Silicon-based material and preparation method thereof

Abstract

The invention relates to the technical field of silicon-based materials, in particular to a preparation method of a silicon-based material and the silicon-based material. The preparation method comprises the following steps: S1, sequentially carrying out acid pickling and high-temperature annealing on a substrate material to prepare a precursor; s2, purging the deposition furnace; s3, simultaneously introducing first gas and hydrogen into the deposition furnace to be in contact with the precursor to prepare a silicon-based material intermediate; the flow V1 of the first gas introduced into the deposition furnace is continuously and progressively increased along with time, the flow V2 of the hydrogen introduced into the deposition furnace is continuously and progressively decreased along with time, and V1 + V2 is equal to 200; s4, second gas and hydrogen are introduced into the deposition furnace to make contact with the silicon-based material intermediate, and a second coating is formed on the surface of the silicon-based material intermediate; wherein the ratio of the flow of the second gas introduced into the deposition furnace to the flow of the hydrogen is (5-60): 1. According to the silicon-based material disclosed by the invention, the bonding strength between the silicon carbide coating and the matrix is relatively high, and the consistency and the stability of the overall structure of the silicon-based material are relatively high.

Description

Technical Field

[0001] This invention relates to the field of silicon-based materials technology, and more specifically to a method for preparing silicon-based materials and the silicon-based materials prepared by the method. Background Technology

[0002] While silicon (Si) has become a core material in the semiconductor field due to its mature processing technology, low cost, and high integration, its inherent limitations restrict its application in certain scenarios: poor high-temperature resistance, with silicon devices exhibiting significant performance degradation above 200°C; weak high-voltage resistance, as silicon has a low breakdown electric field (approximately 0.3 MV / cm); and insufficient wear and corrosion resistance, as silicon is easily damaged by mechanical friction or corrosive environments. Therefore, to improve the lifespan of silicon devices, a SiC coating is deposited on the silicon surface, which can impart higher temperature resistance, pressure resistance, wear resistance, and corrosion resistance to the devices while retaining the advantages of the silicon substrate. However, the large difference in thermal expansion coefficients between the SiC coating and the silicon substrate leads to significant thermal stress during deposition, making it prone to thermal mismatch. This results in coating cracking and peeling during fabrication, low coating adhesion strength, and a short lifespan. Summary of the Invention

[0003] CVD silicon carbide coating is a thin film of silicon carbide prepared by chemical vapor deposition. It has many advantages, such as excellent chemical corrosion resistance and high temperature resistance, and has a wide range of applications. The mainstream process for silicon carbide (SiC) coating is currently deposition on a high-purity hydrostatic graphite substrate. Although isostatic graphite has excellent performance parameters and its coefficient of thermal expansion is close to that of silicon carbide, as the substrate for SiC coating deposition, it has a relatively high particle count and poor surface roughness, which greatly affects the quality of the deposited silicon carbide coating. Furthermore, isostatic graphite is very expensive and is currently mainly imported from abroad.

[0004] Silicon wafers, as a mature semiconductor substrate, possess advantages such as high purity, no contamination, excellent surface roughness, and low cost. However, the lattice constants of silicon and silicon carbide differ by approximately 20% (Si: 5.43 Å, SiC: 4.36 Å). Furthermore, the coefficients of thermal expansion of silicon and silicon carbide differ significantly: silicon (2.6 × 10⁻⁶) has a higher coefficient of thermal expansion than silicon (2.6 × 10⁻⁶). -6 / K) and SiC (4.2×10 -6 The expansion rates of silicon carbide coatings vary at high temperatures, and a large amount of thermal stress is generated during cooling. Direct deposition of silicon carbide coatings on the surface of silicon substrates is prone to cracking or peeling due to stress concentration.

[0005] In existing technologies, the common method for fabricating SiC coatings on silicon substrates is to add a buffer layer. This involves introducing a carbon source gas before the silicon source gas, with the silicon substrate providing Si atoms to create a thin SiC buffer layer on the silicon substrate surface, followed by SiC coating deposition. However, the thickness of both the SiC buffer layer and the deposited SiC coating obtained using this method is limited, and the thinness of the deposited SiC coating cannot meet practical requirements. Furthermore, the inconsistency in the thermal expansion coefficients of the silicon substrate and the SiC coating leads to warping and irregular deformation of the device due to the expansion stress of the coating during cooling, thus affecting device assembly.

[0006] To address the aforementioned technical problems in the preparation of silicon carbide coatings on silicon substrates in existing technologies, this invention provides a method for preparing silicon-based materials and the silicon-based material obtained by this method. The silicon-based material prepared by the method of this invention achieves a continuous transition in the difference in thermal expansion coefficients between the silicon substrate and the silicon carbide coating, alleviates thermal stress, improves the bonding strength between the silicon carbide coating and the substrate, and enhances the overall structural consistency and stability of the silicon-based material.

