Structure and device of silicon-based cantilever MEMS piezoelectric microphone

Abstract

The present application relates to the structure and device of a silicon-based cantilever beam MEMS piezoelectric microphone, and in particular to the field of microphone devices. The structure of the silicon-based cantilever beam MEMS piezoelectric microphone provided by the present application includes: a substrate, a first electrode layer, a piezoelectric material layer, and a second electrode layer. Since the first electrode layer, the piezoelectric material layer, and the second electrode layer are all in the shape of a "T"-shaped structure, and the short end of the first electrode layer of the "T"-shaped structure is connected to the edge of the opening position of an open cavity structure, the first electrode layer, the piezoelectric material layer, and the second electrode layer form a cantilever beam structure. The cantilever beam structure can vibrate under the action of sound vibration, thereby causing the charge on the piezoelectric material layer to transfer, thereby causing the amount of charge on the first electrode layer and the second electrode layer to change, that is, the output of the microphone structure changes, and a more accurate sound signal can be obtained by detecting the output electrical signal.

Description

Technical Field

[0001] The present application relates to the field of microphone devices, and in particular to a structure and device of a silicon-based cantilever beam MEMS piezoelectric microphone. Background Art

[0002] Microphone is an energy conversion device that converts sound signals into electrical signals. It is also called microphone or micro-phone. It has been widely used in various electronic fields, military fields, medical fields, etc. In addition, sensitivity and low resonant frequency will become necessary conditions.

[0003] MEMS microphones are now widely used in consumer electronics. With the advancement of technology, piezoelectric silicon microphones have gradually begun to develop. However, compared with capacitor microphones, the biggest disadvantage of piezoelectric microphones that affects their popularization is that the sensitivity of piezoelectric microphones is too low due to the higher resonant frequency of the sensor. In other words, the ability of the piezoelectric film to sense audio signals is far lower than that of the diaphragm in the capacitor microphone.

[0004] The operating frequency of a microphone is generally 20-20kHz. In order to improve the sensitivity of a piezoelectric microphone, most manufacturers use slots on the piezoelectric film. However, this slot design causes serious leakage of low-frequency signals and even intermediate-frequency signals, resulting in low sensitivity of the microphone in the prior art. Summary of the invention

[0005] The purpose of the present invention is to provide a structure and device of a silicon-based cantilever beam MEMS piezoelectric microphone in view of the above-mentioned deficiencies in the prior art, so as to solve the problem that in order to reduce the resonant frequency of the sensor and further improve the sensitivity of the piezoelectric microphone in the prior art, most manufacturers use slots on the piezoelectric film, but the design of the slots makes the leakage of low-frequency signals and even intermediate-frequency signals very serious, making the microphone sensitivity in the prior art low. At the same time, the microphone frequency response is wide and flat, and the key dimensions of the microphone structure are optimized, so that the maximum deviation in the passband can be achieved within 3dB, which helps the microphone system design to achieve natural and clear sound.

[0006] To achieve the above purpose, the technical solution adopted by the embodiment of the present invention is as follows:

[0007] In a first aspect, the present application provides a structure of a silicon-based cantilever beam MEMS piezoelectric microphone, the structure comprising: a substrate, a first electrode layer, a piezoelectric material layer, and a second electrode layer; the substrate is an open cavity structure, the first electrode layer, the piezoelectric material layer, and the second electrode layer are all in the shape of a "T"-shaped structure, and the short end of the first electrode layer of the "T"-shaped structure is connected to the edge of the opening position of the open cavity structure, the piezoelectric material layer is arranged on a side of the first electrode layer away from the substrate, the second electrode layer is arranged on a side of the piezoelectric material layer away from the first electrode layer, and the first electrode layer, the piezoelectric material layer, and the second electrode layer are all parallel to the horizontal plane, and the projections on the horizontal plane are the same.

