JPH0597581A - Method for synthesizing diamond and synthesizing device used therefor - Google Patents

Abstract

PURPOSE:To readily and stably synthesize various diamond thin films and to obtain a synthesizing device useful for the synthesis. CONSTITUTION:A vapor-phase growth part 30 to synthesize a diamond thin film is connected to a film quality control part 31, the vapor-phase growth part 30 is provided with openings 13 and 13'. Laser beam 12 from the film quality control part 31 is passed through the opening 13, irradiated to a substrate 8 arranged in a reaction tube 5 and scattering light or emission 14 from the substrate 8 is observed by its passage through the opening 13'. The film quality control part 31 is provided with a spectrometer 15 and a light detector 16 of observing and detecting the scattered light or emission 14 and further equipped with a data treating device 17 for treating results obtained by the light detector 16 and controlling synthetic conditions of diamond thin film.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a diamond synthesizing method using a vapor phase growth method and a synthesizing apparatus used therefor.

[0002]

2. Description of the Related Art Diamond has excellent properties such as hardness, thermal conductivity, and insulating properties, and is utilized in various fields by making the best use of each property. In recent years, diamond thin films or diamond-like thin films have been synthesized by the CVD method (vapor phase growth method). This allows for cutting tools,
It is attracting attention as a material for high-performance materials such as optical materials and semiconductor materials as well as protective films for wear-resistant tools.

Various methods for synthesizing a diamond thin film by vapor phase epitaxy have been developed so far, but as a method for obtaining a film having a film quality that can be used as a high-performance material, Japanese Patent Laid-Open No. 58-91100 has been disclosed. The hot filament CVD method disclosed and the microwave plasma CVD method disclosed in JP-A-58-110494 are mentioned. The diamond film synthesized by these methods needs to have a film quality suitable for various uses. For example, the coating on the sliding member needs to be a smooth film in which graphite is mixed to some extent. On the contrary, materials that use optical and electrical properties such as optical materials and semiconductor materials must have high crystallinity with few impurities and crystal defects. Coatings for cemented carbide tools, which take advantage of their high hardness, are located just in the middle of these and require a film with relatively good crystallinity. Further, depending on a special application, it may be necessary to sequentially change the film quality in the film thickness direction.

As described above, diamond thin films having various film qualities are required depending on the use, and film forming conditions suitable for each of them must be determined. Therefore, the time required for condition setting becomes very long.

On the other hand, in the synthesis of diamond thin film,
The film quality may change significantly due to a slight change in the film forming conditions. For example, when the carbon-containing compound concentration in the source gas is 0.1%, and when the substrate temperature is 2
The film quality changes with a difference of about 0 ° C. Further, when the hot filament method is used, it is more difficult to set the conditions due to the change of the filament with time. Thus, it is a difficult problem to stably synthesize a diamond thin film having a constant film quality.

As a means for solving such a problem, as in "High quality diamond and its manufacturing method" disclosed in Japanese Patent Application Laid-Open No. 2-248396, after checking the film quality of the diamond synthesized for a certain period of time, There is a method of forming a film again.

[0007]

However, in the above-mentioned "high quality diamond and its manufacturing method", the reaction must be interrupted at regular intervals to take out the product,
There is a problem in that the loss of time due to this is large. In addition, since the film quality cannot be known until a certain period of time elapses, there is a possibility that the film may be formed under conditions completely different from the target film quality up to that point, and this problem is not essentially solved. Absent.

An object of the present invention is to solve the above-mentioned problems and to stably supply a diamond film having a desired film quality.

[0009]

According to the diamond synthesis method of the present invention, when a diamond thin film is synthesized on a substrate by a vapor phase growth method, the diamond thin film is irradiated with light and the light from the diamond thin film is detected. It is characterized in that synthesis is performed while controlling the membrane conditions. The light to be detected is preferably scattered light or emitted light from the diamond thin film, or absorbed light.

On the other hand, a diamond synthesizing apparatus for carrying out the above-mentioned synthesizing method comprises a vapor phase reaction means for synthesizing a diamond thin film by a vapor phase growth method and a film quality for irradiating the diamond thin film with light to control film forming conditions. The gas phase reaction means has at least one opening through which light for irradiating the diamond thin film passes, and the film quality control means observes the light source for irradiating the diamond thin film and the light from the diamond thin film. And a data processing device for controlling the film forming conditions of the diamond thin film for processing the result obtained by the light detecting part and transmitting it to the above-mentioned vapor phase reaction means. The light from the diamond thin film is preferably scattered light, emitted light, or absorbed light.

