Method for remote epitaxial growth of nitride film on silicon substrate, nitride film and semiconductor device

Abstract

The invention discloses a method for remote epitaxial growth of a nitride film on a silicon substrate, the nitride film and a semiconductor device.The method comprises the following steps that surface nitriding treatment is conducted on the silicon substrate, so that a Si3N4 layer is formed on the surface of the silicon substrate; a single-layer graphene layer is formed on the surface of the side, provided with the Si3N4 layer, of the silicon substrate; performing remote epitaxial growth of a nitride film on the single-layer graphene layer; wherein the lattice information of the nitride film is the same as the lattice structure information of the Si3N4 layer. By adopting the technical scheme provided by the invention, remote epitaxial growth of the nitride film on the silicon substrate can be realized.

Description

Technical Field

[0001] The present invention relates to the technical field of remote epitaxy and third-generation semiconductor materials, and in particular to a method for remote epitaxially growing a nitride film on a silicon substrate, a nitride film prepared by the method, and a semiconductor device comprising the nitride film. Background Art

[0002] In recent years, two-dimensional (2D) materials, especially heterogeneous integration of graphene and nitride, have broad application prospects in the preparation of flexible wearable devices and transferable electronic and photonic devices. Recently, a new epitaxial technology, remote epitaxy, uses the "lattice transparency" of graphene to produce remote electrostatic interactions between the substrate and the epitaxial layer. With this interaction, the epitaxial layer can "copy" the lattice information of the substrate through graphene, thereby ensuring the consistency of the lattice orientation of the epitaxial layer. This method can not only alleviate the lattice mismatch caused by the substrate, but also the good thermal conductivity of graphene can alleviate the thermal mismatch between the epitaxial layer and the substrate, thereby preparing high-quality single-crystalline nitride films. However, the silicon substrate itself does not have spontaneous polarization and the surface potential fluctuation is not large, resulting in the surface potential of the silicon substrate cannot penetrate the two-dimensional material, and the charge on the surface of the two-dimensional material cannot be redistributed, so it is impossible to achieve the epitaxy of nitride epitaxial layers with the same lattice information as the substrate on the two-dimensional material. At the same time, the large lattice mismatch also makes it difficult to epitaxially grow high-quality nitride films. Summary of the invention

[0003] In view of this, one of the objects of the present invention is to provide a method for remote epitaxial growth of nitride films on silicon substrates, by means of surface nitridation treatment, so that silicon substrates that cannot be remotely epitaxially grown have the ability of remote epitaxy, and then remote epitaxially grow nitride films.

[0004] A method for remote epitaxial growth of a nitride film on a silicon substrate comprises the following steps: Performing a surface nitridation treatment on the silicon substrate to form a Si3N4 layer on the surface of the silicon substrate; Forming a single-layer graphene layer on a surface of the silicon substrate having the Si3N4 layer; remote epitaxially growing a nitride film on the single-layer graphene layer; The lattice information of the nitride film is the same as the lattice structure information of the Si3N4 layer.

[0005] Preferably, the crystal structures of the nitride film and the Si3N4 layer are both hexagonal, more preferably hexagonal wurtzite structure.

[0006] According to some preferred implementation aspects of the present invention, the surface nitridation treatment comprises the following steps: Placing the silicon substrate in a MBE (Molecular beam epitaxy) vacuum chamber, setting the temperature to 420-550° C., and introducing nitrogen gas with a flow rate of 0.9-1.8 sccm into the MBE vacuum chamber; wherein the duration of the nitrogen gas is 4-7 min; Treating the silicon substrate with nitrogen-containing plasma at a power of 220-370 W for 10-24 min; After the temperature in the vacuum chamber drops to room temperature, the silicon substrate after nitridation is taken out; wherein, the silicon substrate after nitridation has a Si3N4 layer on at least one side of the surface. The currently disclosed surface nitridation process is only used to remove surface impurities or adsorbed oxygen, water molecules, etc., and repair lattice defects such as nitrogen vacancies, etc., while the surface treatment process of the present invention has a higher processing power and a longer time, and the purpose is to form a Si3N4 layer on at least one side of the surface of the silicon substrate.

[0007] According to some preferred implementation aspects of the present invention, the material of the nitride film is gallium nitride, and the remote epitaxial growth of the nitride film comprises the following steps: At a temperature of 600-800° C., a nitrogen source with a flow rate of 8000-14000 sccm, a gallium source with a flow rate of 30-80 sccm, and a carrier gas are introduced for a reaction of 5-30 minutes to grow a nucleation layer; Under the condition of a temperature of 1000-1200° C., a nitrogen source with a flow rate of 5000-8000 sccm, a gallium source with a flow rate of 30-90 sccm, and a carrier gas are introduced, and the reaction is carried out for 150-200 min to grow a thin film layer on the nucleation layer to obtain the nitride thin film; Wherein, the carrier gas includes nitrogen with a flow rate of 400 sccm-600 sccm and hydrogen with a flow rate of 40 sccm-60 sccm.

[0008] According to some preferred implementation aspects of the present invention, the material of the nitride film is aluminum nitride, and the remote epitaxial growth of the nitride film comprises the following steps: Under the condition of temperature of 800-1100° C., a nitrogen source with a flow rate of 8000-14000 sccm, an aluminum source with a flow rate of 30-80 sccm and a carrier gas are introduced, and the reaction is carried out for 5-30 minutes to grow a nucleation layer; Under the condition of temperature of 1200-1400° C., introducing a nitrogen source with a flow rate of 5000-8000 sccm, an aluminum source with a flow rate of 30-90 sccm and a carrier gas, reacting for 150-200 min to grow a thin film layer on the nucleation layer to obtain the nitride thin film; Wherein, the carrier gas includes nitrogen with a flow rate of 400 sccm-600 sccm and hydrogen with a flow rate of 40 sccm-60 sccm.

