material140coupled the lower electrodes of the BAW devices. However, in some cases, the upper electrode connection162of a first BAW device can have substantially the same length as the lower electrode connection160of the second BAW device (e.g., irregular speckle pattern or heavy-line-weight features matched with periodic speckle pattern or light-line-weight features), such as when the conductive materials140and142are coupled by an electrical coupling112(e.g., a via or other vertical coupling) so that the BAW devices are coupled upper electrode130to lower electrode126.

When 4 BAW devices are grouped to form a resonator, such as inFIGS.11-13, one or more of the parameters discussed herein can be matched between all 4 of the BAW devices. In other embodiments, a first pair of BAW devices (e.g., S2A and S2C) can have one or more of the first matched parameters, and a second pair of BAW devices (e.g., S2B and S2D) can have one or more second matched parameters, where the first matched parameters do not match the second matched parameters. The arrangement of 4 BAW devices can be a combination of two matched pairs. In some cases, matching all 4 BAW devices can provide improved reduction or cancelation of the nonlinear responses.

The resonator devices disclosed herein can be implemented in acoustic wave filters. In certain applications, the acoustic wave filters can be band pass filters arranged to pass a radio frequency band and attenuate frequencies outside of the radio frequency band. Two or more acoustic wave filters can be coupled together at a common node and arranged as a multiplexer, such as a duplexer.

FIG.14is a schematic diagram of an example of an acoustic wave ladder filter220. The acoustic wave ladder filter220can be a transmit filter or a receive filter. The acoustic wave ladder filter220can be a band pass filter arranged to filter a radio frequency signal. The acoustic wave filter220can include series resonators R1, R3, R5, R7, and R9and shunt resonators R2, R4, R6, and R8coupled between a radio frequency input/output port RFI/O and an antenna port ANT. The radio frequency input/output port RFI/O can be a transmit port in a transmit filter or a receive port in a receive filter. One or more of the illustrated acoustic wave resonators can be a surface acoustic wave resonator in accordance with any suitable principles and advantages discussed herein. An acoustic wave ladder filter can include any suitable number of series resonators and any suitable number of shunt resonators.

An acoustic wave filter can be arranged in any other suitable filter topology, such as a lattice topology or a hybrid ladder and lattice topology. A surface acoustic wave resonator in accordance with any suitable principles and advantages disclosed herein can be implemented in a band pass filter. In some other applications, a surface acoustic wave resonator in accordance with any suitable principles and advantages disclosed herein can be implemented in a band stop filter.

FIG.15is a schematic diagram of an example of a duplexer230. The duplexer230can include a transmit filter231and a receive filter232coupled to each other at an antenna node ANT. A shunt inductor L1can be connected to the antenna node ANT. The transmit filter231and the receive filter232can both be acoustic wave ladder filters in the duplexer230.

The transmit filter131can filter a radio frequency signal and provide a filtered radio frequency signal to the antenna node ANT. A series inductor L2can be coupled between a transmit input node TX and the acoustic wave resonators of the transmit filter131. The illustrated transmit filter131can include acoustic wave resonators T01to T09. One or more of these resonators can be surface acoustic wave resonator in accordance with any suitable principles and advantages disclosed herein. The illustrated receive filter can include acoustic wave resonators R01to R09. One or more of these resonators can be a surface acoustic wave resonator in accordance with any suitable principles and advantages disclosed herein. The receive filter can filter a radio frequency signal received at the antenna node ANT. A series inductor L3can be coupled between the resonator and a receive output node RX. The receive output node RX of the receive filter provides a radio frequency receive signal.

FIG.16is a schematic diagram of a multiplexer235that includes an acoustic wave filter according to an embodiment. The multiplexer235can include a plurality of filters236A to236N coupled together at a common node COM. The plurality of filters can include any suitable number of filters including, for example, 3 filters, 4 filters, 5 filters, 6 filters, 7 filters, 8 filters, or more filters. Some or all of the plurality of acoustic wave filters can be acoustic wave filters. Each of the illustrated filters236A,236B, and236N can be coupled between the common node COM and a respective input/output node RFI/O1, RFI/O2, and RFI/ON.

In some instances, all filters of the multiplexer235can be receive filters. According to some other instances, all filters of the multiplexer235can be transmit filters. In various applications, the multiplexer235can include one or more transmit filters and one or more receive filters. Accordingly, the multiplexer235can include any suitable number of transmit filters and any suitable number of receive filters. Each of the illustrated filters can be band pass filters having different respective pass bands.

The multiplexer235is illustrated with hard multiplexing with the filters236A to236N having fixed connections to the common node COM. In some other applications, one or more of the filters of a multiplexer can be electrically connected to the common node by a respective switch. Any of such filters can include a surface acoustic wave resonator according to any suitable principles and advantages disclosed herein.

