Easily stripped hBN single crystal growth formula and growth method

Abstract

The invention discloses a growth formula and a growth method of an easy-to-peel hBN single crystal. The formula comprises the following components: a specific metal solvent material, a precursor material, a reducing agent material and shielding gas. A Fe-Ni-Cr ternary metal solvent with a specific proportion is adopted, and a BN powder isolation layer is formed under hBN crystals in an induction mode. According to different formula parameters, in combination with a specially designed three-section program cooling strategy, controllable growth of the hBN crystal size and the powder isolation layer thickness is realized. Through the protection of the BN powder isolating layer, an operator can peel the hBN crystal along the interface of the isolating layer by using a hard medium (such as a blade) without directly contacting the crystal, so that the mechanical damage to the hBN crystal in the peeling process is effectively avoided. The method ensures that the grown hBN crystal can be completely stripped from the surface of the metal ingot, and finally the large-area hBN single crystal with complete structure and considerable thickness is obtained.

Description

Technical Field

[0001] The invention relates to an easily peelable hBN single crystal growth formula and growth method, and belongs to the fields of wide bandgap semiconductor growth, metal melting method crystal growth, etc. Background Art

[0002] Hexagonal boron nitride (hBN) has attracted widespread attention due to its exceptional electronic, optical, and mechanical properties. It has been widely applied in cutting-edge fields such as neutron detection, deep ultraviolet photonics, single-photon emission, and quantum sensing. Furthermore, hBN's atomically flat surface, virtually free of charge traps and dangling bonds, makes it an ideal substrate material for other two-dimensional crystals, such as graphene, molybdenum disulfide (MoS2), and tungsten disulfide (WS2). Combined with its wide bandgap of approximately 5.9 eV, excellent chemical stability, and superior thermal conductivity, hBN can also serve as an ultrathin insulator or gate dielectric, encapsulation protection layer, and thermal management layer, playing a key role in a variety of electronic devices. However, these applications place high demands on the material's crystalline quality, especially in nanoscale devices, where even tiny defects can severely impact performance. Due to its high melting point of 3400 K, hBN is difficult to directly grow using traditional melt growth methods (such as the Czochralski method). At present, although large-area hBN films with controllable thickness can be prepared by chemical vapor deposition (CVD), molecular beam epitaxy (MBE) or sputtering deposition, the films prepared by these methods often have vacancies, grain boundaries and line defects, resulting in low crystal quality. 2g The full width at half maximum of the Raman vibration mode is usually 20–30 cm -1 In comparison, the metal melt method shows great potential in preparing large-area, high-quality hBN crystals. This method does not rely on a specific substrate, and the reaction is closer to thermodynamic equilibrium, which is conducive to the relaxation of defects. Under high temperature and high pressure conditions, high-quality hBN single crystals have been successfully grown using a variety of metal solvents. However, high-pressure conditions limit its feasibility in large-scale applications. It is worth noting that studies have shown that high-quality hBN crystals comparable to those under high-pressure conditions can also be grown under normal pressure. For example, this goal can be achieved using nickel-molybdenum (Ni-Mo), nickel-chromium (Ni-Cr), and iron-chromium (Fe-Cr) solution systems.

[0003] In terms of crystal separation, thermal release tape is usually used to peel hBN crystals at this stage, but this method can easily cause the crystals to break. If complete and thicker crystals are required, the metal ingot usually needs to be etched with strong acid. However, the high corrosion resistance of chromium-containing metals makes this method costly and environmentally unfriendly. Recent studies have shown that independent triangular hBN crystals grown using iron-based metal solvents not only have high crystal quality, but also effectively maintain their structural integrity, making them particularly suitable for peeling operations. Therefore, the use of iron-based alloy solutions to grow triangular hBN crystals provides an efficient and feasible technical path for achieving complete peeling of hBN crystals. Summary of the Invention