[0009] According to some preferred implementation aspects of the present invention, the silicon substrate is a single crystal silicon substrate with a (100) plane; And / or, before the surface nitridation treatment of the silicon substrate is performed, the following steps are included: Cleaning the surface of the silicon substrate; The cleaned silicon substrate is placed in an MBE vacuum chamber, argon gas is introduced into the MBE vacuum chamber, and the oxide layer on the surface of the cleaned silicon substrate is etched by the argon gas. After the argon etching is completed, the temperature is raised and annealed to repair the surface lattice. That is, the present invention performs argon etching in the MBE vacuum chamber to etch away the oxide layer on the surface of the cleaned silicon substrate, and then anneals the surface to flatten it and repair the lattice, so that the surface flatness of the silicon substrate is further improved.

[0010] According to some preferred implementation aspects of the present invention, the process conditions of the argon etching include a pressure of 4.5-5.5×10 6 torr, temperature of 380-420°C, filament current of 7-9 mA, high voltage energy of 480-520 eV and treatment time of 10-20 min.

[0011] According to some preferred implementation aspects of the present invention, the single-layer graphene layer is grown and covered on the silicon substrate by the following steps: A single-layer graphene layer is grown on the copper foil; the single-layer graphene layer is peeled off from the copper foil and covered on the surface of one side of the silicon substrate having the Si3N4 layer by wet transfer.

[0012] According to some preferred implementation aspects of the present invention, the single-layer graphene layer is grown by the following steps: The copper foil is placed in a quartz tube furnace at a temperature of 1000-1200° C., hydrogen gas with a flow rate of 10-15 sccm is introduced into the quartz tube furnace, and annealing is performed for 10-25 minutes; Under the condition of a pressure of 1-3 torr, methane with a flow rate of 5-10 sccm and hydrogen with a flow rate of 50-100 sccm are introduced into the quartz tube furnace for 20-30 minutes to grow the single-layer graphene layer on the copper foil.

[0013] In some embodiments of the present invention, the method for remote epitaxial growth of a nitride film on a silicon substrate specifically comprises the following steps: Cleaning the surface of the silicon substrate; Placing the cleaned silicon substrate in an MBE vacuum chamber, introducing argon gas into the MBE vacuum chamber, and etching the oxide layer on the surface of the cleaned silicon substrate using the argon gas; Performing a surface nitridation treatment on the silicon substrate in the MBE vacuum chamber to form a Si3N4 layer on the surface of the silicon substrate; Growing a single graphene layer on copper foil; The single-layer graphene layer is peeled off from the copper foil, and covered on the surface of the silicon substrate having the Si3N4 layer by wet transfer to form a single-layer graphene / Si3N4 / Si structure; A nitride thin film is remotely epitaxially grown on the single-layer graphene layer.

[0014] The present invention also provides a nitride film prepared by the above method and a semiconductor device including the nitride film.

[0015] Due to the application of the above technical scheme, the present invention has the following advantages compared with the prior art: the present invention provides a method for remote epitaxial growth of a nitride film on a silicon substrate, wherein a silicon substrate without charge transfer and spontaneous polarization is treated by surface nitridation treatment to form a Si3N4 layer on the surface of the silicon substrate; then a single-layer graphene layer is transferred to the side of the silicon substrate having the Si3N4 layer; and then a remote epitaxial method is used to remotely epitaxially grow a nitride film on the single-layer graphene layer, thereby realizing remote epitaxial growth of a nitride film on a silicon substrate, overcoming the defect that the prior art cannot remotely epitaxially grow a nitride film on a silicon substrate; in addition, by growing a nitride film on a silicon substrate by remote epitaxy, the lattice structure information of the epitaxially grown nitride film is achieved to be the same as the lattice structure information of the Si3N4 layer on the surface of the silicon substrate, which can alleviate the large lattice mismatch and thermal mismatch existing when epitaxially growing a nitride film on a silicon substrate, and can obtain a high-quality nitride film based on a silicon substrate. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0017] Figure 1 is a flow chart of the steps of a method for remote epitaxial growth of a nitride film on a silicon substrate according to a preferred embodiment of the present invention; Figure 2 It is a growth schematic diagram of a method for remote epitaxial growth of a nitride film on a silicon substrate according to a preferred embodiment of the present invention; FIG3 (a) is an AFM (Atomic Force Microscope) photograph of a silicon substrate before surface argon etching in a preferred embodiment of the present invention; FIG3 (b) is an AFM photograph of a silicon substrate after surface argon etching in a preferred embodiment of the present invention; Figure 4 It is an atomic structure diagram and a charge density contour diagram before and after the substrate nitridation treatment in a preferred embodiment of the present invention. DETAILED DESCRIPTION

[0018] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0019] Patent CN201810714565.4 discloses a method for growing a single-crystal gallium nitride film on a Si(100) substrate, comprising: forming an amorphous SiO2 layer on a Si(100) substrate; transferring single-crystal graphene to a Si(100) / SiO2 substrate; pretreating the surface of the single-crystal graphene to produce dangling bonds; growing an AlN nucleation layer; and epitaxially growing a GaN film. However, this patent still has the problem of weak graphene dangling bonds, the quality of the epitaxial layer grown by van der Waals epitaxy is worse than that of the remote epitaxy scheme, and the AlN buffer layer and the GaN film cannot be separated when the epitaxial layer is stripped, and the film composition is complex.

