A method for fabricating a photodetector with an ultrafast cooling structure

Abstract

The purpose of this invention is to provide a method for fabricating a photodetector with an ultrafast cooling structure, belonging to the field of heat dissipation in optoelectronic devices. The photodetector structure, from bottom to top, consists of: two mutually perpendicular diamond-based liquid flow channels, silicon, vertical graphene, and source and drain electrodes on both sides. Specifically, a diamond film is grown on a silicon substrate with microchannels by placing a molybdenum wire on it. After processing the diamond film to create new microchannels, the molybdenum wire is placed again to deposit diamond, thus creating two mutually perpendicular diamond-based liquid flow channels to obtain the ultrafast cooling structure. A vertical graphene film is then deposited on the flat surface of the silicon wafer with the ultrafast cooling structure. Finally, metal electrodes are deposited on the vertical graphene and patterned. This invention combines the excellent thermal conductivity of diamond with the construction of an ultrafast cooling structure through two mutually perpendicular diamond-based liquid flow channels, thereby achieving efficient heat dissipation to ensure the operational stability and lifespan of the photodetector.

Description

Technical Field

[0001] This invention belongs to the field of heat dissipation in optoelectronic devices, and particularly relates to a method for fabricating a photodetector with an ultrafast cooling structure. Background Technology

[0002] With the accelerating trends towards high performance, miniaturization, and integration, the high heat generated during the operation of photodetectors needs to be dissipated in a timely manner; otherwise, it can easily lead to problems such as damage to their internal structure, material deformation, and functional failure. Therefore, in order to ensure stable service and sufficient service life, good heat dissipation design has become the key to enhancing the reliability, increasing the responsivity, and improving the integration of photodetectors.

[0003] Patent CN107731903A discloses a heat dissipation structure for an integrated photodetector, designed to address the high temperature problem of multi-component circuit boards after prolonged use of photodetectors. However, this structure utilizes airflow to cool the surface of the tower-shaped heat sink, a traditional cooling method with insufficient thermal conductivity. Microchannel cooling, by increasing the contact area between the heat sink and the cooling medium per unit volume, achieves a very high surface heat transfer coefficient, offering significant advantages such as compact structure, high heat exchange efficiency, and small temperature difference. Furthermore, diamond material exhibits excellent thermal conductivity (~2000W / m²). Diamond (K) is a stable material with good physical and chemical properties, and is not easily corroded by the environment, making it an excellent material for fabricating microchannels. Therefore, for photodetectors with the aforementioned heat dissipation requirements, diamond can be used as a heat dissipation substrate, especially for microchannel structures with added flowing cooling media, enabling ultra-fast heat dissipation, thereby effectively suppressing the rise in device temperature during operation and ensuring its reliability and lifespan.

[0004] Due to the low electron mobility (1350 cm⁻¹) of traditional silicon materials. 2 The inherent characteristics of graphene, such as its zero bandgap and indirect bandgap structure, are increasingly limiting its application in optoelectronic devices. Furthermore, the operating wavelength of pure silicon-based photodetectors is also limited to the visible light and part of the infrared band, posing new challenges to the development of traditional photodetectors. Since the successful preparation of graphene, its semi-metallic zero bandgap and ultra-high mobility (>10000 cm⁻¹) have become increasingly apparent. 2 The compatibility of graphene with traditional materials such as silicon ( / v·s) has been demonstrated in optoelectronic detection applications. Among them, vertical graphene, based on its unique flake-branched structure, exhibits extremely high light absorption. Furthermore, because vertical graphene can be grown directly on any substrate without a catalyst, it offers significant advantages in photodetector applications compared to planar graphene, which typically requires metal catalysis for preparation and transfer. Summary of the Invention

[0005] To address the heat dissipation problem during device operation and promote the application development of silicon-based photodetectors, and to fully utilize the excellent properties of diamond and vertical graphene, this invention provides a method for fabricating a photodetector with an ultrafast cooling structure. Specifically, a diamond film is grown on a silicon substrate with microchannels by placing a molybdenum wire on the substrate. After processing the diamond film to create new microchannels, the molybdenum wire is placed again to deposit diamond, thus creating two mutually perpendicular diamond-based liquid flow channels to obtain an ultrafast cooling structure. A vertical graphene film is then deposited on the flat surface of the silicon wafer with the ultrafast cooling structure. Finally, a metal electrode is deposited on the vertical graphene and patterned to fabricate a photodetector with an ultrafast cooling structure.

