JP5914041B2 - Single crystal diamond manufacturing method and single crystal diamond manufacturing apparatus - Google Patents

Description

  The present invention relates to a single crystal diamond manufacturing method and apparatus for supplying a source gas and growing single crystal diamond using plasma, and more specifically, a vapor phase growth method using plasma (hereinafter referred to as “plasma CVD”). The present invention relates to a single crystal diamond manufacturing method and apparatus for growing single crystal diamond on the surface of one kind of diamond substrate of an electrode pair generating plasma.

  Industrial diamond is used in cutting tools, punch / die dies, and the like, and there is a demand for stable supply of large-sized single crystal diamond and cost reduction. A typical method for producing diamond is a plasma CVD method. Japanese Patent Application Laid-Open No. 5-5179 (Patent Document 1) discloses a method for producing a diamond film using a plasma jet and a method using a microwave. A method for producing a diamond film by a wave plasma CVD method is described. In the microwave plasma CVD method, a source gas is turned into plasma by microwaves (2.45 GHz) to deposit diamond on a substrate. Compared with other conventional plasma CVD methods, the diamond can be grown more stably.

FIG. 5 is a schematic configuration diagram of a conventional microwave plasma CVD apparatus for manufacturing a diamond film disclosed in Patent Document 1. In FIG. This microwave plasma CVD apparatus is composed of a quartz tube 120, a substrate to be processed 121 is placed in the center, and a microwave is irradiated from a microwave oscillator 123 through a waveguide 122, and the reaction gas 124 is changed to a plasma state. To do. Therefore, the reaction gas 124 for forming diamond is supplied to the substrate 121 from above. In the example of Patent Document 1 shown in FIG. 5, a Si substrate is used as the substrate to be processed 121, and H ₂ , CH ₄ , and silane (SH ₄ ) are used as reaction gases. The reaction gas 124 is supplied and the exhaust system is operated, and the microwave is irradiated by the macro wave oscillator 123 to increase the output to 1000 ° C. First, a silicon carbide (SiC) film is grown on a Si substrate. The flow rate of SH ₄ and CH ₄ is gradually decreased in 5 hours, the formed film is changed from SiC to diamond, and the diamond film is grown by holding for 10 hours. However, in the microwave plasma CVD apparatus of FIG. 4 described in the cited document 1, it is difficult to form diamond nuclei.

In JP 2007-238377 A (Patent Document 2), a base material (single crystal iridium) is set on a negative voltage application electrode, a DC voltage of a certain value is applied as a bias treatment, and diamond nucleation is performed. After that, it is described that single crystal diamond is grown by microwave plasma CVD. Japanese Patent Application Laid-Open No. 2005-85785 (Patent Document 3) describes that a microwave or millimeter wave of 1 GHz or more is used as an excitation source for generating plasma, and a single crystal diamond thin film is formed on a diamond substrate by plasma CVD. Has been.
However, in the microwave plasma CVD method, the direct current plasma CVD method is superior in terms of the high consumption efficiency of input power and the high growth rate. In JP 2010-95408 A (Patent Document 4), a parallel plate type counter electrode formed of a refractory metal such as Mo is used, a uniform electric field is applied between the electrodes, and a reaction gas is supplied. A direct current plasma CVD method is described in which direct current plasma is generated to grow an epitaxial diamond film close to a single crystal.

JP-A-5-5179 JP 2007-238377 A JP 2005-85785 A JP 2010-95408 A

In the microwave plasma CVD methods described in the cited documents 1 to 3, a relatively complicated and expensive microwave generating means including the waveguide 122 and the microwave oscillator 123 as shown in FIG. Furthermore, the microwave plasma CVD method is less efficient and slower than the direct current plasma CVD method with respect to the consumption efficiency of input power and the speed of growth, and can synthesize single crystal diamond efficiently at a lower cost. Was demanded.
However, in the DC plasma CVD method as described in Patent Document 4, it is relatively difficult to generate plasma and irradiate the plasma to a predetermined position on the substrate surface for a long time uniformly and stably. Compared with the wave plasma CVD method, the quality of the growing single crystal diamond tended to deteriorate.
Further, in the process of growing single crystal diamond on the seed diamond of the substrate by plasma CVD, continuous operation for a long time is indispensable. Under stable plasma, when carbon species in the source gas such as methane gas are deposited on the electrode surface, single crystal diamond grows gradually to become a red hot spot, and the plasma is unstable starting from there. At last, arc discharge was reached and the growth was stopped.