[0020] For example, patent CN202310515409.6 discloses a method for epitaxially growing nitride materials on graphene using silicon nitride as a mask layer. The method comprises the following steps: selecting a single crystal substrate, transferring or growing multilayer graphene on the single crystal substrate, forming a porous silicon nitride mask layer on the graphene, and epitaxially growing nitride materials at the window. However, the patent uses silicon nitride as a mask layer, which cannot reduce the stress generated during lateral epitaxy. Compared with the growth mode of remote epitaxy on a single layer of graphene, the epitaxial layer stress is higher, and peeling transfer cannot be achieved, which is not conducive to subsequent research such as the preparation of flexible devices.

[0021] Based on this, the present invention provides a method for remote epitaxial growth of nitride films on silicon substrates, using plasma (such as nitrogen) to treat the surface of the silicon substrate to obtain a Si3N4 layer on the surface of the silicon substrate, breaking the state of no potential fluctuation on the surface of the original silicon substrate, and then transferring a two-dimensional material layer (i.e., a single-layer graphene layer) to alleviate the large lattice mismatch and thermal mismatch of the nitride film to improve the quality of the nitride film, which can be applied in the field of CMOS integration; and then using MOCVD (Metal-organicChemical Vapor Deposition, metal organic compound chemical vapor deposition) to remotely epitaxially grow high-quality nitride films (such as gallium nitride or aluminum nitride, etc.) on the single-layer graphene layer. For details, please refer to Figure 1 and Figure 2 The method for remote epitaxial growth of a nitride film on a silicon substrate provided by the present invention comprises the following steps: S1: Prepare silicon substrate.

[0022] The silicon substrate in the present invention is a single crystal silicon substrate with a (100) plane.

[0023] S2: performing surface treatment on the silicon substrate.

[0024] Surface treatment specifically includes the following steps: S21: cleaning the surface of the silicon substrate.

[0025] The silicon substrate is organically cleaned. Specifically, the silicon substrate is first ultrasonically cleaned in an acetone solution for 5-10 minutes, then ultrasonically cleaned in an isopropanol solution for 5-10 minutes, and finally ultrasonically cleaned in water for 5-10 minutes.

[0026] S22: placing the cleaned silicon substrate in an MBE vacuum chamber, introducing argon gas into the MBE vacuum chamber, and etching the oxide layer on the surface of the cleaned silicon substrate using the argon gas.

[0027] The material of the oxide layer is SiO2. The cleaned silicon substrate can be etched by argon etching. The process conditions of argon etching include a pressure of 4.5-5.5×10 6 torr, temperature of 380-420°C, filament current of 7-9 mA, high voltage energy of 480-520 eV and treatment time of 10-20 min.

[0028] Furthermore, after the argon etching is completed, the temperature in the MBE vacuum chamber can be raised to 500-650°C, and the silicon substrate can be annealed for 25-35 minutes to repair the surface lattice of the silicon substrate. That is, the present invention performs argon etching in the MBE vacuum chamber to etch away the surface oxide layer, and then anneals the surface to flatten it and repair the lattice, so that the surface flatness of the silicon substrate is further improved.

[0029] After the above treatment, N-Plasma etching is directly performed in the MBE chamber.

[0030] The present invention uses argon to etch SiO2, and annealing, N-Plasma etching and subsequent growth processes can be performed in the same device. Compared with atomic layer etching (ALE), this in-situ etching process reduces the contact between the substrate and the external environment, avoiding subsequent oxidation by oxygen in the air, and argon etching has a fast speed, low cost, low equipment requirements, simple operation, and easy process control and implementation. However, due to the poor selectivity of argon etching, it is easy to produce etching sputtering effects between materials, resulting in uneven etching surface. The present invention repairs lattice damage through annealing, reduces surface defects caused by argon etching, improves surface flatness, and allows nitrogen plasma to nitride the substrate surface more evenly. As shown in Figure 3 (b).

[0031] S3: performing surface nitridation treatment on the silicon substrate to form a Si3N4 layer on the surface of the silicon substrate.

[0032] Surface nitriding treatment includes the following steps: S31: placing the silicon substrate in a vacuum chamber of the MBE, setting the temperature to 420-550° C., and introducing nitrogen gas at a flow rate of 0.9-1.8 sccm into the vacuum chamber; wherein the duration of the nitrogen gas is 4-7 min.

[0033] S32: treating the silicon substrate with nitrogen-containing plasma at a power of 220-370 W for 10-24 min.

[0034] S33: Raise the temperature to 500-650°C, perform annealing for 25-35 minutes, and then turn off the nitrogen gas source and the nitrogen-containing plasma RF source.

[0035] S34: After the temperature in the vacuum chamber drops to room temperature, take out the silicon substrate after nitridation treatment; wherein, the silicon substrate after nitridation treatment has a Si3N4 layer on at least one side of the surface.

[0036] The present invention uses nitrogen plasma to treat the surface of a silicon substrate so that a Si3N4 layer is formed on the surface of at least one side of the silicon substrate, so that the termination surface presents Si-N bonds with lattice periodicity. Compared with a single silicon substrate, the surface of the Si3N4 layer has potential fluctuations, which can induce the redistribution of charges on the surface of the two-dimensional material graphene, thereby realizing remote epitaxial nitride film on the silicon substrate.

[0037] S4: growing a single graphene layer on copper foil.

[0038] The material of the single-layer graphene layer can be single-crystal graphene or polycrystalline graphene; growing a single-layer graphene includes the following steps: S41: placing the copper foil in a quartz tube furnace at a temperature of 1000-1200° C., introducing hydrogen gas at a flow rate of 10-15 sccm into the quartz tube furnace, and annealing for 10-25 minutes.

