Integrated silicon carbide delta e-e telescope high energy particle detector and method of making

Abstract

This invention discloses an integrated silicon carbide ΔE-E telescope high-energy particle detector and its fabrication method. Using heavily doped p-type silicon carbide as a substrate, a p-type silicon carbide buffer layer and an L-shaped N-type silicon carbide epitaxial layer are fabricated on top of the substrate. A heavily doped N-type silicon carbide structure is placed on top of the L-shaped N-type silicon carbide epitaxial layer. A columnar heavily doped N-type silicon carbide structure connects to the top of the device around the L-shaped N-type silicon carbide structure. An N-type silicon carbide epitaxial layer is fabricated within the region enclosed by the heavily doped N-type silicon carbide structure and the columnar heavily doped N-type silicon carbide structure. A heavily doped p-type silicon carbide structure is placed on top of the N-type silicon carbide epitaxial layer. An upper electrode is placed on the heavily doped p-type silicon carbide, and lower electrodes are placed on the heavily doped p-type silicon carbide structure and the columnar heavily doped N-type silicon carbide structure, respectively. An insulating dielectric protective layer is filled between the two lower electrodes and outside one of the lower electrodes. The detector of this invention meets the requirements of radiation resistance, high temperature resistance, and miniaturization.

Description

Technical Field

[0001] This invention belongs to the field of semiconductor device fabrication technology, and relates to a novel integrated silicon carbide ΔE-E telescope high-energy particle detector with a PINIP structure and its fabrication method. Background Technology

[0002] With the development of nuclear science and technology, nuclear radiation detection technology plays an extremely important role in many fields such as medicine, environmental monitoring, space, and related interdisciplinary frontiers. Currently, particle detectors based on semiconductor materials such as silicon (Si) are relatively mature, but the narrow bandgap, small operating temperature range, and weak radiation resistance of Si materials limit the overall performance of the detectors. To improve detector performance, research on detectors based on third-generation semiconductor materials such as silicon carbide has been deepening in recent years.

[0003] There are several main methods for achieving high-energy particle detection, one of which is using ΔE-E structures. There are already some examples of integrated ΔE-E telescope detectors developed to meet miniaturization needs, such as the silicon-based integrated telescope developed by A. Topkar et al. and the monolithic ΔE-E diamond telescope by C. Verona et al. However, the fabrication of these detectors is still mainly based on materials such as diamond and silicon, and research using silicon carbide is very lacking. Summary of the Invention

[0004] In order to optimize the existing ΔE-E telescope detectors based on materials such as Si and diamond, and to meet the requirements for high-energy particle detection, the present invention aims to propose an integrated silicon carbide ΔE-E telescope high-energy particle detector and its fabrication method, which meets the requirements of radiation resistance, high temperature resistance, and miniaturization, and realizes the development of a novel integrated silicon carbide ΔE-E telescope high-energy particle detector.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: An integrated silicon carbide ΔE-E telescope high-energy particle detector includes a heavily doped p-type silicon carbide substrate 1, a p-type silicon carbide buffer layer 2 disposed above the heavily doped p-type silicon carbide substrate 1, and an L-shaped N-type silicon carbide epitaxial layer 3 disposed above the p-type silicon carbide buffer layer 2; a heavily doped N-type silicon carbide structure 4 disposed on top of the L-shaped N-type silicon carbide epitaxial layer 3; a columnar heavily doped N-type silicon carbide structure 5 disposed above the heavily doped N-type silicon carbide structure 4 and in contact with the L-shaped N-type silicon carbide layer 3 and connected to the top of the device; an N-type silicon carbide epitaxial layer 6 disposed within the area enclosed by the heavily doped N-type silicon carbide structure 4 and the columnar heavily doped N-type silicon carbide structure 5; and a heavily doped p-type silicon carbide structure 7 disposed on top of the N-type silicon carbide epitaxial layer 6. An upper electrode 9 is disposed at the bottom of the heavily doped P-type silicon carbide substrate 1, a first lower electrode 10 is disposed on the heavily doped P-type silicon carbide structure 7, and a second lower electrode 11 is disposed on the columnar heavily doped N-type silicon carbide structure 5. An insulating dielectric protective layer 8 is filled between each of the first lower electrode 10 and the second lower electrode 11 and on the outside of the second lower electrode 11.

