Method for producing silicon carbide substrate

Abstract

The invention relates to a method for manufacturing a substrate (300) comprising a polycrystalline silicon carbide layer (30, 30A, 30B) and a single crystal silicon carbide layer (20, 20A, 30B) in direct contact with the polycrystalline silicon carbide layer, the method comprising the following steps in sequence:-transferring a first single crystal silicon carbide layer (20, 20A) to a front face of a temporary graphite support substrate (10),-transferring the first single crystal silicon carbide layer (20, 20A) to the front face of the temporary graphite support substrate (10),-transferring the first single crystal silicon carbide layer (20, 20A) to the back face of the temporary graphite support substrate (10), and-transferring the first single crystal silicon carbide layer (20, 20A) to the back face of the temporary graphite support substrate (10). Depositing polycrystalline silicon carbide on the temporary graphite support substrate (10) to form the polycrystalline silicon carbide layer (30, 30A),-removing the temporary graphite support substrate (10).

Description

Technical Field

[0001] This invention generally relates to the field of silicon carbide substrates for forming electronic components. More specifically, this invention provides a method for manufacturing a substrate comprising a polycrystalline silicon carbide layer and a monocrystalline silicon carbide layer. Background Technology

[0002] Single-crystal silicon carbide (sc-SiC) is used to form electronic components, such as for applications in radio frequency or power electronics.

[0003] Fabrication of sc-SiC is complex and expensive. Therefore, instead of using bulk sc-SiC substrates, polycrystalline silicon carbide (p-SiC) substrates with sc-SiC layers formed on their surfaces are typically used, where electronic components are formed. These substrates are usually smart-cut. TM The manufacturing process involves transferring the sc-SiC layer from the donor substrate to the p-SiC support substrate.

[0004] To ensure good mechanical and electrical contact between the support substrate and the sc-SiC layer, the support substrate must have uniform crystal quality and a very smooth surface. Therefore, this Smart Cut... TM The process requires careful fabrication of the p-SiC support substrate. This fabrication involves depositing a thick p-SiC layer onto a temporary substrate, followed by the removal of the temporary substrate. Significant thickness is then removed from the p-SiC layer to retain only a thin portion with crystal quality suitable for depositing the sc-SiC layer. Therefore, the thick p-SiC layer typically has an initial thickness of 900 μm to 3000 μm. After removing the portion with poorer crystal quality, a thickness typically around 350 μm is retained, which has crystal quality suitable for receiving the sc-SiC layer. Thus, this process involves a significant consumption of p-SiC, which is removed before the sc-SiC layer is deposited and therefore not used in the substrate to be fabricated.

[0005] Smart Cut TM The preparation process also involves laborious steps in fabricating the p-SiC surface to obtain a very smooth surface. This preparation is necessary for the deposition of the sc-SiC layer in order to achieve good mechanical and electrical contact at the interface between the p-SiC supporting substrate and the sc-SiC layer. These preparation steps typically include treatments such as mechanical and chemical polishing. However, these treatments are difficult to perform on silicon carbide and require considerable time due to its high hardness. The grain boundaries present in polycrystalline materials further complicate surface smoothing. Moreover, mechanical processing involves the risk of fracture, rendering the substrate unusable. Summary of the Invention

[0006] One object of the present invention is to design a method for manufacturing a substrate comprising a polycrystalline silicon carbide layer and a single-crystal silicon carbide layer, wherein the above-described steps for preparing a polycrystalline silicon carbide support substrate can be omitted.

[0007] Therefore, the present invention proposes a method for manufacturing a substrate, the substrate comprising a polycrystalline silicon carbide layer and a single-crystal silicon carbide layer in direct contact with the polycrystalline silicon carbide layer, the method comprising the following sequential steps:

[0008] • The first single-crystal silicon carbide layer is transferred to the front side of the graphite temporary support substrate.

[0009] • Polycrystalline silicon carbide is deposited onto the first single-crystal silicon carbide layer to form the polycrystalline silicon carbide layer.

[0010] • Remove the graphite temporary support substrate (10).

