Method for fast and uniform growth of high dielectric performance hexagonal boron nitride thin films and thin films

Abstract

This invention discloses a method and film for rapid, uniform-thickness growth of high-dielectric-performance hexagonal boron nitride (h-BN) thin films, comprising: 1) selecting a substrate; 2) placing the substrate in a plasma-assisted chemical vapor deposition (PCVD) apparatus for heating and annealing; 3) controlling the pressure of the reaction chamber of the PCVD apparatus and introducing a carrier gas and a nitrogen- or boron-containing gas into the reaction chamber; 4) controlling the pressure of the reaction chamber and raising the temperature of the reaction chamber; 5) turning on the plasma generator of the PCVD apparatus to initiate the reaction; 6) after the reaction is completed, allowing the temperature to naturally cool to room temperature to obtain a high-dielectric-performance hexagonal boron nitride thin film. This invention not only enables the rapid acquisition of large-area h-BN thin films and eliminates the wrinkles commonly found in h-BN obtained by chemical vapor deposition, but also effectively improves the dielectric properties of h-BN.

Description

Technical Field

[0001] This invention belongs to the field of hexagonal boron nitride thin film preparation, and relates to a method for preparing hexagonal boron nitride thin films, and more particularly to a method and thin film for rapid uniform thickness growth of high dielectric properties hexagonal boron nitride thin films. Background Technology

[0002] Hexagonal boron nitride (h-BN) monolayer films consist of nitrogen and boron atoms arranged alternately in a honeycomb lattice similar to graphene. Unlike graphene, which is a zero-bandgap half-metal, h-BN is a wide-bandgap insulator with a bandgap of approximately 5.9 eV. h-BN possesses excellent properties such as high thermal stability, strong chemical inertness, ultra-smooth surface, and no dangling bonds, making it an excellent insulator material in two-dimensional material systems. Van der Waals heterojunctions based on h-BN with graphene, molybdenum sulfide, etc., can effectively reduce interface electron scattering and significantly shield external interference, resulting in a qualitative improvement in device performance. In 2010, the CRDean research group first constructed a vertical heterojunction of h-BN and graphene, showing that the graphene mobility reached 60,000 cm⁻¹. 2 / Vs is an order of magnitude higher than that on silicon wafers. Since then, sandwich structures based on h-BN thin films and other two-dimensional materials have become an important means of obtaining high performance of two-dimensional materials. Furthermore, the mechanical exfoliation method is used to peel off small pieces of few-layer to single-layer h-BN from bulk h-BN to construct various heterojunctions and explore the exotic properties of different combinations of two-dimensional thin films, which has become an important research direction in the field of two-dimensional materials.

[0003] However, it's worth mentioning that large-sized h-BN bulk materials do not exist in nature. Currently, common h-BN bulk single crystals are mainly prepared under high temperature and high pressure conditions, but this method suffers from drawbacks such as low yield and small single-crystal grain size. In contrast, chemical vapor deposition (CVD) holds promise for directly growing large-sized single-layer films, enabling h-BN to enter industrial-scale production and achieve large-scale applications sooner. After years of development, h-BN growth technology has made significant progress. In recent years, h-BN growth has primarily focused on growing polycrystalline films with low grain boundary density to reduce nucleation points. Further advancements have involved utilizing the interaction forces between h-BN grains and the substrate to spontaneously align h-BN grains and then seamlessly splice them into single-crystal films, greatly improving the quality of h-BN films. In 2018, Soo Min Kim's research group grew single-crystal h-BN films on molten gold foil using CVD. In 2019, Liu Kaihui's research group crystallized copper foil, growing large-area single-crystal h-BN films. Recently, Li Lianzhong's research group grew wafer-scale h-BN single-crystal thin films by sputtering thin copper single-crystal films onto sapphire. Although large-area quasi-single-crystal or even single-crystal h-BN thin films with good properties can be prepared on metal substrates using chemical vapor deposition, the growth time is usually more than two hours, and the dielectric strength of the obtained samples is low, <0.1V / nm, which is far lower than the theoretical value of h-BN dielectric strength, and even far lower than the dielectric constant of 0.8V / nm of h-BN obtained by high temperature and high pressure. Summary of the Invention

[0004] Purpose of the invention: The technical problem to be solved by the present invention is to provide a method and a hexagonal boron nitride thin film for rapid and uniform thickness growth of high dielectric properties, which can not only rapidly obtain large-area h-BN thin films, but also eliminate wrinkles commonly found in h-BN obtained by chemical vapor deposition, and effectively improve the dielectric properties of h-BN.

