JP4535956B2 - Method for producing highly oriented diamond film - Google Patents

Description

  The present invention relates to a highly oriented diamond film in which crystal grains are highly oriented and a method for producing the same, and more particularly to a method for producing a highly oriented diamond film suitable for use in electronic devices such as transistors and diodes.

  Diamond has (a) the highest thermal conductivity at room temperature in materials, (b) a wide band gap of 5.5 eV, (c) a high electron and hole mobility and saturation rate, and (d) dielectric breakdown. Compared to other semiconductor materials such as high electric field, (e) low dielectric constant and dielectric loss, (f) high heat resistance, and (g) low radiation loss, the characteristics required for electronic devices are remarkably high. Is excellent. Therefore, diamond is expected to be applied to ultra-high performance environment-resistant electronic devices and high-frequency devices.

  In order to apply diamond to such a field, a diamond film having a flat surface, a low defect density, and a large area is required. Such a diamond film is composed of single crystal diamond. It is desirable. However, the area of the currently produced single crystal diamond film is about several mm square, and there are many technical problems in order to realize further area expansion.

  Thus, recently, highly oriented diamond films have been studied as an alternative to single crystal diamond films. FIG. 3 is a SEM (Scanning Electron Microscope) photograph of the surface of the highly oriented diamond film. Highly oriented diamond films are broadly categorized as polycrystalline films, but as shown in FIG. 3, all of the square diamond (100) crystal planes face substantially the same direction, The inclination with respect to the film surface is about 5 ° or less, and the film surface is relatively flat. As described above, since the orientation of crystal grains is substantially uniform, the highly oriented diamond film is characterized in that there are few scattering and trapping of carriers (electrons and holes) between the grains and the electrical characteristics are excellent. . It is also known that a highly oriented diamond film has a lower crystal defect density near the surface than a normal polycrystalline film, and the carrier mobility near the surface is about two orders of magnitude higher than that of a polycrystalline film. Yes.

  Conventionally, methods for forming such highly oriented diamond films have been proposed (see, for example, Patent Documents 1 to 3). In Patent Document 1, a single crystal silicon substrate surface is pretreated by exposure to a carbon-containing plasma, and a bias is applied to the pretreated surface while monitoring the completion of nucleation on the substrate surface. A method of forming an oriented diamond film is disclosed in which crystal diamond is deposited on a surface nucleated from a carbon-containing plasma after nucleation of the substrate surface for crystal growth.

  Further, in Patent Document 2, a hydrogen diluted hydrocarbon of 0.1 to 10% by volume is used as a source gas, a gas pressure is 0.13 to 6.6 kPa (1 to 50 Torr), and a substrate temperature is 500. A method for forming a highly oriented diamond thin film is disclosed in which a DC voltage of −100 to −350 V is applied to a substrate for 20 to 240 minutes while the temperature is set to 1100 ° C.

  Furthermore, the method for producing a highly oriented diamond film described in Patent Document 3 includes a highly oriented diamond film synthesizing process under at least two (001) plane selection conditions, and the first stage diamond film synthesizing process is performed. The film speed is set to 1/10 or less of the film formation speed in the second stage diamond film synthesis process performed thereafter. Patent Document 3 discloses that after the synthesis process of all highly oriented diamond films is completed, the highly oriented diamond film obtained by the first stage of highly oriented diamond film synthesis process is removed by polishing. Has been.

Japanese Patent No. 3194820 Japanese Patent No. 3124422 JP 2004-299997 A

  However, the conventional techniques described above have the following problems. The surface of the conventional highly oriented diamond film shown in FIG. 3 has a step of about 0.5 μm between each particle, and there may be a groove of about 1 μm depth between each particle. Therefore, as described in Patent Document 3, in the conventional method for forming a highly oriented diamond film, the obtained diamond film is several μm to several tens of micrometers from the surface in order to further planarize the surface. Only about μm is removed by polishing. FIG. 4 is an SEM photograph of the surface of the highly oriented diamond film after the polishing treatment. As shown in FIG. 4, on the surface of the highly oriented diamond film after the polishing treatment, deep grooves existing between the particles and shallow grooves existing at the boundary between adjacent particles remain without being removed. It is also known that when the polishing process is performed, many defects at the atomic level are generated on the surface of the highly oriented diamond film.

