JP2004103671A - METHOD OF MANUFACTURING SiC FILM THROUGH EPITAXIAL GROWTH - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the occurrence of crystal defects caused by lattice mismatching and strains caused by differences in thermal expansion in a method by which an SiC film is manufactured on an Si substrate through epitaxial growth. <P>SOLUTION: The method by which the SiC film is epitaxially grown on the Si substrate includes a step (a) of forming a c-BP (cubic boron phosphide) layer on the Si substrate as a buffer layer, a step (b) of forming an amorphous SiC film on the buffer layer through epitaxial growth at a temperature lower than the crystallization temperature of SiC, and a step (c) of performing annealing at the forming temperature of the c-BP layer or lower by stopping the supply of a gaseous starting material. The method also includes a step (d) of forming a crystalline 3C-SiC film on the amorphous SiC film through epitaxial growth at the crystallization temperature of SiC or higher. In this method, the SiC film is grown by using the single-layered BP film formed by the method or multilayered BP and SiC films formed by repeating the method as the buffer layer. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for producing a SiC film by epitaxial growth. In particular, the present invention relates to a method suitable for manufacturing a SiC single crystal film used for a power device element and a high-frequency semiconductor element.
[0002]
[Related technologies]
A 3C-SiC single crystal film used for a power device or a high-frequency element is manufactured using a Si substrate having a zinc blende structure similar to 3C-SiC in crystal structure.
[0003]
At present, research on growing 3C-SiC on a Si substrate for power devices has been conducted. The reason is as follows.
[0004]
(A) The crystal perfection of Si is extremely high. (B) A large-diameter crystal substrate can be obtained at low cost. (C) The processing line for manufacturing Si devices can be used. However, a crystal film having a different lattice constant from the substrate is used. In the case where is grown, stress is generated due to lattice mismatch between the target crystal substance and the substrate and a difference in thermal expansion, and polycrystallization and crystal defects occur frequently, so that a good crystal cannot be obtained.
[0005]
Therefore, a method of forming an intermediate layer between the substrate and the crystal film of the target substance to alleviate lattice mismatch, or a method of carbonizing or undulating the surface of the Si substrate with a hydrocarbon gas to roughen the surface, followed by silane or propane gas For example, a method of epitaxially growing 3C—SiC has been proposed.
[0006]
[Problems to be solved by the invention]
There is a lattice mismatch between Si serving as a substrate and SiC to be grown, which causes a large number of crystal defects due to misfit dislocations, which is a problem during device fabrication.
[0007]
Therefore, in order to grow a crystal film having a lattice constant different from that of the substrate, it is necessary to suppress and relax the lattice mismatch between the target crystal material and the substrate and the stress due to the difference in thermal expansion.
[0008]
There is a method in which the surface of an Si substrate is carbonized with a hydrocarbon gas, and SiC is grown using the carbonized gas as a buffer layer. According to this method, a phenomenon is observed in which Si atoms in the substrate are carried away to the surface of the substrate by the carbonization treatment, holes are generated in the Si substrate, and the Si substrate is roughened.
[0009]
In addition, it has been proposed to obtain a large-diameter 3C-SiC single crystal by subjecting a Si substrate to undulation and roughening the surface thereof to offset and reduce a number of defects.
[0010]
However, in such a vapor phase growth, since the surface state of the substrate is inherited, a high-quality single crystal layer having a low defect density and a low quality cannot be obtained, and none satisfying the requirements as a device substrate has yet been obtained. Also, the roughness of the substrate can be an electrical resistance during device fabrication.
[0011]
Therefore, it is necessary to provide a buffer layer of an appropriate substance that does not cause the substrate to be roughened, and a method of heteroepitaxially growing SiC using c-BP, which is a zinc blende type crystal, as an intermediate layer has been proposed. In this method, since c-BP decomposes at a temperature lower than the SiC growth temperature, a technique has been proposed in which an amorphous layer such as SiC is formed at a temperature lower than the decomposition start temperature to suppress the decomposition as a shielding film against an atmospheric gas. .
[0012]
However, 3C-SiC crystals for use as devices are required to have further improved crystallinity. In addition, defect propagation from the c-BP layer as the buffer layer to the SiC layer has been confirmed, and improvement in the crystallinity of the buffer layer is also desired.