[0005] Technical Solution: To solve the above-mentioned technical problems, the present invention provides a method for rapidly growing high-dielectric-performance hexagonal boron nitride thin films with uniform thickness, comprising the following steps:

[0006] 1) Select a substrate;

[0007] 2) The substrate selected in step 1) is placed in a plasma-assisted chemical vapor deposition apparatus for heating and annealing;

[0008] 3) Adjust the pressure of the reaction chamber of the plasma-assisted chemical vapor deposition device, and introduce carrier gas and nitrogen- or boron-containing gas into the reaction chamber of the plasma-assisted chemical vapor deposition device;

[0009] 4) Adjust the pressure of the reaction chamber of the plasma-assisted chemical vapor deposition (PCVD) device and increase the temperature of the reaction chamber.

[0010] 5) Turn on the plasma generator of the plasma-assisted chemical vapor deposition device to initiate the reaction;

[0011] 6) After the reaction is complete, allow it to cool naturally to room temperature to obtain a high dielectric boron nitride thin film.

[0012] Preferably, the substrate used in this invention is a non-metallic substrate or a metallic substrate; the non-metallic substrate is a silicon wafer, sapphire, silicon carbide or silicon nitride; the metallic substrate is an alloy formed from one or more of copper, nickel, platinum, iridium, ruthenium and tungsten.

[0013] Preferably, the heating and annealing time in step 2) of the present invention is 5 seconds to 5 hours; the pressure in the reaction chamber of the plasma-assisted chemical vapor deposition device in step 3) is adjusted to be no higher than 10. -4 Pa; in step 3), the carrier gas is argon, hydrogen, or nitrogen; the nitrogen- or boron-containing gas is ammonia borane, borazine, or a mixture of ammonia and borane; the gas flow rate in step 3) is 5–2000 sccm; in step 4), adjusting the reaction chamber pressure of the plasma-assisted chemical vapor deposition device involves adjusting the pressure inside the reaction chamber to 10 Pa. -5 Pa~1 atm; the temperature rise in step 4) is to raise the temperature to 50℃~1000℃; the reaction time in step 5) is 5s~3600s.

[0014] Preferably, in step 2) of the present invention, the heating and annealing time is 30 min to 2 h; in step 3), the gas flow rate is 100 sccm to 500 sccm; and in step 4), the pressure of the reaction chamber of the plasma-assisted chemical vapor deposition device is adjusted to 10 sccm. -2 Pa~10 2 Pa; the temperature rise in step 4) is to raise the temperature to 600℃~800℃; the reaction time in step 5) is 300s~1200s.

[0015] Preferably, the plasma generator used in this invention is a high-frequency plasma generator, a low-pressure plasma generator, or an arc plasma generator; the power of the plasma generator is 5W to 300W; and the pressure in the reaction chamber of the plasma-assisted chemical vapor deposition apparatus is 10... -1 Pa~1atm; the heating temperature of the reaction chamber in the plasma-assisted chemical vapor deposition apparatus is 20℃~1000℃.

[0016] Preferably, the plasma generator used in this invention has a power of 10W-50W.

[0017] A hexagonal boron nitride thin film prepared by a method for rapid, uniform-thickness growth of high-dielectric-performance hexagonal boron nitride thin films as described above, wherein the hexagonal boron nitride thin film is a high-dielectric-performance hexagonal boron nitride thin film, especially a wafer-level high-dielectric-performance hexagonal boron nitride thin film.

[0018] Preferably, the diameter of the hexagonal boron nitride film obtained by the present invention is 1 μm to 1000 cm, more preferably 0.5 cm to 5 cm; the surface of the hexagonal boron nitride film is smooth and wrinkle-free; the hexagonal boron nitride film has a diameter of 100 μm. 2 Within the specified range, the undulation height is no higher than 2nm; the thickness of the hexagonal boron nitride film is 1nm to 10nm.