  When the surface of the highly oriented diamond film has macro defects as shown in FIG. 4, surface defects caused by the polishing process, and micro defects at the atomic level, the surface has irregularities. There is a problem that precise microfabrication cannot be performed when forming a device. Further, when a diamond layer is further laminated on the highly oriented diamond film, the atomic level defects on the surface of the underlying highly oriented diamond film are inherited, and the laminated diamond layer also has atomic level defects. There is also a problem that occurs. For this reason, in the conventional electronic device using a highly oriented diamond film, sufficient characteristics are not obtained.

  The present invention has been made in view of such problems, and provides a method for producing a highly oriented diamond film from which a high quality highly oriented diamond film having a flat surface and few surface defects can be obtained. Objective.

The method for producing a diamond film according to the present invention includes a step of synthesizing a highly oriented diamond film, a step of polishing the surface of the highly oriented diamond film, and the surface-polished highly oriented diamond film, while applying a negative bias voltage, and facilities microwave plasma treatment in a gas containing the diluted carbon atoms with hydrogen gas, and the diamond is vapor-deposited surface defect caused by irregularities and polishing by the polishing scratches the And a bias application growth treatment step of flattening the surface of the highly oriented diamond film .

  In the present invention, the highly oriented diamond film whose surface is polished is subjected to microwave plasma treatment in a gas containing carbon atoms diluted with hydrogen gas while applying a negative bias voltage. The surface of the highly oriented diamond film can be flattened, and the density of surface defects caused by polishing can be reduced.

  This method for producing a highly oriented diamond film is performed in hydrogen gas or hydrogen without applying a negative bias voltage to the surface-polished highly oriented diamond film before the bias application growth treatment step. A negative bias voltage is applied to the first plasma treatment step in which microwave plasma treatment is performed in a gas containing carbon atoms diluted with a gas and / or the highly oriented diamond film after the bias application growth treatment step. A second plasma treatment process may be performed in which microwave plasma treatment is performed in hydrogen gas or in a gas containing carbon atoms diluted with hydrogen gas, without applying. As a result, the surface of the highly oriented diamond film can be further planarized, and the density of surface defects generated by polishing can be greatly reduced.

The gas containing carbon atoms diluted with hydrogen gas used in the bias application growth treatment step has a ratio (C / H) of the amount of carbon atoms (mol) to the amount of hydrogen atoms (mol) (C / H) of 100 to 100. It can be 260000 ppm. Thus, the planarizing the surface of efficiently highly-oriented diamond film, it is possible to reduce the density of surface defects.

In the bias application growth treatment step, the gas pressure of the gas containing carbon atoms diluted with the hydrogen gas may be 1333 to 16000 Pa. Thus, the planarizing the surface of efficiently highly-oriented diamond film, it is possible to reduce the density of surface defects.

  Furthermore, the gas containing carbon atoms diluted with hydrogen gas is, for example, methane gas diluted with hydrogen gas. In that case, the concentration of the methane gas is preferably 0.5% by volume or less, more preferably. Has a methane gas concentration of 0.1% by volume or less.

On the other hand, the negative bias voltage can be set to, for example, −300 to −100V. Thus, the planarizing the surface of efficiently highly-oriented diamond film, it is possible to reduce the density of surface defects.

Further, the microwave plasma processing time in the bias application growth processing step may be 5 to 60 minutes. Thus, the planarizing the surface of efficiently highly-oriented diamond film, it is possible to reduce the density of surface defects.

  According to the present invention, a highly oriented diamond film whose surface is polished is subjected to microwave plasma treatment in a gas containing carbon atoms diluted with hydrogen gas while applying a negative bias voltage. It is possible to obtain a high-quality highly oriented diamond film that is flat and has few surface defects.

  Hereinafter, embodiments of the present invention will be specifically described with reference to the accompanying drawings. First, the highly oriented diamond film of the first embodiment of the present invention will be described. The highly oriented diamond film of the present embodiment is obtained by polishing the surface of the highly oriented diamond film formed by a well-known method and then applying a negative bias voltage to the surface oriented high oriented diamond film. And Bias Enhanced Growth (BEG) treatment in which microwave plasma treatment is performed in a gas containing carbon atoms diluted with hydrogen gas. FIG. 1 is a SEM photograph showing the surface of the highly oriented diamond film of the present embodiment. FIG. 1 shows a region where deep grooves remain between crystal grains. As shown in FIG. 1, the highly oriented diamond film of this embodiment has a flat surface and a lower density of surface defects than the highly oriented diamond film after the polishing treatment shown in FIG. .

