Bulk acoustic component and method for producing a bulk acoustic component

Abstract

The present invention provides a bulk acoustic component (10) comprising a first electrode (120) and a second electrode (122); a piezo element (100) having at least one first piezoelectric layer (101) which is arranged between the first electrode (120) and the second electrode (122); and at least one high f*Q layer (102) which is arranged next to the first electrode (120) and / or second electrode (122), wherein the high f*Q layer (102) has an intrinsic material damping index (f*Q) above a predetermined minimum value; wherein the first electrode (120) and the second electrode (122) and the piezo element (100) and the high f*Q layer (102) are arranged in a stacked assembly, the bulk acoustic component (10) furthermore comprises a substrate (SB) and an acoustic reflector element (RE), wherein the acoustic reflector element (RE) is arranged in or on the substrate (SB) and the stacked assembly is arranged on the substrate (SB).

Description

[0001] Description

[0002] title

[0003] Volume acoustic component and method for producing a volume acoustic component

[0004] The present invention relates to a volume acoustic component and a method for producing a volume acoustic component.

[0005] State of the art

[0006] Bulk acoustic components can be used as resonators in filters and oscillators, with the operating frequencies being determined by the thickness of the piezoelectric layer and the speed of sound in the piezoelectric material. To achieve higher operating frequencies, the layer thickness can be reduced. However, this can increase the capacitance of the component. If the electromagnetic wave impedance is to be maintained, it may therefore be necessary to simultaneously reduce the component area. However, acoustic energy can be lost at the edge of the component, so that with a reduction in the size of the component, the edge losses can increase quadratically with the operating frequency. In this case, it may be desirable to increase the suitability of bulk acoustic components (BAW) for a range above 10 GHz.

[0007] With each new generation of mobile networks, higher frequencies and greater bandwidths are being released for mobile communications. Passive filter components made from bulk acoustic wave (BAW) resonators have become established in mobile communications due to their small form factor, low insertion losses, and steep slopes. BAW resonators are also used in oscillators. To achieve higher operating frequencies with the resonators, it may be necessary to reduce their energy losses. A dominant source of loss can be inherent material damping. AIN can exhibit comparatively high inherent material damping due to phonon-phonon interaction. The product f*Q of the operating frequency f and the quality factor Q is used as a measure of the inherent material damping. The larger the product, the lower the respective inherent material damping.

[0008] US 2018 / 085787 A1 describes a volume acoustic component.

[0009] Disclosure of the invention

[0010] The present invention provides a volume acoustic component according to claim 1 and a method for producing a volume acoustic component according to claim 12.

[0011] Preferred further training is the subject of the subclaims.

[0012] Advantages of the invention

[0013] The idea underlying the present invention is to provide a volume acoustic component and a method for producing a volume acoustic component, wherein a suitability of the volume acoustic component for operation in high frequency ranges, in particular above 10 GHz, can be improved.

[0014] Advantageously, a higher frequency range can be accessed and at least a portion of the generated acoustic energy can be transferred into a high-f*Q material. This volume acoustic component can provide an alternative technology path for accessing higher frequency ranges.

[0015] According to the invention, the volume acoustic component comprises a first electrode and a second electrode; a piezoelectric element with at least one first piezoelectric layer arranged between the first electrode and the second electrode; and at least one high-f*Q layer arranged adjacent to the first electrode and / or the second electrode, wherein the high-f*Q layer has a material intrinsic damping characteristic f*Q above a predetermined minimum value; wherein the first electrode and the second electrode and the piezoelectric element as well as the high-f*Q layer are arranged in a stack arrangement. The volume acoustic component further comprises a substrate and an acoustic reflector element, wherein the acoustic reflector element is arranged or formed in or on the substrate and the stack arrangement is arranged on the substrate. The substrate can in particular also comprise an insulation layer.

[0016] According to the invention, higher operating frequencies above, for example, 10 GHz can be achieved for volume acoustic components, for example resonators.