[0019] The principle of this invention is to rapidly fabricate wafer-level high-dielectric-performance h-BN thin films on various substrates such as copper foil, copper-nickel alloy, iron foil, nickel foil, and sapphire using a proton-assisted method by precisely controlling the growth temperature, plasma power, and plasma interaction time. Wafer-level high-dielectric-performance h-BN thin films refer to thin films with high breakdown field strength and a diameter of 1–4 inches. The wafer-level high-dielectric-performance h-BN thin film of this invention can reach a diameter of 2 inches, and its dielectric performance (breakdown field strength) can reach 10 MV / cm.

[0020] Beneficial Effects: Compared with existing technologies, this invention has the following advantages: The proton-assisted method used in this invention significantly improves the quality of h-BN, resulting in a smooth surface, good insulation properties, and high dielectric strength. By adjusting the growth temperature, time, plasma power, and plasma treatment time, this invention can rapidly grow wafer-level h-BN films with controllable thickness, greatly saving growth time and improving production efficiency. This invention is a universal method applicable to various metals and insulating substrates such as copper, iron, nickel, platinum, iridium, ruthenium, tungsten, silicon wafers, sapphire, silicon carbide, and glass. By using a proton-assisted method at lower temperatures and through precise control of the growth temperature and plasma power, this invention can rapidly grow high-dielectric-performance h-BN films on various substrates at lower temperatures, eliminating the wrinkles commonly found in h-BN samples obtained by conventional chemical vapor deposition methods. This significantly improves the dielectric strength of the h-BN film, even exceeding that of peeled h-BN samples. Furthermore, the sample growth time is short, the thickness is precisely controllable, and the size can reach the wafer level. h-BN thin films exhibit excellent insulation properties, and their thickness and number of layers can be precisely controlled, achieving wafer-level dimensions. This invention provides sample preparation technology support for the application of h-BN in future functional thin films and micro / nano optoelectronic devices. This invention provides sample preparation technology support for improving the performance of various two-dimensional thin film heterojunctions and realizing the application of high-dielectric-performance h-BN in future functional thin films and micro / nano optoelectronic devices, laying an important foundation for the early industrial production of h-BN and promoting social progress. Attached Figure Description

[0021] Figure 1 This refers to h-BN prepared on a copper-nickel substrate in Example 3;

[0022] Figure 2 This is a diagram showing the results of the equal-thickness growth of h-BN prepared in Example 3;

[0023] Figure 3 These are atomic force microscope images of the hBN crystals prepared in Example 3;

[0024] Figure 4 yes Figure 3 Optical images of thin films grown from medium-sized grains. Detailed Implementation

[0025] The plasma-assisted chemical vapor deposition apparatus in this embodiment was purchased from Hefei Kejing Materials Technology Co., Ltd., product model No. SP20181101.

[0026] Example 1

[0027] High dielectric strength h-BN was grown on a copper substrate using a plasma-assisted chemical vapor deposition (PECVD) method. Specifically, a 1 μm thick copper substrate was first fabricated on a sapphire substrate using magnetron sputtering, followed by annealing at 1000°C for 40 min in a high-temperature furnace to achieve a smooth surface. The smoothed copper substrate was then placed on a tray within a PECVD apparatus, and the reaction chamber pressure was allowed to decrease to less than 10 °C. -4 To minimize water and oxygen levels in the reaction chamber, hydrogen, argon, and boron- and nitrogen-containing ammonia borane vapor were introduced, specifically 200 sccm of hydrogen and 20 sccm of argon. The ammonia borane solid source heating temperature was set to 70°C, and the reaction chamber pressure was stabilized at 1 Torr using a pressure regulating valve. Heating was initiated for 25 minutes, increasing the temperature to 800°C, and then maintained for 10 minutes to ensure substrate thermal uniformity. The inductively coupled plasma generator was then activated at 40W, and a 1 nm high-dielectric-strength h-BN film was grown for 600 seconds. After growth, heating and the ammonia borane channel were shut off, and the film was allowed to cool naturally to 400°C. The hydrogen and argon gas supply was then turned off, and the film was finally cooled to room temperature before removal.

[0028] The prepared samples were observed using an optical microscope to check the surface uniformity and an atomic force microscope to check the surface roughness and other details. After transfer, Raman spectroscopy was used to determine the crystal quality of h-BN.

