Bulk acoustic wave resonance structure

Abstract

The embodiment of the utility model provides a bulk acoustic wave resonance structure. The bulk acoustic wave resonance structure comprises a substrate; the first electrode layer, the piezoelectric layer and the second electrode layer are arranged on the substrate; the insertion layer is arranged in the piezoelectric layer, and at least part of the insertion layer is located in the active region of the bulk acoustic wave resonance structure; wherein the thickness of the insertion layer is smaller than that of the piezoelectric layer; the material of the insertion layer is different from that of the piezoelectric layer.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of semiconductors, and particularly to a bulk acoustic wave resonator structure. Background Art

[0002] With the development of mobile communication technology, radio frequency devices are becoming more miniaturized. Bulk acoustic wave resonators have the advantages of small size and high quality factor (Q value), and are often used in filters or duplexers. In mobile terminals, multiple frequency bands are used simultaneously, which requires filters or duplexers to have steeper skirts and smaller insertion losses. Therefore, it has become an urgent problem to improve the Q value of bulk acoustic wave resonators to achieve steep skirts and small insertion losses. Utility Model Content

[0003] In view of this, the embodiments of the present application provide a bulk acoustic wave resonator structure, which includes: a substrate; a first electrode layer, a piezoelectric layer, and a second electrode layer disposed on the substrate; an insertion layer disposed within the piezoelectric layer, and at least a part of the insertion layer is located within the active region of the bulk acoustic wave resonator structure; wherein, the thickness of the insertion layer is less than the thickness of the piezoelectric layer; and the material of the insertion layer is different from the material of the piezoelectric layer.

[0004] In some embodiments, the insertion layer spans across the active region and the non-active region of the bulk acoustic wave resonator structure.

[0005] In some embodiments, the distance range between the outer edge of the insertion layer and the edge of the active region is greater than 0 μm and less than or equal to 3.2 μm.

[0006] In some embodiments, the insertion layer is disposed within the active region.

[0007] In some embodiments, the distance range between the outer edge of the insertion layer and the edge of the active region is 0 μm to 2.0 μm.

[0008] In some embodiments, the insertion layer is disposed in contact with the first electrode layer or the second electrode layer.

[0009] In some embodiments, within the longitudinal cross-section of the insertion layer, the angle range between at least a part of the side edge of the insertion layer and the bottom edge of the insertion layer is 30° to 150°.

[0010] In some embodiments, the insertion layer is disposed in contact with the second electrode layer; wherein, the angle range is 30° to 60°.

[0011] In some embodiments, there is a first spacing between the upper surface of the insertion layer and the piezoelectric layer, and a second spacing between the lower surface of the insertion layer and the piezoelectric layer; the first spacing is substantially the same as the second spacing; wherein, the angle range is 75° to 105°.

[0012] In some embodiments, the ratio of the thickness of the piezoelectric layer to the thickness of the insertion layer ranges from greater than 1 to less than or equal to 5.

[0013] In some embodiments, the thickness of the piezoelectric layer ranges from 600 nm to 1000 nm; the thickness of the insertion layer ranges from 100 nm to 300 nm.

[0014] In some embodiments, the width of the insertion layer ranges from 3.0 μm to 5.0 μm.

[0015] In some embodiments, the material of the insertion layer is a metallic material or a dielectric material.

[0016] In some embodiments, the material of the insertion layer includes molybdenum or silicon dioxide; the material of the piezoelectric layer includes aluminum nitride or scandium-doped aluminum nitride.

[0017] In some embodiments, the insertion layer is disposed around the active region discontinuously or continuously.

[0018] In some embodiments, the insertion layer includes a first part and a second part; the first part and the second part are located at different positions in the direction of surrounding the active region; there is a third spacing between the first part and the upper surface of the piezoelectric layer, and a fourth spacing between the first part and the lower surface of the piezoelectric layer; there is a fifth spacing between the second part and the upper surface of the piezoelectric layer, and a sixth spacing between the second part and the lower surface of the piezoelectric layer; wherein, the third spacing is different from the fifth spacing, and / or the fourth spacing is different from the sixth spacing.

[0019] In each embodiment of the present application, the insertion layer is within the piezoelectric layer, and at least a part of the insertion layer is located within the active region of the bulk acoustic wave resonator structure. The insertion layer can inhibit the propagation of the lateral wave from the active region to the non-active region, limit the energy within the active region, that is, can attenuate the lateral wave, so that the energy is concentrated in the longitudinal wave within the active region, achieving the effect of eliminating the transverse parasitic mode and increasing the Q value. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 A schematic cross-sectional view of a bulk acoustic wave resonator structure as a comparative example;

[0021] Figure 2 A schematic cross-sectional view of the first bulk acoustic wave resonator structure provided by the embodiment of the present application;

[0022] Figure 3 A schematic cross-sectional view of the second bulk acoustic wave resonator structure provided by the embodiment of the present application;