[0039] S42: Under a pressure of 1-3 torr, methane with a flow rate of 5-10 sccm and hydrogen with a flow rate of 50-100 sccm are introduced into the quartz tube furnace for 20-30 minutes to grow a single-layer graphene layer on the copper foil.

[0040] S5: transferring the single-layer graphene layer onto the surface of the silicon substrate having the Si3N4 layer.

[0041] A single-layer graphene layer is adhered using polymethyl methacrylate (PMMA) and peeled off from the copper foil, and then covered onto a Si3N4 layer / silicon substrate by wet transfer to form a single-layer graphene / Si3N4 / Si structure.

[0042] The present invention alleviates the lattice mismatch of the substrate by transferring two-dimensional materials (single-layer graphene); the (100) silicon substrate without surface nitridation has no potential fluctuation on its surface and has no effect on graphene, while the Si3N4 layer is formed on the surface of the silicon substrate after nitridation. The surface charge distribution of the Si3N4 layer is uneven and has potential fluctuation, which can induce charge redistribution on the graphene surface and is beneficial to the subsequent epitaxial growth of nitride.

[0043] S6: Remote epitaxial growth of a nitride film on the graphene layer.

[0044] The nitride film can be a single crystal nitride film. The lattice information of the nitride film is the same as the lattice structure information of the Si3N4 layer, preferably a hexagonal system, more preferably a hexagonal wurtzite structure. The remote epitaxy in the present invention means that the lattice information of the Si3N4 layer can affect the surface potential of the graphene, and further epitaxy an epitaxial layer with the same lattice information as the Si3N4 layer is formed on the graphene layer.

[0045] The nitride film of the present invention may specifically be gallium nitride or aluminum nitride.

[0046] In some embodiments, when the material of the nitride film is gallium nitride, remote epitaxial nitride growth includes the following steps: S61a: At a temperature of 600-800°C, a nitrogen source with a flow rate of 8000-14000 sccm, a gallium source with a flow rate of 30-80 sccm and a carrier gas are introduced for 5-30 minutes to grow a nucleation layer.

[0047] The gallium source is trimethylgallium (TMGa), the nitrogen source is NH3, and the carrier gas is a mixed gas consisting of nitrogen with a flow rate of 400 sccm-600 sccm and hydrogen with a flow rate of 40 sccm-60 sccm.

[0048] S62a: Under the condition of temperature of 1000-1200°C, a nitrogen source with a flow rate of 5000-8000 sccm, a gallium source with a flow rate of 30-90 sccm and a carrier gas are introduced, and the reaction is carried out for 150-200 min to grow a thin film layer on the nucleation layer to obtain a nitride thin film (i.e., gallium nitride thin film).

[0049] In some other embodiments, when the material of the nitride film is aluminum nitride, the remote epitaxial nitride comprises the following steps: S61b: Under the condition of temperature of 800-1100°C, a nitrogen source with a flow rate of 8000-14000 sccm, an aluminum source with a flow rate of 30-80 sccm and a carrier gas are introduced, and the reaction is carried out for 5-30 minutes to grow a nucleation layer.

[0050] The aluminum source is trimethylaluminium (TMAl), the nitrogen source is NH3, and the carrier gas is a mixed gas consisting of nitrogen with a flow rate of 400 sccm-600 sccm and hydrogen with a flow rate of 40 sccm-60 sccm.

[0051] S62b: Under the condition of temperature of 1200-1400°C, a nitrogen source with a flow rate of 5000-8000 sccm, an aluminum source with a flow rate of 30-90 sccm and a carrier gas are introduced, and the reaction is carried out for 150-200 min to grow a thin film layer on the nucleation layer to obtain a nitride film (i.e., aluminum nitride film).

[0052] The nitride thin film prepared by the above method can be applied to semiconductor devices.

[0053] Example 1 See also Figure 1 and Figure 2 The method for remote epitaxially growing a nitride film on a silicon substrate of this embodiment comprises the following specific steps: S1: Prepare silicon substrate.

[0054] The silicon substrate in this embodiment is a single crystal silicon substrate with a (100) plane.

[0055] S2: performing surface treatment on the silicon substrate.

[0056] S21: cleaning the surface of the silicon substrate.

[0057] The silicon substrate was subjected to organic cleaning, including ultrasonic cleaning in an acetone solution for 5 min, ultrasonic cleaning in an isopropanol solution for 5 min, and finally ultrasonic cleaning in water for 5 min.

[0058] S22: placing the cleaned silicon substrate in an MBE vacuum chamber, introducing argon gas into the MBE vacuum chamber, and etching the oxide layer on the surface of the cleaned silicon substrate using the argon gas.

[0059] The material of the oxide layer is SiO2, and the cleaned silicon substrate can be etched by using an argon etching method. The process conditions of the argon etching in this embodiment include a pressure of 5×10 6 torr, temperature is 400°C, filament current is 8 mA, high voltage energy is 500 eV and treatment time is 15 min.

[0060] S23: After the argon etching is completed, the temperature in the MBE vacuum chamber is increased to 600° C., and the silicon substrate is annealed for 30 minutes to repair the surface lattice of the silicon substrate.

[0061] In this embodiment, argon etching is performed in the MBE vacuum chamber to etch away the surface oxide layer, and then annealing is performed to flatten the surface and repair the lattice, so that the surface flatness of the silicon substrate is further improved. For example, FIG3 (a) is an AFM photo of a silicon substrate before surface argon etching, and FIG3 (b) is an AFM photo of a silicon substrate after surface argon etching and annealing; the surface roughness RMS (Root Mean Square) of the silicon substrate in FIG3 (a) is 1.082nm, and the surface roughness RMS of the silicon substrate in FIG3 (b) is 0.487nm. After argon etching and annealing, the surface roughness RMS of the silicon substrate becomes smaller.