  In the highly oriented diamond film of this embodiment, the surface-polished highly oriented diamond film is subjected to a bias applied growth treatment, so that the surface can be flattened compared to the conventional highly oriented diamond film. At the same time, surface defects can be reduced. As a result, excellent characteristics can be obtained even when applied to electronic device applications.

  Next, as a second embodiment of the present invention, a method for producing a highly oriented diamond film according to the first embodiment will be described. The inventors of the present invention have carried out a plasma treatment on a highly-oriented diamond film whose surface has been polished in a gas containing carbon atoms diluted with hydrogen gas while applying a negative bias voltage, so that irregularities and polishing by a polishing rod can be achieved. It has been found that diamond is deposited on the surface defect caused by the above, the surface of the film is flattened, and the density of surface defects is reduced.

  Therefore, in the method for producing a highly oriented diamond film according to the present embodiment, first, for example, diamond abrasive grains are dispersed in cast iron having a smooth surface, and the diamond film is pressed against this to polish the diamond film. The surface of the formed highly oriented diamond film is polished. Next, microwave plasma treatment (bias applied growth treatment) is performed on the surface-polished highly oriented diamond in a gas containing carbon atoms diluted with hydrogen gas while applying a negative bias voltage. .

  The biased growth process for the highly oriented diamond film that has been subjected to the polishing process can be performed by, for example, an inorganic material type microwave plasma CVD (Chemical Vapor Deposition) apparatus. FIG. 2 is a schematic diagram of a microwave plasma CVD apparatus used for BEG processing. As shown in FIG. 2, in the microwave plasma CVD apparatus used in the present embodiment, a substrate support 10 supported by a support bar 9 is disposed in a chamber 6 with its surface horizontal. A substrate 11 is placed on the substrate support 10, and the vertical position of the substrate 11 is adjusted by the vertical movement of the support bar 9.

  And outside the chamber 6 in the vicinity of the substrate 11, a microwave waveguide 4 for irradiating microwaves is installed with its longitudinal direction horizontal. At one end of the waveguide 4, a microwave power source 1, an isolator 2 that prevents a reflected wave of the microwave oscillated from the microwave power source 1 from entering the microwave power source 1, and this reflection A tuner 3 for adjusting the wave to be minimized is installed. In addition, a plunger 5 that adjusts the resonance position of the microwave or adjusts the generation position of the plasma 13 is disposed at the other end of the waveguide 4.

  Furthermore, a processing gas introduction port 7 is provided at the upper end of the chamber 6, and an exhaust port 8 connected to a vacuum pump is provided at the lower end thereof. Thus, the inside of the chamber 6 is evacuated through the exhaust port 8 and the processing gas is supplied into the chamber 6 through the introduction port 7. Further, in the vicinity of the substrate holder 10 in the chamber 6, an electrode 12 on a flat plate is disposed so as to face the substrate 11 on the substrate holder 10. The substrate holder 10 and the counter electrode 12 are connected to an external AC power supply 14, whereby an AC voltage is applied between the substrate 11 and the electrode 12.

  In the method for producing a highly oriented diamond film of the present embodiment, the composition of a gas containing carbon atoms diluted with hydrogen gas (hereinafter also referred to as BEG processing gas) used for bias applied growth treatment is carbon. The ratio (C / H) between the amount of atoms (mole) and the amount of hydrogen atoms (C / H) is preferably 100 to 260000 ppm. When a gas having C / H of less than 100 ppm is used, the surface of the diamond film may be significantly etched by hydrogen plasma, and a flat surface may not be obtained. On the other hand, when a gas with C / H exceeding 260000 ppm is used, diamond is synthesized again on the polished surface, and each diamond crystal particle constituting the highly oriented diamond film grows unevenly, resulting in unevenness on the surface. The surface state before polishing may return. The C / H range in the atomic composition of the BEG processing gas is wide because the optimum conditions for flattening the highly oriented diamond film are processing conditions other than the gas composition such as plasma processing time and substrate temperature. It is because it is strongly influenced by.

  Further, the ratio (C / H) between the amount (mole) of carbon atoms and the amount of hydrogen atoms (mole) in the BEG processing gas is more preferably 100 to 2000 ppm. However, the optimum gas composition in the bias application growth process strongly depends on various processing conditions such as the plasma processing time, the substrate temperature, the gas pressure, and the structure of the film forming apparatus, as described above. The preferred range is merely a guide.

As the BEG processing gas having such an atomic composition, for example, hydrogen (H ₂ ) gas so that the methane (CH ₄ ) gas concentration is 0.5 volume% or less, more preferably 0.1 volume% or less. And those diluted with 1.

