A resistivity-tunable SiC hierarchical structure, growth method and semiconductor device

Abstract

The application discloses a SiC hierarchical structure with adjustable resistivity, a growth method and a semiconductor device, and relates to the technical field of semiconductor materials, in particular to a SiC hierarchical structure with adjustable resistivity, a growth method and a semiconductor device. The SiC hierarchical structure with adjustable resistivity comprises the following steps: according to a target resistivity interval of a SiC hierarchical structure to be prepared, a deposition parameter group is selected, the deposition parameter group comprises a deposition temperature T0, a deposition pressure P0 and a mixed gas ratio B; the mixed gas ratio B is a flow ratio of a silicon-carbon source gas, hydrogen and an inert gas; a graphite substrate is placed in a deposition chamber for high-temperature purification pretreatment, and then the deposition chamber is controlled to a pre-deposition temperature T1; the silicon-carbon source gas, the hydrogen and the inert gas are introduced into the deposition chamber according to the mixed gas ratio B, the deposition temperature T0 and the deposition pressure P0 are maintained, and a SiC hierarchical structure is deposited on the surface of the substrate; through corresponding selection of the target resistivity interval and the deposition parameter group, directional preparation of the SiC hierarchical structure in the resistivity interval is realized, which is beneficial to improving production efficiency and improving product performance.

Description

Technical Field

[0001] This invention relates to the field of semiconductor technology, and in particular to a SiC layer structure with adjustable resistivity, a growth method thereon, and a semiconductor device. Background Technology

[0002] Silicon carbide (SiC) materials possess high thermal conductivity, high critical breakdown field strength, wide bandgap, and excellent corrosion resistance, making them widely used in semiconductor process equipment, high-power electronic devices, plasma cavity components, and wafer bonding components. In these applications, the electrical performance requirements of SiC materials vary depending on the application location. For example, some bonding or support structures require low resistivity to meet conductivity or electrostatic discharge requirements, while some isolation, protection, or corrosion-resistant structures require higher resistivity to meet insulation requirements.

[0003] In existing technologies, bulk SiC materials are typically prepared using chemical vapor deposition (CVD), which involves introducing a raw material gas containing silicon and carbon sources into a deposition chamber, where it decomposes under high-temperature conditions and reacts and deposits on the substrate surface to form a SiC structure. To control the volume resistivity of SiC materials, existing processes often introduce dopants into the reaction system, allowing dopant atoms to enter the SiC lattice and alter the material's energy level structure, thereby changing the resistivity. However, for SiC components used in wafer bonding or near the wafer processing environment, dopant atoms may diffuse under high-temperature processing conditions, adversely affecting wafer purity and electrical performance.

[0004] Therefore, how to prepare SiC layered structures with a target resistivity range without relying on dopants has become a technical problem that needs to be solved. Summary of the Invention

[0005] The purpose of this invention is to provide a SiC layer structure with adjustable resistivity, a growth method, and a semiconductor device to solve the above-mentioned technical problems.

[0006] To achieve this objective, the present invention adopts the following technical solution: A method for growing SiC layered structures with tunable resistivity, comprising: Based on the target resistivity range of the SiC layer structure to be prepared, a set of deposition parameters is selected, including deposition temperature T0, deposition pressure P0, and mixed gas ratio B; the mixed gas ratio B is the flow ratio of silicon-carbon source gas, hydrogen, and inert gas. Graphite as a substrate is placed in a deposition chamber for high-temperature purification pretreatment, and then the deposition chamber is controlled to the pre-deposition temperature T1; According to the mixed gas ratio B, silicon-carbon source gas, hydrogen and inert gas are introduced into the deposition chamber to maintain the deposition temperature T0 and the deposition pressure P0, and SiC layer structure is deposited on the substrate surface.

[0007] Optionally, after depositing the SiC layer structure on the substrate surface, the method further includes: Stop supplying silicon-carbon source gas, hydrogen, and inert gas to the deposition chamber, and evacuate the deposition chamber. The deposition chamber is naturally cooled to room temperature to obtain a graphite substrate with the SiC layer structure attached. The graphite substrate is removed, and the resistivity of the SiC layer structure is tested to verify whether the resistivity of the SiC layer structure is within the target resistivity range.

[0008] Optionally, the pretreatment of placing graphite as a substrate in a deposition chamber for high-temperature purification includes: The graphite substrate is heated to 1800℃~2000℃ under an inert atmosphere and kept at a constant temperature for 4~6 hours to allow impurities on the surface of the graphite substrate to volatilize. After heating is stopped, inert gas is continuously introduced into the environment where the graphite substrate is located, and the cooling rate is controlled to be ≤50℃ / min to cool the graphite substrate. The cooled graphite substrate is fixed in the central region of the deposition chamber, and a preset distance is maintained between the surface of the graphite substrate and the gas distributor of the deposition chamber. The vacuum pump is started to evacuate the deposition chamber in stages. In the first stage, the pressure in the deposition chamber is reduced to below 10 kPa and maintained for 5 to 10 minutes. In the second stage, the vacuum is continued to be evacuated to the preset low pressure range.

