A gallium nitride epitaxial layer growth and stripping method based on hexagonal boron nitride

Abstract

The present invention provides a method for growing and stripping a gallium nitride epitaxial layer based on hexagonal boron nitride. The method utilizes the strong surface tension of an organic solvent, uses ultrasonic conditions to destroy the van der Waals forces between hexagonal boron nitride layers, and then uses tape for mechanical stripping to achieve the purpose of stripping gallium nitride. Compared with the existing technologies that use laser stripping, chemical stripping, and substrate grinding, the present invention does not require special experimental equipment and chemical treatment, is simple and easy to implement, has low cost, and is time-saving. It reduces damage to the epitaxial film during the stripping process, and the substrate can be recycled multiple times. The present invention can be applied to the stripping and transfer of semiconductor devices, can remove substrate restrictions, and further improve the performance and reliability of the device; and before epitaxial gallium nitride, the crystallization quality of the aluminum nitride layer is improved through a high-temperature thermal annealing process, and high-quality gallium nitride films can be obtained subsequently.

Description

Technical Field

[0001] The present invention belongs to the field of semiconductor technology, and in particular relates to a method for growing and stripping a gallium nitride epitaxial layer based on hexagonal boron nitride. Background Art

[0002] Gallium nitride (GN) is a typical representative of third-generation semiconductors. In recent years, it has been widely used in radio frequency devices, high-power power electronics, and optoelectronic devices. It is considered a core technology supporting the development of strategic emerging industries such as new energy, rail transportation, electronic information, and national defense. Currently, epitaxial GaN growth is typically performed on heterogeneous substrates such as sapphire, silicon, and silicon carbide. Large lattice mismatches and thermal expansion coefficient mismatches affect crystal quality. Furthermore, the low thermal conductivity of sapphire substrates reduces the performance and reliability of high-power devices. Hexagonal boron nitride (HBN), a layered Group III nitride, is suitable for use as an intercalation layer for growing GaN. Furthermore, the weak van der Waals forces between HBN layers allow for mechanical separation of the epitaxial layer from the substrate and transfer to other substrates. Transferring to substrates with high thermal conductivity can address device heat dissipation issues; transferring to flexible substrates can meet the needs of next-generation flexible and wearable optoelectronic and electronic devices.

[0003] Traditional methods for stripping gallium nitride include laser stripping, chemical stripping, and substrate grinding. Laser stripping uses a high-power ultraviolet pulsed laser to irradiate the gallium nitride / sapphire interface from the back of the sapphire substrate. The heating causes the gallium nitride to decompose, thereby stripping the gallium nitride and the sapphire substrate. However, this damages the gallium nitride film, and the equipment is expensive and the process is complex. Chemical stripping first grows a sacrificial layer on the sapphire substrate, and then uses a chemical etching solution to selectively remove the sacrificial layer to achieve damage-free stripping of the gallium nitride, but the stripping speed is slow. Reference K. Pantzas et al. Journal of Crystal Growth 435 (2016) uses ZnO as a sacrificial layer and removes it by HCl etching, which takes several hours at room temperature. The substrate grinding process is costly, the substrate cannot be recycled, and it is very time-consuming. Therefore, a new and effective method for stripping gallium nitride is urgently needed. Summary of the Invention

[0004] In order to solve the above problems existing in the prior art, the present invention provides a method for growing and exfoliating a gallium nitride epitaxial layer based on hexagonal boron nitride. The technical problem to be solved by the present invention is achieved through the following technical solutions:

[0005] The present invention provides a method for growing and stripping a gallium nitride epitaxial layer based on hexagonal boron nitride, comprising:

[0006] Step 1: Get copper foil;

[0007] Step 2: Clean and heat treat the copper foil;

[0008] Step 3: growing hexagonal boron nitride on the copper foil after heat treatment;

[0009] Step 4: transferring the grown hexagonal boron nitride to the obtained substrate;

[0010] Step 5: Magnetron sputtering an aluminum nitride layer on the hexagonal boron nitride transferred to the substrate;

[0011] Step 6: performing a high-temperature thermal annealing treatment on the structure formed by sputtering the aluminum nitride layer;

[0012] Step 7: Using MOCVD to epitaxially grow a GaN layer on the AlN layer after high-temperature thermal annealing.