A first filter236A can be an acoustic wave filter having a first pass band and arranged to filter a radio frequency signal. The first filter236A can include one or more surface acoustic wave resonators according to any suitable principles and advantages disclosed herein. A second filter236B has a second pass band. In some embodiments, a raised frame structure of one or more surface acoustic wave resonators of the first filter236A can move a raised frame mode of the one or more surface acoustic wave resonators away from the second passband. This can increase a reflection coefficient (Gamma) of the first filter236A in the pass band of the second filter236B. The raised frame structure of the surface acoustic wave resonator of the first filter236A can also move the raised frame mode away from the passband of one or more other filters of the multiplexer235.

In certain instances, the common node COM of the multiplexer235can be arranged to receive a carrier aggregation signal including at least a first carrier associated with the first passband of the first filter236A and a second carrier associated with the second passband of the second filter236B. A multi-layer raised frame structure of a surface acoustic wave resonator of the first filter236A can maintain and/or increase a reflection coefficient of the first filter236A in the second passband of the second filter236B that is associated with the second carrier of the carrier aggregation signal.

The filters236B to236N of the multiplexer235can include one or more acoustic wave filters, one or more acoustic wave filters that include at least one surface acoustic wave resonator with a raised frame structure, one or more LC filters, one or more hybrid acoustic wave LC filters, or any suitable combination thereof.

The acoustic wave resonators disclosed herein can be implemented in a variety of packaged modules. Some example packaged modules will now be discussed in which any suitable principles and advantages of the surface acoustic wave devices disclosed herein can be implemented. The example packaged modules can include a package that encloses the illustrated circuit elements. The illustrated circuit elements can be disposed on a common packaging substrate. The packaging substrate can be a laminate substrate, for example.FIGS.17,18A,18B, and19are schematic block diagrams of illustrative packaged modules according to certain embodiments. Certain example packaged modules can include one or more radio frequency amplifiers, such as one or more power amplifiers and/or one or more low noise amplifiers. Any suitable combination of features of these modules can be implemented with each other. While duplexers are illustrated in the example packaged modules ofFIGS.17,18A, and19, any other suitable multiplexer that includes a plurality of acoustic wave filters coupled to a common node can be implemented instead of one or more duplexers. For example, a quadplexer can be implemented in certain applications. Alternatively or additionally, one or more filters of a packaged module can be arranged as a transmit filter or a receive filter that is not included in a multiplexer.

FIG.17is a schematic block diagram of an example module240that includes duplexers241A to241N and an antenna switch242. One or more filters of the duplexers241A to241N can include any suitable number acoustic wave resonators in accordance with any suitable principles and advantages discussed herein. Any suitable number of duplexers241A to241N can be implemented. The antenna switch242can have a number of throws corresponding to the number of duplexers241A to241N. The antenna switch242can electrically couple a selected duplexer to an antenna port of the module240.

FIG.18Ais a schematic block diagram of an example module250that includes a power amplifier252, a radio frequency switch254, and duplexers241A to241N in accordance with one or more embodiments. The power amplifier252can amplify a radio frequency signal. The radio frequency switch254can be a multi-throw radio frequency switch. The radio frequency switch254can electrically couple an output of the power amplifier252to a selected transmit filter of the duplexers241A to241N. One or more filters of the duplexers241A to241N can include any suitable number of surface acoustic wave resonators in accordance with any suitable principles and advantages discussed herein. Any suitable number of duplexers241A to241N can be implemented.

FIG.18Bis a schematic block diagram of an example module255that includes filters256A to256N, a radio frequency switch257, and a low noise amplifier258according to one or more embodiments. One or more filters of the filters256A to256N can include any suitable number of surface acoustic wave resonators in accordance with any suitable principles and advantages disclosed herein. Any suitable number of filters256A to256N can be implemented. The illustrated filters256A to256N can be receive filters. In some embodiments (not illustrated), one or more of the filters256A to256N can be included in a multiplexer that also includes a transmit filter. The radio frequency switch257can be a multi-throw radio frequency switch. The radio frequency switch257can electrically couple an output of a selected filter of filters256A to256N to the low noise amplifier257. In some embodiments (not illustrated), a plurality of low noise amplifiers can be implemented. The module255can include diversity receive features in certain applications.

FIG.19is a schematic block diagram of an example module260that includes a power amplifier252, a radio frequency switch254, and a duplexer241that includes surface acoustic wave device in accordance with one or more embodiments, and an antenna switch242. The module260can include elements of the module240and elements of the module250.

One or more filters with any suitable number of surface acoustic devices can be implemented in a variety of wireless communication devices.FIG.20Ais a schematic block diagram of an example wireless communication device270that includes a filter273with one or more acoustic wave resonators in accordance with any suitable principles and advantages disclosed herein. The wireless communication device270can be any suitable wireless communication device. For instance, a wireless communication device270can be a mobile phone, such as a smart phone. As illustrated, the wireless communication device270includes an antenna271, a radio frequency (RF) front end272that includes filter273, an RF transceiver274, a processor275, a memory276, and a user interface277. The antenna271can transmit RF signals provided by the RF front end272. The antenna271can provide received RF signals to the RF front end272for processing.

