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

Abstract

The invention discloses a SiC / Ga2O3 heterojunction single-photon ultraviolet detector and a preparation method thereof, and the method comprises the steps: preparing a device function layer, and etching to form a mesa structure with an inclination angle; 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 photosensitive window; after Ni / Au metal is respectively deposited on the upper surface and the lower surface of the device, ohmic contact self-alignment is carried out, then ohmic contact transparency processing is carried out, anode transparent ohmic contact is formed in each photosensitive window, and cathode transparent ohmic contact is formed on the lower surface of the device; forming an anode metal electrode on the upper surface of the anode transparent ohmic contact on the side wall of each photosensitive window; and forming a second passivation layer on the upper surface of the anode transparent ohmic contact in each photosensitive window, and forming a cathode metal electrode on the lower surface of the cathode transparent ohmic contact. According to the invention, the problem of low device performance caused by using a single SiC material to prepare a single-photon ultraviolet detector is solved.

Description

Technical Field

[0001] The 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 work in Geiger mode, which requires the application of a bias voltage exceeding the breakdown voltage (usually the excess voltage is 1 to 5V). Therefore, the materials selected for the preparation of ultraviolet single-photon detectors need to have a high critical breakdown field strength to achieve the working goal.

[0003] As an excellent representative of the third-generation semiconductor materials, silicon carbide 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 preparation method thereof. The technical problem to be solved by the present invention is achieved by 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 Ni / Au metal is deposited on the upper surface and the lower surface of the device respectively, the ohmic contact is self-aligned by using a rapid thermal annealing process, and then the ohmic contact is transparentized by using a liquid medicine to form 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 at the same time, the residual metal on the first passivation layer is washed away, so that the first passivation layer after the annealing reaction 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 inclined angle by etching comprises:

[0013] Providing a P+ type SiC substrate;

[0014] On one side surface of the P+ type SiC substrate, a P+ type SiC epitaxial layer, an n- type Ga2O3 epitaxial layer and an n+ type Ga2O3 epitaxial layer are sequentially grown 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 1-2 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 0.8-1 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 Ni / Au metal is deposited on the upper surface and the lower surface of the device respectively, the ohmic contact self-alignment is performed by using a rapid thermal annealing process, and then the ohmic contact is transparentized by using a liquid medicine to form 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 at the same time, the residual metal on the first passivation layer is washed away, and the first passivation layer after the annealing reaction is reflowed to form a moth-eye array, comprising:

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

[0021] The annealed device is subjected to ohmic contact transparency treatment using a chemical solution, an anode transparent ohmic contact is formed in each of the photosensitive windows, a cathode transparent ohmic contact is formed on the lower surface of the device, and the Ni / Au metal remaining on the surface of the first passivation layer is washed away, so that the first passivation layer that has undergone annealing reaction flows back into a moth-eye array; the chemical solution includes nitric acid, buffered oxide etching solution 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 1-3 and y is 2-4.

[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] By using an electron beam evaporation process, Ti / Ni / Ag metals with a thickness of 200nm / 200nm / 1000nm are deposited on the lower surface of the cathode transparent ohmic contact 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 by 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, and the single material has only one characteristic response peak. The present invention introduces gallium oxide during the preparation of the 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 the 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 reduction and reflection enhancement 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 It 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 It 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 is further described in detail below with reference to specific embodiments, but the embodiments of the present invention are not limited thereto.

[0036] Figure 1 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, preparing a device functional layer 1, and forming 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 surface and the lower surface of the device respectively, the ohmic contact self-alignment is performed by using a rapid thermal annealing process, and then the ohmic contact is transparentized by using a liquid medicine 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, and at the same time, the residual metal on the first passivation layer 3 is washed away, so that the first passivation layer 3 after the annealing reaction 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 a device functional layer 1 and forming a 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, wherein the inclination angle α is 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, and 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 also 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 process. 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 to 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 surface and the lower surface of the device respectively, the ohmic contact self-alignment is performed by using a rapid thermal annealing process, and then the ohmic contact is transparentized by using a liquid medicine 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, and at the same time, the residual metal on the first passivation layer 3 is washed away, and the first passivation layer 3 after the annealing reaction is reflowed to form a moth-eye array, comprising:

[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, using a liquid medicine to perform ohmic contact transparency treatment on the annealed device, forming an anode transparent ohmic contact 6 in each photosensitive window 4, forming a cathode transparent ohmic contact 7 on the lower surface of the device, and washing away the Ni / Au metal 5 remaining on the surface of the first passivation layer 3, so that the first passivation layer 3 after annealing reaction flows back to form a moth-eye array; the liquid medicine 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 by electron beam evaporation or magnetron sputtering process, and then ohmic contact self-alignment is performed by rapid thermal annealing process, and then Ni / SiC ohmic contact transparency treatment is performed by liquid medicine to form anode transparent ohmic contact 6 and cathode transparent ohmic contact 7. In this process, the residual metal on the surface of the first passivation layer 3 will be washed away, and since the material of the first passivation layer 3 includes alkaline earth doped silicon oxide, the first passivation layer after 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, reduces light reflection, increases light refraction and transmission, and obtains light anti-reflection and anti-transmission capabilities, which is beneficial to improving the light efficiency of the device and further 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 the performance of the device.

[0057] like Figure 8 As shown, in step S5, the step of 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 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 Fig. 9 As shown, in step S6, the material of the second passivation layer 9 includes Si y Nx , x and 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 to the 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 Fig.10 As shown, the step of forming a 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 200nm / 200nm / 1000nm 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 be used 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 Fig.10 The embodiment of the present invention also provides a SiC / Ga2O3 heterojunction single-photon ultraviolet detector, which is prepared by the above-mentioned preparation method of 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, and the single material has only one characteristic response peak. The present invention introduces gallium oxide during the preparation of the 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 the 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 reduction and reflection enhancement 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 as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0069] The description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means 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 may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine different embodiments or examples described in this specification.

[0070] The above contents are further detailed descriptions of the present invention in combination with specific preferred embodiments, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, several simple deductions or substitutions can be made without departing from the concept of the present invention, which should be regarded as falling within the protection scope 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 Ni / Au metal is deposited on the upper surface and the lower surface of the device respectively, the ohmic contact is self-aligned by using a rapid thermal annealing process, and then the ohmic contact is transparentized by using a liquid medicine to form 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 at the same time, the residual metal on the first passivation layer is washed away, so that the first passivation layer after the annealing reaction 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 step of preparing a device functional layer and forming a mesa structure with an inclined angle by etching comprises: Providing a P+ type SiC substrate; On one side surface of the P+ type SiC substrate, a P+ type SiC epitaxial layer, an n- type Ga2O3 epitaxial layer and an n+ type Ga2O3 epitaxial layer are sequentially grown 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 0.8-1 μm and the doping concentration is 1×10 18 ~5×10 18 cm -3 .

4. The method for preparing the 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 Ni / Au metal is deposited on the upper surface and the lower surface of the device respectively, the ohmic contact self-alignment is performed by using a rapid thermal annealing process, and then the ohmic contact is transparentized by using a liquid medicine to form 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 at the same time, the residual metal on the first passivation layer is washed away, and the first passivation layer after the annealing reaction is reflowed to form a moth eye array, comprising: Using electron beam evaporation or magnetron sputtering process, Ni / Au metal is deposited on the upper and lower surfaces of the device respectively, and the 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, an anode transparent ohmic contact is formed in each of the photosensitive windows, a cathode transparent ohmic contact is formed on the lower surface of the device, and the Ni / Au metal remaining on the surface of the first passivation layer is washed away, so that the first passivation layer that has undergone annealing reaction flows back into a moth-eye array; the chemical solution includes nitric acid, buffered oxide etching solution BOE and deionized water in a volume ratio of 1:1:

5.

7. The method for preparing the 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 the 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 1-3 and y is 2-4.

9. The method for preparing the 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: By using an electron beam evaporation process, Ti / Ni / Ag metals with a thickness of 200nm / 200nm / 1000nm are deposited on the lower surface of the cathode transparent ohmic contact to form a cathode metal electrode.

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

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