[0008] Optionally, the structure further includes a third electrode layer, a second piezoelectric material layer and a fourth electrode layer, the third electrode layer is connected to the edge of the opening position of the open cavity structure, and the second piezoelectric material layer and the fourth electrode layer are sequentially arranged on the side of the fourth electrode layer away from the substrate.

[0009] Optionally, the structure further includes a fifth electrode layer and a third piezoelectric material layer, the third piezoelectric material layer is arranged on a side of the second electrode layer away from the piezoelectric material layer, and the third electrode layer is arranged on a side of the third piezoelectric material layer away from the second electrode layer.

[0010] Optionally, the structure further includes a support layer, and the support layer is arranged on a side of the substrate away from the first electrode layer.

[0011] Optionally, the structure further includes a silicon layer, and the silicon layer is arranged on a side of the first electrode layer close to the substrate.

[0012] Optionally, the structure further includes a silicon oxide portion and a device layer silicon portion, the silicon oxide portion is arranged at an opening position of the substrate and is consistent with the upper surface of the substrate, and the device layer silicon portion is placed on the silicon oxide and on a side away from the first electrode layer.

[0013] In a second aspect, the present application provides a device of a silicon-based cantilever beam MEMS piezoelectric microphone, comprising a digital-to-analog conversion device and the structure of any one of the silicon-based cantilever beam MEMS piezoelectric microphones of the first aspect, wherein the positive and negative electrodes of the digital-to-analog conversion device are electrically connected to the first electrode layer and the second electrode layer of the structure, respectively, for converting the charge signals output by the first electrode layer and the second electrode layer into digital signals.

[0014] The beneficial effects of the present invention are:

[0015] The structure of a silicon-based cantilever beam MEMS piezoelectric microphone provided by the present application includes: a substrate, a first electrode layer, a piezoelectric material layer, and a second electrode layer; the substrate is an open cavity structure, the first electrode layer, the piezoelectric material layer, and the second electrode layer are all in the shape of a "T"-shaped structure, and the short end of the first electrode layer of the "T"-shaped structure is connected to the edge of the opening position of the open cavity structure, the piezoelectric material layer is arranged on the side of the first electrode layer away from the substrate, and the second electrode layer is arranged on the side of the piezoelectric material layer away from the first electrode layer, and the first electrode layer, the piezoelectric material layer, and the second electrode layer are all parallel to the horizontal plane, and their projections on the horizontal plane are the same, because the first electrode layer, the piezoelectric material layer, and the second electrode layer are all in the shape of a "T"-shaped structure, and the short end of the first electrode layer of the "T"-shaped structure is connected to the edge of the opening position of the open cavity structure, the first electrode layer, the piezoelectric material layer, and the second electrode layer form a cantilever beam structure. The cantilever beam structure microphone vibrates under the action of sound signals. According to the piezoelectric effect of the piezoelectric material, the charge on the surface of the piezoelectric material layer on the microphone is transferred, thereby changing the amount of charge on the first electrode layer and the second electrode layer, that is, the output signal of the microphone structure changes. By detecting the output charge signal, an accurate sound signal can be obtained. In addition, due to the cantilever beam structure of the present application, the vibration amplitude of the cantilever beam structure is larger under the action of sound, which further reduces the resonant frequency, so that the microphone structure of the present application has higher low-frequency sensitivity and the output electrical signal related to the sound signal is more accurate and stable. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0017] Figure 1 A schematic structural diagram of a silicon-based cantilever beam MEMS piezoelectric microphone provided by one embodiment of the present invention;

[0018] Figure 2 A schematic structural diagram of another silicon-based cantilever beam MEMS piezoelectric microphone provided in one embodiment of the present invention;

[0019] Figure 3 A schematic structural diagram of another silicon-based cantilever beam MEMS piezoelectric microphone provided by an embodiment of the present invention;

[0020] Figure 4A schematic diagram showing the effect of a change in the length of a vibration beam of a cantilever beam piezoelectric microphone structure on the resonant frequency of the entire microphone structure provided by one embodiment of the present invention;

