JP2895179B2 - Vapor phase synthesis method of diamond single crystal thin film - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for synthesizing a diamond thin film by a chemical reaction of a reaction gas.

[Prior Art] Demand for diamond thin films applied to electronic materials, optical materials, carbide tools and the like has recently increased.

As a diamond thin film manufacturing technology, CVD (Che
A technique called “mical vapor deposition” has recently attracted attention. This method uses a heated filament or plasma to decompose and ionize a hydrocarbon compound such as methane gas (CH ₄ ),
It grows a diamond-like carbon film on a semiconductor or ceramic substrate.

It is also reported that a diamond single crystal or a cubic boron nitride single crystal can be used to grow a single crystal diamond thin film.

[Problems to be Solved by the Invention] However, most of the diamond thin films obtained by the conventional methods such as the CVD method are polycrystalline films composed of aggregates of diamond fine particles, and it is difficult to obtain single crystal films.
This was mainly because the crystal structure and crystal lattice constant of the substrate were significantly different from those of diamond.

According to the method of selecting a substrate as in the latter, single crystal substrates are extremely expensive for both diamond and boron nitride at present, and furthermore, high quality diamonds satisfying practical requirements of a substrate having a size of about 1 cm ² or more. Alternatively, there is a problem that a single crystal substrate of boron nitride does not exist. Therefore, according to the conventional method, it was difficult to obtain a high-quality diamond single crystal thin film required for a light emitting device or an electronic device.

Therefore, an object of the present invention is to provide a method capable of inexpensively synthesizing a high-quality, large-area, diamond single-crystal thin film.

[Means and Actions for Solving the Problems] The invention of claim 1 provided to solve the problems includes the following steps: (a). A raw material gas containing a gas containing a carbon element and a gas containing a silicon element is supplied to a silicon single crystal substrate to synthesize a cubic silicon carbide single crystal thin film having a thickness of 100 to 5000 mm on the silicon single crystal substrate. Step, wherein the raw material gas contains the gas containing the carbon element and the gas containing the silicon element in the range of 0.1% to 5% by volume in the total gas; and (b).
By supplying a raw material gas containing a gas containing a carbon element and not containing a gas containing a silicon element to the substrate on which the cubic silicon carbide single crystal thin film is synthesized, diamond is formed on the cubic silicon carbide single crystal thin film on the substrate. Synthesizing a single crystal thin film, wherein the source gas contains a gas having the carbon element in a range of 0.1% by volume to 5% by volume in the total gas; It is a gas phase synthesis method.

Claim 2 is provided to solve the problem.
The invention comprises the following steps: (a). A step of synthesizing a cubic silicon carbide single crystal thin film having a thickness of 2 mm or more and 500 mm or less on a silicon single crystal substrate by supplying a source gas containing a gas containing a carbon element and a gas containing a silicon element to the silicon single crystal substrate; The source gas contains the gas containing the carbon element and the gas containing the silicon element in the range of 0.1% by volume to 5% by volume, respectively, in the total gas; and (b). By supplying a raw material gas containing a gas containing a silicon element and not containing a gas containing a carbon element to the substrate,
A step of synthesizing a silicon single crystal thin film having a thickness of not less than {500} and not more than 500%, wherein the source gas contains a gas containing the silicon element in a range of 0.1% by volume to 5% by volume in the whole gas;
(A). Step (b).
After repeating a series of steps at least twice or more, the step (a). A cubic silicon carbide single crystal thin film and a silicon single crystal thin film are alternately deposited by performing a process, and a cubic silicon carbide single crystal thin film having a thickness of 2 mm or more and 500 mm or less is synthesized on the outermost surface. Synthesizing a multilayer film of 5000 ° or less on the silicon single crystal substrate, further comprising the following steps: (c). A step of synthesizing a single-crystal diamond thin film on the multilayer film by supplying a source gas containing a gas containing a carbon element and not containing a gas containing a silicon element to the substrate, wherein the source gas contains the carbon element Wherein the gas contained in the gas is contained in the range of 0.1% by volume to 5% by volume of the total gas; thus, a diamond single crystal thin film is synthesized on the multilayer film. This is a phase synthesis method.