  Furthermore, the pressure of the BEG processing gas during the bias application growth processing is preferably 1333 to 16000 Pa. When the pressure of the BEG processing gas is less than 1333 Pa, ion damage due to a bias electric field may occur on the surface of the highly oriented diamond film. On the other hand, when the pressure of the BEG processing gas exceeds 16000 Pa, the effect of the bias electric field may disappear.

  Furthermore, when the BEG processing gas pressure during the bias application growth processing is in the above range, the negative bias voltage applied to the highly oriented diamond film after the polishing processing is desirably −300 to −100V. . When the negative bias voltage is a low bias exceeding −100 V, the bias effect is hardly observed, and the surface of the highly oriented diamond film may be roughened by etching, or unevenness may become remarkable due to uneven growth. Similarly, when the negative bias voltage is a high bias of less than −300 V, the surface of the highly oriented diamond film may be etched and rough, or unevenness may become remarkable due to non-uniform growth. These phenomena may occur even when other conditions such as the plasma processing time, the substrate temperature, and the gas pressure are changed.

  The bias application growth processing time (negative bias application time) is preferably 5 to 60 minutes. When the bias application growth processing time is shorter than 5 minutes, the surface of the highly oriented diamond film may not be sufficiently planarized. On the other hand, when the bias application growth processing time is longer than 60 minutes, diamond is synthesized again on the polished surface, the surface irregularities become large, and the state before polishing may be restored. A more preferable range of the bias application growth processing time is 10 to 30 minutes.

  Furthermore, in the method for producing a highly oriented diamond film of the present embodiment, the surface is polished and then biased growth treatment is performed. Even if the bias application growth treatment is performed according to the method and conditions, physical unevenness cannot be eliminated, and a highly oriented diamond film with a flat surface and few surface defects cannot be obtained. That is, in order to obtain a flat surface state with few defects like the highly oriented diamond film of this embodiment, the polishing treatment is also an important factor.

  In the method for producing a highly oriented diamond film of the present embodiment, the surface-polished diamond film is subjected to microwave plasma in a gas containing carbon atoms diluted with hydrogen gas while applying a negative bias voltage. Since the biased growth process is performed, the surface is flat and the defect density of the surface is low compared to a highly oriented diamond film that has not been subjected to the biased growth process and is simply polished. A highly oriented diamond film is obtained. As a result, the highly oriented diamond film of this embodiment manufactured by this method can obtain excellent characteristics when applied to an electronic device.

  In the manufacturing method of the highly oriented diamond film of the present embodiment, the bias application growth treatment is performed using the inorganic material-type microwave plasma CVD apparatus shown in FIG. There is no limitation as long as microwave plasma treatment can be performed in a gas containing carbon atoms diluted with hydrogen gas while applying a negative bias voltage, and an apparatus other than the microwave plasma CVD apparatus shown in FIG. 2 is used. May be.

  Next, a method for manufacturing a highly oriented diamond film according to the third embodiment of the present invention will be described. In the manufacturing method of the highly oriented diamond film of the second embodiment described above, the biased growth process is performed on the highly oriented diamond film after the polishing process. After that, microwave plasma treatment may be performed in hydrogen gas or a gas containing carbon atoms diluted with hydrogen gas without applying a negative bias voltage. As a result, the surface of the highly oriented diamond film can be further planarized as compared with the method for producing the highly oriented diamond film of the second embodiment described above. For example, when microwave plasma treatment is performed in a gas containing carbon atoms diluted with hydrogen gas, a high-quality diamond layer is laminated on the highly oriented diamond surface, and depending on the synthesis conditions, diamond growth in the in-plane direction may occur. move on.

  In the method for manufacturing a highly oriented diamond film of the present embodiment, when a gas containing carbon atoms diluted with hydrogen gas is used in the microwave plasma processing performed before and / or after the bias application growth processing. Is preferably a composition in which the ratio (C / H) of the amount (mole) of carbon atoms to the amount (mole) of hydrogen atoms is 260000 ppm or less. When a gas with C / H exceeding 260,000 ppm is used, diamond is synthesized again on the polished surface, and each diamond crystal particle constituting the highly oriented diamond film grows unevenly. It may return to the previous surface condition.

  Further, the first plasma processing gas to be implemented before the bias application growth processing has a composition with C / H of 2000 ppm or less, and the BEG processing gas has a composition with C / H of 100 to 260000 ppm. More preferably, the second plasma treatment gas to be implemented after the treatment has a composition in which C / H is 2000 ppm or less. However, as described above, the optimum gas composition in these processes strongly depends on various processing conditions such as the plasma processing time, the substrate temperature, the gas pressure, and the structure of the film forming apparatus. The more preferable range is merely a guideline.