[0062] S3: performing surface nitridation treatment on the silicon substrate to form a Si3N4 layer on the surface of the silicon substrate.

[0063] Surface nitriding treatment includes the following steps: S31: placing the silicon substrate in a vacuum chamber of the MBE, setting the temperature to 500° C., and introducing nitrogen gas at a flow rate of 1.5 sccm into the vacuum chamber; wherein the duration of the nitrogen gas is 5 min.

[0064] S32: The silicon substrate is treated with nitrogen-containing plasma at a power of 300 W for 20 min.

[0065] S33: After the nitrogen-containing plasma treatment is completed, the temperature is raised to 600°C and annealed for 30 min, and then the N2 gas source and the nitrogen-containing plasma RF source are turned off to stabilize the Si3N4 layer on the surface of the silicon substrate, repair the interface and reduce stress.

[0066] S34: After the temperature in the vacuum chamber drops to room temperature, take out the silicon substrate after nitridation treatment; wherein, the silicon substrate after nitridation treatment has a Si3N4 layer on at least one side of the surface.

[0067] S4: growing a single graphene layer on copper foil.

[0068] The material of the single-layer graphene layer can be single-crystal graphene or polycrystalline graphene; growing a single-layer graphene includes the following steps: S41: placing the copper foil in a quartz tube furnace at a temperature of 1100° C., introducing hydrogen gas at a flow rate of 12 sccm into the quartz tube furnace, and annealing for 15 min; S42: Under a pressure of 2 torr, methane with a flow rate of 8 sccm and hydrogen with a flow rate of 80 sccm were introduced into the quartz tube furnace for 25 min to grow a single-layer graphene layer on the copper foil.

[0069] S5: Covering a single-layer graphene layer onto the surface of the silicon substrate having the Si3N4 layer.

[0070] After the growth of the single-layer graphene layer is completed, polymethyl methacrylate is used to adhere the graphene to peel the single-layer graphene layer from the copper foil, and then the single-layer graphene layer is covered on the side surface of the silicon substrate having the Si3N4 layer by wet transfer to form a single-layer graphene / Si3N4 / Si structure.

[0071] The charge density contour diagram of the substrate without surface nitridation treatment and the substrate with surface nitridation treatment is shown in the figure. Figure 4 As shown, SLG stands for single-layer graphene. Figure 4 (a) Figure 4 (b) are the atomic structure diagram of SLG / Si and the charge density contour diagram of the substrate; Figure 4 (c) Figure 4 (d) are the atomic structure diagram of SLG / Si3N4 / Si and the charge density contour map of the substrate. In the charge density contour map, the charge density of graphene is subtracted from the total charge density of the system to eliminate the influence of the background charge density of graphene, thereby reflecting the planar charge density distribution of the substrate. Red indicates negative charge areas, and blue indicates positive charge areas. Figure 4 It can be seen that in the SLG / Si system, the graphene surface shows almost no charge density redistribution from the silicon substrate. In the SLG / Si3N4 / Si system, the positive and negative charge regions are on some top sites (T) and bridge sites (B) of SLG, which are the manifestation of the substrate's charge induction on graphene, which can promote the adsorption and nucleation of gallium and nitrogen atoms, and then realize remote epitaxial growth.

[0072] S6: remotely epitaxially growing a nitride film on the graphene layer, wherein the lattice information of the nitride film is the same as the lattice structure information of the Si3N4 layer.

[0073] The material of the nitride film in this embodiment is gallium nitride, and the remote epitaxial nitride includes the following steps: S61a: At a temperature of 700°C, a nitrogen source with a flow rate of 10,000 sccm, a gallium source with a flow rate of 60 sccm, and a carrier gas were introduced for 20 minutes to grow a nucleation layer.

[0074] The gallium source is trimethylgallium, the nitrogen source is NH3, and the carrier gas is a mixed gas consisting of nitrogen with a flow rate of 500 sccm and hydrogen with a flow rate of 50 sccm.

[0075] S62a: At a temperature of 1100° C., a nitrogen source with a flow rate of 6000 sccm, a gallium source with a flow rate of 60 sccm, and a carrier gas are introduced for 180 min to grow a thin film layer on the nucleation layer to obtain a gallium nitride thin film.

[0076] Example 2 The difference between this embodiment and embodiment 1 lies in the difference in step S6. The nitride film in this embodiment is aluminum nitride, and the remote epitaxial nitride includes the following steps: S61b: At a temperature of 1000°C, a nitrogen source with a flow rate of 12000 sccm, an aluminum source with a flow rate of 60 sccm, and a carrier gas were introduced for 20 minutes to grow a nucleation layer; The aluminum source is trimethylaluminum, the nitrogen source is NH3, and the carrier gas is a mixed gas consisting of nitrogen with a flow rate of 500 sccm and hydrogen with a flow rate of 50 sccm.

[0077] S62b: At a temperature of 1300° C., a nitrogen source with a flow rate of 6000 sccm, an aluminum source with a flow rate of 60 sccm, and a carrier gas are introduced and reacted for 180 minutes to grow a thin film layer on the nucleation layer to obtain an aluminum nitride thin film.

[0078] Example 3 The method for remote epitaxial growth of a nitride film on a silicon substrate provided in this embodiment comprises the following specific steps: S1: Prepare silicon substrate.

[0079] The silicon substrate in this embodiment is a single crystal silicon substrate with a (100) plane.

[0080] S2: performing surface treatment on the silicon substrate.

[0081] S21: cleaning the surface of the silicon substrate.