[0007] To achieve the above objectives, the first aspect of the present invention provides a method for preparing a silicon-based material, wherein the preparation method includes the following steps: S1: Pretreatment: the substrate material is first contacted with an acid solution, and then annealed at high temperature in a deposition furnace under a protective atmosphere to obtain a precursor with an activated surface; S2: Exhaust: Heat the deposition furnace to the first temperature T1, and purge the deposition furnace with inert gas at the same time; S3: First vapor deposition reaction: A first gas and hydrogen are simultaneously introduced into a deposition furnace to contact the precursor with the activated surface, and a first vapor deposition reaction is performed to form a first coating on the surface of the precursor with the activated surface, thereby obtaining a silicon-based material intermediate; wherein, the first gas includes silicon source gas and carbon source gas, the flow rate of the first gas into the deposition furnace is V1, in sccm, and V1 continuously increases with time, the flow rate of hydrogen into the deposition furnace is V2, in sccm, and V2 continuously decreases with time, and V1 and V2 satisfy the following relationship: V1 + V2 = 200; S4: Second vapor deposition reaction: A second gas and hydrogen are introduced into a deposition furnace and brought into contact with the silicon-based material intermediate to perform a second vapor deposition reaction, forming a second coating on the surface of the silicon-based material intermediate; wherein, the second gas includes silicon source gas and carbon source gas, and the ratio of the flow rate of the second gas into the deposition furnace to the flow rate of hydrogen into the deposition furnace is (5-60):1.

[0008] The second invention provides a silicon-based material prepared by the preparation method described in the first aspect of the invention.

[0009] By employing the above technical solution, the present invention has at least the following advantages compared with the prior art: In the method for preparing silicon-based materials of the present invention, during the first vapor deposition reaction, the sum of the flow rate V1 of the first gas entering the deposition furnace and the flow rate V2 of the hydrogen entering the deposition furnace satisfies 200, and the flow rate V1 of the first gas entering the deposition furnace continuously increases with time, while the flow rate V2 of the hydrogen entering the deposition furnace continuously decreases with time. This enables a gradient change in the Si composition in the first coating generated by the first vapor deposition reaction, forming a gradient structure of continuous change from "silicon layer → silicon-rich layer → silicon carbide layer". This allows for a continuous transition of the difference in thermal expansion coefficient between the substrate material and the first coating, improving thermal stress and increasing the bonding strength between the coating and the substrate material. As a result, the prepared silicon-based material possesses both high structural consistency and high structural stability.

[0010] Other features and advantages of the present invention will be described in detail in the following detailed description section.

[0011] The endpoints and any values ​​of the ranges disclosed herein 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 the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein. Attached Figure Description

[0012] Figure 1 The diagram shows the structure of the silicon-based material of the present invention.

[0013] Figure 2 The image shown is an SEM image of the first and second coatings in the silicon-based material of the present invention. Detailed Implementation

[0014] The following provides a detailed description of specific embodiments of the present invention. It should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the invention. Unless otherwise specified herein, data ranges include endpoints.

[0015] It should be noted that the numerical designations such as "first" and "second" in this invention are only used to distinguish different substances or methods of use, and do not represent a difference in order.

[0016] The first aspect of the present invention provides a method for preparing a silicon-based material, wherein the preparation method includes the following steps: S1: Pretreatment: the substrate material is first contacted with an acid solution, and then annealed at high temperature in a deposition furnace under a protective atmosphere to obtain a precursor with an activated surface; S2: Exhaust: Heat the deposition furnace to the first temperature T1, and purge the deposition furnace with inert gas at the same time; S3: First vapor deposition reaction: A first gas and hydrogen are simultaneously introduced into a deposition furnace to contact the precursor with the activated surface, and a first vapor deposition reaction is performed to form a first coating on the surface of the precursor with the activated surface, thereby obtaining a silicon-based material intermediate; wherein, the first gas includes silicon source gas and carbon source gas, the flow rate of the first gas into the deposition furnace is V1, in sccm, and V1 continuously increases with time, the flow rate of hydrogen into the deposition furnace is V2, in sccm, and V2 continuously decreases with time, and V1 and V2 satisfy the following relationship: V1 + V2 = 200; S4: Second vapor deposition reaction: A second gas and hydrogen are introduced into a deposition furnace and brought into contact with the silicon-based material intermediate to perform a second vapor deposition reaction, forming a second coating on the surface of the silicon-based material intermediate; wherein, the second gas includes a silicon source gas and a carbon source gas, and the ratio of the flow rate of the second gas to the flow rate of hydrogen in the deposition furnace is (5-60):1 (e.g., 5:1, 10:1, 15:1, 20:1, 25:1, 30:1, 35:1, 40:1, 45:1, 50:1, 55:1 or 60:1).

[0017] Step S1 is a pretreatment process, which involves acid washing of the substrate material to clean it and remove the oxide layer on its surface. Then, it is annealed at high temperature in a protective atmosphere to obtain a precursor with an activated surface. Silicon is a reactive element that rapidly reacts with oxygen in air to form a silicon dioxide film. If SiC is directly grown on this silicon dioxide film, a fragile and incoherent interface will be formed. This interface will become a weak point in the bonding of the silicon-based material, making it highly susceptible to delamination under stress, leading to the detachment of the substrate material from the coating. Acid washing removes the oxide layer from the substrate material surface, reducing the risk of detachment and removing any potential organic contaminants. This provides a purer silicon atomic surface for subsequent carbon-silicon atomic bonding, ensuring that the substrate material starts from the same pure state for each production run, guaranteeing the repeatability and reliability of the production process, which is crucial for mass production. High-temperature annealing activates the surface, removing residual impurities and moisture from the substrate material after pickling, while also repairing surface defects. Pickled silicon atoms are rough at the atomic scale and have etching defects. High temperature provides sufficient energy to allow silicon atoms to migrate and recombine, causing them to migrate to the lowest energy positions, resulting in a smoother and more regular surface. A smooth surface is more conducive to high-quality epitaxial growth. Moreover, after high-temperature annealing, the dangling bonds of activated silicon atoms on the substrate surface become highly active, eager to form bonds with surrounding elements. When the deposition reaction gas is subsequently introduced, the highly active silicon atoms will quickly react with other carbon-containing molecules, thereby increasing the nucleation density of SiC. High-density uniform nucleation is key to forming a dense and firmly bonded coating, resulting in a coating with high bonding strength.

