JP6359805B2 - Diamond composite, method for producing diamond composite, and method for producing single crystal diamond - Google Patents

Description

  The present invention relates to a diamond composite, a single crystal diamond, a method for producing the same, and a diamond tool, and more specifically, a diamond composite capable of improving the performance of the diamond tool, a single crystal diamond, and The present invention relates to these manufacturing methods and a diamond tool including the single crystal diamond.

  Conventionally, diamond tools such as cutting tools and wear-resistant tools have been made of natural diamond or diamond produced by a high pressure high temperature method (HPHT). Natural diamonds vary greatly in quality and the supply is not stable. In addition, diamond produced by the high-temperature and high-pressure synthesis method has a small quality variation and a stable supply amount, but has a problem that the cost of production equipment is high.

  On the other hand, as another synthesis method of diamond, there is a gas phase synthesis method such as a hot filament CVD (Chemical Vapor Deposition) method, a microwave excitation plasma CVD method or a DC plasma CVD method. In this method, first, a diamond seed crystal manufactured by a high-temperature and high-pressure synthesis method is prepared, and a diamond composite is obtained by growing single crystal diamond (epitaxial growth layer) on the surface of the diamond seed crystal. Then, by separating the diamond seed crystal from this diamond composite, single crystal diamond can be obtained. For example, Japanese Unexamined Patent Application Publication No. 2009-59798 (hereinafter referred to as Patent Document 1) discloses a diamond electronic device in which a diamond semiconductor layer is formed by a microwave plasma CVD method on a diamond substrate manufactured by a high-temperature and high-pressure synthesis method. Has been.

JP 2009-59798 A

  As described above, since the diamond seed crystal used in the vapor phase synthesis method is manufactured by the high-temperature and high-pressure synthesis method, the cut substrate surface includes a portion where the crystal growth direction is different. Therefore, this diamond seed crystal includes a plurality of growth sectors having different amounts of impurities and defects introduced. Since such growth sectors have different polishing and etching rates of the substrate, a step is formed at the boundary between the growth sectors by polishing or etching. When single crystal diamond is grown on a diamond substrate with a step formed, a plurality of growth sectors are also formed in the single crystal diamond. When this is used as a tool material, the boundary between the plurality of growth sectors is formed. The present inventor has found a problem that scratches or the like are likely to occur in the work material due to the step in the portion.

  It is also possible to prepare a crystal containing only a single growth sector by reducing the size of the diamond seed crystal. However, in this case, there is a problem that it is difficult to grow a large single crystal diamond.

  The present invention has been made in view of the above problems, and its object is to provide a diamond composite having a large size and capable of improving the performance of a diamond tool, single crystal diamond, a method for producing the same, and the method. It is to provide a diamond tool comprising single crystal diamond.

  The method for producing a diamond composite according to the present invention includes a step of preparing a diamond seed crystal including a plurality of growth sectors, and a single crystal diamond is grown on the surface of the diamond seed crystal by a vapor phase synthesis method. The process of obtaining. The step of obtaining the diamond composite includes a temperature raising step of heating the diamond seed crystal before reaching the growth temperature of the single crystal diamond. In the temperature raising step, the diamond seed crystal is heated in an atmosphere containing at least one of methane gas and inert gas. In the temperature raising step, the diamond seed crystal may be heated in an atmosphere containing at least one of methane gas, ethane gas, and inert gas.

  In the case of performing a gas phase synthesis method using a diamond seed crystal having a large size including a plurality of growth sectors, the present inventor has obtained a single crystal diamond (that is, a single crystal composed of a single growth sector) with superior tool performance. We have intensively studied about growing diamonds. As a result, even when single-crystal diamond is grown on a diamond seed crystal including a plurality of growth sectors, a single growth sector can be selected by selecting the heating conditions for the diamond seed crystal in the heating process before reaching the growth temperature. The inventors have found that a single crystal diamond composed of

  In the method for producing a diamond composite according to the present invention, a temperature raising step for heating the diamond seed crystal is performed before the growth temperature of the single crystal diamond is reached. In this temperature raising step, methane gas and an inert gas (preferably methane gas are used). , Ethane gas and inert gas), the diamond seed crystal is heated in an atmosphere containing at least one gas. As a result, a diamond composite is obtained in which a single crystal diamond composed of a single growth sector is grown on the surface of a diamond seed crystal including a plurality of growth sectors. When the single crystal diamond separated from the diamond composite is used for a diamond tool, the tool performance can be further improved. Therefore, according to the method for manufacturing a diamond composite according to the present invention, a diamond composite having a large size and capable of improving the performance of the diamond tool can be manufactured.

  The method for producing a diamond composite may further include a step of etching the surface of the diamond seed crystal in an atmosphere containing an inert gas before the step of obtaining the diamond composite.

  Thereby, the diamond composite which can improve the performance of a diamond tool more can be manufactured.

  The method for producing a diamond composite may further include a step of polishing the surface of the diamond seed crystal at a speed of 50 μm / h or less before the step of obtaining the diamond composite.

  Thereby, the diamond composite which can improve the performance of a diamond tool further can be manufactured. The polishing rate is preferably 20 μm / h or less, and more preferably 10 μm / h or less.

  In the method for producing a diamond composite, the nitrogen concentration in the diamond seed crystal may be 0.02 atm% or less. Here, “atm%” means the atomic number density, and in the diamond seed crystal, the atomic density of nitrogen is 0.02% or less.