[0011]

The present inventors conducted extensive research to develop a method capable of easily and stably forming diamond thin films having various film qualities. As a result, the diamond thin films synthesized were excited by the laser beam and the film qualities. It was discovered that there is a certain relationship between the light emission from the diamond thin film or the wavelength of light absorbed by the diamond thin film itself. This phenomenon is 1333 cm, which was used in the conventional diamond measurement.
^-1 Raman scattered light is included, but not only that, but it was found from the ultraviolet region to the infrared region.

[0012] For example, in the case of the light emitting, taking the Raman scattered light as an example, the stronger the peak intensity of 1333 cm ^-1 diamond film quality (crystallinity) may, strong and non-diamond component is a peak of 1600 cm ^-1 (Graphite It can be said that the component) increases. Although the peak position of light emission during diamond synthesis changes depending on the substrate temperature during synthesis,
It has been found that an observable signal can be obtained at the diamond synthesis temperature or lower.

In the case of observing absorbed light, when visible absorption is measured, the absorption starts from the short wavelength part when the graphite component increases (when the crystallinity deteriorates). In this case as well, it was found that although the position of the absorption edge changes depending on the substrate temperature during diamond synthesis, an observable signal can be obtained at the diamond synthesis temperature or lower.

By utilizing the above knowledge in the present invention, the above-mentioned problems can be solved.

That is, while synthesizing a diamond thin film,
By observing the detection light of the light irradiated to the diamond thin film, especially the scattered light, the peak position and peak intensity of the emission, or the absorption edge of the absorbed light, the film quality of the diamond thin film can be known during synthesis. Membrane conditions can be controlled. Therefore, a film quality suitable for the purpose can be obtained without interrupting the synthesis.

Further, in the synthesizer using the above method,
The gas phase reaction means is provided with an opening so that the diamond thin film can be irradiated with light, and the film quality control means observes the detected light from the diamond thin film, especially scattered light or luminescence, or absorbed light, and processes the result. A data processing device for transmitting to the gas phase reaction means is installed. Therefore, while synthesizing the diamond thin film, it is possible to control the film forming conditions for obtaining the film quality according to the purpose.

[0017]

DETAILED DESCRIPTION OF THE INVENTION FIG. 1 shows a first structure of a synthesizing apparatus using the synthesizing method of the present invention, and is a conceptual diagram of a microwave plasma CVD apparatus.

As shown in the figure, this synthesizer comprises a vapor phase growth section 30 and a film quality control section 31. To the reaction tube 5 which is the main part of the vapor phase growth part 30, flow rate controllers 18, 18 'for feeding the raw material gas into the reaction tube 5 and the raw material gas introduction tube 4 are connected. 9 is installed, on which a substrate 8 for synthesizing thin films is arranged. Further, the reaction tube 5 is fixed in an applicator 3 having a rectangular waveguide 2, and the rectangular waveguide 2 guides the microwave generated by the magnetron 1 to form a plasma on the substrate 8. It is positioned so that it can go straight in the tube 2. The applicator 3 can irradiate the substrate 8 with light from a laser oscillation device (for example, a helium neon laser device) 10 installed outside, and can also emit scattered light or light emission from the substrate 8. Two openings 13, 13 'are provided so that they can be observed.

A film quality control unit 31 for controlling the film quality of the diamond thin film to be synthesized is connected to the vapor phase growth unit 30 centering on the reaction tube 5. Spectrometer 15 and photodetector 16 for observing and detecting scattered light or light emission from the substrate 8.
And a data processing device 17 for processing the results obtained by the photodetector to control the conditions for synthesizing the diamond thin film.

In the diamond thin film synthesizing method using the above-mentioned synthesizing apparatus, first, the raw material gas is passed through the raw material gas introducing pipe 4 through the flow rate controllers 18 and 18 ', and the reaction is set in the applicator 3. Introduced into tube 5. The inside of the reaction tube 5 is set to a predetermined pressure, and the raw material gas is exhausted from an exhaust port 6 provided at the bottom of the reaction tube 5. Next, the microwave generated by the magnetron 1 goes straight through the inside of the rectangular waveguide 2 and is reflected by the plunger 7 to form plasma around the substrate 8 on the substrate holder 9 installed in the reaction tube 5. To do. As a result, a diamond thin film is synthesized on the substrate 8. At this time, the laser light 12 oscillated from the laser oscillator 10 is applied to the diamond thin film being synthesized, and scattered light or light emission 14 generated from the diamond thin film is measured by the photodetector 16. At this time, the film quality such as crystallinity and non-diamond mixture is evaluated, and the film formation conditions are adjusted so that a film having a desired film quality can be synthesized. By this method, a diamond thin film having a film quality suitable for the intended use can be stably obtained. Although it is installed so as to adjust the source gas ratio and the microwave power here, the purpose can be achieved by changing the pressure, the position of the substrate, and the like.

