A graphite semiconductor device and its fabrication method

Abstract

This invention discloses a graphite semiconductor device and its fabrication method, comprising the following steps: Step 1: providing a graphite substrate, heating it to 1700-2200℃ under a first low-pressure condition, and introducing a carbon-containing precursor gas for high-temperature pyrolysis deposition, so that pyrolytic carbon is deposited on the surface of the graphite substrate and penetrates into the graphite microporous structure to form a pyrolytic graphite transition layer continuously bonded to the graphite substrate; Step 2: after the formation of the pyrolytic graphite transition layer, placing it in a SiC chemical vapor deposition reaction environment, heating it to 1200-1500℃ under a second low-pressure condition, and introducing a silicon-containing precursor gas and a carbon-containing precursor gas for reaction deposition, so that SiC is deposited on the surface of the pyrolytic graphite transition layer to form a SiC main coating; the transition layer not only adheres to the graphite surface, but also penetrates into the interior of the graphite microporous structure to form a continuous bonded structure, thereby improving the density and structural stability of the substrate surface layer, and realizing a stable interface transition and stress relief between the graphite substrate and the SiC main coating.

Description

Technical Field

[0001] This invention relates to the field of semiconductor technology, and in particular to a graphite semiconductor device and its fabrication method. Background Technology

[0002] In semiconductor epitaxial manufacturing, especially in epitaxial growth processes such as MOCVD, graphite-based components are widely used as substrate support structures and heating elements. Their thermal stability, thermal conductivity uniformity, and high-temperature structural stability directly affect the growth quality and film uniformity of epitaxial materials. Because epitaxial reaction environments are typically high-temperature, corrosive, and subject to frequent thermal cycling, graphite substrates are easily corroded, flaked, and degraded due to long-term exposure to complex chemical environments. Therefore, depositing silicon carbide (SiC) coatings on graphite substrates to enhance their corrosion resistance, high-temperature performance, and lifespan has become an important technological direction in the manufacturing of core components for semiconductor equipment.

[0003] In existing technologies, chemical vapor deposition (CVD) is commonly used to directly deposit SiC coatings on the surface of graphite substrates to improve the corrosion resistance and density of the graphite surface. However, due to the difference in the coefficients of thermal expansion between the graphite substrate and the SiC material, significant thermal stress can easily be generated at the interface during high-temperature deposition and subsequent thermal cycling. When the stress concentration exceeds the interfacial bonding strength, it can easily lead to coating cracking, interfacial peeling, or even pitting failure, resulting in the exposure of the graphite substrate and corrosion, thereby shortening the service life of the component.

[0004] Therefore, how to improve the interfacial bonding stability between SiC coating and graphite substrate and reduce the risk of cracking caused by thermal stress concentration has become a key technical problem that needs to be solved in the existing technology. Summary of the Invention

[0005] The purpose of this invention is to provide a graphite semiconductor device and its preparation method, thereby solving the above-mentioned technical problems.

[0006] To achieve this objective, the present invention adopts the following technical solution: A method for fabricating a graphite semiconductor device includes the following steps: Step 1: Provide a graphite matrix, heat it to 1700-2200℃ under a first low-pressure condition, and introduce a carbon-containing precursor gas for high-temperature pyrolysis deposition, so that pyrolytic carbon is deposited on the surface of the graphite matrix and penetrates into the graphite microporous structure to form a pyrolytic graphite transition layer that is continuously bonded to the graphite matrix. Step 2: After the pyrolytic graphite transition layer is formed, it is placed in a SiC chemical vapor deposition reaction environment, heated to 1200-1500℃ under a second low pressure condition, and silicon-containing precursor gas and carbon-containing precursor gas are introduced to react and deposit, so that SiC is deposited on the surface of the pyrolytic graphite transition layer to form a SiC main coating.

[0007] Optionally, the first low-pressure condition is 1 to 100 Pa, and the heating rate is 1 to 5 °C / min.

[0008] Optionally, the thickness of the pyrolytic graphite transition layer is 5 to 10 μm, wherein a 0 to 10 μm penetration bonding region is formed on the upper surface of the pyrolytic graphite transition layer; Along the inward direction from the surface of the graphite matrix, the pyrolytic carbon permeation concentration in the permeation bonding region gradually decreases.