[0013]
That is, it is necessary to eliminate as much as possible crystal defects at the interface with the SiC layer even when the substrate is subjected to the undulation process or the method of introducing the intermediate buffer layer. Therefore, it is desired to establish a crystal growth method for obtaining a 3C-SiC crystal film having few defects by vapor-phase growth using Si as a substrate while avoiding suppression of such a lattice constant difference and a thermal expansion difference.
[0014]
An object of the present invention is to provide a method for manufacturing a high-quality SiC film by improving the crystallinity of a c-BP layer formed as a buffer layer on a Si substrate and further reducing the difference in thermal expansion.
[0015]
[Means for Solving the Problems]
An example of the solution of the present invention is as follows.
[0016]
(1) a step of forming cubic boron phosphide (c-BP) as a buffer layer on a Si substrate;
A step of forming an amorphous SiC film on the buffer layer by epitaxial growth at a temperature lower than the temperature at which SiC crystallizes, and a step of forming a 3C-SiC crystal film on the amorphous SiC film at a temperature higher than the temperature at which SiC crystallizes. Forming a film by epitaxial growth.
[0017]
(2) The method according to (1), wherein after the formation of the amorphous SiC film at the low temperature, the supply of the raw material gas is stopped to perform an annealing process, and thereafter, the 3C-SiC crystal film is formed at the high temperature. Method for producing SiC film.
[0018]
(3) The method for producing a SiC film according to the above (1) or (2), wherein the film forming temperature of the amorphous SiC is 300 to 650 ° C.
[0019]
(4) The method for producing a SiC film according to (2), wherein the annealing temperature after the formation of the amorphous SiC is equal to or lower than the film forming temperature of c-BP.
[0020]
(5) A method of epitaxially growing a SiC film on a Si substrate, comprising the following steps.
[0021]
(A) A raw material gas containing a gas containing a P (phosphorus) element and a gas containing a B (boron) element is supplied onto a Si substrate to synthesize an amorphous BP thin film having a thickness of 5 nm or more and 100 nm or less on the Si substrate. Process,
(B) a step of supplying a raw material gas containing a gas containing a P element and a gas containing a B element on the Si substrate to synthesize a c-BP single crystal thin film having a thickness of 5 nm or more and 1000 nm or less on the Si substrate; ,
(C) A gas having a carbon element and a gas having a silicon element are supplied onto the Si substrate on which the c-BP single crystal thin film has been synthesized, and a thickness of 1 nm is formed on the c-BP single crystal thin film on the Si substrate. A step of synthesizing an amorphous SiC thin film having a thickness of 500 nm or less,
(D) annealing the Si substrate at a temperature of 750 to 1200 ° C. to improve the crystallinity of the c-BP single crystal film formed in the step (b);
(E) a step of supplying a gas containing a carbon element and a silicon element again onto the Si substrate to synthesize a 3C-SiC single crystal thin film having a thickness of 1 nm or more and 500 nm or less.
[0022]
(6) A method further comprising the following step in the step (5).
[0023]
(F) By repeating the above-described series of steps (a) to (e) at least twice or more, a c-BP single crystal thin film and a 3C-SiC single crystal thin film are alternately deposited to have a thickness of 10 nm or more and 1 μm. Forming the following multilayer film on a Si substrate,
(G) a step of supplying a raw material gas containing a gas containing a carbon element and a gas containing a silicon element to the Si substrate on which the multilayer film is formed, to synthesize a 3C-SiC single crystal film having a thickness of 1 μm or more.
[0024]
BEST MODE FOR CARRYING OUT THE INVENTION
According to a preferred embodiment of the present invention, an amorphous layer of SiC is formed on a buffer layer at a temperature equal to or lower than a BP decomposition start temperature, and functions as a shielding film with an atmosphere. Is stopped, and annealing is performed at a BP film forming temperature or lower. Thereby, the crystallinity of c-BP of the buffer layer is improved, and a good 3C-SiC growth film can be obtained even in the subsequent growth of the SiC single crystal.
