JP2002173394A - Method of producing diamond, plasma apparatus and method of producing diamond using the plasma apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of producing diamond, by which it is possible to efficiently allow reaction products to reach floating diamond particles and a plasma generator. SOLUTION: The diamond particles 11 are allowed to float in a reaction tube 1 by sending a gaseous raw material into the reaction tube 1. The reaction products are formed by applying an electric field to the gaseous raw material using an induction coil 2, and the reaction products react with the diamond particles 11, thereby diamond is produced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a diamond production method for producing diamond using particulate diamond as a nucleus by a gas phase synthesis method, and a plasma apparatus.

[0002]

2. Description of the Related Art Diamond has a large band gap (5.5 eV) and a large carrier mobility (electron: 180).
0 cm ² / V · S, holes: 1600 cm ² / V · S) and high thermal conductivity (20 W / cm · K), and can be obtained with other materials such as high hardness and excellent wear resistance. Not having various characteristics. For this reason, recently, the synthesis of diamond from the gas phase, especially the chemical vapor deposition (hereinafter referred to as CVD)
Research on a method for producing diamond using the method has been frequently performed.

FIG. 6 is a schematic diagram of a plasma apparatus in a conventional diamond manufacturing method.

A conventional method for producing diamond by the CVD method is disclosed in Japanese Patent Application Laid-Open No. 1-157497, and FIG. 6 shows a plasma apparatus used in the production method.

[0005] An induction coil 32 is provided on the outer periphery above the reaction tube 31.
And a high frequency power supply 33 for supplying power to the induction coil 32 is connected.

On the upper surface of the reaction tube 31, a source gas supply device 34 for supplying a source gas of diamond and a plasma gas supply device 3 for supplying a carrier gas for generating plasma are provided.
5 are provided.

At the bottom of the reaction tube 31, a gas supply device 37 for supplying diamond particles 36 and for supplying a gas for suspending the diamond particles 36 is provided.
Is provided.

In addition, the inclined surface of the bottom in the reaction tube 31 has
Two vibrating plates 38 for promoting the floating of the diamond particles 36 are provided. An electromagnet 39 for vibrating the vibration plate 38 is provided outside the reaction tube 31, and an electromagnet power supply 40 for supplying power to the electromagnet 39 is connected to the electromagnet 39.

An exhaust device 41 for exhausting gas in the reaction tube 31 is provided on a side surface of the reaction tube 31.

Next, a conventional method for producing diamond will be described with reference to FIG.

First, the gas in the reaction tube 31 is evacuated by the exhaust device 41 to make it vacuum. In addition, the diamond particles 36 and a gas for suspending the diamond particles 36 are supplied into the reaction tube 31 by the particle suspension gas supply device 37, and the diamond particles 36 float by the flow pressure of the gas. At this time, the suspension of the diamond particles 36 is supplemented by vibrating the diaphragm 38 by the electromagnet 39.

Next, a carrier gas for exciting plasma is supplied through a plasma gas supply device 35, and a raw material gas is supplied through a source gas supply device 34 into a reaction tube 3.
1 from the top. Then, electric power is supplied to the induction coil 32 by the high frequency power supply 33 to generate an electric field in the reaction tube 31. And the generated electric field decomposes the source gas,
By using a reaction product, the reaction product grows around the diamond particles 36 as a nucleus and can precipitate diamond.

[0013]

However, in the conventional plasma apparatus for producing diamond, a raw material gas is supplied from above the reaction tube 31 and a floating gas for floating the diamond is supplied from below the reaction tube 31. For this reason, the exhaust device 41 had to be provided near the center of the side surface of the reaction tube 31. Further, an electromagnet for vibrating the vibration plate 38 is provided on a lower surface of the reaction tube 31. Therefore,
The induction coil 32 for generating plasma had to be provided above the same reaction tube 31 as the plasma gas supply device 35.

As a result, the region where the reaction product generated by decomposition of the raw material gas is present is not in close contact with the region where the floating diamond particles 36 are present. There is a problem that the reaction efficiency of the raw material gas is low because the reaction product that has hit the wall surface or the decomposed reaction product is polymerized into amorphous carbon before reaching the surface.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for producing diamond and a plasma apparatus capable of efficiently causing a reaction product to reach floating diamond particles in order to solve the above-mentioned problems.

[0016]

According to the method for producing diamond of the present invention, diamond particles are floated in the housing by feeding the raw material gas into the housing, and the source gas is applied by applying an electric field to the raw material gas. It is characterized by decomposing into a reaction product, and reacting the diamond particles with the reaction product.

