Bidirectional switching device, preparation method thereof and electronic equipment

Abstract

The invention discloses a bidirectional switching device, a preparation method thereof and electronic equipment. The bidirectional switching device comprises a substrate, a channel layer, a first source electrode, a second source electrode, a first grid electrode and a second grid electrode, wherein the substrate and the channel layer are sequentially arranged; the first source electrode and the second source electrode are located at the two ends of the channel layer and are bilaterally symmetrical; the dielectric layer is arranged on the channel layer between the first grid electrode and the second grid electrode; the dielectric layer comprises an inclined mesa structure which is far away from the middle area of the channel layer, and further comprises a first field plate and a second field plate which are arranged on the left side and the right side of the inclined mesa structure, so that the first field plate and the second field plate respectively wrap exposed parts on the left side and the right side of the mesa structure. The first field plate is not in contact with the second field plate. The inclined mesa structure and the corresponding field plate of the bidirectional switching device can improve the electric field uniformity between the adjacent grids, thereby shortening the distance between the grids, reducing the cost and improving the performance.

Description

Technical Field

[0001] This application relates to the field of semiconductor device technology, and in particular to a bidirectional switching device and its fabrication method, and electronic equipment. Background Technology

[0002] A bidirectional switch can block current in both directions and is often referred to as an AC switch or a four-quadrant switch. Typically, a bidirectional switch consists of two SiMOSFET or GaN HEMT devices connected in a common-source or common-drain configuration. Due to the horizontal structure of HEMTs, two devices can be combined into one. Using a common-drain connection eliminates the need for a drain electrode and allows for a shared voltage-bearing region, ultimately reducing the device area.

[0003] Bidirectional switching devices require the use of field plate structures to make the electric field in the channel as uniform as possible, thereby improving the breakdown voltage of the device. However, electric field peaks appear at the edges of the field plate, and the electric field between two adjacent gates is not uniform enough, which also limits the reduction of the spatial distance between two adjacent gates.

[0004] Therefore, there is an urgent need for a bidirectional switching device and its fabrication method, as well as electronic equipment, to solve the above-mentioned technical problems. Summary of the Invention

[0005] This application provides a bidirectional switching device and its fabrication method, as well as an electronic device, which solves the problem that the field plate structure of existing bidirectional switching devices limits the reduction of the spatial distance between two adjacent gates.

[0006] To achieve the above objectives, this application employs the following technical solution:

[0007] This application provides a bidirectional switching device, including a substrate and a channel layer disposed sequentially, and a first source, a second source, a first gate, and a second gate located at both ends of the channel layer and symmetrically arranged to the left and right respectively.

[0008] It also includes a dielectric layer disposed on the channel layer between the first gate and the second gate; the dielectric layer includes an inclined mesa structure away from the middle region of the channel layer, and also includes a first field plate and a second field plate on the left and right sides of the inclined mesa structure, such that the first field plate and the second field plate respectively cover the exposed portions on the left and right sides of the mesa structure, and the first field plate and the second field plate do not contact each other.

[0009] In one embodiment of this application, the inclined platform has a left-right symmetrical structure, and the cross-sectional shape of the inclined platform structure is any one of the following: arc, triangle, trapezoid, or trapezoid with arc sides.

[0010] In one embodiment of this application, the first field plate and the second field plate are respectively connected to the first gate and the second gate of the bidirectional switching device; or the first field plate and the second field plate are respectively connected to the first source and the second source of the bidirectional switching device.

[0011] This application also provides a method for fabricating a bidirectional switching device, the method comprising:

[0012] A bidirectional switching device without a field plate is provided. The bidirectional switching device includes a substrate, a channel layer, and a first source, a second source, a first gate, and a second gate located at both ends of the channel layer and symmetrically positioned to the left and right, respectively; it also includes a dielectric layer disposed on the channel layer between the first gate and the second gate.