[0023] Figure 4A 、 Figure 4B and Figure 4CSchematic cross-sectional views one, two, and three of a bulk acoustic wave resonator structure in which, when the upper surface of the insertion layer coincides with the upper surface of the piezoelectric layer, the angle alpha between the side edge and the bottom edge of the insertion layer is different, and the distance OVL between the outer edge of the insertion layer and the edge of the active region is different;

[0024] Figure 4D and Figure 4E and Figure 4F Schematic views one, two, and three of test results of preferred cases of different angles alpha and preferred cases of different distances OVL when the upper surface of the insertion layer coincides with the upper surface of the piezoelectric layer;

[0025] Figure 5A 、 Figure 5B and Figure 5C Schematic cross-sectional views one, two, and three of a bulk acoustic wave resonator structure in which there are gaps between the upper surface of the insertion layer and the upper surface of the piezoelectric layer and between the lower surface of the insertion layer and the lower surface of the piezoelectric layer, and the angle alpha between the side edge and the bottom edge of the insertion layer is different, and the distance OVL between the outer edge of the insertion layer and the edge of the active region is different;

[0026] Figure 5D 、 Figure 5E and Figure 5F Schematic views one, two, and three of test results of preferred cases of different angles alpha and preferred cases of different distances OVL when there are gaps between the upper surface of the insertion layer and the upper surface of the piezoelectric layer and between the lower surface of the insertion layer and the lower surface of the piezoelectric layer;

[0027] Figure 6A 、 Figure 6B and Figure 6C Schematic cross-sectional views one, two, and three of a bulk acoustic wave resonator structure in which the lower surface of the insertion layer coincides with the lower surface of the piezoelectric layer, and the angle alpha between the side edge and the bottom edge of the insertion layer is different, and the distance OVL between the outer edge of the insertion layer and the edge of the active region is different;

[0028] Figure 6D and Figure 6E Schematic views one and two of test results of preferred cases of different angles alpha and preferred cases of different distances OVL when the lower surface of the insertion layer coincides with the lower surface of the piezoelectric layer;

[0029] Figure 7A 、 Figure 7B and Figure 7C Schematic views one, two, and three of the first part and the second part of the insertion layer having different sizes; Detailed implementation mode

[0030] The technical solution of the present application will be further elaborated in detail below in conjunction with the accompanying drawings and embodiments. Although exemplary implementation methods of the present application are shown in the drawings, it should be understood that the present application can be implemented in various forms and should not be limited by the implementation manners described herein. On the contrary, these implementation manners are provided to enable a more thorough understanding of the present application and to be able to fully convey the scope of the present application to those skilled in the art.

[0031] In the following paragraphs, the present application will be described more specifically by way of example with reference to the accompanying drawings. According to the following description, the advantages and features of the present application will be clearer. It should be noted that the drawings are all in a very simplified form and use non-precise scales, only for the purpose of facilitating and clearly assisting in explaining the purpose of the embodiments of the present application.

[0032] In the embodiments of the present application, terms such as "first", "second", etc. are used to distinguish similar objects and do not necessarily need to describe a specific order or sequence.

[0033] It should be noted that the technical solutions described in the embodiments of the present application can be arbitrarily combined without conflict.

[0034] The main parameters of a bulk acoustic wave resonator include the electromechanical coupling coefficient (Kt 2 ), Q value, etc. Keeping the Kt of the resonator 2 relatively large while also increasing the Q value of the resonator is crucial in filter design. A higher global quality factor Q value (affecting the series Qs value and the parallel Qp value) among multiple resonators in an acoustic wave device means less energy loss in the acoustic wave device and better device performance. Selecting appropriate Qs values (affecting series) and Qp values (affecting parallel) is crucial in the design of acoustic wave devices. For an acoustic wave device with multiple series resonators, a high Qs value needs to be used, and for an acoustic wave device with multiple parallel resonators, a high Qp value needs to be used.

[0035] According to the connection manner of multiple resonators in the circuit of an acoustic wave device, setting appropriate parameters of the resonator structure to make the global quality factor Q value (affecting the series Qs value and the parallel Qp value) among multiple resonators in the acoustic wave device higher is of practical significance.

[0036] When a bulk acoustic wave resonator is excited by an electric field, longitudinal waves and lateral waves will be generated simultaneously. The existence of lateral waves will affect the energy of the main longitudinal waves. Therefore, one way to increase the Q value of a bulk acoustic wave resonator is to suppress lateral waves, prevent lateral waves from propagating from the active region to the external region, and reduce energy leakage.

[0037] In some embodiments, by disposing an insertion layer within the piezoelectric layer of a bulk acoustic wave resonator (hereinafter also referred to as a bulk acoustic wave resonant structure), the lateral wave propagation to the external region can be suppressed, the energy can be confined within the active region, the parasitic resonance can be reduced, and the Q value can be increased.

[0038] In the present application, within the piezoelectric layer of the bulk acoustic wave resonant structure, the insertion layer located at the edge of the active region of the bulk acoustic wave resonant structure can attenuate the lateral wave, enabling the energy to be concentrated in the longitudinal wave within the active region, achieving the effect of eliminating or reducing the transverse parasitic mode and increasing the Q value.