[0018] After acid washing of the substrate material, some hydrocarbons or other organic impurities will be adsorbed on the surface of the substrate material. After high-temperature annealing, these impurities will desorb and decompose, thereby obtaining an atomically clean substrate material surface. Step S2 is venting. The deposition furnace is vented by purging to remove the gases generated in the pretreatment process from the deposition furnace, creating a clean reaction environment and avoiding interference with the vapor deposition reaction.

[0019] Step S3 is the first vapor deposition reaction, wherein, in the first vapor deposition reaction, a first gas and hydrogen are simultaneously introduced into the deposition furnace to contact the precursor with the activated surface, and the sum of the flow rate V1 of the first gas introduced into the deposition furnace and the flow rate V2 of the hydrogen introduced into the deposition furnace is controlled to satisfy 200, and the flow rate V1 of the first gas introduced into the deposition furnace continuously increases with time, and the flow rate V2 of the hydrogen introduced into the deposition furnace continuously decreases with time.

[0020] In this invention, "continuously decreasing" refers to the flow rate V2 of hydrogen gas entering the deposition furnace decreasing continuously over time at a certain rate; "continuously increasing" refers to the flow rate V1 of the first gas entering the deposition furnace increasing continuously over time at a certain rate. The rate of change for the continuous decreasing flow rate can be 20 sccm / h to 60 sccm / h (e.g., 20 sccm / h, 25 sccm / h, 30 sccm / h, 35 sccm / h, 40 sccm / h, 45 sccm / h, 50 sccm / h, 55 sccm / h, or 60 sccm / h), and the rate of change for the continuous increasing flow rate can be 20 sccm / h to 60 sccm / h (e.g., 20 sccm / h, 25 sccm / h, 30 sccm / h, 35 sccm / h, 40 sccm / h, 45 sccm / h, 50 sccm / h, 55 sccm / h, or 60 sccm / h). It is understood that the rate of increase of the flow rate V1 of the first gas entering the deposition furnace is the same as the rate of decrease of the flow rate V2 of the hydrogen entering the deposition furnace.

[0021] By controlling the conditions of the first gas-phase deposition reaction, the sum of the flow rate V1 of the first gas entering the deposition furnace and the flow rate V2 of the hydrogen entering the deposition furnace is made to satisfy 200. That is, the flow rates V1 and V2 of the first gas entering the deposition furnace have an inverse relationship, and the trends of V1 and V2 are that V1 continuously increases and V2 continuously decreases over time. This allows V1 and V2 to change continuously. Since the flow rate of the first gas is greater than that of the hydrogen in the initial gas flow, the reactions that occur at this time are CH3SiCl3→ CH3+ SiCl3; SiCl3+ H2→ SiCl2+ HCl; SiCl2+ H2→ <si>The first vapor deposition reaction produces a silicon-rich layer near the substrate material. Subsequently, as the flow rate V1 of the hydrogen gas entering the deposition furnace continues to increase and the flow rate V2 of the hydrogen gas entering the furnace continues to decrease, the reaction that occurs is CH3SiCl3 + H2 → SiC + 3HCl. The coating consists of SiC, forming a silicon carbide coating. Therefore, the first vapor deposition reaction enables the formed first coating to have a gradient structure with a continuous change from "silicon layer (substrate material) → silicon-rich layer → silicon carbide layer" to the substrate material. In this gradient structure, the change in the coefficient of thermal expansion is small, and the difference in the coefficient of thermal expansion can achieve a continuous transition, thereby effectively alleviating thermal stress and improving the structural consistency and stability of the silicon-based material.

[0022] Step S4 is the second vapor phase deposition. In the second vapor phase deposition, the flow rates of the second gas and hydrogen can remain essentially constant, and the ratio of the flow rate of the second gas into the deposition furnace to the flow rate of hydrogen into the deposition furnace is controlled to be (5-60):1. The reaction that occurs at this time is CH3SiCl3 + H2 → SiC + 3HCl, which produces a silicon carbide coating. This ensures that the molar ratio of carbon atoms to silicon atoms in the obtained silicon carbide coating is approximately 1:1. Silicon carbide with this molar ratio has high chemical stability and corrosion resistance. With a molar ratio of approximately 1:1, each C atom and each Si atom are connected by strong covalent bonds, forming a very stable saturated tetrahedral structure. There are few or no excess dangling bonds or free atoms, which makes the silicon carbide coating extremely inert, with high mechanical strength and hardness. At the same time, the silicon carbide coating also has high thermal stability and oxidation resistance, and consistent and reliable thermophysical properties; thereby improving the structural stability of silicon-based materials.

[0023] Therefore, the method for preparing silicon-based materials of the present invention, by controlling the sum of the flow rates V1 of the first gas entering the deposition furnace and V2 of the hydrogen gas entering the deposition furnace in the first vapor deposition reaction, as well as the changing trends of V1 and V2, can achieve a continuous transition of the coefficient of thermal expansion between the substrate material and the coating in the prepared silicon-based material compared with the prior art, thereby improving the structural consistency and structural stability of the silicon-based material. To further improve the effect, one or more of the technical features can be further optimized.

[0024] In one example, the first gas is trichloromethylsilane (MTS).