[0004] When growing hBN crystals using the metal solvent method, there is a problem of the metal solvent tightly adhering to the grown hBN crystal after solidification. This can cause the hBN crystal structure to be damaged during the peeling process, or even break into small fragments, which seriously limits its prospects in practical applications. To address this problem, the present invention provides a growth formula and growth method for hBN single crystals that are easy to peel. Utilizing a specific ratio of Fe–Ni–Cr ternary metal solvent material and a specially designed three-stage programmed cooling strategy, a layer of BN powder isolation layer is induced to form between the hBN single crystal and the metal ingot. This BN powder isolation layer can effectively isolate the hBN crystal from the metal ingot, thereby ensuring that the hBN crystal maintains its structural integrity during the peeling process. Based on this invention, large-area and appreciable-thick hBN single crystals can be stably obtained.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] On the one hand, the present invention provides a hBN single crystal growth formula that is easy to peel, characterized in that it includes the following components: a specific metal solvent material, a precursor material, a reducing agent material, and a protective gas; the mass of the specific metal solvent material is G metal The material can be a Fe-Ni-Cr ternary alloy prepared in a specific mass ratio and having a purity of not less than 99.9%, or a mixture of Fe, Ni, and Cr metal elements with a purity of not less than 99.9%, wherein the mass fractions of Fe, Ni, and Cr are M and M, respectively. Fe 、M Ni 、M Cr And the following conditions are met: M Fe +M Ni +M Cr =100wt%, 60wt%<M Fe +M Ni <75wt%,32.5wt%<M Fe <75wt%; the precursor material is of mass G hBN , with a purity of not less than 99.9% and an average diameter of DhBN hBN powder, of which G hBN Satisfy 10<G metal / G hBN <40, D hBN The range is 1–20 μm and the allowable error is ±3 μm; the reducing agent material is a material with a mass of G c , purity not less than 99.95% and average diameter D C Toner, D C The range is 5-50 μm and the allowable error is ±5 μm; the protective gas is one of nitrogen, helium or argon with a concentration of 3N (99.9%) or above.

[0007] Preferably, the specific mass G of the specific metal solvent material metal The volume V of the specific container (unit: cm 3 ) is determined to satisfy the formula: 504.89×E×V=G metal ×(63.99×M Fe +56.58×M Ni +70.04×M Cr ), where E is the volume fraction of the solvent material, ranging from 0.5 to 0.7. The volume fraction E represents the proportion of the metal solvent material to the container volume V. When the volume fraction is controlled to be 0.5-0.7, it helps to ensure the smoothness of the solvent surface in the high-temperature molten state. If the amount of metal used is too small, it may not be able to effectively cover the bottom of the container during the cooling process, resulting in an uneven or curled solvent surface, affecting the crystal growth interface. If the amount is too large, there is a risk of damage to the container due to thermal expansion and contraction during the heating, melting or reaction process.

[0008] Preferably, since hBN growth requires two elements, B and N, the metal solvent needs to have the function of dissolving both B atoms and N atoms. Compared with Ni and Fe, Cr has good solubility for N element. Incorporating 25–40wt% Cr helps to improve the solubility of the metal solvent for N element, thereby promoting the growth of hBN crystals. Both Fe and Ni have high solubility for B element, which helps to promote the uniform distribution of B element in the metal solvent. In addition, increasing the mass fraction M of Fe and Ni Fe 、M Ni At a specific temperature during the cooling process, the metal solvent can be supersaturated. In this state, the solvent can induce BN powder to redeposit and accumulate under the hBN crystal to form an isolation layer, thereby promoting the separation of the hBN crystal from the metal ingot surface.

[0009] Preferably, the specific mass G of the reducing agent material carbon powder is c Depends on the quality of the metal solvent material G metal , satisfying the formula: G c=2×P×G metal , where P is the reduction coefficient, ranging from 0.2% to 0.5%, and the specific value depends on the airtightness of the heating equipment. The carbon powder added to the metal solvent will remove the residual oxygen added to the cavity through a reduction reaction, preventing oxygen from forming a metal oxide layer with the metal at high temperature, or free oxygen elements from forming BO with B atoms. x These oxides hinder the diffusion of boron and nitrogen in the metal solvent, thereby inhibiting the growth of hBN crystals. Furthermore, the addition of an appropriate amount of carbon powder evens out the distribution of nitrogen on the metal ingot surface, improving its diffusion and dissolution behavior in the alloy. Given the high solubility of boron in the alloy and the limiting factor of nitrogen availability, the addition of carbon powder significantly increases the probability of boron–nitrogen pairing and nucleation efficiency, thereby improving the growth quality of hBN crystals.

