SiC / Ga2O3 heterojunction single-photon ultraviolet detector and its preparation method

Abstract

The present invention discloses a SiC / Ga2O3 heterojunction single-photon ultraviolet detector and a method for fabricating the same. The method comprises: preparing a device functional layer and etching to form a mesa structure with an angle; depositing a first passivation layer on the upper surface of the mesa structure; etching the first passivation layer and an n+-type Ga2O3 epitaxial layer to form a photosensitive window; depositing Ni / Au metal on the upper and lower surfaces of the device, performing ohmic contact self-alignment, and then performing ohmic contact transparency treatment to form an anode transparent ohmic contact within each photosensitive window and a cathode transparent ohmic contact on the lower surface of the device; forming an anode metal electrode on the upper surface of the anode transparent ohmic contact located on the sidewall of each photosensitive window; forming a second passivation layer on the upper surface of the anode transparent ohmic contact within each photosensitive window, and forming a cathode metal electrode on the lower surface of the cathode transparent ohmic contact. The present invention solves the problem of poor device performance caused by using a single SiC material to fabricate single-photon ultraviolet detectors.

Description

Technical Field

[0001] The present invention belongs to the technical field of semiconductor optoelectronic devices, and in particular relates to a SiC / Ga2O3 heterojunction single-photon ultraviolet detector and a preparation method thereof. Background Art

[0002] Ultraviolet single-photon detectors have broad application prospects in quantum communication, quantum computing, laser radar (LiDAR), biological imaging and other fields. They often operate in Geiger mode, which requires applying a bias voltage exceeding the breakdown voltage (usually the excess voltage is 1 to 5V). Therefore, the materials selected for preparing ultraviolet single-photon detectors need to have a high critical breakdown field strength to achieve the working goal.

[0003] Silicon carbide, as an excellent representative of the third-generation semiconductor materials, can be used to prepare ultraviolet single-photon detectors. However, the existing technology only uses a single silicon carbide material as the light absorption layer during preparation. Single silicon carbide material is an indirect bandgap semiconductor material, which is not conducive to achieving good photoelectric detection performance. Summary of the Invention

[0004] In order to solve the above problems existing in the prior art, the present invention provides a SiC / Ga2O3 heterojunction single-photon ultraviolet detector and a method for preparing the same. The technical problem to be solved by the present invention is achieved through the following technical solutions:

[0005] In a first aspect, the present invention provides a method for preparing a SiC / Ga2O3 heterojunction single-photon ultraviolet detector, comprising:

[0006] A device functional layer is prepared and a mesa structure with an inclination angle is formed by etching; the device functional layer includes, from bottom to top, a P+ type SiC substrate, a P+ type SiC epitaxial layer, an n- type Ga2O3 epitaxial layer and an n+ type Ga2O3 epitaxial layer;

[0007] depositing a first passivation layer on the upper surface of the mesa structure;

[0008] Etching the first passivation layer and the n+ type Ga2O3 epitaxial layer to form a plurality of photosensitive windows;

[0009] After depositing Ni / Au metal on the upper and lower surfaces of the device, respectively, a rapid thermal annealing process is used to perform ohmic contact self-alignment, followed by a chemistries to perform ohmic contact transparency treatment, forming anode transparent ohmic contacts in each of the photosensitive windows and cathode transparent ohmic contacts on the lower surface of the device. Simultaneously, residual metal on the first passivation layer is washed away, and the annealed first passivation layer is reflowed to form a moth-eye array.

[0010] forming an anode metal electrode on the upper surface of the anode transparent ohmic contact located on the side wall of each photosensitive window;

[0011] A second passivation layer is formed on the upper surface of the anode transparent ohmic contact in each photosensitive window, and a cathode metal electrode is formed on the lower surface of the cathode transparent ohmic contact to obtain a prepared SiC / Ga2O3 heterojunction single-photon ultraviolet detector.

[0012] In one embodiment of the present invention, the step of preparing a device functional layer and forming a mesa structure with an inclination angle by etching includes:

[0013] Providing a P+ type SiC substrate;

[0014] sequentially growing a P+ type SiC epitaxial layer, an n- type Ga2O3 epitaxial layer and an n+ type Ga2O3 epitaxial layer on one side surface of the P+ type SiC substrate to form a device functional layer;

[0015] The p+ type SiC epitaxial layer, the n- type Ga2O3 epitaxial layer and the n+ type Ga2O3 epitaxial layer are etched to form a mesa structure with an inclination angle of 70° to 80°.

