Passive filter and hybrid filter applying same

Abstract

The invention relates to the technical field of semiconductor devices, in particular to a passive filter and a hybrid filter applying the same. The passive filter comprises a heterogeneous substrate assembly which comprises a supporting substrate, a first dielectric layer and a single crystal film substrate; the first dielectric layer is arranged on the surface of one side of the supporting substrate; the single crystal thin film substrate is arranged on the surface of one side, deviating from the supporting substrate, of the first dielectric layer; the first patterned electrode is arranged on the side, away from the first dielectric layer, of the single crystal thin film substrate, and the first patterned electrode and the heterogeneous substrate assembly at least form a partial circuit structure of an equivalent circuit. The radio frequency loss of the substrate can be reduced, the quality factor of the equivalent circuit is improved, the insertion loss of the passive filter is reduced, the reliability and the integration degree of the device are improved, and the device cost is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor devices, and in particular to a passive filter and a hybrid filter using the passive filter. Background Art

[0002] As semiconductor process technology matures, RF and microwave systems are showing a trend of high-density integration, miniaturization, multi-functions, and low costs. As an important semiconductor passive device, filters need to meet the needs of high-frequency and wide-bandwidth application scenarios while taking into account the above development directions. Therefore, various indicators of filters, such as insertion loss, out-of-band suppression, and bandwidth range, have become crucial.

[0003] In the prior art, integrated passive devices usually use simple circuit elements to build Chebyshev filters to meet the needs of high frequency and wide bandwidth bands. However, circuit elements such as capacitors and inductors have low quality factors at high frequencies, and devices based on silicon substrates will cause high RF losses due to parasitic effects, making the insertion loss of such filters large within the passband and difficult to achieve rapid roll-off of the band edge. Therefore, it is necessary to develop an integrated passive filter that can adapt to high frequency and wide bandwidth band application scenarios to improve the above problems in the prior art. Summary of the invention

[0004] In view of the problems of large loss in the passband, narrow bandwidth range, poor band edge steepness and poor compatibility with silicon-based processes existing in the integrated passive filter in the above-mentioned prior art, the present invention provides a passive filter and a hybrid filter using the same.

[0005] The specific technical solutions of the present invention are as follows:

[0006] The present invention provides a passive filter, which comprises: a heterogeneous substrate assembly, comprising a supporting substrate, a first dielectric layer and a single crystal thin film substrate; the first dielectric layer is arranged on a side surface of the supporting substrate; the single crystal thin film substrate is arranged on a side surface of the first dielectric layer away from the supporting substrate; a first patterned electrode, the first patterned electrode is arranged on a side of the single crystal thin film substrate away from the first dielectric layer, and the first patterned electrode and the heterogeneous substrate assembly at least form a partial circuit structure of an equivalent circuit.

[0007] In a possible implementation manner, the equivalent circuit includes an equivalent resistor, an equivalent capacitor, and an equivalent inductor.

[0008] In a possible implementation manner, the electrode structure in the first patterned electrode forms the equivalent resistance, the equivalent capacitance and the equivalent inductance.

[0009] In a possible implementation, the passive filter further includes a second dielectric layer and a patterned dielectric, the second dielectric layer being arranged on a surface of the single crystal thin film substrate facing away from the first dielectric layer, and the patterned dielectric being arranged in the second dielectric layer; the first patterned electrode being arranged on a surface of the second dielectric layer facing away from the single crystal thin film substrate; the equivalent resistance, the equivalent capacitance and the equivalent inductance are formed in the first patterned electrode and the patterned dielectric.

[0010] In a possible implementation, the passive filter further includes a metal electrode, which is disposed inside the second dielectric layer or on a surface of the second dielectric layer facing away from the single crystal thin film substrate, and the equivalent resistance, the equivalent capacitance and the equivalent inductance are formed in the first patterned electrode, the patterned dielectric and the metal electrode.

[0011] In a possible implementation manner, the loss tangent value of the single crystal thin film substrate is less than 0.001;

[0012] In a possible implementation manner, the electron mobility of the single crystal thin film substrate is greater than 5000 cm 2 / (V·s).

[0013] In a possible implementation manner, the support substrate and the first dielectric layer are made of silicon-based materials or carbon-based materials;

[0014] In a possible implementation manner, the material of the single crystal thin film substrate is gallium arsenide or indium phosphide;

[0015] In a possible implementation manner, the first patterned electrode and the metal electrode are alloys formed by two or more of gold, copper, aluminum and silver.