FIG. 2 shows a second structure of the synthesizing apparatus using the synthesizing method of the present invention, and is a conceptual diagram of the microwave plasma CVD apparatus.

As shown in the figure, this synthesizer comprises a vapor phase growth section 30 and a film quality control section 31. The structure of the vapor phase growth part 30 is basically the same as the above-mentioned first structure, but the reaction tube 5 has a lamp 10 installed outside.
A light incident window 19 is provided in place of the openings 13 and 13 ′ so that light from 0 can be irradiated onto the substrate 81. The lamp 100 is not limited to the tungsten lamp, and may be any light emitter in the ultraviolet to visible range.

A film quality control means 31 for the diamond thin film is installed outside the vapor phase growth part 30 centering on the reaction tube 5. The film quality control means 31 is provided with a spectroscope 15 and a photodetector 16 for observing and detecting the light transmitted through the substrate 81. Further, the results obtained by the photodetector 16 are processed to process the diamond thin film. A data processing device 17 that controls the synthesis condition is installed.

The diamond synthesizing method using the above-mentioned synthesizing apparatus is performed in the same manner as the method used in the above-mentioned first structure. First, the raw material gas passes through the raw material gas introduction pipe 4 via the flow rate controllers 18, 18 ′ and is introduced into the reaction pipe 5 installed in the applicator 3. The inside of the reaction tube 5 is set to a predetermined pressure, and the raw material gas is exhausted from an exhaust port 6 provided in the lower part of the reaction tube 5. Next, the microwave generated by the magnetron 1 goes straight through the inside of the rectangular waveguide 2 and is reflected by the plunger 7 to form plasma around the substrate 8 on the substrate holder 9 installed in the reaction tube 5. To do. As a result, a diamond thin film is synthesized on the base 81. At this time, visible light 120 from the lamp 100 is applied to the diamond thin film being synthesized, and the transmitted light is measured by the photodetector 16 through the optical fiber 21. At this time, the film quality is evaluated and the film forming conditions are adjusted so that a film having a desired film quality can be synthesized. By this method, a diamond thin film with stable film quality can be obtained.

The diamond synthesis conditions of the present invention including the above-mentioned first and second configurations use a carbon-containing compound gas and hydrogen as raw material gases. The carbon-containing compound gas is not particularly limited as long as it contains carbon. Examples thereof include hydrocarbons such as methane, ethane, propane, ethylene and acetylene, oxygen-containing carbon compounds such as methanol, ethanol, acetone and carbon monoxide, and chlorine-containing carbon compounds such as carbon tetrachloride and methyl chloride. Among these, methane, acetylene, ethanol and the like are preferable because they are easy to handle and decompose.

The mixing ratio of the carbon-containing compound and hydrogen is not particularly limited, but the carbon-containing compound / hydrogen = 0.001 to 0.2.
Is preferred. If it is less than 0.001, no film is formed,
If it exceeds 0.2, it becomes graphite.

The substrate is preferably one that is not damaged at the diamond synthesis temperature of 600 ° C. or higher. For example, it is a metal such as molybdenum or tungsten, a semiconductor such as silicon, or a ceramic such as quartz alumina. Alternatively, diamond may be used.

The substrate temperature is preferably 300 to 1200 ° C. When the temperature is lower than 300 ° C. or higher than 1200 ° C., the diamond film formation rate is remarkably reduced or the diamond film is not formed.

The pressure can be in the range of 0.1 to 760 Torr, but in view of the film forming speed and the film quality, it is 10 to 100To.
rr is preferred.

The material of the substrate holder is required to withstand a high temperature to some extent. Specifically, ceramics and refractory metals are preferable. For ceramics, boron nitride (BN), alumina, silicon nitride, etc. are desirable. Although metal is easy to process, when using the microwave plasma CVD method, plasma discharge may be disturbed in some cases. As the metal, stainless steel, molybdenum, tungsten or the like is preferable.