[0029] Example 2

[0030] High-dielectric-strength h-BN was grown on a nickel substrate using plasma-assisted chemical vapor deposition (PECVD). Specifically, a 500 nm thick nickel substrate was first fabricated on a sapphire substrate using magnetron sputtering, followed by annealing at 1000°C for 40 min in a high-temperature furnace to achieve a smooth surface. The smoothed substrate was then placed on a tray within the PECVD apparatus, and the reaction chamber pressure was allowed to drop below 10 °C. -4 To minimize water and oxygen levels in the reaction chamber, hydrogen, argon, and boron- and nitrogen-containing ammonia borane vapor were introduced, specifically 200 sccm of hydrogen and 20 sccm of argon. The ammonia borane solid source heating temperature was set to 70°C, and the reaction chamber pressure was stabilized at 1 torr using a pressure regulating valve. Heating was initiated for 25 minutes, increasing the temperature to 800°C, and then maintained for 10 minutes to ensure substrate thermal uniformity. An inductively coupled plasma generator (ICP-P) with a power of 40W was activated. The occupancy ratio of the h-BN film was controlled by adjusting the plasma time; 8 layers (approximately 4 nm) of h-BN film were obtained after 1200 seconds of growth. After growth, heating and the ammonia borane channel were shut off, and the film was allowed to cool naturally to 400°C. Hydrogen and argon gas were then turned off, and the film was finally cooled to room temperature before removal.

[0031] The prepared samples were observed using an optical microscope to check the surface uniformity and an atomic force microscope to check the surface roughness and other details. After transfer, Raman spectroscopy was used to determine the crystal quality of h-BN.

[0032] Example 3

[0033] High dielectric strength h-BN was grown on a copper-nickel substrate using plasma-assisted chemical vapor deposition (PCVD). Specifically, a 1 μm thick copper-nickel substrate was first fabricated on a sapphire substrate using magnetron sputtering, followed by annealing at 1000°C for 40 min in a high-temperature furnace to achieve a smooth surface. The smoothed substrate was then placed on a tray within the PCVD apparatus, and the reaction chamber pressure was allowed to drop below 10 °C. -4 To minimize water and oxygen levels in the reaction chamber, hydrogen, argon, and boron- and nitrogen-containing ammonia borane vapor were introduced, specifically 200 sccm of hydrogen and 20 sccm of argon. The ammonia borane solid source heating temperature was set to 70°C, and the reaction chamber pressure was stabilized at 1 torr using a pressure regulating valve. Heating was initiated for 25 minutes, increasing the temperature to 800°C, and then maintained for 10 minutes to ensure substrate thermal uniformity. The inductively coupled plasma generator was then activated at 20W, and growth was completed in 600 seconds to obtain a 1.5 nm thick high-dielectric-strength h-BN film. After growth, heating and the ammonia borane channel were shut off, and the film was allowed to cool naturally. Once the temperature dropped to 400°C, the hydrogen and argon gas supply was turned off, and the film was finally cooled to room temperature before removal.

[0034] The prepared samples were observed using an optical microscope to check the surface uniformity and an atomic force microscope to check the surface roughness and other details. After transfer, Raman spectroscopy was used to determine the crystal quality of h-BN.

[0035] like Figure 1 The image shows h-BN prepared on a copper-nickel substrate using the method provided in this embodiment. Figure 1 a is an hBN thin film sample with a diameter of 2 inches. The sample is clean and free of contaminants on a large scale. Figure 1 b is an atomic force microscope image of h-BN grown on copper-nickel at a depth of 10 micrometers. In any small area, the sample surface is atomically smooth and has a clear surface. Figure 1 c is an atomic force microscope image of the hBN thin film sample transferred to a silicon wafer, showing that the film is wrinkle-free, clean, and uniform. Figure 1 d is the height curve of the thin film in Figure c; Figure 1 e represents the Raman curves of the hBN thin film at three random locations, with the characteristic peak at 1370 cm⁻¹. -1 ; Figure 1 f is the breakdown test of the hBN thin film, showing a breakdown field strength of 10MV / cm, indicating excellent dielectric properties.

[0036] For the conventional CVD process and the uniform thickness growth process and results of the thin film prepared in this embodiment, please refer to [link / reference]. Figure 2 ,in, Figure 2 This is a schematic diagram of uniform thickness growth. In traditional thermal CVD processes, due to surface-constrained growth strategies, monolayer hBN is typically obtained on a Cu(111) substrate (left). In this embodiment, hBN grains of different thicknesses (middle) are prepared by proton-assisted control of the formation of hBN precursor clusters (BxNyHz) of different thicknesses, and further seamlessly connected to form a uniform multilayer hBN film (right).

