Homotype silicon carbide gallium oxide heterojunction ultraviolet photodiode and preparation method thereof

Abstract

The invention discloses a homotype silicon carbide gallium oxide heterojunction ultraviolet photodiode and a preparation method thereof. The ultraviolet photodiode comprises a substrate, an epitaxial layer superposed on the substrate, a moth-eye array passivation layer superposed on the epitaxial layer, a Schottky contact layer superposed on the upper surface of the epitaxial layer except a sub-passivation layer, an anode superposed on the Schottky contact layer, and a passivation protection layer superposed on the moth-eye array passivation layer and the anode, the ohmic contact layer is overlaid under the substrate; the cathode is overlaid under the ohmic contact layer; wherein the moth-eye array passivation layer comprises a plurality of moth-eye-shaped sub passivation layers which are arranged at intervals; and the sub-passivation layer is made of alkaline earth doped silicon oxide. The homotype silicon carbide gallium oxide heterojunction ultraviolet photodiode provided by the invention can effectively reduce light reflection and improve the light utilization rate, and the preparation process is simple and efficient.

Description

Technical Field

[0001] The invention belongs to the technical field of semiconductor devices, and in particular relates to a homogeneous silicon carbide gallium oxide heterojunction ultraviolet photodiode and a preparation method thereof. Background Art

[0002] Silicon carbide gallium oxide heterojunction UV detectors combine the high thermal conductivity and chemical stability of SiC (silicon carbide) and the high thermal conductivity and chemical stability of Ga 2 O 3 The ultra-wide band gap and high UV sensitivity of (gallium oxide) enable efficient and stable UV light detection. Its excellent material properties make it have important application potential in the fields of UV imaging, environmental monitoring and UV communication under high temperature and high power environments.

[0003] The anti-reflection structure in the existing silicon carbide gallium oxide heterojunction ultraviolet photodiode requires additional process steps during preparation and cannot be prepared using standard equipment. Therefore, it is not conducive to industrial promotion and the preparation process is complicated. Summary of the invention

[0004] In order to solve the above problems existing in the prior art, the present invention provides a homogeneous silicon carbide gallium oxide heterojunction ultraviolet photodiode and a preparation method thereof.

[0005] The technical problem to be solved by the present invention is achieved through the following technical solutions:

[0006] In a first aspect, the present invention provides a homogeneous silicon carbide gallium oxide heterojunction ultraviolet photodiode, wherein the homogeneous silicon carbide gallium oxide heterojunction ultraviolet photodiode comprises:

[0007] substrate;

[0008] an epitaxial layer superimposed on the substrate;

[0009] A moth-eye array passivation layer superimposed on the epitaxial layer; the moth-eye array passivation layer comprises a plurality of moth-eye-shaped sub-passivation layers arranged at intervals; the material of the sub-passivation layers is alkaline earth-doped silicon oxide;

[0010] A Schottky contact layer superimposed on the upper surface of the epitaxial layer except for the sub-passivation layer;

[0011] an anode superimposed on the Schottky contact layer;

[0012] A passivation protection layer superimposed on the moth-eye array passivation layer and the anode;

[0013] an ohmic contact layer superimposed below the substrate;

[0014] A cathode is stacked below the ohmic contact layer.

[0015] Optionally, the epitaxial layer includes a first epitaxial layer and a second epitaxial layer stacked on the first epitaxial layer.

[0016] Optionally, the material of the first epitaxial layer is SiC; the material of the second epitaxial layer is Ga 2 O 3 ; The thickness of the first epitaxial layer ranges from 1.5 μm to 2 μm; The thickness of the second epitaxial layer ranges from 0.2 μm to 0.5 μm.

[0017] Optionally, the thickness of the moth-eye array passivation layer ranges from 500 nm to 1000 nm.

[0018] Optionally, the material of the ohmic contact layer is Ni; and the thickness of the ohmic contact layer is in the range of 60 nm to 70 nm.

[0019] Optionally, the material of the Schottky contact layer is Pt; and the thickness of the Schottky contact layer is in the range of 60 nm to 70 nm.