[0006] The insulating dielectric protective layer 8 is made of gallium oxide, silicon dioxide, aluminum nitride, or silicon nitride. These materials can protect the device from normal operation in relatively high temperature and strong radiation environments while reducing the leakage current on the device surface. The thickness of the insulating dielectric protective layer 8 is 10 nm to 1 μm. At this thickness, the possibility of device breakdown is reduced while the fabrication of metal openings is made easier.

[0007] The thickness of the heavily doped N-type silicon carbide structure 4 is 10 nm to 100 μm; the height of the columnar heavily doped N-type silicon carbide structure 5 is 100 nm to 100 μm; and the thickness of the heavily doped P-type silicon carbide structure 7 is 10 nm to 100 μm. The above thicknesses are conducive to achieving efficient ohmic contacts while ensuring that the depletion region width is sufficiently wide.

[0008] The thickness of the detection sensitive region of the L-shaped N-type silicon carbide epitaxial layer 3 is 10 nm to 500 μm; the thickness of the detection sensitive region of the N-type silicon carbide epitaxial layer 6 is 10 nm to 500 μm. The above thickness is beneficial for detecting particles with higher energy while avoiding excessive local electric field intensity within the device.

[0009] The fabrication method of the integrated silicon carbide ΔE-E telescope high-energy particle detector includes the following steps: Step 1: Prepare the P-type silicon carbide buffer layer 2 on the silicon surface of the heavily doped P-type silicon carbide substrate 1; Step 2: Prepare the N-type silicon carbide epitaxial layer on top of the P-type silicon carbide buffer layer 2; Step 3: On the top of the N-type silicon carbide epitaxial layer, nitrides and oxides are deposited according to a preset pattern using photolithography masking technology to form a protective layer that blocks particle injection; Step 4: Phosphorus or nitrogen ions are implanted on the top of the N-type silicon carbide epitaxial layer and activated to form the heavily doped N-type silicon carbide structure 4. Then, the protective layer that blocks particle implantation is removed by hydrofluoric acid wet etching technology. Step 5: After processing in step 4, the columnar heavily doped N-type silicon carbide structure 5 and the N-type silicon carbide epitaxial layer 6 are prepared on the heavily doped N-type silicon carbide structure 4. At the same time, the N-type silicon carbide epitaxial layer is prepared as an L-shaped N-type silicon carbide epitaxial layer 3. Step 6: On the top of the N-type silicon carbide epitaxial layer 6, nitrides and oxides are deposited according to a preset pattern using photolithography masking technology to form a protective layer that blocks particle injection. Step 7: Aluminum or boron ions are implanted on top of the N-type silicon carbide epitaxial layer 6 and activated to form the heavily doped P-type silicon carbide structure 7. Then, the protective layer that blocks particle implantation is removed by hydrofluoric acid wet etching technology. Step 8: Activate all dopants after the treatment in step 7; Step 9: Prepare an insulating dielectric protective layer on the surface of the columnar heavily doped N-type silicon carbide structure 5, the N-type silicon carbide epitaxial layer 6, and the heavily doped P-type silicon carbide structure 7 after the treatment in Step 5; then open electrode holes on the surface of the columnar heavily doped N-type silicon carbide structure 5 and the heavily doped P-type silicon carbide structure 7. Step 10: Prepare an upper electrode 9 at the bottom of the heavily doped P-type silicon carbide substrate 1, prepare a first lower electrode 10 in the electrode opening region on the surface of the heavily doped P-type silicon carbide structure 7, and prepare a second lower electrode in the electrode opening region on the surface of the columnar heavily doped N-type silicon carbide structure 5.