Claim 3 is provided to solve the problem.
The invention comprises the following steps: (a). A step of synthesizing a cubic silicon carbide single crystal thin film having a thickness of 2 mm or more and 500 mm or less on a silicon single crystal substrate by supplying a source gas containing a gas containing a carbon element and a gas containing a silicon element to the silicon single crystal substrate; The source gas contains the gas containing the carbon element and the gas containing the silicon element in the range of 0.1% by volume to 5% by volume, respectively, in the total gas; and (b). By supplying a raw material gas containing a gas containing a carbon element and not containing a gas containing a silicon element to the substrate,
A process of synthesizing a diamond thin film of Å to 500Å,
Here, the raw material gas contains the gas containing the carbon element in a range of 0.1% by volume to 5% by volume in the total gas; and (a). Step (b). A series of steps is repeated at least twice or more to form a multilayer film having a thickness of 100 mm or more and 5000 mm or less formed by alternately depositing a cubic silicon carbide single crystal thin film and a diamond thin film on the silicon single crystal substrate. And further synthesizing the following steps: (c). A step of synthesizing a single-crystal diamond thin film on the multilayer film by supplying a source gas containing a gas containing a carbon element and not containing a gas containing a silicon element to the substrate, wherein the source gas contains the carbon element Wherein the gas contained in the gas is contained in the range of 0.1% by volume to 5% by volume of the total gas; thus, a diamond single crystal thin film is synthesized on the multilayer film. This is a phase synthesis method.

Claim 4 is provided to solve the problem.
The invention comprises the following steps: (a). A step of synthesizing a cubic silicon carbide single crystal thin film having a thickness of 2 mm or more and 100 mm or less on a silicon single crystal substrate by supplying a source gas containing a gas containing a carbon element and a gas containing a silicon element to the silicon single crystal substrate; The source gas contains the gas containing the carbon element and the gas containing the silicon element in the range of 0.1% by volume to 5% by volume, respectively, in the total gas; and (b). By supplying a raw material gas containing a gas containing a silicon element and not containing a gas containing a carbon element to the substrate,
A step of synthesizing a silicon single crystal thin film having a thickness of {100} or less, wherein the source gas contains a gas containing the silicon element in a range of 0.1% by volume to 5% by volume in the whole gas;
(A). Step (b).
A series of steps is repeated at least twice or more to synthesize a multilayer film formed by alternately depositing a cubic silicon carbide single crystal thin film and a silicon single crystal thin film on the silicon single crystal substrate. Step (c). A raw material gas containing a gas containing a carbon element and a gas containing a silicon element is supplied to the substrate to synthesize a cubic silicon carbide single crystal thin film having a thickness of 2 to 100 mm on the substrate on which the multilayer film is formed. Step, wherein the raw material gas is a gas containing the carbon element and a gas containing the silicon element each in 0.1% of the total gas.
% In the range of 5% to 5% by volume; and (c). Following the process (d). A step of synthesizing a diamond thin film having a thickness of 2 mm or more and 100 mm or less on the substrate on which the multilayer film is formed by supplying a raw material gas containing a gas containing a carbon element and not containing a gas containing a silicon element to the substrate; Wherein the raw material gas contains the gas having the carbon element in a range of 0.1% by volume to 5% by volume in the whole gas;
Is repeated at least twice or more, and a cubic silicon carbide single crystal thin film and a silicon single crystal thin film are alternately deposited, and a cubic silicon carbide single crystal thin film and a diamond thin film are alternately formed thereon. Thickness of 100 deposited on
Synthesizing a multilayer film having a thickness of not less than {5000} on the silicon single crystal substrate, and further comprising the following steps: (e). A step of synthesizing a single-crystal diamond thin film on the multilayer film by supplying a source gas containing a gas containing a carbon element and not containing a gas containing a silicon element to the substrate, wherein the source gas contains the carbon element Wherein the total gas content is in the range of 0.1% by volume to 5% by volume; thereby forming a diamond single crystal thin film on the multilayer film. This is a synthesis method.