[0016] In a possible implementation, the first patterned electrode includes an input port, an output port and an equivalent connection circuit, the equivalent connection circuit is used to connect the input port and the output port, the equivalent resistance, the equivalent capacitance and the equivalent inductance form the equivalent connection circuit, and the equivalent connection circuit is a resonant circuit.

[0017] The present invention further provides a hybrid filter, characterized in that it comprises the passive filter described in any one of the above embodiments and at least one acoustic wave resonator, wherein the passive filter is electrically connected to the acoustic wave resonator.

[0018] In a possible implementation manner, the passive filter and the acoustic wave resonator share the heterogeneous substrate assembly and the second dielectric layer.

[0019] Based on the above technical solution, the present invention has at least the following beneficial effects:

[0020] 1. The present invention provides a passive filter having a heterogeneous substrate assembly, a first patterned electrode and an equivalent circuit, wherein the heterogeneous substrate assembly includes a supporting substrate, a first dielectric layer and a single crystal thin film substrate. By providing a single crystal thin film substrate with a low loss factor and high electron mobility, it helps to reduce the RF loss of the substrate, improve the quality factor of the equivalent circuit, and thus reduce the insertion loss of the passive filter.

[0021] 2. The present invention also provides a hybrid filter that can integrate a passive filter with an acoustic wave resonator, and introduce a transmission zero by using the admittance response of the acoustic wave resonator, thereby improving the band edge steepness and out-of-band suppression level of the passband response, thereby obtaining a high-frequency, large-bandwidth filter device, and the hybrid filter also has low loss and excellent heat dissipation performance; the passive filter and the acoustic wave resonator share the same substrate, which is beneficial to improving the reliability and integration of the device and reducing the cost of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solution of the present invention, the following is a brief introduction to the drawings required for the prior art or embodiment description. Obviously, the drawings described below are only some embodiments of the present invention, and those skilled in the art can obtain other drawings based on these drawings without creative work.

[0023] Figure 1 : A cross-sectional view of a heterogeneous substrate assembly provided in an embodiment of the present application;

[0024] Figure 2 : A cross-sectional view of a passive filter provided in an embodiment of the present application;

[0025] Figure 3 : A cross-sectional view of a hybrid filter provided in an embodiment of the present application;

[0026] Figure 4 : Schematic diagram of an equivalent circuit of a passive filter provided in Example 1 of the present application;

[0027] Figure 5 : Schematic diagram of an equivalent circuit of a hybrid filter provided in Example 2 of the present application;

[0028] Figure 6 : Schematic diagram of an equivalent circuit of a hybrid filter provided in Example 3 of the present application;

[0029] Figure 7 : Response curves of the filter scattering parameter S21 provided in Example 1 and Comparative Example 1 of the present application;

[0030] Figure 8 : Response curve of the filter scattering parameter S21 provided in Examples 1 and 2 of the present application;

[0031] Fig. 9 : Response curve of the filter scattering parameter S21 provided in Examples 1 and 3 of the present application;

[0032] Reference numerals:

[0033] 10-heterogeneous substrate assembly, 11-support substrate, 12-first dielectric layer, 13-single crystal thin film substrate, 20-first patterned electrode, 31-equivalent resistance, 32-equivalent capacitance, 33-equivalent inductance, 40-second dielectric layer, 50-patterned dielectric, 60-surface layer. DETAILED DESCRIPTION

[0034] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making creative work are within the scope of protection of the present invention.

[0035] For the following defined terms, these definitions shall apply unless a different definition is given elsewhere in the claims or specification. All numerical values, whether or not explicitly indicated, are defined herein as modified by the term "about". The term "about" generally refers to a numerical range that is considered by those skilled in the art to be equivalent to the stated values ​​to produce substantially the same properties, functions, results, etc. A numerical range indicated by a lower value and a higher value is defined to cover all numerical values ​​included in this numerical range and all subranges included in this numerical range.

[0036] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including", "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, apparatus, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0037] The term "layer" as used in this application refers to a portion of a material including an area having a certain thickness. A layer may extend over the entire underlying or superstructure, or may extend over a localized area of ​​the underlying or superstructure. In addition, a layer may be an area of ​​a homogeneous or inhomogeneous continuous structure, the thickness of which is less than the thickness of the continuous structure. For example, a layer may be located between the top and bottom surfaces of a continuous structure or between any pair of horizontal planes therebetween. A layer may extend horizontally, vertically and / or along a tapered surface. A layer may include multiple layers. For example, a dielectric layer may include one or more dielectric sublayers, and may have the same or different materials.