[0009] Optionally, controlling the deposition chamber to the pre-deposition temperature T1 includes: The graphite substrate in the deposition chamber is heated to the pre-deposition temperature T1 at a stepped heating rate. At the pre-deposition temperature T1, inert gas is introduced into the deposition chamber and purged for 20 to 40 minutes using a pulse injection method to remove volatile impurities remaining in the deposition chamber, pipes, and the surface of the graphite substrate. During the purging process, the vacuum pump is started to pump air synchronously and the pressure in the deposition chamber is maintained at 50~80kPa.

[0010] Optionally, heating the graphite substrate in the deposition chamber to the pre-deposition temperature T1 at a stepped heating rate includes: In the first stage, the graphite substrate is heated to 800°C at a heating rate of 10°C / min and held at that temperature for 10 minutes to release the internal stress of the graphite substrate. In the second stage, the graphite substrate is heated to the pre-deposition temperature T1 at a heating rate of 5℃ / min, and the surface temperature fluctuation of the graphite substrate is controlled to not exceed ±5℃ during the heating process.

[0011] Optionally, the silicon-carbon source gas is methyltrichlorosilane, and the inert gas is argon. In the deposition parameter set, the deposition temperature T0 is 1360℃~1460℃, the deposition pressure P0 is 10kPa~18kPa, and the mixed gas ratio B includes methyltrichlorosilane flow rate of 10~43g / min, hydrogen flow rate of 42~50L / min, and argon flow rate of 45L / min.

[0012] Optionally, selecting the deposition parameter set based on the target resistivity range of the SiC layer structure to be prepared includes: Multiple preset deposition parameter groups are provided, each of which includes a corresponding deposition temperature T0, deposition pressure P0, and mixed gas ratio B; SiC layered structures were prepared using each of the preset deposition parameter sets, and the resistivity of the prepared SiC layered structures was tested to obtain the resistivity range corresponding to each of the preset deposition parameter sets. The target resistivity range is matched with the resistivity range corresponding to each preset deposition parameter group, and the matched preset deposition parameter group is selected as the deposition parameter group.

[0013] Optionally, the pre-deposition temperature T1 is a pre-stabilization temperature determined based on the deposition temperature T0, and the pre-deposition temperature T1 is equal to the deposition temperature T0, or the temperature difference between the pre-deposition temperature T1 and the deposition temperature T0 is not greater than 10℃. Before introducing the silicon-carbon source gas, hydrogen, and inert gas corresponding to the mixed gas ratio B, the deposition chamber is first purged with inert gas at the pre-deposition temperature T1, and after purging, the deposition chamber is stabilized at the deposition temperature T0.

[0014] The present invention also provides a resistivity-tunable SiC layer structure, which is prepared by the resistivity-tunable SiC layer structure growth method described above. The resistivity of the SiC layer structure is within the target resistivity range corresponding to the deposition parameter set.

[0015] The present invention also provides a semiconductor device comprising a resistivity-tunable SiC layer structure as described above.

[0016] Compared with existing technologies, this invention has the following advantages: During the growth process, firstly, based on the target resistivity range required to prepare the SiC layered structure, a set of deposition parameters corresponding to the target resistivity range is selected. This set of deposition parameters includes at least a deposition temperature T0, a deposition pressure P0, and a mixed gas ratio B consisting of the flow rates of silicon-carbon source gas, hydrogen, and inert gas. Subsequently, graphite is placed in the deposition chamber as a substrate for high-temperature purification pretreatment. After pretreatment, the deposition chamber is controlled to a pre-deposition temperature T1, ensuring the graphite substrate and the deposition chamber are in a thermally stable state suitable for reaction deposition. Then, silicon-carbon source gas, hydrogen, and inert gas are introduced into the deposition chamber according to the selected mixed gas ratio B, while maintaining the selected deposition temperature T0 and deposition pressure P0. This allows the silicon-carbon source gas to react and deposit on the surface of the graphite substrate to form a SiC layered structure, thereby obtaining a SiC layered structure corresponding to the target resistivity range. This solution achieves directional preparation of the resistivity range of the SiC layered structure by correspondingly selecting the target resistivity range and the deposition parameter set, which is beneficial for improving production efficiency and product performance. 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 diagram of the main process of the resistivity-tunable SiC layer structure growth method in this embodiment. Figure 2 This is a schematic diagram of the first processing step in the resistivity-tunable SiC layer structure growth method of Example 1. Figure 3 This is a schematic diagram of the second processing step in the resistivity-tunable SiC layer structure growth method of Example 1. Figure 4 This is a schematic diagram of step three in the process of growing a SiC layered structure with adjustable resistivity according to Example 1. Figure 5 This is a schematic diagram of the substrate removal structure in the resistivity-tunable SiC layer structure growth method of Example 1. 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: Example 1: Combination Figures 1 to 5 The above, Figure 1 Main process diagram. Figure 2 This is a schematic diagram of the first processing step in the resistivity-tunable SiC layer structure growth method of Example 1. The diagram mainly shows that after the graphite substrate 10 is placed in the deposition chamber, it undergoes high-temperature purification pretreatment under vacuum and heating conditions, so that the graphite substrate 10 enters a pretreatment state suitable for subsequent deposition.