[0006] The purpose of this invention is to provide a method for fabricating a photodetector with an ultrafast cooling structure. By combining the excellent thermal conductivity of diamond, an ultrafast cooling structure is constructed through two layers of mutually perpendicular liquid flow channels, thereby achieving efficient heat dissipation to ensure the working stability and service life of the photodetector.

[0007] To achieve the above-mentioned objectives of the present invention, the following technical solutions are provided:

[0008] This invention provides a method for fabricating a photodetector with an ultrafast cooling structure, comprising the following steps:

[0009] Step 1, Silicon substrate pretreatment:

[0010] Microchannels are processed on the surface of polished silicon wafers, and the processed silicon wafers are then ultrasonically cleaned.

[0011] Step 2, Place the molybdenum wire:

[0012] Molybdenum wires of uniform size are placed on the microchannels of the silicon wafer;

[0013] Step 3: Diamond preparation, microchannel processing, and acid treatment:

[0014] The silicon wafer filled with molybdenum wires through microchannels is used as a substrate for diamond growth. Diamond is prepared in a deposition equipment to fully cover the surface of the silicon wafer and molybdenum wires, and then a certain thickness of diamond is grown. After the deposited diamond is ground and polished, microchannels are processed by laser in a direction perpendicular to the molybdenum wires and acid treatment is performed.

[0015] Step 4, Place the new molybdenum wire:

[0016] Molybdenum wires of uniform size are placed on the microchannels of the diamond.

[0017] Step 5, Preparation and processing of the second diamond film:

[0018] The diamond filled with molybdenum wire is placed in a deposition equipment to prepare a second diamond film. After the diamond grows to fully cover the diamond substrate and the surface of the molybdenum wire, a certain thickness is grown, and the grown diamond is ground and polished.

[0019] Step 6, Remove the molybdenum wire:

[0020] Acid treatment was used to create two layers of mutually perpendicular liquid flow channels between the molybdenum wires between the diamonds.

[0021] Step 7, Preparation of vertical graphene:

[0022] Vertical graphene films are prepared on a flat surface of a silicon substrate with liquid flow channels.

[0023] Step 8, Fabrication of the photodetector:

[0024] A metal electrode of a certain thickness is deposited on a vertical graphene film and then patterned.

[0025] Furthermore, the microchannels on the silicon wafer surface described in step 1 are processed using at least one of the following processes: laser processing, physical etching, chemical etching, and reactive ion etching.

[0026] Furthermore, the dimensions of the microchannels processed in step 1 should satisfy the following requirements: the depth of the channel is less than half of the width of the channel, and the width of the channel is less than the horizontal distance between the channels.

[0027] Furthermore, the ultrasonic cleaning described in step 1 includes ultrasonic oscillation in acetone and ethanol for 10-20 minutes respectively to remove the silicon wafer itself and contaminants generated during processing.

[0028] Furthermore, the diameter of the molybdenum wire cross-section described in step 2 must be not less than the width inside the channel and less than the horizontal distance between the channels.

[0029] Furthermore, the preparation method described in step 3 can be one of DC arc plasma jet chemical vapor deposition (DCarc plasma jet CVD) or microwave plasma chemical vapor deposition (MPCVD).

[0030] Furthermore, the thickness of the regenerated diamond after achieving full coverage of the silicon wafer and molybdenum wire, as described in step 3, is 1-3 mm.

[0031] Furthermore, the grinding and polishing method described in step 3 involves first laser-removing a 0.5-0.8 mm thick diamond from the diamond growth surface, and then using a grinding machine and a polishing machine to achieve a surface roughness (RMS) of 0.001-0.05 μm.

