MEMS sensor, preparation method of MEMS sensor and electronic equipment

Abstract

The embodiment of the invention discloses an MEMS sensor, a preparation method of the MEMS sensor and electronic equipment, the MEMS sensor comprises a silicon substrate, a vibrating diaphragm, an insulating layer and a back electrode, and the silicon substrate is provided with a sound hole; the vibrating diaphragm is arranged on the silicon substrate, the vibrating diaphragm comprises a first area and a second area which are connected, and at least the first area is opposite to the sound hole; the insulating layer is arranged between the second area and the silicon substrate, so that the vibrating diaphragm is in insulated connection with the silicon substrate; the back electrode is arranged on the vibrating diaphragm, and a first gap is arranged between the back electrode and the vibrating diaphragm. Therefore, the insulating layer is clamped between the second area and the silicon substrate, so that the vibrating diaphragm and the silicon substrate are connected in an insulating manner, abnormities such as short circuit caused by water entering the sound hole can be avoided, the failure risk of the MEMS sensor is reduced, and the service life of the MEMS sensor is prolonged.

Description

Technical Field

[0001] The present invention relates to the field of micro-electromechanical technology, and more specifically, to a MEMS sensor, a method for preparing a MEMS sensor, and an electronic device. Background Art

[0002] MEMS sensors are structures manufactured using micro-electro-mechanical systems (MEMS) technology. Simply put, MEMS sensors use semiconductor materials to form capacitors, integrating them onto tiny silicon wafers. Products made using MEMS technology are characterized by their small size and high sensitivity. MEMS sensors also have excellent radio frequency interference (RFI) and electromagnetic interference (EMI) suppression capabilities.

[0003] However, for current MEMS sensor structures, most of them place the diaphragm directly on the substrate, which often poses the risk of water entering the sound hole and causing a short circuit between the two, thereby increasing the risk of MEMS sensor failure. Summary of the Invention

[0004] In view of the above-mentioned shortcomings of the prior art, an object of the present invention is to provide a MEMS sensor, a method for manufacturing a MEMS sensor, and a new technical solution for electronic equipment.

[0005] According to one aspect of the present invention, a MEMS sensor is provided.

[0006] The MEMS sensor comprises:

[0007] A silicon substrate, wherein an acoustic hole is formed on the silicon substrate;

[0008] a diaphragm, the diaphragm being provided on the silicon substrate, the diaphragm comprising a first region and a second region connected to each other, at least the first region being opposite to the sound hole;

[0009] an insulating layer, wherein the insulating layer is provided between the second region and the silicon substrate to provide an insulated connection between the diaphragm and the silicon substrate;

[0010] A back pole is provided on the diaphragm, and a first gap is formed between the back pole and the diaphragm.

[0011] Optionally, the insulating layer has a ring-shaped structure, and the inner diameter of the insulating layer is not less than the diameter of the sound hole.

[0012] Optionally, the diaphragm includes a first diaphragm and a second diaphragm, one of the first diaphragm and the second diaphragm is provided on the back pole, and the other of the first diaphragm and the second diaphragm is insulated and connected to the silicon substrate via the insulating layer.

[0013] Optionally, the first diaphragm and the second diaphragm both include the first region and the second region, the first region is located in the middle, the second region surrounds the circumference of the first region, and the second region of the first diaphragm is connected to the back pole, and the second region of the second diaphragm is connected to the insulating layer.

[0014] Optionally, the first diaphragm and the second diaphragm both include the first region and the second region, the second region of the first diaphragm is connected to the back pole, the second region of the second diaphragm is connected to the insulating layer, and the first diaphragm and the second diaphragm are respectively cantilevered.

[0015] Optionally, the first diaphragm includes a first fixed end and a first free end, the first fixed end is located in the second region and connected to the back electrode, and the first free end is located in the first region and forms a second gap with the silicon substrate;

[0016] The second diaphragm includes a second fixed end and a second free end. The second fixed end is located in the second region and connected to the insulating layer. The second free end is located in the first region and forms a third gap with the silicon substrate.

[0017] Optionally, a partition is further included, and the partition is provided on the side of the insulating layer facing the second free end, and / or the partition is provided on the side of the silicon substrate facing the first free end, and the partition can block at least one of the second gap and the third gap.

[0018] Optionally, along the extension direction of the partition, the size of the partition is not smaller than the size of the insulating layer.

[0019] Optionally, both sides of the back pole have support parts, and during operation, the support parts can abut against the first area.