[0024] Figure 3 This is a schematic diagram of step two in the resistivity-tunable SiC layer structure growth method of Example 1. The diagram mainly shows the process of purging the deposition chamber with inert gas at the pre-deposition temperature and removing residual impurities from the deposition chamber, pipes, and the surface of the graphite substrate 10 by vacuum pumping.

[0025] Figure 4 This is a schematic diagram of step three in the resistivity-tunable SiC layer structure growth method of Example 1. The diagram mainly shows the introduction of MTS, hydrogen, and argon into the deposition chamber according to the mixed gas ratio, and the reaction deposition of SiC layer structure 20 on the surface of graphite substrate 10.

[0026] Figure 5 This is a partial structural schematic diagram of step four in the resistivity-tunable SiC layer structure growth method of Example 1. The diagram mainly shows the layered state of the SiC layer structure 20 attached to the surface of the graphite substrate 10 after deposition, illustrating the formation position and structural morphology of the SiC layer structure 20 relative to the graphite substrate 10.

[0027] This invention provides a method for growing a SiC layer structure 20 with adjustable resistivity, comprising: S1. Based on the target resistivity range of the SiC layer structure 20 to be prepared, a set of deposition parameters is selected. The set of deposition parameters includes deposition temperature T0, deposition pressure P0, and mixed gas ratio B. The mixed gas ratio B is the flow ratio of silicon-carbon source gas, hydrogen, and inert gas.

[0028] It should be noted that the target resistivity range can be determined based on the intended use case of the SiC layer structure 20. For example, the required resistivity range will differ depending on the component being used for insulation protection, wafer bonding, electrostatic discharge, or conductive support. Based on this target resistivity range, a corresponding set of deposition parameters is selected to ensure that the subsequent CVD deposition process is carried out under predetermined process conditions.

[0029] The deposition parameter set includes at least the deposition temperature T0, deposition pressure P0, and mixed gas ratio B. The deposition temperature T0 affects the decomposition state of the silicon-carbon source gas and the degree of deposition reaction on the substrate 10 surface. The deposition pressure P0 affects the transport, diffusion, and residence states of the reactive gas within the deposition chamber. The mixed gas ratio B is used to define the supply relationship between the silicon-carbon source gas, hydrogen, and inert gas. By selecting T0, P0, and B as a whole parameter set, the growth state of the SiC layer structure 20 can be correlated with the target resistivity range, thereby improving the directionality and repeatability of the fabrication process.

[0030] S2, graphite substrate 10 is placed in deposition chamber 100 for high-temperature purification pretreatment, and then deposition chamber 100 is controlled to pre-deposition temperature T1.

[0031] The graphite substrate 10 can adapt to the high-temperature reaction environment required for SiC deposition and has good thermal compatibility with the SiC material, which helps reduce the risk of cracking, warping, or peeling caused by thermal stress differences during subsequent deposition and cooling processes. High-temperature purification pretreatment is used to remove adsorbed gases, volatile impurities, and organic residues from the surface and near-surface of the graphite substrate 10, ensuring high cleanliness and thermal stability of the substrate 10 before entering the reaction deposition stage.

[0032] After high-temperature purification, the deposition chamber 100 is controlled to the pre-deposition temperature T1, so that the deposition chamber 100, the graphite substrate 10 and the internal atmosphere gradually enter the state to be deposited, so as to avoid the initial growth quality of SiC layer structure 20 being affected by temperature fluctuations of substrate 10 or unstable thermal state of the cavity when the mixed gas is formally introduced.

[0033] S3, according to the mixed gas ratio B, silicon-carbon source gas, hydrogen and inert gas are introduced into the deposition chamber 100 to maintain the deposition temperature T0 and deposition pressure P0, and SiC layer structure 20 is deposited on the surface of substrate 10.

[0034] According to the selected gas mixture ratio B, silicon-carbon source gas, hydrogen, and inert gas are introduced into the deposition chamber 100. The silicon-carbon source gas provides the silicon and carbon sources required for SiC formation, hydrogen carries the silicon-carbon source gas into the deposition chamber 100 and participates in regulating the reaction atmosphere, and the inert gas dilutes the reaction atmosphere and improves the stability of the deposition process. During the deposition process, the deposition temperature T0 and deposition pressure P0 are maintained, allowing the silicon-carbon source gas to decompose under high-temperature conditions and undergo surface reaction deposition on the graphite substrate 10, gradually forming the SiC layer structure 20.

[0035] Instead of altering resistivity through frequent parameter adjustments during deposition, the reaction atmosphere, reaction kinetics, and deposition growth state are jointly defined by pre-selected T0, P0, and B, ensuring that the resulting SiC hierarchical structure 20 corresponds to the target resistivity range. The deposition time can be determined based on the desired thickness of the SiC hierarchical structure 20; for example, deposition can continue until a structural thickness that meets the requirements for subsequent processing or use is achieved.