[0016] In one embodiment of the present invention, the thickness of the P+ type SiC substrate is 350 μm and the doping concentration is 5×10 18 cm -3 The thickness of the P+ type SiC epitaxial layer is 1 to 2 μm, and the doping concentration is 5×10 16 ~1×10 17 cm -3 The thickness of the n-type Ga2O3 epitaxial layer is 8 to 10 μm, and the doping concentration is 5×10 15 ~8×10 15 cm -3 The thickness of the n+ type Ga2O3 epitaxial layer is 0.8 to 1 μm, and the doping concentration is 1×10 18 ~5×10 18 cm -3 .

[0017] In one embodiment of the present invention, the bottom of each photosensitive window is 100 nm away from the lower surface of the n+ type Ga2O3 epitaxial layer, the width of each photosensitive window is 500 to 800 nm, and the interval between two adjacent photosensitive windows is 500 to 800 nm.

[0018] In one embodiment of the present invention, the material of the first passivation layer includes alkaline earth doped silicon oxide.

[0019] In one embodiment of the present invention, after depositing Ni / Au metal on the upper and lower surfaces of the device, respectively, a rapid thermal annealing process is used to perform ohmic contact self-alignment, followed by a chemistries to perform ohmic contact transparency treatment, forming an anode transparent ohmic contact in each of the photosensitive windows and a cathode transparent ohmic contact on the lower surface of the device, while simultaneously washing away residual metal on the first passivation layer and reflowing the annealed first passivation layer to form a moth-eye array, the steps include:

[0020] Using electron beam evaporation or magnetron sputtering, Ni / Au metal is deposited on the upper and lower surfaces of the device respectively, and ohmic contact self-alignment is performed using rapid thermal annealing process;

[0021] The annealed device is subjected to ohmic contact transparency treatment using a liquid chemical, forming an anode transparent ohmic contact in each of the photosensitive windows and a cathode transparent ohmic contact on the lower surface of the device, and washing away the Ni / Au metal remaining on the surface of the first passivation layer, so that the first passivation layer that has undergone the annealing reaction reflows to form a moth-eye array; the liquid chemical comprises nitric acid, buffered oxide etchant BOE, and deionized water in a volume ratio of 1:1:5.

[0022] In one embodiment of the present invention, the step of forming an anode metal electrode on the upper surface of the anode transparent ohmic contact located on the side wall of each photosensitive window includes:

[0023] Depositing Al metal with a thickness of 500 to 1000 nm on the upper surface of the device,

[0024] Through etching and corrosion processes, an anode metal electrode is formed on the upper surface of the anode transparent ohmic contact located on the side wall of each photosensitive window.

[0025] In one embodiment of the present invention, the material of the second passivation layer includes Si y N x , x and y represent the components of N and Si respectively, wherein x is 1 to 3 and y is 2 to 4.

[0026] In one embodiment of the present invention, the step of forming a cathode metal electrode on the lower surface of the cathode transparent ohmic contact comprises:

[0027] Ti / Ni / Ag metals with thicknesses of 200nm / 200nm / 1000nm were deposited on the lower surface of the cathode transparent ohmic contact by using an electron beam evaporation process to form a cathode metal electrode.

[0028] In a second aspect, the present invention further provides a SiC / Ga2O3 heterojunction single-photon ultraviolet detector, which is prepared using the preparation method of the SiC / Ga2O3 heterojunction single-photon ultraviolet detector as described in the first aspect.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] (1) The prior art uses only a single silicon carbide material as the light absorption layer during preparation. A single material has only one characteristic response peak. The present invention introduces gallium oxide during the preparation of a single-photon ultraviolet detector, which can broaden the wavelength range of the device and solve the problem of poor device performance caused by using a single SiC to prepare a single-photon ultraviolet detector. At the same time, it simplifies the preparation process without adding additional optical management processes.

[0031] (2) The material of the first passivation layer in the present invention includes alkaline earth doped silicon oxide. Therefore, after annealing, the first passivation layer can be reflowed into a moth-eye array, thereby obtaining light anti-reflection and anti-transmittance capability, which is beneficial to improving the photoelectric detection performance of the single-photon ultraviolet detector.