[0017] According to a preferred embodiment of the volume acoustic component, this represents an acoustic resonator.

[0018] According to a preferred embodiment of the volume acoustic component, the acoustic reflector element comprises an air cavity in the substrate.

[0019] According to a preferred embodiment of the volume acoustic component, the acoustic reflector element is an air gap between the substrate-facing electrode and the substrate and / or is an acoustic Bragg reflector on the substrate and / or is arranged in the stacked arrangement. In this way, the loss of acoustic energy into the substrate is reduced, and a high resonator quality can be achieved. According to a preferred embodiment of the volume acoustic component, the invention relates to a material intrinsic damping characteristic with a product of an operating frequency f of the volume acoustic component and a quality factor Q of greater than 3*10 A 13 Hz

[0020] According to a preferred embodiment of the volume acoustic component, the piezoelectric element comprises at least a first piezoelectric layer and a second piezoelectric layer, wherein the first piezoelectric layer and the second piezoelectric layer have different polarities, in particular opposite polarities, and each have a thickness of substantially half an acoustic wavelength. An advantage of this alternately polarized arrangement is that the generated surface charges add together instead of canceling each other out.

[0021] According to a preferred embodiment of the volume acoustic component, the high-f*Q layer is arranged between the first and second electrodes or outside them. This advantageously suppresses unwanted parasitic modes and couples a portion of the acoustic energy into the high-f*Q layer, resulting in a higher resonator quality factor.

[0022] According to a preferred embodiment of the volume acoustic component, an additional high-f*Q layer is present, and the high-f*Q layer and the additional high-f*Q layer border the first electrode and / or the second electrode on both sides of the piezo element. In this way, unwanted parasitic modes are advantageously suppressed and a portion of the acoustic energy is coupled into the high-f*Q layer, resulting in a higher resonator quality factor.

[0023] According to a preferred embodiment of the volume acoustic component, an overlap of the first electrode and the second electrode defines an active region of the volume acoustic component, viewed in a stacking direction on the substrate. The region of the high-f*Q layer can be located within the active region and extend congruently to the contour line of the active region. This allows the acoustic energy to be laterally confined. According to a preferred embodiment of the volume acoustic component, the acoustic reflector element is arranged on the substrate side, integrated into or on the stack arrangement.

[0024] According to a preferred development, several of the previously described volume acoustic resonators together form a volume acoustic filter component

[0025] According to a preferred embodiment of the volume acoustic component, it is designed for operation as a resonator at an acoustic frequency of greater than or equal to 10 GHz.

[0026] The volume acoustic component can also be characterized by the features and advantages mentioned in connection with the process and vice versa.

[0027] The volume acoustic component can be advantageously used for or as volume acoustic resonator component(s), for example as resonators / oscillators, RF filters in the transmit and receive path of a communication system or radar system, gravimetric sensors or others and can relate to or represent MEMS sensors.

[0028] The volume acoustic RF resonator component can thus consist of a substrate; at least one piezoelectric resonator comprising two electrodes, a piezoelectric layer stack and at least one high-f*Q layer, and at least one acoustic reflector arranged on the substrate side, wherein the piezoelectric layer stack is arranged between the electrodes, the high-f*Q layer is arranged directly adjacent to at least one of the electrodes, and the overlap region of the two electrodes defines an active region of the component.

[0029] The acoustic reflector can be an air gap or an acoustic Bragg mirror. Furthermore, the f*Q product of the high-f*Q layer can be greater than 3*10 A 13Hz and the material of the high-f*Q layer can be SiC, diamond, Si, AI2O3, GaN, Si3N4, W or any other material with low intrinsic attenuation.

[0030] The piezo element can be a layer stack of a plurality of piezoelectric layers with alternating opposite polarity and a thickness of half an acoustic wavelength.