[0013] Step 8: Use organic solution to assist mechanical exfoliation of the GaN layer.

[0014] Optionally, step 2 includes:

[0015] Step 21: Ultrasonic cleaning of the copper foil in dilute hydrochloric acid for 10-20 minutes;

[0016] Step 22: ultrasonically clean the copper foil in deionized water for 10-20 minutes;

[0017] Step 23: Rinse the copper foil after deionized water in ethanol solution for 2-3 times;

[0018] Step 24: Use nitrogen to blow dry the copper foil;

[0019] Step 25: Cut the dried copper foil into 1cm x 1cm pieces and place them in the center of the quartz tube.

[0020] Step 26: Evacuate the quartz tube to 3-10 Pa and introduce hydrogen to normal pressure;

[0021] Step 27: Repeat step 26 until the air in the quartz tube is removed;

[0022] Step 28: In an atmosphere of a mixed gas of argon and hydrogen, heat the quartz tube to 1050° C. and anneal for 1-6 hours.

[0023] Optionally, step 3 includes:

[0024] Step 31: Place the treated copper foil in the constant temperature zone in the middle of the quartz tube in the tube furnace, and place the precursor ammonia borane at the air inlet end of the quartz tube;

[0025] Step 32: Turn on the vacuum pump to evacuate the quartz tube to 10 Pa, introduce argon gas to normal pressure, and repeat several times to remove the air in the tube;

[0026] Step 33: 40-50 sccm of argon gas is introduced into the quartz tube to maintain the pressure in the tube at a low pressure of 40-55 Pa;

[0027] Step 34: heating the quartz tube at a heating rate of 10°C / min from room temperature to a reaction temperature of 950-1050°C, then turning on the heating power to heat the ammonia borane at a temperature of 60-110°C;

[0028] Step 35: The gas pressure in the quartz tube is maintained constant, and hexagonal boron nitride is grown on the copper foil in the quartz tube;

[0029] Wherein, the thickness of the grown hexagonal boron nitride is 1-10nm;

[0030] Step 36: After the growth is completed, turn off the heating source and the mechanical pump, introduce argon gas into the quartz tube to normal pressure, cool it to room temperature, and then take out the hexagonal boron nitride (hBN) grown on the copper foil.

[0031] Optionally, step 4 includes:

[0032] Step 41: Use a spin coater to spin-coat a layer of polymethyl methacrylate (PMMA) solution on the surface of the copper foil on which the hexagonal boron nitride is grown, to obtain a spin-coated copper foil;

[0033] Step 42: Place the spin-coated copper foil on a heating table at 80-90°C for 10-30 minutes to remove the solvent and solidify the PMMA.

[0034] Step 43: Place the cured PMMA / hBN / Cu in a certain concentration of ammonium persulfate solution with the copper foil facing downward, and wait until the copper foil is completely corroded to obtain a PMMA / hBN film.

[0035] Step 44: Transfer the PMMA / hBN film to deionized water using a glass slide and rinse repeatedly to remove residual ammonium persulfate solution and metal ions.

[0036] Step 45: Use the substrate to fish out the PMMA / hBN film, place it on a heating table and heat it for 0.5-1 hour to allow the film to adhere to the substrate, thereby obtaining a PMMA / hBN / substrate structure sample;

[0037] Step 46: Completely immerse the PMMA / hBN / substrate structure sample in an acetone solution for 12-24 hours to dissolve and remove the PMMA, thereby obtaining an hBN / substrate.

[0038] Step 47: Take out the hBN / substrate, soak it in ethanol solution for 2-3 hours, and then take out the hBN / substrate and blow it dry with nitrogen to complete the hBN transfer process.