[0037] To this end, we set the heating temperature of the raw material ammonia borane solid source to 68℃, 70℃, 72℃, 74℃, 77℃, 80℃, 82℃, and 84℃ to control the grain size and film thickness. The results are shown in [reference needed]. Figure 3 and Figure 4 . Figure 3 These are atomic force microscope images of hBN grains prepared at different raw material temperatures in this embodiment. The height distribution is shown along the corresponding dotted lines in the image. The height of the hBN grains grown at different raw material temperatures is uniform, and they all achieve equal thickness growth, with heights of approximately 0.9 nm, 1.4 nm, 1.9 nm, 2.4 nm, 2.8 nm, 3.2 nm, 3.7 nm, and 4.2 nm, respectively. Figure 4 yes Figure 3 Thin films grown from medium-sized grains, including corresponding optical images and thickness curves, were shown. The film thicknesses were 0.9 nm, 1.4 nm, 1.9 nm, 2.4 nm, 2.8 nm, 3.2 nm, 3.7 nm, and 4.2 nm, respectively, controlled by the corresponding raw material temperatures: 68℃, 70℃, 72℃, 74℃, 77℃, 80℃, 82℃, and 84℃. Therefore, we can obtain films of corresponding thicknesses by controlling the raw material temperature, and each film is grown uniformly and with equal thickness.

[0038] Example 4

[0039] High dielectric strength h-BN is grown on a silicon substrate using plasma-assisted chemical vapor deposition (PECVD). Specifically, the silicon wafer surface is first treated with nitrogen plasma to ensure cleanliness. The wafer is then placed on a tray within the PECVD apparatus, and the reaction chamber pressure is allowed to drop below 10 °C. -4To minimize water and oxygen levels in the reaction chamber, hydrogen, argon, and boron- and nitrogen-containing ammonia borane vapor were introduced, specifically 200 sccm of hydrogen and 20 sccm of argon. The ammonia borane solid source heating temperature was set to 70°C, and the reaction chamber pressure was stabilized at 1 torr using a pressure regulating valve. Heating was initiated for 25 minutes, increasing the temperature to 600°C, and then maintained for 10 minutes to ensure substrate thermal uniformity. The inductively coupled plasma generator was then activated at 50W, and a 3 nm thick h-BN film was grown for 600 seconds. After growth, heating and the ammonia borane channel were shut off, and the film was allowed to cool naturally. Once the temperature dropped to 400°C, the hydrogen and argon gas supply was turned off, and the film was finally cooled to room temperature before removal.

[0040] The prepared samples were observed using an optical microscope to check the surface uniformity and an atomic force microscope to check the surface roughness and other details. After transfer, Raman spectroscopy was used to determine the crystal quality of h-BN.

[0041] Example 5

[0042] High dielectric strength h-BN was grown on a sapphire substrate using plasma-assisted chemical vapor deposition (PECVD). Specifically, the sapphire substrate surface was first treated with nitrogen plasma to ensure cleanliness. The sapphire substrate was then placed on a tray within the PECVD apparatus, and the reaction chamber pressure was allowed to drop below 10 °C. -4 To minimize water and oxygen levels in the reaction chamber, hydrogen, argon, and boron- and nitrogen-containing ammonia borane vapor were introduced, specifically 200 sccm of hydrogen and 20 sccm of argon. The ammonia borane solid source heating temperature was set to 70°C, and the reaction chamber pressure was stabilized at 1 torr using a pressure regulating valve. Heating was initiated for 25 minutes, increasing the temperature to 600°C, and then maintained for 10 minutes to ensure substrate thermal uniformity. The inductively coupled plasma generator was then activated at 50W, and a 3 nm thick h-BN film was grown for 600 seconds. After growth, heating and the ammonia borane channel were shut off, and the film was allowed to cool naturally. Once the temperature dropped to 400°C, the hydrogen and argon gas supply was turned off, and the film was finally cooled to room temperature before removal.

[0043] The prepared samples were observed using an optical microscope to check the surface uniformity and an atomic force microscope to check the surface roughness and other details. After transfer, Raman spectroscopy was used to determine the crystal quality of h-BN.