[0031] The resonator component (bulk acoustic component) can be configured such that a main mode with essentially at least a multiple of half an acoustic wavelength occurs in the piezoelectric layer stack and essentially a multiple of another half an acoustic wavelength in the high-f*Q layer. The frequency of the main mode can be greater than 10 GHz.

[0032] There may be a capacitive coupling of the electrodes through thick conductor tracks.

[0033] Thus, and among other things, according to the invention, a reduction of acoustic energy losses due to material damping in volume acoustic resonator components and / or an opening up of higher frequency ranges can be advantageously achieved.

[0034] The invention can be used advantageously for volume acoustic resonator components such as resonators / oscillators, RF filters, or others and can relate to MEMS components for RF systems in the mobile radio (filters) or in the radar range (oscillators).

[0035] Advantageously, a high-frequency signal can be fed into the volume acoustic component at a first electrode, and the electromagnetic wave can be converted into an acoustic wave at the first electrode by a piezoelectric (piezo element) and back into an electromagnetic wave at an opposite second electrode. For a given electromagnetic or acoustic frequency, the acoustic wavelength La is determined from the speed of sound cs of the respective layer material: La=cs / f. Only if the layer thickness dp of the piezoelectric layer corresponds to a multiple of half the acoustic wavelength of the converted electromagnetic wave, i.e. dp=(n+ 1Z>)* La for n={0; 1 ; ...}, the incoming signal is transmitted and otherwise reflected. This is referred to as a bulk acoustic resonator, whose important characteristic can be the Q factor of the resonator(s). The larger this factor, the more powerful the component, although the Q factor can be limited by the energy losses. To avoid acoustic energy losses in the vertical direction, acoustic reflectors are used, either in the form of air (FBAR - film bulk acoustic resonator) or acoustic Bragg mirrors (SMR - solidly mounted resonator). However, in order to be able to reach higher operating frequencies with the resonators, the energy losses must be further reduced.

[0036] Material damping can represent a significant energy loss mechanism, with piezoelectrics such as AIN exhibiting comparatively high material damping due to phonon-phonon interactions. The product f*Q of the operating frequency f and the quality factor Q is used as a measure of material damping. For AIN, this material damping index is approximately 2*10 A 13Hz.

[0037] According to the invention, the resonator can therefore be acoustically coupled to a high-f*Q layer, in particular the high-f*Q layer, wherein this high-f*Q layer can be arranged in direct contact with at least one of the electrodes and can have a thickness that corresponds to a multiple of half a wavelength of a resonance wavelength of the piezoelectric high-f*Q layer stack (and / or the piezoelement). The acoustic energy generated in the piezoelectric high-f*Q layer stack (in the piezoelement) is then distributed between the layer stack and the high-f*Q layer. Since the wave energy now resonates partially in the less lossy high-f*Q material and no longer exclusively in the lossy piezoelectric layer stack, lower energy losses occur. Therefore, the resonator can achieve higher Q factors or be designed for higher frequencies. As mentioned above, the f*Q product of the high-f*Q layer can ideally be larger than 3*10。A 13Hz and is thus higher than that of AlN, whereby materials such as SiC, diamond, Si, Al2O3, GaN, Si3N4, W or combinations thereof can be used as materials for the high-f*Q layer.

[0038] The high-f*Q layer can be arranged on one or both sides of the piezoelement (piezoelectric layer stack) directly adjacent to the electrodes. The piezoelement (piezoelectric layer stack) itself can consist of or comprise a plurality of piezoelectric layers with opposite polarity and a thickness of individual layers that essentially corresponds to a multiple of half a wavelength La / 2 of a resonance wavelength of the resonator. In other words, the simplest resonator according to the invention has a (overtone) main mode in the range greater than 10 GHz, in which essentially half an acoustic wavelength in the high-f*Q layer and another half an acoustic wavelength in the piezoelement can oscillate with the electrodes. The thickness of the electrodes is typically in the range less than or equal to La / 5, where La is the acoustic wavelength.