[0032] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 This is a flow chart of a method for preparing a SiC / Ga2O3 heterojunction single-photon ultraviolet detector provided by an embodiment of the present invention;

[0034] Figures 2 to 10 This is a schematic diagram of the preparation process of another SiC / Ga2O3 heterojunction single-photon ultraviolet detector provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0035] The present invention will be further described in detail below with reference to specific examples, but the embodiments of the present invention are not limited thereto.

[0036] Figure 1 This is a flow chart of a method for preparing a SiC / Ga2O3 heterojunction single-photon ultraviolet detector provided by an embodiment of the present invention. Figures 2 to 10 This is a schematic diagram of the preparation process of another SiC / Ga2O3 heterojunction single-photon ultraviolet detector provided by an embodiment of the present invention. Figures 1 to 10 The embodiment of the present invention provides a method for preparing a SiC / Ga2O3 heterojunction single-photon ultraviolet detector, comprising:

[0037] S1. Prepare a device functional layer 1 and form a mesa structure 2 with an inclination angle by etching; the device functional layer 1 includes, from bottom to top, a P+ type SiC substrate 101, a P+ type SiC epitaxial layer 102, an n- type Ga2O3 epitaxial layer 103, and an n+ type Ga2O3 epitaxial layer 104;

[0038] S2, depositing a first passivation layer 3 on the upper surface of the mesa structure 2;

[0039] S3, etching the first passivation layer 3 and the n+ type Ga2O3 epitaxial layer 104 to form a plurality of photosensitive windows 4;

[0040] S4. After depositing Ni / Au metal 5 on the upper and lower surfaces of the device, ohmic contacts are self-aligned using a rapid thermal annealing process. Then, the ohmic contacts are transparentized using a solution to form anode transparent ohmic contacts 6 in each photosensitive window 4 and cathode transparent ohmic contacts 7 on the lower surface of the device. At the same time, the residual metal on the first passivation layer 3 is washed away, and the annealed first passivation layer 3 is reflowed to form a moth-eye array.

[0041] S5, forming an anode metal electrode 8 on the upper surface of the anode transparent ohmic contact 6 located on the side wall of each photosensitive window 4;

[0042] S6. Form a second passivation layer 9 on the upper surface of the anode transparent ohmic contact 6 in each photosensitive window 4, and form a cathode metal electrode 10 on the lower surface of the cathode transparent ohmic contact 7 to obtain a completed SiC / Ga2O3 heterojunction single-photon ultraviolet detector.

[0043] like Figures 2-3 As shown, in step S1, the step of preparing the device functional layer 1 and forming the mesa structure 2 with an inclination angle by etching includes:

[0044] S101, providing a P+ type SiC substrate 101;

[0045] S102, sequentially growing a P+ type SiC epitaxial layer 102, an n- type Ga2O3 epitaxial layer 103 and an n+ type Ga2O3 epitaxial layer 104 on one side surface of a P+ type SiC substrate 101 to form a device functional layer 1;

[0046] S103 , etching the p+ type SiC epitaxial layer 102 , the n- type Ga2O3 epitaxial layer 103 and the n+ type Ga2O3 epitaxial layer 104 to form a mesa structure 2 with an inclination angle α of 70° to 80°.

[0047] Specifically, in step S1, the device functional layer 1 is first prepared: a P+ type SiC epitaxial layer 102, an n-type Ga2O3 epitaxial layer and an n+ type Ga2O3 epitaxial layer are sequentially grown on a P+ type SiC substrate 101, wherein the thickness of the P+ type SiC substrate 101 is 350 μm and the doping concentration is 5×10 18 cm -3 The thickness of the P+ type SiC epitaxial layer 102 is 1-2 μm and the doping concentration is 5×10 16 ~1×10 17 cm -3 The thickness of the n-type Ga2O3 epitaxial layer 103 is 8 to 10 μm and the doping concentration is 5×1015 ~8×10 15 cm -3 The thickness of the n+ type Ga2O3 epitaxial layer 104 is 0.8 to 1 μm, and the doping concentration is 1×10 18 ~5×10 18 cm -3 .

[0048] Next, starting from both sides of the device functional layer 1, the n+ type Ga2O3 epitaxial layer 104, the n- type Ga2O3 epitaxial layer 103 and the P+ type SiC epitaxial layer 102 are etched in sequence until the P+ type SiC substrate 101, forming a mesa structure 2 with a trapezoidal cross-section. The inclination angle α of the mesa structure 2 is 70°~80°.