[0039] Optionally, the substrate in step 1 is one of sapphire, silicon, and silicon carbide substrates;

[0040] When spin coating PMMA in step 41, the speed of the coating machine can be selected to be 2000 rpm-4000 rpm.

[0041] Optionally, step 5 includes:

[0042] Step 51: Place the hexagonal boron nitride transferred onto the substrate into a magnetron sputtering reaction system, introduce high-purity argon and nitrogen, and adjust the reaction chamber pressure to 0.1-1.0 Pa;

[0043] Step 52: Using aluminum with a purity of 99.99% as a sputtering target, adjusting the reaction chamber temperature to 400-800°C, and sputtering a layer of AlN on the hBN / substrate with a thickness of 10-100 nm;

[0044] Step 53: After the temperature of the reaction chamber is lowered to room temperature, the sample is taken out to obtain an hBN / substrate on which an AlN layer is deposited, forming an AlN / hBN / substrate three-layer structure.

[0045] Optionally, step 6 includes:

[0046] Step 61: Laminating the structure formed by sputtering the aluminum nitride layer face to face with another substrate, or with the AlN surface of another three-layer structure, and placing them together in an annealing furnace for annealing to prevent AlN from decomposing at high temperatures;

[0047] Wherein, the other substrate may be sapphire;

[0048] Step 62: nitrogen is introduced into the annealing furnace, the annealing temperature is 1100-1700° C., the pressure in the furnace is 10 mbar-2000 mbar, and the annealing time is 10 min-3 h to improve the crystal quality of aluminum nitride;

[0049] Step 63: After the temperature in the furnace is lowered to room temperature, the sample is taken out to complete the annealing of the aluminum nitride layer.

[0050] Optionally, step 7 includes:

[0051] Step 71: Place the AlN / hBN / substrate formed after high-temperature annealing into an MOCVD reaction chamber, raise the temperature to 700-900° C., introduce ammonia gas, and keep the temperature for 20 minutes;

[0052] Step 72: The reaction chamber pressure is adjusted to 100-1000 mbar, the temperature is raised to 1000-1200°C, and ammonia and gallium source are introduced simultaneously, with hydrogen as a carrier gas, to grow a 1-6 μm gallium nitride layer on the AlN / hBN / substrate three-layer structure;

[0053] Step 73: After the reaction chamber temperature is lowered to room temperature, the sample is taken out to complete the growth of the gallium nitride layer to form a four-layer structure of GaN / AlN / hBN / substrate.

[0054] Optionally, step 8 includes:

[0055] Step 81: Immerse the four-layer structure formed by growing the gallium nitride layer in an organic solution, sonicate it in an ultrasonic instrument for 1-12 hours, and then rinse it with ethanol and deionized water;

[0056] Step 82: Gently apply the tape to the surface of the GaN layer, apply pressure evenly, and then slowly peel off the tape from the GaN layer.

[0057] Step 83: The tape is tightly attached to the target substrate, and some processing is performed to separate the tape from the GaN layer;

[0058] Step 84: After the tape is removed, the GaN stripping and transfer process is completed.

[0059] Optional,

[0060] In step 81, the organic solution is one of dimethylformamide, isopropyl alcohol, and benzyl benzoate;

[0061] In step 83, the tape is one of thermal release tape, water-soluble tape, and polyimide tape; the target substrate is one of diamond, flexible PET, SiO2 / Si, and copper sheet; some processing procedures include: when using thermal release tape, heating is required at a temperature of 90-120°C for 5-10 minutes to make the thermal release tape lose its stickiness; when using water-soluble tape, soaking it in deionized water until the tape is completely dissolved.