[0044] Example 6

[0045] The difference from Example 4 is that:

[0046] High dielectric strength h-BN is grown on a silicon substrate using plasma-assisted chemical vapor deposition (PECVD). Specifically, the silicon wafer surface is first treated with nitrogen plasma to ensure cleanliness. The wafer is then placed on a tray within the PECVD apparatus, and the reaction chamber pressure is allowed to drop below 10 °C. -4To minimize water and oxygen levels in the reaction chamber, hydrogen, argon, and boron- and nitrogen-containing ammonia borane vapor were introduced, specifically 200 sccm of hydrogen and 20 sccm of argon. The ammonia borane solid source heating temperature was set to 75°C, and the reaction chamber pressure was stabilized at 1 torr using a pressure regulating valve. Heating was initiated for 25 minutes, increasing the temperature to 600°C, and then maintained for 10 minutes to ensure substrate thermal uniformity. The inductively coupled plasma generator was then activated at a power of 50W. The occupancy ratio of the h-BN film was controlled by adjusting the plasma time, and a 10 nm thick h-BN film was grown for 600 seconds. After growth, heating and the ammonia borane channel were shut off, and the film was allowed to cool naturally. Once the temperature dropped to 400°C, the hydrogen and argon gases were turned off, and the film was finally cooled to room temperature and removed.

[0047] The prepared samples were observed using an optical microscope to check the surface uniformity and an atomic force microscope to check the surface roughness and other details. After transfer, Raman spectroscopy was used to determine the crystal quality of h-BN.

[0048] Example 7

[0049] High dielectric strength h-BN was grown on a copper-nickel substrate using borazine as a raw material via plasma-assisted chemical vapor deposition. Specifically, a 1 μm thick copper-nickel substrate was first prepared on a sapphire substrate using magnetron sputtering, followed by annealing at 1000°C for 40 min in a high-temperature furnace to achieve a smooth substrate surface. The smoothed substrate was then placed on a tray within the plasma-assisted chemical vapor deposition apparatus, and the reaction chamber pressure was allowed to drop below 10 °C. -4 To minimize water and oxygen levels in the reaction chamber, hydrogen, borazine, and argon were introduced, specifically 200 sccm of hydrogen, 1°C of borazine, and 20 sccm of argon. The pressure in the reaction chamber was stabilized at 1 torr using a pressure regulating valve. Heating was initiated for 25 minutes to reach 800°C, then maintained for 10 minutes to ensure substrate thermal uniformity. The inductively coupled plasma generator was then activated at 20W, and growth was completed in 600 seconds to obtain a 1.5 nm thick high-dielectric-strength h-BN film. After growth, heating and the borazine channel were shut off, and the film was allowed to cool naturally to 400°C. Hydrogen and argon were then turned off, and the film was finally cooled to room temperature before removal.

[0050] The prepared samples were observed using an optical microscope to check the surface uniformity and an atomic force microscope to check the surface roughness and other details. After transfer, Raman spectroscopy was used to determine the crystal quality of h-BN.

[0051] Example 8

[0052] High dielectric strength h-BN was grown on a copper-nickel substrate using ammonia and borane as raw materials via plasma-assisted chemical vapor deposition. Specifically, a 1 μm thick copper-nickel substrate was first prepared on a sapphire substrate by magnetron sputtering, followed by annealing at 1000°C for 40 min in a high-temperature furnace to achieve a smooth surface. The smoothed substrate was then placed on a tray within the plasma-assisted chemical vapor deposition apparatus, and the reaction chamber pressure was allowed to drop below 10 °C. -4 To minimize water and oxygen levels in the reaction chamber, hydrogen, ammonia, borane, and argon were introduced, specifically 200 sccm for hydrogen, 10 sccm for ammonia, 5 sccm for borane, and 20 sccm for argon. The pressure in the reaction chamber was stabilized at 1 torr using a pressure regulating valve. Heating was initiated for 25 minutes to reach 800°C, then maintained for 10 minutes to ensure substrate thermal uniformity. An inductively coupled plasma generator (ICP-P) with a power of 20W was activated. The occupancy ratio of the h-BN film was controlled by adjusting the plasma time. A 1.5 nm thick high-dielectric-strength h-BN film was grown for 600 seconds. After growth, heating and the ammonia and borane channels were shut off, and the film was allowed to cool naturally. Once the temperature dropped to 400°C, the hydrogen and argon gases were turned off, and the film was finally cooled to room temperature and removed.