[0038] The following is combined with Figure 1-9 The embodiments of the present invention are described, and the accompanying drawings do not limit the disclosure described in the claims in any way.

[0039] The embodiment of the present invention provides a passive filter, the passive filter comprising: a heterogeneous substrate component 10, referring to Figure 1 , including a supporting substrate 11, a first dielectric layer 12 and a single crystal thin film substrate 13; the first dielectric layer 12 is arranged on one side surface of the supporting substrate 11; the single crystal thin film substrate 13 is arranged on one side surface of the first dielectric layer 12 away from the supporting substrate 11; the first patterned electrode 20, the first patterned electrode 20 is arranged on the side of the single crystal thin film substrate 13 away from the first dielectric layer 12, and the first patterned electrode 20 and the heterogeneous substrate assembly 10 form at least a partial circuit structure of the equivalent circuit. The use of the heterogeneous substrate assembly 10, the first patterned electrode 20 and the equivalent circuit integrated passive filter is helpful to reduce the radio frequency loss of the substrate, improve the quality factor of the equivalent circuit, and then reduce the insertion loss of the passive filter, which is conducive to improving the reliability and integration of the device and reducing the device cost.

[0040] Specifically, the passive filter includes a heterogeneous substrate component 10 and a first patterned electrode 20. The heterogeneous substrate component 10 includes at least three layers of heterogeneous structures: a supporting substrate 11, a first dielectric layer 12, and a single crystal thin film substrate 13. The supporting substrate 11 is arranged at the bottom layer of the heterogeneous substrate component 10; the first dielectric layer 12 is arranged on the supporting substrate 11, that is, the first dielectric layer 12 is arranged on one side surface of the supporting substrate 11; the single crystal thin film substrate 13 is arranged on the first dielectric layer 12, that is, the single crystal thin film substrate 13 is arranged on the side surface of the first dielectric layer 12 away from the supporting substrate 11; the first patterned electrode 20 is arranged above the single crystal thin film substrate 13, that is, the first patterned electrode 20 is arranged on the side of the single crystal thin film substrate 13 away from the first dielectric layer 12. The heterogeneous substrate component 10 can form at least a partial circuit structure in an equivalent circuit with the first patterned electrode 20 to realize the device function of the passive filter.

[0041] In this way, a multilayer heterostructure including at least a supporting substrate 11, a first dielectric layer 12 and a single crystal thin film substrate 13, plus a first patterned electrode 20, can form at least a partial circuit structure in an equivalent circuit, providing a structural and electrical basis for realizing the device function of a passive filter.

[0042] In some embodiments, the material of the single crystal thin film substrate 13 is gallium arsenide or indium phosphide, which has low loss and high electron mobility, so that the single crystal thin film substrate has good radio frequency performance and can effectively avoid radio frequency loss caused by parasitic effects. Preferably, the single crystal thin film substrate 13 is a gallium arsenide single crystal thin film, which has extremely low dielectric loss and helps to improve the performance of the passive filter; and the gallium arsenide single crystal thin film can be reused to reduce the preparation cost.

[0043] In some embodiments, the loss tangent value of the single crystal thin film substrate 13 is less than 0.001, and the single crystal thin film substrate 13 has a low loss factor and small energy loss under the action of the electromagnetic field, which is beneficial to reducing the insertion loss of the passive filter, improving the quality factor, and enhancing the overall efficiency of the passive filter.

[0044] In some embodiments, the electron mobility of the single crystal thin film substrate 13 is greater than 5000 cm 2 / (V·s), the single crystal thin film substrate 13 has high electron mobility, and the electrons can respond to signal changes more quickly, so that the passive filter can operate in a wider frequency range, which is beneficial to maintaining low insertion loss and high isolation, and can reduce the device resistance and improve its overall efficiency.