[0032] Furthermore, the laser processing method described in step 3 is to use an Nd:YAG laser beam to cut diamond.

[0033] Furthermore, the dimensions of the microchannels described in step 3 should meet the following requirements: the depth should not exceed 0.5 mm, the internal width of the channel should not be less than twice the depth, and the horizontal distance between channels should be greater than the internal width of the channel.

[0034] Furthermore, the acid treatment solution described in step 3 is subjected to ultrasonic cleaning or high-temperature acid boiling using one or a mixture of hydrochloric acid, sulfuric acid, and nitric acid, followed by ultrasonic cleaning with acetone and alcohol.

[0035] Furthermore, the dimensions of the molybdenum wire described in step 4 should satisfy the requirement that its length is the same as the length of the diamond microchannel, and its cross-sectional diameter is not less than the internal width of the diamond microchannel while being less than the horizontal distance between the channels, preferably being consistent with the internal width of the microchannel.

[0036] Furthermore, the thickness of the regenerated diamond after achieving full coverage of the diamond substrate and molybdenum wire, as described in step 5, is 0.5-1.5 mm.

[0037] Furthermore, the acid treatment described in step 6 involves ultrasonic cleaning with a mixed solution of aqua regia, hydrochloric acid, sulfuric acid, and nitric acid, or boiling with concentrated sulfuric acid at high temperature, followed by ultrasonic cleaning with acetone and alcohol.

[0038] Furthermore, the vertical graphene described in step 7 is prepared by radio frequency plasma enhanced chemical vapor deposition (RF-PECVD), with process parameters of temperature 600℃-900℃, gas pressure 50-150Pa, radio frequency power 150-300W, introduction of a mixed gas of methane and hydrogen in a ratio of CH4:H2=0.5-3, growth time of 0.5-2h, and film thickness of 0.3-1.0μm; before growth, it is annealed at high temperature in an H2 gas atmosphere for 30-60min.

[0039] Furthermore, the plating method described in step 8 employs at least one of electron beam evaporation and magnetron sputtering, and the electrode material is Cr / Au with thicknesses ranging from 3 / 10nm to 10 / 50nm.

[0040] Furthermore, the patterning method in step 8 is to apply adhesive, expose and develop, etch, and strip to remove the adhesive.

[0041] The key to the implementation of this invention lies in:

[0042] 1. The microchannel dimensions must ensure that the internal width of the channel is less than the horizontal distance between channels. Silicon wafers and diamond microchannels are integral parts of the liquid flow channels and also ensure the fixation of molybdenum wires. Excessively wide internal channels can cause the molybdenum wires to stack, affecting the subsequent fabrication of diamond-based liquid flow channels.

[0043] 2. The dimensions of the molybdenum wires must be consistent, and must be no less than the width inside the channels while being less than the horizontal distance between channels. Using molybdenum wires as the metal mask for preparing diamond films to form an ultrafast cooling structure with liquid flow channels requires appropriate dimensions to ensure that the molybdenum wires are flatly fixed on the microchannels and that heat dissipation is uniform within the liquid flow channels.

[0044] 3. After diamond is grown to fully cover the substrate and the surface of the molybdenum wire, a further layer of diamond of a certain thickness is grown. During the initial growth stage, a low methane gas ratio must be maintained to prevent excessively rapid diamond growth on the surface of the molybdenum wire, ensuring uniform diamond deposition and connection for subsequent lateral diamond expansion. After the diamond film is fully covered by the molybdenum wire and substrate, an epitaxial regrowth of a certain thickness is necessary to facilitate subsequent processing.

[0045] 4. Use acid to treat the molybdenum wire. This can remove the molybdenum wire and also effectively remove the graphite carbon produced after processing, grinding, and polishing diamond. Finally, ultrasonic cleaning with acetone and alcohol can remove organic matter and any possible metal residues.