[0039] Figure 1 FIG. is a schematic cross-sectional view of a bulk acoustic wave resonant structure as a comparative example. Figure 2 FIG. is a schematic cross-sectional view of the first bulk acoustic wave resonant structure provided by an embodiment of the present application. Figure 3 FIG. is a schematic cross-sectional view of the second bulk acoustic wave resonant structure provided by an embodiment of the present application.

[0040] Reference Figure 1 , for the comparative example, the insertion layer 106 is disposed on the second electrode layer 105 and is located within the active region, and the outer edge of the insertion layer 106 of the comparative example coincides with the outer edge of the active region.

[0041] Reference Figure 2 and Figure 3 , for the bulk acoustic wave resonant structures provided by the embodiments of the present application, the insertion layer 106 is disposed within the piezoelectric layer 104, and at least a part of the insertion layer 106 is located within the active region. For example, Figure 2 as shown, the insertion layer 106 is entirely located within the active region, Figure 3 as shown, the insertion layer 106 straddles the active region and the non-active region.

[0042] In this article, the term "outer edge" can be understood as the side of the component / structure / layer of the bulk acoustic wave resonant structure that is far from the center of the active region. For example, Figure 2 and Figure 3 as shown, the outer edge edg1 of the insertion layer 106 can be understood as the side of the insertion layer 106 that is far from the center of the active region. Correspondingly, the inner edge edg2 of the insertion layer 106 can be understood as the side of the insertion layer 106 that is close to the center of the active region.

[0043] Reference Figure 2 and Figure 3 , an embodiment of the present application provides a bulk acoustic wave resonant structure, which includes: a substrate 101; a first electrode layer 103, a piezoelectric layer 104, and a second electrode layer 105 disposed on the substrate 101; an insertion layer 106 disposed within the piezoelectric layer 104, and at least a part of the insertion layer 106 is located within the active region of the bulk acoustic wave resonant structure; wherein, the thickness of the insertion layer 106 is less than the thickness of the piezoelectric layer 104; the material of the insertion layer 106 is different from the material of the piezoelectric layer 104.

[0044] To facilitate an intuitive description of the relative positional relationship between the insertion layer 106 and the first electrode layer 103, the piezoelectric layer 104, and the second electrode layer 105, other components / structures / layers of the bulk acoustic wave resonator structure are not shown in the cross-sectional schematic diagram. For example, the lead-out structure of the first electrode layer 103 (which can be referred to as the first electrode lead) and the lead-out structure of the second electrode layer 105 (which can be referred to as the second electrode lead) are not shown in the cross-sectional schematic diagram (such as Figure 2 and Figure 3 ). Additionally, the bulk acoustic wave resonator structures shown in the cross-sectional schematic diagrams in this application are merely examples of the embodiments of this application and are not used to limit the characteristics of the bulk acoustic wave resonator structures in the embodiments of this application. Other examples of the bulk acoustic wave resonator structures in the embodiments of this application are also shown in the subsequent embodiments.

[0045] In practical applications, the constituent material of the substrate 101 may include silicon (Si), germanium (Ge), etc.

[0046] The first electrode layer 103 can be referred to as the lower electrode. Correspondingly, the second electrode layer 105 can be referred to as the upper electrode, and electrical energy can be applied to the bulk acoustic wave resonator structure through this upper electrode and lower electrode. The constituent materials of the first electrode layer 103 and the second electrode layer 105 can be the same and can specifically include: aluminum (Al), molybdenum (Mo), ruthenium (Ru), iridium (Ir), or platinum (Pt), etc.

[0047] The piezoelectric layer 104 can generate vibrations according to the inverse piezoelectric effect, convert the electrical signal applied to the first electrode layer 103 and the second electrode layer 105 into an acoustic wave signal, and achieve the conversion of electrical energy into mechanical energy. In practical applications, the constituent material of the piezoelectric layer 104 can include: piezoelectric materials such as aluminum nitride, zinc oxide, lithium tantalate, etc.; it can also be a piezoelectric material doped with rare earth elements, and the rare earth elements such as scandium, yttrium, magnesium, titanium, erbium, etc.

[0048] The reflection structure 102 is used to reflect the acoustic wave signal. When the acoustic wave signal generated by the piezoelectric layer 104 propagates towards the reflection structure 102, the acoustic wave signal can be reflected at the interface where the first electrode layer 103 and the reflection structure 102 contact, so that the acoustic wave signal is reflected back into the piezoelectric layer 104.

[0049] Here, the active region includes the region where the reflection structure 102, the first electrode layer 103, the piezoelectric layer 104, and the second electrode layer 105 overlap along the third direction (such as Figure 2 and Figure 3 the active region shown); the third direction is the direction perpendicular to the surface of the substrate 101.

[0050] An insertion layer 106 is disposed within the piezoelectric layer 104, and at least a portion of the insertion layer is located within the active region of the bulk acoustic wave resonator structure. Details such as the relative positional relationship between the insertion layer 106, the first electrode layer 103, the piezoelectric layer 104, and the second electrode layer 105, the shape of the insertion layer 106, the size of the insertion layer 106, and the material of the insertion layer 106 are described in detail below.