As a result, the source gas is decomposed by the generated electric field to become a reaction product, and the floating diamond particles react with the reaction product, whereby the diamond crystal can be grown at a high speed. In addition, the generated reaction product immediately reacts with the diamond particles in the region where the electric field is generated, so that the utilization efficiency of the source gas can be increased.

Further, the plasma device according to the present invention is a plasma device having an electric field generating means, a gas inlet and a gas outlet provided in a housing, wherein the gas inlet is provided on a bottom surface of the housing. In addition, the side surface of the housing is formed in a step shape, and the electric field generating means is provided at each step portion.

Further, the plasma device of the present invention is a plasma device having an electric field generating means, a gas inlet and a gas outlet provided in a housing, wherein the gas inlet is provided on a bottom surface of the housing. In addition, the electric field generating means is composed of a plurality of electrode pairs having a pair of two electrodes provided inside the housing, and is provided such that an electrode interval between each of the electrode pairs decreases toward a gas inlet. It is characterized by having.

Thus, since the diamond particles are located in the housing according to the mass of the particles according to the particle diameter, an electric field can be generated by the electric field generating means provided for each stepped portion or by each of a plurality of electrode pairs. Thus, it is possible to produce diamond by applying an electric field only to a place where diamond particles having a desired particle size exist in the housing.

According to the plasma apparatus of the present invention, there is provided a plasma apparatus having an electric field generating means, a gas inlet and a gas outlet provided in a housing, wherein the gas inlet is provided on a side surface of the housing. In addition, the electric field generating means comprises electrodes provided on the upper and lower sides of the housing.

By adjusting the distance between the upper and lower electrodes with high frequency, the diamond particles are prevented from falling due to the mass of the diamond particles when the diamond particles are thrown into the housing and floated. Can be suspended.

[0023]

Embodiments of the present invention will be described below in detail with reference to the drawings.

(First Embodiment) FIG. 1 is a schematic view of a plasma apparatus used in a method for producing diamond according to a first embodiment of the present invention. In the first embodiment, diamond is manufactured using an inductively coupled CVD method.

As shown in FIG. 1, an induction coil 2 serving as an electric field generating means is provided around a quartz reaction tube 1 used as a housing.
Is provided. A matching box 9 and a power supply 10 are connected to the induction coil 2. By supplying power from the power supply 10, an electric field can be generated in the reaction tube 1 using the induction coil 2.

On the lower surface of the reaction tube 1, there is provided a gas supply tube 3 through which a diamond raw material and a gas for plasma excitation flow from a gas inlet. On the upper surface of the reaction tube 1, three gas exhaust tubes 4 having gas exhaust ports for exhausting gas in the reaction tube 1 are provided.

The amount of gas to be supplied is adjusted by a gas inflow adjusting valve 6 provided in the gas supply pipe 3.
The amount of gas to be exhausted is adjusted by a gas exhaust amount adjusting valve 7 provided in each gas exhaust pipe 4. Further, gas is exhausted by an exhaust device 8 connected to the gas exhaust pipe 4.

The reaction tube 1 provided with the gas supply tube 3
Is formed in a conical shape convex toward the outside of the reaction tube 1.

Further, an inclined portion 5 is formed on the bottom surface of the reaction tube 1. Here, when the angle of the inclined portion 5 is close to 0 degrees, a portion (gas pool) where the gas supplied into the reaction tube 1 is difficult to flow is generated near the boundary between the bottom surface and the side surface of the reaction tube 1. However, as the inclination of the inclined portion 5 becomes steeper, the gas being supplied is supplied near the boundary between the bottom surface and the side surface of the reaction tube 1, and the gas is supplied to the entire reaction tube 1. become. In addition to the conical shape, the bottom surface of the reaction tube 1 is formed in a convex shape such as a quadrangular pyramid according to the shape of the reaction tube, and has a sloped portion. Any shape that does not need to be used.

Next, a method for producing diamond using the plasma apparatus of FIG. 1 will be described.

First, the gas in the reaction tube 1 is evacuated to an exhaust device 8 in advance.
The air is sufficiently exhausted to 1 × 10 ⁻⁴ Pa using the gas.

Next, a diamond source gas and a carrier gas of argon for facilitating the excitation of plasma are used as the inflowing gas, and the diamond particles 11 having a particle diameter of 30 μm are passed through the gas supply pipe 3 together with the inflowing gas. It flows into the reaction tube 1.