[0025]
In epitaxially growing a SiC single crystal film on Si serving as a substrate, c-BP is used as an intermediate buffer layer. It is known that c-BP can be heteroepitaxially grown on Si although the lattice constant of c-BP, which is a zinc blende type crystal, is different from that of Si by 16.4% compared with the lattice constant. By epitaxially growing c-BP on a Si substrate, cubic silicon carbide (3C-SiC) crystal having a lattice constant close to the lattice constant of c-BP can be heteroepitaxially grown while suppressing misfit dislocations. However, since the SiC crystal layer takes over the crystal defects of the intermediate buffer layer as its base, it is necessary to improve the crystallinity of the intermediate buffer layer. Further, since SiC itself cannot obtain a remarkable crystal improving effect by annealing at a low temperature, it is important to improve the crystal in a c-BP buffer layer capable of obtaining an annealing effect even at a low temperature.
[0026]
Here, a P-containing material such as c-BP decomposes at a temperature lower than the melting point, which hinders subsequent heteroepitaxial growth. Therefore, after epitaxially growing c-BP, an SiC amorphous layer is grown at a relatively low temperature of 300 to 650 ° C. to about 500 nm, and then the substrate temperature is increased from 750 ° C. to a temperature lower than the c-BP growth temperature to anneal. Perform Thereafter, crystal growth of 3C-SiC is performed at a predetermined temperature. It is effective that the annealing temperature is as close as possible to the SiC crystal growth temperature.
[0027]
By providing the amorphous SiC layer at a relatively low temperature, the decomposition of c-BP is suppressed, and the temperature can be raised to a temperature at which the annealing effect can be exhibited. Annealing after low-temperature growth of SiC suppresses BP decomposition, improves the crystallinity of the c-BP layer, and improves the buffer layer to obtain a high-quality SiC heteroepitaxial crystal.
[0028]
As the above-mentioned application, the buffer layer and the SiC layer are thinly and multi-layered and interposed to reduce the thermal expansion difference.
[0029]
First, a BP amorphous thin film having a thickness of 5 nm or more and 100 nm or less is synthesized on a Si substrate by supplying a raw material gas containing a gas having an adjacent element and a gas having a boron element on the Si substrate at a low temperature. Here, the source gas contains the gas containing the phosphorus element and the gas containing the boron element in the total gas in the range of 0.01 to 30% by volume. The film formation temperature is 300 to 700 ° C.
[0030]
Next, the temperature is increased, and a source gas containing a gas containing an adjacent element and a gas containing a boron element is supplied onto the substrate. Thus, a c-BP single crystal thin film having a thickness of 5 nm or more and 1000 nm or less is synthesized on the Si substrate. Here, the source gas contains the gas containing the phosphorus element and the gas containing the boron element in the total gas in the range of 0.01 to 30% by volume. The film forming temperature is 800 to 1200 ° C.
[0031]
Here, the temperature is lowered, and a gas containing a carbon element and a gas containing a silicon element are supplied to the Si substrate on which the c-BP single crystal thin film has been synthesized. Thereby, an amorphous SiC thin film having a thickness of 1 nm or more and 300 nm or less is synthesized on the c-BP single crystal thin film on the Si substrate. The raw material gas used here contains a gas containing a carbon element and a gas containing a silicon element within the range of 0.01 to 30% by volume in the total gas. The film forming temperature at that time is 300 to 650 ° C.
[0032]
After that, the source gas is stopped, and the substrate is annealed at a temperature of 750 ° C. or more and a c-BP deposition temperature or less to improve the crystallinity of the cubic boron phosphide single crystal film formed earlier.
[0033]
A gas containing a carbon element and a silicon element is supplied again onto the substrate to synthesize a 3C-SiC single crystal thin film having a thickness of 1 nm to 500 nm. The raw material gas used here contains a gas containing a carbon element and a gas containing a silicon element within the range of 0.01 to 30% by volume in the total gas. The film forming temperature is 800 to 1100 ° C.
[0034]
The above series of steps is repeated at least twice or more to form a multilayer film having a thickness of 10 nm or more and 10000 nm or less formed by alternately depositing a c-BP single crystal thin film and a 3C-SiC single crystal thin film on a Si substrate. .
[0035]
Further, a source gas containing a gas containing a carbon element and a gas containing a silicon element is supplied to the substrate. Thereby, a 3C-SiC single crystal film of 1 μm or more is synthesized on the substrate. The raw material gas used here contains a gas containing a carbon element and a gas containing a silicon element within the range of 0.01 to 30% by volume in the total gas. The film forming temperature is 800 to 1200 ° C.