[0051] Figure 2 and Figure 3 The bulk acoustic wave resonator structure shown is only an example provided by this application. In practical applications, according to the different forms of the reflection structure 102, it can be specifically divided into: the first type of cavity-type film bulk acoustic wave resonator (FBAR), the second type of cavity-type FBAR, the solid mounted resonator (SMR)-type resonator structure, etc. And the solution provided by the implementation of this application can be applied to the above different types of bulk acoustic wave resonator structures.

[0052] In some embodiments, when the bulk acoustic wave resonator structure includes the first type of cavity-type FBAR, the reflection structure 102 includes a first cavity formed between the upward protrusion of the first electrode layer 103 and the surface of the substrate 101.

[0053] In some embodiments, when the bulk acoustic wave resonator structure includes the second type of cavity-type FBAR, the reflection structure 102 includes a second cavity formed by the downward depression of the surface of the substrate and the first electrode layer 103.

[0054] In some embodiments, when the bulk acoustic wave resonator structure includes an SMR resonator structure, the reflection structure 102 includes a plurality of first dielectric layers and second dielectric layers with different acoustic impedances and arranged alternately in a stacked manner.

[0055] It should be noted that the reflection structure 102 can be a cavity or a solid structure. When the reflection structure 102 is a cavity, the reflection structure 102 includes a first cavity or a second cavity; when the reflection structure 102 is a solid structure, the reflection structure 102 includes a plurality of first dielectric layers and second dielectric layers arranged alternately in a stacked manner. Exemplarily, here and below, the description is made with the reflection structure 102 including a first cavity formed between the upward protrusion of the first electrode layer 103 and the surface of the substrate 101.

[0056] It should be noted that the first direction is orthogonal to the second direction and both are parallel to the surface of the substrate 101, and the third direction is the direction perpendicular to the surface of the substrate 101. The first direction can also be understood as the direction from the edge (or non-active region) of the active region to the middle of the active region. The third direction can be understood as the stacking direction of the first electrode layer 103, the reflection structure 102, the piezoelectric layer 104, and the second electrode layer 105 on the substrate 101.

[0057] Reference Figure 3 In some embodiments, the insertion layer 106 spans the active region and the non-active region of the bulk acoustic wave resonator structure. The insertion layer 106 spanning the active region and the non-active region can be understood as the outer edge edg1 of the insertion layer 106 being located within the non-active region and the inner edge edg2 being located within the active region.

[0058] Reference Figure 3 In some embodiments, the distance OVL between the outer edge of the insertion layer 106 and the edge of the active region ranges from greater than 0 μm to less than or equal to 3.2 μm. Preferably, the distance OVL ranges from 2.9 μm to 3.0 μm. For example, when the insertion layer 106 spans the active region and the non-active region, the value of the distance OVL is 2.9 μm or 3.0 μm.

[0059] It should be noted that the outer edge edg1 of the insertion layer 106 being located within the non-active region can be indicated by a negative value of the distance OVL. For example, a value of the distance OVL of -3.0 μm indicates that the outer edge of the insertion layer 106 is outside the active region and the distance OVL between the outer edge of the insertion layer 106 and the edge of the active region is 3.0 μm.

[0060] When determining the value of the distance OVL, the outer edge of the insertion layer 106 can be understood as the outer edge of the top surface of the insertion layer 106. For example, reference Figure 4A When determining the value of the distance OVL, when the cross-section of the insertion layer 106 is a regular trapezoid, the distance between the outer edge corresponding to the top side (or the short side) of the regular trapezoid and the outer edge of the active region is the distance OVL of the insertion layer 106; reference Figure 4B When determining the value of the distance OVL, when the cross-section of the insertion layer 106 is an inverted trapezoid, the distance between the outer edge corresponding to the top side (or the long side) of the inverted trapezoid and the outer edge of the active region is the distance OVL of the insertion layer 106.

[0061] Reference Figure 2 In some embodiments, the insertion layer 106 is disposed within the active region. The insertion layer 106 being disposed within the active region can be understood as both the outer edge edg1 and the inner edge edg2 of the insertion layer 106 being located within the active region.

[0062] Reference Figure 2 In some embodiments, the distance OVL between the outer edge of the insertion layer 106 and the edge of the active region ranges from 0 μm to 2.0 μm. Preferably, the distance OVL ranges from 1.0 μm to 1.7 μm. For example, when the insertion layer 106 is disposed within the active region, the value of the distance OVL is 1.0 μm or 1.1 μm.

[0063] It should be noted that the outer edge edg1 of the insertion layer 106 is located within the active region, and it can be indicated by taking the value of the distance OVL as zero or a positive value. That is, for the case where the outer edge of the insertion layer 106 is inside the active region, it can be indicated by taking the value of the distance OVL as zero or a positive value. For example, when the value of the distance OVL is 1.0 μm, it indicates that the outer edge of the insertion layer 106 is inside the active region and the distance OVL between the outer edge of the insertion layer 106 and the edge of the active region is 1.0 μm. For example, when the value of the distance OVL is zero, it indicates that the outer edge of the insertion layer 106 coincides with the outer edge of the active region, that is, the distance OVL between the outer edge of the insertion layer 106 and the edge of the active region is zero.