[0013] A symmetrical inclined platform structure is fabricated in the middle region of the dielectric layer away from the channel layer;

[0014] A first field plate and a second field plate are fabricated on the left and right sides of the inclined mesa structure, such that the first field plate and the second field plate respectively cover the exposed portions on the left and right sides of the mesa structure; wherein the first field plate and the second field plate do not contact each other, and the first field plate and the second field plate are located in the region between the first gate and the second gate.

[0015] In one embodiment of this application, the step of fabricating a symmetrical inclined mesa structure in the middle region of the dielectric layer away from the channel layer is specifically as follows:

[0016] S201. Photoresist is deposited on the dielectric layer, which is obtained by deposition on the channel layer;

[0017] S202. Heat the photoresist at a preset temperature so that the shape of the photoresist meets the preset pattern;

[0018] S203. Dry etching of the dielectric layer and photoresist to transfer the shape of the photoresist onto the dielectric layer.

[0019] In one embodiment of this application, the etching rate ratio of the photoresist to the dielectric layer is 1:X, where X is any one of 1, less than 1, or greater than 1. This etching rate ratio is used to control the shape of the photoresist transferred onto the dielectric layer. During the etching process, the process conditions can be adjusted as needed to make X change over time.

[0020] In one embodiment of this application, the cross-sectional shape of the inclined platform structure is any one of the following: arc, triangle, trapezoid, or trapezoid with arc sides.

[0021] In one embodiment of this application, in step S1, the width of the photoresist is 1µm to 40µm, and the thickness of the photoresist is 0.2µm to 10µm; and / or,

[0022] In step S2, the preset temperature is 75℃~250℃, and the heating time is 30s~3h.

[0023] This application also provides an electronic device comprising any of the bidirectional switching devices described above.

[0024] In one embodiment of this application, the electronic device includes any one of a photovoltaic inverter, a server power supply, a motor drive, a mobile phone, a laptop computer, a tablet computer, and a wearable electronic device.

[0025] Compared with existing technologies, the bidirectional switching device and its fabrication method provided in this application, along with the electronic device, create a symmetrical inclined mesa structure in the middle region of the dielectric layer. A first field plate and a second field plate are fabricated on either side of the inclined mesa structure, which helps to further regulate the electric field, prevent peak values ​​at the field plate edges, improve the electric field distribution, and reduce electric field concentration. Due to the symmetry of the field plates and the design of the inclined mesa structure, the electric field distribution in the LG1G2 region (i.e., the region between the first and second gates) is more uniform. Therefore, by simplifying the field plate structure, the number of metal deposition and dielectric etching steps required for multilayer field plates is reduced, thereby lowering manufacturing costs. The uniform distribution of the electric field helps improve the device's breakdown voltage, enhancing its performance and reliability. The simplified field plate structure reduces the device's footprint, facilitating miniaturization. Utilizing the symmetry of the first and second gates simplifies the process steps, making production easier and improving efficiency. The tilted mesa structure of the field plate helps optimize the electric field distribution, reducing electric field peaks and improving the device's electrical characteristics. By avoiding special processes such as grayscale exposure, this technology is more suitable for mass production, helping to reduce unit costs. In summary, this method can improve the electric field uniformity between adjacent gates, thereby reducing the distance between them, lowering costs, and improving performance. Furthermore, the method utilizes gate symmetry to simplify the process steps, making it easy to implement. Compared to multilayer field plates, it can further reduce device manufacturing costs, achieving the dual goals of cost-effectiveness and performance improvement. Attached Figure Description

[0026] Figure 1a A schematic diagram showing two HEMT devices configured as a bidirectional switch using a common-drain configuration, provided for related technologies;

[0027] Figure 1b A schematic diagram of the structure of HEMT provided for related technologies;

[0028] Figure 1c A schematic diagram of a bidirectional switch with a common-drain structure provided for related technologies;

[0029] Figure 2a A cross-sectional schematic diagram of a bidirectional switching device provided in an embodiment of this application;

[0030] Figure 2b A top view schematic diagram of a bidirectional switching device provided in an embodiment of this application;

[0031] Figure 3 A schematic flowchart illustrating a method for fabricating a bidirectional switching device according to an embodiment of this application;

[0032] Figure 4 This application provides a schematic diagram of a process for manufacturing an inclined platform structure.