[0036]
【Example】
Hereinafter, examples of the present invention will be described.
[0037]
Example 1
(1) Heat the Si substrate in a hydrogen atmosphere at 1000 ° C. or higher. Thereby, the natural oxide film is removed.
[0038]
(2) c-BP crystal growth is performed. That is, the temperature of the Si substrate is raised to 800 to 1000 ° C., and B ₂ H ₆ and PH ₃ are supplied as raw material gases to the surface of the Si substrate to increase the temperature of the substrate to 0. A c-BP film having a thickness of about 5 μm is formed.
[0039]
(3) A low-temperature growth layer of SiC is provided on the c-BP film. That is, while subjected supercharges PH _3, the temperature was lowered to 300 to 600 ° C., stopping the supply of PH ₃ 3, monomethyl silane _{(CH 3} SiH 3) supplied as SiC raw material gas, a thickness of about 0.2μm Is formed.
[0040]
(4) The raw material gas is stopped and annealing is performed at 800 ° C. which is lower than the c-BP growth temperature.
[0041]
(5) 3C-SiC crystal growth is performed. That is, the temperature is raised to 750 to 900 ° C., monomethylsilane (CH ₃ SiH ₃ ) is supplied again, and 3C—SiC is deposited to a thickness of 5 μm or more.
[0042]
Comparative Example 1
As Comparative 1, a film was formed without annealing. That is, a film was formed in the same manner as in Example 1 except for (4) of Example 1 described above.
[0043]
Comparative Example 2
As Comparative 2, a film was formed by annealing at 1020 ° C. which is higher than the c-BP growth temperature. That is, the annealing temperature in (4) of Example 1 was changed.
[0044]
FIG. 1 shows a diffraction pattern of X-ray diffraction evaluation results of the crystals prepared in Example 1 and Comparative Examples 1 and 2 described above. FIG. 2 graphically illustrates it as a diffraction intensity comparison.
[0045]
As is clear from FIGS. 1 and 2, after forming the c-BP layer, an amorphous SiC layer is formed at a low temperature, the c-BP layer is shielded from the atmosphere by the amorphous SiC layer, and after annealing, 3C- In Example 1 in which the SiC layer was grown, a higher quality 3C-SiC heteroepitaxial crystal could be obtained as compared with Comparative Example 1 without annealing. However, when the annealing temperature was equal to or higher than the c-BP film forming temperature as in Comparative Example 2, the c-BP layer was decomposed, and the crystallinity of c-BP and 3C-SiC was deteriorated.
[0046]
Therefore, after the c-BP is grown on the Si substrate, the deterioration of the c-BP is suppressed by providing the SiC low-temperature growth layer, and further, the c-BP layer is annealed at a temperature lower than the c-BP film forming temperature. After improving 3C-SiC crystal growth, a high-quality heteroepitaxial crystal can be obtained.
[0047]
Example 2
Second Embodiment A multilayer film according to a second embodiment will be described with reference to FIGS.
[0048]
3 (a) and 3 (b) are a plan view and a longitudinal sectional view, respectively, showing a simplified example of a reactor suitable for carrying out the method of the present invention.
[0049]
In the apparatus shown in FIG. 3, reference numeral 1 denotes a reaction vessel having a circular or rectangular cross section, and three supply spaces 2a, 2b, and 2c for supplying three kinds of gaseous raw materials are provided at the starting end side in this order from the top. Have been. An exhaust port 3 is provided at the end side opposite to the start end side. In the reaction tube 1, a Si single crystal substrate 5 placed on a susceptor 4 is disposed at a position substantially facing the openings of the two supply tubes 2 b and 2 c. Under the susceptor 4, a carbon heating element 6 for heating the Si substrate 5 is provided. The susceptor 4 is rotatable as shown by an arrow in FIG.
[0050]
A method for manufacturing a 3C-SiC film using the apparatus shown in FIG. 3 will be described below.