Then, the gas exhaust amount is adjusted by the gas exhaust amount control valve 7 so that the diamond particles 11 are in a floating state in a region where an electric field is generated, and the pressure is set to 8.0 Pa.
Here, the atmospheric pressure may be adjusted according to the particle size of the diamond, and the particle size of the diamond particles 11 is 0.1 μm to 100 μm.
In the case of μm, the pressure is appropriately adjusted selectively within the range of 1000 Pa to 0.01 Pa. When different diamond particles are present, an appropriate pressure is appropriately selected.

The diamond raw material gas in the first embodiment has a mixing ratio of hydrogen and methane of 5: 100 and a flow rate of the mixed gas of 0.05 l / min. Here, the hydrogen gas has an effect of etching the non-diamond structure, and it is better to mix at least 20 times or more the methane gas.

Examples of other source gases include ethane, acetylene, butane, etc., and methane is preferred as an inexpensive and volatile hydrocarbon gas. Also,
In order to easily excite plasma, helium or a carrier gas using helium and argon in combination may be used.

The gas inflow of the source gas and the carrier gas is adjusted by using the gas inflow adjusting valve 6. In addition,
In addition to flowing the diamond particles 11 simultaneously with the gas, the diamond particles 11 may be placed in the reaction tube 1 in advance, or may be appropriately placed after the raw material gas and the carrier gas have flowed.

Next, a microwave of 2.45 GHz is used for 60
0 W power is input to the power supply 10 and the matching box 9
The electric power is adjusted and output to the induction coil 2 to generate an electric field in the reaction tube 1 to bring the carrier gas into a plasma state.

With the carrier gas converted into plasma,
Feed gas methane (CH ₄₎ also becomes a plasma state, a number of hydrocarbon compounds _{(CH 3, CH 2, CH} , CH 3 -
) Are produced. The reaction product is the diamond particles 1 in a floating state in the reaction tube 1.
Diamond can be manufactured by growing diamond particles 11 with 1 as a nucleus. At this time,
By adjusting the gas flow rate of the raw material gas, the diamond particles 11 can be present in the region where the electric field is generated, so that the reaction product generated by decomposition of the raw material gas and the diamond particles 11 immediately react, The source gas can be used efficiently.

Although the temperature of the diamond particles 11 rises due to the heat generated by the gasification of the gas, the diamond particles 11 are further heated by using a heating device 12 provided at a predetermined position outside the reaction tube 1 by light radiation or the like. Is heated to 800 degrees in the reaction tube 1 to promote the growth of the diamond particles 11. This is the same for the following embodiments.

Further, in the first embodiment, since the gas flows appropriately along the inclined portion 5 by forming the inclined portion 5 on the bottom surface of the reaction tube 1, the diamond particles 11 cause the diamond particles 11 to move by gravity to the bottom surface of the reaction tube 1. When the diamond particles 11 come to the gas inlet, the diamond particles 11 will float again, and the diamond particles 11
Can be used without waste.

Incidentally, a plurality of gas supply pipes 3 may be provided on the bottom surface of the reaction tube 1 in order to easily control the floating state of the diamond particles 11. At this time, a main gas supply pipe and a plurality of auxiliary gas supply pipes are appropriately provided in the reaction tube 1 and a desired amount of diamond particles can be brought into a floating state by finely adjusting the gas amount of the auxiliary gas supply pipe. This is the second and third
The same applies to the embodiment.

Although three gas exhaust pipes 4 are provided in the present embodiment, one gas exhaust pipe may be provided. However, by providing a plurality of gas exhaust pipes 4, the gas exhausted from the reaction pipe 1 can be reduced. Because it is dispersed and exhausted by multiple gas exhaust units,
The gas flow rate from the bottom surface to the top surface of the reaction tube 1 can be changed.

(Second Embodiment) FIG. 2 is a schematic view of a plasma apparatus used in a diamond manufacturing method according to a second embodiment of the present invention. In the second embodiment, diamond is manufactured using an inductively coupled CVD method.

As shown in FIG. 2, the difference between the plasma device used in the second embodiment and the plasma device used in the first embodiment is that the side surface of the reaction tube 1 is formed in a step shape and a plurality of steps are formed. This is the point where the unit 13 is provided. Step 13
Is provided so as to become narrower toward the gas inlet side of the gas supply pipe 4. Further, around the step 13,
An induction coil 27 is wound around each step 13. Each induction coil 27 is connected to a switch 28.

In order to make the gas flow uniform, the reaction tube 1
Has a circular cross-section when cut perpendicular to the plane of the drawing at the opposing step 13. Further, the components denoted by the same reference numerals as those of the plasma device shown in FIG.