  Accordingly, an object of the present invention is to provide a single crystal diamond manufacturing method and a manufacturing apparatus using the plasma CVD method capable of maintaining the generated plasma more stably and growing single crystal diamond at a low cost. It is.

  The present invention has been proposed in order to solve the above-described problems. The first aspect of the present invention is to supply a source gas and use a plasma generated between the electrodes on the substrate of one electrode. In the single crystal diamond manufacturing method for growing single crystal diamond, the position of the plasma is adjusted by a magnetic field formed by a magnetic field generating means.

  In a second aspect of the present invention, in the first aspect, two or more magnetic field generating means for generating the magnetic field are provided, and the strength and direction of each magnetic field formed by the magnetic field generating means are adjusted. In this way, the direction of the synthetic magnetic field can be freely changed.

  According to a third aspect of the present invention, in the second aspect, the magnetic field generating means adjusts the position of the plasma by the synthetic magnetic field acting substantially parallel to the surface on the substrate on which the single crystal diamond is grown. A method for producing single crystal diamond in which is provided.

  According to a fourth aspect of the present invention, in the first, second, or third aspect, a rotating magnetic field generating unit is provided, and the rotating magnetic field generating unit includes a pair of magnetic field coils whose magnetic field periodically changes. And a single crystal diamond manufacturing method in which a rotating magnetic field is formed such that the phase of each magnetic field formed by the pair of magnetic field coils is shifted and the plasma rotates and swings on the substrate.

  A fifth aspect of the present invention is the method for producing single crystal diamond according to any one of the first to fourth aspects, wherein the magnetic field generating means is a magnetic field coil.

  A sixth aspect of the present invention is the method for producing single crystal diamond according to any one of the first to fifth aspects, wherein the plasma generation voltage applied between the electrodes is a pulse voltage.

  A seventh aspect of the present invention is the method for producing single crystal diamond according to the sixth aspect, wherein a fluctuation having a frequency smaller than a pulse frequency is given to the output of the pulse voltage, and the magnitude of the plasma on the substrate is fluctuated. It is.

  An eighth aspect of the present invention is the method for producing single crystal diamond according to the sixth or seventh aspect, wherein the pulse voltage has a pulse width of 1 μs to 10 μs and a pulse frequency of 10 kHz to 200 kHz.

  According to a ninth aspect of the present invention, there is provided a vacuum vessel, a raw material gas supply device for supplying a raw material gas into the vacuum vessel, an electrode pair disposed in the vacuum vessel, and a plasma generating voltage across the electrode pair. In the single crystal diamond manufacturing apparatus comprising at least a power supply for applying a magnetic field, a magnetic field generator for adjusting a plasma position by generating a magnetic field is provided on the outer periphery of the vacuum vessel.

  According to a tenth aspect of the present invention, in the ninth aspect, two or more magnetic field generators are provided, and the strength and direction of each DC magnetic field and / or AC magnetic field formed by the magnetic field generator are adjusted. Thus, a synthetic magnetic field and / or a synthetic rotating magnetic field is formed, and the intensity and direction of the synthetic magnetic field and / or the rotational speed and strength of the synthetic rotating magnetic field are freely adjusted.

  An eleventh aspect of the present invention is the single crystal diamond manufacturing apparatus according to the ninth or tenth aspect, wherein the magnetic field generator is a magnetic field coil.

  A twelfth aspect of the present invention is the single crystal diamond manufacturing apparatus according to the ninth, tenth or eleventh aspect, wherein the plasma generating voltage power source applied between the electrodes is a pulse voltage power source.