[0025] In one example, the flow rate V1 of the first gas introduced into the deposition furnace is 5 sccm-170 sccm (e.g., 5 sccm, 10 sccm, 25 sccm, 30 sccm, 35 sccm, 40 sccm, 45 sccm, 50 sccm, 55 sccm, 60 sccm, 65 sccm, 70 sccm, 75 sccm, 80 sccm, 85 sccm, 90 sccm, 95 sccm, 100 sccm, 105 sccm, 110 sccm, 115 sccm, 120 sccm, 125 sccm, 130 sccm, 135 sccm, 140 sccm, 145 sccm, 150 sccm, 155 sccm, 160 sccm, 165 sccm, or 170 sccm). It is understood that the flow rate V1 of the first gas introduced into the deposition furnace continuously increases over time within the range of 5 sccm-170 sccm.

[0026] In one example, the flow rate V2 of hydrogen gas introduced into the deposition furnace is 195 sccm-30 sccm (e.g., 195 sccm, 190 sccm, 185 sccm, 180 sccm, 175 sccm, 170 sccm, 165 sccm, 160 sccm, 155 sccm, 150 sccm, 145 sccm, 140 sccm, 135 sccm, 130 sccm, 125 sccm, 120 sccm, 115 sccm, 110 sccm, 105 sccm, 100 sccm, 95 sccm, 90 sccm, 85 sccm, 80 sccm, 75 sccm, 70 sccm, 65 sccm, 60 sccm, 55 sccm, 50 sccm, 45 sccm, 40 sccm, 35 sccm, or 30 sccm). It is understandable that the flow rate V2 of hydrogen gas introduced into the deposition furnace decreases continuously over time in the range of 195 sccm-70 sccm.

[0027] According to one specific implementation, V1 and V2 satisfy the following relationship: V1 + V2 = 200, and the flow rate V1 of the first gas entering the deposition furnace is 5 sccm - 170 sccm, and the flow rate V2 of the hydrogen entering the deposition furnace is 195 sccm - 30 sccm. It is understood that the flow rates V1 of the first gas entering the deposition furnace and V2 of the hydrogen entering the deposition furnace can be controlled by a program of automated equipment to ensure that V1 + V2 = 200.

[0028] In one example, the initial value of the flow rate V1 of the first gas introduced into the deposition furnace is 5 sccm-35 sccm (e.g., 5 sccm, 10 sccm, 15 sccm, 20 sccm, 25 sccm, 30 sccm or 35 sccm), and the initial value of the flow rate V2 of the hydrogen introduced into the deposition furnace is 195 sccm-165 sccm (e.g., 195 sccm, 190 sccm, 185 sccm, 180 sccm, 175 sccm, 170 sccm or 165 sccm).

[0029] In one instance, the first vapor deposition reaction ends when V1 gradually increases over time to 120 sccm-170 sccm (e.g., 120 sccm, 123 sccm, 125 sccm, 128 sccm, 130 sccm, 133 sccm, 135 sccm, 138 sccm, 140 sccm, 143 sccm, 145 sccm, 148 sccm, 150 sccm, 153 sccm, 155 sccm, 158 sccm, 160 sccm, 163 sccm, 165 sccm, 168 sccm, or 170 sccm).

[0030] In one example, the conditions for the first vapor deposition reaction include: a deposition temperature of 1200°C–1450°C (e.g., 1200°C, 1230°C, 1250°C, 1280°C, 1300°C, 1330°C, 1350°C, 1380°C, 1400°C, 1430°C, or 1450°C), and a deposition pressure of 30 mbar–300 mbar (e.g., 30 mbar, 50 mbar, or 80 mbar). The deposition temperatures are 100 mbar, 130 mbar, 150 mbar, 180 mbar, 200 mbar, 230 mbar, 250 mbar, 280 mbar, or 300 mbar, with a deposition duration of 3-10 hours (e.g., 3 hours, 3.5 hours, 4 hours, 4.5 hours, 5 hours, 5.5 hours, 6 hours, 6.5 hours, 7 hours, 7.5 hours, 8 hours, 8.5 hours, 9 hours, 9.5 hours, or 10 hours). The deposition temperature of the first vapor-phase deposition reaction is the same as the first temperature T1.

[0031] In one example, in the first vapor deposition reaction, a first carrier gas, which is argon, is also introduced into the deposition furnace along with the first gas and hydrogen. The flow rate of the first carrier gas is 30 sccm-100 sccm (e.g., 30 sccm, 35 sccm, 40 sccm, 45 sccm, 50 sccm, 55 sccm, 60 sccm, 65 sccm, 70 sccm, 75 sccm, 80 sccm, 85 sccm, 90 sccm, 95 sccm or 100 sccm).

[0032] In one example, the conditions for the second vapor-phase deposition reaction include: a deposition temperature of 1200℃-1450℃ (e.g., 1200℃, 1230℃, 1250℃, 1280℃, 1300℃, 1330℃, 1350℃, 1380℃, 1400℃, 1430℃, or 1450℃), a deposition pressure of 30mbar-300mbar (e.g., 30mbar, 50mbar, 80mbar, 100mbar, 130mbar, 150mbar, 180mbar, 200mbar, 230mbar, 250mbar, 280mbar, or 300mbar), and a deposition duration of 5h-20h (e.g., 5h, 8h, 10h, 13h, 15h, 18h, or 20h). The deposition temperature of the second vapor-phase deposition reaction is the same as the first temperature T1.