[0020] Optionally, the material of the anode is Al; the thickness of the anode ranges from 500nm to 1000nm.

[0021] Optionally, the cathode is formed by stacking Ti, Ni and Ag in sequence from bottom to top.

[0022] In a second aspect, the present invention provides a method for preparing a homogeneous silicon carbide gallium oxide heterojunction ultraviolet photodiode, the preparation method comprising:

[0023] Selecting a substrate;

[0024] growing an epitaxial layer on the substrate;

[0025] Depositing a whole surface of alkaline earth doped silicon oxide on the upper surface of the epitaxial layer, and etching the whole surface of the alkaline earth doped silicon oxide through an etching process to form an initial passivation layer array; the initial passivation layer array includes a plurality of alkaline earth doped silicon oxide blocks arranged at intervals;

[0026] While depositing a Schottky contact layer on the upper surface of the epitaxial layer except for the alkaline earth doped silicon oxide block, an ohmic contact layer is deposited on the lower surface of the substrate;

[0027] Annealing the Schottky contact layer and the ohmic contact layer using a thermal annealing process, and reflowing the alkaline earth doped silicon oxide block treated by the thermal annealing process to form a moth-eye-shaped sub-passivation layer, wherein a plurality of the sub-passivation layers form a moth-eye array passivation layer;

[0028] Performing metal deposition on the upper surface of the Schottky contact layer to form an anode;

[0029] forming a passivation protection layer on the moth-eye array passivation layer and the upper surface of the anode;

[0030] A cathode is deposited on the lower surface of the ohmic contact layer.

[0031] Optionally, before metal deposition is performed on the upper surface of the Schottky contact layer to form an anode, the preparation method further comprises:

[0032] The ohmic contact layer is transparentized using a liquid medicine, and the metal remaining on the upper surface of the moth-eye array passivation layer is removed at the same time; the volume ratio of nitric acid, BOE and deionized water in the liquid medicine is 1:1:5.

[0033] The present invention provides a homogeneous silicon carbide gallium oxide heterojunction ultraviolet photodiode, which can effectively reduce the reflection of light through the numerous depressions and protrusions formed by the multiple moth-eye-shaped sub-passivation layers arranged at intervals in the moth-eye array passivation layer, and the material of the sub-passivation layer is alkaline earth doped silicon oxide. By combining the alkaline earth doped silicon oxide with the microstructure of the moth-eye array passivation layer, the reflection of light can be further reduced and the utilization rate of light can be improved. In addition, based on the characteristics of alkaline earth doped silicon oxide, the moth-eye-shaped sub-passivation layer in the moth-eye array passivation layer can be formed by reflow in the process of preparing the Schottky contact layer and the ohmic contact layer, making the preparation of the moth-eye array passivation layer simpler, more efficient, and lower cost.

[0034] The present invention will be further described in detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 is a cross-sectional view of a homogeneous silicon carbide gallium oxide heterojunction ultraviolet photodiode provided in an embodiment of the present invention;

[0036] Figure 2 It is a schematic flow chart of a method for preparing a homogeneous silicon carbide gallium oxide heterojunction ultraviolet photodiode provided by an embodiment of the present invention;

[0037] Figure 3 It is a schematic diagram of the preparation process of a homogeneous silicon carbide gallium oxide heterojunction ultraviolet photodiode provided in an embodiment of the present invention.

[0038] Figure numerals: 1, substrate; 2, first epitaxial layer; 3, second epitaxial layer; 4, moth-eye array passivation layer; 5, Schottky contact layer; 6, ohmic contact layer; 7, anode; 8, passivation protection layer; 9, cathode. DETAILED DESCRIPTION

[0039] 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.

[0040] In order to solve the problem that the existing anti-reflection structure is difficult to realize and the preparation process is complicated, the embodiment of the present invention provides a homogeneous silicon carbide gallium oxide heterojunction ultraviolet photodiode, see Figure 1 , Figure 1 It is a cross-sectional view of a homogeneous silicon carbide gallium oxide heterojunction ultraviolet photodiode provided in an embodiment of the present invention. The homogeneous silicon carbide gallium oxide heterojunction ultraviolet photodiode includes a substrate 1, an epitaxial layer, a moth-eye array passivation layer 4, a Schottky contact layer 5, an anode 7, an ohmic contact layer 6, a cathode 9 and a passivation protection layer 8.