According to the first aspect of the present invention, in the single crystal diamond manufacturing method of supplying a source gas and growing single crystal diamond on the substrate of one electrode using plasma generated between the electrodes, the magnetic field generating means Since the position of the plasma is adjusted by the magnetic field to be formed, the plasma can be adjusted to a predetermined position or a center position on the substrate, or a predetermined fluctuation can be imparted to the plasma. It can be grown more stably. The magnetic field generating means is arranged so that the position of the plasma can be adjusted. In the case of an electromagnet, the magnetic field generating means can be adjusted according to the applied current and the arrangement position thereof. In the case of a permanent magnet, the arrangement position is finely adjusted. Thus, the position of the plasma can be controlled.
As a result of the inventors' diligent research, plasma was generated between the electrode and the single crystal diamond growth substrate using a plasma generation power source that was simpler than the plasma generation mechanism using microwaves. It is discovered that a high-quality single-crystal diamond can be grown by applying the plasma more stably or periodically, and a manufacturing apparatus can be operated for a long time. The invention has been completed. In particular, when the plasma is oscillated by an alternating magnetic field, and the plasma is irradiated while the plasma is oscillating on the electrode surface on the substrate side with the seed diamond, the carbon seed is prevented from depositing and partially growing, and for a long time. Operation of a stable multi-single crystal diamond manufacturing apparatus is possible, and continuous operation for 12 to 24 hours or more can be achieved. The growth rate can be set to 30 μm / h to 50 μm / h or more, and single crystal diamond having a thickness of 1 mm or more can be grown in 24 hours.
Therefore, according to the first aspect of the present invention, the generation of a magnetic field that forms a magnetic field capable of adjusting the plasma to a predetermined position or a center position on the substrate or imparting a predetermined fluctuation to the plasma. By using the means, a stable and good quality single crystal diamond can be produced continuously or intermittently for a relatively long time.

  According to the second aspect of the present invention, two or more magnetic field generating means for generating the magnetic field are disposed, and the strength and direction of each magnetic field formed by the magnetic field generating means are adjusted to adjust the synthesized magnetic field. Since the direction is freely changed, the plasma can be adjusted to a predetermined position on the substrate more reliably, and single crystal diamond can be grown more stably. Alternatively, it is possible to grow single crystal diamond more stably by applying periodic fluctuation in a desired direction to the plasma. As described above, the present inventors have clarified that single crystal diamond can be stably grown for a longer period of time by periodically oscillating the plasma. Since the two or more magnetic field generating means generate a synthetic magnetic field having a desired direction and strength, in the case of an electromagnet, it can be adjusted by an applied current and an arrangement position thereof. In the case of a permanent magnet, the arrangement position can be finely adjusted to adjust the direction of the synthetic magnetic field.

  According to a third aspect of the present invention, the magnetic field generating means is arranged to adjust the position of the plasma by the synthetic magnetic field acting substantially parallel to the surface on the substrate on which the single crystal diamond is grown. Therefore, the position of the plasma can be adjusted along the substrate surface, for example, it can be adjusted to the center position or a predetermined position on the substrate. Alternatively, the plasma can be periodically oscillated on the substrate surface. Therefore, single crystal diamond can be grown more stably and over a long time.

  According to the fourth aspect of the present invention, a rotating magnetic field generating means is provided, and the rotating magnetic field generating means is composed of a pair of magnetic field coils whose magnetic fields periodically change, and is formed by the pair of magnetic field coils. Since the magnetic field is formed such that the phase of each magnetic field is shifted and the plasma rotates and swings on the substrate, the plasma generated between the electrode and the substrate rotates and swings, and the plasma is more reliably generated. It can be swung on the substrate. Therefore, single crystal diamond can be grown more stably and over a long time. As described above, as a result of intensive studies by the present inventors, it has been discovered that the single crystal diamond can be stably grown when the plasma fluctuates, and the present invention has been completed. By providing the generating means, the plasma can be rotated and swung on the substrate.

  According to the fifth aspect of the present invention, since the magnetic field generating means is a magnetic field coil, the strength and direction of the magnetic field can be adjusted relatively easily. When the applied voltage is a DC voltage, the magnitude, positive / negative, etc. of the applied voltage, and in the case of an AC voltage, the frequency, phase, waveform, etc. can be adjusted for each magnetic field generating means to form a desired magnetic field or synthetic magnetic field. it can. Therefore, it is possible to grow single crystal diamond more suitably by adjusting the position and oscillation of the plasma.