[0045] In some embodiments, the material of the support substrate 11 and the first dielectric layer 12 may be a silicon-based material or a carbon-based material, including but not limited to a combination of one or more of silicon, silicon carbide, silicon oxide, and silicon nitride. In this way, the electrical system can be integrated on the support substrate 11 and the first dielectric layer 12 by utilizing the compatibility of semiconductor processing technology, silicon-based integration technology, and complementary metal oxide semiconductor (CMOS) technology. Preferably, the material of the support substrate 11 and the first dielectric layer 12 is a silicon-based material. Compared with gallium arsenide materials, silicon-based materials have higher thermal conductivity. When silicon-based materials are used as the support substrate, the heat dissipation performance of the passive filter can be enhanced, thereby improving the reliability of the device.

[0046] In some embodiments, the equivalent circuit includes an equivalent resistor 31 , an equivalent capacitor 32 , and an equivalent inductor 33 .

[0047] Specifically, the equivalent circuit of the passive filter includes electrical components such as an equivalent resistor 31, an equivalent capacitor 32, and an equivalent inductor 33. In this way, equivalent electrical components with certain resistance values, capacitance values, and inductance values ​​can jointly provide an equivalent circuit for the passive filter to achieve an electrical basis.

[0048] In some embodiments, the electrode structure in the first patterned electrode 20 forms an equivalent resistor 31 , an equivalent capacitor 32 , and an equivalent inductor 33 .

[0049] Specifically, the first patterned electrode 20 is arranged on the single crystal thin film substrate 13, that is, the first patterned electrode 20 is arranged on the side surface of the single crystal thin film substrate 13 away from the first dielectric layer 12, and the electrode structure of the first patterned electrode 20 is used to form electrical elements such as equivalent resistance 31, equivalent capacitance 32 and equivalent inductance 33.

[0050] In this way, by designing a first patterned electrode 20 having resistance, capacitance and inductance characteristics on the heterogeneous substrate assembly 10, electrical elements such as equivalent resistance 31, equivalent capacitance 32 and equivalent inductance 33 can be directly obtained, thereby forming an equivalent circuit, which facilitates the performance regulation of the passive filter.

[0051] In some embodiments, reference Figure 2 The passive filter also includes a second dielectric layer 40 and a patterned dielectric 50. The second dielectric layer 40 is arranged on a side surface of the single crystal thin film substrate 13 away from the first dielectric layer 12, and the patterned dielectric 50 is arranged in the second dielectric layer 40; the first patterned electrode 20 is arranged on a side surface of the second dielectric layer 40 away from the single crystal thin film substrate 13; the equivalent resistance 31, the equivalent capacitance 32 and the equivalent inductance 33 are formed in the first patterned electrode 20 and the patterned dielectric 50.

[0052] Specifically, the second dielectric layer 40 is arranged on the single crystal thin film substrate 13, that is, the second dielectric layer 40 is arranged on the side surface of the single crystal thin film substrate 13 away from the first dielectric layer 12, and a patterned dielectric 50 is arranged in the second dielectric layer 40; the first patterned electrode 20 is arranged on the second dielectric layer 40, that is, the first patterned electrode 20 is arranged on the side surface of the second dielectric layer 40 away from the single crystal thin film substrate 13; and electrical elements such as equivalent resistance 31, equivalent capacitance 32 and equivalent inductance 33 are formed in the first patterned electrode 20 and the patterned dielectric 50, which can realize the connection and conduction of the resonant circuit.

[0053] Specifically, the second dielectric layer 40 may be a combination of a single layer or multiple layers of materials, and the material of the second dielectric layer includes a combination of one or more materials such as silicon oxide, silicon nitride, and silicon carbide. Preferably, the second dielectric layer 40 is a combination of multiple layers of materials, and patterning one of the materials can form a patterned dielectric 50 inside the second dielectric layer 40, which is beneficial to adjusting the capacitance characteristics of the passive filter. Specifically, the material of the first dielectric layer 12 and the material of the second dielectric layer 40 may be the same or different.

[0054] In this way, an equivalent resistor 31, an equivalent capacitor 32 and an equivalent inductor 33 are designed in the first patterned electrode 20 and the patterned medium 50 to provide resistance values, capacitance values ​​and inductance values ​​for the passive filter to regulate its electrical performance, thereby being able to form more diverse electrical components, such as an equivalent parallel plate capacitor, etc.; and being able to effectively prevent short circuits, reduce parasitic effects between various components such as capacitors and inductors and interconnections, and adjust the values ​​of electrical components, thereby enhancing the application diversity of passive filters.