[0011] This graphite temporary support substrate has a thermal expansion coefficient close to that of single-crystal silicon carbide, making it particularly suitable. Therefore, the mechanical stress occurring during cooling after the deposition step is minimized. Consequently, using this temporary support substrate prevents substrate fracture during this step.

[0012] In this document, the term "continuously" means that the steps are performed in the order they are indicated, without excluding the implementation of one or more intermediate steps. Such intermediate steps may, for example, involve preparing the surface of a transferred single-crystal SiC layer prior to the deposition of a polycrystalline SiC layer.

[0013] Advantageously, the method further includes transferring a second monocrystalline silicon carbide layer onto the back side of a temporary support substrate prior to depositing polycrystalline silicon carbide, wherein depositing polycrystalline silicon carbide includes forming a second polycrystalline silicon carbide layer on the second monocrystalline silicon carbide layer.

[0014] Using temporary support substrates on its two free surfaces allows for increased process yield.

[0015] The process may include applying an adhesive layer between each single-crystal silicon carbide layer and a temporary support substrate.

[0016] Preferably, transferring each single-crystal silicon carbide layer onto a temporary support substrate includes the following steps:

[0017] • By implanting atomic material into a single-crystal silicon carbide donor substrate, an embrittlement region is formed.

[0018] • The donor substrate is bonded to the free surface of the temporary support substrate.

[0019] • Peel off the donor substrate along the embrittlement region in order to transfer the single-crystal silicon carbide layer onto a temporary support substrate.

[0020] Advantageously, each polycrystalline silicon carbide layer is deposited via chemical vapor deposition. Chemical vapor deposition ensures very good electrical and mechanical contact between the p-SiC and sc-SiC layers.

[0021] Advantageously, the method further includes heat treatment at a temperature higher than the deposition temperature after depositing the polycrystalline silicon carbide layer. Preferably, the heat treatment is performed at a temperature greater than or equal to 1700°C.

[0022] The step of removing the temporary support substrate may include burning graphite at a temperature of 800°C to 900°C under an oxygen flow. In some embodiments, the step of removing the temporary support substrate includes chemical etching or oxygen plasma etching. The step of removing the temporary support substrate may include a polishing step.

[0023] Advantageously, the thickness of the temporary support substrate is 1 to 15 mm. The thickness of the first single-crystal silicon carbide layer can be 400 nm to 5 μm, preferably 400 nm to 2 μm, and more preferably 400 nm to 1 μm. Advantageously, the thickness of the first polycrystalline silicon carbide layer is 100 μm to 2 mm.

[0024] In some embodiments, the front side of the graphite temporary support has a first dimension, and the first single-crystal silicon carbide layer has a second dimension less than or equal to half of the first dimension, such that the first layer forms a first block. The method further includes transferring at least a second single-crystal silicon carbide block onto the front side of the temporary support substrate, such that the first block and the second block are arranged side by side on the front side of the temporary support substrate. The step of depositing a polycrystalline silicon carbide layer includes forming a corresponding polycrystalline silicon carbide layer on each block.

[0025] The present invention also relates to an intermediate substrate comprising:

[0026] · Graphite temporary support substrate,

[0027] • A first single-crystal silicon carbide layer disposed on the front side of the temporary support substrate, and

[0028] • A first polycrystalline silicon carbide layer, which is arranged to be in direct contact with the first monocrystalline silicon carbide layer.

[0029] Advantageously, the thickness of the monocrystalline silicon carbide layer is 400 nm to 5 μm, preferably 400 nm to 2 μm, and more preferably 400 nm to 1 μm, and the thickness of the polycrystalline silicon carbide layer is 100 μm to 2 mm.

[0030] Preferably, the front side of the graphite temporary support substrate has a first size, and the first single-crystal silicon carbide layer has a second size less than or equal to half of the first size, such that the first layer forms a first block, and the intermediate substrate further includes at least a second single-crystal silicon carbide block, such that the first block and the second block are arranged side by side on the front side of the temporary support substrate, and a polycrystalline silicon carbide layer is arranged on each single-crystal silicon carbide block. Attached Figure Description

[0031] Other features and advantages of the invention will become apparent from the following detailed description with reference to the accompanying drawings, in which:

[0032] Figure 1 The formation of embrittlement regions in sc-SiC donor substrates is shown.