[0009] Optionally, the thickness of the formed SiC main coating is 50–150 μm.

[0010] Optionally, in step two, during the SiC main coating deposition process, the flow ratio of silicon-containing precursor gas to carbon-containing precursor gas is 1:1 to 1.5:1, and the reaction time is 0.5 to 10 hours.

[0011] Optionally, the specific process of step one is as follows: A graphite substrate is provided, the surface of the graphite substrate to be deposited is cleaned, and the graphite substrate is loaded onto a support fixture in a pyrolysis deposition reaction chamber, with the surface to be deposited facing the mainstream area of ​​the reaction gas. The reaction chamber is evacuated to create a low-pressure environment of 1-100 Pa, and the residual oxygen content is reduced by replacing it with an inert gas, thereby establishing stable pyrolysis deposition reaction conditions. The graphite substrate is heated at a preset heating rate under the low-pressure environment to a temperature of 1700-2200℃, and the temperature is kept at a uniform temperature to form a first deposition temperature zone on the surface of the graphite substrate. Under the conditions of the graphite matrix being at 1700-2200℃ and maintaining the low-pressure environment, a carbon-containing precursor gas is introduced into the reaction chamber, causing the carbon-containing precursor gas to undergo a pyrolysis reaction under high-temperature conditions, and a portion of the pyrolytic carbon is deposited on the surface of the graphite matrix to form a pyrolytic graphite transition layer.

[0012] Optionally, during the continuous deposition of pyrolytic carbon, another portion of the pyrolytic carbon permeates and deposits into the microporous structure of the graphite matrix, thereby forming a permeation bonding zone on the surface of the graphite matrix that is bonded to the interface of the graphite matrix.

[0013] Optionally, the specific process of step two is as follows: After the pyrolytic graphite transition layer is formed, the graphite matrix with the pyrolytic graphite transition layer is transferred to the SiC chemical vapor deposition reaction chamber, and the pyrolytic graphite transition layer is loaded and positioned as the surface to be deposited, so that it is exposed to the mainstream area of ​​the reaction gas. The SiC chemical vapor deposition reaction chamber is evacuated to create a low-pressure environment of 1-100 Pa within the chamber. Under the condition of maintaining the low pressure environment, the graphite substrate with the pyrolytic graphite transition layer is heated to 1200-1500°C at a preset heating rate, and the temperature is kept at a uniform temperature so that a second deposition temperature zone is formed on the surface of the pyrolytic graphite transition layer. Within the second deposition temperature zone, silicon-containing precursor gas and carbon-containing precursor gas are introduced into the reaction chamber, causing them to undergo a gas-phase reaction on the surface of the pyrolytic graphite transition layer to generate SiC, and forming an initial SiC deposition layer on the surface of the pyrolytic graphite transition layer.

[0014] Optionally, during the SiC deposition process, by controlling the introduction rate of the silicon-containing precursor gas and the carbon-containing precursor gas or by adopting a staged gas supply method, SiC preferentially forms a continuous and dense bonding interface on the surface of the pyrolytic graphite transition layer. Subsequently, a SiC main coating is continuously deposited to form an interface transition structure between the pyrolytic graphite transition layer and the SiC main coating.

[0015] The present invention also provides a graphite semiconductor device, which is prepared by the method described above, wherein the graphite semiconductor device comprises: Graphite matrix; A pyrolytic graphite transition layer is formed on the surface of the graphite matrix; The infiltration bonding region is formed by pyrolytic carbon infiltrating into the microporous structure of the graphite matrix; The SiC main coating is formed on the surface of the pyrolytic graphite transition layer.