The reason why the silicon carbide single crystal thin film having the cubic structure is synthesized on the silicon single crystal substrate prior to the synthesis of the diamond single crystal thin film in claim 1 is as follows.

In other words, silicon single crystal has a diamond structure, but its lattice constant is 5.43Å, which is the lattice constant of diamond.
Because it is significantly different from 3.57Å, it is not possible to synthesize a diamond single crystal thin film directly on a silicon single crystal substrate.

On the other hand, cubic silicon carbide has a zinc-blende structure similar to a diamond structure, and its lattice constant is 4.36 °, which is an intermediate value between silicon and diamond. Therefore, a silicon carbide single crystal thin film can be directly synthesized on a silicon single crystal substrate. The silicon carbide single crystal thin film synthesized on the silicon single crystal substrate has a zinc-blende structure similar to the diamond structure, and thus can inherit the diamond structure of the silicon single crystal substrate. Furthermore, its lattice constant is 4.36Å, which is close to 3.57Å for diamond. Therefore, it is possible to synthesize a diamond single crystal thin film on this silicon carbide single crystal thin film. Further, since the thin film has a property in which the lattice is deformed in the in-plane direction and absorbs a difference in lattice constant with the substrate, generation of crystal defects can be suppressed. That is, the cubic silicon carbide single crystal thin film in claim 1 functions as a buffer film that takes over the lattice structure of the silicon single crystal substrate while relaxing the strain due to lattice mismatch between the silicon single crystal substrate and the diamond single crystal. I have.

5. The method according to claim 2, wherein prior to synthesizing the diamond single-crystal thin film, synthesizing each of the multilayer films on the silicon single-crystal substrate, because each of the multi-layers functions as the buffer film. This is because it is possible to synthesize a diamond single crystal thin film. By using a multilayer film in which the ultrathin films are stacked in multiple layers as the buffer film, the effect of suppressing the occurrence of crystal defects by the thin film is further improved.

That is, in claim 2, the multilayer film functioning as a buffer film is formed by alternately depositing a cubic silicon carbide single crystal thin film and a silicon single crystal thin film. In this case, a high quality multilayer film can be synthesized. It is easy, and the function as the buffer film is further improved because the lattice constant changes gradually as compared with the first embodiment. That is, in this case, since the average lattice constant of the multilayer film is an intermediate value between silicon and silicon carbide, the lattice constant difference between the multilayer buffer film and silicon is smaller than that in the first embodiment, and the multilayer film is formed. Since the thickness of each layer is thin and sufficiently thin as described above, accumulation of strain due to the difference in lattice constant is reduced, and crystal defects can be easily prevented. As a result, the function as the buffer film is further improved.

In the third aspect, the multi-layer is formed by alternately depositing a cubic silicon carbide single crystal thin film and a diamond thin film, and the lattice constant changes more gradually than in the first aspect. Better. That is, in this case, since the average lattice constant of the multilayer film is an intermediate value between silicon carbide and diamond, the difference in lattice constant between the multilayer buffer film and diamond becomes smaller than in the case of claim 1, and the multilayer film is formed. Since the thickness of each layer is thin and sufficiently thin as described above, accumulation of strain due to the difference in lattice constant is reduced, and crystal defects can be easily prevented. As a result, the function as the buffer film is further improved.

The multilayer film according to claim 4, wherein a cubic silicon carbide single crystal thin film and a silicon single crystal thin film are alternately deposited, and a cubic silicon carbide single crystal thin film and a diamond thin film are alternately deposited thereon. Since the change of the constant is performed more gradually than in the first to third aspects, the function as a buffer film is further improved. Therefore, it is possible to synthesize a higher quality diamond single crystal thin film.