[0010] In step 5, the columnar heavily doped N-type silicon carbide structure 5 and the N-type silicon carbide outer layer 6 are prepared using a cyclic process, the steps of which include: Step 3.1: Prepare an N-type silicon carbide epitaxial layer 6 on top of the heavily doped N-type silicon carbide structure 4; Step 3.2: On the top of the N-type silicon carbide epitaxial layer 6 after the treatment in step 3.1, nitrides and oxides are deposited according to a preset pattern using photolithography mask technology to form a protective layer that blocks particle implantation. The above treatment can ensure that ions are implanted in the designated area while protecting other areas that do not want to be implanted. Step 3.3: Phosphorus or nitrogen ions are implanted into the top of the N-type silicon carbide epitaxial layer 6 after the treatment in step 3.1 and activated to prepare the columnar heavily doped N-type silicon carbide structure 5, so that it is connected to the heavily doped N-type silicon carbide structure 4. Then, the protective layer that blocks particle implantation is removed by hydrofluoric acid wet etching technology. The above treatment can enable the heavily doped N-type silicon carbide structure 5 and the heavily doped N-type silicon carbide structure 4 to jointly control the electric field in the device through the electrodes made in step 10. Step 3.4: Repeat steps 3.1 and 3.3 until the thickness and height of the columnar heavily doped N-type silicon carbide structure 5 and the N-type silicon carbide layer 6 meet the requirements.

[0011] In step 1, the P-type silicon carbide buffer layer 2 is epitaxially grown on the silicon surface of the heavily doped P-type silicon carbide substrate 1 using epitaxial growth technology. The above structure can ensure that there is no local high electric field region at the interface between the heavily doped P-type silicon carbide substrate 1 and the N-type silicon carbide epitaxial layer 3.

[0012] In step 9, an insulating dielectric protective layer is deposited and grown on the surfaces of the columnar heavily doped N-type silicon carbide structure 5, the N-type silicon carbide layer 6, and the heavily doped P-type silicon carbide structure 7 after the treatment in step 5. The above structure can protect the device from normal operation in a relatively high temperature and strong radiation environment while reducing the leakage current on the device surface.

[0013] In step 9, an opening region is prepared on the surface of the columnar heavily doped N-type silicon carbide structure 5 and the heavily doped P-type silicon carbide structure 7 using photolithography mask and inductively coupled plasma etching technology; in step 10, a second lower electrode 11 and a first lower electrode 10 are prepared in the opening region using electron beam deposition technology. The above process can prepare the electrode structure with relatively high precision.

[0014] The present invention has the following advantages: 1. Because the underlying N-type silicon carbide epitaxial layer is L-shaped, the detection angle of the detector can be further extended, giving it the advantage of a wide detection angle; 2. Due to the relatively wide epitaxial layer thickness, the particle detection energy range is widened while the breakdown voltage of the device is improved; 3. Due to the buffer layer structure, the interface between the heavily doped substrate and the epitaxial layer is prevented from having local high electric field regions; 4. Due to the insulating dielectric protective layer, the device can be protected from operation in high temperature and strong radiation environments; 5. Due to the use of photolithography mask technology, the ion implantation process can occur within the designated area to avoid contamination of other areas; 6. Due to the use of a cyclic manufacturing process, the columnar heavily doped N-type silicon carbide structure in the device is fabricated; 7. Due to the use of photolithography mask, inductively coupled plasma etching technology, and electron beam deposition technology, the electrode structure can be fabricated with greater precision.

[0015] The innovation of this invention lies in the design of a novel particle detector structure based on silicon carbide material and the proposal of an effective manufacturing process. Through this invention, miniaturized particle detectors suitable for high temperature and high radiation environments can be fabricated, realizing the development of a novel integrated silicon carbide ΔE-E telescope particle detector. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of a novel integrated silicon carbide ΔE-E telescope particle detector.