[0064] In some embodiments, the insertion layer 106 is disposed in contact with the first electrode layer 103 or the second electrode layer 105.

[0065] Reference Figure 4A 、 Figure 4B Or Figure 4C When the insertion layer 106 is disposed in contact with the second electrode layer 105, the upper surface of the insertion layer 106 coincides with the upper surface of the piezoelectric layer 104, and there is a spacing between the lower surface of the insertion layer 106 and the lower surface of the piezoelectric layer 104.

[0066] Reference Figure 6A 、 Figure 6B Or Figure 6C When the insertion layer 106 is disposed in contact with the first electrode layer 103, the lower surface of the insertion layer 106 coincides with the lower surface of the piezoelectric layer 104, and there is a spacing between the upper surface of the insertion layer 106 and the upper surface of the piezoelectric layer 104.

[0067] Reference Figure 5A 、 Figure 5B Or Figure 5C In some embodiments, there is a first spacing H1 between the upper surface of the insertion layer 106 and the upper surface of the piezoelectric layer 106, and there is a second spacing H2 between the lower surface of the insertion layer 106 and the lower surface of the piezoelectric layer 104; the first spacing H1 and the second spacing H2 may be the same or different. That is to say, the insertion layer 106 is buried and disposed in the middle of the piezoelectric layer 104.

[0068] In some embodiments, within the longitudinal cross-section of the insertion layer 106, the angle alpha between at least a part of the side of the insertion layer 106 and the bottom edge of the insertion layer 106 ranges from 30° to 150°. Preferably, the angle alpha ranges from 45° to 135°. For example, the angle alpha takes values of 45°, 90°, or 135°.

[0069] Here, the longitudinal cross-section can be understood as the cross-section formed by the first direction and the third direction.

[0070] In the longitudinal section, the side of the insertion layer 106 presents as a straight line. For example, the cross-sectional shape of the insertion layer 106 in the longitudinal section presents a regular trapezoid / inverted trapezoid / square, and the angle range between the waist line (or side) of the regular trapezoid / inverted trapezoid / square and the bottom edge of the insertion layer 106 is 45°, 135°, or 90°.

[0071] In the longitudinal section, the side of the insertion layer 106 presents as a broken line composed of multiple straight lines. For example, the cross-sectional shape of the insertion layer 106 in the longitudinal section presents a broken line composed of multiple straight lines in a staircase (step)-like / quasi-staircase shape, and the angle between each of the multiple straight lines and the bottom edge of the insertion layer 106 is 45°, 90°, or 135°; alternatively, the angle between a part of the straight lines of the broken line and the bottom edge of the insertion layer 106 is 45°, 90°, or 135°, and the angle between the other part of the straight lines of the broken line and the bottom edge of the insertion layer 106 is parallel to the bottom edge of the insertion layer 106, less than 30°, or greater than 135°.

[0072] Reference Figure 4A , in some embodiments, the insertion layer 106 is disposed in contact with the second electrode layer 105; wherein, the angle range is 30° to 60°. Preferably, the angle alpha is 45°. Here, the angle alpha can also be understood as: in the longitudinal section, the angle between the non-contact surface of the second electrode layer 105 and the side of the insertion layer 106, where the non-contact surface can be understood as the surface (or non-fitting surface) of the insertion layer 106 that does not contact the second electrode layer 105.

[0073] Reference Figure 6A , Figure 6B Or Figure 6C , in some embodiments, the insertion layer 106 is disposed in contact with the first electrode layer 103; wherein, the angle range is 45° to 135°. For example, the angle alpha is 45°, 90°, or 135°. Here, the angle alpha can also be understood as: in the longitudinal section, the angle between the contact surface of the first electrode layer 103 and the side of the insertion layer 106, where the contact surface can be understood as the surface (or fitting surface) of the insertion layer 106 that contacts the first electrode layer 103.

[0074] Reference Figure 5C , in some embodiments, there is a first spacing between the insertion layer 106 and the upper surface of the piezoelectric layer 106, and there is a second spacing between the insertion layer 106 and the lower surface of the piezoelectric layer 104; the first spacing is substantially the same as the second spacing; wherein, the angle range is 75° to 105°. Preferably, the angle alpha is 90°.

[0075] In some embodiments, the ratio of the thickness of the piezoelectric layer 104 to the thickness of the insertion layer 106 ranges from greater than 1 to less than or equal to 5. Preferably, the ratio ranges from greater than or equal to 1.5 to less than or equal to 4. For example, the ratio of the thickness of the piezoelectric layer 104 to the thickness of the insertion layer 106 is 2, 2.5, 3, or 3.5.

[0076] In some embodiments, the thickness range of the piezoelectric layer 104 is 600 nm to 1000 nm; the thickness range of the insertion layer 104 is 100 nm to 300 nm. Preferably, the thickness of the piezoelectric layer 104 is 800 nm; the thickness of the insertion layer 104 is 200 nm.