Further, according to claim 1, the thickness of the cubic silicon carbide single crystal thin film synthesized on the silicon single crystal substrate is 100 ° or more and 500 ° or more.
The reason why the thickness is set to 0 ° or less is that when the thickness is 100 ° or less, the function as the buffer film is small. On the other hand, if the thickness is 5000 mm or more, the effect as a bulk becomes dominant, and the function as the buffer film is small. The thickness of the cubic silicon carbide single crystal thin film is more preferably 500 to 100
0Å.

The thickness of the thin film of cubic silicon carbide, silicon or diamond is set to 2 ° or more and 100 ° or more because the multilayer film formed by depositing these thin films can function as the buffer layer. This is because the above thickness is required, and a more preferable thickness of these thin films is 10 mm.
~ 50Å. Then, in principle, each thin film can be formed as a single atomic layer. In this case, however, the multilayer film is a so-called artificial mixed crystal.

And the thickness of the multilayer film is 100
The reason why the thickness is not less than Å and not more than 5000 た め is that the above-mentioned thickness is required in order that the multilayer film can function as the buffer tank. More preferred thickness of the multilayer film is 500 to 1000
Å.

In order to adjust the thickness of each of the single-crystal thin films described above and to set each range as described in claims 1 to 4, for example, by adjusting the time for supplying a raw material for synthesizing each thin film to the substrate. There are ways to do it.

Further, in the claims 2 to 4, the step consisting of (a) and (b) is repeated at least twice or more.
In step (c) and step (d),
The reason why the number of repetitions is more than twice is to allow the multilayer film synthesized by these steps to function as the buffer layer, and the number of repetitions for further improving the function of the multilayer film as the buffer layer. Is preferably 5 times or more.

Various conventional methods may be used for synthesizing the silicon carbide, silicon and diamond thin films according to claims 1 to 4, for example, a microwave CVD method and a plasma CVD method.
Method, a CVD method called a hot filament method, a combustion flame method, an ion beam method, or the like.

In the case where a cubic silicon carbide single crystal thin film is synthesized on a silicon single crystal substrate according to claims 1 to 4, a raw material having a carbon element such as hydrogen gas, methane (CH ₄ ) gas and silane (SiH ₄ ) gas are used. In this case, the content of the gas of the raw material containing the carbon element and the content of the gas of the raw material containing the silicon element in the total gas are 0.1% by volume to 5% by volume, respectively. It is preferable that the volume ratio between the raw material gas containing the carbon element and the raw material gas containing the silicon element is 0.2 to 1.0: 1.

In the case of synthesizing a silicon single crystal thin film on a cubic silicon carbide single crystal thin film according to claim 2 or 3, it can be synthesized by using a raw material having a silicon element such as hydrogen gas and silane gas. The content of the raw material gas containing silicon element is preferably set to 0.1% by volume to 5% by volume in the total gas.

In the case where the diamond single crystal thin film is synthesized on the silicon carbide single crystal thin film according to claims 1 to 3, the synthesis can be performed by using a raw material having a carbon element such as hydrogen gas and methane gas. The content of the raw material gas containing the element is 0.1% by volume to 5% of the total gas.
Preferably, it is set to volume%.

In the first to fourth aspects of the present invention, the silicon single crystal substrate means that the entire substrate is a single crystal of silicon and that the substrate surface is made of a single crystal of silicon. Silicon single crystal can be obtained at a low cost with high quality and a large area. Therefore, by synthesizing the buffer film on this substrate, a high-quality, large-area diamond single-crystal thin film can be synthesized at low cost.

The thickness of the diamond thin film can be set to a thickness suitable for the intended use. The thickness is several hundred μm or more for tools and heat sinks, and 100 mm for optical films and semiconductor devices.
To about several μm.