[0036] S4, stop the supply of silicon-carbon source gas, hydrogen and inert gas to the deposition chamber 100, and perform vacuum treatment on the deposition chamber 100.

[0037] Once the SiC layer structure 20 has reached the predetermined deposition state, the supply of silicon-carbon source gas, hydrogen, and inert gas to the deposition chamber 100 is stopped, and the deposition chamber 100 is evacuated. Since unreacted source gas, carrier gas, inert gas, and reaction byproducts may exist during the CVD reaction, if they remain in the deposition chamber 100 during the cooling phase, it may lead to unintended residual reactions or surface adhesion, thereby affecting the cleanliness and electrical stability of the SiC layer structure 20 surface.

[0038] S5, the deposition chamber 100 is naturally cooled to room temperature to obtain a graphite substrate 10 with the SiC layer structure 20 attached. Natural cooling allows the graphite substrate 10 and the SiC layer structure 20 to release thermal stress simultaneously as the temperature gradually decreases, reducing interfacial stress concentration caused by rapid cooling, thereby reducing the possibility of cracks, warping, or localized delamination of the SiC layer structure 20. Since the SiC layer structure 20 is still attached to the surface of the graphite substrate 10 at this stage, the graphite substrate 10 can continue to provide load-bearing and support for the SiC layer structure 20 during the cooling process, which is beneficial to maintaining the overall morphology and hierarchical state of the SiC layer structure 20.

[0039] S6, remove the graphite substrate 10 and perform a resistivity test on the SiC layer structure 20 to verify whether the resistivity of the SiC layer structure 20 is within the target resistivity range.

[0040] The graphite substrate 10 can be removed by mechanical grinding or other methods to reduce the impact of chemical treatment on the electrical properties and surface condition of the SiC layer structure 20. After obtaining the SiC layer structure 20, its resistivity is tested to verify whether the resistivity of the obtained SiC layer structure 20 is within the target resistivity range determined in S1. This resistivity test is a performance verification process after preparation and does not participate in the real-time control of the deposition process; through this verification result, it can be confirmed whether the correspondence between the selected deposition parameter set and the target resistivity range meets the product preparation requirements.

[0041] The working principle of this invention is as follows: During the growth process, firstly, based on the target resistivity range required to be achieved by the SiC layer structure 20 to be prepared, a set of deposition parameters corresponding to the target resistivity range is selected. The set of deposition parameters includes at least the deposition temperature T0, the deposition pressure P0, and the mixed gas ratio B, which is composed of the flow ratio of silicon-carbon source gas, hydrogen, and inert gas. Subsequently, graphite is placed in the deposition chamber 100 as a substrate for high-temperature purification pretreatment. After pretreatment, the deposition chamber 100 is controlled to the pre-deposition temperature T1, so that the graphite substrate 10 and the deposition chamber 100 are in a suitable environment for reaction. The deposition process is carried out under thermally stable conditions. Then, according to the selected mixed gas ratio B, silicon-carbon source gas, hydrogen, and inert gas are introduced into the deposition chamber 100, while maintaining the selected deposition temperature T0 and deposition pressure P0. This allows the silicon-carbon source gas to react and deposit on the surface of the graphite substrate 10 to form a SiC layer structure 20, thereby obtaining a SiC layer structure 20 corresponding to the target resistivity range. This scheme achieves directional preparation of the resistivity range of the SiC layer structure 20 by correspondingly selecting the target resistivity range with the CVD deposition parameter set, which is beneficial for improving production efficiency and product performance.

[0042] In this embodiment, the pretreatment of placing graphite substrate 10 into deposition chamber 100 for high-temperature purification includes: S21, the graphite substrate 10 is heated to 1800℃~2000℃ under an inert atmosphere and held at that temperature for 4~6 hours to allow impurities on the surface of the graphite substrate 10 to volatilize. Heating the graphite substrate 10 to 1800℃~2000℃ under an inert atmosphere and holding it at that temperature for 4~6 hours allows for the full volatilization of moisture, oxidizing impurities, volatile organic residues, and some low-boiling-point impurities adsorbed on the surface of the graphite substrate 10, thereby improving the cleanliness of the graphite substrate 10 surface. The inert atmosphere is used to isolate the graphite substrate 10 from external air, preventing oxidation or the introduction of new impurities at high temperatures. Through this high-temperature purification treatment, the graphite substrate 10 achieves a relatively stable chemical and surface state before entering the subsequent deposition stage.