[0016] Compared with existing technologies, this invention has the following advantages: First, a graphite substrate is provided and heated to 1700-2200℃ under low pressure. A carbon-containing precursor gas is then introduced for high-temperature pyrolysis deposition, allowing pyrolytic carbon to deposit on the surface of the graphite substrate while simultaneously penetrating into the microporous structure of the graphite, forming a pyrolytic graphite transition layer continuously bonded to the substrate on the graphite surface. Then, after the pyrolytic graphite transition layer is formed, it is placed in a SiC chemical vapor deposition reaction environment and heated to 1200-1100℃ under low pressure. At 500℃, silicon-containing precursor gas and carbon-containing precursor gas are introduced to react and deposit SiC on the surface of the pyrolytic graphite transition layer, forming a SiC main coating. This constructs a hierarchical composite structure of graphite matrix, pyrolytic graphite transition layer, and SiC main coating. The transition layer not only adheres to the graphite surface but also penetrates into the microporous structure of graphite to form a continuous bond structure, thereby improving the density and structural stability of the matrix surface and achieving a stable interface transition and stress relief between the graphite matrix and the SiC main coating. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] The structures, proportions, sizes, etc., shown in the accompanying drawings of this specification are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed in the specification, and are not intended to limit the conditions under which the present invention can be implemented. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportions, or adjustments to the size, without affecting the effects and objectives that the present invention can produce, should still fall within the scope of the technical content disclosed in the present invention.

[0019] Figure 1 This is a schematic flowchart of the fabrication method of the graphite semiconductor device in this embodiment. Detailed Implementation

[0020] To make the objectives, features, and advantages of this invention more apparent and understandable, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described below are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0021] In the description of this invention, it should be understood that the terms "upper," "lower," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. It should be noted that when a component is considered to be "connected" to another component, it can be directly connected to the other component or there may be a component positioned centrally in the connection.

[0022] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0023] Example 1: This invention provides a method for fabricating a graphite semiconductor device, comprising the following steps: Step 1: Provide a graphite matrix, heat it to 1700-2200℃ under initial low-pressure conditions, and introduce a carbon-containing precursor gas for high-temperature pyrolysis deposition. This allows pyrolytic carbon to deposit on the surface of the graphite matrix and penetrate into the graphite microporous structure, forming a pyrolytic graphite transition layer continuously bonded to the graphite matrix. The selected graphite matrix has a thermal expansion coefficient of 4.0 × 10⁻⁶ / K, a bulk density of 1.85 g / cm⁻³, and a total ash content of < 10 ppm. The carbon source gas includes, but is not limited to, CH₄, C₂H₆, and C₃H₆.

[0024] It should be noted that by heating the graphite matrix to 1700-2200℃ under the first low-pressure condition and introducing carbon-containing precursor gas for high-temperature pyrolysis deposition, the carbon-containing precursor undergoes a cracking reaction in a high-temperature environment, generating active carbon species that are deposited on the surface of the graphite matrix.

[0025] Because the deposition process takes place in a low-pressure, high-temperature environment, gas molecules possess strong diffusion capabilities, allowing them to penetrate the microporous structure of the graphite substrate surface and deposit. This not only forms a pyrolytic carbon deposition layer on the graphite substrate surface but also creates a penetration bonding zone of a certain depth, resulting in a continuous bonding structure between the pyrolytic graphite transition layer and the graphite substrate. This continuous bonding structure improves the density of the graphite substrate surface layer and enhances the interfacial foundation for subsequent deposition layers, providing a stable transition interface for the SiC main coating at the structural level.

[0026] Step 2: After the pyrolytic graphite transition layer is formed, it is placed in a SiC chemical vapor deposition reaction environment. Under a second low-pressure condition, the temperature is raised to 1200-1500℃, and silicon-containing precursor gas and carbon-containing precursor gas are introduced to react and deposit, allowing SiC to be deposited on the surface of the pyrolytic graphite transition layer to form the SiC main coating. The Si source includes, but is not limited to, SiCl4, MTS, SiHCl3, etc.

[0027] It should be noted that, since the pyrolytic graphite transition layer has formed a continuous bond structure with the graphite matrix, and its surface density and structural stability are better than those of the original graphite surface, SiC can form a more uniform and stable interface structure when deposited on its surface. This reduces the interface stress concentration caused by the difference in thermal expansion between graphite and SiC materials, thereby improving the coating bonding strength and crack resistance.