[0017] Figure 2 A flowchart illustrating the fabrication process of a novel integrated silicon carbide ΔE-E telescope particle detector; Figure 3 This is a flow chart of a cyclic process method; Figure 4 The device model is obtained by simulating the above process flow using the SPROCESS module of Sentaurus TCAD. Detailed Implementation

[0018] The present invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0019] The structure of the integrated silicon carbide ΔE-E telescope high-energy particle detector device of this invention is as follows: Figure 1 As shown, it includes a heavily doped P-type silicon carbide substrate 1, a P-type silicon carbide buffer layer 2, an L-shaped N-type silicon carbide epitaxial layer 3, a heavily doped N-type silicon carbide structure 4, a columnar heavily doped N-type silicon carbide structure 5, an N-type silicon carbide epitaxial layer 6, a heavily doped P-type silicon carbide structure 7, an insulating dielectric protective layer 8, a lower electrode 9, a first upper electrode 10, and a second upper electrode 11; The detector uses heavily doped p-type silicon carbide 1 as a substrate. First, a p-type silicon carbide buffer layer 2 is epitaxially grown on the silicon surface of the heavily doped p-type silicon carbide 1. Then, an n-type silicon carbide layer 3 is epitaxially grown on top of the p-type silicon carbide buffer layer 2. On top of the n-type silicon carbide layer 3, patterned nitrides and oxides are deposited using photolithography and hydrofluoric acid wet etching to form a protective layer that blocks particle implantation. Then, phosphorus or nitrogen ions are implanted and activated on top of the n-type silicon carbide layer 3 to form a heavily doped n-type silicon carbide structure 4. Afterward, the protective layer blocking particle implantation is removed using hydrofluoric acid wet etching. A columnar heavily doped n-type silicon carbide structure 5 and an n-type silicon carbide layer 6 are fabricated on the treated n-type silicon carbide layer 3 and the heavily doped n-type silicon carbide structure 4 using a cyclic process. Finally, a columnar heavily doped n-type silicon carbide structure 5 and an n-type silicon carbide layer 6 are fabricated on top of the n-type silicon carbide layer 6. Patterned nitrides and oxides are deposited using photolithography and hydrofluoric acid wet etching to form a protective layer that blocks particle implantation. Then, aluminum or boron ions are implanted onto the top of the N-type silicon carbide layer 6 and activated to form a heavily doped P-type silicon carbide structure 7. The protective layer blocking particle implantation is then removed using hydrofluoric acid wet etching. All dopants in the device are activated. An insulating dielectric protective layer is deposited on the surfaces of the treated columnar heavily doped N-type silicon carbide structure 5, N-type silicon carbide layer 6, and heavily doped P-type silicon carbide structure 7. Electrode holes are then opened on the surfaces of the columnar heavily doped N-type silicon carbide structure 5 and the heavily doped P-type silicon carbide structure 7 using photolithography and hydrofluoric acid wet etching. A top electrode 9 is fabricated at the bottom of the heavily doped P-type silicon carbide substrate 1. A second bottom electrode 11 is fabricated in the electrode opening area on the surface of the columnar heavily doped N-type silicon carbide structure 5. A first bottom electrode 10 is fabricated in the electrode opening area on the surface of the heavily doped P-type silicon carbide structure 7. The thicknesses of the N-type silicon carbide layer 3 and the N-type silicon carbide layer 6 are customized according to the actual detection requirements.

[0020] The insulating dielectric protective layer material can be gallium oxide, silicon dioxide, aluminum nitride, or silicon nitride, and its thickness is 10 nm to 1 μm.

[0021] The thickness of the heavily doped N-type silicon carbide structure 4 is 10 nm to 100 μm.

[0022] The height of the columnar heavily doped N-type silicon carbide structure 5 is 100 nm to 100 μm.

[0023] The thickness of the heavily doped p-type silicon carbide structure 7 is 10 nm to 100 μm.

[0024] The thickness of the detection sensitive region of the L-shaped N-type silicon carbide epitaxial layer 3 is 10 nm to 500 μm.