[0043] S22, after heating is stopped, inert gas is continuously introduced into the environment containing the graphite substrate 10, and the cooling rate is controlled to ≤50℃ / min to cool the graphite substrate 10. Continuing to introduce inert gas into the environment containing the graphite substrate 10 after heating is stopped, while controlling the cooling rate to ≤50℃ / min, allows the graphite substrate 10 to gradually cool under a protective atmosphere, preventing the high-temperature graphite substrate 10 from directly contacting air and oxidizing. Controlling the cooling rate helps reduce the temperature gradient between the inside and surface of the graphite substrate 10, reducing thermal stress concentration, microcracks, or warping deformation caused by excessively rapid cooling. Therefore, the graphite substrate 10 can maintain good structural integrity and surface smoothness after high-temperature purification.

[0044] S23, the cooled graphite substrate 10 is fixed in the central region of the deposition chamber 100, and a preset distance is maintained between the surface of the graphite substrate 10 and the gas distributor of the deposition chamber 100.

[0045] Furthermore, maintaining a preset distance between the surface of the graphite substrate 10 and the gas distributor in the deposition chamber 100 ensures that the silicon-carbon source gas, hydrogen, and inert gas have sufficient diffusion and mixing space after entering the deposition area, allowing the reactive gases to reach the surface of the graphite substrate 10 more uniformly. This fixing method and spacing control improve the uniformity and repeatability of SiC layer structure 20 deposition on the surface of the graphite substrate 10.

[0046] S24, start the vacuum pump to evacuate the deposition chamber 100 in stages. In the first stage, the pressure in the deposition chamber 100 is reduced to below 10 kPa and maintained for 5 to 10 minutes. In the second stage, the vacuum is continued to be evacuated to the preset low pressure range.

[0047] The first stage involves reducing the pressure in the deposition chamber to below 10 kPa and maintaining this pressure for 5-10 minutes. This initially removes most of the air, water vapor, and residual gases from the chamber, achieving preliminary purification of the internal environment. The second stage then continues vacuuming to a preset low-pressure range, further reducing the residual gas content and minimizing interference from impurities such as oxygen and water vapor on the subsequent high-temperature deposition reaction. This staged vacuuming method, compared to a single, rapid vacuuming, results in more stable pressure changes within the deposition chamber.

[0048] In this embodiment, controlling the deposition chamber to the pre-deposition temperature T1 includes: In step S25, the graphite substrate 10 in the deposition chamber is heated to the pre-deposition temperature T1 at a stepped heating rate. Heating the graphite substrate 10 to the pre-deposition temperature T1 at a stepped heating rate allows the graphite substrate 10 and the deposition chamber to gradually enter a high-temperature pre-deposition state. The stepped heating is not a direct, rapid increase in temperature, but rather a gradual release of internal residual stress in the graphite substrate 10 at different temperature stages, and a tendency for temperature equilibrium between the inner wall of the deposition chamber, the support structure, and the graphite substrate 10. This method reduces the risk of thermal shock, localized overheating, or temperature fluctuations in the graphite substrate 10 during the heating process, resulting in a more stable thermal environment for subsequent inert gas purging and formal deposition processes.

[0049] S26. At the pre-deposition temperature T1, inert gas is introduced into the deposition chamber, and a pulsed injection method is used to purge for 20-40 minutes to remove residual volatile impurities in the deposition chamber, pipes, and the surface of the graphite substrate 10. Introducing inert gas into the deposition chamber at the pre-deposition temperature T1 and purging with a pulsed injection method for 20-40 minutes utilizes the intermittent airflow impact to remove residual volatile impurities from the deposition chamber, pipes, and the surface of the graphite substrate 10. Compared to continuous and stable aeration, pulsed injection enhances the scouring effect of the gas on the inner wall of the pipes and the surface of the substrate 10, making it easier for residual impurities to detach and be discharged with the airflow. Because this purging process is carried out at the pre-deposition temperature T1, residual impurities are more likely to volatilize or desorb, thus contributing to the formation of a clean and stable deposition environment before the formal introduction of the mixed gas.

[0050] S27. During the purging process, the vacuum pump is activated to simultaneously extract gas and maintain the pressure in the deposition chamber at 50-80 kPa. On one hand, inert gas continuously enters the deposition chamber, flushing the interior of the chamber, the pipes, and the surface of the graphite substrate 10; on the other hand, the vacuum pump simultaneously extracts gas to promptly remove the purged impurities from the deposition chamber, preventing impurities from being re-adsorbed or retained within the chamber. Maintaining the pressure during the purging stage at 50-80 kPa helps maintain sufficient gas displacement capacity while avoiding a decrease in purging efficiency due to excessively high or low pressure.

[0051] In this embodiment, heating the graphite substrate 10 in the deposition chamber to the pre-deposition temperature T1 at a stepped heating rate includes: In the first stage, the graphite substrate 10 is heated to 800°C at a heating rate of 10°C / min and held at a constant temperature for 10 minutes to release the internal stress of the graphite substrate 10. In the second stage, the graphite substrate 10 is heated to the pre-deposition temperature T1 at a heating rate of 5℃ / min, and the surface temperature fluctuation of the graphite substrate 10 is controlled to not exceed ±5℃ during the heating process.