[0033] Figure 2 The transfer of the sc-SiC layer onto a temporary support substrate is shown.

[0034] Figure 3 This is a schematic diagram of a temporary support substrate including the sc-SiC layer.

[0035] Figure 4 This is a schematic diagram of a temporary support substrate including sc-SiC and p-SiC layers.

[0036] Figure 5 A substrate comprising a polycrystalline silicon carbide layer and a monocrystalline silicon carbide layer is shown.

[0037] Figure 6 This is a schematic diagram of a temporary support substrate including two sc-SiC layers.

[0038] Figure 7 This is a schematic diagram of a temporary support substrate consisting of two sc-SiC layers and two p-SiC layers.

[0039] Figure 8 It shows from Figure 7 Two substrates were obtained from a temporary support substrate.

[0040] Figure 9 A temporary support substrate comprising several juxtaposed sc-SiC layers is shown. Detailed Implementation

[0041] In the method according to the invention, a temporary support substrate is used on which a first single-crystal silicon carbide layer (sc-SiC) is transferred. The temporary support substrate serves as a mechanical support for the sc-SiC layer. Due to its temporary nature, the interface between the temporary support substrate and the sc-SiC layer requires only relatively simple basic preparation. This preparation does not involve any complex or critical steps regarding cleaning, uniformity, or adhesion between the layer and the substrate.

[0042] A polycrystalline silicon carbide (p-SiC) layer is then deposited onto the first sc-SiC layer, while the first layer is held on a temporary substrate. During deposition, the temporary support substrate ensures the mechanical stability of the sc-SiC layer. The temporary support substrate is then removed.

[0043] Figures 1 to 5 The steps of the method according to the present invention are shown. (Reference) Figure 1 As schematically shown by the arrow, ionic material is implanted into the sc-SiC donor substrate 200. The ionic material is, for example, hydrogen and / or helium. This creates an embrittlement region 21 that defines the sc-SiC layer 20 to be transferred.

[0044] refer to Figure 2 The donor substrate 200, thus injected, is bonded to the graphite temporary substrate 10. Bonding can be achieved by means of an adhesive layer applied to the donor substrate and / or temporary support substrate before the two substrates are placed in contact. The adhesive layer is, for example, a silicon layer, a tungsten layer, a polymer layer, or an oxide layer.

[0045] Typically, the graphite support substrate has the same surface area as the donor substrate 200, for example, a diameter of approximately 150 mm or 200 mm. This size facilitates handling the bonded substrates and allows the use of equipment suitable for fabricating semiconductor substrates. Alternatively, the surface area of ​​the temporary support substrate can be larger than that of the donor substrate 200. The larger surface area of ​​the temporary support substrate allows for the avoidance of edge effects, particularly deformation (warping) near the substrate edges during the bonding and deposition steps described below. The thickness of the temporary support substrate is typically 1 to 15 mm to ensure sufficient mechanical stability of the sc-SiC layer during the process.

[0046] refer to Figure 3 The donor substrate 200 is peeled along the embrittlement region 21, for example by heat treatment or by applying mechanical stress, which causes the sc-SiC layer 20 to transfer onto the graphite temporary substrate 10. The transferred layer 20 can then be finished, for example by polishing and / or heat treatment. This treatment is used to heal implantation-related defects and smooth the free surface of the sc-SiC layer 20 to optimize the surface quality for the following steps. In this invention, finishing is generally avoided because the p-SiC layer will be deposited on the surface created by the peeling. Therefore, there is no need to provide increased smoothness to the surface obtained during the peeling process, since no bonding is performed on that surface. Furthermore, any roughness will be compensated for during the deposition of the p-SiC layer.