[0020] Optionally, a circuit structure is formed inside the silicon substrate, and the diaphragm and the back electrode are electrically connected to the circuit structure respectively.

[0021] According to another aspect of the present invention, a method for preparing a MEMS sensor is provided, comprising:

[0022] preparing a silicon substrate, and opening an acoustic hole in the silicon substrate;

[0023] Manufacturing an insulating layer, and disposing the insulating layer on the silicon substrate;

[0024] Manufacturing a diaphragm, the diaphragm comprising a first region and a second region connected to each other, at least the first region being opposite to the sound hole, and connecting the second region to the insulating layer to ensure an insulated connection between the diaphragm and the silicon substrate;

[0025] A back pole is manufactured and arranged on the diaphragm, with a first gap formed between the back pole and the diaphragm.

[0026] Optionally, the surface of the silicon substrate is formed by insulation treatment.

[0027] According to yet another aspect of the present invention, an electronic device is provided, comprising the above-mentioned MEMS sensor.

[0028] One technical effect of the embodiments of the present disclosure is:

[0029] The MEMS sensor includes a silicon substrate, a diaphragm, an insulating layer, and a back electrode. The silicon substrate is provided with an acoustic hole. The diaphragm is disposed on the silicon substrate and includes a first region and a second region connected to each other, with at least the first region facing the acoustic hole. The insulating layer is disposed between the second region and the silicon substrate to insulate the diaphragm from the silicon substrate. The back electrode is disposed on the diaphragm, with a first gap between the back electrode and the diaphragm. Thus, the insulating layer is sandwiched between the second region and the silicon substrate, insulating the diaphragm from the silicon substrate. This prevents abnormalities such as short circuits caused by water ingress into the acoustic hole, reduces the risk of MEMS sensor failure, and extends the service life of the MEMS sensor.

[0030] Further features and advantages of the present invention will become apparent from the following detailed description of exemplary embodiments of the present invention with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the present invention and, together with the description, serve to explain the principles of the present invention.

[0032] Figure 1 is a schematic diagram of a MEMS sensor according to an embodiment of the present disclosure;

[0033] Figure 2 FIG. 4 is a schematic diagram of another MEMS sensor according to an embodiment of the present disclosure.

[0034] Description of reference numerals:

[0035] 1. Silicon substrate; 11. Acoustic hole; 2. Diaphragm; 21. First region; 22. Second region; 3. Insulating layer; 4. Back electrode; 41. Support part; 5. Partition. DETAILED DESCRIPTION

[0036] Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that unless otherwise specifically stated, the relative arrangement of components and steps, numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present invention.

[0037] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the invention, its application, or uses.

[0038] Techniques and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the techniques and equipment should be considered part of the specification.

[0039] In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not limiting. Therefore, other examples of the exemplary embodiments may have different values.

[0040] It should be noted that like reference numerals and letters refer to like items in the following figures, and therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0041] An embodiment of the present invention provides a MEMS sensor, which may be a MEMS microphone or a MEMS speaker.

[0042] like Figure 1 and Figure 2 As shown, the MEMS sensor provided by the embodiment of the present invention includes:

[0043] A silicon substrate 1, wherein an acoustic hole 11 is formed on the silicon substrate 1;

[0044] a diaphragm 2, the diaphragm 2 being disposed on the silicon substrate 1, the diaphragm 2 including a first region 21 and a second region 22 connected to each other, at least the first region 21 being opposite to the acoustic hole 11;

[0045] an insulating layer 3, wherein the insulating layer 3 is provided between the second region 22 and the silicon substrate 1, so as to provide an insulated connection between the diaphragm 2 and the silicon substrate 1;

[0046] The back pole 4 is provided on the diaphragm 2 , and a first gap is formed between the back pole 4 and the diaphragm 2 .

[0047] Specifically, in embodiments of the present invention, high-purity single-crystal silicon can be selected as the substrate material, which is cleaned and surface treated through semiconductor processes to remove surface impurities and oxides. Subsequently, acoustic holes 11 are formed in the silicon substrate 1 using photolithography, wet etching, or dry etching techniques. The shape and distribution of acoustic holes 11 can be optimized based on the specific application scenario. Common shapes include circular, rectangular, or arrayed holes, which can effectively transmit sound waves to the interior of the MEMS sensor.