Example 1 Example 1 Next, an example in which the method of the present invention is embodied will be described with reference to FIG. FIG. 1 shows an example of a reactor suitable for carrying out the method of the present invention in a simplified form. In the apparatus shown in FIG. 1, reference numeral 1 denotes a cylindrical reaction vessel, which is provided with three supply pipes 2a, 2b, 2c for supplying three kinds of gaseous raw materials at an upper portion of one side thereof. An exhaust port 3 is provided at the lower part of the side surface that is parallel. The reaction vessel 1
Inside, a silicon single crystal substrate 5 placed on a substrate holder 4 is arranged at a position substantially facing the openings of the supply pipes 2a, 2b, 2c. A normal microwave oscillator 6 is provided outside the reaction vessel 1 and at a position corresponding to a position vertically below the substrate holder 4, and is used for supplying microwaves oscillated from the microwave oscillator 6 to the substrate 5. Wave waveguides 7 are provided outside the reaction vessel 1 so as to face vertically upper and lower portions of the substrate holder 4.

Per minute of hydrogen gas from the supply pipe 2a in the case of producing diamond thin film in the first embodiment, a silane gas (SiH ₄₎ methane gas (CH ₄₎ from 10 cc / min and the supply pipe 2c from the supply pipe 2b 8 cc / In the reaction vessel 1 at a rate of 1 / min.
With the pressure reduced to 80 Torr, a microwave (frequency: 2.45 GHz, power: about 100 W) from the microwave oscillator 6 is guided onto the silicon single crystal substrate 5 by the microwave waveguide 7, and the silicon substrate 5 is heated to 1300 ° C. Hold for about 10 minutes.

Next, the supply of the silane gas from the supply pipe 2c was stopped, and the temperature of the substrate 5 was lowered to about 1000 ° C. by changing the microwave power condition, and was maintained for about 1 hour.

FIG. 2 is a graph showing the cross-sectional structure of the substrate 5 and the film M obtained by observing the film M obtained on the silicon substrate 5 by transmission electron microscopy and surface electron diffraction as a result of the above operation, and its lattice constant. Shown in The unit of the lattice constant in FIG. 2 is Å, and the same applies to the following description.

As shown in FIG. 2, a cubic silicon carbide single crystal thin film 8 (lattice constant 4.36) having a thickness of about 1200 ° is formed on a silicon single crystal substrate 5 having a lattice constant of 5.43. A diamond single crystal thin film 9 (lattice constant 3.57) was formed. When this diamond single crystal thin film 9 was evaluated by Raman scattering, a strong peak was observed at 1333 cm ⁻¹ , confirming that it was diamond.

Example 2 Using the same apparatus shown in FIG. 1 as in Example 1, each source gas was supplied as follows to produce a diamond thin film.

That is, the pressure inside the reaction vessel 1 was similarly reduced to about 80 Torr, and the silicon substrate 5 was heated to about 1000 ° C. by the microwave (frequency 2.45 GHz) from the micro oscillator 6. First, hydrogen gas was supplied from the supply pipe 2a at a rate of 1 minute per minute, propane gas was supplied from the supply pipe 2b at a rate of 10 cc / min, and monochlorosilane was supplied from the supply pipe 2c at a rate of 7 cc / min into the reaction vessel 1 for 50 seconds. Thereafter, the supply of propane gas from the supply pipe 2b was stopped, and only hydrogen gas (1 / min) and monochlorosilane (7 cc / min) were supplied for 50 seconds. The above operation was defined as one cycle, and this cycle was repeated seven cycles. Then, after supplying three kinds of gases at the same ratio as above for 50 seconds, the supply of monochlorosilane from 2c was stopped in the future, and hydrogen gas (1 / min) and propane gas (10 cc /
Min) only for 50 seconds. The above operation was defined as one cycle, and this cycle was repeated seven cycles. Thereafter, supply of only hydrogen gas (1 / min) and propane gas (10 cc / min) was performed for about 1 hour.