[0039] At such high frequencies, the thickness of the electrodes can be very thin. To avoid ohmic losses through the leads to the electrodes, a capacitive coupling of the electrodes can be provided by thicker conductors. An acoustic decoupling device (i.e., an acoustic mirror) of a predetermined thickness and lateral extension can be provided between the electrodes and the lead (conductor).

[0040] According to a preferred embodiment of the volume acoustic component, an overlap of the first electrode and the second electrode and the high-f*Q layer, viewed in a stacking direction on the substrate, can define an active region with increased lateral acoustic energy confinement of the volume acoustic component.

[0041] According to the invention, the method for producing a volume acoustic component comprises providing S1 a substrate and arranging a first electrode and a second electrode with a piezoelectric element therebetween, which piezoelectric element has at least one first piezoelectric layer, and arranging S2 at least one high-f*Q layer, which is arranged adjacent to the first electrode and / or to the second electrode, wherein the high-f*Q layer has an f*Q product above a predetermined minimum size; wherein the first electrode and the second electrode and the piezoelectric element as well as the high-f*Q layer are arranged in a stack arrangement, wherein an acoustic reflector element is arranged or formed in the substrate or in the layer stack.

[0042] Further features and advantages of embodiments of the invention will become apparent from the following description with reference to the accompanying drawings.

[0043] Short description of the drawings

[0044] The present invention is explained in more detail below with reference to the exemplary embodiments shown in the schematic figures of the drawing.

[0045] They show:

[0046] Fig. 1 is a schematic cross-sectional view of a volume acoustic component according to an embodiment of the present invention;

[0047] Fig. 2 is a schematic cross-sectional view of a volume acoustic component according to a further embodiment of the present invention;

[0048] Fig. 3 is a schematic cross-sectional view of a volume acoustic component according to a further embodiment of the present invention;

[0049] Fig. 4 is a schematic cross-sectional view of a volume acoustic component according to a further embodiment of the present invention;

[0050] Fig. 5 is a schematic cross-sectional view of a volume acoustic component according to a further embodiment of the present invention;

[0051] Fig. 6 is a schematic cross-sectional view of a volume acoustic component according to a further embodiment of the present invention;

[0052] Fig. 7 is a schematic cross-sectional view of a volume acoustic component according to a further embodiment of the present invention; and

[0053] Fig. 8 is a block diagram of method steps of the method for producing a volume acoustic component according to an embodiment of the present invention.

[0054] In the figures, the same reference symbols denote the same or functionally identical elements.

[0055] Fig. 1 shows a schematic cross-sectional view of a volume acoustic component according to an embodiment of the present invention.

[0056] The sectional view shows a schematic side section through the stack arrangement of the volume acoustic component 10 on a substrate SB. The volume acoustic component 10 comprises a first electrode 120 and a second electrode 122; a piezoelectric element 100 with at least one first piezoelectric layer, which is arranged between the first electrode 120 and the second electrode 122; and at least one high-f*Q layer 102, which is arranged adjacent to the second electrode 122, wherein the high-f*Q layer 102 has an f*Q product above a predetermined minimum value; wherein the first electrode 120 and the second electrode 122 and the piezoelectric element 100 as well as the high-f*Q layer 102 are arranged in a stack arrangement. The volume acoustic component 10 further comprises a substrate SB and an acoustic reflector element RE, wherein in the case of Fig.1, the acoustic reflector element RE is introduced into the substrate SB as an air mirror, in other words, as a cavity in the substrate SB, and the stack arrangement is arranged on the substrate SB. The air cavity RE can advantageously be formed in the substrate SB and adjacent to the first electrode 120.

[0057] For this purpose, an overlap of the first electrode 120 and the second electrode 122 may be present, viewed in a stacking direction on the substrate SB, and this may define an active region AB of the volume acoustic component 10. The region of the high-f*Q layer may lie within the active region and extend congruently to the contour line of the active region.