[0025] The thickness of the detection sensitive region of the N-type silicon carbide epitaxial layer 6 is 10 nm to 500 μm.

[0026] The method for fabricating the integrated silicon carbide ΔE-E telescope high-energy particle detector of the present invention includes the following steps: Step 1: Clean the surface of the heavily doped P-type silicon carbide substrate 1, and generate P-type silicon carbide 2 with a thickness of 1 μm on its silicon surface by epitaxy; Step 2: An N-type silicon carbide layer 3 with a thickness of 80 μm is grown on top of the P-type silicon carbide buffer layer 2 prepared in step 1 by epitaxy. Step 3: Deposit 100nm silicon dioxide and 1μm silicon nitride on top of the N-type silicon carbide layer 3 prepared in step 2, use photoresist to create a patterned mask, and then use hydrofluoric acid to perform anisotropic wet etching to form a protective layer that blocks particle injection, and remove the photoresist. Step 4: Nitrogen ions are implanted multiple times on the top of the N-type silicon carbide layer 3 prepared in step 3 and activated to form a 2μm heavily doped N-type silicon carbide structure 4. Then, anisotropic wet etching is performed using hydrofluoric acid to remove the protective layer that blocks particle implantation. Step 5: On the N-type silicon carbide layer 3 and the heavily doped N-type silicon carbide structure 4 prepared in step 4, a columnar heavily doped N-type silicon carbide structure 5 with a height of 6 μm and an N-type silicon carbide layer 6 with a thickness of 6 μm are prepared using a set of cyclic processes. Step 6: Deposit 100nm silicon dioxide and 1μm silicon nitride on top of the N-type silicon carbide layer 6 prepared in step 5, use photoresist to create a patterned mask, and then use hydrofluoric acid to perform anisotropic wet etching to form a protective layer that blocks particle injection, and remove the photoresist. Step 7: Aluminum ions are implanted multiple times on the top of the N-type silicon carbide layer 6 prepared in step 6 and activated to form a 1μm heavily doped P-type silicon carbide structure 7. Then, anisotropic wet etching is performed using hydrofluoric acid to remove the protective layer that blocks particle implantation. Step 8: Activate all dopants in the device through an annealing process; Step 9: On the device surface prepared in step 7, 50nm silicon dioxide is deposited and grown as a device protective layer. A patterned mask is made using photoresist. Then, anisotropic wet etching is performed using hydrofluoric acid to create electrode holes on the surfaces of the columnar heavily doped N-type silicon carbide structure 5 and the heavily doped P-type silicon carbide structure 7. The photoresist is then removed. Step 10: Using photolithography, inductively coupled plasma etching, and electron beam deposition, a corresponding ohmic contact upper electrode 9 is fabricated on the bottom of the heavily doped P-type silicon carbide substrate 1. An ohmic contact second lower electrode 11 is fabricated in the electrode opening region on the surface of the columnar heavily doped N-type silicon carbide structure 5. An ohmic contact first lower electrode 10 is fabricated in the electrode opening region on the surface of the heavily doped P-type silicon carbide structure 7.

[0027] In step 5, the columnar heavily doped N-type silicon carbide structure 5 and the N-type silicon carbide outer layer 6 are prepared using a cyclic process, the steps of which include: Step 1: An N-type silicon carbide layer of 600 nm is grown epitaxially on top of the N-type silicon carbide layer 3 and the heavily doped N-type silicon carbide structure 4. Step 2: Deposit 100nm silicon dioxide and 1μm silicon nitride on top of the N-type silicon carbide layer prepared in step 1, use photoresist to create a patterned mask, and then use hydrofluoric acid to perform anisotropic wet etching to form a protective layer that blocks particle injection, and remove the photoresist. Step 3: Nitrogen ions are implanted multiple times on the top of the N-type silicon carbide layer prepared in step 2 and activated to form a 600nm columnar heavily doped N-type silicon carbide structure 5. Then, anisotropic wet etching is performed using hydrofluoric acid to remove the protective layer that blocks particle implantation. Step 4: Repeat steps 1 to 3 a total of 10 times until the thickness and height of the columnar heavily doped N-type silicon carbide structure 5 and the N-type silicon carbide layer 6 reach 6 μm.