The graph showing the cross-sectional structure of the substrate 5 and the film M obtained by examining the film M obtained on the silicon substrate 5 by transmission electron microscopy observation and surface electron diffraction according to the third operation is shown in FIG. Shown in the figure.

As shown in FIG. 3, the silicon substrate 5 (with a lattice constant of 5.
43) First, a silicon carbide-silicon multilayer film A is formed, and a silicon carbide-diamond multilayer film B is formed on the multilayer film A.
Was formed, and a diamond single crystal film 9 having a thickness of about 15 μm was formed on the multilayer film B.

The silicon carbide-silicon multilayer film A has a structure in which a silicon single crystal thin film 10 (lattice constant 5.43) having a thickness of about 70 ° is formed on a cubic silicon carbide single crystal thin film 8 (lattice constant 4.36) having a thickness of about 100 °. The unit is one cycle, and is formed by repeating seven cycles. The silicon carbide-diamond multilayer film B has a structure in which a diamond thin film 11 (lattice constant 3.57) having a thickness of about 100 mm is formed on a cubic silicon carbide single crystal thin film 8 (lattice constant 4.36) having a thickness of about 50 mm. 1 unit
A cycle is formed by repeating this seven cycles.

Further, as a result of measuring the film 9 on the uppermost surface by the Raman scattering method, a strong peak was observed at 1333 cm ⁻¹ , confirming that the film was a diamond single crystal thin film. The distribution of the silicon (Si) element and the carbon (C) element in the depth direction of the multilayer film was measured by secondary ion mass spectrometry, and a clear periodicity corresponding to the result of transmission electron microscope observation was obtained. Was observed, and it was estimated that the interdiffusion between Si and C was extremely small.

The method described in the above embodiment is a method known as a so-called microwave CVD method. However, other plasma CVD method and a hot filament method of the present invention also include a combustion flame method and an ion beam method. It is needless to say that the same structure as in the embodiment can be realized by supplying and stopping the carbon raw material and the silicon raw material.

The conditions in this embodiment are as follows: the flow rate of the total gas consisting of hydrogen gas, methane gas, and silane gas is 0.1 / min or more, and the amount of each of the methane gas or silane gas contained in the total gas is 0.1% by volume or more. 5% by volume,
It is preferable that the volume ratio of methane gas to silane gas at the time of synthesizing the carbon silicon thin film is 0.2 to 1 with respect to 1 silane gas.

The pressure range in the reaction vessel can be set to 10 Torr to 760 Torr (1 atm). When the pressure is close to 1 atm, it becomes difficult to control the flow of gas.

Furthermore, in the present embodiment, the power of the microwave depends on the device such as the shape of the substrate and the shape of the reaction tube.
Can be in the range of W. The microwave wave number is, for example, 1GH
z to several hundred GHz. The substrate temperature is preferably in the range of 700C to 1000C.

By selecting the above conditions, the production speed of the silicon carbide, silicon or diamond single crystal thin film or the quality of the diamond single crystal thin film can be further improved.

[Effects of the Invention] According to the invention of claims 1 to 4, the cubic silicon carbide single crystal thin film or each multilayer film synthesized on the silicon single crystal substrate functions as a buffer film. It is possible to synthesize a high-quality diamond single crystal thin film in which the presence, distortion and crystal defects of crystals are prevented as much as possible. Further, since the elements constituting the substrate and the buffer film are both group VI elements, even if solid phase diffusion occurs, the influence on the film characteristics is extremely small. As the silicon used as the substrate, a single crystal of high quality and large area can be obtained at low cost.
Therefore, according to the first to fourth aspects of the present invention, a high-quality and large-area diamond single-crystal thin film required for a light-emitting element or an electronic element can be easily synthesized at low cost, and greatly contributes to the development of new electronic components. I can do it.