[0033] Figures 5a to 5d This application provides a schematic diagram of a structure for fabricating an inclined platform structure.

[0034] Figures 6a to 6c Schematic diagrams showing different morphologies of the inclined platform structure provided in the embodiments of this application;

[0035] Figures 7a to 7d This is a simplified flowchart illustrating the fabrication process of a bidirectional switch, as provided in an embodiment of this application.

[0036] Illustration: 10, substrate; 20, channel layer; 30, dielectric layer; 31, tilted mesa structure; S1, first source; S2, second source; G1, first gate; G2, second gate; FP1, first field plate; FP2, second field plate; PR, photoresist. Detailed Implementation

[0037] To facilitate understanding of this application, a more complete description will be provided below with reference to the accompanying drawings. Preferred embodiments of this application are shown in the drawings. However, this application can be implemented in many other different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of this application.

[0038] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the specification of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0039] In related technologies, a bidirectional switch can consist of two Si MOSFETs or GaN HEMT devices connected in a common-source or common-drain configuration. Due to the horizontal structure of the HEMT, the two devices can be combined into one. See also Figure 1a , Figure 1b and Figure 1c , Figure 1a This diagram illustrates a bidirectional switch composed of two HEMT devices arranged in a common-drain configuration, provided for related technologies. Figure 1b A schematic diagram of the HEMT structure provided for related technologies. Figure 1c A schematic diagram of a bidirectional switch with a common-drain structure provided for related technologies.

[0040] The common-drain connection combines two HEMT devices into one, reducing the number of components used in the circuit, saving packaging costs, simplifying the circuit, and reducing parasitic parameters. Furthermore, theoretically, it can reduce the area of ​​the semiconductor used, further reducing costs and improving performance. See also Figure 1b The length of a single HEMT device unit is: L(HEMT) = L0 + LD + LGD. According to... Figure 1a The proposed scheme, where two HEMT devices are combined to form a bidirectional switch, results in a total unit size of L(2HEMT) = 2 * LHEMT. According to... Figure 1c The proposed scheme has a single bidirectional device unit length of L(AC) = L0*2 + LG1G2.

[0041] Since the resistance of the device is directly proportional to the unit length and inversely proportional to the total gate width W, the above two schemes have R(AC)~L(AC) / W(AC) and R(2HEMT)~L(2HEMT) / W(2HEMT).

[0042] Because in practical circuits, it is required that... Figure 1a and Figure 1c For both corresponding schemes, the total on-resistance is the same, so we can obtain W(AC) / W(2HEMT)=L(AC) / L(2HEMT)

[0043] In both schemes, the total area of ​​the semiconductor device is AREA(AC) = L(AC) * W(AC); AREA(2HEMT) = L(2HEMT) * W(2HEMT).

[0044] Considering the two schemes, the area ratio of the semiconductor devices is: RATIO = AREA(AC) / AREA(2HEMT). Substituting the area, we get RATIO = ((L0*2 + LG1G2) / (2*L0 + 2*LD + 2*LGD))**2. Assuming an ideal situation where the dimensions of L0 and LD are negligible; and with the same device voltage specifications, the voltage-bearing portion LG1G2 can theoretically be equal to LGD. Figure 1c The total area of ​​the device will be Figure 1a The total area of ​​the two devices is 1 / 4. In practice, reducing LG1G2 and L(AC) will bring two benefits:

[0045] a) Reduced semiconductor area (AREA(AC)) leads to lower costs;

[0046] b) As the total gate width W(AC) decreases, the parasitic capacitance of the device also decreases, thereby reducing switching losses.