  The configuration and effects other than those described above in the method for producing a highly oriented diamond film of the present embodiment are the same as those of the method for producing a highly oriented diamond film of the second embodiment described above.

  The effects of the embodiments of the present invention will be described below. First, as a first example of the present invention, a highly oriented diamond film was produced by the method for producing a highly oriented diamond film of the second embodiment described above using the microwave plasma CVD apparatus shown in FIG. . In this example, first, a highly oriented diamond film having a thickness of about 45 μm was formed on a low resistance p-type silicon substrate having a length of 1 cm and a width of 1 cm according to the prior art. Next, the surface of this highly oriented diamond film was polished and planarized by about 5 μm. The surface of the diamond film obtained by polishing was similar to the surface of the diamond film shown in FIG. 4, but no deep pits as shown in FIG. 4 were found.

Next, the highly oriented diamond film after the surface polishing was subjected to a bias application growth process using a microwave CVD apparatus shown in FIG. At that time, the wavelength of the microwave is 2.45 GHz, and the BEG processing gas is diluted with H ₂ gas so that the CH ₄ gas concentration becomes 0.075 vol% (C / H = 380 ppm). did. Further, the gas pressure for BEG treatment was 2666 Pa, the temperature of the substrate 11 was 750 to 800 ° C., and a voltage of −150 V was applied between the substrate 11 and the counter electrode 12.

  When the bias application growth treatment was performed for 20 minutes under the above-described conditions, the surface of the highly oriented diamond film could be flattened over the entire surface, similarly to the highly oriented diamond film shown in FIG. Further, the calculated surface roughness Ra of the surface of the highly oriented diamond film before and after the bias application growth treatment was measured by an atomic force microscope (AFM). The results are shown in Table 1 below.

  As shown in Table 1 above, the highly oriented diamond film before and after the bias application growth treatment has a calculated surface roughness Ra of about 1/3 that of the highly oriented diamond film before the treatment. In the region corresponding to the grain boundary, the surface was flattened.

  In addition, the surface of the highly oriented diamond film before and after the bias application growth treatment is subjected to Raman spectrum, XPS (X-ray Photoelectron Spectroscopy), cathode luminescence, TEM (Transmission Electron Microscope) and LEED (Low Energy Electron Diffraction). ) And the change in surface defects was examined. In any measurement, the highly oriented diamond film after the bias applied growth treatment was highly oriented before the treatment according to the measurement of electron diffraction and cathodoluminescence. The surface defects were reduced as compared with the conductive diamond film.

  Next, as a second example of the present invention, a highly oriented diamond film is produced by the method for producing a highly oriented diamond film of the third embodiment described above, using the microwave plasma CVD apparatus shown in FIG. did. In this example, first, a highly oriented diamond film having a thickness of about 45 μm was formed on a low resistance p-type silicon substrate having a length of 1 cm and a width of 1 cm according to the prior art. Next, the surface of this highly oriented diamond film was polished and planarized by about 5 μm. The surface of the diamond film obtained by polishing was similar to the surface of the diamond film shown in FIG. 4, but no deep pits as shown in FIG. 4 were found.

Next, the highly oriented diamond film after surface polishing is diluted with H ₂ gas so that the CH ₄ gas concentration becomes 0.03% by volume using the microwave CVD apparatus shown in FIG. C / H = 150 ppm), and a microwave plasma treatment was performed for 30 minutes without applying a negative bias. During this first plasma treatment, the temperature of the substrate 11 rose from 600 ° C. to 800 ° C. Subsequently, by using the microwave CVD apparatus shown in FIG. 2, a gas diluted with H ₂ gas (C / H = 500 ppm) so that the CH ₄ gas concentration becomes 0.10% by volume is used. A voltage of −150 V was applied between the counter electrode 12 and a bias application growth process was performed for 15 minutes. During this bias application growth process, the temperature of the substrate 11 was approximately 800 ° C. Further, using the microwave CVD apparatus shown in FIG. 2, a gas (C / H = 150 ppm) diluted with H ₂ gas so that the CH ₄ gas concentration becomes 0.03% product% is used, and a negative bias is applied. The microwave plasma treatment was performed for 15 minutes without applying. During this second plasma treatment, the temperature of the substrate 11 was approximately 800 ° C. In any treatment, the wavelength of the microwave was 2.45 GHz, and the gas pressure was 2666 Pa.