[0048] Silicon substrate 1 serves as the structural foundation of the MEMS sensor, supporting and arranging structures such as the diaphragm 2 and backplate 4, and ensuring the structural stability of the MEMS sensor. Furthermore, a circuit structure can be formed within silicon substrate 1, to which the diaphragm 2 and backplate 4 are electrically connected. This protects the electrical connections, preventing short circuits and other anomalies caused by water intrusion due to exposed electrical connections, and thus improving the reliability of the MEMS sensor.

[0049] In addition, the surface of the silicon substrate 1 can be insulated by heat treatment, plating and other chemical methods or physical methods to form protection, so that the connection parts between the diaphragm 2 and the back pole 4 and the silicon substrate 1 have an insulating layer, so that the diaphragm 2 and the back pole 4 are insulated and connected to the silicon substrate 1 respectively, and abnormalities such as short circuits caused by water ingress can be avoided, thereby reducing the failure risk of the MEMS sensor.

[0050] like Figure 1 and Figure 2 As shown, the diaphragm 2 includes a first area 21 and a second area 22 , the first area 21 is a sensing area, and the second area 22 is a supporting area.

[0051] The first region 21 faces the acoustic hole 11 and is the primary area of ​​action for sound waves. Because the first region 21 of the diaphragm 2 faces the acoustic hole 11 on the silicon substrate 1 directly, sound waves can more effectively pass through the acoustic hole 11 and act on the diaphragm 2, causing it to vibrate. This direct coupling reduces energy loss during sound wave transmission, thereby improving the acoustic sensitivity of the MEMS sensor. To enhance the sensitivity and stability of the diaphragm 2, microstructures such as wrinkles, protrusions, or a patterned surface can be designed on the surface of the first region 21 to increase the effective vibration area of ​​the first region 21 and improve the acoustic performance of the MEMS sensor.

[0052] The second region 22 is isolated from the silicon substrate 1 by an insulating layer 3. Interposing the insulating layer 3 between the second region 22 and the silicon substrate 1 provides an insulated connection between the diaphragm 2 and the silicon substrate 1, thereby preventing abnormalities such as short circuits caused by water ingress into the acoustic hole 11. This reduces the risk of MEMS sensor failure, extends the service life of the MEMS sensor, enhances the electrical stability of the MEMS sensor, and reduces noise and errors caused by electrical coupling. The insulating layer 3 can be made of silicon dioxide, silicon nitride, or a high molecular polymer. The thickness of the insulating layer 3 must be precisely controlled to ensure electrical isolation between the diaphragm 2 and the silicon substrate 1 while not affecting the mechanical properties of the MEMS sensor.

[0053] Specifically, the back electrode 4 can be deposited on the diaphragm 2 by physical vapor deposition, electroplating, or other thin film deposition techniques. A certain first gap is maintained between the back electrode 4 and the diaphragm 2. The size of the first gap can be precisely controlled according to specific needs to meet the sensitivity, frequency response, and other characteristics of different MEMS sensors, thereby facilitating adaptation to different applications.

[0054] To ensure uniformity and stability of the first gap, a sacrificial layer technique can be used. That is, before depositing the back electrode 4, a layer of sacrificial material is first deposited on the diaphragm 2 as a sacrificial layer. The back electrode 4 is then deposited, and finally the sacrificial layer is removed by chemical etching or heat treatment to form the desired first gap.

[0055] Optionally, the insulating layer 3 is an annular structure, and the inner diameter of the insulating layer 3 is not less than the diameter of the sound hole 11 .

[0056] Specifically, the insulating layer 3 can be a circular ring, a rectangular ring or other annular structures, through which an insulating connection between the diaphragm 2 and the silicon substrate 1 can be achieved, that is, the annular structure can insulate and seal the connection between the diaphragm 2 and the silicon substrate 1, thereby avoiding abnormalities such as short circuits caused by water ingress, and reducing the failure risk of the MEMS sensor.

[0057] Among them, the outer wall of the insulating structure is arranged to fit with the silicon substrate 1, which can facilitate the installation and fixation of the insulating structure; the inner wall of the insulating structure is arranged not to exceed the sound hole 11, which can avoid the setting of the insulating structure causing interference to the sound hole 11, thereby ensuring the reliable transmission of sound waves.

[0058] Optionally, the diaphragm 2 includes a first diaphragm and a second diaphragm, one of the first diaphragm and the second diaphragm is provided on the back pole 4 , and the other of the first diaphragm and the second diaphragm is insulated and connected to the silicon substrate 1 through the insulating layer 3 .