[0055] Preferably, the first patterned electrode 20 and the patterned medium 50 together form electrical elements such as an equivalent resistor 31 , an equivalent capacitor 32 , and an equivalent inductor 33 .

[0056] In some embodiments, the equivalent capacitor 32 may be a planar capacitor, including an interdigital capacitor, a flat plate capacitor, and the like.

[0057] In some embodiments, the equivalent capacitor 32 can be one of three-dimensional capacitors including but not limited to metal-insulator-metal (MIM) capacitors, metal-oxide-metal (MOM) capacitors, and multi-layer vertical interdigitated (VIC) capacitors, and the capacitance value can be adjusted by the capacitor area, the type and thickness of the capacitor dielectric layer, etc.

[0058] Specifically, when the equivalent capacitor 32 is a three-dimensional capacitor, the material of the patterned medium 50 may include, but is not limited to, silicon nitride, silicon oxide, silicon carbide, etc., and materials with low relative dielectric constant and low loss factor can effectively reduce parasitic effects. The patterned medium 50 can be formed by at least evaporation, thermal oxidation, magnetron sputtering, and electroplating.

[0059] In some embodiments, the equivalent inductor 33 may be a planar inductor, including but not limited to a meander line inductor, a polygonal spiral inductor, etc., and a higher quality factor may be achieved by adjusting the metal wire electrode width, the inner radius of the inductor, etc. of the equivalent inductor 33. It is understandable that in other embodiments, the equivalent inductor 33 may also be a three-dimensional inductor.

[0060] In some embodiments, the passive filter further includes a metal electrode, which is disposed inside the second dielectric layer 40 or on a side surface of the second dielectric layer 40 away from the single crystal thin film substrate 13, and an equivalent resistor 31, an equivalent capacitor 32, and an equivalent inductor 33 are formed in the first patterned electrode 20, the patterned dielectric 50, and the metal electrode. In this way, the metal electrode can interconnect components such as the equivalent resistor 31, the equivalent capacitor 32, and the equivalent inductor 33 to form an equivalent connection circuit; and the metal electrode can act as a current carrier in each component to reduce energy loss in the circuit.

[0061] Specifically, the passive filter further includes a through hole, which is disposed in the second dielectric layer 40 and is used to connect the metal electrode and the first patterned electrode 20 , thereby strengthening the connection and transmission of electrical signals between the layers.

[0062] In some embodiments, the first patterned electrode 20 and the metal electrode are alloys formed by two or more of gold, copper, aluminum and silver.

[0063] In some embodiments, the first patterned electrode 20 includes an input port, an output port and an equivalent connection circuit, the equivalent connection circuit is used to connect the input port and the output port, the input port is used to receive an input signal, the equivalent connection circuit is used to filter signals within a target frequency range and attenuate signals outside the target frequency range, and the output port is used to output the target frequency signal processed by the equivalent connection circuit.

[0064] Specifically, the equivalent resistor 31, the equivalent capacitor 32 and the equivalent inductor 33 form an equivalent connection circuit, which is a resonant circuit. In this way, the filtering response of the passive filter in different target frequency bands can be achieved by adjusting the parameters of the electrical components of the equivalent connection circuit.

[0065] The embodiment of the present invention further provides a hybrid filter, referring to Figure 3 , comprising the passive filter of any one of the above embodiments and at least one acoustic wave resonator, the passive filter being electrically connected to the acoustic wave resonator. In this way, by introducing a transmission zero point using the admittance response of the acoustic resonator, the band edge steepness and out-of-band suppression level of the passband response can be improved, thereby obtaining a high-frequency, large-bandwidth hybrid filter device, and the hybrid filter device has low loss, steep band edge, high out-of-band suppression and excellent heat dissipation performance.

[0066] Specifically, the acoustic resonator is arranged in the equivalent circuit of the passive filter. It can be understood that the acoustic resonator can be arranged in the series branch of the passive filter equivalent circuit; the acoustic resonator can also be arranged in the parallel branch of the passive filter equivalent circuit; or, at least one acoustic resonator can be arranged in both the series branch and the parallel branch of the passive filter equivalent circuit.

[0067] Specifically, the acoustic resonator includes but is not limited to a surface acoustic wave resonator, a bulk acoustic wave resonator, a Lamb wave resonator, etc. The acoustic resonator can be integrated with the passive filter at least by a bonding method, and the bonding method includes but is not limited to flip-chip bonding, metal wire bonding, metal through-hole connection, etc., which can realize the electrical connection between the passive filter and the acoustic resonator.