The method for producing diamond is the same as in the first embodiment.

As shown in FIG. 2, a step 13 is provided stepwise on the side surface of the reaction tube 1 in a convex shape toward the gas supply tube 4 so that the diamond particles 11 float at a relatively small gas flow rate. It is possible to do.

Here, the gas flow rate is usually large below the reaction tube 1 and small above the reaction tube 1.
On the side, that is, on the lower side, those having a small particle diameter of the diamond particles 11 and having a small mass float on the gas exhaust pipe 4 side, that is, on the upper side. Change. The larger the particle size, the lower the diamond particles 11 are located due to their own weight.

When the diamond particles 11 grow in crystal and have a large particle diameter, the diamond particles 11 are sequentially positioned downward by their own weight. Then, the diamond particles 11 in the reaction tube 1 located in the lateral direction of the step portion 13 are located according to the particle diameter of the particles.

Therefore, by supplying electric power to the induction coil 27 provided for each step portion 13 using the switch 28, the diamond particles 11 having a specific particle diameter can be selectively provided.
An electric field can be applied to the region where the surface exists.

Thus, for example, when a diamond having a large particle diameter is desired, an electric field is generated only in a region where the diamond particles 11 having a small particle diameter floating upward exist, and diamond can be crystal-grown. Thus, a relatively uniform diamond can be produced.

(Third Embodiment) FIG. 3 is a schematic view of a plasma apparatus used in a diamond manufacturing method according to a third embodiment of the present invention. In the third embodiment, diamond is manufactured using a parallel plate electrode type CVD method.

As shown in FIG. 3, the plasma device used in the third embodiment uses a parallel plate electrode 14a on the inner side surface of the reaction tube 1, instead of the induction coil in the first embodiment, as an electric field generating means. 14b is provided to generate an electric field. Otherwise, the plasma apparatus is the same as the plasma apparatus of the first embodiment, and the description of the same reference numerals is omitted.

The method for producing diamond is the same as in the first embodiment.

As in the third embodiment, the parallel plate electrode 14 is used.
When an electric field is generated using a and 14b,
The electric field strength is lower than when an induction coil is used.

However, the generation of high-frequency plasma between the parallel plate electrodes 14a and 14b causes the negatively charged diamond particles 11 to macroscopically reduce the parallel plate electrode 1a.
Without reciprocating between 4a and 14b, they gather near the center between the parallel plate electrodes 14a and 14b to supplement the floating state of the diamond particles 11. At this time, near the center between the parallel plate electrodes 14a and 14b, the electric field intensity is high and a large amount of reaction products are present, so that the diamond production speed is increased and the diamond production is promoted. The negative charge of the diamond particles 11 is
It can also be performed by applying an electric field to the diamond particles 11 in advance.

Further, by increasing the frequency applied to the parallel plate electrodes 14a and 14b, the diamond particles 11 can be gathered near the center between the parallel plate electrodes 14a and 14b.

(Fourth Embodiment) FIG. 4 is a schematic diagram of a plasma apparatus used in a diamond manufacturing method according to a fourth embodiment of the present invention. In the fourth embodiment, diamond is manufactured using a parallel plate electrode type CVD method.

As shown in FIG. 4, in the plasma device used in the fourth embodiment, a pair of parallel plate electrodes 15a and 15b are arranged on the inner side surface of the reaction tube 1 so as to face each other as electric field generating means. And a plurality of the electrode pairs are provided. Further, the electrode pairs are provided such that the electrode intervals of each electrode pair are narrowed toward the gas supply pipe 3 on the bottom surface of the reaction tube 1 at a constant interval. And
The electrode pair generates an electric field in the reaction tube 1. Except that the electrode pairs of the parallel plate electrodes 15a and 15b are provided and that each of the electrode pairs is connected to the switch 29, the plasma apparatus of the third embodiment is the same as that of the third embodiment. Omitted.

The method for producing diamond is the same as that of the third embodiment.

As shown in FIG. 4, the parallel plate electrodes 15a,
By narrowing the space between the electrodes 15b toward the gas supply pipe 3 of the reaction tube 1, the magnitude of the generated electric field can be changed for each electrode pair.

Here, the diamond particles 11 having a large particle size and a large mass are gas-supply pipe 3 side, that is, between the lower parallel plate electrodes, and the diamond particles 11 having a small particle size and a small mass are gaseous. The diamond particles 11 float on the exhaust pipe 4 side, that is, between the upper parallel plate electrodes, and the location of the diamond particles 11 changes according to the diameter of the diamond particles 11. The larger the particle size, the lower the diamond particles 11 are located due to their own weight.