[0052] In the first stage, the graphite substrate 10 is heated to 800℃ at a heating rate of 10℃ / min and held at that temperature for 10 minutes. This stage is mainly used to allow the graphite substrate 10 to smoothly transition from room temperature to a medium-high temperature state. Since the graphite substrate 10 may have some residual thermal stress or surface adsorption residues from the preceding high-temperature purification, cooling, and furnace loading processes, directly and rapidly heating it to the pre-deposition temperature T1 could easily cause an excessively large internal temperature gradient, leading to localized thermal stress concentration. By holding the substrate at 800℃ for a short period, the internal temperature of the graphite substrate 10 can be gradually equalized, and some residual stress can be released, thereby improving the structural stability of the graphite substrate 10 in the subsequent high-temperature deposition environment.

[0053] In the second stage, the graphite substrate 10 is further heated to the pre-deposition temperature T1 at a heating rate of 5℃ / min, while controlling the surface temperature fluctuation of the graphite substrate 10 to not exceed ±5℃ during the heating process. Compared with the first stage, the second stage is closer to the high-temperature range before formal deposition. Therefore, using a lower heating rate helps to avoid a large temperature difference between the surface and interior of the graphite substrate 10, making the temperature field in the deposition chamber more uniform. Controlling the surface temperature fluctuation within ±5℃ can reduce the differences in reaction decomposition rate, uneven initial nucleation, or local thickness differences in the deposited layer caused by local temperature deviations when the mixed gas is formally introduced, thereby improving the consistency of SiC layer structure 20 growth.

[0054] In this embodiment, it is further explained that the silicon-carbon source gas is methyltrichlorosilane and the inert gas is argon; in the deposition parameter group, the deposition temperature T0 is 1360℃~1460℃, the deposition pressure P0 is 10kPa~18kPa, and the mixed gas ratio B includes methyltrichlorosilane flow rate of 10~43g / min, hydrogen flow rate of 42~50L / min, and argon flow rate of 45L / min.

[0055] It should be noted that methyltrichlorosilane is used as the silicon-carbon source gas, and argon is used as the inert gas. Methyltrichlorosilane contains both silicon and carbon elements, and it can decompose at a deposition temperature T0 of 1360℃~1460℃ to form a SiC hierarchical structure 20 on the surface of the graphite substrate 10. Hydrogen is used to carry methyltrichlorosilane into the deposition chamber and plays an auxiliary role in the removal of the reaction atmosphere and byproducts. Argon participates in atmosphere dilution at a flow rate of 45L / min, which helps to improve the stability of the reaction gas distribution. By controlling the flow rate of methyltrichlorosilane to 10~43g / min, the flow rate of hydrogen to 42~50L / min, and the deposition pressure P0 to 10kPa~18kPa, different deposition parameter sets can correspond to different SiC growth states, thereby obtaining SiC hierarchical structures 20 with different target resistivity ranges.

[0056] In this embodiment, based on the target resistivity range of the SiC layer structure 20 to be prepared, a set of deposition parameters is selected, including: S11 provides multiple preset deposition parameter groups, each of which includes the corresponding deposition temperature T0, deposition pressure P0, and mixed gas ratio B; Multiple preset deposition parameter groups can be pre-set according to different target resistivity ranges. Each preset deposition parameter group manages the deposition temperature T0, deposition pressure P0, and mixed gas ratio B as a whole process window, rather than using a single parameter as the basis for resistivity control. Among them, the deposition temperature T0 mainly affects the decomposition degree of silicon-carbon source gas and the nucleation and growth state of SiC on the substrate 10 surface; the deposition pressure P0 mainly affects the diffusion, residence, and exhaust state of the reactive gas in the deposition chamber; and the mixed gas ratio B is used to limit the supply relationship between the silicon-carbon source gas, hydrogen, and inert gas.

[0057] S12, SiC layered structures 20 are prepared using each preset deposition parameter group, and the resistivity of the prepared SiC layered structures 20 is tested to obtain the resistivity range corresponding to each preset deposition parameter group. SiC layered structures 20 were prepared using various preset deposition parameter sets, and the resistivity of the resulting SiC layered structures 20 was measured after preparation to obtain the resistivity range corresponding to each preset deposition parameter set. Specifically, SiC layered structures 20 prepared with different preset deposition parameter sets can be tested under the same substrate type 10, the same deposition equipment, and the same test conditions to reduce the influence of differences in substrate 10, equipment, or test conditions on the determination of resistivity range. Resistivity testing can serve as a confirmation method for the preparation results, establishing the correspondence between the preset deposition parameter sets and the resistivity ranges of the SiC layered structures 20.

[0058] S13, match the target resistivity range with the resistivity range corresponding to each preset deposition parameter group, and select the matched preset deposition parameter group as the deposition parameter group.