[0059] like Figure 1 and Figure 2As shown, the diaphragm 2 can adopt a dual-diaphragm design. One of the first and second diaphragms serves as the lower diaphragm, which is insulated and connected to the silicon substrate 1 via an insulating layer 3. This ensures that the connection between the diaphragm 2 and the silicon substrate 1 is insulated and sealed, thereby preventing abnormalities such as short circuits caused by water ingress and reducing the risk of MEMS sensor failure. The other of the first and second diaphragms serves as the upper diaphragm, which is connected to the back electrode 4, thus forming a dual-diaphragm sensing structure.

[0060] Optionally, the first diaphragm and the second diaphragm both include the first region 21 and the second region 22, the first region 21 is located in the middle, the second region 22 surrounds the first region 21, and the second region 22 of the first diaphragm is connected to the back pole 4, and the second region 22 of the second diaphragm is connected to the insulating layer 3.

[0061] like Figure 1 As shown, both the first and second diaphragms are connected by fixing their ends. For example, the first diaphragm is located at the top and includes a first region 21 and a second region 22. The first region 21 is located in the center, and the second region 22 surrounds the first region 21. The first region 21 is opposite the sound hole 11, and the second region 22 is connected to the back electrode 4 to fix the first diaphragm. An air gap is formed between the first diaphragm and the back electrode 4.

[0062] The second diaphragm is located at the bottom, and the second diaphragm also includes a first area 21 and a second area 22. The first area 21 is located in the center, and the second area 22 surrounds the outer periphery of the first area 21. The first area 21 is opposite to the sound hole 11, and the second area 22 is connected to the insulating layer 3 to fix the second diaphragm.

[0063] Optionally, the first diaphragm and the second diaphragm both include the first region 21 and the second region 22, the second region 22 of the first diaphragm is connected to the back pole 4, the second region 22 of the second diaphragm is connected to the insulating layer 3, and the first diaphragm and the second diaphragm are respectively cantilevered.

[0064] like Figure 2 As shown, both the first and second diaphragms are connected using a single-end fixed connection. For example, the first diaphragm is located at the top and includes a first region 21 and a second region 22. The first and second regions 21 and 22 are adjacent to each other, with at least the first region 21 facing the sound hole 11. The second region 22 is connected to the back plate 4 and realizes the single-end fixed connection of the first diaphragm, and an air gap is formed between the first diaphragm and the back plate 4.

[0065] The second diaphragm is located below and also includes a first area 21 and a second area 22 . The first area 21 and the second area 22 are adjacent to each other. At least the first area 21 is opposite to the sound hole 11 . The second area 22 is connected to the insulating layer 3 and fixes the second diaphragm.

[0066] The single-ended fixing of the first diaphragm and the second diaphragm can, on the one hand, reduce the stress sensitivity of the first diaphragm and the second diaphragm, thereby improving the reliability of the MEMS sensor; on the other hand, the single-ended fixing can also save the connection process of the first diaphragm and the second diaphragm, thereby reducing production costs.

[0067] Optionally, the first diaphragm includes a first fixed end and a first free end, the first fixed end is located in the second region 22 and connected to the back electrode 4, and the first free end is located in the first region 21 and forms a second gap with the silicon substrate 1;

[0068] The second diaphragm includes a second fixed end and a second free end. The second fixed end is located in the second region 22 and connected to the insulating layer 3 . The second free end is located in the first region 21 and forms a third gap with the silicon substrate 1 .

[0069] like Figure 2 As shown, the first fixed end and the first free end are located on either side of the first diaphragm. The first fixed end of the first diaphragm is connected to the back electrode 4, and a second gap is formed between the first free end of the first diaphragm and the silicon substrate 1. The second fixed end and the second free end are located on either side of the second diaphragm. The second fixed end of the second diaphragm is connected to the insulating layer 3, and a third gap is formed between the second free end of the second diaphragm and the silicon substrate 1. The second fixed end can be arranged opposite the first free end, and the first fixed end can be arranged opposite the second free end, with the second gap and the third gap located on either side, respectively, to facilitate assembly.

[0070] Optionally, a partition 5 is further included, and the partition 5 is provided on the side of the insulating layer 3 facing the second free end, and / or the partition 5 is provided on the side of the silicon substrate 1 facing the first free end, and the partition 5 can block at least one of the second gap and the third gap.

[0071] like Figure 2 As shown, a partition 5 can be provided on the side of the insulating layer 3 facing the second free end. The partition 5 can shield the third gap and prevent water or other foreign matter from entering the MEMS sensor through the third gap at the second free end, thereby protecting the internal structure of the MEMS sensor and extending the service life of the MEMS sensor.