[0021] Figure 5 A schematic diagram showing the effect of a change in the side length of a vibration membrane of a cantilever beam piezoelectric microphone on the resonant frequency of the overall microphone structure provided by an embodiment of the present invention;

[0022] Figure 6 A schematic diagram of the sensitivity of a cantilever beam piezoelectric microphone provided by an embodiment of the present invention;

[0023] Figure 7 A schematic diagram of a frequency response curve of a cantilever beam piezoelectric microphone provided by an embodiment of the present invention;

[0024] Figure 8 A schematic structural diagram of another silicon-based cantilever beam MEMS piezoelectric microphone provided by an embodiment of the present invention;

[0025] Fig. 9 A schematic structural diagram of another silicon-based cantilever beam MEMS piezoelectric microphone provided by an embodiment of the present invention.

[0026] Icon: 10 - substrate; 11 - support layer; 20 - first electrode layer; 21 - silicon layer; 30 - piezoelectric material layer; 40 - second electrode layer; 50 - third electrode layer; 60 - second piezoelectric material layer; 70 - fourth electrode layer; 80 - third piezoelectric material layer; 90 - fifth electrode layer. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiment is one embodiment of the present invention, not all embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0028] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0030] In order to make the implementation process of the present invention clearer, it will be described in detail below with reference to the accompanying drawings.

[0031] Figure 1 A schematic diagram of the structure of a silicon-based cantilever beam MEMS piezoelectric microphone provided by one embodiment of the present invention; Figure 1 As shown, the present application provides a structure of a silicon-based cantilever beam MEMS piezoelectric microphone, the structure comprising: a substrate 10, a first electrode layer 20, a piezoelectric material layer 30 and a second electrode layer 40; the substrate 10 is an open cavity structure, the first electrode layer 20, the piezoelectric material layer 30 and the second electrode layer 40 are all in the shape of a "T"-shaped structure, and the short end of the first electrode layer 20 of the "T"-shaped structure is connected to the edge of the opening position of the open cavity structure, the piezoelectric material layer 30 is arranged on a side of the first electrode layer 20 away from the substrate 10, and the second electrode layer 40 is arranged on a side of the piezoelectric material layer 30 away from the first electrode layer 20, and the first electrode layer 20, the piezoelectric material layer 30 and the second electrode layer 40 are all parallel to the horizontal plane, and the projections on the horizontal plane are the same.

[0032] The shape and size of the substrate 10 are set according to actual needs, and are not specifically limited here. In practical applications, the shape of the substrate 10 is a rectangular parallelepiped structure, the interior of the rectangular parallelepiped is a cavity structure, and one side of the cavity structure of the rectangular parallelepiped is open. The size of the opening position is set according to actual needs. For the convenience of explanation, the size of the opening on the substrate 10 is equal to the size of the top surface of the substrate 10. The edge position of the opening position of the substrate 10 is sequentially provided with a first electrode layer 20, a piezoelectric material layer 30 and a second electrode layer 40, and the first electrode layer 20, the piezoelectric material layer 30 and the second electrode layer 40 are sequentially provided. The shapes of the material layer 30 and the second electrode layer 40 are exactly the same, both of which are "T"-shaped structures, that is, the cantilever beam structure composed of the first electrode layer 20, the piezoelectric material layer 30 and the second electrode layer 40 includes a long end and a short end, wherein the width of the long end position is greater than the width of the short end position, and the short end of the first electrode layer 20 is connected to the edge position of the opening position of the substrate 10, so that the first electrode layer 20 is parallel to the bottom surface of the substrate 10, and the piezoelectric material layer 30 is arranged on the upper surface of the first electrode layer 20, and the second electrode layer 40 is arranged on the upper surface of the piezoelectric material layer 30. Due to the inverse piezoelectric effect, the piezoelectric material layer 30 moves the charge in a directional manner under the action of pressure. Since the second electrode layer 40 is arranged on the upper surface of the piezoelectric material layer 30 and the first electrode layer 20 is arranged on the lower surface, when the piezoelectric material layer 30 vibrates or deforms under the action of pressure, the charge amount on the upper and lower surfaces of the piezoelectric material layer 30 changes, thereby changing the voltage detected by the first electrode layer 20 and the second electrode layer 40.