[0077] In some embodiments, the width range of the insertion layer 106 is 3.0 μm to 5.0 μm. Preferably, the width of the insertion layer 106 is 3.5 μm, 4.0 μm, or 4.5 μm.

[0078] It should be noted that the width of the insertion layer 106 can be understood as the width of the portion of the insertion layer 106 having a uniform thickness along the first direction or the average width along the first direction. For example, referring to Figure 4A , Figure 4B , when the cross-section of the insertion layer 106 is trapezoidal, the width of the insertion layer 106 can be understood as the width corresponding to the short side of the trapezoid, or can also be understood as the average width of the trapezoid along the first direction.

[0079] In some embodiments, when the width of the insertion layer 106 is 4.0 μm, the outer edge of the insertion layer 106 is located in the non-active region and the distance OVL between the outer edge of the insertion layer 106 and the edge of the active region is greater than or equal to 4 μm, and when the width of the insertion layer 106 is less than or equal to 4 μm, it can be considered that the insertion layer 106 is located in the non-active region, that is, both the outer edge and the inner edge of the insertion layer 106 are located in the non-active region.

[0080] In some embodiments, the material of the insertion layer 106 is a metal material or a dielectric material. In some embodiments, the material of the piezoelectric layer includes a material with piezoelectric properties.

[0081] In some embodiments, the material of the insertion layer includes molybdenum or silicon dioxide; the material of the piezoelectric layer includes aluminum nitride or scandium-doped aluminum nitride. The material of the insertion layer 106 can use a high acoustic impedance metal material Mo or a dielectric material SiO2, which can reduce the transverse acoustic wave loss, thereby improving the Q value.

[0082] In some embodiments, the insertion layer 106 is arranged around the active region discontinuously or continuously. Arranging the insertion layer around the active region can suppress the transverse parasitic modes and unnecessary higher-order modes of the bulk acoustic wave resonator structure, reduce the leakage of acoustic wave energy, and improve the Q value of the resonator.

[0083] In some embodiments, the insertion layer includes a first part and a second part; the first part and the second part are located at different positions in the direction around the active region; there is a third spacing between the first part and the upper surface of the piezoelectric layer, and a fourth spacing between the first part and the lower surface of the piezoelectric layer; there is a fifth spacing between the second part and the upper surface of the piezoelectric layer, and a sixth spacing between the second part and the lower surface of the piezoelectric layer; wherein, the third spacing is different from the fifth spacing, and / or, the fourth spacing is different from the sixth spacing.

[0084] Reference Figure 7A 、 Figure 7B Or Figure 7C If the insertion layer includes a plurality of discontinuous parts arranged around the active region, then the first part 1061 and the second part 1062 are two of the plurality of parts. If the insertion layer includes an integral body continuously arranged around the active region, then the first part 1061 and the second part 1062 are two parts at different positions in the integral body.

[0085] Reference Figure 7A As shown in, the upper surface of the first part 1061 coincides with the upper surface of the piezoelectric layer 104, and the third spacing H3 ( Figure 7A not shown) is zero, and the fourth spacing H4 is greater than zero; the upper surface of the second part 1062 coincides with the upper surface of the piezoelectric layer, and the fifth spacing H5 ( Figure 7A not shown) is zero, and the sixth spacing H6 is greater than zero; wherein, the fourth spacing H4 is less than the sixth spacing H6.

[0086] Reference Figure 7B As shown in, the third spacing H3 is greater than zero, and the fourth spacing H4 is greater than zero; the fifth spacing H5 is greater than zero, and the sixth spacing H6 is greater than zero; wherein, the third spacing H3 is less than the fifth spacing H5, and the fourth spacing H4 is less than the sixth spacing H6. In practical applications, the third spacing H3 is the same as the fourth spacing H4, and the fifth spacing H5 is the same as the sixth spacing H6.

[0087] Reference Figure 7B In some embodiments, the third spacing H3 is the same as the fourth spacing H4, and / or, the fifth spacing H5 is the same as the sixth spacing H6.

[0088] Reference Figure 7C As shown in, the lower surface of the first part 1061 coincides with the lower surface of the piezoelectric layer 104, and the fourth spacing H4 ( Figure 7C not shown) is zero, and the third spacing H3 is greater than zero; the lower surface of the second part 1062 coincides with the lower surface of the piezoelectric layer, and the sixth spacing H6 ( Figure 7C not shown) is zero, and the fifth spacing H5 is greater than zero; wherein, the third spacing H3 is less than the fifth spacing H5.

[0089] In the following description, when the distance OVL ranges from -4 μm to 2 μm, analysis tests are performed on angles alpha of 45°, 90°, and 135° at a step of 0.5 μm respectively.