[0028] The device model obtained by simulating the process flow of Example 1 using the SPROCESS module of Sentaurus TCAD is as follows: Figure 4 As shown in the figure, the complete ΔE-E structure was successfully integrated into the same structure through the above process route, and a high-energy particle detector for the ΔE-E telescope made of silicon carbide with high temperature resistance and radiation resistance was prepared.

[0029] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An integrated silicon carbide ΔE-E telescope high-energy particle detector, characterized by: The device includes a heavily doped P-type silicon carbide substrate (1), a P-type silicon carbide buffer layer (2) disposed above the heavily doped P-type silicon carbide substrate (1), and an L-shaped N-type silicon carbide epitaxial layer (3) disposed above the P-type silicon carbide buffer layer (2); a heavily doped N-type silicon carbide structure (4) disposed on top of the L-shaped N-type silicon carbide epitaxial layer (3); a columnar heavily doped N-type silicon carbide structure (5) that contacts the L-shaped N-type silicon carbide layer (3) and is connected to the top of the device is disposed above the heavily doped N-type silicon carbide structure (4); an N-type silicon carbide epitaxial layer (6) is disposed in the area surrounded by the heavily doped N-type silicon carbide structure (4) and the columnar heavily doped N-type silicon carbide structure (5); and a heavily doped P-type silicon carbide structure (7) is disposed on top of the N-type silicon carbide epitaxial layer (6). An upper electrode (9) is provided at the bottom of the heavily doped P-type silicon carbide substrate (1), a first lower electrode (10) is provided on the heavily doped P-type silicon carbide structure (7), and a second lower electrode (11) is provided on the columnar heavily doped N-type silicon carbide structure (5). An insulating dielectric protective layer (8) is filled between each of the first lower electrode (10) and the second lower electrode (11) and outside the second lower electrode (11).

2. The integrated silicon carbide ΔE-E telescope high-energy particle detector of claim 1, wherein, The insulating dielectric protective layer (8) is made of gallium oxide, silicon dioxide, aluminum nitride or silicon nitride, and has a thickness of 10 nm to 1 μm.

3. The integrated silicon carbide ΔE-E telescope high-energy particle detector of claim 1, wherein, The thickness of the heavily doped N-type silicon carbide structure (4) is 10 nm to 100 μm; the height of the columnar heavily doped N-type silicon carbide structure (5) is 100 nm to 100 μm; and the thickness of the heavily doped P-type silicon carbide structure (7) is 10 nm to 100 μm.

4. The integrated silicon carbide ΔE-E telescope high-energy particle detector of claim 1, wherein, The thickness of the detection sensitive area of ​​the L-shaped N-type silicon carbide epitaxial layer (3) is 10 nm to 500 μm; the thickness of the detection sensitive area of ​​the N-type silicon carbide epitaxial layer (6) is 10 nm to 500 μm.