  In the highly oriented diamond film of this example, as in the highly oriented diamond film shown in FIG. Further, the calculated surface roughness Ra of the surface of the highly oriented diamond film in each treatment stage was measured by AFM. The results are shown in Table 2 below.

  As shown in Table 2 above, it was confirmed that the surface of the highly oriented diamond film was flattened as the treatment progressed. Specifically, before and after the bias application growth treatment, high orientation that is simply surface-polished by microwave plasma treatment in a gas containing carbon atoms diluted with hydrogen gas without applying a negative bias voltage. As compared with the conductive diamond film, the arithmetic average roughness Ra of the surface could be reduced to about 1/4.

  Further, when the defect density on the surface of the highly oriented diamond film in each processing step was examined by the same method as in the first example, the highly oriented diamond film of this example was subjected only to polishing treatment. Compared with the oriented diamond film, the surface defect density was greatly reduced. This is because mechanical treatment is performed by performing a microwave plasma treatment without applying a negative bias voltage, followed by a bias application growth treatment, and then performing a microwave plasma treatment without applying a negative bias voltage. This shows that the surface defects caused by the above are reduced. Furthermore, using a hydrogen gas instead of a gas containing carbon atoms diluted with a hydrogen gas, a negative bias voltage is applied before and after the bias application growth process under the same conditions as in this example except for that. When the microwave plasma treatment was performed without the same effect, the same effect as in this example was obtained.

It is a drawing substitute photograph (SEM photograph) of the surface of the highly oriented diamond film of the 1st Embodiment of this invention. It is a figure which shows the outline of the microwave plasma CVD apparatus used for BEG processing. It is a drawing substitute photograph of the surface of the conventional highly oriented diamond film (SEM photograph). It is a drawing substitute photograph of the surface of the highly oriented diamond film after the polishing treatment (SEM photograph).

Explanation of symbols

DESCRIPTION OF SYMBOLS 1; Microwave power source 2; Isolator 3; Tuner 4; Waveguide 5; Plunger 6; Chamber 7; Inlet 8; Exhaust port 9; Support rod 10; Substrate support 11; Substrate 12; 14; AC power supply

Claims (9)

A step of synthesizing a highly oriented diamond film, a step of polishing the surface of the highly oriented diamond film, and applying a negative bias voltage to the surface-polished highly oriented diamond film while applying a hydrogen gas in and facilities microwave plasma treatment with a gas containing a diluted carbon atoms, to flatten the surface of the highly oriented diamond film by depositing diamond on the surface defect portion caused by irregularity and polishing by the polishing flaws A method for producing a highly oriented diamond film, comprising: a bias application growth treatment step. In the gas containing carbon atoms diluted in hydrogen gas or hydrogen gas without applying a negative bias voltage to the surface-polished highly-oriented diamond film before the bias application growth treatment step. 2. The method for producing a highly oriented diamond film according to claim 1, further comprising a first plasma processing step of performing a microwave plasma processing. The highly oriented diamond film after the bias application growth treatment step is subjected to microwave plasma treatment in a hydrogen gas or a gas containing carbon atoms diluted with a hydrogen gas without applying a negative bias voltage. The method for producing a highly oriented diamond film according to claim 1, further comprising a second plasma treatment step. The gas containing carbon atoms diluted with hydrogen gas used in the bias application growth process step has a ratio (C / H) of the amount (mol) of carbon atoms to the amount (mol) of hydrogen atoms of 100 to 260000 ppm. The method for producing a highly oriented diamond film according to any one of claims 1 to 3, wherein: 5. The high orientation property according to claim 1, wherein in the bias application growth treatment step, a gas pressure of the gas containing carbon atoms diluted with the hydrogen gas is set to 1333 to 16000 Pa. 6. Diamond film manufacturing method. 6. The gas containing carbon atoms diluted with hydrogen gas is obtained by diluting methane gas with hydrogen gas, and the concentration of the methane gas is 0.5% by volume or less. 2. A method for producing a highly oriented diamond film according to claim 1. The method for producing a highly oriented diamond film according to claim 6, wherein the methane gas concentration is 0.1% by volume or less. The method for producing a highly oriented diamond film according to claim 1, wherein the negative bias voltage is −300 to −100V. 9. The method for producing a highly oriented diamond film according to claim 1, wherein the microwave plasma treatment is performed for 5 to 60 minutes in the bias application growth treatment step.

Images