[0046] 5. Vertical graphene films are fabricated on a flat surface of a silicon substrate with diamond-based liquid flow channels, with a film thickness of 0.3-1.0 μm. The thickness of the graphene film can be adjusted through various process parameters. If it is too thin, the light absorption rate will be low, affecting the photoelectric conversion efficiency and thus the responsivity. If it is too thick, it will be detrimental to subsequent device fabrication.

[0047] The advantages of this invention are:

[0048] 1. The ultra-fast cooling structure provided by this invention combines the high thermal conductivity of diamond with the higher heat transfer capacity of microchannels compared to traditional heat dissipation structures. When applied, the addition of flowing liquid as a cooling medium can dissipate the heat generated during device operation with extremely high efficiency.

[0049] 2. The two mutually perpendicular liquid flow channels designed in this invention ensure the temperature stability of the liquid flow channel in the middle layer through the pure diamond-based liquid flow channel in the bottom layer, thereby enabling the liquid flow channel in the middle layer to continuously dissipate heat from the photodetector, effectively suppressing the temperature rise of the device to ensure reliability and lifespan.

[0050] 3. The vertical graphene growth method used in this invention, where graphene is grown directly on a silicon wafer, avoids various problems associated with traditional transfer techniques and simplifies the fabrication process. The resulting graphene film offers advantages such as precise thickness control, high repeatability, retention of broad-spectrum absorption, and high photoelectric conversion efficiency. Attached Figure Description

[0051] Figure 1 This is a three-dimensional structural diagram of the photodetector with an ultrafast cooling structure according to the present invention;

[0052] In the diagram: 1.1-Diamond, 1.2-Silicon, 1.3-Vertical graphene, 1.4-Metal drain, 1.5-Metal source, 1.6-First layer liquid flow channel, 1.7-Second layer liquid flow channel.

[0053] Figure 2 This is a flowchart illustrating the fabrication process of the photodetector with an ultrafast cooling structure according to the present invention.

[0054] In the figure: (a) - silicon substrate pretreatment, (b) placement of molybdenum wire, (c) diamond preparation, microchannel fabrication and acid treatment, (d) placement of new molybdenum wire, (e) preparation and fabrication of the second diamond film, (f) removal of molybdenum wire, (g) preparation of vertical graphene, (h) fabrication of photodetector; 2.1 - silicon, 2.2 - molybdenum wire, 2.3 - diamond, 2.4 - first layer liquid flow channel, 2.5 - second layer liquid flow channel, 2.6 - vertical graphene, 2.7 - metal drain, 2.8 - metal source. Detailed Implementation

[0055] The technical solution of the present invention will be further described below with reference to specific embodiments.

[0056] Example 1

[0057] 1) A microgroove structure was fabricated on the surface of a polished silicon wafer using laser processing. The groove depth was 150μm, the groove width was 300μm, and the horizontal distance between the grooves was 300μm. The processed silicon wafer was cleaned by ultrasonic cleaning with acetone for 20 minutes, then transferred to alcohol for ultrasonic cleaning for 20 minutes, and then dried for later use.

[0058] 2) Select a molybdenum wire with a diameter of 0.3 mm and place it on the microchannel of the silicon wafer;

[0059] 3) The silicon wafer filled with molybdenum wire was placed in a microwave plasma chemical vapor deposition (IPV) system to deposit diamond. Diamond was deposited to fully cover the silicon wafer and molybdenum wire surface, followed by the growth of a 2mm thick layer of diamond. 0.5mm of the grown diamond was then removed by cutting. The surface was then ground and polished to a roughness of RMS=50nm. Microchannels with a depth of 200μm, a width of 400μm, and a horizontal spacing of 400μm were then cut using an Nd:YAG laser beam. Finally, the diamond was ultrasonically cleaned in nitric acid solution, followed by ultrasonic cleaning with acetone for 20 minutes, then transferred to alcohol for ultrasonic cleaning for 20 minutes, and finally dried.

[0060] 4) Select a molybdenum wire with a diameter of 0.4 mm and place it on the microchannels of the diamond;

[0061] 5) The diamond filled with molybdenum wire was placed in a microwave plasma chemical vapor deposition (IPV) apparatus to prepare deposited diamond. After preparing diamond to fully cover the diamond substrate and the surface of the molybdenum wire, a 1.2 mm thick diamond was grown, and then ground and polished until the roughness reached RMS=10 nm.