[0033] In practical applications, the microphone structure of the present application is used to collect sound signals. Since sound signals are generated by vibrations, the process of transmitting sound signals is also a process of transmitting vibrations. When the vibration signal corresponding to the sound signal acts on the cantilever beam, the cantilever beam also vibrates, thereby causing the piezoelectric material layer 30 to vibrate, thereby changing the voltage between the first electrode layer 20 and the second electrode layer 40, which is equivalent to converting the vibration information of the sound signal into a voltage signal. It should be noted that the vibration information of the sound signal has a corresponding relationship with the voltage signal. In practical applications, the cantilever beam structure can vibrate under the action of the vibration of the sound, thereby causing the piezoelectric material layer 30 to vibrate. The charge on the electrical material layer 30 is transferred, so that the amount of charge on the first electrode layer 20 and the second electrode layer 40 changes, that is, the output voltage of the microphone structure changes. By detecting the output voltage signal, an accurate sound signal can be obtained. In addition, due to the cantilever beam structure of the present application, the vibration amplitude of the cantilever beam structure under the action of sound is larger. Since the amplitude is negatively correlated with the vibration frequency, the resonant frequency is further reduced, so that the microphone structure of the present application has higher sensitivity, and the output voltage signal related to the sound signal is more accurate and stable. The size relationship between the long end and the short end of the cantilever beam is set according to actual needs and is not specifically limited here.

[0034] Generally, the larger the size ratio of the long end to the short end, the smaller the resonant frequency of the cantilever beam, making the acquired sound information clearer. According to the simulation results, in actual applications, the size ratio of the long end to the short end of the cantilever beam is controlled to achieve the control of the resonant frequency of the cantilever beam to 40kHz-60kHz. At this time, the microphone has a higher output in its working frequency band, the highest sensitivity and the flatness of the microphone receiving frequency is higher, further ensuring that the sound signal received by the microphone is not distorted, so that the stability and accuracy of the sound signal received and transmitted by the microphone are higher. The material of the first electrode layer 20 in this application can be at least one or more of molybdenum, titanium, gold, and copper. The piezoelectric material layer is a piezoelectric material. Piezoelectric materials refer to a large class of single crystal or polycrystalline solid materials with electric charges on their two end surfaces under pressure, and are important carriers for energy conversion and signal transmission. Piezoelectric materials themselves have good dynamic characteristics and rich vibration modes. The acoustic emission spectrum of various materials almost covers the entire frequency band. Piezoelectric materials can respond quickly to external forces with their excellent electromechanical coupling effect. The piezoelectric material in this patent can be aluminum nitride, which has the same or higher performance than other MEMS piezoelectric materials (such as zinc oxide and lead zirconate titanate), and its compatibility is better than any of the two materials. In addition, the piezoelectric material can also be lithium niobate, etc.

[0035] Figure 2A schematic diagram of the structure of another silicon-based cantilever beam MEMS piezoelectric microphone provided by an embodiment of the present invention; Figure 2 As shown, optionally, the structure also includes a third electrode layer 50, a second piezoelectric material layer 60 and a fourth electrode layer 70, the third electrode layer 50 is connected to the edge of the opening position of the open cavity structure, and the second piezoelectric material layer 60 and the fourth electrode layer 70 are sequentially arranged on the side of the fourth electrode layer 70 away from the substrate 10.