[0010] On the other hand, the present invention provides a method for growing hBN single crystals with an easy-to-peel off formula, characterized in that the formula of the growth raw materials includes the following components: a specific metal solvent material, a precursor material, a reducing agent material, and a protective gas; the mass of the specific metal solvent material is G metal The material can be a Fe-Ni-Cr ternary alloy prepared in a specific mass ratio and having a purity of not less than 99.9%, or a mixture of Fe, Ni, and Cr metal elements with a purity of not less than 99.9%, wherein the mass fractions of Fe, Ni, and Cr are M and M, respectively. Fe 、M Ni 、M Cr And the following conditions are met: M Fe +M Ni +M Cr =100wt%, 60wt%<M Fe +M Ni <75wt%,32.5wt%<M Fe <75wt%; the precursor material is of mass G hBN , with a purity of not less than 99.9% and an average diameter of D hBN hBN powder, of which G hBN Satisfy 10<G metal / G hBN <40, D hBN The range is 1–20 μm and the allowable error is ±3 μm; the reducing agent material is a material with a mass of G c , purity not less than 99.95% and average diameter D C Toner, D C The range is 5–50 μm with an allowable error of ±5 μm; the protective gas is one of nitrogen, helium, or argon at 3N (99.9%) or higher. The method for growing an easily peelable hBN single crystal using this recipe includes the following steps: a) Use a volume V of 20–200 cm 3 A high-temperature resistant container made of alumina, aluminum nitride, or zirconium oxide, equipped with a sealed lid made of the same material. The container and lid must be ultrasonically cleaned for 15 minutes before use, then dried at 120°C for 6 hours. b) evenly spreading the precursor material on the bottom of the container; c) stirring the specific metal solvent material and the reducing agent material in a blender at 200-500 rpm for 30-60 minutes and then placing them in a container to form a layered structure with the precursor material below; d) After covering the container with a lid, place the filled container in a heating device cavity with controllable temperature, uniform temperature field, and good airtightness; e) Use protective gas to replace the air in the heating equipment cavity. When the residual air volume is less than one thousandth, continue to introduce protective gas at a flow rate of 0.02-0.04m / min; f) starting the heating device, raising the system temperature to a holding temperature T0 (1550–1600°C), and holding the temperature at this temperature for a time of H (12–48 hours) to melt the specific metal solvent material to form a metal solution to dissolve the precursor material; g) After the holding temperature is completed, a three-stage programmed cooling strategy is used to control the crystal growth process: the first stage: slowly cooling from the holding temperature T0 to the supersaturation temperature point T1 (1425-1450°C) at a rate of 1-5°C / h, during which only triangular hBN single crystals grow; the second stage: when the temperature drops to T1, the temperature is accelerated to the solidification point T2 (1300-1350°C) of the solution at a rate of 2-5°C / h, during which the BN powder isolation layer continues to grow under the hBN single crystal; the third stage: when the temperature drops to T2, the temperature is rapidly cooled to 900-1100°C at a rate of 5-20°C / min, allowing the metal solution to solidify into a metal ingot, which is then naturally cooled to room temperature, completing the crystal growth process; h) After the system is cooled to room temperature, the condensed sample is taken out from the container and the grown hBN single crystal is peeled off.

[0011] Preferably, the container is a crucible with a large opening area to facilitate the growth of hBN crystals on the surface of the metal solvent, and its material is one of aluminum oxide, aluminum nitride, and zirconium oxide, with a volume V of 20-200 cm 3 The material selection requirements are good thermal stability under high temperature conditions, no self-decomposition, and no reaction with experimental materials. The specific dimensions can be adjusted according to the experimental equipment used to meet the process requirements.

[0012] Preferably, the shielding gas is nitrogen (99.9%) or higher, helium, or argon, and is continuously introduced into the chamber at a flow rate of 0.02-0.04 m / min until the end of the experiment. This continuous supply of shielding gas provides a stable, inert environment for crystal growth, preventing oxygen or water vapor from contaminating the metal solvent and the reaction interface, thereby improving the crystallization quality of the hBN crystals.

[0013] Preferably, when the average diameters of the hBN powder and carbon powder used respectively meet the following requirements: 1 μm ≤ D hBN <11μm、5μm≤D C <30μm, the holding temperature and holding time should meet the following requirements: 1550℃≤T0<1575℃ and 12h≤H≤24h; when the average diameters of the hBN powder and carbon powder used meet the following requirements: 11μm≤D hBN <20μm、30μm≤D C <50μm, the holding temperature and holding time should meet any of the following conditions: 1575℃≤T0≤1600℃ and 12h≤H≤24h, or meet 1550℃≤T0<1575℃ and 24h<H≤48h. hBN powder with smaller particle size has a larger specific surface area, and only a lower holding temperature and a shorter holding time are required to completely dissolve the precursor in the metal solvent. At the same time, carbon powder with smaller particle size has a larger specific surface area and reaction activity, which can effectively reduce free oxygen atoms in the solvent at a lower temperature; for precursor hBN powder with larger particle size, its dissolution and diffusion rate is slower, so it is necessary to increase the temperature or extend the holding time to promote its dissociation into B and N atoms and enter the metal solvent.