[0041] The substrate 1 refers to the basic material for growing semiconductor crystals and is an important basis for manufacturing semiconductor devices such as transistors and integrated circuits.

[0042] In the embodiment of the present invention, the material of the substrate 1 may be SiC. SiC has the characteristics of high thermal conductivity and strong chemical stability. The thickness of the substrate 1 may be 350 μm, and the concentration may be 5×10 18 cm -3 .

[0043] Specifically, the substrate 1 may be an n+ type SiC substrate.

[0044] In the embodiment of the present invention, the epitaxial layer is stacked on the substrate 1. The epitaxial layer stacked on the substrate 1 can be used to achieve matching between semiconductor materials with different lattice constants, thereby realizing the preparation of a heterostructure.

[0045] In the embodiment of the present invention, the epitaxial layer includes a first epitaxial layer 2 and a second epitaxial layer 3 stacked on the first epitaxial layer 2 .

[0046] The material of the first epitaxial layer 2 is SiC, which is the same as the material of the substrate 1. Therefore, the first epitaxial layer 2 is homoepitaxial. The material of the second epitaxial layer 3 is Ga 2 O 3 , Ga 2 O 3 It has the characteristics of ultra-wide band gap and high ultraviolet light sensitivity, and its material is different from that of the substrate 1 , so the second epitaxial layer 3 is heteroepitaxial.

[0047] In the embodiment of the present invention, the thickness of the first epitaxial layer 2 is in the range of 1.5 μm to 2 μm, and the thickness of the second epitaxial layer 3 is in the range of 0.2 μm to 0.5 μm.

[0048] In the embodiment of the present invention, the moth-eye array passivation layer 4 is stacked on the epitaxial layer.

[0049] In an embodiment of the present invention, the moth-eye array passivation layer 4 includes a plurality of spaced-apart moth-eye-shaped sub-passivation layers. The numerous depressions and protrusions formed by the plurality of spaced-apart moth-eye-shaped sub-passivation layers can effectively reduce light reflection and increase light absorption, thereby improving the performance of the ultraviolet photodiode.

[0050] In the embodiment of the present invention, the thickness of the moth-eye array passivation layer 4 is in the range of 500nm to 1000nm, the interval between every two sub-passivation layers is in the range of 500nm to 800nm, and the width of the sub-passivation layer is in the range of 500nm to 800nm.

[0051] In an embodiment of the present invention, the material of the sub-passivation layer is alkaline earth doped silicon oxide. The doping element in the alkaline earth doped silicon oxide may be alkaline earth metals such as calcium (Ca), magnesium (Mg) and strontium (Sr). By doping the alkaline earth metal into silicon oxide, the electronic and optical properties of the oxide can be improved.

[0052] Combining alkaline earth doped silicon oxide with the microstructure of the moth eye array in the moth eye array passivation layer 4 can further reduce reflection and improve the light incidence and absorption efficiency. In addition, when alkaline earth doped silicon oxide is used as the material of the sub-passivation layer, when the Schottky contact layer 5 and the ohmic contact layer 6 are subjected to thermal annealing during the preparation of the device, the alkaline earth doped silicon oxide will also be affected by the annealing treatment to form the moth eye array passivation layer 4 through reflow, making the preparation of the moth eye array simpler, more efficient, and less costly.

[0053] In the embodiment of the present invention, each sub-passivation layer in the moth-eye array passivation layer 4 is hemispherical, and its bottom surface can be circular or hexagonal, etc., which is not limited here.

[0054] In the embodiment of the present invention, the Schottky contact layer 5 is superimposed on the region of the upper surface of the epitaxial layer except the sub-passivation layer. The Schottky contact layer 5 refers to a layer formed by the contact between the metal and the semiconductor. In the Schottky contact layer 5, a potential barrier is formed between the metal and the semiconductor, and this potential barrier can control the flow of electrons and has a rectifying effect.