Further, when the diamond particles 11 grow in crystal and have a large particle diameter, the diamond particles 11 are sequentially positioned below by their own weight.

Further, since the diamond particles 11 in the reaction tube 1 located between the parallel plate electrodes are positioned according to the particle size of the particles, the switch 29 is used to selectively supply power to each parallel plate electrode. By doing so, an electric field can be generated in a region where the diamond particles 11 having a specific particle size are present.

Thus, for example, when a diamond having a large particle diameter is desired, an electric field can be generated only in a region where the diamond particles 11 having a small particle diameter floating above exist, and diamond can be crystal-grown. ,
A relatively uniform diamond can be produced.

(Fifth Embodiment) FIG. 5 is a schematic diagram of a plasma apparatus used in a diamond manufacturing method according to a fifth embodiment of the present invention. In the fifth embodiment, diamond is manufactured using a parallel plate electrode type CVD method.

Within the quartz cylindrical reaction tube 16 used as the housing, the upper parallel plate electrode 17a and the lower parallel plate electrode 1a serving as electric field generating means are provided on the upper and lower sides, respectively.
7b. On the side surface of the reaction tube 16, four gas supply tubes 18 through which a raw material gas and a carrier gas flow from a gas inlet are provided. A gas exhaust pipe 19 for exhausting gas from a gas exhaust port is provided on the upper surface of the reaction tube 16. The upper parallel plate electrode 17a and the lower parallel plate electrode 17b are provided near the center of each of the upper surface and the bottom surface in the reaction tube 16, but are not limited thereto.

The amount of gas to be supplied is adjusted by adjusting the gas supply pipe 18.
Is performed by the gas inflow control valve 20 provided in each of
The amount of gas to be exhausted is adjusted by a gas exhaust amount adjusting valve 21 provided in the gas exhaust pipe 19. The gas is exhausted by an exhaust device 22 connected to the gas exhaust pipe 18.

A matching box 23 and a power supply 24 are connected to the upper parallel plate electrode 17a and the lower parallel plate electrode 17b, and power is supplied from the power supply 24 to use the upper parallel plate electrode 17a and the lower parallel plate electrode 17b to form a reaction tube. An electric field can be generated in 16.

Next, a method for producing diamond using the plasma apparatus of FIG. 5A will be described.

In the fifth embodiment, the diamond particles are suspended by applying a high frequency to the negatively charged diamond particles instead of suspending the diamond particles with a gas as in the first to fourth embodiments. is there.

First, the gas in the reaction tube 16 is sufficiently exhausted to 1 × 10 ⁻⁴ Pa through the gas exhaust tube 19 by the exhaust device 22 in advance. In the fifth embodiment, the particle diameter is set to 0.1 μm to 500 μm in advance.
Are arranged on the lower parallel plate electrode 17b.

Next, as in the first embodiment, a source gas for diamond and a carrier gas such as helium for facilitating the excitation of plasma are introduced into the reaction tube 16 using four gas supply tubes 18. . The flow rate and the ratio of the source gas to the carrier gas are set to be the same from the four gas supply tubes 18 so that the diamond particles 25 exist between the upper parallel plate electrode 17a and the lower parallel plate electrode 17b. Supply to

Next, a motivation to float the diamond particles 25 by applying a bias to the DC power source 26 is provided, and 800 W of power having a frequency of 13.56 MHz is input to the power source 24 and adjusted by the matching box 23. , Upper parallel plate electrode 17a and lower parallel plate electrode 1
An electric field by high frequency is generated in 7b, and the floating state of the diamond particles 25 is maintained.

As a result, the source gas is also turned into plasma by the carrier gas turned into plasma, and a reaction product is generated. Then, the reaction product grows into the diamond particles 25 with the diamond particles 25 in the floating state in the reaction tube 16 as nuclei, and diamond can be produced.

In order to keep the inside of the reaction tube 16 at a constant pressure, the gas is exhausted through a gas exhaust pipe 19 provided near the center of the upper part of the reaction tube 16.

In the fifth embodiment, the hydrogen gas flow rate is 50 cc / min, and the methane gas flow rate is 0.4 cc. / Min. Here, the hydrogen gas is effective in etching the non-diamond structure, and it is desirable that the hydrogen gas be mixed at least 20 times the methane gas. Examples of the raw material gas include methane, acetylene, butane, and the like in addition to methane, and methane is inexpensive and preferable as a volatile hydrocarbon gas.