[0014] Preferably, the cooling rate in the first stage of programmed cooling is determined by the mass fraction ratio M of Fe to Ni. Fe / M Ni OK. If 3≤M Fe / M Ni , then the cooling rate in the first stage is 3-5℃ / h, at which time the size of the prepared hBN single crystal is less than 5mm 2 ; If 1<M Fe / M Ni <3, then the cooling rate in the first stage is 1-3℃ / h, and the size of the prepared hBN single crystal is greater than 5mm 2 ; in M Fe / M Ni When fixed, the slower the cooling rate in the first stage, the larger the size of the obtained hBN single crystal.

[0015] Preferably, the cooling rate of the second stage of programmed cooling is based on the mass fraction ratio M of Fe to Ni. Fe / M Ni If the mass fraction ratio of Fe to Ni is 3≤MFe / M Ni , the cooling rate of the second stage is 2-5℃ / h; if 1≤M Fe / M Ni <3, the cooling rate of the second stage is 2-3℃ / h; Fe / M Ni When fixed, the slower the cooling rate in the second stage, the thicker the BN powder isolation layer obtained.

[0016] Preferably, since the metal solution is in a saturated temperature range (higher than T1: 1425–1450°C) in the first stage of cooling, slow cooling can promote the segregation of B atoms and N atoms in the solvent to the surface of the metal solvent, forming chain or cluster B atoms. x N y Cluster (where x and y are the number of atoms). x N y The clusters are connected to each other through dangling bonds, forming effective nucleation points. x N y The cluster further expands around the nucleation point and grows into a triangular hBN single crystal. Using a lower cooling rate helps to reduce the thermodynamic gradient of B and N atoms in the melt, reduce the density of nucleation points on the solvent surface, and allow the effective nucleation points to continue to expand, thereby increasing the size of the grown hBN crystal. In addition, since the melting point of Fe (1538℃) is higher than the melting point of Ni (1455℃), adjusting the mass fraction ratio M Fe / M Ni The size of the supersaturation temperature point T1 can be effectively controlled. At the same cooling rate, when M Fe / M Ni When the ratio of M decreases, the supersaturation temperature will decrease, the growth window of hBN crystal will increase, and the BN powder redeposition window will decrease. On the contrary, if M Fe / M Ni As M increases, the size of hBN crystals decreases and the BN powder isolation layer becomes thicker. Fe / M Ni If the ratio is less than 1, the supersaturation temperature of the solvent will be lower than its melting point, resulting in the inability to redeposit BN powder.

[0017] Preferably, the hBN single crystal is exfoliated using a hard, flaky medium (such as a blade) with a hardness greater than 50–60 HRC and a thickness between 100 and 200 μm. After 15 minutes of ultrasonic cleaning and drying at 120°C for 1 hour, the triangular hBN single crystal is removed from the surface of the metal ingot along the interface of the BN powder isolation layer below the triangular hBN single crystal. The BN powder isolation layer protects the hBN crystal from direct contact during the exfoliation process, significantly reducing mechanical damage to the hBN crystal and ensuring that the grown hBN crystal is completely exfoliated from the metal ingot surface. This results in a large-area hBN single crystal with a complete structure and considerable thickness.

[0018] Beneficial effects:

[0019] The present invention proposes a growth formula and growth method for hBN single crystals that are easy to peel off, which helps to solve the problem that hBN crystals grown by the traditional metal solvent method are difficult to separate from the metal ingot. This method uses a specific ratio of Fe-Ni-Cr ternary metal solvent to achieve the transformation of the metal solvent from a saturated state to a supersaturated state during the cooling process, inducing the formation of a redeposited BN powder isolation layer after the hBN crystal grows. This powder layer gradually accumulates under the hBN crystal during the supersaturated stage of the solvent, lifting it and separating it from the surface of the metal solvent. With the protection of the BN powder isolation layer, the operator can use a hard medium (such as a blade) to peel the hBN crystal along the isolation layer interface without direct contact with the crystal, thereby effectively avoiding mechanical damage to the hBN crystal during the peeling process. This method ensures that the grown hBN crystal can be completely peeled off from the surface of the metal ingot, ultimately obtaining a large-area hBN single crystal with a complete structure and considerable thickness.