[0033] In one example, in the second vapor deposition reaction, the volumetric flow rate of the second gas is 170 sccm-160 sccm (e.g., 170 sccm, 169 sccm, 168 sccm, 167 sccm, 166 sccm, 165 sccm, 164 sccm, 163 sccm, 162 sccm, 161 sccm or 160 sccm), and the volumetric flow rate of hydrogen is 30 sccm-40 sccm (e.g., 30 sccm, 31 sccm, 32 sccm, 33 sccm, 34 sccm, 35 sccm, 36 sccm, 37 sccm, 38 sccm, 39 sccm or 40 sccm).

[0034] In one instance, the flow rate of the second gas introduced into the deposition furnace is the same as the flow rate of the first gas at the end of the first vapor deposition reaction.

[0035] In one instance, the flow rate of the second gas introduced into the deposition furnace is the same as the flow rate of the first gas at the end of the first vapor deposition reaction.

[0036] In one example, in the second vapor deposition reaction, the flow rates of the second gas and the hydrogen are fixed, and the sum of the flow rates of the second gas and the hydrogen is 200 sccm.

[0037] According to one specific embodiment, in the second vapor deposition reaction, the flow rate of the second gas and the flow rate of the hydrogen are fixed values, and the sum of the flow rate of the second gas and the flow rate of the hydrogen is 200 sccm. The flow rate of the second gas entering the deposition furnace is the same as the flow rate of the first gas at the end of the first vapor deposition reaction.

[0038] In one example, during the second vapor deposition reaction, a second carrier gas, which is argon, is also introduced into the deposition furnace along with the second gas and hydrogen. The flow rate of the second carrier gas is 50 sccm-150 sccm (e.g., 50 sccm, 55 sccm, 60 sccm, 65 sccm, 70 sccm, 75 sccm, 80 sccm, 85 sccm, 90 sccm, 95 sccm, 100 sccm, 105 sccm, 110 sccm, 115 sccm, 120 sccm, 125 sccm, 130 sccm, 135 sccm, 140 sccm, 145 sccm, or 150 sccm).

[0039] According to a specific embodiment, the conditions for the first vapor-phase deposition reaction include: a deposition temperature of 1200℃-1450℃, a deposition pressure of 30mbar-300mbar, and a deposition duration of 3h-10h. In the first vapor-phase deposition reaction, a first carrier gas, which is argon, is also introduced into the deposition furnace along with the first gas and hydrogen, and the flow rate of the first carrier gas is 30sccm-100sccm. The conditions for the second vapor-phase deposition reaction include: a deposition temperature of 1200℃-1450℃, a deposition pressure of 30mbar-300mbar, and a deposition duration of 5h-20h. In the second vapor-phase deposition reaction, a second carrier gas, which is argon, is also introduced into the deposition furnace along with the second gas and hydrogen, and the flow rate of the second carrier gas is 50sccm-150sccm.

[0040] In one example, the second gas is trichloromethylsilane.

[0041] In one example, in step S2, the first temperature T1 is 1200℃-1450℃ (e.g., 1200℃, 1230℃, 1250℃, 1280℃, 1300℃, 1330℃, 1350℃, 1380℃, 1400℃, 1430℃ or 1450℃).

[0042] In one example, in step S2, the time required to raise the temperature to the first temperature T1 is 1h-3h (e.g., 1h, 1.3h, 1.5h, 1.8h, 2h, 2.3h, 2.5h, 2.8h or 3h).

[0043] According to one specific embodiment, in step S2, the first temperature T1 is 1200℃-1450℃ (e.g., 1200℃, 1250℃, 1300℃, 1350℃, 1400℃, or 1450℃), and the time required to heat to the first temperature T1 is 1h-3h (e.g., 1h, 1.5h, 2h, 2.5h, or 3h). Controlling the first temperature T1 and the time required to heat to the first temperature T1 within the above range can eliminate internal stress through atomic creep and dislocation rearrangement, while also facilitating the volatilization of residual volatile impurities and improving production efficiency.

[0044] In one instance, the inert gas used for purging is argon.

[0045] In one example, the volumetric flow rate of the inert gas used for purging is 50 L / min to 100 L / min (e.g., 50 L / min, 55 L / min, 60 L / min, 65 L / min, 70 L / min, 75 L / min, 80 L / min, 85 L / min, 90 L / min, 95 L / min, or 100 L / min). Controlling the volumetric flow rate of the inert gas during purging within this range creates positive pressure, ensuring that any minor furnace leakage is a protective outward overflow rather than air infiltration, thus preventing oxidation during high-temperature annealing. Simultaneously, it results in a more uniform furnace temperature, ensuring that the substrate material is treated under identical temperature conditions, improving process consistency and stability.

[0046] In one example, the acid solution is a hydrofluoric acid solution, and the weight percentage of hydrofluoric acid in the hydrofluoric acid solution is 5%-20% (e.g., 5%, 8%, 10%, 13%, 15%, 18%, or 20%). Controlling the weight percentage of hydrofluoric acid in the hydrofluoric acid solution within the above range can achieve a sufficient and controllable reaction rate, thereby efficiently completing a good cleaning effect within a controllable time.

[0047] In one example, the duration of the first contact is 30-60 minutes (e.g., 30 minutes, 35 minutes, 40 minutes, 45 minutes, 50 minutes, 55 minutes, or 60 minutes). Controlling the duration of the first contact within this range ensures a sufficiently wide process window for complete removal of the oxide layer from the substrate material surface, guaranteeing stable removal results even with fluctuations in time or oxide layer thickness, while minimizing time and improving production time while ensuring effectiveness.