[0049] like Figure 4 As shown, in step S2, alkaline earth doped silicon oxide with a thickness of 500-1000 nm is deposited on the upper surface of the mesa structure 2 by using LPCVD (Low Pressure Chemical Vapor Deposition) process to form a first passivation layer 3.

[0050] In this embodiment, the distance between the bottom of each photosensitive window 4 and the lower surface of the n+-type Ga2O3 epitaxial layer is 100 nm, the width of the photosensitive window 4 is 500-800 nm, and the interval between two adjacent photosensitive windows 4 is 500-800 nm.

[0051] See Figure 5 When making the photosensitive window, the first passivation layer 3 and at least part of the n+ type Ga2O3 epitaxial layer are opened by etching. In the direction perpendicular to the plane where the P+ type SiC substrate 101 is located, the orthographic projection of the photosensitive window 4 can be a hexagon, a circle, etc. It should be noted that this embodiment only uses Figures 5-10 Taking the three photosensitive windows 4 shown as an example, in fact, the present application does not limit the number and shape of the photosensitive windows 4, as long as the width of the photosensitive window 4 is 500-800nm ​​and the interval between two adjacent photosensitive windows 4 is 500-800nm.

[0052] In this embodiment, the material of the first passivation layer 3 includes alkaline earth doped silicon oxide. Figures 6-7 As shown, in step S4, after Ni / Au metal 5 is deposited on the upper and lower surfaces of the device respectively, ohmic contact self-alignment is performed using a rapid thermal annealing process, and then the ohmic contact is transparentized using a solution to form an anode transparent ohmic contact 6 in each photosensitive window 4 and a cathode transparent ohmic contact 7 on the lower surface of the device. At the same time, the residual metal on the first passivation layer 3 is washed away, and the first passivation layer 3 that has undergone annealing reaction is reflowed to form a moth-eye array. The steps include:

[0053] S401, using electron beam evaporation or magnetron sputtering process, depositing Ni / Au metal 5 on the upper surface and lower surface of the device respectively, and using rapid thermal annealing process to perform ohmic contact self-alignment;

[0054] S402. The ohmic contact of the annealed device is transparentized using a chemical solution to form an anode transparent ohmic contact 6 in each photosensitive window 4 and a cathode transparent ohmic contact 7 on the lower surface of the device. The Ni / Au metal 5 remaining on the surface of the first passivation layer 3 is washed away, and the first passivation layer 3 that has undergone the annealing reaction is reflowed to form a moth-eye array. The chemical solution includes nitric acid, BOE (Buffered Oxide Etch) and deionized water in a volume ratio of 1:1:5.

[0055] Specifically, in steps S401 to S402, Ni / Au metal 5 with a thickness of 150 / 50 nm is deposited on the upper and lower surfaces of the device using an electron beam evaporation or magnetron sputtering process, and then a rapid thermal annealing process is used to perform ohmic contact self-alignment, and then a Ni / SiC ohmic contact transparency treatment is performed with a liquid to form an anode transparent ohmic contact 6 and a cathode transparent ohmic contact 7. In this process, the residual metal on the surface of the first passivation layer 3 will be cleaned away, and since the material of the first passivation layer 3 includes alkaline earth doped silicon oxide, the first passivation layer after the annealing reaction can be reflowed into a moth-eye array (i.e. Figure 7 The hemispherical structure in the moth-eye array changes the light path through the moth-eye array, reducing light reflection and increasing light refraction and transmission, thereby obtaining light anti-reflection and anti-transmission capabilities, which is beneficial to improving the light efficiency of the device and thus improving the photoelectric detection performance of the single-photon ultraviolet detector.

[0056] In addition, this embodiment uses alkaline earth doped silicon oxide as a mask to implement a metal self-alignment process, which can retain a three-dimensional anti-reflection passivation structure when forming a metal electrode on the upper surface, thereby enhancing device performance.

[0057] like Figure 8 As shown, in step S5, the step of forming the anode metal electrode 8 on the upper surface of the anode transparent ohmic contact 6 located on the side wall of each photosensitive window 4 includes:

[0058] S501, depositing Al metal with a thickness of 500 to 1000 nm on the upper surface of the device;

[0059] S502 , forming an anode metal electrode 8 on the upper surface of the anode transparent ohmic contact 6 located on the side wall of each photosensitive window 4 through etching and corrosion processes.