[0051]
The silicon substrate 5 is heated to 300 to 500 ° C. by the carbon heating element 6 and held for 10 to 30 minutes while the pressure inside the reaction vessel 1 is reduced to 150 Torr by a pressure reducing means (not shown) following the exhaust port 3. 1 liter of hydrogen gas per minute from the supply pipe 2a, 10 cc of B ₂ H ₆ from the water-cooled supply pipe 2b per minute, and PH ₃ from the supply pipe 2c with a built-in heating element 2e and temperature controllable. 1 liter is supplied into the reaction vessel 1 to synthesize an amorphous BP single crystal thin film having a thickness of 5 nm or more and 100 nm or less on the Si substrate 5.
[0052]
Next, the Si substrate 5 is heated to 800 to 1100 ° C. by the carbon heating element 6 and maintained for 10 to 30 minutes while the pressure in the reaction vessel 1 is reduced to 150 Torr. 1 liter of hydrogen gas per minute from the supply pipe 2a, 10 cc of B ₂ H ₆ from the water-cooled supply pipe 2b per minute, and 1 liter of PH ₃ from the supply pipe 2c with a built-in heating element 2e and temperature controllable. A c-BP single crystal thin film having a thickness of 5 nm or more and 1 μm or less is synthesized by supplying a nozzle into the reaction tube and further supplying a source gas containing a gas having an adjacent element and a gas having a boron element on the substrate. I do.
[0053]
Next, a gas containing a carbon element and a gas containing a silicon element are supplied to the Si substrate 5 on which the c-BP single crystal thin film has been synthesized. First, the Si substrate 5 is heated to 300 to 650 ° C. by the carbon heating element 6 and held for 10 to 30 minutes in a state where the pressure inside the reaction vessel 1 is reduced to 150 Torr. At that time, 5 liters of hydrogen gas per minute from the supply pipe 2a and 6 cc of CH ₃ SiH ₃ per minute from the supply pipe 2c having a built-in heating element 2e and capable of controlling the temperature are supplied into the reaction vessel 1, and the Si substrate 5 An amorphous SiC thin film having a thickness of 1 nm or more and 100 nm or less is synthesized on the c-BP single crystal thin film.
[0054]
The Si substrate 5 is annealed at a temperature of 750 to 1100 ° C. to improve the crystallinity of the previously formed c-BP single crystal film.
[0055]
Next, a gas containing a carbon element and a silicon element is supplied onto the Si substrate 5 again. First, the Si substrate 5 is heated to 800 to 1100 ° C. by the carbon heating element 6 and held for 10 to 120 minutes while the pressure inside the reaction vessel 1 is reduced to 0.001 Torr. At this time, 5 liters of hydrogen gas per minute from the supply pipe 2a and 6 cc of CH ₃ SiH ₃ per minute from the supply pipe 2c having a built-in heating element 2e and capable of controlling the temperature are supplied into the reaction vessel 1 to be 1 nm to 500 nm. The following 3C-SiC single crystal thin film is synthesized.
[0056]
By repeating the above-described series of steps at least twice or more, the c-BP single crystal thin film and the 3C-SiC single crystal thin film are alternately deposited. Thereby, a multilayer film having a thickness of 10 nm or more and 10 μm or less is formed on the Si substrate.
[0057]
Further, a source gas containing a gas containing a carbon element and a gas containing a silicon element is supplied to the Si substrate 5. First, the Si substrate 5 is heated to 800 to 1200 ° C. by the carbon heating element 6 and held for 300 minutes while the pressure inside the reaction vessel 1 is reduced to 0.001 Torr. At this time, 5 liters of hydrogen gas per minute from the supply pipe 2a and 6 cc of CH ₃ SiH ₃ per minute from the supply pipe 2c having a built-in heating element 2e and capable of controlling the temperature are supplied into the reaction vessel 1, and the Si substrate 5 is supplied. A 2 μm 3C—SiC single crystal film is synthesized thereon.
[0058]
FIG. 4 is a cross-sectional view schematically showing a 3C-SiC crystal on a Si substrate obtained by an example of the present invention, and FIG. 5 is a graph showing a typical X-ray diffraction evaluation result. FIGS. 4 and 5 show a case where a 3C-SiC single crystal film is grown particularly thick. FIG. 4A shows an example in which the buffer layer is a single layer, and FIG.