[0047] refer to Figure 4Subsequently, a polycrystalline silicon carbide layer 30 is deposited onto the free surface of the sc-SiC layer 20 disposed on the temporary support substrate 10. Preferably, the p-SiC layer is deposited by a chemical vapor deposition (CVD) process. During CVD deposition, silicon and carbon atoms are introduced into the sc-SiC layer 20. Therefore, during deposition, direct chemical bonds are established between the atoms of the sc-SiC layer 20 and the atoms of the p-SiC layer 30, resulting in crystallographic continuity at the interface between the two layers. Thus, chemical vapor deposition allows for very good electrical and mechanical contact between the p-SiC layer and the sc-SiC layer.

[0048] Typically, adjusting the deposition parameters results in a fine, micron-scale microstructure in the p-SiC layer. This allows for improved crystallographic continuity at the interface between the two layers and thus limits mechanical deformation of the substrate being fabricated. As a non-limiting illustration, the p-SiC layer is deposited at temperatures ranging from 1100°C to 1500°C.

[0049] CVD deposition is performed on the main surface of the sc-SiC layer 20. However, a certain amount of p-SiC may be deposited onto the edge of the substrate and will be removed in a subsequent step. Similarly, a certain amount of SiC may be deposited onto the back side and removed along with the temporary support substrate.

[0050] Heat treatment can then be applied to activate the dopants in the sc-SiC layer 20 and the p-SiC layer 30. Heat treatment also promotes the relaxation of mechanical stress in the substrate comprising the sc-SiC layer 20 and the p-SiC layer 30. These effects improve crystal quality, thereby improving the electrical and thermal conductivity at the interface between the sc-SiC and p-SiC layers.

[0051] Such heat treatment is typically performed at a temperature of approximately 1700°C. Through bonding, the sc-SiC layer is held on the temporary support substrate 10 without the risk of peeling off during heat treatment.

[0052] During the deposition of p-SiC layers, such as in a CVD chamber, material is typically deposited onto the edges and / or back surface of a substrate. If the edges of the temporary support substrate have been covered during p-SiC layer deposition, substrate edge removal is performed to expose the edges of the sc-SiC layer and the temporary support substrate. Typically, p-SiC deposited on the substrate edges is removed by chemical etching, mechanical polishing or buffing, or thermal treatment.

[0053] Alternatively, a diamond tip is used to create a notch along the edge of the substrate to form a mechanically embrittled zone. Mechanical action is then applied to fracture the substrate along the embrittled zone, thereby removing the edge of the substrate.

[0054] refer to Figure 5Then, the temporary support substrate 10 is removed. By way of non-limiting illustration, the temporary support substrate 10 can be removed by combustion or chemical etching. For example, combustion can be performed at a temperature of 800°C to 900°C under an oxygen flow. Chemical etching can be performed, for example, by applying nitric acid or potassium hydroxide. Alternatively, the temporary support substrate can be removed by means of an oxygen plasma etching step. These steps also allow for the removal of the adhesive layer applied for transferring the sc-SiC layer.

[0055] In some cases, a polishing step is also applied to remove the temporary support substrate without leaving any residue on the sc-SiC layer.

[0056] In some implementations, such as Figures 6 to 8 As shown, two substrates, 300A and 300B, are fabricated using two sides of a temporary support substrate. Each substrate includes a sc-SiC thin layer and a p-SiC layer. (Reference) Figure 6 The first sc-SiC layer 20A is transferred to the front side of the graphite temporary support substrate 10, and the second sc-SiC layer 20B is transferred to the back side of the temporary support substrate 10. The two sc-SiC layers can be deposited sequentially, for example, from the same sc-SiC donor substrate or from two different sc-SiC substrates.

[0057] refer to Figure 7 The p-SiC layers 30A and 30B are deposited on each of the corresponding sc-SiC layers 20A and 20B. Preferably, two p-SiC layers are deposited simultaneously in the same chamber, such as a CVD chamber. This allows for improved process efficiency by performing the deposition of two layers instead of just one layer within a limited time and in the same space of the CVD chamber. For such simultaneous deposition on two sides of the same substrate, a certain amount of p-SiC is typically deposited onto the edge of the substrate and will be removed in a subsequent step.