[0047] In other words, horizontal devices require field plate structures to make the electric field in the channel as uniform as possible, thereby improving the breakdown voltage of the device. Typically, 2-3 layers of field plates are needed, and their fabrication process involves multiple metal depositions and dielectric etching steps, which is detrimental to cost reduction and performance improvement. Multilayer field plates also occupy a significant amount of space, limiting the reduction in size of LG1G2. Furthermore, electric field peaks appear at the edges of the field plates, therefore... Figure 1c The electric field is still not uniform enough throughout the entire LG1G2, which also limits the shrinkage of LG1G2.

[0048] Clearly, in existing bidirectional switching devices, the electric field between the entire LG1G2 layer is still not uniform enough, failing to address the problem of the field plate structure limiting the reduction of the spatial distance between adjacent gates. This application proposes a bidirectional switching device that uses a tilted field plate to alleviate the problem of uneven electric field in multilayer field plates. Furthermore, it proposes a fabrication method for the bidirectional switching device that eliminates the need for special processes such as grayscale exposure to create the tilted field plate, thus facilitating mass production and reducing device costs.

[0049] Example 1

[0050] See Figure 3 , Figure 3 This is a schematic flowchart illustrating a method for fabricating a bidirectional switching device according to an embodiment of this application. This embodiment provides a method for fabricating a bidirectional switching device, used to prepare such a device... Figure 2a , Figure 2b The bidirectional switching device shown.

[0051] The fabrication method of the bidirectional switching device includes steps S101 to S103.

[0052] S101. Provide a bidirectional switching device without a field plate. The bidirectional switching device includes a substrate 10, a channel layer 20, and a first source S1, a second source S2, a first gate G1, and a second gate G2 located on the channel layer 20 and symmetrically positioned at both ends; it also includes a dielectric layer 30 disposed on the channel layer 20 between the first gate G1 and the second gate G2.

[0053] S102. A left-right symmetrical inclined platform structure is formed in the middle region of the dielectric layer away from the channel layer.

[0054] S103. A first field plate and a second field plate are fabricated on the left and right sides of the inclined mezzanine structure, such that the first field plate and the second field plate respectively cover the exposed portions on the left and right sides of the mezzanine structure. The first field plate FP1 and the second field plate FP2 do not contact each other, and the first field plate FP1 and the second field plate FP2 are located in the region between the first gate G1 and the second gate G2.

[0055] In the middle region of the dielectric layer 30, a symmetrical inclined mesa structure 31 is fabricated. A first field plate FP1 and a second field plate FP2 are fabricated on both sides of the inclined mesa structure 31, which helps to further regulate the electric field, prevent the electric field from generating peaks at the edges of the field plates, improve the electric field distribution, and reduce electric field concentration. Due to the symmetry of the field plates and the design of the inclined mesa structure 31, the electric field distribution in the LG1G2 region (i.e., the region between the first gate G1 and the second gate G2) is more uniform.

[0056] Compared to related bidirectional switching devices, where the electric field between LG1 and G2 is still not uniform enough, the fabrication method of the bidirectional switching device provided in this embodiment simplifies the field plate structure, reduces the number of metal deposition and dielectric etching steps required for multi-layer field plates, thereby reducing manufacturing costs; the uniform distribution of the electric field helps to improve the breakdown voltage of the device, enhancing its performance and reliability; the simplified field plate structure reduces the space occupied by the device, which is beneficial for miniaturization design; the symmetry of G1 and G2 simplifies the process steps, making the production process easier to implement and improving production efficiency; the field plate design of the inclined mesa structure 31 helps to optimize the electric field distribution and reduce the occurrence of electric field peaks, thereby improving the electrical characteristics of the device; since it avoids the use of special processes such as grayscale exposure, this technical solution is more conducive to mass production and helps to reduce unit cost. In the region between the first gate G1 and the second gate G2, a symmetrical inclined mesa structure 31 is first fabricated. Then, field plates are fabricated on both sides of the inclined mesa structure 31. When a high voltage is applied to the first source S1, the corresponding first field plate FP1 plays a role in regulating the electric field; when a high voltage is applied to the second source S2, the corresponding second field plate FP2 plays a role in regulating the electric field. In summary, this method can improve the uniformity of the electric field between adjacent gates, thereby reducing the distance between them, lowering costs, and improving performance. In addition, the method utilizes the symmetry of the gates, simplifying the process steps and making it easy to implement. Compared with multilayer field plates, it can further reduce the manufacturing cost of the device, achieving the dual goals of cost-effectiveness and performance improvement.