[0059] The target resistivity range of the SiC layered structure 20 to be prepared is matched with the resistivity ranges corresponding to each preset deposition parameter group, and the matched preset deposition parameter group is used as the deposition parameter group for the formal deposition. The matching can be understood as the target resistivity range being the same as, intersecting with, or meeting a predetermined deviation requirement of the resistivity range corresponding to a certain preset deposition parameter group. When multiple preset deposition parameter groups can meet the target resistivity range, the preset deposition parameter group with higher deposition stability, better repeatability, or larger process margin can be preferentially selected. Through this matching process, the deposition temperature T0, deposition pressure P0, and mixed gas ratio B can be determined before formal preparation, ensuring that the subsequent deposition process is stably executed according to the selected process window, thereby improving the reliability of obtaining the target resistivity range for the SiC layered structure 20.

[0060] In this embodiment, the pre-deposition temperature T1 is a pre-stabilization temperature determined based on the deposition temperature T0, and the pre-deposition temperature T1 is equal to the deposition temperature T0, or the temperature difference between the pre-deposition temperature T1 and the deposition temperature T0 is no greater than 10°C.

[0061] Before introducing the silicon-carbon source gas, hydrogen, and inert gas corresponding to the mixed gas ratio B, the deposition chamber is first purged with inert gas at the pre-deposition temperature T1, and the deposition chamber is stabilized at the deposition temperature T0 after the purging is completed.

[0062] The pre-deposition temperature T1 is a pre-stabilization temperature determined based on the deposition temperature T0. The pre-deposition temperature T1 can be equal to the deposition temperature T0, or it can maintain a temperature difference of no more than 10°C from T0. By making T1 close to or equal to T0, the graphite substrate 10 and the deposition chamber are already in a thermally stable state close to the formal deposition state before the formal introduction of methyltrichlorosilane, hydrogen, and argon. In this state, inert gas purging can more effectively remove volatile residues from the deposition chamber, pipes, and the surface of the graphite substrate 10. After purging, stabilizing the deposition chamber at the deposition temperature T0 can reduce the temperature jump at the start of formal deposition, making the initial deposition process of the SiC layer structure 20 more stable.

[0063] Example 2: Unlike Example 1, the graphite substrate was heated to 1365°C, the flow rate of methyltrichlorosilane in the mixed gas was 35 g / min, the flow rate of hydrogen was 47 L / min, and the pressure in the deposition chamber was maintained at 18 kPa; the resistivity of the obtained silicon carbide layer structure was 200~2000 Ω·cm.

[0064] Example 3: Unlike Example 1, the graphite substrate is heated to 1380℃, the flow rate of methyltrichlorosilane in the mixed gas is 20g / min, the flow rate of hydrogen is 50L / min, and the pressure in the deposition chamber is maintained at 12kPa; the resistivity of the obtained silicon carbide layer structure is 150000~330000Ω·cm.

[0065] Example 4: Unlike Example 1, the graphite substrate is heated to 1400℃, the flow rate of methyltrichlorosilane in the mixed gas is 20g / min, the flow rate of hydrogen is 50L / min, and the pressure in the deposition chamber is maintained at 12kPa; the resistivity of the obtained silicon carbide layer structure is 83000~130000Ω·cm.

[0066] Example 5: Unlike Example 1, the graphite substrate is heated to 1410°C, the flow rate of methyltrichlorosilane in the mixed gas is 20 g / min, the flow rate of hydrogen is 50 L / min, and the pressure in the deposition chamber is maintained at 10 kPa; the resistivity of the obtained silicon carbide layer structure is 520000~890000 Ω·cm.

[0067] Example 6: Unlike Example 1, the graphite substrate is heated to 1425°C, the flow rate of methyltrichlorosilane in the mixed gas is 10 g / min, the flow rate of hydrogen is 49 L / min, and the pressure in the deposition chamber is maintained at 18 kPa; the resistivity of the obtained silicon carbide layer structure is 2~60 Ω·cm.

[0068] Example 7: Unlike Example 1, the graphite substrate is heated to 1460°C, the flow rate of methyltrichlorosilane in the mixed gas is 20 g / min, the flow rate of hydrogen is 50 L / min, and the pressure in the deposition chamber is maintained at 18 kPa; the resistivity of the obtained silicon carbide layer structure is 32000~61000 Ω·cm.

[0069] Table 1: Resistivity of SiC materials prepared under various process conditions Example 8: The present invention also provides a resistivity-tunable SiC layer structure, which is prepared by the resistivity-tunable SiC layer structure growth method of any one of the embodiments of claims 1 to 7; the resistivity of the SiC layer structure is in the target resistivity range corresponding to the deposition parameter set.

[0070] Example 9: The present invention also provides a semiconductor device, including the resistivity-tunable SiC layer structure of the embodiment.

[0071] The above 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 growing SiC layered structures with adjustable resistivity, characterized in that, include: Based on the target resistivity range of the SiC layer structure to be prepared, a set of deposition parameters is selected, including deposition temperature T0, deposition pressure P0, and mixed gas ratio B; the mixed gas ratio B is the flow ratio of silicon-carbon source gas, hydrogen, and inert gas. Graphite as a substrate is placed in a deposition chamber for high-temperature purification pretreatment, and then the deposition chamber is controlled to the pre-deposition temperature T1; According to the mixed gas ratio B, silicon-carbon source gas, hydrogen and inert gas are introduced into the deposition chamber to maintain the deposition temperature T0 and the deposition pressure P0, and SiC layer structure is deposited on the substrate surface.