[0036] The third electrode layer 50, the second piezoelectric material layer 60 and the fourth electrode layer 70 form a second cantilever beam, which is connected to the edge of the opening position of the open cavity structure. The third electrode layer 50, the second piezoelectric material layer 60 and the fourth electrode layer 70 in the second cantilever beam are arranged away from the substrate 10 in sequence. The second cantilever beam is away from the narrow end and the wide end of the cantilever beam respectively, and the size is consistent, forming a square structure. The cantilever beams are all located on the cavity, and the edges are fixed on the substrate, respectively located on the corresponding two sides. The array design is adopted to improve the output response and sensitivity of the microphone. The two cantilever beam structures adopt a point-symmetrical design, which complements each other, so that the microphone structure has a better smooth response effect within the working frequency band.

[0037] Optionally, the microphone structure may further include a plurality of cantilever beams, which are periodically spaced apart, and an array design is adopted to enhance the output of the microphone, so that the accuracy and stability of the sound signal acquired by the microphone are higher.

[0038] Figure 3 A schematic diagram of the structure of another silicon-based cantilever beam MEMS piezoelectric microphone provided by an embodiment of the present invention; Figure 3 As shown, optionally, the structure further includes a fifth electrode layer 90 and a third piezoelectric material layer 80 , wherein the third piezoelectric material layer 80 is disposed on a side of the second electrode layer 40 away from the piezoelectric material layer 30 , and the third electrode layer is disposed on a side of the third piezoelectric material layer 80 away from the second electrode layer 40 .

[0039] The third piezoelectric material layer 80 is arranged on the upper part of the second electrode layer 40, and the fifth electrode layer 90 is arranged on the upper part of the third piezoelectric material layer 80. The piezoelectric material layer 30 and the third piezoelectric material layer 80 will both vibrate under the action of the sound signal, so that the thickness of the cantilever beam of the present application is thickened, and thus under the action of the same sound signal, the output electrical signal of the cantilever beam is higher, and the flatness within the passband is further improved, so that the accuracy of the sound information obtained by the present application is further improved, and the quality of the sound information obtained by the microphone structure of the present application is higher. At the same time, the increase in the thickness of the piezoelectric structure further improves the reliability of the microphone.

[0040] Figure 4A schematic diagram showing the effect of a change in the length of a vibration beam of a cantilever beam piezoelectric microphone structure on the resonant frequency of the entire microphone structure provided by the third embodiment of the present invention; Figure 5 A schematic diagram showing the effect of a change in the side length of a vibration membrane of a cantilever beam piezoelectric microphone on the resonant frequency of the overall microphone structure provided by the third embodiment of the present invention; Figure 6 A schematic diagram of the sensitivity of a cantilever beam piezoelectric microphone provided by the third embodiment of the present invention; Figure 7 A schematic diagram of a frequency response curve of a cantilever beam piezoelectric microphone provided in the third embodiment of the present invention; the device in this embodiment includes two cantilever beam structures, which are arranged in this way, by optimizing the key dimensions of the device, including the dimensions and thickness of the first electrode layer 20, the second electrode layer 40, the third electrode layer 50, the fourth electrode layer 70, the piezoelectric material layer 30 and the second piezoelectric material layer 60, so that the device of the present application can achieve functions that can only be achieved with a larger size under the condition of a smaller size, so that the final resonant frequency of the device of the present application can be reduced to the range of 5-350kHz, and it can be obtained that this structure can reach a lower frequency range, and has great potential in the design and preparation of low-frequency piezoelectric devices. The side length of the parametrically scanned cantilever beam structure, such as Figure 4 As shown, the horizontal axis represents the cross-sectional length of the beam, the vertical axis represents the resonant frequency of the structure, and the length of the beam is changed, including the first electrode layer 20, the first piezoelectric material layer 30, the second electrode layer 40, the third piezoelectric material layer 80 and the fifth electrode layer 90. According to the data schematic diagram, under the condition of a given width, the increase in the cantilever beam length will reduce the resonant frequency of the device, thereby affecting the sensitivity of the microphone structure; Figure 5 As shown in the figure, the horizontal axis represents the side length of the square section of the vibration membrane, and the vertical axis represents the resonant frequency of the piezoelectric microphone. By changing the side length of the square side of the entire microphone vibration membrane, it can be obtained that as the side length increases, the resonant frequency of the microphone gradually decreases, and the decrease rate changes from fast to slow. The frequency can be reduced to below 20kHz and reach 8kHz. From the simulation results, this cantilever beam structure has great potential in the application of very low frequency devices. At the same time, multi-physics field coupling simulation of the structure can also be obtained, such as Figure 6 As shown, the horizontal axis represents frequency, and the vertical axis represents the sensitivity of the structure, that is, the proportional relationship between the output voltage and the input sound pressure. This schematic diagram can show the change of microphone sensitivity with vibration frequency. It can be concluded that the sensitivity of the structure can reach 0.1mV / Pa, and the sensitivity can be further improved by further optimizing the key dimensions of the cantilever beam and combining material optimization. In addition, Figure 7 The frequency response curve of the microphone structure shown in the third embodiment of the present invention is shown, which represents the relationship between the output and input frequencies of the structure. It can be seen that within the frequency range of 20-20kHz, the unevenness of the structure is about 1.1dB, the maximum unevenness is well within 3dB, and the frequency response curve has a high flatness.