[0028] The working principle of this invention is as follows: First, a graphite substrate is provided and heated to 1700-2200℃ under low pressure. A carbon-containing precursor gas is introduced for high-temperature pyrolysis deposition, allowing pyrolytic carbon to deposit on the graphite substrate surface while simultaneously penetrating into the graphite microporous structure, forming a pyrolytic graphite transition layer that is continuously bonded to the substrate on the graphite surface. Then, after the pyrolytic graphite transition layer is formed, it is placed in a SiC chemical vapor deposition reaction environment and heated to 1200-1500℃ under low pressure. A silicon-containing precursor gas and a carbon-containing precursor gas are introduced for reaction deposition, allowing SiC to be deposited on the surface of the pyrolytic graphite transition layer to form a SiC main coating. This constructs a hierarchical composite structure of graphite substrate—pyrolytic graphite transition layer—SiC main coating. The transition layer not only adheres to the graphite surface but also penetrates into the graphite microporous structure to form a continuous bond, thereby improving the density and structural stability of the substrate surface and achieving a stable interface transition and stress relief between the graphite substrate and the SiC main coating.

[0029] In this embodiment, the first low-pressure condition is 1–100 Pa, and the heating rate is 1–5 °C / min. High-temperature pyrolysis deposition under low pressure improves the diffusion ability of carbon-containing precursor gas on the graphite matrix surface, making it easier for the gas to enter the microporous structure of graphite and participate in the reaction, thereby promoting the infiltration and deposition of pyrolytic carbon. Simultaneously, controlling the heating rate within the range of 1–5 °C / min avoids thermal stress concentration or excessive local temperature differences in the graphite matrix during rapid heating, helping to maintain the structural stability of the graphite matrix.

[0030] In this embodiment, the thickness of the pyrolytic graphite transition layer is 5-10 μm, wherein a 0-10 μm penetration bonding region is formed on the upper surface of the pyrolytic graphite transition layer; the pyrolytic carbon penetration concentration in the penetration bonding region gradually decreases along the direction inward from the graphite matrix surface.

[0031] It should be noted that this structure allows the pyrolytic graphite transition layer to not only exist as a surface deposition layer, but also form a gradient-distributed infiltration structure on the surface of the graphite matrix, thereby constructing a continuous transition structure composed of "high-concentration pyrolytic layer - gradient infiltration zone - graphite matrix". This gradient structure can achieve stress relief and structural transition at the interface, reduce the risk of thermal stress concentration caused by abrupt interface changes, enhance interfacial bonding strength, and improve the adhesion stability of the subsequent SiC main coating.

[0032] In this embodiment, the thickness of the formed SiC main coating is 50–150 μm. By controlling the deposition thickness within this range, a balance can be achieved between the coating structure stability and thermal shock resistance while ensuring sufficient protection of the graphite substrate.

[0033] In this embodiment, during step two, the flow ratio of silicon-containing precursor gas to carbon-containing precursor gas is 1:1 to 1.5:1, and the reaction time is 0.5 to 10 hours.

[0034] It should be noted that by controlling the flow ratio of silicon source to carbon source, the stoichiometric balance during the SiC deposition process can be adjusted to avoid the formation of silicon-rich or carbon-rich phases, thereby improving the purity and structural density of the coating. At the same time, controlling the reaction time within the range of 0.5 to 10 hours allows the SiC main coating to grow gradually and form a continuous coverage structure, avoiding stress concentration or structural defects caused by excessively rapid deposition, which is conducive to the formation of a uniform and stable outer protective structure.

[0035] In this embodiment, the specific process of step one is as follows: S11 provides a graphite substrate and cleans the surface of the graphite substrate to be deposited, removing surface dust, particles, and loose attachments. The graphite substrate is then loaded onto a support fixture in the pyrolysis deposition reaction chamber, so that the surface to be deposited faces the mainstream area of ​​the reaction gas. This facilitates uniform coverage of the deposition area by the reaction gas, improves deposition uniformity, and provides favorable airflow path conditions for the subsequent entry of pyrolytic carbon into the graphite microporous structure.

[0036] S12, the reaction chamber is evacuated to create a low-pressure environment of 1-100 Pa, and the residual oxygen content is reduced by replacing it with an inert gas, thereby establishing stable pyrolysis deposition reaction conditions.

[0037] S13, under low pressure, the graphite substrate is heated at a preset heating rate to a temperature of 1700-2200℃, and the temperature is kept at a constant temperature to form the first deposition temperature zone on the surface of the graphite substrate; the first deposition temperature zone is a stable high-temperature pyrolysis deposition temperature zone. By controlling the heating rate and temperature equalization process, the thermal stress concentration caused by temperature difference can be reduced, making the temperature distribution on the surface of the graphite matrix more uniform, thus providing stable thermal field conditions for the stable pyrolysis and uniform deposition of the subsequent carbon-containing precursor gas.