[0060] like Figure 9 As shown, in step S6, the material of the second passivation layer 9 includes Si y Nx , x, y represent the components of N and Si respectively, where x is 1 to 3 and y is 2 to 4. y N x It has a high transmittance for detection light, so it can reduce light reflection to a certain extent. At the same time, it can serve as a second passivation layer to effectively reduce leakage on the device surface and improve light utilization.

[0061] Furthermore, if Figure 10 As shown, the step of forming the cathode metal electrode 10 on the lower surface of the cathode transparent ohmic contact 7 includes:

[0062] By using an electron beam evaporation process, Ti / Ni / Ag metals with a thickness of 200 nm / 200 nm / 1000 nm are deposited on the lower surface of the cathode transparent ohmic contact 7 to form a cathode metal electrode 10 .

[0063] It should be understood that after the detection light enters the SiC / Ga2O3 heterojunction single-photon ultraviolet detector, part of the light is absorbed and utilized by the device, and the other part is emitted from the bottom of the device. In this embodiment, after Ti / Ni / Ag metal is deposited on the lower surface of the cathode transparent ohmic contact, since metal Ag has a high reflectivity, it can serve as a back reflection layer to reflect at least part of the light back into the device, thereby improving light utilization.

[0064] Please continue to see Figure 10 The embodiment of the present invention further provides a SiC / Ga2O3 heterojunction single-photon ultraviolet detector, which is manufactured using the above-mentioned method for preparing the SiC / Ga2O3 heterojunction single-photon ultraviolet detector.

[0065] It can be seen from the above embodiments that the beneficial effects of the present invention are:

[0066] (1) The prior art uses only a single silicon carbide material as the light absorption layer during preparation. A single material has only one characteristic response peak. The present invention introduces gallium oxide during the preparation of a single-photon ultraviolet detector, which can broaden the wavelength range of the device and solve the problem of poor device performance caused by using a single SiC to prepare a single-photon ultraviolet detector. At the same time, it simplifies the preparation process without adding additional optical management processes.

[0067] (2) The material of the first passivation layer in the present invention includes alkaline earth doped silicon oxide. Therefore, after annealing, the first passivation layer can be reflowed into a moth-eye array, thereby obtaining light anti-reflection and anti-transmittance capability, which is beneficial to improving the photoelectric detection performance of the single-photon ultraviolet detector.

[0068] In the description of the present invention, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of the technical features indicated. Therefore, a feature specified as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, "plurality" means two or more, unless otherwise specifically defined.

[0069] Descriptions with reference to the terms "one embodiment," "some embodiments," "examples," "specific examples," or "some examples" mean that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in any suitable manner in any one or more embodiments or examples. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification.

[0070] The above is a further detailed description of the present invention in conjunction with specific preferred embodiments, and the specific implementation of the present invention should not be considered to be limited to these descriptions. For those skilled in the art of the present invention, without departing from the concept of the present invention, several simple deductions or substitutions can be made, which should be considered to fall within the scope of protection of the present invention.

Claims

1. A method for preparing a SiC / Ga2O3 heterojunction single-photon ultraviolet detector, characterized in that: include: preparing a device functional layer and forming a mesa structure with an inclined angle by etching; The device functional layer includes, from bottom to top, a P+ type SiC substrate, a P+ type SiC epitaxial layer, an n- type Ga2O3 epitaxial layer and an n+ type Ga2O3 epitaxial layer; depositing a first passivation layer on the upper surface of the mesa structure; Etching the first passivation layer and the n+ type Ga2O3 epitaxial layer to form a plurality of photosensitive windows; After depositing Ni / Au metal on the upper and lower surfaces of the device, respectively, a rapid thermal annealing process is used to perform ohmic contact self-alignment, followed by a chemistries to perform ohmic contact transparency treatment, forming anode transparent ohmic contacts in each of the photosensitive windows and cathode transparent ohmic contacts on the lower surface of the device. Simultaneously, residual metal on the first passivation layer is washed away, and the annealed first passivation layer is reflowed to form a moth-eye array. forming an anode metal electrode on the upper surface of the anode transparent ohmic contact located on the side wall of each photosensitive window; A second passivation layer is formed on the upper surface of the anode transparent ohmic contact in each photosensitive window, and a cathode metal electrode is formed on the lower surface of the cathode transparent ohmic contact to obtain a prepared SiC / Ga2O3 heterojunction single-photon ultraviolet detector.