[0062] 6) The polished diamond is placed in a concentrated sulfuric acid solution for acid boiling to effectively remove the molybdenum wire and remove the non-diamond carbon generated in the microchannels and during processing, so as to obtain a silicon wafer with an ultra-fast cooling structure. Then, it is ultrasonically cleaned with acetone for 20 minutes, then transferred to alcohol for ultrasonic cleaning for 20 minutes, and then dried.

[0063] 7) Place the silicon substrate with the ultrafast cooling structure flat side up in an RF plasma-enhanced chemical vapor deposition furnace to deposit a vertical graphene film. The growth temperature is 750℃, the RF power is 300W, the working pressure is maintained at 50Pa, CH4:H2=1.5, the growth time is 45min, and the film thickness is 0.4μm. Before growth, the film is annealed at high temperature in H2 atmosphere for 30min.

[0064] 8) Photoresist was spin-coated onto vertical graphene, and electrode patterns were exposed using photolithography. Cr / Au electrodes with thicknesses of 10 nm and 20 nm were deposited on the surface of the vertical graphene film using electron beam evaporation. The device was patterned using a lift-off process to remove the original photoresist, resulting in a photodetector with an ultrafast cooling structure.

[0065] Example 2

[0066] 1) A microgroove structure is fabricated on the surface of a polished silicon wafer using laser processing. The groove depth is 20μm, the groove width is 50μm, and the horizontal distance between the grooves is 50μm. The processed silicon wafer is cleaned by ultrasonic cleaning with acetone for 20min, then transferred to alcohol for ultrasonic cleaning for 20min, and then dried for later use.

[0067] 2) Select a molybdenum wire with a diameter of 0.05 mm and place it on the microchannel of the silicon wafer;

[0068] 3) A silicon wafer filled with molybdenum wire was placed in a DC arc plasma jet chemical vapor deposition (DCAL) system to deposit diamond. Diamond was deposited to fully cover the silicon wafer and molybdenum wire surface, followed by the growth of a 2mm thick layer of diamond. 0.6mm of the grown diamond was then removed by cutting. The surface was then ground and polished to a roughness of RMS=50nm. Microchannels with a depth of 100μm, a width of 200μm, and a horizontal spacing of 200μm were then cut using an Nd:YAG laser beam. Finally, the diamond was ultrasonically cleaned in concentrated hydrochloric acid, followed by ultrasonic cleaning with acetone for 20 minutes, then transferred to alcohol for ultrasonic cleaning for 20 minutes, and finally dried.

[0069] 4) Select a molybdenum wire with a diameter of 0.2 mm and place it on the microchannels of the diamond;

[0070] 5) The diamond filled with molybdenum wire was placed in a DC arc plasma jet chemical vapor deposition equipment to prepare deposited diamond. After preparing diamond to fully cover the diamond substrate and the surface of the molybdenum wire, a 1 mm thick layer of diamond was grown, and then ground and polished until the roughness reached RMS=20 nm.

[0071] 6) The polished diamond is placed in a concentrated sulfuric acid solution for acid boiling to effectively remove the molybdenum wire and remove the non-diamond carbon generated in the microchannels and during processing, so as to obtain a silicon wafer with an ultra-fast cooling structure. Then, it is ultrasonically cleaned with acetone for 20 minutes, then transferred to alcohol for ultrasonic cleaning for 20 minutes, and then dried.

[0072] 7) Place the silicon substrate with the ultrafast cooling structure flat side up in an RF plasma-enhanced chemical vapor deposition furnace to deposit a vertical graphene film. The growth temperature is 700℃, the RF power is 250W, the working pressure is maintained at 50Pa, CH4:H2=1, the growth time is 1h, and the film thickness is 1.0μm. Before growth, the film is annealed at high temperature in H2 gas atmosphere for 30min.