[0020] The present invention adopts a specially designed three-stage program cooling strategy based on different formula parameters and the state of the solute in the molten metal solvent to achieve the controllable growth of hBN crystal size and powder isolation layer thickness. For example, if the required hBN single crystal size is greater than 5mm 2 , the mass fraction ratio of Fe to Ni in the formula can be controlled to be 1<M Fe / M Ni <3, and the cooling rate in the first stage is 1-3℃ / h. If the required hBN single crystal size is less than 5mm 2 , the mass fraction ratio of Fe to Ni in the formula can be controlled to be 3≤M Fe / M Ni , and the cooling rate in the first stage is 3-5℃ / h; Fe / M NiDuring fixation, slower cooling rates in the first and second stages result in larger hBN single crystals and thicker powder isolation layers. Furthermore, the addition of an appropriate amount of carbon powder to the metal solvent prevents residual oxygen from forming a metal oxide layer with the metal. This results in a more uniform distribution of nitrogen and boron on the metal ingot surface, increasing the probability of boron-nitrogen pairing and nucleation efficiency, thereby improving the growth quality of hBN crystals.

[0021] This method uses conventional industrial raw materials, and the process is compatible with traditional high-temperature reactors, demonstrating excellent reproducibility and scalability. The resulting hBN crystals are size-controlled and stable, making them suitable for high-performance applications such as deep-ultraviolet optoelectronic devices and two-dimensional heterostructures, demonstrating promising prospects for industrialization and expansion. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Exemplary embodiments are shown in the referenced drawings.The embodiments and drawings disclosed herein are to be considered illustrative rather than restrictive.

[0023] Figure 1 This is a schematic diagram of the process of Example 2 of the present invention.

[0024] Figure 2 The figure is a schematic cross-sectional view of a sample prepared using an easily peelable hBN single crystal growth formula and growth method provided by the present invention.

[0025] Figure 3 A schematic top view of a sample prepared using an easily peelable hBN single crystal growth formula and growth method provided by the present invention.

[0026] 101 is a metal ingot; 102 is a BN powder isolation layer; and 103 is a triangular hBN single crystal. DETAILED DESCRIPTION

[0027] The present invention will be further described below in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention.

[0028] In the description of the present invention, it should be understood that the terms "center", "up", "down", "front", "back", "left", "right", "top", "bottom", etc., indicating orientations or positional relationships, are 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 device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0029] Example 1:

[0030] This embodiment provides a hBN single crystal growth formula that is easy to peel, characterized in that for a container volume of V=50cm 3 The formula includes the following components: specific metal solvent material, precursor material, reducing agent material, and protective gas. Among them, the specific metal solvent material is Fe, Ni, and Cr metal elements, according to the mass fraction M Fe =54wt%, M Ni =18wt%, M Cr =28wt% of the mixture. The precursor material has a purity of not less than 99.9% and an average diameter D hBN = 5±3μm hBN powder; the reducing agent material has a purity of not less than 99.95% and an average diameter D C =15±5μm carbon powder; the protective gas is 3N (99.9%) nitrogen.

[0031] Taking the volume fraction E of a specific metal solvent material as 0.6, the formula is: 504.89×E×V=G metal ×(63.99×M Fe +56.58×M Ni +70.04×M Cr ), determine the mass G of the specific metal solvent material in the formula metal =235.38g. Since the mass of the precursor material and the mass of the specific metal solvent material satisfy the formula G metal / G hBN =30, determine the mass G of the precursor material in the formula hBN The reduction coefficient P is 0.5%, according to the formula: G c =2×P×G metal , determine the mass of the reducing agent material in the formula as G c It is 1.77g.