[0058] The other steps in the process using both sides of the temporary support substrate are performed in the same manner as in the process using only one side of the temporary support substrate described above.

[0059] In this embodiment, material is also deposited onto the edges of the supporting substrate and the corresponding p-SiC layers. For this purpose, the edges of the substrate are removed to expose the edges of the two sc-SiC layers and the temporary supporting substrate. Typically, the p-SiC deposited on the substrate edges is removed by chemical etching, mechanical polishing or buffing, or thermal treatment.

[0060] Alternatively, a diamond tip is used to create indentations along the edge of the substrate to form a mechanically embrittled zone. Mechanical action is then applied to fracture the substrate along the embrittled zone, thereby removing the edge of the substrate.

[0061] This step provides access to the edge of the temporary support substrate for the step of removing the support substrate.

[0062] refer to Figure 8 After layers 30A and 30B are completed, their processing on the temporary support substrate 10 is performed, and the edges are removed, for example by combustion or chemical etching. Two substrates 300A and 300B are then obtained. This variation allows for increased process yield by using two opposing surfaces of the support substrate.

[0063] In some implementations, reference Figure 9 Multiple sc-SiC blocks 20C, 20D, and 20E are transferred side-by-side to a single surface of a temporary support substrate 10. In this case, the surface area of ​​the temporary support substrate is significantly larger than the surface area of ​​the transferred sc-SiC layers 20C, 20D, and 20E. These blocks do not overlap, and typically the regions between the edges of the individual blocks remain free on the temporary support substrate 10. The geometry of the blocks can be circular, rectangular, or other. Depending on the shape and size of the blocks and the temporary support substrate, regions near the edges of the temporary support substrate may also remain free.

[0064] Several corresponding sc-SiC blocks can also be transferred side-by-side on the front and back sides of such a large temporary support substrate. This implementation also allows for optimized process yield.

[0065] Then, a p-SiC layer is simultaneously deposited on the entire surface of a temporary support substrate comprising multiple sc-SiC blocks 20C, 20D, and 20E. The same steps and substrate treatment described above for a single p-SiC layer can be applied.

[0066] The deposited p-SiC layer is then diced away in a free region of the temporary support substrate that does not contain any sc-SiC layer. By way of non-limiting illustration, the p-SiC region deposited on the free region of the temporary support substrate is removed by laser cutting or cutting with a diamond tip. These methods are efficient at cutting p-SiC. SiC deposited on the edges of the graphite temporary support substrate is also removed to expose the edges of the support substrate for graphite removal. By way of non-limiting illustration, the SiC on the front side of the temporary support substrate is first diced, and then the SiC on the edges of the temporary support substrate is removed. After this step, the temporary support substrate is removed, for example, by burning or chemical etching.

[0067] Therefore, several corresponding substrates are obtained from several sc-SiC layers transferred at the beginning of the process.

[0068] Typically, final shaping is performed after producing one or more substrates comprising sc-SiC thin layers and p-SiC layers. Such steps may include, for example, mechanical trimming and / or polishing to remove deposits on the edges of each substrate and to homogenize the edges of each resulting substrate.

[0069] The thickness of each sc-SiC layer transferred to the temporary support substrate is 400 nm to 5 μm. Preferably, the thickness of the transferred sc-SiC layer is 400 nm to 2 μm, and more preferably 400 nm to 1 μm.

[0070] Layers of this thickness are too thin to be self-supporting. During the deposition of each p-SiC layer, the thin sc-SiC layer is held on a temporary support substrate by bonding performed during the transfer step. The temporary support substrate ensures the mechanical integrity and stability of the sc-SiC layer during p-SiC layer deposition. This allows for the deposition of uniform p-SiC layers with good crystal quality.