[0048] In one instance, the protective atmosphere is hydrogen or argon.

[0049] In one example, the high-temperature annealing conditions include: an annealing temperature of 800℃-1000℃ and an annealing duration of 60min-120min (e.g., 60min, 65min, 70min, 75min, 80min, 85min, 90min, 95min, 100min, 105min, 110min, 115min, or 120min). Controlling these high-temperature annealing conditions can eliminate internal stress in the substrate material. When the annealing temperature is too high and / or the duration is too long, it can easily lead to degradation of the substrate material's properties, affecting the structural stability of the silicon-based material; when the annealing temperature is too low and / or the duration is too short, water molecules or carbon-hydrogen bonds on the substrate material surface are not completely removed.

[0050] In one example, the substrate material comprises monocrystalline silicon and / or polycrystalline silicon.

[0051] The second invention provides a silicon-based material prepared by the preparation method described in the first aspect of the invention.

[0052] The silicon-based material prepared by the preparation method described in the first aspect of the present invention can achieve a continuous change in the silicon content of the coating, thereby enabling a continuous transition between the difference in the coefficient of thermal expansion between the coating and the substrate material. This improves the difference in the degree of thermal expansion between the coating and the substrate material at high temperatures and the generation of a large amount of thermal stress during cooling, which causes the coating to crack or peel off due to stress concentration, thereby improving the overall structural consistency and structural stability of the silicon-based material.

[0053] In one instance, such as Figure 1 and Figure 2 As shown, the silicon-based material 1 includes a substrate material 11, a first coating 12 located on the surface of the substrate material, and a second coating 13 located on the surface of the first coating 12. The first coating is composed of elemental silicon and elemental carbon. The surface of the first coating closest to the substrate material is the first surface, and the surface of the first coating closest to the second coating is the second surface. In the thickness direction of the silicon-based material, the molar ratio of elemental silicon to elemental carbon in the first coating continuously changes with the thickness of the first coating, and the molar ratio of elemental silicon to elemental carbon in the first surface is greater than the molar ratio of elemental silicon to elemental carbon in the second surface.

[0054] In one example, the molar percentage of silicon in the first coating is 100%-50% (e.g., 100%, 95%, 90%, 85%, 80%, 75%, 70%, 65%, 60%, 55%, or 50%). It is understood that the molar percentage of silicon in the first coating varies continuously within the range of 100%-50% along the thickness direction of the first coating.

[0055] In one example, the second coating comprises elemental silicon and elemental carbon, wherein the molar ratio of the elemental silicon to the elemental carbon in the second coating is (0.9-1.1):1 (e.g., 0.9:1, 0.93:1, 0.95:1, 0.98:1, 1:1, 1.03:1, 1.05:1, 1.08:1 or 1.1:1).

[0056] In one example, the thickness of the first coating is 30 μm to 60 μm (e.g., 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, 55 μm or 60 μm).

[0057] In one example, the thickness of the second coating is 50 μm to 250 μm (e.g., 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, 110 μm, 120 μm, 130 μm, 140 μm, 150 μm, 160 μm, 1170 μm, 180 μm, 190 μm, 200 μm, 210 μm, 220 μm, 230 μm, 240 μm or 250 μm).

[0058] The present invention will be described in detail below through embodiments. The embodiments described herein are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0059] The following examples illustrate the preparation method of the silicon-based material of the present invention and the silicon-based material obtained therefrom.

[0060] Example 1 Preparation of silicon-based materials: S1: Pretreatment: The substrate material (single crystal silicon) is first contacted with hydrofluoric acid solution (for 60 min), and then high-temperature annealing is performed in a deposition furnace under a protective atmosphere (argon) to obtain a precursor with an activated surface; wherein, the conditions of the high-temperature annealing include: annealing temperature of 1000℃ and annealing duration of 90 min. S2: Exhausting: The deposition furnace is heated to the first temperature T1 (1300℃) while purging the deposition furnace with an inert gas (argon); wherein, the time required to heat up to the first temperature T1 is 2 hours, and the volumetric flow rate of the inert gas for purging is 60L / min. S3: First vapor deposition reaction: A first gas (trichloromethylsilane) and hydrogen are simultaneously introduced into the deposition furnace to contact the precursor with the activated surface, and a first vapor deposition reaction is performed to form a first coating on the surface of the precursor with the activated surface, thereby obtaining a silicon-based material intermediate; wherein, the first gas includes a silicon source gas and a carbon source gas, the flow rate of the first gas into the deposition furnace is V1, in sccm, and V1 continuously increases with time, the flow rate of hydrogen into the deposition furnace is V2, in sccm, and V2 continuously decreases with time, and V1 and V2 satisfy the following relationship: V1 + V2 = 200; S4: Second vapor deposition reaction: A second gas (trichloromethylsilane) and hydrogen are introduced into the deposition furnace and brought into contact with the silicon-based material intermediate to perform a second vapor deposition reaction, forming a second coating on the surface of the silicon-based material intermediate; wherein, the second gas includes silicon source gas and carbon source gas, and the ratio of the flow rate of the second gas to the flow rate of hydrogen in the deposition furnace is approximately 5:1.