[0068] In some embodiments, the passive filter and the acoustic wave resonator share the heterogeneous substrate assembly 10 and the second dielectric layer 40. The passive filter region and the acoustic wave resonator region are set in the second dielectric layer 40, and the passive filter and the acoustic wave resonator are connected by metal leads to realize the integration of the hybrid filter on the same substrate.

[0069] In some embodiments, the hybrid filter further includes a surface layer 60 . The surface layer 60 is disposed on a side of the second dielectric layer 40 away from the single crystal thin film substrate. The first patterned electrode 20 is disposed on the surface layer 60 .

[0070] Specifically, the surface layer 60 can be a single crystal film with piezoelectric effect, and the acoustic resonator can be directly integrated on the piezoelectric single crystal film, that is, the integration of the electrical passive filter and the acoustic resonator can be realized simultaneously in the same structure. In this way, the passive filter and the acoustic resonator can be directly connected through electrodes, which is conducive to simplifying the device structure, reducing parasitic interference, and improving the reliability and integration of the device.

[0071] Specifically, the material of the piezoelectric single crystal thin film includes, but is not limited to, lithium niobate, lithium tantalate, aluminum nitride, potassium niobate, zinc oxide, and the like.

[0072] In some embodiments, the surface layer 60 includes a first surface layer and a second surface layer, the first surface layer is a gallium arsenide single crystal film, which is arranged in the passive filter area; the second surface layer is a single crystal film with piezoelectric effect, which is arranged in the acoustic resonator area, wherein the passive filter and the acoustic resonator are electrically connected through metal leads.

[0073] In some embodiments, the second surface layer may be a patterned piezoelectric single crystal film, and the material of the first surface layer includes but is not limited to a combination of one or more materials such as silicon oxide, silicon nitride, and silicon carbide. Thus, by patterning the second surface layer, the performance of the acoustic resonator can be adjusted.

[0074] Example 1

[0075] This embodiment provides a passive filter, including a heterogeneous substrate assembly 10 and a resonant circuit, wherein the heterogeneous substrate assembly 10 includes a supporting substrate 11, a first dielectric layer 12 and a single crystal thin film substrate 13, wherein the single crystal thin film substrate 13 is gallium arsenide, and the supporting substrate 11 and the first dielectric layer 12 are silicon-based materials; Figure 4 The resonant circuit includes an input port Z0, a first series branch, a first parallel branch, a second series branch, a second parallel branch, a third series branch, a third parallel branch and an output port Z1, wherein the first series circuit includes a first series capacitor C S1 and the first series inductor L S1 The second series circuit includes a second series capacitor C S2 and the second series inductor L S2, the third series circuit includes a third series capacitor C S3 and the third series inductor L S3 , the first parallel branch includes a first parallel capacitor C P1 and the first parallel inductor L P1 The second parallel branch includes a second parallel capacitor C P2 and the second parallel inductor L P2 , the third parallel branch includes a third parallel capacitor C P3 and the third parallel inductor L P3 , the input port Z0 is connected to the first series circuit, the third series circuit is connected to the output port Z1, the resistance of the input port Z0 and the output port Z1 are both 50 ohms; the parallel circuits are respectively placed at the output node positions of the first series circuit, the second series circuit and the third series circuit. The electrical parameters of each branch are shown in Table 1.

[0076] Example 2

[0077] This embodiment provides a hybrid filter, which connects the passive filter in Embodiment 1 in parallel with an acoustic resonator R1, wherein the acoustic resonator R1 is a surface acoustic wave resonator based on a lithium niobate-silicon oxide-silicon substrate. The equivalent circuit of the hybrid integration is as follows: Figure 5 As shown, the difference from the equivalent circuit in Example 1 is that in this embodiment, an acoustic resonator R1 is connected in parallel between the input port Z0 and the first series circuit, and the rest is the same as Example 1. The equivalent connection circuit parameters of the parallel acoustic resonator R1 are shown in Table 2.