[0062] The present invention provides a method for growing and stripping a gallium nitride epitaxial layer based on hexagonal boron nitride. The method utilizes the strong surface tension of an organic solvent, uses ultrasonic conditions to destroy the van der Waals forces between hexagonal boron nitride layers, and then uses tape for mechanical stripping to achieve the purpose of stripping gallium nitride. Compared with the existing technologies that use laser stripping, chemical stripping, and substrate grinding, the present invention does not require special experimental equipment and chemical treatment, is simple and easy to implement, has low cost, and takes less time. It reduces the damage to the epitaxial film during the stripping process, and the substrate can be recycled multiple times. The present invention can be applied to the stripping and transfer of semiconductor devices, can remove substrate restrictions, and further improve the performance and reliability of the device. In addition, before epitaxial gallium nitride is grown, the crystallization quality of the aluminum nitride layer is improved through a high-temperature thermal annealing process, and a high-quality gallium nitride film can be obtained subsequently. BRIEF DESCRIPTION OF THE DRAWINGS

[0063] Figure 1 This is a schematic flow chart of a method for growing and stripping a gallium nitride epitaxial layer based on hexagonal boron nitride provided by the present invention;

[0064] Figure 2 is a schematic diagram of transferring hBN to a sapphire substrate in an embodiment of the present invention;

[0065] Figure 3 Schematic diagram of the three-layer structure of AlN / hBN / sapphire substrate in an embodiment of the present invention;

[0066] Figure 4 Schematic diagram of a four-layer structure of GaN / AlN / hBN / sapphire substrate in an embodiment of the present invention;

[0067] Figure 5 Schematic diagram of the structure after gallium nitride stripping and transfer in an embodiment of the present invention. DETAILED DESCRIPTION

[0068] The present invention will be further described in detail below with reference to specific examples, but the embodiments of the present invention are not limited thereto.

[0069] like Figure 1 As shown, the present invention provides a gallium nitride epitaxial layer growth and stripping method based on hexagonal boron nitride, which includes:

[0070] Step 1: Get copper foil;

[0071] Step 2: Clean and heat treat the copper foil;

[0072] As an optional embodiment of the present invention, step 2 includes:

[0073] Step 21: Ultrasonic cleaning of the copper foil in dilute hydrochloric acid for 10-20 minutes;

[0074] Step 22: ultrasonically clean the copper foil in deionized water for 10-20 minutes;

[0075] Step 23: Rinse the copper foil after deionized water in ethanol solution for 2-3 times;

[0076] Step 24: Use nitrogen to blow dry the copper foil;

[0077] Step 25: Cut the dried copper foil into 1cm x 1cm pieces and place them in the center of the quartz tube.

[0078] Step 26: Evacuate the quartz tube to 3-10 Pa and introduce hydrogen to normal pressure;

[0079] Step 27: Repeat step 26 until the air in the quartz tube is removed;

[0080] Step 28: In an atmosphere of a mixed gas of argon and hydrogen, heat the quartz tube to 1050° C. and anneal for 1-6 hours.

[0081] The content of the mixed gas of argon and hydrogen may be 200 sccm:50 sccm.

[0082] Step 3: growing hexagonal boron nitride on the copper foil after heat treatment;

[0083] As an optional embodiment of the present invention, step 3 includes:

[0084] Step 31: Place the treated copper foil in the constant temperature zone in the middle of the quartz tube in the tube furnace, and place the precursor ammonia borane at the air inlet end of the quartz tube;

[0085] Step 32: Turn on the vacuum pump to evacuate the quartz tube to 10 Pa, introduce argon gas to normal pressure, and repeat several times to remove the air in the tube;

[0086] Step 33: 40-50 sccm of argon gas is introduced into the quartz tube to maintain the pressure in the tube at a low pressure of 40-55 Pa;

[0087] Step 34: heating the quartz tube at a heating rate of 10°C / min from room temperature to a reaction temperature of 950-1050°C, then turning on the heating power to heat the ammonia borane at a temperature of 60-110°C;

[0088] Step 35: The gas pressure in the quartz tube is maintained constant, and hexagonal boron nitride is grown on the copper foil in the quartz tube;

[0089] The thickness of the grown hexagonal boron nitride is 1-10 nm.