[0061] The initial flow rate V1 of the first gas introduced into the deposition furnace is 10 sccm, and the rate of change of V1 is 26 sccm / h. The initial flow rate V2 of the hydrogen introduced into the deposition furnace is 190 sccm, and the rate of change of V2 is 26 sccm / h. When V1 gradually increases to 166 sccm over time, the first gas-phase deposition reaction ends. The conditions for the first gas-phase deposition reaction include: a deposition temperature of 1300℃, a deposition pressure of 100 mbar, and a deposition duration of 6 hours. Along with the first gas and hydrogen, a first carrier gas, argon, is also introduced into the deposition furnace at a flow rate of 80 sccm. The conditions for the second vapor deposition reaction include: a deposition temperature of 1350°C, a deposition pressure of 120 mbar, and a deposition duration of 5 h; a second carrier gas, argon, is also introduced into the deposition furnace along with the second gas and hydrogen, and the flow rate of the second carrier gas is 80 sccm; in the second vapor deposition reaction, the volumetric flow rate of the second gas is 167 sccm, and the volumetric flow rate of hydrogen is 33 sccm.

[0062] In the prepared silicon-based material, the molar percentage of silicon in the first coating continuously varies in the range of 97%-50% in the thickness direction of the first coating, and the thickness of the first coating is 50 μm; the composition of the second coating includes elemental silicon and elemental carbon, the molar ratio of the elemental silicon to the elemental carbon in the second coating is 1:1, and the thickness of the second coating is 100 μm.

[0063] Example 2 group This set of examples illustrates the effects of changing the initial flow rate of the first gas introduced into the deposition furnace.

[0064] Example 2a The process was carried out in accordance with Example 1, except that the initial flow rate of the first gas into the deposition furnace was 5 sccm. In the thickness direction of the first coating, the molar percentage of silicon in the first coating continuously varied in the range of 97.3%-50%, and the thickness of the first coating was 47 μm.

[0065] Example 2b The process was carried out in accordance with Example 1, except that the initial flow rate of the first gas into the deposition furnace was 35 sccm, and the molar percentage of silicon in the first coating continuously varied in the range of 90%-50% in the thickness direction of the first coating, and the thickness of the first coating was 44 μm.

[0066] Example 3 Group This set of examples illustrates the effects of a change in the flow rate of the first gas introduced into the deposition furnace at the end of the first vapor deposition reaction.

[0067] Example 3a The process was carried out in accordance with Example 1, except that when V1 gradually increased to 120 sccm over time, the first vapor deposition reaction ended. In the thickness direction of the first coating, the molar percentage of silicon in the first coating continued to change in the range of 90%-57%, and the thickness of the first coating was 45 μm.

[0068] Example 3b The process was carried out in accordance with Example 1, except that when V1 gradually increased to 130 sccm over time, the first vapor deposition reaction ended. In the thickness direction of the first coating, the molar percentage of silicon in the first coating continued to change in the range of 90%-56%, and the thickness of the first coating was 47 μm.

[0069] Example 4 group This set of examples illustrates the effects of changes in continuously increasing and continuously decreasing rates of change.

[0070] Example 4a This set of embodiments is based on Embodiment 1, except that the continuously increasing rate of change is 20 sccm / h, the continuously decreasing rate of change is 20 sccm / h, and the thickness of the first coating is 70 μm.

[0071] Example 4b This set of embodiments is based on Embodiment 1, except that the continuously increasing rate of change is 60 sccm / h, the continuously decreasing rate of change is 60 sccm / h, and the thickness of the first coating is 23 μm.

[0072] Example 5 group This set of examples illustrates the effects of changes in the reaction deposition temperature of the first deposition reaction.

[0073] This embodiment group is carried out with reference to Embodiment 1, except that the deposition temperature of the first deposition reaction is changed, as detailed in Table 1-1.

[0074] Example 6 group This set of examples illustrates the effects of changes in the reaction deposition pressure of the first deposition reaction.

[0075] This embodiment group is carried out with reference to Embodiment 1, except that the deposition pressure of the first deposition reaction is changed, as detailed in Table 1-1.

[0076] Table 1-1 Example 7 group This set of examples illustrates the effects of changes in the reaction deposition temperature of the second deposition reaction.

[0077] This embodiment group is carried out with reference to Embodiment 1, except that the deposition temperature of the second deposition reaction is changed, as detailed in Tables 1-2.

[0078] Example 8 group This set of examples illustrates the effects of changes in the reaction deposition pressure of the second deposition reaction.

[0079] This embodiment group is carried out with reference to Embodiment 1, except that the deposition pressure of the second deposition reaction is changed, as detailed in Tables 1-2.

[0080] Table 1-2 Comparative Example 1 The process was carried out in accordance with Example 1, except that the flow rate V1 of the first gas entering the deposition furnace was kept constant at 10 sccm and the flow rate V2 of hydrogen entering the deposition furnace was kept constant at 190 sccm throughout the first gas phase deposition process.

[0081] Comparative Example 2 The process was carried out in accordance with Example 1, except that the flow rate V1 of the first gas entering the deposition furnace was kept constant at 50 sccm and the flow rate V2 of hydrogen entering the deposition furnace was kept constant at 120 sccm throughout the first gas phase deposition process.

[0082] Comparative Example 3 The same procedure was performed as in Example 1, except that the rate of continuous increase of V1 was 20 sccm / h, and the rate of continuous decrease of V2 was 40 sccm / h.

[0083] Test case The silicon-based materials prepared in the examples and comparative examples were tested as follows.

[0084] 1. Bonding strength test The specific test method for bonding strength can be referred to the method described in GB / T 31541-2015.

[0085] 2. Deformation test Deformation testing can be performed directly by placing the test sample in a CMM coordinate measuring machine.

[0086] The results are recorded in Table 2.