[0038] S14, under the condition that the graphite matrix is ​​at 1700-2200℃ and the low pressure environment is maintained, carbon-containing precursor gas is introduced into the reaction chamber, so that the carbon-containing precursor gas undergoes a pyrolysis reaction under high temperature conditions, and a part of the pyrolytic carbon is deposited on the surface of the graphite matrix to form a pyrolytic graphite transition layer.

[0039] The pyrolytic graphite transition layer and the graphite matrix are highly compatible in terms of lattice structure and chemical composition, which enables the formation of a continuous bond structure at the interface and improves the interface stability.

[0040] S15, during the continuous deposition of pyrolytic carbon, another part of the pyrolytic carbon permeates and deposits into the microporous structure of the graphite matrix, thereby forming a permeation bonding zone on the surface of the graphite matrix that is bonded to the graphite matrix interface.

[0041] It should be noted that this penetration bonding region enables the pyrolytic graphite transition layer not only to adhere to the surface of the graphite matrix, but also to form an embedded continuous bonding structure with the graphite matrix at the microscopic level. This enhances the overall bonding strength of the interface and constructs a gradient transition structure, which is beneficial for mitigating the interfacial stress generated during subsequent SiC deposition and thermal cycling, thereby improving the overall structural stability of the device.

[0042] In this embodiment, the specific process of step two is as follows: S21, after the pyrolytic graphite transition layer is formed, the graphite matrix with the pyrolytic graphite transition layer is transferred to the SiC chemical vapor deposition reaction chamber, and the pyrolytic graphite transition layer is loaded and positioned as the surface to be deposited, so that it is exposed to the mainstream area of ​​the reaction gas.

[0043] S22, the SiC chemical vapor deposition reaction chamber is evacuated to create a low-pressure environment of 1-100 Pa, and inert gas is introduced to replace it to reduce the residual oxygen content, thereby establishing a stable SiC deposition reaction environment. It can effectively avoid oxidation reactions under high temperature conditions, thus ensuring the purity of the SiC deposition process; at the same time, the low-pressure environment is conducive to improving the mass transfer efficiency of silicon-containing precursor gas and carbon-containing precursor gas, so that they can react uniformly on the surface of the pyrolytic graphite transition layer.

[0044] S23, under the condition of maintaining a low pressure environment, the graphite substrate with the pyrolytic graphite transition layer is heated to 1200-1500℃ at a preset heating rate, and the temperature is kept at a uniform temperature so that a second deposition temperature zone is formed on the surface of the pyrolytic graphite transition layer. This temperature range is the reaction temperature range required for the SiC gas-phase reaction. By controlling the heating rate and temperature equalization process, the additional thermal stress caused by the temperature difference between the pyrolytic graphite transition layer and the graphite matrix can be reduced.

[0045] S24, silicon-containing precursor gas and carbon-containing precursor gas are introduced into the reaction chamber in the second deposition temperature zone, so that SiC is generated by gas phase reaction on the surface of pyrolytic graphite transition layer, and an initial SiC deposition layer is formed on the surface of pyrolytic graphite transition layer.

[0046] A continuous bond structure has been formed between the pyrolytic graphite transition layer and the graphite matrix. Its surface state is more stable and denser than that of the original graphite. Therefore, SiC nucleation on its surface is more uniform, which is conducive to the formation of a continuous and firmly attached initial deposition layer.

[0047] S25. During the SiC deposition process, by controlling the introduction rate of silicon-containing precursor gas and carbon-containing precursor gas or by adopting a staged gas supply method, SiC preferentially forms a continuous and dense bonding interface on the surface of the pyrolytic graphite transition layer. S26, then continued deposition to form the SiC main coating, thereby forming an interface transition structure between the pyrolytic graphite transition layer and the SiC main coating.