2. The method for preparing the SiC / Ga2O3 heterojunction single-photon ultraviolet detector according to claim 1, characterized in that: The steps of preparing a device functional layer and forming a mesa structure with an inclination angle by etching include: Providing a P+ type SiC substrate; sequentially growing a P+ type SiC epitaxial layer, an n- type Ga2O3 epitaxial layer and an n+ type Ga2O3 epitaxial layer on one side surface of the P+ type SiC substrate to form a device functional layer; The p+ type SiC epitaxial layer, the n- type Ga2O3 epitaxial layer and the n+ type Ga2O3 epitaxial layer are etched to form a mesa structure with an inclination angle of 70° to 80°.

3. The method for preparing the SiC / Ga2O3 heterojunction single-photon ultraviolet detector according to claim 2, characterized in that: The thickness of the P+ type SiC substrate is 350 μm and the doping concentration is 5×10 18 cm -3 The thickness of the P+ type SiC epitaxial layer is 1 to 2 μm, and the doping concentration is 5×10 16 ~1×10 17 cm -3 The thickness of the n-type Ga2O3 epitaxial layer is 8 to 10 μm, and the doping concentration is 5×10 15 ~8×10 15 cm -3 The thickness of the n+ type Ga2O3 epitaxial layer is 0.8 to 1 μm, and the doping concentration is 1×10 18 ~5×10 18 cm -3 .

4. The method for preparing a SiC / Ga2O3 heterojunction single-photon ultraviolet detector according to claim 1, characterized in that: The distance between the bottom of each photosensitive window and the lower surface of the n+ type Ga2O3 epitaxial layer is 100nm, the width of each photosensitive window is 500-800nm, and the interval between two adjacent photosensitive windows is 500-800nm.

5. The method for preparing the SiC / Ga2O3 heterojunction single-photon ultraviolet detector according to claim 1, characterized in that: The material of the first passivation layer includes alkaline earth doped silicon oxide.

6. The method for preparing the SiC / Ga2O3 heterojunction single-photon ultraviolet detector according to claim 5, characterized in that: After depositing Ni / Au metal on the upper and lower surfaces of the device respectively, performing ohmic contact self-alignment using a rapid thermal annealing process, then performing ohmic contact transparency treatment using a solution to form an anode transparent ohmic contact in each photosensitive window and a cathode transparent ohmic contact on the lower surface of the device, while simultaneously washing away the residual metal on the first passivation layer and reflowing the annealed first passivation layer to form a moth-eye array, the steps comprising: Using electron beam evaporation or magnetron sputtering, Ni / Au metal is deposited on the upper and lower surfaces of the device respectively, and ohmic contact self-alignment is performed using rapid thermal annealing process; The annealed device is subjected to ohmic contact transparency treatment using a chemical solution, forming an anode transparent ohmic contact in each photosensitive window and a cathode transparent ohmic contact on the lower surface of the device, and washing away the Ni / Au metal remaining on the surface of the first passivation layer, so that the first passivation layer that has undergone the annealing reaction reflows to form a moth-eye array; the chemical solution includes nitric acid, buffered oxide etchant BOE and deionized water in a volume ratio of 1:1:

5.

7. The method for preparing a SiC / Ga2O3 heterojunction single-photon ultraviolet detector according to claim 1, characterized in that: The step of forming an anode metal electrode on the upper surface of the anode transparent ohmic contact located on the side wall of each photosensitive window includes: Depositing Al metal with a thickness of 500 to 1000 nm on the upper surface of the device, Through etching and corrosion processes, an anode metal electrode is formed on the upper surface of the anode transparent ohmic contact located on the side wall of each photosensitive window.

8. The method for preparing a SiC / Ga2O3 heterojunction single-photon ultraviolet detector according to claim 1, characterized in that: The material of the second passivation layer includes Si y N x , x and y represent the components of N and Si respectively, wherein x is 1 to 3 and y is 2 to 4.

9. The method for preparing a SiC / Ga2O3 heterojunction single-photon ultraviolet detector according to claim 1, characterized in that: The step of forming a cathode metal electrode on the lower surface of the cathode transparent ohmic contact comprises: Ti / Ni / Ag metals with thicknesses of 200nm / 200nm / 1000nm were deposited on the lower surface of the cathode transparent ohmic contact by using an electron beam evaporation process to form a cathode metal electrode.

10. A SiC / Ga2O3 heterojunction single-photon ultraviolet detector, characterized in that: The single-photon ultraviolet detector is prepared by the method for preparing the SiC / Ga2O3 heterojunction single-photon ultraviolet detector according to any one of claims 1 to 9.

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