FIG. 5B shows a cross section taken along the line XX ′ in FIG. 5A. FIG.
As shown in (b), the four gas supply pipes 18 are evenly provided on the side surface of the reaction tube 16.

As a result, the diamond particles 25 can be evenly distributed with reference to the central axis in the reaction tube 16, so that the reaction can be performed in a region where the plasma density is high.

[0080]

According to the present invention, the raw material gas is used not only for the growth of diamond but also for floating diamond particles. By growing the reaction product generated by decomposing the diamond into diamond particles, the suspended diamond particles and the reaction product can be efficiently reacted.

[Brief description of the drawings]

FIG. 1 is a schematic view of a plasma apparatus used in a method for producing a diamond according to a first embodiment of the present invention.

FIG. 2 is a schematic view of a plasma apparatus used in a method for producing a diamond according to a second embodiment of the present invention.

FIG. 3 is a schematic view of a plasma apparatus used in a method for producing a diamond according to a third embodiment of the present invention.

FIG. 4 is a schematic view of a plasma apparatus used in a method for producing a diamond according to a fourth embodiment of the present invention.

FIG. 5 is a schematic diagram of a plasma apparatus used in a method for producing a diamond according to a fifth embodiment of the present invention.

FIG. 6 is a schematic view of a plasma apparatus used in a conventional diamond manufacturing method.

[Explanation of symbols]

 1, 16, 31 Reaction tube 2, 27, 32 Induction coil 3, 18 Gas supply tube 4, 19 Gas exhaust tube 5 Inclined part 6, 20 Gas inflow control valve 7, 21, Gas exhaust control valve 8, 22, 41 Exhaust device 9,23 Matching box 10,24 Power supply 11,25,36 Diamond particle 12 Heating device 13 Step 14a, 14b, 15a, 15b Parallel plate electrode 17a Upper parallel plate electrode 17b Lower parallel plate electrode 26 DC power supply 28,29 Switch 33 High frequency power supply 34 Source gas supply device 35 Plasma gas supply device 37 Gas supply device for particle suspension 38 Vibration plate 39 Electromagnet 40 Power supply for electromagnet

Claims (11)

[Claims] 1. A method according to claim 1, wherein the source material gas is fed into the housing to float the diamond particles in the housing, and an electric field is applied to the source gas to decompose the source gas to produce a reaction product. A method for producing diamond, comprising reacting a reaction product. 2. The method according to claim 1, wherein the electric field is generated by a coil wound outside the housing. 3. The method according to claim 1, wherein the electric field is generated by a first electrode and a second electrode provided inside the case and arranged in parallel with each other. . 4. The method according to claim 3, wherein the reaction is performed by negatively charging the diamond particles. 5. The diamond production according to claim 1, wherein the reaction is performed while heating the diamond particles by a heating device provided outside the housing. Method. 6. A plasma device having an electric field generating means, a gas inlet, and a gas outlet provided in a housing, wherein the gas inlet is provided on a bottom surface of the housing, and A plasma apparatus, wherein a side surface of a body is formed in a step shape, and the electric field generating means is provided at each step. 7. A plasma device having an electric field generating means, a gas inlet, and a gas exhaust port provided in a housing, wherein the gas inlet is provided on a bottom surface of the housing, and the electric field generating means comprises: It is composed of a plurality of electrode pairs having a pair of two electrodes provided inside the housing, and is provided so that an electrode interval of each of the electrode pairs decreases toward the gas inlet. Plasma equipment. 8. The plasma apparatus according to claim 6, wherein a plurality of the gas exhaust ports are provided. 9. A plasma apparatus having an electric field generating means, a gas inlet, and a gas exhaust port provided in a housing, wherein the gas inlet is provided on a side surface of the housing, and A plasma apparatus, wherein the means comprises electrodes provided on the upper and lower sides of the housing. 10. A method for producing diamond using the plasma device according to claim 6, wherein diamond gas is suspended in the housing by feeding a raw material gas into the housing. By applying an electric field to the source gas, the source gas is decomposed into a reaction product,
A method for producing diamond, comprising reacting the diamond particles with the reaction product. 11. A method for producing diamond using the plasma apparatus according to claim 9, wherein high-frequency power is supplied to the electrode to cause diamond particles to float in the housing, and an electric field is applied to the source gas. Wherein the source gas is decomposed into a reaction product by reacting the diamond particles with the reaction product.