[0032] Example 2:

[0033] The growth process flow diagram of the hBN single crystal growth method using the easy-to-peel hBN single crystal growth formula described in Example 1 is as follows: Figure 1 As shown, the schematic diagram of the hBN single crystal that is easy to peel off is shown in Figure 2 and Figure 3 As shown, a growth method provided by the present invention for this formula includes the following specific steps: a) Use a volume V of 50 cm 3 Alumina crucibles are equipped with a sealed lid made of the same material as the container. The container and its lid must be ultrasonically cleaned for 15 minutes before use and then dried at 120°C for 6 hours. b) evenly spreading the precursor material on the bottom of the container; c) stirring the specific metal solvent material and the reducing agent material in a blender at 300 rpm for 30 minutes and then placing them in a container to form a layered structure with the precursor material below; d) After covering the container with a lid, place the filled container in a heating device cavity with controllable temperature, uniform temperature field, and good airtightness; e) Use protective gas to replace the air in the heating equipment cavity. When the residual air volume is less than one thousandth, continue to introduce protective gas at a flow rate of 0.04m / min; f) starting the heating device, raising the system temperature to 1560° C., and maintaining the temperature at this temperature for 20 hours to melt the specific metal solvent material to form a metal solution to dissolve the precursor material; g) After the end of the heat preservation, a three-stage programmed cooling strategy is used to control the crystal growth process: the first stage: slowly cooling from 1560°C to the supersaturation temperature point of 1425°C at a rate of 2°C / h, during which only a triangular hBN single crystal (103) grows; the second stage: when the temperature drops to 1425°C, the temperature is accelerated to 1350°C, the solidification point of the solution, at a rate of 4°C / h, during which a BN powder isolation layer (102) continues to grow under the hBN single crystal; the third stage: when the temperature drops to 1350°C, the temperature is rapidly cooled to 900°C at a rate of 10°C / min, the metal solution solidifies into a metal ingot (101), and then naturally cools to room temperature to complete the crystal growth process; h) After the system is cooled to room temperature, the condensed sample is taken out from the container and ultrasonically cleaned for 15 minutes using a blade having a hardness of 55 HRC and a thickness of 150 μm and dried at 120° C. for 1 hour. The triangular hBN single crystal (103) is then removed from the surface of the metal ingot (101) along the interface of the BN powder isolation layer (102) below the triangular hBN single crystal (103).

[0034] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A formula for growing hBN single crystals that is easily peelable, characterized in that: The following components are included: specific metal solvent material, precursor material, reducing agent material, and protective gas; the mass of the specific metal solvent material is G metal The material can be a Fe-Ni-Cr ternary alloy prepared in a specific mass ratio and having a purity of not less than 99.9%, or a mixture of Fe, Ni, and Cr metal elements with a purity of not less than 99.9%, wherein the mass fractions of Fe, Ni, and Cr are M and M, respectively. Fe 、M Ni 、M Cr And the following conditions are met: M Fe +M Ni +M Cr =100wt%, 60wt%<M Fe +M Ni <75wt%,32.5wt%<M Fe <75wt%; the precursor material is of mass G hBN , with a purity of not less than 99.9% and an average diameter of D hBN hBN powder, of which G hBN Satisfy 10<G metal / G hBN <40, D hBN The range is 1–20 μm and the allowable error is ±3 μm; the reducing agent material is a material with a mass of G c , purity not less than 99.95% and average diameter D C Toner, D C The range is 5-50 μm and the allowable error is ±5 μm; the protective gas is one of nitrogen, helium or argon with a concentration of 3N (99.9%) or above.

2. The easily peelable hBN single crystal growth formula according to claim 1, characterized in that: Specific mass G of the specific metal solvent material metal The volume V of the specific container (unit: cm 3 ) is determined to satisfy the formula: 504.89×E×V=G metal ×(63.99×M Fe +56.58×M Ni +70.04×M Cr ), where E is the volume fraction of the solvent material, ranging from 0.5 to 0.

7.

3. The easily peelable hBN single crystal growth formula according to claim 1, characterized in that: Specific mass G of reducing agent material carbon powder c Depends on the mass of the metal solvent material G metal , satisfying the formula: G c =2×P×G metal , where P is the reduction coefficient, ranging from 0.2% to 0.5%.