[0053] The prepared samples were observed using an optical microscope to check the surface uniformity and an atomic force microscope to check the surface roughness and other details. After transfer, Raman spectroscopy was used to determine the crystal quality of h-BN.

[0054] The results obtained based on the foregoing embodiments are shown in Table 1.

[0055] Table 1 shows the results of Examples 1-8.

[0056]

[0057] As shown in Table 1, in Examples 1-3, copper's catalytic ability on the raw materials is weaker than that of nickel, while nickel's adsorption capacity for raw materials is too strong, leading to a decrease in film crystallinity. Therefore, a copper-nickel alloy substrate was used, combining the advantages of both metals, resulting in high film crystallinity and a flatness of 0.3 nm, approaching the limit of atomic force microscopy testing precision. Furthermore, Example 3 exhibits dielectric breakdown performance close to that of mechanically exfoliated bulk hBN films, reaching the order of 10 MV / cm, far exceeding the dielectric breakdown performance of other examples. In Examples 4-6, the silicon wafer and sapphire substrate have no catalytic effect on the raw materials, so the resulting film crystallinity decreases slightly, and the breakdown strength decreases accordingly. However, its advantage is that no subsequent transfer process is required, and it can be directly characterized and used. The raw materials used in Examples 7-8 are flammable and explosive, requiring high precision in the growth process.

Claims

1. A method for rapidly growing high-dielectric-performance hexagonal boron nitride thin films with uniform thickness, comprising the following steps: 1) Select a substrate; the substrate is a non-metallic substrate or a metallic substrate; the non-metallic substrate is a silicon wafer, sapphire, silicon carbide or silicon nitride; the metallic substrate is an alloy formed from one or more of copper, nickel, platinum, iridium, ruthenium and tungsten; 2) The substrate selected in step 1) is placed in a plasma-assisted chemical vapor deposition apparatus for heating and annealing; the heating and annealing time is 5s to 5h. 3) Adjust the reaction chamber pressure of the plasma-assisted chemical vapor deposition device to no higher than 10. -4 Pa, and a carrier gas and a reaction gas are introduced into the reaction chamber of the plasma-assisted chemical vapor deposition apparatus; the carrier gas includes argon, hydrogen or nitrogen; the reaction gas is ammonia borane, borazine or a mixture of ammonia and borane; the gas flow rate is 100 sccm to 500 sccm; 4) Adjust the reaction chamber pressure of the plasma-assisted chemical vapor deposition device to 10. -2 Pa~10 2 Pa, the reaction chamber of the plasma-assisted chemical vapor deposition device is heated to 600℃~800℃; 5) Turn on the plasma generator of the plasma-assisted chemical vapor deposition device to initiate the reaction; the reaction time is 300s~1200s; the plasma generator is a high-frequency plasma generator, a low-pressure plasma generator, or an arc plasma generator; the power of the plasma generator is 5W~300W; 6) After the reaction is complete, allow it to cool naturally to room temperature to obtain a high dielectric boron nitride thin film.

2. The method for rapid, uniform-thickness growth of high-dielectric-performance hexagonal boron nitride thin films according to claim 1, characterized in that: The power of the plasma generator is 10W-50W.

3. A hexagonal boron nitride thin film prepared by the method for rapid uniform thickness growth of high dielectric boron nitride thin films as described in any one of claims 1-2; wherein the hexagonal boron nitride thin film is a high dielectric boron nitride thin film.

4. The hexagonal boron nitride thin film according to claim 3, characterized in that: The hexagonal boron nitride thin film is a wafer-level high-dielectric-performance hexagonal boron nitride thin film, with a vertical breakdown field strength reaching 5MV / cm, 8MV / cm or 10MV / cm.

5. The hexagonal boron nitride thin film according to claim 3 or 4, characterized in that: The diameter of the hexagonal boron nitride film is 1 μm to 1000 cm, and the surface of the hexagonal boron nitride film is smooth and wrinkle-free; the thickness of the hexagonal boron nitride film is 1 nm to 10 nm.

6. The hexagonal boron nitride thin film according to claim 5, characterized in that: The diameter of the hexagonal boron nitride thin film is 0.5cm to 5cm.

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