[0090] Step 36: After the growth is completed, turn off the heating source and the mechanical pump, introduce argon gas into the quartz tube to normal pressure, cool it to room temperature, and then take out the hexagonal boron nitride (hBN) grown on the copper foil.

[0091] Step 4: transferring the grown hexagonal boron nitride to the obtained substrate;

[0092] The substrate is one of sapphire, silicon and silicon carbide substrates.

[0093] As an optional embodiment of the present invention, step 4 includes:

[0094] Step 41: Use a spin coater to spin-coat a layer of polymethyl methacrylate (PMMA) solution on the surface of the copper foil on which the hexagonal boron nitride is grown, to obtain a spin-coated copper foil;

[0095] In this step, the speed of the spin coater can be selected to be 2000 rpm-4000 rpm when spin coating PMMA.

[0096] Step 42: Place the spin-coated copper foil on a heating table at 80-90°C for 10-30 minutes to remove the solvent and cure the PMMA.

[0097] Step 43: Place the cured PMMA / hBN / Cu in a certain concentration of ammonium persulfate solution with the copper foil facing downward, and wait until the copper foil is completely corroded to obtain a PMMA / hBN film.

[0098] Step 44: Transfer the PMMA / hBN film to deionized water using a glass slide and rinse repeatedly to remove residual ammonium persulfate solution and metal ions.

[0099] Step 45: Use the substrate to fish out the PMMA / hBN film, place it on a heating table and heat it for 0.5-1 hour to allow the film to adhere to the substrate, thereby obtaining a PMMA / hBN / substrate structure sample;

[0100] Step 46: Completely immerse the PMMA / hBN / substrate structure sample in an acetone solution for 12-24 hours to dissolve and remove the PMMA, thereby obtaining an hBN / substrate.

[0101] Step 47: Take out the hBN / substrate and soak it in ethanol solution for 2-3 hours, then take out the hBN / substrate and blow dry it with nitrogen. Figure 2 After the transfer process is completed, the hBN layer is located on the sapphire substrate.

[0102] Step 5: Magnetron sputtering an aluminum nitride layer on the hexagonal boron nitride transferred to the substrate;

[0103] As an optional embodiment of the present invention, step 5 includes:

[0104] Step 51: Place the hexagonal boron nitride transferred onto the substrate into a magnetron sputtering reaction system, introduce high-purity argon and nitrogen, and adjust the reaction chamber pressure to 0.1-1.0 Pa;

[0105] Step 52: Using aluminum with a purity of 99.99% as a sputtering target, adjusting the reaction chamber temperature to 400-800°C, and sputtering a layer of AlN on the hBN / substrate with a thickness of 10-100 nm;

[0106] Step 53: After the reaction chamber temperature is lowered to room temperature, the sample is taken out to obtain the hBN / substrate on which the AlN layer is deposited. Figure 3 As shown, a three-layer structure of AlN / hBN / substrate is formed.

[0107] Step 6: performing a high-temperature thermal annealing treatment on the structure formed by sputtering the aluminum nitride layer;

[0108] As an optional embodiment of the present invention, step 6 includes:

[0109] Step 61: Laminating the structure formed by sputtering the aluminum nitride layer face to face with another substrate, or with the AlN surface of another three-layer structure, and placing them together in an annealing furnace for annealing to prevent AlN from decomposing at high temperatures;

[0110] Wherein, the other substrate may be sapphire;

[0111] Step 62: nitrogen is introduced into the annealing furnace, the annealing temperature is 1100-1700° C., the pressure in the furnace is 10 mbar-2000 mbar, and the annealing time is 10 min-3 h to improve the crystal quality of aluminum nitride;

[0112] Step 63: After the temperature in the furnace is lowered to room temperature, the sample is taken out to complete the annealing of the aluminum nitride layer.

[0113] Step 7: Using MOCVD to epitaxially grow a GaN layer on the AlN layer after high-temperature thermal annealing.