Although the structure of the present invention has been described using the conventional microwave plasma CVD method, it goes without saying that any method can be used as long as it is a diamond synthesis method.

[0032]

【Example】

Example 1 Diamond having few impurities and good crystallinity was stably synthesized using the apparatus shown in FIG. In this example,
The oscillation frequency of the magnetron 1 is 2.45 GHz, the size of the rectangular waveguide 2 is 110 × 55 mm, the size of the applicator 3 is 135 × 78 mm, the reaction tube 5 is made of quartz and the inner diameter is 40 mmφ, and the substrate 8 is made of silicon and is 20 mm. The corner and the base holder 9 are made of quartz, and the wavelength of the laser beam 12 is 633.
nm, and the openings 13 and 13 'had a diameter of 10 mm.

In the synthesis method using the apparatus shown in FIG. 1, first, 100 sccm of a mixed gas of methane / hydrogen = 1%, which is controlled by the flow rate controllers 18 and 18 'from the raw material gas introduction pipe 4, is used.
The pressure was set to 30 torr. The microwave generated by the magnetron 1 was oscillated at 200 W, guided by the rectangular waveguide 2, and then reflected by the plunger 7 to form a standing wave in the reaction tube 5 installed in the applicator 3. As a result, plasma was formed around the substrate 8 made of silicon on the substrate holder 9 installed in the reaction tube 5, and a diamond thin film was synthesized on the substrate 8. Substrate temperature is about 8
It was 00 ° C.

At this time, diamond having good crystallinity (having a small amount of non-diamond components) is synthesized as a desired film quality. 1320c as the measurement wavelength for film quality evaluation
Raman peak of diamond at m ^-1 was used. This peak wavelength is shifted due to the high temperature of 800 ° C., but it is about 1333 cm ^{−1 at} room temperature. While monitoring the intensity of this peak, the microwave power and raw material gas ratio were adjusted to maximize the intensity. If the microwave power is too low or too high, diamond with good crystallinity cannot be synthesized, and there is an optimum value. On the other hand, with respect to the gas ratio, the crystallinity is improved as the methane concentration is decreased, but in that case, the film formation rate is significantly reduced. Here, the film with good crystallinity was adjusted to maximize the methane concentration. 4 in this way
The film was formed for a time.

SEM (scanning electron microscope) of grown film
The photograph is shown in FIG. From this, it was found that a diamond film having good crystallinity can be synthesized by using this method. Example 2 Using the apparatus shown in FIG. 3, homoepitaxial diamond containing few impurities and few defects was stably synthesized. In this embodiment, the oscillation frequency of the magnetron 1 is 2.45 GHz and the size of the rectangular waveguide 2 is 110 × 55.
mm, the size of the applicator 3 is 135 × 78 mm, the reaction tube 5 is made of quartz and has an inner diameter of 40 mmφ, the substrate 8 is a 2 mm square diamond substrate (plane orientation (100)), and the hollow substrate holder 20 is aluminum nitride (AlN). The light introduction window 19 was made of synthetic quartz.

In the synthesis method using the apparatus of FIG. 3, first,
A mixed gas of methane / hydrogen = 6% controlled by the flow rate controllers 18 and 18 'is supplied from the raw material gas introduction pipe 4 at 100 sccc.
m flow and the pressure was set to 30 torr. The microwave generated by the magnetron 1 is oscillated at 200 W, and the rectangular waveguide 2
After being guided by, the light is reflected by the plunger 7 to form a standing wave in the reaction tube 5 installed in the applicator 3.
Thereby, the hollow substrate holder 2 installed in the reaction tube 5
Plasma is formed around the substrate 81 on the
A diamond thin film is epitaxially grown on it. The substrate temperature was about 800 ° C.

At this time, the synthesized diamond was irradiated with visible light and the transmitted light was monitored, and the microwave power and the raw material gas ratio were adjusted so that there was no absorption. In the case of epitaxial growth, there are optimum values for both microwave power and source gas ratio. When non-diamond component growth was observed, it was removed by etching. The film was formed by such a method for 4 hours.

RHEED of grown epitaxial film
(Reflection High Energy Electron Diffraction) pattern is shown in FIG. From this, it was found that a diamond film with few defects can be easily synthesized by this method. Example 3 Diamond having few impurities and good crystallinity was stably synthesized using the apparatus shown in FIG. Note that FIG. 5 is a conceptual diagram of a hot filament CVD apparatus using the diamond synthesis method of the present invention.