[0087] Table 2 As can be seen from Table 2, by comparing the comparative examples and the embodiments, the bonding strength of the silicon-based material prepared in the embodiments is significantly improved and the deformation is significantly reduced. This indicates that by controlling the sum of the flow rates V1 of the first gas and V2 of the hydrogen gas in the first vapor deposition reaction, as well as the changing trends of V1 and V2, the structural consistency and structural stability of the silicon-based material prepared are improved.

[0088] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.< / si>

Claims

1. A method for preparing a silicon-based material, characterized in that, The preparation method Includes the following steps: S1： Pretreatment: The substrate material is first contacted with an acid solution, and then annealed at high temperature in a deposition furnace under a protective atmosphere to obtain a precursor with an activated surface; S2: Exhaust: Heat the deposition furnace to the first temperature T1, and purge the deposition furnace with inert gas at the same time; S3: First vapor deposition reaction: A first gas and hydrogen are simultaneously introduced into a deposition furnace to contact the precursor with the activated surface, and a first vapor deposition reaction is performed to form a first coating on the surface of the precursor with the activated surface, thereby obtaining a silicon-based material intermediate; wherein, the first gas includes silicon source gas and carbon source gas, the flow rate of the first gas into the deposition furnace is V1, in sccm, and V1 continuously increases with time, the flow rate of hydrogen into the deposition furnace is V2, in sccm, and V2 continuously decreases with time, and V1 and V2 satisfy the following relationship: V1 + V2 = 200; S4: Second vapor deposition reaction: A second gas and hydrogen are introduced into a deposition furnace and brought into contact with the silicon-based material intermediate to perform a second vapor deposition reaction, forming a second coating on the surface of the silicon-based material intermediate; wherein, the second gas includes silicon source gas and carbon source gas, and the ratio of the flow rate of the second gas into the deposition furnace to the flow rate of hydrogen into the deposition furnace is (1-60):

1.

2. The preparation method according to claim 1, wherein, The flow rate V1 of the first gas introduced into the deposition furnace is 5 sccm-170 sccm; And / or, the flow rate V2 of the hydrogen gas introduced into the deposition furnace is 195 sccm-30 sccm; And / or, when V1 gradually increases to 120 sccm-170 sccm over time, the first vapor deposition reaction ends; And / or, the first gas is trichloromethylsilane.

3. The preparation method according to claim 1 or 2, wherein, The conditions for the first vapor deposition reaction include: deposition temperature of 1200℃-1450℃, deposition pressure of 30mbar-300mbar, and deposition duration of 3h-10h. And / or, the conditions for the second vapor deposition reaction include: a deposition temperature of 1200℃-1450℃, a deposition pressure of 30mbar-300mbar, and a deposition duration of 5h-20h; And / or, the second gas is trichloromethylsilane; And / or, the flow rate of the second gas into the deposition furnace is the same as the flow rate of the first gas at the end of the first vapor deposition reaction; And / or, in the second vapor deposition reaction, the flow rate of hydrogen entering the deposition furnace is the same as the flow rate of hydrogen at the end of the first vapor deposition reaction.

4. The preparation method according to claim 1, wherein, The first temperature T1 is 1200℃-1450℃; And / or, in step S2, the time required to raise the temperature to the first temperature T1 is 1h-3h; And / or, the inert gas used for purging is argon; And / or, the volumetric flow rate of the inert gas used for purging is 50 L / min to 100 L / min.

5. The preparation method according to claim 1, wherein, The acid solution is a hydrofluoric acid solution, and the hydrofluoric acid in the hydrofluoric acid solution accounts for 5%-20% by weight. And / or, the duration of the first contact is 30 min to 60 min.

6. The preparation method according to claim 1, wherein, The protective atmosphere is hydrogen or argon; And / or, the conditions for the high-temperature annealing include: an annealing temperature of 800℃-1000℃ and an annealing duration of 10min-60min.

7. The preparation method according to claim 1, wherein, The substrate material comprises monocrystalline silicon and / or polycrystalline silicon; And / or, in the first gas phase deposition reaction, a first carrier gas is also introduced into the deposition furnace along with the first gas and hydrogen. The first carrier gas is argon and the flow rate of the first carrier gas is 30 sccm-100 sccm. And / or, in the second vapor deposition reaction, a second carrier gas, which is argon, is also introduced into the deposition furnace along with the second gas and hydrogen, and the flow rate of the second carrier gas is 50 sccm-150 sccm.

8. A silicon-based material, characterized in that, The silicon-based material is prepared by the preparation method according to any one of claims 1-7.

9. The silicon-based material according to claim 8, wherein, The silicon-based material includes a substrate material, a first coating on the surface of the substrate material, and a second coating on the surface of the first coating. The first coating is composed of elemental silicon and elemental carbon. The surface of the first coating closest to the substrate material is the first surface, and the surface of the first coating closest to the second coating is the second surface. In the thickness direction of the silicon-based material, the molar ratio of elemental silicon to elemental carbon in the first coating continuously changes with the thickness of the first coating, and the molar ratio of elemental silicon to elemental carbon in the first surface is greater than the molar ratio of elemental silicon to elemental carbon in the second surface.

10. The silicon-based material according to claim 9, wherein, The molar percentage of silicon in the first coating is 100%-50%; And / or, the composition of the second coating includes elemental silicon and elemental carbon, wherein the molar ratio of the elemental silicon to the elemental carbon in the second coating is (0.9-1.1):1; And / or, the thickness of the first coating is 30μm-60μm; And / or, the thickness of the second coating is 50μm-250μm.

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