[0078] Example 3

[0079] This embodiment provides a hybrid filter, wherein the passive filter in Embodiment 1 is connected in parallel with an acoustic resonator R2 and in series with another acoustic resonator R3. Both acoustic resonators are surface acoustic wave resonators based on lithium niobate-silicon oxide-silicon substrate. The equivalent circuit of the hybrid integration is as follows: Figure 6 As shown, the difference from the equivalent circuit in Example 1 is that in this embodiment, an acoustic resonator R2 is connected in parallel between the input port Z0 and the first series circuit, and another acoustic resonator R3 is connected in series between the third parallel circuit and the output port Z1, and the rest is the same as Example 1. The equivalent connection circuit parameters of the parallel acoustic resonator R2 are shown in Table 3, and the equivalent connection circuit parameters of the series acoustic resonator R3 are shown in Table 4.

[0080] Comparative Example 1

[0081] This comparative example provides a passive filter, which is different from Example 1 in that this comparative example uses silicon as a substrate to integrate the passive filter, and the resonant circuit structure is the same as that of Example 1, which will not be described here. The electrical parameters of each branch are shown in Table 5.

[0082] Table 1 Resonance circuit parameters of Example 1

[0083]

[0084]

[0085] Table 2 Equivalent circuit parameters of parallel acoustic resonator in Example 2

[0086]

[0087] Table 3 Equivalent circuit parameters of the parallel acoustic resonator in Example 3

[0088]

[0089] Table 4 Equivalent circuit parameters of the series acoustic resonator in Example 3

[0090]

[0091]

[0092] Table 5 Resonant circuit parameters of comparative example 1

[0093]

[0094] Referring to the electrical parameters in Table 1 and Table 5, combined with Example 1 and Comparative Example 1, it can be seen that the difference in intrinsic loss between Example 1 and Comparative Example 1 is represented by the difference in the resistance value of the inductor. The higher the resistance value of the inductor, the greater the intrinsic RF loss of the device. The inductor resistance value of each branch in Comparative Example 1 is greater than the inductor resistance value of each corresponding branch in Example 1, proving that the passive filter provided in Example 1 has smaller device loss and higher quality factor.

[0095] refer to Figure 7 , M1 is the response curve of the passive filter in Example 1, M4 is the response curve of the passive filter in Comparative Example 1, the center frequency of the passive filter in Example 1 is about 6.81GHz, the minimum loss in the band is 2.81dB, and the 3dB relative bandwidth is 15.9%, achieving high frequency, low loss, and wide bandwidth response; while the center frequency of the passive filter in Comparative Example 1 is about 6.83GHz, the minimum loss in the band is 7.1dB, and the 3dB relative bandwidth is 13.3%. Obviously, when the heterogeneous substrate component 10 with smaller RF loss is used in Example 1, the insertion loss of the passive filter is significantly reduced, so that the 3dB relative bandwidth is increased, the filtering performance is greatly improved, and it is beneficial to improve the quality factor of the electrical component.

[0096] Combined with Example 1 and Example 2, refer to Figure 8It can be seen from Table 1 and Table 2 that in Example 2, when the parallel acoustic parallel resonator is introduced into the resonant circuit and its parameters are adjusted appropriately, the transmission zero point A can be effectively introduced on the left side of the target passband, so that the steepness of the band edge at the low-frequency end is significantly improved, and the out-of-band suppression on the left side of the passband is optimized from 30dB to 45dB, without affecting the insertion loss within the passband. Figure 8 M2 is the response curve of the hybrid filter in Example 2. The center frequency of the hybrid filter in Example 2 is about 6.82 GHz, the minimum loss in the band is 2.83 dB, and the 3dB relative bandwidth is 15.4%, which proves that after the integrated parallel acoustic resonator, the hybrid filter still maintains a high-frequency, low-loss, and wide-bandwidth response.

[0097] Combined with Example 1 and Example 3, refer to Fig. 9 It can be seen from Table 1, Table 3 and Table 4 that when Example 3 introduces a parallel acoustic resonator and a series acoustic resonator in the resonant circuit and adjusts their parameters appropriately, a transmission zero point A1 can be introduced on the left side of the target passband, and a transmission zero point A2 can be introduced on the right side of the target passband, so that the band edge steepness at the low-frequency end and the band edge steepness at the high-frequency end are significantly improved, and the out-of-band suppression on the left side of the passband is optimized from 20dB to 45dB, and the out-of-band suppression on the right side of the passband is also optimized from 18dB to 35dB, and does not affect the insertion loss within the passband. Fig. 9 M3 is the response curve of the hybrid filter in Example 3. The center frequency of the hybrid filter in Example 3 is about 6.80 GHz, the minimum loss in the band is 2.71 dB, and the 3dB relative bandwidth is 14.93%, which proves that after integrating series and parallel acoustic resonators, the hybrid filter still maintains high frequency, low loss and large bandwidth response.