  According to the sixth aspect of the present invention, since the plasma generation voltage applied between the electrodes is a pulse voltage, the plasma can be generated using a relatively inexpensive power source. Furthermore, when pulse voltage is used, high-voltage and large-current glow-arc transition regions and abnormal glow discharge plasma can be used, and after-glow discharge can also be used, reducing manufacturing costs. Can be

  According to the seventh aspect of the present invention, a fluctuation having a frequency smaller than a pulse frequency is given to the output of the pulse voltage, and a fluctuation is given to the size of the plasma on the substrate. Single crystal diamond can be grown over the entire area. As described above, the present inventors have discovered that the plasma can grow single crystal diamond more suitably by having periodic fluctuations in energy and plasma formation range, and completed the present invention. I arrived.

  According to the eighth aspect of the present invention, since the pulse width of the pulse voltage is 1 μs to 10 μs and the pulse frequency is 10 kHz to 200 kHz, plasma suitable for the growth of single crystal diamond can be generated. When the pulse width is less than 1 μs and the pulse frequency is less than 10 kHz, it is difficult to generate a suitable plasma continuously. On the other hand, when the pulse width exceeds 10 μs or the pulse frequency exceeds 200 kHz, excessive energy is supplied and energy efficiency is reduced.

  According to the ninth aspect of the present invention, since the magnetic field generator for adjusting the position of the plasma by generating a magnetic field is provided on the outer periphery of the vacuum vessel, the plasma is adjusted to a predetermined position or a center position on the substrate. Or a predetermined fluctuation can be imparted to the plasma, and the single crystal diamond can be grown more stably and a single crystal diamond having a predetermined crystallinity and size can be provided. The magnetic field generator is arranged so that the position of the plasma can be adjusted. In the case of an electromagnet, it can be adjusted according to the applied current and the arrangement position thereof. In the case of a permanent magnet, the arrangement position is finely adjusted. Thus, the position of the plasma can be controlled.

  According to the tenth aspect of the present invention, two or more magnetic field generators are provided, and the strength and direction of each DC magnetic field and / or AC magnetic field formed by the magnetic field generator is adjusted to produce a combined magnetic field. And / or a synthetic rotating magnetic field is formed, and the strength and direction of the synthetic magnetic field and / or the rotational speed and strength of the synthetic rotating magnetic field are freely adjusted, so that the plasma is more reliably placed at a predetermined position on the substrate. The plasma can be rotated and oscillated. As described above, the inventors of the present invention are more stable and long when the plasma generated between the electrode and the substrate is adjusted to a predetermined position and when the plasma is further rotated and oscillated. It has been discovered that single crystal diamond can be grown over time, and the present invention has been completed. Two or more of the magnetic field generators can generate a synthetic magnetic field having a desired direction and strength, and can form a rotational synthetic magnetic field that rotates and swings the plasma as necessary.

  According to the eleventh aspect of the present invention, since the magnetic field generator is a magnetic field coil, the strength and direction of the magnetic field can be adjusted relatively easily by the supplied current and the applied voltage.

  According to the twelfth aspect of the present invention, since the plasma generating voltage power source applied between the electrodes is a pulse voltage power source, the plasma can be generated using a relatively inexpensive power source. Furthermore, when a pulse voltage is used, it is possible to use a glow-arc transition region or an abnormal glow discharge plasma with a high voltage and a large current, and after glow discharge can be used. Manufacturing cost can be reduced.

FIG. 1 is a schematic configuration diagram of a single crystal diamond manufacturing apparatus according to the present invention. FIG. 2 is a cross-sectional view showing the arrangement of the magnetic field generator in the single crystal diamond manufacturing apparatus according to the present invention. FIG. 3 is an explanatory view for explaining the fluctuation of plasma generated in the parallel electrode and the growth substrate of the single crystal diamond manufacturing apparatus according to the present invention. FIG. 4 is a schematic diagram showing a pulse voltage supplied to the single crystal diamond manufacturing apparatus according to the present invention. FIG. 5 is a schematic configuration diagram of a conventional micro CVD apparatus for producing a diamond film.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
<Example 1>
FIG. 1 is a schematic configuration diagram of a single crystal diamond manufacturing apparatus 2 according to the present invention. In Example 1 of the single crystal diamond manufacturing apparatus 2 shown in FIG. 1A, an X-direction magnetic field generator is provided in which a growth portion 6 and an electrode portion 8 are provided in a vacuum chamber 4 and further generates an X-direction magnetic field Bx. 10 and a Y-direction magnetic field generator (not shown) for generating an X-direction magnetic field By are provided. The position and fluctuation of the plasma generated in the vacuum chamber 4 are adjusted by the combined magnetic field of the X direction magnetic field Bx and the X direction magnetic field By. Such plasma control by a magnetic field will be described later.