[0041] Figure 8 A schematic diagram of the structure of another silicon-based cantilever beam MEMS piezoelectric microphone provided by an embodiment of the present invention; Figure 8 As shown, optionally, the structure further includes a support layer 11 , and the support layer 11 is disposed on a side of the substrate 10 away from the first electrode layer 20 .

[0042] The support layer 11 is disposed on a side of the substrate 10 away from the first electrode layer 20. The support layer 11 is used to support the substrate 10 to prevent the piezoelectric material layer 30 from breaking. When the cantilever beam structure vibrates, the support layer 11 can play a protective role to prevent the structure from breaking when overloaded. Therefore, in practical applications, the support layer 11 at the bottom of the substrate 10 is generally prepared using a Si-Si bonding process.

[0043] Fig. 9 A schematic diagram of the structure of another silicon-based cantilever beam MEMS piezoelectric microphone provided by an embodiment of the present invention; Fig. 9 As shown, optionally, the structure further includes a silicon layer 21 , and the silicon layer 21 is disposed on a side of the first electrode layer 20 close to the substrate 10 .

[0044] The silicon layer 21 is used to support the first electrode layer 20, the piezoelectric material layer 30 and the second electrode layer 40 to increase the thickness of the cantilever beam, and further increase the resonant frequency of the device under the action of the sound signal of the same intensity, thereby reducing the deformation of the piezoelectric material layer 30 under the action of the sound signal of the same intensity, that is, the output voltage information of the piezoelectric material layer 30 also changes accordingly, thereby further improving the accuracy of the sound information obtained in the present application, and further improving the flatness within the frequency band of the microphone, thereby making the quality of the obtained sound information higher.

[0045] Optionally, the structure also includes a silicon oxide portion and a device layer silicon portion, the silicon oxide portion is arranged above the substrate 10, consistent with the upper surface of the substrate 10, and has the same opening position, and the device layer silicon portion is placed on the upper part of the silicon oxide and on the side of the first electrode layer away from the piezoelectric material layer.

[0046] The substrate layer structure adopts an SOI substrate, which can reduce the process steps and improve the reliability of the process preparation. The SOI bottom silicon and the SOI silicon oxide part are used as the support layer 11. At the same time, the bottom silicon and the silicon oxide part both adopt the opening structure shown in the cantilever beam substrate 10. The SOI top device layer silicon is used for the piezoelectric structure layer, which is placed on the side of the first electrode layer away from the piezoelectric material layer, consistent with the structural upper surface of the electrode layer and the piezoelectric layer. The presence of the SOI top device layer silicon increases the thickness of the entire cantilever beam, improves the reliability of the device, and relatively improves the resonant frequency of the device, thereby further improving the flatness of the microphone within the frequency band, thereby making the quality of the acquired sound information higher.