According to the second or third aspect of the present invention, a buffer film is formed by alternately depositing a cubic silicon carbide single crystal thin film and a silicon single crystal thin film or a multilayer film alternately depositing a cubic silicon carbide single crystal thin film and a diamond thin film. Since it functions and the lattice constant is gradually changed, distortion and crystal defects caused by the difference in lattice constant are more effectively prevented, and a diamond single crystal thin film with higher quality can be synthesized.

According to the invention of claim 4, both of the two types of multilayer films function as buffer films, and the lattice constant changes more gradually, so that a diamond single crystal thin film with further improved quality can be synthesized.

[Brief description of the drawings]

FIG. 1 to FIG. 3 relate to an embodiment, FIG. 1 is a simplified side sectional view of a reactor, and FIGS. 2 and 3 are obtained by the first or second embodiment, respectively. FIG. 2 is a schematic cross-sectional view of a film and a silicon substrate and a graph showing its lattice constant. DESCRIPTION OF SYMBOLS 1 ... Reaction container 2a, 2b, 2c ... Supply pipe 5 ... Silicon substrate 6 ... Microwave oscillator 8 ... Cubic silicon carbide single crystal thin film 9 ... Diamond single crystal thin film 10 ... Silicon single crystal thin film 11 ... Diamond thin film A ... Cubic Silicon carbide-silicon multilayer film B ... Cubic silicon carbide-diamond multilayer film

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Takashi Matsuda 2-4-1 Rokuno, Atsuta-ku, Nagoya-shi, Aichi Japan Fine Ceramics Center Testing Laboratory (56) References JP-A-63-286576 (JP) , A) JP-A-61-106494 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) C30B 1/00-35/00

Claims (4)