[0057] See Figure 4 , Figure 4 This is a schematic diagram of the process for manufacturing an inclined platform structure 31, provided in an embodiment of this application.

[0058] In some embodiments, the step of creating a left-right symmetrical inclined platform structure 31 in the middle region of the dielectric layer 30 away from the channel layer 20 specifically includes S201 to S203.

[0059] S201. Photoresist is deposited on the dielectric layer, which is obtained by deposition on the channel layer.

[0060] S202. Heat the photoresist at a preset temperature so that the shape of the photoresist meets the preset pattern.

[0061] S203. Dry etching of the dielectric layer and photoresist to transfer the shape of the photoresist onto the dielectric layer.

[0062] The photoresist is heated to a preset temperature, giving it a certain degree of fluidity. Under the influence of surface tension, a smooth arc is formed on the photoresist surface, creating the desired preset pattern. Dry etching technology is then used to simultaneously etch the dielectric layer 30 and the photoresist. During etching, the photoresist acts as a mask, protecting the underlying dielectric layer 30 from etching, while the portion of the dielectric layer 30 not covered by the photoresist is etched away. In this way, the shape of the photoresist is transferred onto the dielectric layer 30, forming the desired tilted mesa structure 31.

[0063] Therefore, dry etching enables precise transfer of the photoresist pattern to the dielectric layer 30. Furthermore, compared to traditional multilayer field plate structures, this technology achieves the fabrication of the tilted mesa structure 31 through a single-step dry etching process, simplifying the manufacturing process. This simplified process reduces production steps and the need for specialized equipment and materials, thus helping to lower manufacturing costs. This technology allows for control over the specific shape of the tilted mesa structure 31 by adjusting parameters such as the width, thickness, reflow temperature, and time of the photoresist, providing greater flexibility for device design.

[0064] As an example, see Figures 5a to 5d . Figure 5a This is a schematic diagram of the deposition medium. Figure 5b This is a schematic diagram of a patterned photoresist (PR). Figure 5c This is a schematic diagram of the photoresist PR being heated and reflowed. Figure 5d This diagram illustrates the removal of photoresist (PR) and dielectric material using dry etching (with PR as a mask). In specific applications, the etching thickness can be selected to create different shapes.

[0065] Due to the symmetry of the first gate G1 and the second gate G2, a photoresist step is fabricated in the middle. Because the photoresist is fluid at a certain temperature (e.g., 150 degrees Celsius), a certain curvature will form on the surface under the action of surface tension. The morphology of the photoresist sidewalls is closely related to the width and thickness of the photoresist, and is also related to the reflow temperature and time. Given LG1G2 (the distance between the first gate G1 and the second gate G2), a photoresist of appropriate thickness can be selected, and the reflow adjustment can be controlled to ensure that the curvature meets the requirements. Then, dry etching is performed to transfer the photoresist pattern onto the dielectric, and finally, the photoresist is removed. Since the tilted mesa structure 31 exists only between the first gate G1 and the second gate G2, the dielectric above the metal electrodes (first gate G1, first source S1, second gate G2, and second source S2) can be effectively removed after the dielectric etching is completed, eliminating the need for thick dielectric etching, reducing process complexity, and saving costs. Due to the symmetry, the shapes of the first field plate FP1 and the second field plate FP2 are symmetrical, ensuring that the performance of the device is the same when the voltage is applied in both the forward and reverse directions. This helps to simplify the circuit design and improve the circuit performance.