[0055] In the embodiment of the present invention, the material of the Schottky contact layer 5 is Pt (platinum); the thickness of the Schottky contact layer 5 is in the range of 60 nm to 70 nm.

[0056] In the embodiment of the present invention, the anode 7 is superimposed on the Schottky contact layer 5. The material of the anode 7 is Al (aluminum), and the anode 7 made of Al has excellent conductivity and adhesion, and low cost. The thickness of the anode 7 can range from 500nm to 1000nm.

[0057] In the embodiment of the present invention, the passivation protection layer 8 is superimposed on the moth-eye array passivation layer 4 and the anode 7 .

[0058] In the embodiment of the present invention, the passivation protection layer 8 located on the moth-eye array passivation layer 4 can further reduce the surface light reflection. In addition, the passivation protection layer 8 can serve as a barrier between the moth-eye array passivation layer 4 and the anode 7 to prevent the layers below the passivation protection layer 8 from being contaminated, oxidized or corroded, thereby maintaining the stability of the ultraviolet photodiode and extending the service life of the device. The passivation protection layer 8 can also provide a certain degree of thermal isolation.

[0059] In the embodiment of the present invention, the material of the passivation protection layer 8 can be Si y N x (Silicon nitride), the thickness of which can range from 500nm to 600nm.

[0060] In the embodiment of the present invention, the ohmic contact layer 6 is superimposed under the substrate 1 , and the cathode 9 is superimposed under the ohmic contact layer 6 .

[0061] The ohmic contact layer 6 between the substrate 1 and the cathode 9 can provide a low resistance connection between the substrate 1 and the cathode 9, which is beneficial to the input and output of current.

[0062] In the embodiment of the present invention, the material of the ohmic contact layer 6 is Ni (nickel), and the thickness of the ohmic contact layer 6 is in the range of 60 nm to 70 nm.

[0063] In an embodiment of the present invention, the cathode 9 is formed by stacking Ti (titanium), Ni and Ag (silver) in sequence from bottom to top. Among them, Ti has good adhesion. Ni has good electrical conductivity and high hardness, which can further enhance the electrical conductivity between metals and provide a stable support. Ag has excellent electrical conductivity and extremely low resistivity. The cathode 9 structure of titanium-nickel-silver can effectively optimize the performance, mechanical strength and chemical stability of the device.

[0064] In the embodiment of the present invention, the moth-eye array passivation layer 4 includes a plurality of moth-eye-shaped sub-passivation layers arranged at intervals, which form a plurality of depressions and protrusions, which can effectively reduce the reflection of light, and the material of the sub-passivation layer is alkaline earth-doped silicon oxide, and the alkaline earth-doped silicon oxide is combined with the microstructure of the moth-eye array passivation layer 4, which can further reduce the reflection of light and improve the utilization rate of light. In addition, based on the characteristics of alkaline earth-doped silicon oxide, the moth-eye-shaped sub-passivation layer in the moth-eye array passivation layer 4 can be formed by reflow during the preparation of the Schottky contact layer 5 and the ohmic contact layer 6, so that the preparation of the moth-eye array passivation layer 4 is simpler, more efficient, and has lower cost.

[0065] In an embodiment of the present invention, a method for preparing a homogeneous silicon carbide gallium oxide heterojunction ultraviolet photodiode is also provided. Figure 2 , Figure 21 is a flow chart of a method for preparing a homogeneous silicon carbide gallium oxide heterojunction ultraviolet photodiode provided by an embodiment of the present invention, and the preparation method specifically comprises the following steps:

[0066] Step S201, selecting substrate 1.

[0067] In the embodiment of the present invention, the selected substrate 1 is made of SiC, with a thickness of 350 μm and a concentration of 5×10 18 cm -3 Specifically, the substrate 1 may be an n+ type SiC substrate.

[0068] Step S202 , growing an epitaxial layer on the substrate 1 .

[0069] In the embodiment of the present invention, the epitaxial layer may be grown by processes such as PECVD (Plasma Enhanced Chemical Vapor Deposition) or magnetron sputtering.