4. A method for growing an easily peelable hBN single crystal, characterized in that: The formula of the growth raw materials includes the following components: specific metal solvent material, precursor material, reducing agent material, and protective gas; the mass of the specific metal solvent material is G metal The material can be a Fe-Ni-Cr ternary alloy prepared in a specific mass ratio and having a purity of not less than 99.9%, or a mixture of Fe, Ni, and Cr metal elements with a purity of not less than 99.9%, wherein the mass fractions of Fe, Ni, and Cr are M and M, respectively. Fe 、M Ni 、M Cr And the following conditions are met: M Fe +M Ni +M Cr =100wt%, 60wt%<M Fe +M Ni <75wt%,32.5wt%<M Fe <75wt%; the precursor material is of mass G hBN , with a purity of not less than 99.9% and an average diameter of D hBN hBN powder, of which G hBN Satisfy 10<G metal / G hBN <40, D hBN The range is 1–20 μm and the allowable error is ±3 μm; the reducing agent material is a material with a mass of G c , purity not less than 99.95% and average diameter D C Toner, D C The range is 5–50 μm with an allowable error of ±5 μm; the protective gas is one of nitrogen, helium, or argon at 3N (99.9%) or higher. The method for growing an easily peelable hBN single crystal using this recipe includes the following steps: a) Use a volume V of 20–200 cm 3 A high-temperature resistant container made of alumina, aluminum nitride, or zirconium oxide, equipped with a sealed lid made of the same material. The container and lid must be ultrasonically cleaned for 15 minutes before use, then dried at 120°C for 6 hours. b) evenly spreading the precursor material on the bottom of the container; c) stirring the specific metal solvent material and the reducing agent material in a blender at 200-500 rpm for 30-60 minutes and then placing them in a container to form a layered structure with the precursor material below; d) After covering the container with a lid, place the filled container in a heating device cavity with controllable temperature, uniform temperature field, and good airtightness; e) Use protective gas to replace the air in the heating equipment cavity. When the residual air volume is less than one thousandth, continue to introduce protective gas at a flow rate of 0.02-0.04m / min; f) starting the heating device, raising the system temperature to a holding temperature T0 (1550–1600°C), and holding the temperature at this temperature for a time of H (12–48 hours) to melt the specific metal solvent material to form a metal solution to dissolve the precursor material; g) After the holding temperature is completed, a three-stage programmed cooling strategy is used to control the crystal growth process: the first stage: slowly cooling from the holding temperature T0 to the supersaturation temperature point T1 (1425-1450°C) at a rate of 1-5°C / h, during which only triangular hBN single crystals grow; the second stage: when the temperature drops to T1, the temperature is accelerated to the solidification point T2 (1300-1350°C) of the solution at a rate of 2-5°C / h, during which the BN powder isolation layer continues to grow under the hBN single crystal; the third stage: when the temperature drops to T2, the temperature is rapidly cooled to 900-1100°C at a rate of 5-20°C / min, allowing the metal solution to solidify into a metal ingot, which is then naturally cooled to room temperature, completing the crystal growth process; h) After the system is cooled to room temperature, the condensed sample is taken out from the container and the grown hBN single crystal is peeled off.

5. The method according to claim 4, characterized in that: When the average diameters of the hBN powder and carbon powder used meet the following requirements: 1μm≤D hBN <11μm、5μm≤D C <30μm, the holding temperature and holding time should meet the following requirements: 1550℃≤T0<1575℃ and 12h≤H≤24h; when the average diameters of the hBN powder and carbon powder used meet the following requirements: 11μm≤D hBN <20μm、30μm≤D C <50μm, the holding temperature and holding time shall meet any of the following conditions: 1575℃≤T0≤1600℃ and 12h≤H≤24h, or meet 1550℃≤T0<1575℃ and 24h<H≤48h.

6. The method according to claim 4, characterized in that: The cooling rate in the first stage of programmed cooling is determined by the mass fraction ratio of Fe to Ni, M Fe / M Ni OK. If 3≤M Fe / M Ni , then the cooling rate in the first stage is 3-5℃ / h; if 1<M Fe / M Ni <3, the cooling rate in the first stage is 1-3℃ / h.

7. The method according to claim 4, characterized in that: The cooling rate in the second stage of programmed cooling is determined by the mass fraction ratio M of Fe to Ni. Fe / M Ni If the mass fraction ratio of Fe to Ni is 3≤M Fe / M Ni , the cooling rate of the second stage is 2-5℃ / h; if 1≤M Fe / M Ni <3, the cooling rate of the second stage is 2-3℃ / h.

8. The method according to claim 4, wherein: The hBN single crystal exfoliation method uses a hard flaky medium (such as a blade) with a hardness greater than 50-60 HRC and a thickness between 100-200 μm. After 15 minutes of ultrasonic cleaning and 1 hour of drying at 120°C, the triangular hBN single crystal is removed from the surface of the metal ingot along the interface of the BN powder isolation layer below the triangular hBN single crystal.

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