[0047] Optionally, the preparation method of the present application: prepare a silicon wafer, sputter electrode material / piezoelectric material / electrode material on the silicon wafer substrate in sequence, pattern the electrode material / piezoelectric material / electrode material from top to bottom, and complete the etching of the electrode pad, and finally perform back cavity etching to etch the substrate opening cavity.

[0048] The present application provides a device of a silicon-based cantilever beam MEMS piezoelectric microphone, which includes a digital-to-analog conversion device and any one of the above-mentioned silicon-based cantilever beam MEMS piezoelectric microphone structures, wherein the positive and negative electrodes of the digital-to-analog conversion device are electrically connected to the first electrode layer 20 and the second electrode layer 40 of the structure, respectively, and are used to convert the voltage signals output by the first electrode layer 20 and the second electrode layer 40 into digital signals.

[0049] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A structure of a silicon-based cantilever beam MEMS piezoelectric microphone, characterized in that: The structure includes: a substrate, a first electrode layer, a piezoelectric material layer, and a second electrode layer; the substrate is an open cavity structure, the first electrode layer, the piezoelectric material layer, and the second electrode layer are all in a "T"-shaped structure, and the short end of the first electrode layer of the "T"-shaped structure is connected to the edge of the opening position of the open cavity structure, the piezoelectric material layer is arranged on a side of the first electrode layer away from the substrate, the second electrode layer is arranged on a side of the piezoelectric material layer away from the first electrode layer, and the first electrode layer, the piezoelectric material layer, and the second electrode layer are all parallel to a horizontal plane, and the projections on the horizontal plane are the same, and the first electrode layer The layer, the piezoelectric material layer and the second electrode layer form a first cantilever beam; the structure also includes a third electrode layer, a second piezoelectric material layer and a fourth electrode layer, the third electrode layer is connected to the edge of the opening position of the open cavity structure, the second piezoelectric material layer and the fourth electrode layer are sequentially arranged on the side of the third electrode layer away from the substrate, and the third electrode layer, the second piezoelectric material layer and the fourth electrode layer form a second cantilever beam; the second cantilever beam and the first cantilever beam are respectively fixed on the corresponding two sides of the opening position, the narrow end and the wide end of the second cantilever beam and the first cantilever beam are respectively far away from each other and have the same shape and size, forming a square structure.

2. The structure of the silicon-based cantilever beam MEMS piezoelectric microphone according to claim 1, characterized in that: The structure further includes a support layer, which is disposed on a side of the substrate away from the piezoelectric material layer.

3. The structure of the silicon-based cantilever beam MEMS piezoelectric microphone according to claim 2, characterized in that: The structure further includes a silicon layer, which is disposed on a side of the first electrode layer away from the piezoelectric material layer.

4. The structure of the silicon-based cantilever beam MEMS piezoelectric microphone according to claim 3, characterized in that: The structure also includes a silicon oxide portion and a device layer silicon portion. The silicon oxide portion is arranged on a side of the substrate close to the first electrode layer, and the device layer silicon portion is placed on a side of the silicon oxide portion away from the substrate and on a side of the first electrode layer away from the piezoelectric material layer.

5. A silicon-based cantilever beam MEMS piezoelectric microphone device, characterized in that: The device includes a digital-to-analog conversion device and the structure of a silicon-based cantilever beam MEMS piezoelectric microphone as described in any one of claims 1 to 4, wherein the positive and negative electrodes of the digital-to-analog conversion device are electrically connected to the first electrode layer and the second electrode layer of the structure, respectively, and are used to convert the voltage signals output by the first electrode layer and the second electrode layer into digital signals.

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