[0070] In the embodiment of the present invention, the epitaxial layer includes a first epitaxial layer 2 and a second epitaxial layer 3 superimposed on the first epitaxial layer 2. The specific growth process of the epitaxial layer is as follows:

[0071] See also Figure 3 (a) in Figure 3 1 is a schematic diagram of the preparation process of a homogeneous silicon carbide gallium oxide heterojunction ultraviolet photodiode provided by an embodiment of the present invention, wherein a first epitaxial layer 2 is grown on a substrate 1 by a process such as PECVD or magnetron sputtering. The material of the first epitaxial layer 2 may be SiC, the thickness may range from 1.5 μm to 2 μm, and the concentration may range from 1×10 16 cm -3 ~2×10 16 cm -3 Specifically, the first epitaxial layer 2 may be an n-type SiC epitaxial layer.

[0072] See also Figure 3 In (b), a second epitaxial layer 3 is grown on the first epitaxial layer 2 by a process such as PECVD or magnetron sputtering. The material of the second epitaxial layer 3 can be Ga 2 O 3 , the thickness range can be 0.2μm~0.5μm, and the concentration range can be 1×10 16 cm -3 ~2×10 16 cm -3 Specifically, the second epitaxial layer 3 may be n-type Ga 2 O 3 Epitaxial layer.

[0073] Step S203, depositing alkaline earth doped silicon oxide on the entire surface of the epitaxial layer, and etching the entire surface of the alkaline earth doped silicon oxide through an etching process to form an initial passivation layer array; the initial passivation layer array includes a plurality of alkaline earth doped silicon oxide blocks arranged at intervals.

[0074] See also Figure 3 In (c), alkaline earth doped silicon oxide is first deposited on the upper surface of the epitaxial layer using LPCVD (Low Pressure Chemical Vapor Deposition) process. The thickness of the alkaline earth doped silicon oxide on the entire surface ranges from 500nm to 1000nm.

[0075] See also Figure 3 In (d), a window is formed by etching downward from the upper surface of the entire alkaline earth doped silicon oxide using a photolithography and etching process. The width of the window is in the range of 500nm to 800nm, and the interval is in the range of 500nm to 800nm, that is, the interval between the multiple alkaline earth doped silicon oxide blocks arranged at intervals in the initial passivation layer array is in the range of 500nm to 800nm, and the width of each alkaline earth doped silicon oxide block is in the range of 500nm to 800nm. Specifically, the window pattern can be hexagonal, circular, etc.

[0076] Step S204 , while depositing a Schottky contact layer 5 on the upper surface of the epitaxial layer except for the alkaline earth doped silicon oxide block, an ohmic contact layer 6 is deposited on the lower surface of the substrate 1 .

[0077] In the embodiment of the present invention, the electron beam evaporation or magnetron sputtering process can be used to perform the entire metal deposition on the front and back sides of the device, that is, the entire metal deposition is performed on the upper surface of the alkaline earth doped silicon oxide block and the epitaxial layer and the lower surface of the substrate 1, and the ohmic contact layer 6 is formed on the lower surface of the substrate 1. Figure 3 (e) in .

[0078] After annealing, the metal in the area on the upper surface of the epitaxial layer except the alkaline earth doped silicon oxide block is retained to form a Schottky contact layer 5, see Figure 3 (f) in.

[0079] In the embodiment of the present invention, the material of the Schottky contact layer 5 is Pt, and the thickness of the Schottky contact layer 5 is in the range of 60 nm to 70 nm. The material of the ohmic contact layer 6 is Ni, and the thickness of the ohmic contact layer 6 is in the range of 60 nm to 70 nm.

[0080] Step S205 , annealing the Schottky contact layer 5 and the ohmic contact layer 6 using a thermal annealing process, and at the same time, the alkaline earth doped silicon oxide block treated by the thermal annealing process is reflowed to form a moth-eye shaped sub-passivation layer; multiple sub-passivation layers form a moth-eye array passivation layer 4 .

[0081] In the embodiment of the present invention, a rapid thermal annealing process is used to anneal the Schottky contact layer 5 and the ohmic contact layer 6. The annealing condition is to anneal for 180 seconds at a temperature of 1000° C. in an inert gas atmosphere. The inert gas may be nitrogen or helium.