[0059]
A multilayer film formed by alternately depositing a c-BP single crystal thin film and a 3C-SiC single crystal thin film grown on the Si single crystal substrate 5 functions as a buffer film (buffer layer), and has a c-BP layer formed by an annealing effect. , The crystallinity of the 3C-SiC film formed on each c-BP is gradually improved and improved. In addition, the difference between the lattice constant and the coefficient of thermal expansion is effectively reduced, and a high-quality 3C-SiC single crystal film in which distortion and crystal defects are prevented as much as possible can be formed on the Si substrate 5. . In FIG. 5, it is clear from the fact that the diffraction intensity is improved in the case of the multilayer structure.
[0060]
Although the example in which the 3C-SiC crystal is formed on the Si substrate has been described, the crystal layer formed on the Si substrate can be applied to all compound crystals such as GaN, nitride, and oxide.
[Brief description of the drawings]
FIG. 1 is a diffraction pattern of an X-ray diffraction evaluation result of a crystal prepared on a silicon substrate according to an example of the present invention and Comparative Examples 1 and 2. FIG. 2 is a diffraction intensity of an X-ray diffraction evaluation result of FIG. (A) is a plan view showing a simplified example of a reactor suitable for carrying out the method of the present invention, and (b) is a plan view showing a simplified example of a reactor suitable for carrying out the method of the present invention. FIG. 4 is a cross-sectional view schematically showing a 3C-SiC crystal on a Si substrate obtained according to an embodiment of the present invention. (A) has a single buffer layer, and (b) has a multilayer buffer layer.
FIG. 5 is a representative X-ray diffraction evaluation result of a 3C—SiC single crystal film grown thick on a Si substrate in FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Reaction tube 2a, 2b, 2c Supply tube 2e Heating element 3 Exhaust port 4 Susceptor 5 Si substrate 6 Carbon heating element

Claims (6)

Forming a film of cubic boron phosphide (c-BP) as a buffer layer on the Si substrate;
A step of forming an amorphous SiC film on the buffer layer by epitaxial growth at a temperature lower than the temperature at which SiC crystallizes, and a step of forming a 3C-SiC crystal film on the amorphous SiC film at a temperature higher than the temperature at which SiC crystallizes. Forming a film by epitaxial growth. 2. The SiC film according to claim 1, wherein after forming the amorphous SiC film at the low temperature, the supply of the source gas is stopped to perform an annealing process, and thereafter, the 3C-SiC crystal film is formed at the high temperature. Production method. The method for producing a SiC film according to claim 1, wherein a film forming temperature of the amorphous SiC is 300 to 650 ° C. 4. 3. The method for producing a SiC film according to claim 2, wherein the annealing temperature after the formation of the amorphous SiC is equal to or lower than the film forming temperature of c-BP. A method for epitaxially growing a SiC film on a Si substrate, comprising the following steps.
(A) A raw material gas containing a gas containing a P (phosphorus) element and a gas containing a B (boron) element is supplied onto a Si substrate to synthesize an amorphous BP thin film having a thickness of 5 nm to 100 nm on the Si substrate. Process,
(B) A raw material gas containing a gas containing a P element and a gas containing a B element is further supplied onto the Si substrate to synthesize a c-BP single crystal thin film having a thickness of 5 nm or more and 1000 nm or less on the Si substrate. Process,
(C) A gas having a carbon element and a gas having a silicon element are supplied onto the Si substrate on which the c-BP single crystal thin film has been synthesized, and a thickness of 1 nm is formed on the c-BP single crystal thin film on the Si substrate. A step of synthesizing an amorphous SiC thin film having a thickness of 500 nm or less,
(D) annealing the Si substrate at a temperature of 750 to 1200 ° C. to improve the crystallinity of the c-BP single crystal film formed in the step (b);
(E) supplying a gas containing a carbon element and a silicon element again onto the Si substrate to synthesize a 3C-SiC single crystal thin film having a thickness of 1 nm or more and 500 nm or less; The method of claim 5, comprising the following steps.
(F) By repeating the above-described series of steps (a) to (e) at least twice or more, a c-BP single crystal thin film and a 3C-SiC single crystal thin film are alternately deposited to have a thickness of 10 nm or more and 1 μm. Forming the following multilayer film on a Si substrate,
(G) a step of supplying a raw material gas containing a gas containing a carbon element and a gas containing a silicon element to the Si substrate on which the multilayer film is formed, to synthesize a 3C-SiC single crystal film having a thickness of 1 μm or more.

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