[0098] It can be seen that when there are multiple parallel resonators and / or multiple series resonators, by setting their parameters reasonably, multiple transmission zeros can be introduced at the low-frequency end on the left side of the passband and / or the high-frequency end on the right side of the passband, making the band edge steeper. In addition, by introducing transmission zeros using the admittance response of the acoustic resonator, the band edge steepness and out-of-band suppression level of the passband response can be improved, thereby obtaining a filter device with high frequency, large bandwidth, low loss, steep band edge and high out-of-band suppression.

[0099] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0100] It should be noted that all the features recorded in the present invention (including technical features recorded in different embodiments) can be combined arbitrarily under reasonable circumstances, and new technical solutions formed by the combination are all within the protection scope of the present invention.

[0101] What is described above are only some embodiments of the present invention and are not intended to limit the present invention. Those skilled in the art should understand that the present invention may be subject to various changes and improvements, and any modifications, equivalent substitutions and improvements made in accordance with the present invention shall fall within the scope of protection required by the present invention.

Claims

1. A passive filter, characterized in that: The passive filter comprises: A heterogeneous substrate assembly comprises a supporting substrate, a first dielectric layer and a single crystal thin film substrate; the first dielectric layer is arranged on a side surface of the supporting substrate; the single crystal thin film substrate is arranged on a side surface of the first dielectric layer away from the supporting substrate; A first patterned electrode is disposed on a side of the single crystal thin film substrate away from the first dielectric layer, and the first patterned electrode and the heterogeneous substrate assembly at least form a partial circuit structure of an equivalent circuit.

2. The passive filter according to claim 1, characterized in that: The equivalent circuit includes an equivalent resistor, an equivalent capacitor and an equivalent inductor.

3. The passive filter according to claim 2, characterized in that: The electrode structure in the first patterned electrode forms the equivalent resistance, the equivalent capacitance and the equivalent inductance.

4. The passive filter according to claim 2, characterized in that: The passive filter also includes a second dielectric layer and a patterned dielectric, wherein the second dielectric layer is arranged on a surface of the single crystal thin film substrate facing away from the first dielectric layer, and the patterned dielectric is arranged in the second dielectric layer; the first patterned electrode is arranged on a surface of the second dielectric layer facing away from the single crystal thin film substrate; the equivalent resistance, the equivalent capacitance and the equivalent inductance are formed in the first patterned electrode and the patterned dielectric.

5. The passive filter according to claim 4, characterized in that: The passive filter also includes a metal electrode, which is arranged inside the second dielectric layer or on a surface of the second dielectric layer that is away from the single crystal thin film substrate. The equivalent resistance, the equivalent capacitance and the equivalent inductance are formed in the first patterned electrode, the patterned dielectric and the metal electrode.

6. The passive filter according to any one of claims 1 to 5, characterized in that: The passive filter satisfies at least one of the following characteristics: The loss tangent value of the single crystal thin film substrate is less than 0.001; The electron mobility of the single crystal thin film substrate is greater than 5000 cm 2 / (V·s).

7. The passive filter according to any one of claims 1 to 5, characterized in that: The passive filter satisfies at least one of the following characteristics: The support substrate and the first dielectric layer are made of silicon-based materials or carbon-based materials; The material of the single crystal thin film substrate is gallium arsenide or indium phosphide; The first patterned electrode and the metal electrode are alloys formed by two or more of gold, copper, aluminum and silver.

8. The passive filter according to any one of claims 1 to 5, characterized in that: The first patterned electrode includes an input port, an output port and an equivalent connection circuit, wherein the equivalent connection circuit is used to connect the input port and the output port, the equivalent resistance, the equivalent capacitance and the equivalent inductance form the equivalent connection circuit, and the equivalent connection circuit is a resonant circuit.

9. A hybrid filter, characterized in that: The invention comprises the passive filter according to any one of claims 1 to 8 and at least one acoustic wave resonator, wherein the passive filter is electrically connected to the acoustic wave resonator.

10. The hybrid filter according to claim 9, characterized in that The passive filter and the acoustic wave resonator share the heterogeneous substrate assembly and the second dielectric layer.

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