As shown in the figure, this apparatus comprises a vapor phase growth section 30 and a film quality control section 31. The reaction container 22 which is the main part of the vapor phase growth part 30 has a size of 20
It is 0 × 200 mm. In this reaction container 22, flow rate controllers 18 and 18 ′ for feeding the raw material gas into the reaction container 22.
Further, the source gas introduction pipe 4 and a tungsten filament 23 from a power source 24 installed outside are connected. A substrate holder 40 made of stainless steel is installed in the reaction container 22, and a substrate 82 made of silicon of 50 mm square is placed on the holder 40. Further, in the reaction container 22, laser light (633) from the laser oscillator 10 using helium neon installed outside is used.
(nm) 12 can be irradiated onto the substrate 82 via the mirror 11, and scattered light or light emission 14 from the substrate 82 can be observed via the mirror 11 '. Windows 25, 25 'made of aluminum are provided. On the other hand, a film quality control unit 31 for controlling the film quality of the diamond thin film to be synthesized is connected to the vapor phase growth unit 30 centering on the reaction container 22. The film quality control unit is provided with a spectroscope 15 and a photodetector 16 for observing and detecting scattered light or light emission from the substrate 82, and further processing the results obtained by the photodetector 16 to process the diamond thin film. Data processing device 17 for controlling synthesis conditions of
Is installed.

In the synthesis method using the above apparatus, first,
The mixed gas of methane / hydrogen = 1% controlled by the flow rate controllers 18 and 18 'is supplied from the source gas introduction pipe 4 at 100 sccc.
m flow and the pressure was set to 30 torr. The tungsten filament 23 is heated to about 2000 ° C. and the substrate temperature is set to about 8
It was set to 00 ° C. As a result, a diamond thin film is synthesized on the base 82.

At this time, as in Example 1, 1320 cm ^-1
While monitoring the Raman peak of diamond, the filament temperature and the raw material gas ratio were adjusted to maximize the peak intensity, and film formation was continued for 4 hours. In this case, generally, the higher the filament temperature is, the better the crystallinity of diamond can be synthesized, but there is a problem that the substrate temperature rises, and thus the optimum value still exists. As described above, with respect to the gas ratio, the crystallinity is improved when the methane concentration is decreased, but in that case, the film formation temperature is significantly lowered. Here, the film was adjusted so that the filament temperature was maximized with a film having good crystallinity. As a result, it was confirmed that a diamond film having good crystallinity can be stably synthesized by using the method according to the present invention even in the hot filament method. Comparative Example 1 Diamond having good crystallinity was synthesized using a conventionally used microwave plasma CVD apparatus. The conditions were the initial conditions of Example 1, and the procedure was the same as in Example 1. The conditions were as follows: the raw material gas was methane / hydrogen = 1%, the flow rate was 100 sccm, the pressure was 30 Torr, the microwave power was 200 W, the substrate temperature was about 800 ° C., and the film was formed for 4 hours.

An SEM photograph of the grown film is shown in FIG. From this, it can be understood that a diamond thin film with deteriorated crystallinity may be synthesized when the film is formed without the method of the present invention. COMPARATIVE EXAMPLE 2 A method for synthesizing a diamond homoepitaxial film is disclosed in Japanese Patent Laid-Open No. Hei 2
It is disclosed in the publication No. 233591, and it is said that it is synthesized with methane / hydrogen = 6%. A homoepitaxial diamond was synthesized using a conventional microwave plasma CVD apparatus. The conditions were the initial conditions of Example 2, and the procedure was the same as in Example 2. The conditions are as follows: source gas is methane / hydrogen = 2%, flow rate is 100 scm, pressure is 30 Torr,
The microwave power was 200 W, the substrate temperature was about 800 ° C., and the film was formed for 4 hours.

The RHEED pattern of the grown film is shown in FIG. From this, it is understood that a good homoepitaxial diamond film may not be synthesized when the film is formed without the method of the present invention.

[0044]

According to the present invention, it is possible to synthesize while measuring scattered / emitted light or transmitted light due to the diamond thin film, and it is possible to control the film forming conditions without interrupting the synthesis. For this reason, a diamond film having a desired film quality can be easily and stably synthesized, which has a great effect on the practical use of synthetic diamond.

[Brief description of drawings]

FIG. 1 is a microwave plasma C using a diamond synthesis method according to a first specific configuration of the present invention and Example 1.
It is a conceptual diagram of a VD device.