As shown in FIG. 1A, the growth section 6 includes a growth substrate 14 made of seed diamond at the center of the substrate electrode 12, and an auxiliary heater 40 that heats the substrate around the substrate electrode 12. And is attached to the vacuum chamber 4 by the substrate support 36. The substrate support portion 36 is rotatable and can be provided so as to be movable up and down, and the position can be adjusted. The substrate electrode 12 is connected to an external pulse power supply 18 through an internal conductor 32a, a resistor 30, and substrate-side conductors 22 and 32, and one end thereof is grounded through an earth-side conductor 34. Here, the resistance value of the resistor 30 is 0 to several Ω. The substrate electrode 12 is made of a high melting point metal or alloy such as molybdenum or tungsten.
The electrode unit 8 includes a plate electrode 16 and a plate electrode support unit 38 and is attached to the vacuum chamber 4, and the plate electrode 16 is connected to the pulse power source 18 through a plate electrode side conductor 20. The plate electrode support portion 38 is provided with an internal supply pipe 28 a and is connected to the raw material gas supply device 26 via the raw material gas supply pipe 28. The source gas supply device 26 has a cylinder such as hydrogen, argon, methane, oxygen, and nitrogen, and can supply a source gas obtained by mixing methane as a source with other gases. The source gas is supplied from a supply port on the electrode surface via an internal supply pipe 28a.

As shown in FIG. 1 (1A), the vacuum chamber 4 is provided with an exhaust port 24 and exhausted by a turbo molecular pump or an oil rotary vacuum pump. Therefore, the following steps (1) to (5) are sequentially performed, and the steps (2) to (4) are continuously and simultaneously progressed to grow single crystal diamond on the substrate surface 14a.
(1) Exhaust, (2) Supply of source gas, (3) Application of pulse voltage, (4) Generation of plasma, (5) Growth of single crystal diamond In the “(1) Exhaust”, as described above, The vacuum chamber 4 is evacuated and the ultimate pressure is about 1 × 10 ⁻⁴ . In the “(2) Supply of source gas”, a mixed gas of hydrogen, nitrogen, argon and oxygen including methane as a source is supplied as a source gas, and when growing single crystal diamond by plasma CVD, The inside is maintained at about 10-30 kPa. When the amount of hydrogen is supplied at 500 CC / min, methane is preferably supplied at about 60 cc / min, and other gases are preferably supplied in appropriate amounts.

In “(3) Application of pulse voltage”, a pulse voltage is applied between the plate electrode 16 and the substrate electrode 12 by the pulse power source 18 and the pulse width is in the range of 1 μs to 10 μs and the pulse frequency is in the range of 10 kHz to 200 kHz. Is done. A negative voltage is applied so that the plate electrode 16 has a negative voltage. The high-voltage pulse power is 1.0 kV · 20 A, and can be adjusted so that the growth substrate 14 satisfies the growth conditions by plasma CVD. Furthermore, it is more preferable that the pulse voltage has a fluctuation with a period longer than the pulse period, which will be described later.
In the “(4) generation of plasma”, as described above, a pulse voltage is applied between the plate electrode 16 and the substrate electrode 12 and the source gas is supplied, whereby the plate electrode 16 and the growth substrate 14 are supplied. Plasma is generated in the meantime. When a pulse voltage is used, it is possible to use a glow-arc transition region with a high voltage and a large current or an abnormal glow discharge plasma, and it is possible to grow single crystal diamond in a relatively short time. In the “(5) Growth of single crystal diamond” step, single crystal diamond is grown while plasma is generated. Note that, under the growth conditions of single-crystal diamond in plasma CVD, the substrate electrode 12 is heated to 950 ° C. to 1500 ° C., more preferably 950 ° C. to 1150 ° C., and the auxiliary heater 40 can be used in addition to heating by plasma. is there.