[0058] At least within this active region AB, the volume acoustic component 10 can represent an acoustic resonator. The piezoelectric element 100 can be located between the two electrodes and directly connected to them. The second electrode 122 can be the upper electrode on the piezoelectric element 100 facing away from the substrate and can be electrically contacted by a conductor track there via a via FK through the piezoelectric element 100. The first substrate-facing electrode 120 can be arranged on the substrate SB and extend partially over the air cavity RE so that the air surface can act on this first electrode 120. The air cavity RE can be located partially or completely in the active region AB. The high-f*Q layer 102 can be arranged lying directly on the second electrode 122.

[0059] According to Fig. 1, the volume acoustic component 10 can be an FBAR (film bulk acoustic resonator). On the left side, an acoustic eigenmode SM with associated deflections is shown, which can extend through the layer stack. Opposing stress amplitudes can occur in the piezo element 100 and the high-f*Q layer 102. The thickness of the high-f*Q layer 102 and the piezo element 100 can each be essentially half an acoustic wavelength. Fig. 2 shows a schematic cross-sectional view of a volume acoustic component according to a further embodiment of the present invention.

[0060] The volume acoustic component 10 of Fig. 2 is similar to that of Fig. 1 and differs in that Fig. 2 represents an SMR (solidly mounted resonator) resonator element. Instead of the air cavity of Fig. 1, according to Fig. 2, an acoustic Bragg reflector can be used as a reflector element RE on the substrate side of the stack arrangement and can be located between the substrate SB and the first electrode 120. The reflector element RE can extend laterally on the substrate SB beyond the active region AB and beyond the layer stack. The piezo element 100 does not have a through-contact. The oscillation mode SM shown corresponds to the profile of Fig. 1 and also extends into the multitude of layers of the acoustic Bragg reflector.The acoustic Bragg reflector here consists of three double layers of materials with alternating high and low acoustic impedance, with each of the material layers having an acoustic thickness of essentially an odd quarter wavelength.

[0061] Fig. 3 shows a schematic cross-sectional view of a volume acoustic component according to a further embodiment of the present invention.

[0062] Similar to Fig. 1, Fig. 3 shows an FBAR resonator with an air cavity RE in the substrate SB. The difference from Fig. 1 is that the high-f*Q layer 102 is located between the first electrode 120 facing the substrate and the piezo element 100. The second electrode 122 facing away from the substrate can be in electrical contact with a conductor track on the substrate SB via a web FK, which can be parallel to and outside the layer stack.

[0063] Fig. 4 shows a schematic cross-sectional view of a volume acoustic component according to a further embodiment of the present invention. Similar to Fig. 2, Fig. 4 shows an SMR resonator with a Bragg reflector RE on the substrate SB. The difference from Fig. 2 is that the high-f*Q layer 102 is arranged between the piezoelectric element 100 and the second (upper) electrode 122. In both Fig. 2 and Fig. 4, the piezoelectric element 100 extends laterally beyond the high-f*Q layer 102 and the second electrode 122, and optionally also beyond the active region AB.

[0064] Fig. 5 shows a schematic cross-sectional view of a volume acoustic component according to a further embodiment of the present invention.

[0065] According to Fig. 5, a similar embodiment from Fig. 4 is shown, with the addition that a high-f*Q layer 102a is arranged on top of the second electrode 122. Thus, a high-f*Q layer 102a can be arranged on top of the second electrode 122, and a further high-f*Q layer 102b can be present between the piezo element 100 and the second electrode 122. Both high-f*Q layers 102a, 102b can have the same lateral extent and the same or different material intrinsic damping f*Q. This approach has the advantage that adding the high-f*Q layer 102a outside the electrodes does not lead to any change in the electrical impedance of the resonator component. In other words, the layer thicknesses of the high-f*Q layers 102a, b can be selected such that a size of the component and a quality factor of the resonator component are optimal at constant electrical impedance.