FIG. 2 is an SEM photograph of a diamond thin film formed by a microwave plasma CVD apparatus using a diamond synthesis method according to Example 1 of the present invention.

FIG. 3 is a microwave plasma C using the diamond synthesis method according to the second specific embodiment of the present invention and the second embodiment.
It is a conceptual diagram of a VD device.

FIG. 4 is a RHEED pattern of a homoepitaxial diamond thin film by a microwave plasma CVD apparatus using a diamond synthesis method according to Example 2 of the present invention.

FIG. 5 is a hot filament CVD according to Example 3 of the present invention.
It is a conceptual diagram of a device.

FIG. 6 is an SEM photograph of diamond synthesized by a conventional microwave plasma CVD apparatus.

FIG. 7: RHE of homoepitaxial diamond thin film synthesized by a conventional microwave plasma CVD apparatus
It is an ED pattern.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Magnetron 2 ... Rectangular waveguide 3 ... Applicator 4 ... Raw material gas introduction pipe 5 ... Quartz reaction tube 6 ... Exhaust port 7 ... Plunger 8, 81, 82 ... Substrate 9 ... Substrate holder 10 ... Laser oscillator 11 , 11 '... Mirror 12 ... Laser light 13, 13' ... Aperture 14 ... Scattered light or light emission 15 ... Spectroscope 16 ... Photodetector 17 ... Data processing device 18, 18 '... Flow rate controller 19 ... Light introduction window 20 ... Hollow substrate holder 21 ... Optical fiber 22 ... Reaction vessel 23 ... Filament 24 ... Power supply

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[Procedure amendment]

[Submission date] October 29, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Brief explanation of the drawing

[Correction method] Change

[Correction content]

[Brief description of drawings]

FIG. 1 is a microwave plasma C using a diamond synthesis method according to a first specific configuration of the present invention and Example 1.
It is a conceptual diagram of a VD device.

FIG. 2 is an SEM photograph of a diamond thin film formed by a microwave plasma CVD apparatus using a diamond synthesis method according to Example 1 of the present invention.

FIG. 3 is a microwave plasma C using the diamond synthesis method according to the second specific embodiment of the present invention and the second embodiment.
It is a conceptual diagram of a VD device.

FIG. 4 is a RHEED pattern of a homoepitaxial diamond thin film by a microwave plasma CVD apparatus using a diamond synthesis method according to Example 2 of the present invention.

FIG. 5 is a hot filament CVD according to Example 3 of the present invention.
It is a conceptual diagram of a device.

FIG. 6 is an SEM photograph of a diamond thin film synthesized by a conventional microwave plasma CVD apparatus.

FIG. 7: RHE of homoepitaxial diamond thin film synthesized by a conventional microwave plasma CVD apparatus
It is an ED pattern.

[Explanation of reference numerals] 1 ... Magnetron 2 ... Rectangular waveguide 3 ... Applicator 4 ... Raw material gas introduction pipe 5 ... Quartz reaction tube 6 ... Exhaust port 7 ... Plunger 8, 81, 82 ... Substrate 9 ... Substrate holder 10 ... laser oscillator 11, 11 '... mirror 12 ... laser light 13,13' ... aperture 14 ... scattered light or light emission 15 ... spectrometer 16 ... photodetector 17 ... data processing device 18,18 '... flow rate controller 19 ... Light introduction window 20 ... Hollow substrate holder 21 ... Optical fiber 22 ... Reaction vessel 23 ... Filament 24 ... Power supply

Claims (4)

[Claims] 1. When synthesizing a diamond thin film on a substrate by a vapor phase growth method, the diamond thin film is irradiated with light,
A diamond synthesizing method, which comprises synthesizing light while detecting light from the diamond thin film and controlling film forming conditions. 2. The diamond synthesizing method according to claim 1, wherein the light from said diamond thin film is scattered light, emitted light, or absorbed light. 3. A vapor phase reaction means for synthesizing a diamond thin film by a vapor phase growth method, and a film quality control means for irradiating the diamond thin film with light to control film forming conditions, the vapor phase reaction means comprising: There is at least one opening through which light for irradiating the diamond thin film is transmitted, the film quality control means, a light source for light for irradiating the diamond thin film, a light detection unit for observing light from the diamond thin film, and the light. A diamond synthesizing device, comprising: a data processing device for processing the result obtained by the detection part and transmitting the result to the gas phase reaction means. 4. The diamond synthesizing apparatus according to claim 3, wherein the light from the diamond thin film is scattered light, emitted light, or absorbed light.