[0082] First, ultrasonic cleaning was performed in acetone solution for 8 min, then ultrasonic cleaning was performed in isopropanol solution for 8 min, and finally ultrasonic cleaning was performed in water for 8 min.

[0083] S22: placing the cleaned silicon substrate in an MBE vacuum chamber, introducing argon gas into the MBE vacuum chamber, and etching the oxide layer on the surface of the cleaned silicon substrate using the argon gas.

[0084] The material of the oxide layer is SiO2. The cleaned silicon substrate can be etched by using an argon etching method. The process conditions of the argon etching in this embodiment include a pressure of 4.5×10 6 torr, temperature was 380°C, filament current was 7 mA, high voltage energy was 480 eV, and treatment time was 20 min.

[0085] S23: After the argon etching is completed, the temperature in the MBE vacuum chamber is increased to 500° C., and the silicon substrate is annealed for 35 minutes to repair the surface lattice of the silicon substrate.

[0086] In this embodiment, argon etching is performed in an MBE vacuum chamber to etch away the surface oxide layer, and then annealing is performed to flatten the surface and repair the crystal lattice, so that the surface flatness of the silicon substrate is further improved.

[0087] S3: performing surface nitridation treatment on the silicon substrate to form a Si3N4 layer on the surface of the silicon substrate.

[0088] Surface nitriding treatment includes the following steps: S31: placing the silicon substrate in a vacuum chamber of the MBE, setting the temperature to 420° C., and introducing nitrogen gas at a flow rate of 0.9 sccm into the vacuum chamber; wherein the duration of the nitrogen gas is 7 min.

[0089] S32: The silicon substrate is treated with nitrogen-containing plasma at a power of 220 W for 24 min.

[0090] S33: After the nitrogen-containing plasma treatment is completed, the temperature is raised to 500°C and annealed for 35 min, and then the N2 gas source and the nitrogen-containing plasma RF source are turned off.

[0091] S34: After the temperature in the vacuum chamber drops to room temperature, take out the silicon substrate after nitridation treatment; wherein, the silicon substrate after nitridation treatment has a Si3N4 layer on at least one side of the surface.

[0092] S4: growing a single graphene layer on copper foil.

[0093] The material of the single-layer graphene layer can be single-crystal graphene or polycrystalline graphene; growing a single-layer graphene includes the following steps: S41: placing the copper foil in a quartz tube furnace at a temperature of 1000°C, introducing hydrogen gas at a flow rate of 10 sccm into the quartz tube furnace, and annealing for 25 min; S42: Under a pressure of 1 torr, methane with a flow rate of 5 sccm and hydrogen with a flow rate of 50 sccm were introduced into the quartz tube furnace for 30 min to grow a single-layer graphene layer on the copper foil.

[0094] S5: Covering a single-layer graphene layer onto the surface of the silicon substrate having the Si3N4 layer.

[0095] After the growth of the single-layer graphene layer is completed, polymethyl methacrylate is used to adhere the graphene to peel the single-layer graphene layer from the copper foil, and then the single-layer graphene layer is covered on the side surface of the silicon substrate having the Si3N4 layer by wet transfer to form a single-layer graphene / Si3N4 / Si structure.

[0096] S6: remotely epitaxially growing a nitride film on the graphene layer, wherein the lattice information of the nitride film is the same as the lattice structure information of the Si3N4 layer.

[0097] The material of the nitride film in this embodiment is gallium nitride, and the remote epitaxial nitride includes the following steps: S61a: At a temperature of 600°C, a nitrogen source with a flow rate of 8000 sccm, a gallium source with a flow rate of 30 sccm, and a carrier gas were introduced for 30 minutes to grow a nucleation layer.

[0098] The gallium source is trimethylgallium, the nitrogen source is NH3, and the carrier gas is a mixed gas consisting of nitrogen with a flow rate of 400 sccm and hydrogen with a flow rate of 40 sccm.

[0099] S62a: At a temperature of 1000° C., a nitrogen source with a flow rate of 5000 sccm, a gallium source with a flow rate of 30 sccm, and a carrier gas are introduced for 200 min to grow a gallium nitride film on the nucleation layer.

[0100] Example 4 The difference between this embodiment and embodiment 3 lies in the difference in step S6. In this embodiment, the nitride film is aluminum nitride, and the remote epitaxial nitride includes the following steps: S61b: At a temperature of 800°C, a nitrogen source with a flow rate of 8000 sccm, an aluminum source with a flow rate of 30 sccm, and a carrier gas were introduced for 30 minutes to grow a nucleation layer; The aluminum source is trimethylaluminum, the nitrogen source is NH3, and the carrier gas is a mixed gas consisting of nitrogen with a flow rate of 400 sccm and hydrogen with a flow rate of 40 sccm.

[0101] S62b: At a temperature of 1200°C, a nitrogen source with a flow rate of 5000 sccm, an aluminum source with a flow rate of 30 sccm, and a carrier gas are introduced and reacted for 200 minutes to grow a thin film layer on the nucleation layer to obtain an aluminum nitride film.

[0102] Example 5

[0103] The method for remote epitaxial growth of a nitride film on a silicon substrate provided in this embodiment comprises the following specific steps: S1: Prepare silicon substrate.

[0104] The silicon substrate in this embodiment is a single crystal silicon substrate with a (100) plane.

[0105] S2: performing surface treatment on the silicon substrate.

[0106] S21: cleaning the surface of the silicon substrate.

[0107] First, ultrasonic cleaning was performed in acetone solution for 10 min, then ultrasonic cleaning was performed in isopropanol solution for 10 min, and finally ultrasonic cleaning was performed in water for 10 min.