(57) [Claims] 1. The following steps: (a). By supplying a raw material gas containing a gas containing a carbon element and a gas containing a silicon element to a silicon single crystal substrate, a thickness of 100
工程 a step of synthesizing the following cubic silicon carbide single crystal thin film, wherein the raw material gas is a gas containing the carbon element and a gas containing the silicon element in the range of 0.1% by volume to 5% by volume in the total gas. And (b). By supplying a raw material gas containing a gas containing a carbon element and not containing a gas containing a silicon element to the substrate on which the cubic silicon carbide single crystal thin film is synthesized, diamond is formed on the cubic silicon carbide single crystal thin film on the substrate. A step of synthesizing a single crystal thin film, wherein the source gas contains a gas having the carbon element in a range of 0.1% by volume to 5% by volume in the total gas. Gas phase synthesis method. 2. The following steps: (a). A step of synthesizing a cubic silicon carbide single crystal thin film having a thickness of 2 mm or more and 500 mm or less on a silicon single crystal substrate by supplying a source gas containing a gas containing a carbon element and a gas containing a silicon element to the silicon single crystal substrate; Wherein the source gas contains the gas containing the carbon element and the gas containing the silicon element in a range of 0.1% by volume to 5% by volume in the total gas; and (b). A step of synthesizing a silicon single crystal thin film having a thickness of 2 mm or more and 500 mm or less on the substrate by supplying a raw material gas containing a gas containing a silicon element and not containing a gas containing a carbon element to the substrate; Contains a gas containing the silicon element in a range of 0.1% by volume to 5% by volume in the total gas; and (a). Step (b). After repeating the series of steps at least twice or more,
Further, (a). A cubic silicon carbide single crystal thin film and a silicon single crystal thin film are alternately deposited by performing a process, and a cubic silicon carbide single crystal thin film having a thickness of 2 mm or more and 500 mm or less is synthesized on the outermost surface. Synthesizing a multilayer film of 5000 ° or less on the silicon single crystal substrate, further comprising the following steps: (c). A step of synthesizing a single-crystal diamond thin film on the multilayer film by supplying a source gas containing a gas containing a carbon element and not containing a gas containing a silicon element to the substrate, wherein the source gas contains the carbon element A total of 0.1% by volume to 5% by volume of the gas contained in the gas to synthesize a diamond single crystal thin film on the multilayer film. Phase synthesis method. 3. The following steps: (a). A step of synthesizing a cubic silicon carbide single crystal thin film having a thickness of 2 mm or more and 500 mm or less on a silicon single crystal substrate by supplying a source gas containing a gas containing a carbon element and a gas containing a silicon element to the silicon single crystal substrate; Wherein the source gas contains the gas containing the carbon element and the gas containing the silicon element in a range of 0.1% by volume to 5% by volume in the total gas; and (b). A step of synthesizing a diamond thin film having a thickness of 2 mm or more and 500 mm or less on the substrate by supplying a raw material gas containing a gas containing a carbon element and not containing a gas containing a silicon element to the substrate, wherein the raw material gas is: Wherein the gas containing the carbon element is contained within a range of 0.1% by volume to 5% by volume in the total gas; and (a). Step (b). A series of steps is repeated at least twice or more to form a multilayer film having a thickness of 100 mm or more and 5000 mm or less formed by alternately depositing a cubic silicon carbide single crystal thin film and a diamond thin film on the silicon single crystal substrate. Synthesizing and further comprising the following steps: (c). A step of synthesizing a single-crystal diamond thin film on the multilayer film by supplying a source gas containing a gas containing a carbon element and not containing a gas containing a silicon element to the substrate, wherein the source gas contains the carbon element A total of 0.1% by volume to 5% by volume of the gas contained in the gas to synthesize a diamond single crystal thin film on the multilayer film. Phase synthesis method. 4. The following steps: (a). A step of synthesizing a cubic silicon carbide single crystal thin film having a thickness of 2 mm or more and 100 mm or less on a silicon single crystal substrate by supplying a source gas containing a gas containing a carbon element and a gas containing a silicon element to the silicon single crystal substrate; The raw material gas contains a gas containing the carbon element and a gas containing the silicon element in the range of 0.1% by volume to 5% by volume, respectively, in the total gas; and (b). A step of synthesizing a silicon single crystal thin film having a thickness of 2 to 100 mm on the substrate by supplying a raw material gas containing a gas containing a silicon element and not containing a gas containing a carbon element to the substrate; Contains a gas containing the silicon element in a range of 0.1% by volume to 5% by volume in the total gas; and (a). Step (b). A series of steps is repeated at least twice or more to synthesize a multilayer film formed by alternately depositing a cubic silicon carbide single crystal thin film and a silicon single crystal thin film on the silicon single crystal substrate. Step (c). A raw material gas containing a gas containing a carbon element and a gas containing a silicon element is supplied to the substrate to synthesize a cubic silicon carbide single crystal thin film having a thickness of 2 to 100 mm on the substrate on which the multilayer film is formed. Wherein the source gas contains the gas containing the carbon element and the gas containing the silicon element in the range of 0.1% to 5% by volume in the total gas, respectively; and (c). Following the process (d). A step of synthesizing a diamond thin film having a thickness of 2 to 100 mm on the substrate on which the multilayer film is formed by supplying a raw material gas containing a gas containing a carbon element and not containing a gas containing a silicon element to the substrate, The source gas contains 0.1% by volume of the gas containing the carbon element in the total gas.
Is repeated at least twice or more, and a cubic silicon carbide single crystal thin film and a silicon single crystal thin film are alternately deposited and cubic thereon. Thickness of 100 deposited by alternately depositing single crystal silicon carbide thin film and diamond thin film
Synthesizing a multilayer film having a thickness of not less than {5,000} on the silicon single crystal substrate, and further comprising the following steps: (e). A step of synthesizing a diamond single-crystal thin film on the multilayer film by supplying a source gas containing a gas containing a carbon element and not containing a gas containing a silicon element to the substrate, wherein the source gas contains the carbon element A total of 0.1% to 5% by volume of the gas contained in the gas to synthesize a diamond single crystal thin film on the multilayer film. Phase synthesis method.