[0048] It should be noted that by controlling the introduction rates of silicon-containing and carbon-containing precursor gases or adopting a staged gas supply method, SiC preferentially forms a continuous and dense bonding interface on the surface of the pyrolytic graphite transition layer, thereby reducing interface porosity and structural defects. Subsequently, the SiC main coating is continuously deposited, gradually increasing its thickness and forming a complete outer protective structure. Through the above interface control and continuous deposition process, a stable interface transition structure is formed between the pyrolytic graphite transition layer and the SiC main coating, effectively mitigating interface thermal stress and improving the overall device's crack resistance and long-term service stability.

[0049] Example 2: The present invention also provides a specific method for preparing a graphite semiconductor device, which is the same as the preparation process in Example 1, except that the graphite substrate has a bulk density of 1.85 g / cm3 and a coefficient of thermal expansion of 5.0×10-6 / k.

[0050] Example 3: The present invention also provides a specific method for preparing a graphite semiconductor device, which is the same as the preparation process in Example 1, except that the reaction temperature in step 2 is set to 2200℃.

[0051] Example 4: The present invention also provides a specific method for preparing a graphite semiconductor device, which differs from Example 1 only in that the heat preservation time in step one is set to 1 hour.

[0052] Example 5: The present invention also provides a specific method for preparing a graphite semiconductor device, wherein the carbon-containing precursor gas in step one is selected as methane as the C source.

[0053] Example 6: The present invention also provides a specific method for fabricating a graphite semiconductor device, wherein the silicon-containing precursor gas in step two has an MTS source.

[0054] Example 7: The present invention also provides a specific method for preparing a graphite semiconductor device, wherein the carbon-containing precursor gas in step two is selected as methane as the C source.

[0055] Example 8: The present invention also provides a specific method for preparing a graphite semiconductor device, which differs from Example 1 only in that the flow ratio of silicon-containing precursor gas to carbon-containing precursor gas in step two is selected as 1:1.

[0056] Example 9: The present invention also provides a specific method for preparing a graphite semiconductor device, which differs from Example 1 only in that the reaction temperature in step two is 1500℃.

[0057] Example 10: The present invention also provides a specific method for preparing a graphite semiconductor device, which differs from Example 1 only in that the heat preservation time in step two is 2 hours.

[0058] Performance parameter table of graphite semiconductor devices It can be seen that increased density (Example 2) → increased bonding strength; Excessive deposition temperature (Example 3) → Increased thermal stress and cracking rate; Insufficient heat preservation time (Examples 4 and 10) → Inadequate coating density; Adjusting the Si:C ratio (Example 8) → Improved interface density; Deposition at 1500℃ (Example 9) → Optimal bonding strength.

[0059] Example 11: The present invention also provides a graphite semiconductor device, which is prepared by the method for preparing a graphite semiconductor device as described in Example 1. The graphite semiconductor device includes: Graphite matrix; A pyrolytic graphite transition layer is formed on the surface of the graphite matrix; The infiltration bonding zone is formed by pyrolytic carbon infiltrating into the microporous structure of the graphite matrix; The SiC main coating is formed on the surface of the pyrolytic graphite transition layer. The SiC main coating covers the pyrolytic graphite transition layer and constitutes the outer layer structure of the graphite semiconductor device.

[0060] The above-described embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for fabricating a graphite semiconductor device, characterized in that, Includes the following steps: Step 1: Provide a graphite matrix, heat it to 1700-2200℃ under a first low-pressure condition, and introduce a carbon-containing precursor gas for high-temperature pyrolysis deposition, so that pyrolytic carbon is deposited on the surface of the graphite matrix and penetrates into the graphite microporous structure to form a pyrolytic graphite transition layer that is continuously bonded to the graphite matrix. Step 2: After the pyrolytic graphite transition layer is formed, it is placed in a SiC chemical vapor deposition reaction environment, heated to 1200-1500℃ under a second low pressure condition, and silicon-containing precursor gas and carbon-containing precursor gas are introduced to react and deposit, so that SiC is deposited on the surface of the pyrolytic graphite transition layer to form a SiC main coating.

2. The method for fabricating a graphite semiconductor device according to claim 1, characterized in that, The first low-pressure condition is 1 to 100 Pa, and the heating rate is 1 to 5 °C / min.