[0082] Each alkaline earth doped silicon oxide block treated by the thermal annealing process will reflow to form a moth-eye-shaped sub-passivation layer, thereby obtaining a moth-eye array passivation layer 4, see Figure 3 (f) in the figure obtains the light subtraction and reflection enhancement capability, further improving the photoelectric detection performance of the device.

[0083] In one implementation, after the annealing treatment, before the next step of performing metal deposition on the upper surface of the Schottky contact layer 5 to form the anode 7, the preparation method further includes:

[0084] The ohmic contact layer 6 is made transparent using a chemical solution, and the metal remaining on the upper surface of the moth-eye array passivation layer 4 is removed at the same time; the volume ratio of nitric acid, BOE (Buffered Oxide Etch) and deionized water in the chemical solution is 1:1:5.

[0085] In the embodiment of the present invention, the ohmic contact layer 6 is made transparent and the metal remaining on the upper surface of the moth-eye array passivation layer 4 is removed to reduce light reflection and improve light transmission performance.

[0086] Step S206 , performing metal deposition on the upper surface of the Schottky contact layer 5 to form an anode 7 .

[0087] In the embodiment of the present invention, electron beam evaporation or magnetron sputtering is used to deposit Al metal on the entire surface of the device, and the thickness of the deposition ranges from 500nm to 1000nm. Then, photolithography and etching processes are used to etch from the upper surface of the deposited Al metal to the bottom, and part of the Al metal on the surface of the sub-passivation layer is etched away, and the Al metal on the upper surface of the Schottky contact layer 5 is retained to form the anode 7, see Figure 3 (g) in.

[0088] Step S207 , forming a passivation protection layer 8 on the upper surfaces of the moth-eye array passivation layer 4 and the anode 7 .

[0089] In the embodiment of the present invention, a SiyNx anti-reflection surface passivation protective layer can be formed on the device surface photosensitive window by using PECVD and photolithography etching process. Figure 3 (h) in.

[0090] Step S208 , depositing a cathode 9 on the lower surface of the ohmic contact layer 6 .

[0091] In the embodiment of the present invention, the device is flipped over so that the lower surface of the ohmic contact layer 6 faces upward, and then 200nm of Ti, 200nm of Ni and 1000nm of Ag are sequentially deposited on the lower surface of the ohmic contact layer 6 using an electron beam evaporation process to form a cathode 9, which can also serve as a back reflection layer to increase the light utilization rate of the device, see Figure 3 (i) in .

[0092] In the embodiment of the present invention, the moth-eye array passivation layer 4 is formed by reflowing while annealing the Schottky contact layer 5 and the ohmic contact layer 6 using a thermal annealing process during the metal self-alignment process of the device, without introducing additional processing steps, so that the preparation of the moth-eye array passivation layer 4 is simpler, more efficient, and has lower costs, solving the problems of difficult design of the anti-reflection structure of the existing device and complex preparation process. The numerous depressions and protrusions formed by the multiple moth-eye-shaped sub-passivation layers arranged at intervals included in the moth-eye array passivation layer 4 can effectively reduce the reflection of light, and the material of the sub-passivation layer is alkaline earth-doped silicon oxide. By combining the alkaline earth-doped silicon oxide with the microstructure of the moth-eye array passivation layer 4, the reflection of light can be further reduced and the utilization rate of light can be improved.

[0093] It should be noted that the terms "first", "second", etc. are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present invention. Instead, they are merely examples of devices and methods consistent with some aspects of the present invention.

[0094] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features 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 representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features 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 the different embodiments or examples described in this specification.

[0095] Although the present invention is described herein in conjunction with various embodiments, in the process of implementing the claimed invention, those skilled in the art can understand and implement other changes to the disclosed embodiments by viewing the drawings and the disclosed content. In the description of the present invention, the term "comprising" does not exclude other components or steps, "one" or "an" does not exclude multiple situations, and "multiple" means two or more, unless otherwise clearly and specifically limited. In addition, certain measures are recorded in different embodiments, but this does not mean that these measures cannot be combined to produce good results.