[0066] Fig. 6 shows a schematic cross-sectional view of a volume acoustic component according to a further embodiment of the present invention.

[0067] Fig. 6 shows a variation of Fig. 1, wherein two high-f*Q layers 102a and 102b are located outside the electrodes 120 and 122, respectively. There is an upper high-f*Q layer 102a, which rests on the second electrode 122, and a lower high-f*Q layer 102b, which can rest on the substrate SB, and wherein the first electrode 120 can rest on the lower high-f*Q layer 102b. The lower high-f*Q layer 102b can at least partially cover the air cavity RE. An advantage of this arrangement is its high vertical symmetry. It enables a low temperature response of the resonant frequency, since thermomechanical temperature expansion effects can generate virtually no stress gradients.Furthermore, the high-f*Q layer 102a facing away from the substrate can define a region of increased confinement for acoustic energy by the position of its lateral edge contour lines within or relative to those of the active region, which increases the quality factor of the resonator.

[0068] The piezoelectric element 100 may include at least a first piezoelectric layer 100a and a second piezoelectric layer 100b, wherein the first piezoelectric layer 100a and the second piezoelectric layer 100b may have opposite polarities and each have a thickness of half an acoustic wavelength. The piezoelectric element 100 may extend laterally beyond the upper high-f*Q layer 102a. The lateral extent of the upper high-f*Q layer 102a may define the lateral extent of an active region with increased acoustic energy confinement.

[0069] Fig. 7 shows a schematic cross-sectional view of a volume acoustic component according to a further embodiment of the present invention.

[0070] Fig. 7 shows an arrangement similar to the arrangement in Fig. 2, with the difference that a lower substrate-facing feed line UZ can be located between the Bragg reflector RE and the substrate, which feed line can have a predetermined minimum thickness. Analogously, an upper substrate-facing feed line OZ can be present on the upper side of the stack arrangement, which feed line can also have a predetermined minimum thickness. The two feed lines can be brought to the layer stack from different sides. A predetermined gap SP with a predetermined gap height can be formed between the upper feed line OZ and the high-f*Q layer 102. The gap height can be between 10 nm and 200 nm, for example.The piezoelectric element 100 can be located between the two electrodes 120 and 122 and can have a first piezoelectric layer 100a and a second piezoelectric layer 100b, wherein the first piezoelectric layer 100a and the second piezoelectric layer 100b can have different polarities from one another. The two leads OZ and UZ can each achieve a capacitive coupling of the facing electrode(s) to the respective lead. The high-f*Q layer can have a dielectric constant, which increases the capacitive coupling between the upper lead OZ and the electrode facing away from the substrate. The upper lead OZ is mechanically decoupled from the acoustic oscillation by the gap, and the lower lead by the Bragg mirror, i.e. the mass density of the leads has no effect on the resonant frequency, nor does the material damping of the leads play a role in the quality of the component.The supply lines can therefore be designed with low resistance and of any thickness, independent of the acoustic wavelength of the resonator, so that the electrical attenuation is minimized.

[0071] Fig. 8 shows a block diagram of method steps of the method for producing a volume acoustic component according to an embodiment of the present invention.

[0072] In the method for producing a volume acoustic component, a substrate is provided S1 and a first electrode and a second electrode are arranged with a piezoelectric element therebetween, which piezoelectric element has at least one first piezoelectric layer, and at least one high-f*Q layer is arranged S2, which is arranged adjacent to the first electrode and / or to the second electrode, wherein the high-f*Q layer has a material intrinsic damping above a predetermined minimum value of the f*Q product; wherein the first electrode and the second electrode and the piezoelectric element as well as the high-f*Q layer are arranged in a stack arrangement, wherein an acoustic reflector element is arranged or formed in the substrate or in the layer stack.

[0073] Although the present invention has been fully described above using preferred embodiments, it is not limited thereto but can be modified in many ways.