5. A method of fabricating an integrated silicon carbide ΔE-E telescope high-energy particle detector according to any one of claims 1 to 4, characterized in that: Includes the following steps: Step 1: Prepare the P-type silicon carbide buffer layer (2) on the silicon surface of the heavily doped P-type silicon carbide substrate (1); Step 2: Prepare the N-type silicon carbide epitaxial layer on top of the P-type silicon carbide buffer layer (2); Step 3: On the top of the N-type silicon carbide epitaxial layer, nitrides and oxides are deposited according to a preset pattern using photolithography masking technology to form a protective layer that blocks particle injection; Step 4: Phosphorus or nitrogen ions are implanted on the top of the N-type silicon carbide epitaxial layer and activated to form the heavily doped N-type silicon carbide structure (4). Then, the protective layer that blocks particle implantation is removed by hydrofluoric acid wet etching technology. Step 5: Prepare the columnar heavily doped N-type silicon carbide structure (5) and the N-type silicon carbide epitaxial layer (6) on the heavily doped N-type silicon carbide structure (4) after the treatment in step 4. At the same time, prepare the N-type silicon carbide epitaxial layer as an L-shaped N-type silicon carbide epitaxial layer (3). Step 6: On the top of the N-type silicon carbide epitaxial layer (6), nitrides and oxides are deposited according to a preset pattern using photolithography masking technology to form a protective layer that blocks particle injection; Step 7: Aluminum or boron ions are implanted on the top of the N-type silicon carbide epitaxial layer (6) and activated to form the heavily doped P-type silicon carbide structure (7). Then, the protective layer that blocks particle implantation is removed by hydrofluoric acid wet etching technology. Step 8: Activate all dopants after the treatment in step 7; Step 9: Prepare an insulating dielectric protective layer on the surface of the columnar heavily doped N-type silicon carbide structure (5), the N-type silicon carbide epitaxial layer (6), and the heavily doped P-type silicon carbide structure (7) after the treatment in step 5; Then, electrode holes are opened on the surfaces of the columnar heavily doped N-type silicon carbide structure (5) and the heavily doped P-type silicon carbide structure (7); Step 10: Prepare an upper electrode (9) at the bottom of the heavily doped P-type silicon carbide substrate (1), prepare a first lower electrode (10) in the electrode opening region on the surface of the heavily doped P-type silicon carbide structure (7), and prepare a second lower electrode in the electrode opening region on the surface of the columnar heavily doped N-type silicon carbide structure (5).

6. The preparation method according to claim 5, characterized in that, In step 5, the columnar heavily doped N-type silicon carbide structure (5) and the N-type silicon carbide outer layer (6) are prepared using a cyclic process, the steps of which include: Step 3.1: Prepare an N-type silicon carbide epitaxial layer (6) on top of the heavily doped N-type silicon carbide structure (4); Step 3.2: On the top of the N-type silicon carbide epitaxial layer (6) after step 3.1, nitrides and oxides are deposited according to a preset pattern using photolithography masking technology to form a protective layer that blocks particle injection; Step 3.3: Phosphorus or nitrogen ions are injected into the top of the N-type silicon carbide epitaxial layer (6) after the treatment in step 3.1 and activated to prepare the columnar heavily doped N-type silicon carbide structure (5), so that it is connected to the heavily doped N-type silicon carbide structure (4), and then the protective layer that blocks particle injection is removed by hydrofluoric acid wet etching technology. Step 3.4: Repeat steps 3.1 and 3.3 until the thickness and height of the columnar heavily doped N-type silicon carbide structure (5) and the N-type silicon carbide layer (6) meet the requirements.

7. The preparation method according to claim 5, characterized in that, In step 1, the P-type silicon carbide buffer layer (2) is epitaxially grown on the silicon surface of the heavily doped P-type silicon carbide substrate (1) using epitaxial growth technology; in step 2, the N-type silicon carbide epitaxial layer (3) is epitaxially grown on top of the P-type silicon carbide buffer layer (2) using epitaxial growth technology.

8. The preparation method according to claim 5, characterized in that, In step 9, an insulating dielectric protective layer is deposited and grown on the surfaces of the columnar heavily doped N-type silicon carbide structure (5), the N-type silicon carbide layer (6), and the heavily doped P-type silicon carbide structure (7) after the treatment in step 5.

9. The preparation method according to claim 5, characterized in that, In step 9, electrode opening regions are prepared on the surfaces of the columnar heavily doped N-type silicon carbide structure (5) and the heavily doped P-type silicon carbide structure (7) using photolithography mask and inductively coupled plasma etching technology; in step 10, a second lower electrode (11) and a first lower electrode (10) are prepared in the opening regions using electron beam deposition technology.

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