[0096] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0097] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0098] 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 homogeneous silicon carbide gallium oxide heterojunction ultraviolet photodiode, characterized in that: The isotype silicon carbide gallium oxide heterojunction ultraviolet photodiode comprises: substrate; an epitaxial layer superimposed on the substrate; A moth-eye array passivation layer superimposed on the epitaxial layer; the moth-eye array passivation layer comprises a plurality of moth-eye-shaped sub-passivation layers arranged at intervals; the material of the sub-passivation layers is alkaline earth-doped silicon oxide; A Schottky contact layer superimposed on the upper surface of the epitaxial layer except for the sub-passivation layer; an anode superimposed on the Schottky contact layer; A passivation protection layer superimposed on the moth-eye array passivation layer and the anode; an ohmic contact layer superimposed below the substrate; A cathode is stacked below the ohmic contact layer.

2. The isotype silicon carbide gallium oxide heterojunction ultraviolet photodiode according to claim 1, characterized in that: The epitaxial layer includes a first epitaxial layer and a second epitaxial layer stacked on the first epitaxial layer.

3. The isotype silicon carbide gallium oxide heterojunction ultraviolet photodiode according to claim 2, characterized in that: The material of the first epitaxial layer is SiC; the material of the second epitaxial layer is Ga2O3; the thickness of the first epitaxial layer is in the range of 1.5 μm to 2 μm; the thickness of the second epitaxial layer is in the range of 0.2 μm to 0.5 μm.

4. The isotype silicon carbide gallium oxide heterojunction ultraviolet photodiode according to claim 1, characterized in that: The thickness of the moth-eye array passivation layer ranges from 500nm to 1000nm.

5. The isotype silicon carbide gallium oxide heterojunction ultraviolet photodiode according to claim 1, characterized in that: The material of the ohmic contact layer is Ni; the thickness of the ohmic contact layer is in the range of 60nm to 70nm.

6. The isotype silicon carbide gallium oxide heterojunction ultraviolet photodiode according to claim 1, characterized in that: The material of the Schottky contact layer is Pt; the thickness of the Schottky contact layer is in the range of 60nm to 70nm.

7. The isotype silicon carbide gallium oxide heterojunction ultraviolet photodiode according to claim 1, characterized in that: The material of the anode is Al; the thickness of the anode is in the range of 500nm to 1000nm.

8. The isotype silicon carbide gallium oxide heterojunction ultraviolet photodiode according to claim 1, characterized in that: The cathode is formed by stacking Ti, Ni and Ag in sequence from bottom to top.

9. A method for preparing a homogeneous silicon carbide gallium oxide heterojunction ultraviolet photodiode, characterized in that: The preparation method comprises: Selecting a substrate; growing an epitaxial layer on the substrate; Depositing a whole surface of alkaline earth doped silicon oxide on the upper surface of the epitaxial layer, and etching the whole surface of the alkaline earth doped silicon oxide through an etching process to form an initial passivation layer array; the initial passivation layer array includes a plurality of alkaline earth doped silicon oxide blocks arranged at intervals; While depositing a Schottky contact layer on the upper surface of the epitaxial layer except for the alkaline earth doped silicon oxide block, an ohmic contact layer is deposited on the lower surface of the substrate; Annealing the Schottky contact layer and the ohmic contact layer using a thermal annealing process, and reflowing the alkaline earth doped silicon oxide block treated by the thermal annealing process to form a moth-eye-shaped sub-passivation layer, wherein a plurality of the sub-passivation layers form a moth-eye array passivation layer; Performing metal deposition on the upper surface of the Schottky contact layer to form an anode; forming a passivation protection layer on the moth-eye array passivation layer and the upper surface of the anode; A cathode is deposited on the lower surface of the ohmic contact layer.

10. The preparation method according to claim 9, characterized in that: Before metal deposition is performed on the upper surface of the Schottky contact layer to form an anode, the preparation method further comprises: The ohmic contact layer is transparentized using a liquid medicine, and the metal remaining on the upper surface of the moth-eye array passivation layer is removed at the same time; the volume ratio of nitric acid, BOE and deionized water in the liquid medicine is 1:1:5.

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