[0073] 8) Photoresist was spin-coated onto vertical graphene, and electrode patterns were exposed using photolithography. Cr / Au electrodes with thicknesses of 10 nm and 40 nm were deposited on the surface of the vertical graphene film using electron beam evaporation. The device was patterned using a lift-off process to remove the original photoresist, resulting in a photodetector with an ultrafast cooling structure.

[0074] Example 3

[0075] 1) A microgroove structure was fabricated on the surface of a polished silicon wafer using laser processing. The groove depth was 100μm, the groove width was 400μm, and the horizontal distance between the grooves was 400μm. The processed silicon wafer was cleaned by ultrasonic cleaning with acetone for 20 minutes, then transferred to alcohol and ultrasonicated for 20 minutes, and then dried for later use.

[0076] 2) Select a molybdenum wire with a diameter of 0.4 mm and place it on the microchannel of the silicon wafer;

[0077] 3) A silicon wafer filled with molybdenum wire was placed in a DC arc plasma jet chemical vapor deposition (DCAL) system to deposit diamond. Diamond was deposited to fully cover the silicon wafer and molybdenum wire surface, followed by the growth of a 3mm thick layer of diamond. 0.8mm of the grown diamond was then removed by cutting. The surface was then ground and polished to a roughness of RMS=20nm. Microchannels with a depth of 100μm, a width of 600μm, and a horizontal spacing of 700μm were then cut using an Nd:YAG laser beam. Finally, the diamond was ultrasonically cleaned in aqua regia, followed by ultrasonic cleaning with acetone for 20 minutes, then transferred to alcohol for ultrasonic cleaning for 20 minutes, and finally dried.

[0078] 4) Select a molybdenum wire with a diameter of 0.6 mm and place it on the microchannels of the diamond;

[0079] 5) The diamond filled with molybdenum wire was placed in a microwave plasma chemical vapor deposition (IPD) apparatus to prepare deposited diamond. After preparing diamond to fully cover the diamond substrate and the surface of the molybdenum wire, a 0.8 mm thick diamond layer was grown, and then ground and polished until the roughness reached RMS=1 nm.

[0080] 6) The polished diamond is placed in a concentrated sulfuric acid solution for acid boiling to effectively remove the molybdenum wire and remove the non-diamond carbon generated in the microchannels and during processing, so as to obtain a silicon wafer with an ultra-fast cooling structure. Then, it is ultrasonically cleaned with acetone for 20 minutes, then transferred to alcohol for ultrasonic cleaning for 20 minutes, and then dried.

[0081] 7) Place the silicon substrate with the ultrafast cooling structure flat side up in an RF plasma-enhanced chemical vapor deposition furnace to deposit a vertical graphene film. The growth temperature is 650℃, the RF power is 230W, the working pressure is maintained at 60Pa, CH4:H2=1, and the growth time is 1h. The film thickness is 0.7μm. Before growth, the film is annealed at high temperature in an H2 atmosphere for 45min.

[0082] 8) Photoresist was spin-coated onto vertical graphene, and electrode patterns were exposed using photolithography. Cr / Au electrodes with thicknesses of 3 nm and 20 nm were deposited on the surface of the vertical graphene film using electron beam evaporation. The device was patterned using a lift-off process to remove the original photoresist, resulting in a photodetector with an ultrafast cooling structure.