[0108] S22: placing the cleaned silicon substrate in an MBE vacuum chamber, introducing argon gas into the MBE vacuum chamber, and etching the oxide layer on the surface of the cleaned silicon substrate using the argon gas.

[0109] The material of the oxide layer is SiO2. The cleaned silicon substrate can be etched by using an argon etching method. The process conditions of the argon etching in this embodiment include a pressure of 5.5×10 6 torr, the temperature was 420°C, the filament current was 9 mA, the high voltage energy was 520 eV, and the processing time was 10 min.

[0110] S23: After the argon etching is completed, the temperature in the MBE vacuum chamber is increased to 650° C., and the silicon substrate is annealed for 25 minutes to repair the surface lattice of the silicon substrate.

[0111] In this embodiment, argon etching is performed in an MBE vacuum chamber to etch away the surface oxide layer, and then annealing is performed to flatten the surface and repair the crystal lattice, so that the surface flatness of the silicon substrate is further improved.

[0112] S3: performing surface nitridation treatment on the silicon substrate to form a Si3N4 layer on the surface of the silicon substrate.

[0113] Surface nitriding treatment includes the following steps: S31: placing the silicon substrate in a vacuum chamber of the MBE, setting the temperature to 550° C., and introducing nitrogen gas at a flow rate of 1.8 sccm into the vacuum chamber; wherein, the duration of the nitrogen gas is 4 min.

[0114] S32: The silicon substrate is treated with nitrogen-containing plasma at a power of 370 W for 10 min.

[0115] S33: After the nitrogen-containing plasma treatment is completed, the temperature is raised to 650° C. and annealed for 25 min, and then the N2 gas source and the nitrogen-containing plasma RF source are turned off.

[0116] S34: After the temperature in the vacuum chamber drops to room temperature, take out the silicon substrate after nitridation treatment; wherein, the silicon substrate after nitridation treatment has a Si3N4 layer on at least one side of the surface.

[0117] S4: growing a single graphene layer on copper foil.

[0118] The material of the single-layer graphene layer can be single-crystal graphene or polycrystalline graphene; growing a single-layer graphene includes the following steps: S41: placing the copper foil in a quartz tube furnace at a temperature of 1200°C, introducing hydrogen gas at a flow rate of 15 sccm into the quartz tube furnace, and annealing for 10 min; S42: Under a pressure of 3 torr, methane with a flow rate of 10 sccm and hydrogen with a flow rate of 100 sccm were introduced into the quartz tube furnace for 20 min to grow a single-layer graphene layer on the copper foil.

[0119] S5: Covering a single-layer graphene layer onto the surface of the silicon substrate having the Si3N4 layer.

[0120] After the growth of the single-layer graphene layer is completed, polymethyl methacrylate is used to adhere the graphene to peel the single-layer graphene layer from the copper foil, and then the single-layer graphene layer is covered on the surface of the Si3N4 layer / silicon substrate by wet transfer to form a single-layer graphene / Si3N4 / Si structure.

[0121] S6: remotely epitaxially growing a nitride film on the graphene layer, wherein the lattice information of the nitride film is the same as the lattice structure information of the silicon substrate.

[0122] The material of the nitride film in this embodiment is gallium nitride, and the remote epitaxial nitride includes the following steps: S61a: At a temperature of 800°C, a nitrogen source with a flow rate of 14,000 sccm, a gallium source with a flow rate of 80 sccm, and a carrier gas were introduced for 5 minutes to grow a nucleation layer.

[0123] The gallium source is trimethylgallium, the nitrogen source is NH3, and the carrier gas is a mixed gas consisting of a nitrogen gas with a flow rate of 600 sccm and a hydrogen gas with a flow rate of 60 sccm.

[0124] S62a: At a temperature of 1200° C., a nitrogen source with a flow rate of 8000 sccm, a gallium source with a flow rate of 90 sccm, and a carrier gas are introduced for 150 minutes to grow a thin film layer on the nucleation layer to obtain a gallium nitride thin film.

[0125] Example 6 The difference between this embodiment and embodiment 5 lies in the difference in step S6. The nitride film in this embodiment is aluminum nitride, and the remote epitaxial nitride includes the following steps: S61b: At a temperature of 1100°C, a nitrogen source with a flow rate of 14000 sccm, an aluminum source with a flow rate of 80 sccm, and a carrier gas were introduced for 5 minutes to grow a nucleation layer; The aluminum source is trimethylaluminum, the nitrogen source is NH3, and the carrier gas is a mixed gas consisting of nitrogen with a flow rate of 600 sccm and hydrogen with a flow rate of 60 sccm.

[0126] S62b: At a temperature of 1400°C, a nitrogen source with a flow rate of 8000 sccm, an aluminum source with a flow rate of 90 sccm, and a carrier gas are introduced and reacted for 150 minutes to grow a thin film layer on the nucleation layer to obtain an aluminum nitride film.

[0127] The present invention utilizes the means of surface nitridation modification and the remote epitaxial growth method to enable the silicon substrate that cannot be remotely epitaxially grown to have the remote epitaxial capability, that is, to be able to remotely epitaxially grow a nitride film on the silicon substrate, while improving the quality of the epitaxial film and also achieving CMOS compatibility. Compared with the existing technology, the advantages of the present invention are: 1) The single-layer graphene layer and the nitride film of the present invention are not bonded by covalent bonds, but by weak electrostatic forces between van der Waals forces and covalent bonds, so as to achieve the growth of a nearly stress-free nitride film on a silicon substrate and improve the growth quality of the nitride film.

[0128] 2) There is a large thermal mismatch between the commonly used silicon substrate and the nitride film, and the quality of the epitaxial nitride film is poor, which seriously affects the performance and reliability of the device. The present invention can alleviate the thermal stress in the epitaxial process and improve the quality of the nitride film by using graphene, a good thermal conductive material.