[0066] In some embodiments, the etching rate ratio of the photoresist to the dielectric layer 30 is 1:X, where X is any one of 1, less than 1, or greater than 1, and the etching rate ratio is used to control the shape of the photoresist transferred onto the dielectric layer 30.

[0067] It can be assumed that when X = 1, the photoresist morphology is replicated; when X < 1, a vertically flattened morphology is formed; and when X > 1, a vertically stretched morphology is formed. Therefore, during the etching process, the etching conditions can be adjusted as needed to make X = X(t), so that X (etch selectivity) changes with time.

[0068] See Figures 6a to 6c , Figures 6a to 6c Schematic diagrams showing different morphologies of the inclined platform structure 31 provided in the embodiments of this application.

[0069] In some embodiments, the cross-sectional shape of the inclined mesa structure 31 is any one of an arc shape, a triangle, a trapezoid, or a trapezoid with arc sides. In this case, the shape of the preset pattern is any one of an arc shape, a triangle, a trapezoid, or a trapezoid with arc sides. The width, thickness, reflow temperature, and time of the photoresist can be controlled to control the sidewall morphology of the inclined mesa structure 31 of the dielectric layer 30.

[0070] In some embodiments, in step S1, the width of the photoresist is 1µm to 20µm, and the thickness of the photoresist is 0.2µm to 10µm; and / or,

[0071] In step S2, the preset temperature is 75℃~250℃, and the heating time is 30s~3h.

[0072] As an example, see Figures 7a to 7d This is a simplified flowchart illustrating the manufacturing process of a bidirectional switch provided in an embodiment of this application.

[0073] Figure 7a To define the active region, the source and gate are fabricated. Figure 7b To create the inclined platform structure 31, Figure 7c To make the production board, Figure 7d For the lead-out electrodes. Because the horizontal device has a periodic structure, in Figure 7b In the middle, the inclined platform structure 31 is a periodic strip structure. The side wall morphology at both ends will be different from that on both sides, which is not conducive to the fabrication of the field plate. Ion implantation method can be used to exclude the two ends from the active region.

[0074] Example 2

[0075] See Figure 3This embodiment provides a bidirectional switching device, which is obtained by using any of the bidirectional switching device preparation methods in Embodiment 1. The specific embodiment and the technical effects achieved are the same as those described in Embodiment 1 above, and some contents will not be repeated.

[0076] The bidirectional switching device includes a substrate 10 and a channel layer 20 arranged sequentially, and a first source S1, a second source S2 and a first gate G1 and a second gate G2 located on the channel layer 20 and symmetrically arranged at both ends.

[0077] It also includes a dielectric layer 30 disposed on the channel layer 20 between the first gate G1 and the second gate G2; the dielectric layer 30 includes an inclined mesa structure 31 in the middle region away from the channel layer 20, and also includes a first field plate FP1 and a second field plate FP2 on the left and right sides of the inclined mesa structure 31, such that the first field plate FP1 and the second field plate FP2 respectively cover the exposed portions on the left and right sides of the mesa structure, and the first field plate FP1 and the second field plate FP2 do not contact each other.

[0078] In some embodiments, the cross-sectional shape of the inclined platform structure 31 is any one of arc, triangle, trapezoid, or trapezoid with arc sides, and the inclined platform structure 31 is a left-right symmetrical structure.

[0079] In some embodiments, the first field plate FP1 and the second field plate FP2 are electrically connected to the first gate G1 and the second gate G2, respectively; or the first field plate FP1 and the second field plate FP2 are electrically connected to the first source S1 and the second source S2, respectively.