In the single crystal diamond manufacturing apparatus 2 shown in FIG. 1 (1A), the X-direction magnetic field Bx
And the Y-direction magnetic field By can be generated, and the position of the plasma can be adjusted by the combined magnetic field. For example, the strength and direction of the X-direction magnetic field Bx can be adjusted by changing the magnitude and positive / negative of the voltage and current applied to the X-direction magnetic field generator, and the Y-direction magnetic field By is also the same. It is possible to adjust the position of the plasma by changing the strength and direction of the plasma. In particular, the electrode temperature rises to 950 ° C. to 1500 ° C., but in the temperature rise process, the position of the plasma is dominated by variations in the temperature rise, etc., concentrates in a high temperature region where electron emission is good, and the plasma is biased. Therefore, it is possible to adjust the plasma position to the center position by the synthetic magnetic field. Further, as will be described later, during the growth of single crystal diamond, the plasma preferably has a predetermined period of fluctuation (or referred to as “fluctuation”), and the direction of the synthetic magnetic field is periodically changed to change the plasma. It can be swung. In addition, it is more desirable that the plasma is observed by providing a plasma measurement Langmuir probe and a radiation thermometer and provided with a visual window.

<Example 2>
(1B) of FIG. 1 shows Example 2 of the single crystal diamond manufacturing apparatus 2 according to the present invention. In the following, members having the same function are denoted by the same reference numerals, and the same description is omitted. In the single crystal diamond manufacturing apparatus 2 of (1B), the ion collision wall 42 is provided on the upper part of the installation part 44 made of an insulating material, and positive ions scattered outside the growth substrate 14 can collide and be adsorbed. A DC power supply 46 is connected to the ion collision wall 42 through a conducting wire 48 and a bias resistor 50. The ion collision wall 42 is set as a negative electrode and adsorbs positive ions. The ion collision wall 42 is insulated from the vacuum chamber 4 and the substrate electrode 12. Therefore, high-efficiency single crystal diamond can be grown by generating plasma with high efficiency.

  FIG. 2 is a cross-sectional view showing the arrangement of the magnetic field generator in the single crystal diamond manufacturing apparatus according to the present invention. (2A) of FIG. 2 shows an XX cross-sectional view of Example 1 of FIG. As described above, the X-direction magnetic field generator 10 that generates the X-direction magnetic field Bx and the Y-direction magnetic field generator 11 that generates the Y-direction magnetic field By are disposed outside the vacuum chamber 4. The position of the plasma can be adjusted by the combined magnetic field of the X-direction magnetic field Bx and the Y-direction magnetic field By. The magnitude and positive / negative of the applied voltage and current are changed, and the plasma position is adjusted by the strength and direction of the combined magnetic field. Is possible.

<Example 3>
(2B) of FIG. 2 shows Example 3 of the single crystal diamond manufacturing apparatus according to the present invention. In Example 2 shown in (2B), a first rotating magnetic field generator 15 and a second magnetic field generator 17 are provided. For example, an AC voltage having a cosine wave phase is applied to the first rotating magnetic field generator 15, and an AC voltage having a cosine wave having a phase different from that of the first rotating magnetic field generator 15 is applied to the second rotating magnetic field generator 17. When applied, the magnetic field generated by the first rotating magnetic field generator 15 and the second rotating magnetic field generator 17 becomes a combined rotating magnetic field. That is, an AC magnetic field is applied and the phase is shifted by 90 ° back and forth. Therefore, the generated plasma can be rotated while being swung on the growth substrate. It suffices if a combined rotating magnetic field is formed, and the tip of the magnetic field vector may draw an ellipse, and it is desirable that the magnetic field vector be closer to a perfect circle. At this time, the combined magnetic field generated by the magnetic field generators 10 and 11 is used for adjusting the bias of the plasma. The synthetic rotating magnetic field continues to be applied as it is.

<Example 4>
FIG. 2 (2C) shows a fourth embodiment of the single crystal diamond manufacturing apparatus according to the present invention. The fourth embodiment is a modification of the third embodiment, and the attachment positions of the first rotating magnetic field generator 15 and the second magnetic field generator 17 are different. In the fourth embodiment, as in the third embodiment, it is possible to form a synthetic rotating magnetic field and rotate the plasma on the growth substrate to oscillate (also referred to as “oscillating rotation”).