[0129] 3) It is difficult to directly peel off the epitaxial nitride film on the silicon substrate, and the peeling operation is complicated, resulting in a large number of defects and damage. The present invention grows a nitride film on a single-layer graphene layer, which can make the lattice structure information of the nitride film the same as the lattice structure information of the Si3N4 layer on the surface of the silicon substrate, alleviate the large lattice mismatch and thermal mismatch existing when the nitride film is epitaxially grown on the silicon substrate, and reduce the defects and stress caused by the lattice mismatch and thermal mismatch. At the same time, the weak electrostatic force between the single-layer graphene layers helps to peel off the nitride film, reducing the probability of defects and damage in the nitride film.

[0130] 4) The present invention utilizes nitrogen plasma to directly modify the surface of the silicon substrate, which is simple to operate, has fewer steps, and is suitable for large-scale industrial promotion.

[0131] The above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with this technology to understand the contents of the present invention and implement them accordingly. They cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

[0132] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

Claims

1. A method for remote epitaxial growth of a nitride film on a silicon substrate, characterized in that: The steps include: Performing a surface nitridation treatment on the silicon substrate to form a Si3N4 layer on the surface of the silicon substrate; Forming a single-layer graphene layer on a surface of the silicon substrate having the Si3N4 layer; remote epitaxially growing a nitride film on the single-layer graphene layer; The lattice information of the nitride film is the same as the lattice structure information of the Si3N4 layer.

2. The method according to claim 1, characterized in that The surface nitriding treatment comprises the following steps: Placing the silicon substrate in an MBE vacuum chamber, setting the temperature to 420-550° C., and introducing nitrogen gas with a flow rate of 0.9-1.8 sccm into the MBE vacuum chamber; wherein the duration of the nitrogen gas is 4-7 min; Treating the silicon substrate with nitrogen-containing plasma at a power of 220-370 W for 10-24 min; After the temperature in the MBE vacuum chamber drops to room temperature, the silicon substrate after nitridation is taken out; wherein, the silicon substrate after nitridation has a Si3N4 layer on at least one side of its surface.

3. The method according to claim 1, characterized in that The material of the nitride film is gallium nitride, and the remote epitaxial growth of the nitride film comprises the following steps: Under the condition of temperature of 600-800°C, a nitrogen source with a flow rate of 8000-14000 sccm, a gallium source with a flow rate of 30-80 sccm and a carrier gas are introduced, and the reaction is carried out for 5-30 minutes to grow a nucleation layer; Under the condition of a temperature of 1000-1200° C., a nitrogen source with a flow rate of 5000-8000 sccm, a gallium source with a flow rate of 30-90 sccm, and a carrier gas are introduced, and the reaction is carried out for 150-200 min to grow a thin film layer on the nucleation layer to obtain the nitride thin film; Wherein, the carrier gas includes nitrogen with a flow rate of 400 sccm-600 sccm and hydrogen with a flow rate of 40 sccm-60 sccm.

4. The method according to claim 1, characterized in that: The material of the nitride film is aluminum nitride, and the remote epitaxial growth of the nitride film comprises the following steps: Under the condition of temperature of 800-1100° C., a nitrogen source with a flow rate of 8000-14000 sccm, an aluminum source with a flow rate of 30-80 sccm and a carrier gas are introduced, and the reaction is carried out for 5-30 minutes to grow a nucleation layer; Under the condition of temperature of 1200-1400° C., introducing a nitrogen source with a flow rate of 5000-8000 sccm, an aluminum source with a flow rate of 30-90 sccm and a carrier gas, reacting for 150-200 min to grow a thin film layer on the nucleation layer to obtain the nitride thin film; Wherein, the carrier gas includes nitrogen with a flow rate of 400 sccm-600 sccm and hydrogen with a flow rate of 40 sccm-60 sccm.

5. The method according to claim 1, characterized in that The silicon substrate is a single crystal silicon substrate with a (100) plane; And / or, before the surface nitridation treatment of the silicon substrate is performed, the following steps are included: Cleaning the surface of the silicon substrate; The cleaned silicon substrate is placed in an MBE vacuum chamber, argon gas is introduced into the MBE vacuum chamber, and the oxide layer on the surface of the cleaned silicon substrate is etched using the argon gas.

6. The method according to claim 5, characterized in that The process conditions of the argon etching include a pressure of 4.5-5.5×10 6 torr, temperature of 380-420°C, filament current of 7-9 mA, high voltage energy of 480-520 eV and treatment time of 10-20 min.

7. The method according to claim 1, characterized in that The single-layer graphene layer is grown and covered on the silicon substrate by the following steps: Growing a single graphene layer on copper foil; The single-layer graphene layer is peeled off from the copper foil and covered onto the surface of the silicon substrate having the Si3N4 layer by wet transfer.

8. The method according to claim 7, characterized in that The single-layer graphene layer is grown by the following steps: The copper foil is placed in a quartz tube furnace at a temperature of 1000-1200° C., hydrogen gas with a flow rate of 10-15 sccm is introduced into the quartz tube furnace, and annealing is performed for 10-25 minutes; Under the condition of a pressure of 1-3 torr, methane with a flow rate of 5-10 sccm and hydrogen with a flow rate of 50-100 sccm are introduced into the quartz tube furnace for 20-30 minutes to grow the single-layer graphene layer on the copper foil.

9. A nitride thin film, characterized in that: The nitride film is prepared by the method according to any one of claims 1 to 8.

10. A semiconductor device, characterized in that: Comprising the nitride thin film as claimed in claim 9.

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