[0072] A partition 5 can also be provided on the side of the silicon substrate 1 facing the first free end. The partition 5 can shield the second gap and prevent water or other foreign matter from entering the MEMS sensor through the second gap at the first free end, thereby protecting the internal structure of the MEMS sensor and extending the service life of the MEMS sensor. Depending on the actual shielding requirements, the partition 5 can be configured as a rectangular plate, a circular plate, or other plate-shaped structure. The extension direction of the partition 5 can be consistent with the extension direction of the diaphragm 2, which also facilitates a reliable shielding effect.

[0073] Optionally, along the extension direction of the partition 5, the size of the partition 5 is not less than the size of the insulating layer 3. Figure 2 As shown, the size of the partition 5 is not less than the size of the insulating layer 3, that is, the partition 5 is flush with the insulating layer 3, or the partition 5 extends beyond the insulating layer 3, which can ensure the reliable shielding effect of the partition 5 while also protecting the insulating layer 3.

[0074] Optionally, both sides of the back pole 4 have support portions 41 , respectively, and the support portions 41 can abut against the first region 21 during operation.

[0075] like Figure 2 As shown, during the vibration of the first and second diaphragms, the support portion 41 can abut against the first region 21 to support the first and second diaphragms. Depending on the actual design, the support portion 41 may include a plurality of discretely arranged protrusions or at least one support ring.

[0076] Optionally, a circuit structure is formed inside the silicon substrate 1 , and the diaphragm 2 and the back electrode 4 are electrically connected to the circuit structure respectively to enable transmission of electrical signals.

[0077] An embodiment of the present invention further provides a method for preparing the above-mentioned MEMS sensor, comprising:

[0078] A silicon substrate 1 is manufactured, and an acoustic hole 11 is formed on the silicon substrate 1;

[0079] Producing an insulating layer 3, and disposing the insulating layer 3 on the silicon substrate 1;

[0080] A diaphragm 2 is manufactured, wherein the diaphragm 2 includes a first region 21 and a second region 22 connected to each other, wherein at least the first region 21 is opposite to the acoustic hole 11, and the second region 22 is connected to the insulating layer 3 to ensure an insulated connection between the diaphragm 2 and the silicon substrate 1;

[0081] A back pole 4 is manufactured and disposed on the diaphragm 2 , with a first gap formed between the back pole 4 and the diaphragm 2 .

[0082] Silicon substrate 1 serves as the structural foundation of the MEMS sensor, supporting and arranging structures such as diaphragm 2 and backplate 4, and ensuring the structural stability of the MEMS sensor. Furthermore, a circuit structure can be formed within silicon substrate 1, to which diaphragm 2 and backplate 4 are electrically connected. This provides both electrical connections and protection, preventing short circuits and other anomalies caused by water intrusion due to exposed electrical connections, thereby improving the reliability of the MEMS sensor.

[0083] The insulating layer 3 is sandwiched between the second region 22 and the silicon substrate 1 to provide an insulated connection between the diaphragm 2 and the silicon substrate 1. This prevents abnormalities such as short circuits caused by water ingress into the acoustic hole 11, reduces the risk of MEMS sensor failure, extends the service life of the MEMS sensor, enhances the electrical stability of the MEMS sensor, and reduces noise and errors caused by electrical coupling. The insulating layer 3 can be made of silicon dioxide, silicon nitride, or a high molecular polymer. The thickness of the insulating layer 3 must be precisely controlled to ensure electrical isolation between the diaphragm 2 and the silicon substrate 1 while not affecting the mechanical properties of the MEMS sensor.

[0084] Optionally, the surface of the silicon substrate 1 is formed by insulation treatment.

[0085] Specifically, the surface of the silicon substrate 1 can be insulated by chemical methods such as heat treatment and plating, or physical methods to form protection, so that the connection parts between the diaphragm 2 and the back pole 4 and the silicon substrate 1 have an insulating layer, so that the diaphragm 2 and the back pole 4 are insulated and connected to the silicon substrate 1 respectively, and abnormalities such as short circuits caused by water ingress can be avoided, thereby reducing the failure risk of the MEMS sensor.

[0086] The present invention also provides an electronic device comprising the above-mentioned MEMS sensor, wherein the electronic device includes but is not limited to a mobile phone, a tablet, and a computer.