FIG. 3 is an explanatory view for explaining the fluctuation of plasma generated in the parallel electrode 16 and the growth substrate 14 of the single crystal diamond manufacturing apparatus according to the present invention. (3A) to (3C) are examples of the present invention, and (3D) is a comparative example. As shown in the comparative example of (3D), when the carbon deposit 58 adheres to the substrate electrode 12 in the vicinity of the growth substrate 14, it gradually grows to become a red hot spot, and arc discharge is generated. Generation must be stopped. Here, the carbon deposit 58 is a partially grown carbon seed film deposited.
In (3A), as shown in (2B) and (2C) of FIG. 2, a combined rotating magnetic field is formed by a pair of rotating magnetic field generators, and rotationally oscillating plasmas 51 and 52 are formed. As shown by, the substrate is rotated on the growth substrate 14. That is, it oscillates and oscillates through the state of the oscillating plasma 51 shown by the solid line and the oscillating plasma 52 shown by the one-dot broken line. Therefore, adhesion and growth of the carbon species are suppressed, and arc discharge can be prevented from occurring.

In FIG. 3 (3B), plasma is oscillated on the growth substrate 14 by the magnetic fields of the magnetic field generators 10 and 11 shown in FIG. That is, a magnetic field that oscillates as shown by the two-dot broken line arrow is formed, and the plasma oscillates through the oscillating plasma 53 indicated by the solid line and the oscillating plasma 54 indicated by the one-dot broken line. Therefore, adhesion and growth of the carbon species are suppressed, and arc discharge can be prevented from occurring.
(3C) of FIG. 3 is an explanatory diagram when the fluctuation of the period larger than the pulse period is given to the pulse voltage, and the plasma is expanded and contracted. As will be described later, when the pulse voltage has fluctuations larger than the pulse period, when the energy by the applied voltage is large, the expanded plasma shown by the solid line is formed, and when the energy is low, the contraction shown by the one-dot broken line Plasma 56 is formed. That is, the plasma oscillates by repeating expansion and contraction. Even in this case, the adhesion and growth of the carbon species are suppressed, and the occurrence of arc discharge can be prevented.

FIG. 4 is a schematic diagram showing a pulse voltage supplied to the single crystal diamond manufacturing apparatus according to the present invention. (4A) is a schematic diagram showing the shape of the pulse voltage when the pulse voltage is supplied at the pulse period Tp and the value of the pulse voltage has a fluctuation period Tf larger than the pulse period Tp. Here, such a pulse voltage is referred to as a “fluctuation pulse voltage”. The fluctuation pulse voltage has a V ₀ of −100 V to −5 kV, and the repetition fp of the pulse voltage is such that fp = 1 / Tp is 10 kHz to 200 kHz, so that plasma can be sufficiently generated. However, the fluctuation pulse voltage has an output fluctuation f of 0.1 Hz to 1000 Hz, expressed by f = 1 / Tf, and the output fluctuates periodically. Therefore, as shown in (3C) of FIG. 3, the plasma repeatedly expands and contracts, the adhesion and growth of the carbon species are suppressed, and the occurrence of arc discharge can be prevented. The magnitude of the output fluctuation is given by ((V ₋ −V ₊ ) ² ) ^1/2 as shown in (4A) of FIG. 4, and the magnitude is 5% to 20% of V _0. It is preferable that it is a magnitude | size.
FIG. 4 (4B) shows a schematic diagram of a pulse shape in which the output of the pulse power is substantially constant. In this case, as described above, it is possible to use a glow-arc transition region with a high voltage and a large current or an abnormal glow discharge plasma, and it is possible to use afterglow discharge or the like. It is. Further, if the pulse voltage V ₀ is −100 V to −5 kV and the pulse voltage repetition fp is fp = 1 / Tp is 10 kHz to 200 kHz, plasma can be sufficiently generated.

  According to the present invention, the plasma can be adjusted to a predetermined position or center position on the substrate, or a predetermined fluctuation can be imparted to the plasma, and single crystal diamond can be grown more stably. . As a result of the inventors' diligent research, plasma was generated between the electrode and the single crystal diamond growth substrate using a plasma generation power source that was simpler than the plasma generation mechanism using microwaves. It is discovered that a high-quality single-crystal diamond can be grown by applying the plasma more stably or periodically, and a manufacturing apparatus can be operated for a long time. The invention has been completed. In particular, when the plasma is oscillated by an alternating magnetic field, and the plasma is irradiated while the plasma is oscillating on the electrode surface on the substrate side with the seed diamond, the carbon seed is prevented from depositing and partially growing, and for a long time. Operation of a stable multi-single crystal diamond manufacturing apparatus is possible, and continuous operation for 12 to 24 hours or more can be achieved. The growth rate can be set to 30 μm / h to 50 μm / h or more, and single crystal diamond having a thickness of 1 mm or more can be grown in 24 hours. Accordingly, large single crystal diamond used for cutting tools, punch / die dies, and the like can be stably supplied as industrial diamond, and the cost can be reduced.