[0071] Using a thin sc-SiC layer allows for the production of multiple substrates from the same sc-SiC donor substrate. This optimizes the yield of such donor substrates, which are difficult and labor-intensive to fabricate. The limited thickness of the sc-SiC layer also allows for mitigation of the effects of small differences in the coefficients of thermal expansion between the sc-SiC and p-SiC layers, which can be significant due to different doping levels in the two layers. This thickness also limits the deformation (warping) of the substrate to be fabricated, consisting of a 30-layer p-SiC layer and a thin 20-layer sc-SiC layer. Furthermore, the thinner the sc-SiC layer, the less energy is required to generate the embrittlement regions used for transfer. Therefore, transferring thin sc-SiC layers is easier and more energy-efficient.

[0072] Graphite possesses a coefficient of thermal expansion close to that of single-crystal and polycrystalline silicon carbide. Therefore, it is particularly suitable as a temporary support substrate material for fabricating substrates involving high-temperature steps. These high-temperature steps include, for example, stripping a donor substrate during sc-SiC layer transfer, depositing a p-SiC layer, such as by vapor deposition, and any recrystallization and relaxation heat treatments and subsequent processing. Furthermore, graphite can be readily removed, for example, by grinding, chemical etching, and / or combustion. Therefore, there is no need to optimize the surface quality and adhesion of the sc-SiC layer to facilitate the removal of the temporary support substrate at the end of the process.

[0073] The temporary support substrate must be smooth enough to maintain the sc-SiC layer without significant surface deformation during the deposition of the p-SiC layer. However, this method does not impose any limitations on the structure and quality of the graphite used, since the temporary support substrate is removed to complete the silicon carbide substrate.

[0074] Bonding protects the temporary support substrate from the risk of it peeling off during high-temperature steps. Those skilled in the art will know how to select the type of bond based on the expected temperature and environment in the process. Since bonding is only temporary, the associated constraints are relatively minor. The sole purpose of bonding is to ensure the mechanical integrity of the sc-SiC layer during p-SiC layer deposition. Therefore, there is no need to optimize the electrical or thermal conductivity through the bond interface.

[0075] Therefore, p-SiC layers can be deposited at temperatures selected based on the desired properties of the p-SiC layer. There is no need to limit temperature windows or other process parameters to prevent the sc-SiC layer from peeling off its support. For example, thermal treatments for dopant activation and mechanical stress relaxation can also be performed without any specific constraints imposed by the temporary support substrate.

[0076] The thickness of each p-SiC layer ranges from 100 μm to 2 mm. Such a thickness is sufficient to allow the substrate to be self-supporting over its entire area after the temporary support substrate is removed.

[0077] The fact that the p-SiC layer is deposited directly on a thin sc-SiC layer with good crystal quality allows for high-quality p-SiC deposition across the entire thickness of that layer. This avoids the need for an additional step of removing a portion of the p-SiC. After p-SiC is deposited onto the sc-SiC surface with good crystal quality, the interface between the corresponding p-SiC and sc-SiC layers exhibits good mechanical, electrical, and thermal coupling.

Claims

1. A method for manufacturing a substrate (300), the substrate (300) comprising a polycrystalline silicon carbide layer (30, 30A, 30B) and a single-crystal silicon carbide layer (20, 20A, 20B) in direct contact with the polycrystalline silicon carbide layer, the method comprising the following sequential steps: o Transfer the first single-crystal silicon carbide layer (20, 20A) to the front side of the graphite temporary support substrate (10), Polycrystalline silicon carbide is deposited onto the first single-crystal silicon carbide layer (20, 20A) to form the polycrystalline silicon carbide layer (30, 30A). o Remove the temporary graphite support substrate (10).

2. The manufacturing method of claim 1, further comprising transferring a second single-crystal silicon carbide layer (20B) onto the back side of the temporary support substrate (10) prior to the step of depositing polycrystalline silicon carbide, wherein the step of depositing polycrystalline silicon carbide comprises forming a second polycrystalline silicon carbide layer (30B) on the second single-crystal silicon carbide layer (20B).

3. The manufacturing method according to claim 1 or claim 2, the method comprising applying an adhesive layer between each single-crystal silicon carbide layer (20A, 20B) and the temporary support substrate (10).