2. The method for growing SiC layered structures with adjustable resistivity according to claim 1, characterized in that, After depositing the SiC layer structure on the substrate surface, the method further includes: Stop supplying silicon-carbon source gas, hydrogen, and inert gas to the deposition chamber, and evacuate the deposition chamber. The deposition chamber is naturally cooled to room temperature to obtain a graphite substrate with the SiC layer structure attached. The graphite substrate is removed, and the resistivity of the SiC layer structure is tested to verify whether the resistivity of the SiC layer structure is within the target resistivity range.

3. The method for growing SiC layered structures with adjustable resistivity according to claim 1, characterized in that, The pretreatment, in which graphite is placed in a deposition chamber for high-temperature purification, includes: The graphite substrate is heated to 1800℃~2000℃ under an inert atmosphere and kept at a constant temperature for 4~6 hours to allow impurities on the surface of the graphite substrate to volatilize. After heating is stopped, inert gas is continuously introduced into the environment where the graphite substrate is located, and the cooling rate is controlled to be ≤50℃ / min to cool the graphite substrate. The cooled graphite substrate is fixed in the central region of the deposition chamber, and a preset distance is maintained between the surface of the graphite substrate and the gas distributor of the deposition chamber. The vacuum pump is started to evacuate the deposition chamber in stages. In the first stage, the pressure in the deposition chamber is reduced to below 10 kPa and maintained for 5 to 10 minutes. In the second stage, the vacuum is continued to be evacuated to the preset low pressure range.

4. The method for growing SiC layered structures with adjustable resistivity according to claim 1, characterized in that, The control of the deposition chamber to the pre-deposition temperature T1 includes: The graphite substrate in the deposition chamber is heated to the pre-deposition temperature T1 at a stepped heating rate. At the pre-deposition temperature T1, inert gas is introduced into the deposition chamber and purged for 20 to 40 minutes using a pulse injection method to remove volatile impurities remaining in the deposition chamber, pipes, and the surface of the graphite substrate. During the purging process, the vacuum pump is started to pump air synchronously and the pressure in the deposition chamber is maintained at 50~80kPa.

5. The method for growing SiC layered structures with adjustable resistivity according to claim 4, characterized in that, The step of heating the graphite substrate in the deposition chamber to the pre-deposition temperature T1 at a stepped heating rate includes: In the first stage, the graphite substrate is heated to 800°C at a heating rate of 10°C / min and held at that temperature for 10 minutes to release the internal stress of the graphite substrate. In the second stage, the graphite substrate is heated to the pre-deposition temperature T1 at a heating rate of 5℃ / min, and the surface temperature fluctuation of the graphite substrate is controlled to not exceed ±5℃ during the heating process.

6. The method for growing SiC layered structures with adjustable resistivity according to claim 1, characterized in that, The silicon-containing carbon source gas is methyltrichlorosilane, and the inert gas is argon. In the deposition parameter set, the deposition temperature T0 is 1360℃~1460℃, the deposition pressure P0 is 10kPa~18kPa, and the mixed gas ratio B includes methyltrichlorosilane flow rate of 10~43g / min, hydrogen flow rate of 42~50L / min, and argon flow rate of 45L / min.

7. The method for growing SiC layered structures with adjustable resistivity according to claim 1, characterized in that, The step of selecting a set of deposition parameters based on the target resistivity range of the SiC layer structure to be prepared includes: Multiple preset deposition parameter groups are provided, each of which includes a corresponding deposition temperature T0, deposition pressure P0, and mixed gas ratio B; SiC layered structures were prepared using each of the preset deposition parameter sets, and the resistivity of the prepared SiC layered structures was tested to obtain the resistivity range corresponding to each of the preset deposition parameter sets. The target resistivity range is matched with the resistivity range corresponding to each preset deposition parameter group, and the matched preset deposition parameter group is selected as the deposition parameter group.

8. The method for growing SiC layered structures with adjustable resistivity according to claim 7, characterized in that, The pre-deposition temperature T1 is a pre-stabilization temperature determined based on the deposition temperature T0, and the pre-deposition temperature T1 is equal to the deposition temperature T0, or the temperature difference between the pre-deposition temperature T1 and the deposition temperature T0 is not greater than 10℃. Before introducing the silicon-carbon source gas, hydrogen, and inert gas corresponding to the mixed gas ratio B, the deposition chamber is first purged with inert gas at the pre-deposition temperature T1, and after purging, the deposition chamber is stabilized at the deposition temperature T0.

9. A SiC layer structure with adjustable resistivity, characterized in that, It is prepared by the resistivity-tunable SiC layer structure growth method as described in any one of claims 1 to 8; The resistivity of the SiC layer structure is within the target resistivity range corresponding to the deposition parameter set.

10. A semiconductor device, characterized in that, This includes the resistivity-tunable SiC layer structure as described in claim 9.

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