2 Single crystal diamond manufacturing apparatus 4 Vacuum chamber 6 Growth section 8 Electrode section 10 X direction magnetic field generator 11 Y direction magnetic field generator 12 Substrate electrode 14 Growth substrate 15 First rotation magnetic field generator 16 Flat plate electrode 17 Second rotation magnetic field Generator 18 Pulse power supply 20 Flat electrode side conductor 22 Substrate side conductor 24 Exhaust port 26 Source gas supply device 28 Source gas supply pipe 28a Internal supply pipe 30 Resistance 32 Substrate side conductor 32a Internal conductor 34 Ground side conductor 36 Substrate support part 38 Electrode Support section 40 Auxiliary heater 42 Ion collision wall 44 Installation section 46 DC power supply 48 Conductor 50 Bias resistance 51 Rotating oscillating plasma 52 Rotating oscillating plasma 53 Oscillating plasma 54 Oscillating plasma 55 Expanding plasma 56 Contracting plasma 57 Plasma 58 Carbon deposits Bx X direction magnetic field By Y direction magnetic field Tp Pulse period Tf Fluctuation period

Claims (9)

In a single crystal diamond manufacturing method in which source gas is supplied and single crystal diamond is grown on a substrate of one electrode using plasma generated between the electrodes, the position of the plasma is adjusted by a magnetic field generated by a magnetic field generating means A voltage for generating plasma applied between the electrodes is a pulse voltage, and a fluctuation having a frequency smaller than a pulse frequency is given to an output of the pulse voltage, and a fluctuation is given to the magnitude of the plasma on the substrate. A method for producing single crystal diamond, which is characterized. 2. The magnetic field generating means for generating the magnetic field is provided in two or more, and the direction and direction of the combined magnetic field is freely changed by adjusting the strength and direction of each magnetic field formed by the magnetic field generating means. Single-crystal diamond manufacturing method. The single crystal diamond manufacturing method according to claim 2, wherein the magnetic field generating means is arranged to adjust the position of the plasma by the synthetic magnetic field acting substantially parallel to the surface on the substrate on which the single crystal diamond is grown. Method. Rotating magnetic field generating means is provided, and the rotating magnetic field generating means includes a pair of magnetic field coils whose magnetic fields periodically change, and the plasma is generated by shifting the phase of each magnetic field formed by the pair of magnetic field coils. 4. The method for producing single crystal diamond according to claim 1, wherein a rotating magnetic field is formed so as to rotate and swing on the substrate. The method for producing single crystal diamond according to claim 1, wherein the magnetic field generating means is a magnetic field coil. 6. The method for producing single crystal diamond according to claim 1, wherein the pulse voltage has a pulse width of 1 μs to 10 μs and a pulse frequency of 10 kHz to 200 kHz. A vacuum vessel, a source gas supply device for supplying a source gas into the vacuum vessel, an electrode pair disposed in the vacuum vessel, and a power source for applying a plasma generating voltage to the electrode pair In the single crystal diamond manufacturing apparatus, a magnetic field generator for adjusting a plasma position by generating a magnetic field is provided on the outer periphery of the vacuum vessel , and a voltage for generating plasma applied between the electrodes is a pulse voltage, and the pulse voltage giving fluctuations having a frequency of the pulse frequency at the output of the single-crystal diamond production apparatus provided characterized Rukoto fluctuation in size of the plasma on the substrate. Two or more magnetic field generators are disposed, and a combined magnetic field and / or a combined rotating magnetic field is formed by adjusting the strength and direction of each DC magnetic field and / or AC magnetic field formed by the magnetic field generator, The single crystal diamond manufacturing apparatus according to claim 7 , wherein the intensity and direction of the synthetic magnetic field and / or the rotational speed and intensity of the synthetic rotating magnetic field are freely adjusted. The single crystal diamond manufacturing apparatus according to claim 7 or 8 , wherein the magnetic field generator is a magnetic field coil.

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