3. The method for fabricating a graphite semiconductor device according to claim 1, characterized in that, The thickness of the pyrolytic graphite transition layer is 5-10 μm, wherein a 0-10 μm penetration bonding region is formed on the upper surface of the pyrolytic graphite transition layer; Along the inward direction from the surface of the graphite matrix, the pyrolytic carbon permeation concentration in the permeation bonding region gradually decreases.

4. The method for fabricating a graphite semiconductor device according to claim 1, characterized in that, The thickness of the formed SiC main coating is 50–150 μm.

5. The method for fabricating a graphite semiconductor device according to claim 1, characterized in that, In step two, during the SiC main coating deposition process, the flow ratio of silicon-containing precursor gas to carbon-containing precursor gas is 1:1 to 1.5:1, and the reaction time is 0.5 to 10 hours.

6. The method for fabricating a graphite semiconductor device according to claim 1, characterized in that, The specific process of step one is as follows: A graphite substrate is provided, the surface of the graphite substrate to be deposited is cleaned, and the graphite substrate is loaded onto a support fixture in a pyrolysis deposition reaction chamber, with the surface to be deposited facing the mainstream area of ​​the reaction gas. The reaction chamber is evacuated to create a low-pressure environment of 1-100 Pa, and the residual oxygen content is reduced by replacing it with an inert gas, thereby establishing stable pyrolysis deposition reaction conditions. The graphite substrate is heated at a preset heating rate under the low-pressure environment to a temperature of 1700-2200℃, and the temperature is kept at a uniform temperature to form a first deposition temperature zone on the surface of the graphite substrate. Under the conditions of the graphite matrix being at 1700-2200℃ and maintaining the low-pressure environment, a carbon-containing precursor gas is introduced into the reaction chamber, causing the carbon-containing precursor gas to undergo a pyrolysis reaction under high-temperature conditions, and a portion of the pyrolytic carbon is deposited on the surface of the graphite matrix to form a pyrolytic graphite transition layer.

7. The method for fabricating a graphite semiconductor device according to claim 6, characterized in that, During the continuous deposition of pyrolytic carbon, another portion of the pyrolytic carbon permeates and deposits into the microporous structure of the graphite matrix, thereby forming a permeation bonding zone on the surface of the graphite matrix that is bonded to the interface of the graphite matrix.

8. The method for fabricating a graphite semiconductor device according to claim 1, characterized in that, The specific process of step two is as follows: After the pyrolytic graphite transition layer is formed, the graphite matrix with the pyrolytic graphite transition layer is transferred to the SiC chemical vapor deposition reaction chamber, and the pyrolytic graphite transition layer is loaded and positioned as the surface to be deposited, so that it is exposed to the mainstream area of ​​the reaction gas. The SiC chemical vapor deposition reaction chamber is evacuated to create a low-pressure environment of 1-100 Pa within the chamber. Under the condition of maintaining the low pressure environment, the graphite substrate with the pyrolytic graphite transition layer is heated to 1200-1500°C at a preset heating rate, and the temperature is kept at a uniform temperature so that a second deposition temperature zone is formed on the surface of the pyrolytic graphite transition layer. Within the second deposition temperature zone, silicon-containing precursor gas and carbon-containing precursor gas are introduced into the reaction chamber, causing them to undergo a gas-phase reaction on the surface of the pyrolytic graphite transition layer to generate SiC, and forming an initial SiC deposition layer on the surface of the pyrolytic graphite transition layer.

9. The method for fabricating a graphite semiconductor device according to claim 8, characterized in that, During the SiC deposition process, by controlling the introduction rate of the silicon-containing precursor gas and the carbon-containing precursor gas or by adopting a staged gas supply method, SiC preferentially forms a continuous and dense bonding interface on the surface of the pyrolytic graphite transition layer. Subsequently, a SiC main coating is continuously deposited to form an interface transition structure between the pyrolytic graphite transition layer and the SiC main coating.

10. A graphite semiconductor device, characterized in that, The graphite semiconductor device is prepared by the method described in any one of claims 1 to 8, wherein the graphite semiconductor device comprises: Graphite matrix; A pyrolytic graphite transition layer is formed on the surface of the graphite matrix; The infiltration bonding region is formed by pyrolytic carbon infiltrating into the microporous structure of the graphite matrix; The SiC main coating is formed on the surface of the pyrolytic graphite transition layer.

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