[0114] As an optional embodiment of the present invention, step 7 includes:

[0115] Step 71: Place the AlN / hBN / substrate formed after high-temperature annealing into an MOCVD reaction chamber, raise the temperature to 700-900° C., introduce ammonia gas, and keep the temperature for 20 minutes;

[0116] Step 72: The reaction chamber pressure is adjusted to 100-1000 mbar, the temperature is raised to 1000-1200°C, and ammonia and gallium source are introduced simultaneously, with hydrogen as a carrier gas, to grow a 1-6 μm gallium nitride layer on the AlN / hBN / substrate three-layer structure;

[0117] The flow rates of ammonia gas and gallium source can be 130 mmol / min and 0.1 mmol / min respectively.

[0118] Step 73: After the reaction chamber temperature is lowered to room temperature, the sample is taken out to complete the growth of the gallium nitride layer to form a four-layer structure of GaN / AlN / hBN / substrate. Figure 4 shown.

[0119] Step 8: Mechanically peel off the GaN layer using an isopropyl alcohol solution.

[0120] As an optional embodiment of the present invention, step 8 includes:

[0121] Step 81: Immerse the four-layer structure formed by growing the gallium nitride layer in an organic solution, sonicate it in an ultrasonic instrument for 1-12 hours, and then rinse it with ethanol and deionized water;

[0122] Wherein, the organic solvent is one of dimethylformamide, isopropyl alcohol, and benzyl benzoate;

[0123] Step 82: Gently apply the tape to the surface of the GaN layer, apply pressure evenly, and then slowly peel off the tape from the GaN layer.

[0124] Step 83: Attach the tape tightly to the target substrate and perform some processing to separate the tape from the GaN layer;

[0125] Among them, the target substrate can be one of diamond, flexible PET, SiO2 / Si, and copper sheet. Some processing processes include: for using thermal release tape, it is necessary to heat it at a temperature of 90-120°C for 5-10 minutes to make the thermal release tape lose its stickiness; for using water-soluble tape, it is necessary to soak it in deionized water until the tape is completely dissolved and separated from the gallium nitride layer.

[0126] Step 84: After removing the tape, the gallium nitride stripping and transfer process is completed, such as Figure 5 shown.

[0127] The present invention provides a method for growing and stripping a gallium nitride epitaxial layer based on hexagonal boron nitride. The method utilizes the strong surface tension of an organic solvent, uses ultrasonic conditions to destroy the van der Waals forces between hexagonal boron nitride layers, and then uses tape for mechanical stripping to achieve the purpose of stripping gallium nitride. Compared with the existing technologies that use laser stripping, chemical stripping, and substrate grinding, the present invention does not require special experimental equipment and chemical treatment, is simple and easy to implement, has low cost, and takes less time. It reduces the damage to the epitaxial film during the stripping process, and the substrate can be recycled multiple times. The present invention can be applied to the stripping and transfer of semiconductor devices, can remove substrate restrictions, and further improve the performance and reliability of the device. In addition, before epitaxial gallium nitride is grown, the crystallization quality of the aluminum nitride layer is improved through a high-temperature thermal annealing process, and a high-quality gallium nitride film can be obtained subsequently.

[0128] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature identified as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, "plurality" means two or more, unless otherwise specifically defined.

[0129] The above is a further detailed description of the present invention in conjunction with specific preferred embodiments, and the specific implementation of the present invention should not be considered to be limited to these descriptions. For those skilled in the art of the present invention, without departing from the concept of the present invention, several simple deductions or substitutions can be made, which should be considered to fall within the scope of protection of the present invention.