The RF front end272can include one or more power amplifiers, one or more low noise amplifiers, RF switches, receive filters, transmit filters, duplex filters, filters of a multiplexer, filters of a diplexers or other frequency multiplexing circuit, or any suitable combination thereof. The RF front end272can transmit and receive RF signals associated with any suitable communication standards. Any of the acoustic wave resonators disclosed herein can be implemented in filters273of the RF front end272.

The RF transceiver274can provide RF signals to the RF front end272for amplification and/or other processing. The RF transceiver274can also process an RF signal provided by a low noise amplifier of the RF front end272. The RF transceiver274is in communication with the processor275. The processor275can be a baseband processor. The processor275can provide any suitable base band processing functions for the wireless communication device270. The memory276can be accessed by the processor275. The memory276can store any suitable data for the wireless communication device270. The processor275is also in communication with the user interface277. The user interface277can be any suitable user interface, such as a display.

FIG.20Bis a schematic diagram of a wireless communication device280that includes filters273in a radio frequency front end272and second filters283in a diversity receive module282. The wireless communication device280is like the wireless communication device270ofFIG.20A, except that the wireless communication device280also includes diversity receive features. As illustrated inFIG.20B, the wireless communication device280can include a diversity antenna281, a diversity module282configured to process signals received by the diversity antenna281and including filters283, and a transceiver274in communication with both the radio frequency front end272and the diversity receive module282. One or more of the second filters283can include a surface acoustic wave resonator in accordance with any suitable principles and advantages disclosed herein.

Acoustic wave devices disclosed herein can be included in a filter and/or a multiplexer arranged to filter a radio frequency signal in a fifth generation (5G) New Radio (NR) operating band within Frequency Range 1 (FR1). FR1 can from 410 megahertz (MHz) to 7.125 gigahertz (GHz), for example, as specified in a current 5G NR specification. A filter arranged to filter a radio frequency signal in a 5G NR FR1 operating band can include one or more acoustic wave resonators be implemented in accordance with any suitable principles and advantages disclosed herein.

5G NR carrier aggregation specifications can present technical challenges. For example, 5G carrier aggregations can have wider bandwidth and/or channel spacing than fourth generation (4G) Long Term Evolution (LTE) carrier aggregations. Carrier aggregation bandwidth in certain 5G FR1 applications can be in a range from 120 MHz to 400 MHz, such as in a range from 120 MHz to 200 MHz. Carrier spacing in certain 5G FR1 applications can be up to 100 MHz. Acoustic wave resonators as disclosed herein can have improved heat management, in some embodiments.

Any of the embodiments described above can be implemented in association with mobile devices such as cellular handsets. The principles and advantages of the embodiments can be used for any systems or apparatus, such as any uplink wireless communication device, that could benefit from any of the embodiments described herein. The teachings herein are applicable to a variety of systems. Although this disclosure includes some example embodiments, the teachings described herein can be applied to a variety of structures. Any of the principles and advantages discussed herein can be implemented in association with RF circuits configured to process signals in a frequency range from about 30 kHz to 300 GHz, such as in a frequency range from about 450 MHz to 8.5 GHz.

Aspects of this disclosure can be implemented in various electronic devices. Examples of the electronic devices can include, but are not limited to, consumer electronic products, parts of the consumer electronic products such as packaged radio frequency modules, uplink wireless communication devices, wireless communication infrastructure, electronic test equipment, etc. Examples of the electronic devices can include, but are not limited to, a mobile phone such as a smart phone, a wearable computing device such as a smart watch or an ear piece, a telephone, a television, a computer monitor, a computer, a modem, a hand-held computer, a laptop computer, a tablet computer, a microwave, a refrigerator, a vehicular electronics system such as an automotive electronics system, a stereo system, a digital music player, a radio, a camera such as a digital camera, a portable memory chip, a washer, a dryer, a washer/dryer, a copier, a facsimile machine, a scanner, a multi-functional peripheral device, a wrist watch, a clock, etc. Further, the electronic devices can include unfinished products.

Unless the context indicates otherwise, throughout the description and the claims, the words “comprise,” “comprising,” “include,” “including” and the like are to generally be construed in an inclusive sense, as opposed to an exclusive or exhaustive sense; that is to say, in the sense of “including, but not limited to.” Conditional language used herein, such as, among others, “can,” “could,” “might,” “may,” “e.g.,” “for example,” “such as” and the like, unless specifically stated otherwise, or otherwise understood within the context as used, is generally intended to convey that certain embodiments include, while other embodiments do not include, certain features, elements and/or states. The word “coupled”, as generally used herein, refers to two or more elements that may be either directly connected, or connected by way of one or more intermediate elements. Likewise, the word “connected”, as generally used herein, refers to two or more elements that may be either directly connected, or connected by way of one or more intermediate elements. Additionally, the words “herein,” “above,” “below,” and words of similar import, when used in this application, shall refer to this application as a whole and not to any particular portions of this application. Where the context permits, words in the above Detailed Description using the singular or plural number may also include the plural or singular number respectively. The word “or” in reference to a list of two or more items, that word covers all of the following interpretations of the word: any of the items in the list, all of the items in the list, and any combination of the items in the list.