[0083] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A method for fabricating a photodetector with an ultrafast cooling structure, characterized in that, The molybdenum wire is placed on the silicon substrate with micro channels to grow diamond film, and after processing new micro channels on the diamond film, the molybdenum wire is placed again to deposit diamond, and the two-layer diamond-based liquid flow channels perpendicular to each other are obtained by preparing the super-fast cooling structure, and then the vertical graphene film is deposited on the flat surface of the silicon substrate with the super-fast cooling structure, and finally the metal electrode is plated on the vertical graphene and patterned to prepare the photodetector with the super-fast cooling structure; The specific preparation steps are as follows: Step 1, silicon substrate pretreatment: micro channel processing is performed on the surface of the polished silicon wafer, and the processed silicon wafer is ultrasonically cleaned; Step 2, place the molybdenum wire: select a molybdenum wire of the same size and place it on the micro channel of the silicon wafer; Step 3, preparation of diamond, processing of micro channel and acid treatment: the silicon wafer filled with molybdenum wire after micro channel is used as the substrate for diamond growth, and is placed in the deposition equipment to prepare diamond to cover the surface of the silicon wafer and the molybdenum wire, and then a certain thickness of diamond is grown, and after the deposited diamond is ground and polished, the micro channel is processed in the direction perpendicular to the molybdenum wire and subjected to acid treatment; Step 4, place new molybdenum wire: select a molybdenum wire of the same size and place it on the micro channel of the diamond; Step 5, preparation and processing of the second layer of diamond film: place the diamond filled with molybdenum wire in the deposition equipment to prepare the second layer of diamond film, grow the diamond to cover the surface of the diamond substrate and the molybdenum wire, and then grow a certain thickness, and grind and polish the grown diamond; Step 6, remove the molybdenum wire: use acid to treat the molybdenum wire between the diamonds to obtain two-layer liquid flow channels perpendicular to each other; Step 7, preparation of vertical graphene: prepare a vertical graphene film on the flat surface of the silicon substrate with the liquid flow channels; Step 8, preparation of photodetector: plate a certain thickness of metal electrode on the vertical graphene film and pattern it.

2. The method of claim 1, wherein the photodetector having a super-fast cooling structure is prepared by the steps of: The size of the micro channel processed in step 1 should meet the requirements that the internal depth of the channel is less than half of the internal width of the channel, and the internal width of the channel is less than the horizontal distance between the channels. ​ 3. The method for fabricating a photodetector with an ultrafast cooling structure as described in claim 1, characterized in that, The size of the molybdenum wire in step 2 should meet the requirements that the diameter is not less than the width of the internal channel and is less than the horizontal distance between the channels.

4. The method for fabricating a photodetector with an ultrafast cooling structure as described in claim 1, characterized in that, The thickness of the diamond grown after the silicon wafer and the molybdenum wire are fully covered in step 3 is 1-3 mm.

5. The method for fabricating a photodetector with an ultrafast cooling structure as described in claim 1, characterized in that, The grinding and polishing method in step 3 is to first cut off 0.5-0.8 mm thick diamond on the diamond growth surface by laser, and then use a grinding machine and a polishing machine to make the surface roughness (RMS) reach 0.001-0.05 μm.

6. The method for fabricating a photodetector with an ultrafast cooling structure as described in claim 1, characterized in that, The size of the micro channel in step 3 should meet the requirements that the depth is not greater than 0.5 mm, the internal width of the channel is not less than twice the depth, and the horizontal distance between the channels is greater than the internal width of the channel.

7. The method of claim 1, wherein the photodetector having the super-fast cooling structure is prepared by a process comprising: The size of the molybdenum wire in step 4 should meet the requirements that the length is the same as the length of the diamond micro channel, and the cross-sectional size diameter is not less than the internal width of the diamond micro channel and is less than the horizontal distance between the channels. ​ 8. The method for fabricating a photodetector with an ultrafast cooling structure as described in claim 1, characterized in that, The thickness of the diamond grown after the diamond substrate and the molybdenum wire are fully covered in step 5 is 0.5-1.5 mm.

9. The method for fabricating a photodetector with an ultrafast cooling structure as described in claim 1, characterized in that, The vertical graphene is prepared by radio frequency plasma enhanced chemical vapor deposition (RF-PECVD) in step 7, and the thickness of the grown film is 0.3-1.0 μm; before growth, high-temperature annealing in H2 gas atmosphere is performed for 30-60 min.

10. The method of claim 1, wherein the photodetector having a super-fast cooling structure is prepared by the steps of: The plating method in step 8 adopts at least one of electron beam evaporation and magnetron sputtering, the electrode material is Cr / Au, the thicknesses are 3 / 10 nm-10 / 50 nm respectively, and the patterning method is glue coating, exposure and development, etching and glue stripping. ​

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