Claims

Claims 1. Volume acoustic component (10) comprising, - a first electrode (120) and a second electrode (122); - a piezoelectric element (100) having at least one first piezoelectric layer (101) arranged between the first electrode (120) and the second electrode (122); and - at least one high-f*Q layer (102) which is adjacent to the first electrode (120) and / or to the second electrode (122), wherein the high-f*Q layer (102) has a material damping characteristic (f*Q) above a predetermined minimum value; wherein the first electrode (120) and the second electrode (122) and the piezo element (100) as well as the high-f*Q layer (102) are arranged in a stack arrangement, the volume acoustic component (10) further comprises a substrate (SB) and an acoustic reflector element (RE), wherein the acoustic Reflector element (RE) is arranged or formed in or on the substrate (SB) and the stack arrangement is arranged on the substrate (SB).

2. Volume acoustic component (10) according to claim 1, which represents an acoustic resonator.

3. Volume acoustic component (10) according to claim 1 or 2, wherein the acoustic reflector element (RE) comprises an air cavity in the substrate (SB) or is arranged as an acoustic Bragg reflector on the substrate (SB) and / or in the stack arrangement.

4. Volume acoustic component (10) according to one of claims 1 to 3, wherein the material damping characteristic (f*Q) relates to a product of an operating frequency (f) of the volume acoustic component (10) and a quality factor (Q) and f*Q is greater than 3*10 A 13 Hz.

5. Volume acoustic component (10) according to one of claims 1 to 4, wherein the piezoelectric element (100) has at least a first piezoelectric layer (100a, 101) and a second piezoelectric layer (100b), wherein the first piezoelectric layer (100a, 101) and the second piezoelectric layer (100b) have opposite polarities and each have a thickness of half an acoustic wavelength in particular exactly half a wavelength.

6. Volume acoustic component (10) according to one of claims 1 to 5, in which a further high-f*Q layer (102b) is present and the high-f*Q layer (102, 102a) and the further high-f*Q layer (102b) border the first electrode (120) and the second electrode (122) on both sides of the piezo element (100).

7. Volume acoustic component (10) according to one of claims 1 to 6, wherein, viewed in a stacking direction on the substrate (SB), an overlap of the first electrode (120) and the second electrode (122) defines an active region (AB) of the volume acoustic component (10).

8. Volume acoustic component (10) according to one of claims 1 to 7, wherein, viewed in a stacking direction on the substrate (SB), an overlap of the first electrode (120) and the second electrode (122) and the high-f*Q layer defines an active region (AB) with increased lateral acoustic energy confinement of the volume acoustic component (10).

9. Volume acoustic component (10) according to one of claims 1 to 8, wherein the acoustic reflector element (RE) is arranged on the substrate side on or integrated in the stack arrangement.

10. Volume acoustic component (10) according to one of claims 1 to 9, wherein the high-f*Q layer (102) is arranged between the first and second electrodes (120, 122) or outside them.

11. Volume acoustic component (10) according to one of claims 1 to 10, which is designed for operation as a resonator at an acoustic frequency of greater than or equal to 10 GHz.

12. A method for producing a volume acoustic component (10), comprising the steps: - Providing (S1) a substrate (SB) and arranging a first electrode (120) and a second electrode (122) with a piezoelectric element (100) therebetween, which has at least one first piezoelectric layer (101), and - Arranging (S2) at least one high-f*Q layer (102), which is arranged adjacent to the first electrode (120) and / or to the second electrode (122), wherein the high-f*Q layer (102) has a material intrinsic damping characteristic (f*Q) above a predetermined minimum value; wherein the first electrode (120) and the second electrode (122) and the piezo element (100) as well as the high-f*Q layer (102) are arranged in a stack arrangement, wherein an acoustic reflector element (RE) is arranged or formed in the substrate (SB) or in the layer stack.

Images