[0080] Example 3

[0081] This embodiment provides an electronic device, which includes the bidirectional switching device described in any one of Embodiment 2. The specific embodiments and technical effects achieved are consistent with those described in the above embodiments, and some details will not be repeated. The electronic device includes, for example, any one of a photovoltaic inverter, server power supply, motor drive, mobile phone, laptop computer, tablet computer, and wearable electronic device.

[0082] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A bidirectional switching device, comprising a substrate and a channel layer disposed sequentially, and a first source, a second source, a first gate, and a second gate located at both ends of the channel layer and symmetrically arranged left and right respectively; Its features are, It also includes a dielectric layer disposed on the channel layer between the first gate and the second gate; the dielectric layer includes an inclined mesa structure away from the middle region of the channel layer, and also includes a first field plate and a second field plate on the left and right sides of the inclined mesa structure, such that the first field plate and the second field plate respectively cover the exposed portions on the left and right sides of the mesa structure, and the first field plate and the second field plate do not contact each other.

2. The bidirectional switching device according to claim 1, characterized in that, The inclined platform structure is a symmetrical structure, and the cross-sectional shape of the inclined platform structure is any one of the following: arc, triangle, trapezoid, or trapezoid with arc sides.

3. The bidirectional switching device according to claim 11, characterized in that, The first field plate and the second field plate are electrically connected to the first gate and the second gate, respectively; or the first field plate and the second field plate are electrically connected to the first source and the second source, respectively.

4. A method for fabricating a bidirectional switching device, characterized in that, The method includes: S101. A bidirectional switching device without a field plate is provided. The bidirectional switching device includes a substrate, a channel layer, and a first source, a second source, a first gate, and a second gate located at both ends of the channel layer and symmetrically positioned to the left and right respectively; it also includes a dielectric layer disposed on the channel layer between the first gate and the second gate. S102. A left-right symmetrical inclined platform structure is formed in the middle region of the dielectric layer away from the channel layer; S103. A first field plate and a second field plate are made on the left and right sides of the inclined mezzanine structure, so that the first field plate and the second field plate respectively cover the exposed portions on the left and right sides of the mezzanine structure; wherein the first field plate and the second field plate do not contact each other, and the first field plate and the second field plate are in the region between the first gate and the second gate.

5. The method for fabricating a bidirectional switching device according to claim 4, characterized in that, The specific steps for fabricating a symmetrical inclined platform structure in the middle region of the dielectric layer away from the channel layer are as follows: S201. Photoresist is deposited on the dielectric layer, which is obtained by deposition on the channel layer; S202. Heat the photoresist at a preset temperature so that the shape of the photoresist meets the preset pattern; S203. Dry etching of the dielectric layer and photoresist to transfer the shape of the photoresist onto the dielectric layer.

6. The method for fabricating a bidirectional switching device according to claim 5, characterized in that, The etching rate ratio between the photoresist and the dielectric layer is 1:X, where X is any one of 1, less than 1, or greater than 1. The etching rate ratio is used to control the shape of the photoresist transferred onto the dielectric layer.

7. The method for fabricating a bidirectional switching device according to claim 6, characterized in that, The cross-sectional shape of the inclined platform structure can be any one of the following: arc, triangle, trapezoid, or trapezoid with arc sides.

8. The method for fabricating a bidirectional switching device according to claim 5, characterized in that, In step S1, the width of the photoresist is 1µm to 40µm, and the thickness of the photoresist is 0.2µm to 10µm; and / or, in step S2, the preset temperature is 75℃ to 250℃, and the heating time is 30s to 3h.

9. An electronic device, characterized in that, The electronic device includes a bidirectional switching device as described in any one of claims 1-3.

10. The electronic device according to claim 9, characterized in that, The electronic device includes any one of photovoltaic inverters, server power supplies, motor drives, mobile phones, laptops, tablets, and wearable electronic devices.

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