4. The manufacturing method as described in any of the preceding claims, wherein the step of transferring each single-crystal silicon carbide layer (20, 20A, 20B) onto the temporary support substrate (10) comprises the following steps: o By implanting atomic material into a single-crystal silicon carbide donor substrate (200) to form an embrittlement region (21), o The donor substrate (200) is bonded to the free surface of the temporary support substrate (10). o Peel the donor substrate (200) along the embrittlement region (21) to transfer the single-crystal silicon carbide layer (20, 20A, 20B) onto the temporary support substrate (10).

5. The manufacturing method according to any one of the preceding claims, wherein, The deposition of each polycrystalline silicon carbide layer (30, 30A, 30B) is performed by chemical vapor deposition.

6. The manufacturing method according to any one of the preceding claims, the method further comprising performing heat treatment at a temperature higher than the deposition temperature after depositing a polycrystalline silicon carbide layer (30, 30A, 30B).

7. The manufacturing method as described in claim 6, wherein, The heat treatment is carried out at a temperature greater than or equal to 1700°C.

8. The manufacturing method as described in any of the preceding claims, wherein, The step of removing the temporary support substrate (10) includes burning the graphite at a temperature of 800°C to 900°C under an oxygen flow.

9. The manufacturing method as described in any of the preceding claims, wherein, The step of removing the temporary support substrate (10) includes chemical etching or oxygen plasma etching.

10. The manufacturing method according to any one of the preceding claims, wherein, The step of removing the temporary support substrate (10) includes a polishing step.

11. The manufacturing method according to any one of the preceding claims, wherein, The thickness of the temporary support substrate (10) is 1 to 15 mm.

12. The manufacturing method according to any one of the preceding claims, wherein, The thickness of the first single-crystal silicon carbide layer (20, 20A) is 400 nm to 5 μm, preferably 400 nm to 2 μm, and more preferably 400 nm to 1 μm.

13. The manufacturing method according to any one of the preceding claims, wherein, The thickness of the first polycrystalline silicon carbide layer (30, 30A) is 100 μm to 2 mm.

14. The manufacturing method as described in any of the preceding claims, wherein, The front side of the graphite temporary support substrate (10) has a first dimension, and the first single-crystal silicon carbide layer has a second dimension less than or equal to half of the first dimension, such that the first layer forms a first block (20C). The method further includes transferring at least a second single-crystal silicon carbide block (20D, 20E) onto the front side of the temporary support substrate (10), such that the first block and the second block (20C, 20D, 20E) are arranged side by side on the front side of the temporary support substrate (10). The step of depositing the polycrystalline silicon carbide layer includes forming a corresponding polycrystalline silicon carbide layer on each block (20C, 20D, 20E).

15. An intermediate substrate comprising: o Graphite temporary support substrate (10), o The first single-crystal silicon carbide layer (20, 20A) disposed on the front side of the temporary support substrate (10), and o A first polycrystalline silicon carbide layer (30, 30A) is arranged to be in direct contact with the first single-crystal silicon carbide layer (20, 20A).

16. The intermediate substrate as claimed in claim 15, wherein, The thickness of the single-crystal silicon carbide layer (20, 20A) is 400 nm to 5 μm, preferably 400 nm to 2 μm, more preferably 400 nm to 1 μm, and the thickness of the polycrystalline silicon carbide layer (30, 30A) is 100 μm to 2 mm.

17. The intermediate substrate as claimed in claim 15 or claim 16, wherein, The graphite temporary support substrate (10) has a first dimension on its front side, and the first single-crystal silicon carbide layer has a second dimension that is less than or equal to half of the first dimension, such that the first layer forms a first block (20C). The intermediate substrate further includes at least a second single-crystal silicon carbide block (20D, 20E), such that the first block and the second block (20C, 20D, 20E) are arranged side by side on the front side of the temporary support substrate (10), and the polycrystalline silicon carbide layer is arranged on each single-crystal silicon carbide block (20C, 20D, 20E).

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