[0087] The above embodiments focus on the differences between the various embodiments. As long as the different optimization features between the various embodiments are not contradictory, they can be combined to form a better embodiment. Considering the simplicity of the text, they will not be repeated here.

[0088] Although some specific embodiments of the present invention have been described in detail by way of example, it should be understood by those skilled in the art that the above examples are for illustration only and are not intended to limit the scope of the present invention. It should be understood by those skilled in the art that modifications may be made to the above embodiments without departing from the scope and spirit of the present invention. The scope of the present invention is defined by the appended claims.

Claims

1. A MEMS sensor, characterized in that: include: A silicon substrate (1), wherein a sound hole (11) is provided on the silicon substrate (1); A diaphragm (2), the diaphragm (2) being arranged on the silicon substrate (1), the diaphragm (2) comprising a first region (21) and a second region (22) which are connected, and at least the first region (21) is opposite to the sound hole (11); an insulating layer (3), wherein the insulating layer (3) is provided between the second region (22) and the silicon substrate (1), so as to provide an insulating connection between the diaphragm (2) and the silicon substrate (1); A back pole (4), the back pole (4) is arranged on the diaphragm (2), and a first gap is provided between the back pole (4) and the diaphragm (2).

2. The MEMS sensor according to claim 1, characterized in that: The insulating layer (3) is in an annular structure, and the inner diameter of the insulating layer (3) is not less than the diameter of the sound hole (11).

3. The MEMS sensor according to claim 1, characterized in that: The diaphragm (2) comprises a first diaphragm and a second diaphragm, one of the first diaphragm and the second diaphragm is arranged on the back pole (4), and the other of the first diaphragm and the second diaphragm is insulated and connected to the silicon substrate (1) via the insulating layer (3).

4. The MEMS sensor according to claim 3, characterized in that: The first diaphragm and the second diaphragm both comprise the first region (21) and the second region (22), the first region (21) being located in the middle, the second region (22) surrounding the first region (21), and the second region (22) of the first diaphragm being connected to the back pole (4), and the second region (22) of the second diaphragm being connected to the insulating layer (3).

5. The MEMS sensor according to claim 3, characterized in that: The first diaphragm and the second diaphragm both comprise the first region (21) and the second region (22); the second region (22) of the first diaphragm is connected to the back pole (4); the second region (22) of the second diaphragm is connected to the insulating layer (3); and the first diaphragm and the second diaphragm are respectively cantilevered.

6. The MEMS sensor according to claim 5, characterized in that: The first diaphragm comprises a first fixed end and a first free end, the first fixed end is located in the second region (22) and connected to the back electrode (4), and the first free end is located in the first region (21) and forms a second gap with the silicon substrate (1); The second diaphragm comprises a second fixed end and a second free end, the second fixed end is located in the second region (22) and connected to the insulating layer (3), and the second free end is located in the first region (21) and forms a third gap with the silicon substrate (1).

7. The MEMS sensor according to claim 6, characterized in that: The invention also comprises a partition (5), wherein the partition (5) is provided on the side of the insulating layer (3) facing the second free end, and / or the partition (5) is provided on the side of the silicon substrate (1) facing the first free end, and the partition (5) is capable of shielding at least one of the second gap and the third gap.

8. The MEMS sensor according to claim 7, characterized in that: Along the extension direction of the partition (5), the size of the partition (5) is not less than the size of the insulating layer (3).

9. The MEMS sensor according to claim 5, characterized in that: The back pole (4) has support portions (41) on both sides respectively, and the support portions (41) can abut against the first region (21) during operation.

10. The MEMS sensor according to claim 1, characterized in that: A circuit structure is formed inside the silicon substrate (1), and the diaphragm (2) and the back electrode (4) are respectively electrically connected to the circuit structure.

11. A method for preparing a MEMS sensor according to any one of claims 1 to 10, characterized in that: include: Manufacturing a silicon substrate, and opening an acoustic hole on the silicon substrate; Manufacturing an insulating layer, and disposing the insulating layer on the silicon substrate; Manufacturing a diaphragm, wherein the diaphragm comprises a first region and a second region connected to each other, wherein at least the first region is opposite to the sound hole, and the second region is connected to the insulating layer, so that the diaphragm is insulated and connected to the silicon substrate; A back pole is manufactured and arranged on the diaphragm, with a first gap formed between the back pole and the diaphragm.

12. The preparation method according to claim 11, characterized in that: The surface of the silicon substrate is formed by insulation treatment.

13. An electronic device, characterized in that: A MEMS sensor comprising any one of claims 1 to 10.

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