Claims

1. A method for growing and exfoliating a gallium nitride epitaxial layer based on hexagonal boron nitride, characterized in that: include: Step 1: Get copper foil; Step 2: Clean and heat treat the copper foil; Step 3: growing hexagonal boron nitride on the copper foil after heat treatment; Step 4: transferring the grown hexagonal boron nitride to the obtained substrate; Step 5: Magnetron sputtering an aluminum nitride layer on the hexagonal boron nitride transferred to the substrate; Step 6: performing a high-temperature thermal annealing treatment on the structure formed by sputtering the aluminum nitride layer; Step 7: Using MOCVD to epitaxially grow a GaN layer on the AlN layer after high-temperature thermal annealing. Step 8: Mechanically stripping the gallium nitride layer using an organic solution as an aid; Step 8 includes: Step 81: Immerse the four-layer structure formed by growing the gallium nitride layer in an organic solution, sonicate it in an ultrasonic instrument for 1-12 hours, and then rinse it with ethanol and deionized water; Step 82: Gently apply the tape to the surface of the GaN layer, apply pressure evenly, and then slowly peel off the tape from the GaN layer. Step 83: The tape is tightly attached to the target substrate, and some processing is performed to separate the tape from the GaN layer; Step 84: After the tape is removed, the GaN stripping and transfer process is completed.

2. The method for growing and stripping a gallium nitride epitaxial layer based on hexagonal boron nitride according to claim 1, wherein: The step 2 includes: Step 21: Ultrasonic cleaning of the copper foil in dilute hydrochloric acid for 10-20 minutes; Step 22: ultrasonically clean the copper foil in deionized water for 10-20 minutes; Step 23: Rinse the copper foil after deionized water in ethanol solution for 2-3 times; Step 24: Use nitrogen to blow dry the copper foil; Step 25: Cut the dried copper foil into 1cm x 1cm pieces and place them in the center of the quartz tube. Step 26: Evacuate the quartz tube to 3-10 Pa and introduce hydrogen to normal pressure; Step 27: Repeat step 26 until the air in the quartz tube is removed; Step 28: In an atmosphere of a mixed gas of argon and hydrogen, heat the quartz tube to 1050° C. and anneal for 1-6 hours.

3. The method for growing and stripping a gallium nitride epitaxial layer based on hexagonal boron nitride according to claim 1, wherein: The step 3 comprises: Step 31: Place the treated copper foil in the constant temperature zone in the middle of the quartz tube in the tube furnace, and place the precursor ammonia borane at the air inlet end of the quartz tube; Step 32: Turn on the vacuum pump to evacuate the quartz tube to 10 Pa, introduce argon gas to normal pressure, and repeat several times to remove the air in the tube; Step 33: 40-50 sccm of argon gas is introduced into the quartz tube to maintain the pressure in the tube at a low pressure of 40-55 Pa; Step 34: heating the quartz tube at a heating rate of 10°C / min from room temperature to a reaction temperature of 950-1050°C, then turning on the heating power to heat the ammonia borane at a temperature of 60-110°C; Step 35: The gas pressure in the quartz tube is maintained constant, and hexagonal boron nitride is grown on the copper foil in the quartz tube; Wherein, the thickness of the grown hexagonal boron nitride is 1-10nm; Step 36: After the growth is completed, turn off the heating source and mechanical pump, introduce argon gas into the quartz tube to normal pressure, cool it to room temperature, and then take out the hexagonal boron nitride (hBN) grown on the copper foil.

4. The method for growing and stripping a gallium nitride epitaxial layer based on hexagonal boron nitride according to claim 1, wherein: The step 4 comprises: Step 41: Use a spin coater to spin-coat a layer of polymethyl methacrylate (PMMA) solution on the surface of the copper foil on which the hexagonal boron nitride is grown, to obtain a spin-coated copper foil; Step 42: Place the spin-coated copper foil on a heating table at 80-90°C for 10-30 minutes to remove the solvent and solidify the PMMA. Step 43: Place the cured PMMA / hBN / Cu in a certain concentration of ammonium persulfate solution with the copper foil facing downward, and wait until the copper foil is completely corroded to obtain a PMMA / hBN film. Step 44: Transfer the PMMA / hBN film to deionized water using a glass slide and rinse repeatedly to remove residual ammonium persulfate solution and metal ions. Step 45: Use the substrate to fish out the PMMA / hBN film, place it on a heating table and heat it for 0.5-1 hour to allow the film to adhere to the substrate, thereby obtaining a PMMA / hBN / substrate structure sample; Step 46: Completely immerse the PMMA / hBN / substrate structure sample in an acetone solution for 12-24 hours to dissolve and remove the PMMA, thereby obtaining an hBN / substrate. Step 47: Take out the hBN / substrate, soak it in ethanol solution for 2-3 hours, and then take out the hBN / substrate and blow it dry with nitrogen to complete the hBN transfer process.