[0090] Although Figure 4A , Figure 4B , Figure 4C , Figure 5A , Figure 5B , Figure 5C , Figure 6A , Figure 6B Or Figure 6C Only one case of the cross-sectional schematic diagram of the bulk acoustic wave resonator structure is shown. During the analysis test, the distance OVL of the insertion layer should not be understood only in the case shown in the figure, but should be understood as varying within the range of -4 μm to 2 μm. For example, Figure 4A It shows that the insertion layer of the bulk acoustic wave resonator structure is located within the active region (the distance OVL of the insertion layer takes a positive value). During the analysis test, it can also be understood that the insertion layer is located across the active region and the non-active region (the distance OVL of the insertion layer takes a negative value).

[0091] Refer to Figures 4A to 4F , when the distance OVL ranges from -4 μm to 2 μm, analysis tests are performed on angles alpha of 45°, 90°, and 135° at a step of 0.5 μm respectively. It is found through the test: Refer to Figure 4D , when the distance OVL = 1 μm, the perturbations of the upper semi-circles of the Smith charts (also called reflection charts in this article) of angles alpha of 45°, 90°, and 135° are all the smallest (compared with when the distance OVL takes other values), and the perturbations of the upper semi-circles of the Smith charts of the comparison ratios are smaller.

[0092] Refer to Figure 4D , when the distance OVL = 1 μm, the situation reflected by the Smith chart of angle alpha of 45° is better than the other two angles (angle alpha of 90° and angle alpha of 135°).

[0093] Refer to Figure 4E and Figure 4F , according to the conclusion shown above: when the distance OVL = 1 μm, the effect is relatively good; in order to determine the specific range, when the distance OVL ranges from 0.6 μm to 1.4 μm, simulation tests are performed again at a step of 0.1 μm, and it is found that: when the distance OVL = 1 μm (refer to Figure 4D ) and when the distance OVL = 1.1 μm (refer to Figure 4E ), the perturbations of the upper semi-circles of the Smith charts are the smallest, and the perturbations of the upper semi-circles of the Smith charts of the comparison ratios are smaller. Figure 4F ​

[0094] Reference Figures 5A to 5F When the distance OVL ranges from -4 μm to 2 μm, analysis tests are respectively carried out on angles alpha of 45°, 90°, and 135° with a step of 0.5 μm. It is found through the tests that: Reference Figure 5D When the distance OVL = -3 μm, the upper half circle of the Smith chart has the least disturbance, and the upper half circle of the Smith chart of the comparison ratio has less disturbance.

[0095] Reference Figure 5D When the distance OVL = -3 μm, the situation of the Smith chart with an angle alpha of 90° is better than the other two angles (angle alpha of 45°, angle alpha of 135°).

[0096] Reference Figure 5E and Figure 5F According to the conclusion shown above: When the distance OVL = -3 μm, the effect is relatively good; in order to determine the specific range, when the distance OVL ranges from -3.4 μm to -2.6 μm, simulation tests are carried out again with a step of 0.1 μm. It is found that: When the distance OVL = -3 μm (Reference Figure 5D ) and when the distance OVL = -2.9 μm (Reference Figure 5E ), the upper half circle of the Smith chart has the least disturbance, and the parasitics at low frequencies are relatively less, and the upper half circle of the Smith chart of the comparison ratio has less disturbance. Figure 5F )

[0097] Reference Figures 6A to 6E When the distance OVL ranges from -4 μm to 2 μm, analysis tests are respectively carried out on angles alpha of 45°, 90°, and 135° with a step of 0.5 μm. It is found through the tests that: Reference Figure 6D When the distance OVL = 1.5 μm, the relative disturbance of the upper half circle of the Smith chart is the least.

[0098] Reference Figure 6D When the distance OVL = 1.5 μm, no obvious difference in the Smith chart can be seen at each angle.

[0099] Reference Figure 6E According to the conclusion shown above: When the distance OVL = 1.5 μm, the effect is relatively good; in order to determine the specific range, when the distance OVL ranges from 1.1 μm to 1.9 μm, simulation tests are carried out again with a step of 0.1 μm. It is found that: When the distance OVL = 1.7 (Reference Figure 6D ) Figure 6E ), the upper half circle of the Smith chart has the least disturbance, and the upper half circle of the Smith chart of the comparison ratio has less disturbance.

[0100] Table 1 below is a summary table comparing the test results of each preferred case with those of the comparative example. Among them, the first case of the insertion layer can be understood with reference to Figure 4A 、 Figure 4E and Figure 4F ; The second case of the insertion layer can be understood with reference to Figure 5C 、 Figure 5E and Figure 5F ; The third case of the insertion layer can be understood with reference to Figure 6B and Figure 6E .

[0101] The summary table shows that the angle alpha range of the insertion layer can be selected between 30° and 150°. Compared with the first case and the second case of the insertion layer, the bulk acoustic wave resonator structure with the second case of the insertion layer has better performance, that is, the position of the insertion layer can be selected to be buried in the middle of the piezoelectric layer and span between the active region and the non-active region, and the bulk acoustic wave resonator structure has better performance.