5. The method for growing and stripping a gallium nitride epitaxial layer based on hexagonal boron nitride according to claim 4, wherein: The substrate in step 1 is one of sapphire, silicon, and silicon carbide substrates; When spin coating PMMA in step 41, the rotation speed of the coating machine can be selected to be 2000 rpm-4000 rpm.

6. The method for growing and stripping a gallium nitride epitaxial layer based on hexagonal boron nitride according to claim 1, wherein: The step 5 comprises: Step 51: Place the hexagonal boron nitride transferred onto the substrate into a magnetron sputtering reaction system, introduce high-purity argon and nitrogen, and adjust the pressure of the reaction chamber to 0.1-1.0 Pa; Step 52: Using aluminum with a purity of 99.99% as a sputtering target, adjusting the reaction chamber temperature to 400-800°C, and sputtering a layer of AlN on the hBN / substrate with a thickness of 10-100 nm; Step 53: After the temperature of the reaction chamber is lowered to room temperature, the sample is taken out to obtain an hBN / substrate on which an AlN layer is deposited, forming an AlN / hBN / substrate three-layer structure.

7. The method for growing and stripping a gallium nitride epitaxial layer based on hexagonal boron nitride according to claim 1, wherein: The step 6 comprises: Step 61: Laminating the structure formed by sputtering the aluminum nitride layer face to face with another substrate, or with the AlN surface of another three-layer structure, and placing them together in an annealing furnace for annealing to prevent AlN from decomposing at high temperatures; Wherein, the other substrate may be sapphire; Step 62: nitrogen is introduced into the annealing furnace, the annealing temperature is 1100-1700° C., the pressure in the furnace is 10 mbar-2000 mbar, and the annealing time is 10 min-3 h to improve the crystal quality of aluminum nitride; Step 63: After the temperature in the furnace is lowered to room temperature, the sample is taken out to complete the annealing of the aluminum nitride layer.

8. The method for growing and stripping a gallium nitride epitaxial layer based on hexagonal boron nitride according to claim 1, wherein: The step 7 comprises: Step 71: Place the AlN / hBN / substrate formed after high-temperature annealing into an MOCVD reaction chamber, raise the temperature to 700-900° C., introduce ammonia gas, and keep the temperature for 20 minutes; Step 72: The reaction chamber pressure is adjusted to 100-1000 mbar, the temperature is raised to 1000-1200°C, and ammonia and gallium source are introduced simultaneously, with hydrogen as a carrier gas, to grow a 1-6 μm gallium nitride layer on the AlN / hBN / substrate three-layer structure; Step 73: After the reaction chamber temperature is lowered to room temperature, the sample is taken out to complete the growth of the gallium nitride layer to form a four-layer structure of GaN / AlN / hBN / substrate.

9. The method for growing and stripping a gallium nitride epitaxial layer based on hexagonal boron nitride according to claim 1, wherein: The organic solution in step 81 is one of dimethylformamide, isopropyl alcohol, and benzyl benzoate; In step 83, the tape is one of thermal release tape, water-soluble tape, and polyimide tape; the target substrate is one of diamond, flexible PET, SiO2 / Si, and copper sheet; some processing procedures include: when using thermal release tape, heating is required to be performed at a temperature of 90-120°C for 5-10 minutes to make the thermal release tape lose its stickiness; when using water-soluble tape, soaking it in deionized water until the tape is completely dissolved.

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