[0102] Table 1

[0103]

[0104] Explanation of the test-related data in each test scheme of this application: 1. The thickness of the insertion layer is 200 nm; 2. The cross-sectional shape of the insertion layer is a regular trapezoid, and the angle between the side and the lower side (or bottom side) of the regular trapezoid is 45°, the upper side length of the trapezoid is 4 μm, and the lower side length of the trapezoid is 4.4 μm; 3. The cross-sectional shape of the insertion layer is a square, that is, the angle between the side and the lower side (or bottom side) of the square is 90°, and the upper side length and the lower side length of the square are both 4 μm; 4. The cross-sectional shape of the insertion layer is an inverted trapezoid, and the angle between the side and the lower side (or bottom side) of the inverted trapezoid is 135°, the upper side length of the inverted trapezoid is 4 μm, and the lower side length is 3.6 μm.

[0105] It should be noted that this application proposes the effectiveness of the insertion layer and the influence law of parameter changes on performance based on theoretical explanations and test results, but the actual preferred parameters need to be selected according to the actual process.

[0106] In each embodiment of this application, the insertion layer is within the piezoelectric layer, and at least part of the insertion layer is located in the active region of the bulk acoustic wave resonator structure. The insertion layer can inhibit the lateral wave from propagating from the active region to the non-active region, limit the energy in the active region, that is, can attenuate the lateral wave, so that the energy is concentrated in the longitudinal wave in the active region, achieving the effect of eliminating the transverse parasitic mode and increasing the Q value.

[0107] Those of ordinary skill in the art can understand that the above-described embodiments are specific examples for implementing the present application. In actual applications, various changes can be made to them in form and details without departing from the spirit and scope of the present application. Any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present application should be covered within the protection scope of the present application.

Claims

1. A bulk acoustic wave resonance structure, characterized in that Comprising: A substrate; A first electrode layer, a piezoelectric layer, and a second electrode layer disposed on the substrate; An insertion layer disposed within the piezoelectric layer, with at least a portion of the insertion layer located within the active region of the bulk acoustic wave resonator structure; wherein the thickness of the insertion layer is less than the thickness of the piezoelectric layer; and the material of the insertion layer is different from the material of the piezoelectric layer.

2. The bulk acoustic wave resonance structure according to claim 1, characterized in that, The insertion layer spans across the active region and the non-active region of the bulk acoustic wave resonator structure.

3. The bulk acoustic wave resonance structure according to claim 2, characterized in that, The distance range between the outer edge of the insertion layer and the edge of the active region is greater than 0 μm and less than or equal to 3.2 μm.

4. The bulk acoustic wave resonant structure according to claim 1, wherein The insertion layer is disposed within the active region.

5. The bulk acoustic wave resonant structure according to claim 4, characterized in that, The distance range between the outer edge of the insertion layer and the edge of the active region is 0 μm to 2.0 μm.

6. The bulk acoustic wave resonance structure according to claim 1, wherein The insertion layer is disposed in contact with the first electrode layer or the second electrode layer.

7. The bulk acoustic wave resonant structure according to claim 1, characterized in that In the longitudinal cross-section of the insertion layer, the angle range between at least a portion of the side edge of the insertion layer and the bottom edge of the insertion layer is 30° to 150°.

8. The bulk acoustic wave resonant structure according to claim 7, characterized in that, The insertion layer is disposed in contact with the second electrode layer; wherein the angle range is 30° to 60°.

9. The bulk acoustic wave resonant structure according to claim 7, wherein, There is a first spacing between the insertion layer and the upper surface of the piezoelectric layer, and a second spacing between the insertion layer and the lower surface of the piezoelectric layer; the first spacing is substantially the same as the second spacing; wherein the angle range is 75° to 105°.

10. The bulk acoustic wave resonance structure according to claim 1, characterized in that The ratio range of the thickness of the piezoelectric layer to the thickness of the insertion layer is greater than 1 and less than or equal to 5.

11. The bulk acoustic wave resonant structure according to claim 10, characterized in that, The thickness range of the piezoelectric layer is 600 nm to 1000 nm; the thickness range of the insertion layer is 100 nm to 300 nm.

12. The bulk acoustic wave resonant structure according to claim 1, characterized in that, The width range of the insertion layer is 3.0 μm to 5.0 μm.

13. The bulk acoustic wave resonance structure according to claim 1, characterized in that, The material of the insertion layer is a metal material or a dielectric material.

14. The bulk acoustic wave resonance structure according to claim 13, wherein The material of the insertion layer includes molybdenum or silicon dioxide; the material of the piezoelectric layer includes aluminum nitride or scandium-doped aluminum nitride.

15. The bulk acoustic wave resonant structure according to claim 1, characterized in that The insertion layer is disposed around the active region discontinuously or continuously.

16. The bulk acoustic wave resonance structure according to claim 15, wherein, The insertion layer includes a first part and a second part; the first part and the second part are located at different positions in the direction of surrounding the active region; there is a third spacing between the first part and the upper surface of the piezoelectric layer, and a fourth spacing between the first part and the lower surface of the piezoelectric layer; there is a fifth spacing between the second part and the upper surface of the piezoelectric layer, and a sixth spacing between the second part and the lower surface of the piezoelectric layer; Wherein, the third spacing is different from the fifth spacing, and / or the fourth spacing is different from the sixth spacing.

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