  When the upper limit of the nitrogen concentration in the diamond seed crystal is as high as 0.02 atm%, a step is more likely to be formed at the boundary between the growth sectors, and it is more difficult to grow single crystal diamond composed of a single growth sector. . Therefore, in such a case, the method for producing a diamond composite according to the present invention can be suitably used. The nitrogen concentration is preferably 0.005 atm% or less, more preferably 0.0005 atm% or less, and further preferably 0.0001 atm% or less.

  In the method for producing a diamond composite, the diamond seed crystal may have a width of 6 mm or more.

  When the diamond seed crystal has a large width of 6 mm or more, a plurality of growth sectors are more likely to be included, and it is more difficult to grow a single crystal diamond composed of a single growth sector. Therefore, in such a case, the method for producing a diamond composite according to the present invention can be suitably used. The width of the diamond seed crystal is preferably 8 mm or more, and more preferably 10 mm or more.

  The method for producing a single crystal diamond according to the present invention comprises a step of preparing a diamond complex in which single crystal diamond is grown on the surface of a diamond seed crystal by the method for producing a diamond complex according to the present invention. And a step of obtaining single crystal diamond by removing the diamond seed crystal from the composite.

  According to the method for producing single crystal diamond according to the present invention, single crystal diamond having a large size and comprising a single growth sector can be obtained. And tool performance can be improved more by using this single crystal diamond for a diamond tool etc. Therefore, according to the method for producing single crystal diamond according to the present invention, single crystal diamond having a large size and capable of improving the performance of the diamond tool can be produced.

  The diamond composite according to the present invention includes a diamond seed crystal including a plurality of growth sectors, and a single crystal diamond that is grown on the surface of the diamond seed crystal and includes a single growth sector.

  According to the diamond composite according to the present invention, a single crystal diamond having a large size and consisting of a single growth sector can be obtained by separating from a diamond seed crystal having a large size. Moreover, tool performance can be further improved by using this single crystal diamond for a diamond tool or the like. Therefore, according to the diamond composite according to the present invention, a diamond composite having a large size and capable of improving the performance of the diamond tool can be provided.

  In the diamond composite, the nitrogen concentration in the diamond seed crystal may be 0.02 atm% or less.

  As described above, when the upper limit of the nitrogen concentration in the diamond seed crystal is as high as 0.02 atm% or less, it is difficult to obtain single crystal diamond composed of a single growth sector. Therefore, in such a case, the diamond composite according to the present invention can be suitably used. The nitrogen concentration is preferably 0.005 atm% or less, more preferably 0.0005 atm% or less, and further preferably 0.0001 atm% or less. .

  In the above diamond composite, the diamond seed crystal may have a width of 6 mm or more.

  As described above, when the diamond seed crystal has a large width of 6 mm or more, it is difficult to obtain a single crystal diamond composed of a single growth sector. Therefore, in such a case, the diamond composite according to the present invention can be suitably used. The width of the diamond seed crystal is preferably 8 mm or more, and more preferably 10 mm or more.

  The single crystal diamond according to the present invention can be obtained by removing the diamond seed crystal from the diamond composite according to the present invention.

  Since the single crystal diamond according to the present invention is a single crystal diamond having a large size and a single growth sector as described above, the tool performance can be further improved by using this for a diamond tool or the like. . Therefore, according to the single crystal diamond according to the present invention, a single crystal diamond having a large size and capable of improving the performance of the diamond tool can be provided.

  The diamond tool according to the present invention comprises the single crystal diamond according to the present invention, which can improve the performance of the diamond tool. Therefore, according to the diamond tool according to the present invention, a diamond tool with improved tool performance can be provided.

  As is apparent from the above description, the diamond composite and single crystal diamond according to the present invention provide a diamond composite and single crystal diamond that are large in size and can improve the performance of the diamond tool. can do. Further, according to the method for producing a diamond composite and single crystal diamond according to the present invention, it is possible to produce a diamond composite and single crystal diamond which are large in size and can improve the performance of a diamond tool. . Moreover, according to the diamond tool according to the present invention, a diamond tool with improved tool performance can be provided.

It is the schematic which shows the structure of the diamond tool which concerns on this Embodiment. It is the schematic which shows the diamond composite_body | complex and single crystal diamond which concern on this Embodiment. It is a flowchart which shows schematically the manufacturing method of the diamond composite_body | complex and single crystal diamond which concern on this Embodiment. It is the schematic for demonstrating the process (S10) in the manufacturing method of the diamond composite_body | complex which concerns on this Embodiment. It is the schematic which shows the cross section which follows the line segment VV in FIG. It is another schematic diagram for demonstrating the process (S10) in the manufacturing method of the diamond composite_body | complex which concerns on this Embodiment. It is the schematic for demonstrating the process (S40) in the manufacturing method of the diamond composite_body | complex which concerns on this Embodiment. It is the schematic for demonstrating the process (S50) in the manufacturing method of the diamond composite_body | complex which concerns on this Embodiment. It is the schematic for demonstrating the process (S60) in the manufacturing method of the single crystal diamond which concerns on this Embodiment.

  Next, embodiments of the present invention will be described with reference to the drawings. In the following drawings, the same or corresponding parts are denoted by the same reference numerals, and description thereof will not be repeated. In the present specification, the individual orientation is indicated by [], the collective orientation is indicated by <>, the individual plane is indicated by (), and the aggregate plane is indicated by {}.

  First, a diamond cutting tool 1 will be described as an example of a diamond tool according to an embodiment of the present invention. Referring to FIG. 1, a diamond tool 1 according to the present embodiment mainly includes a base metal 2, a brazing layer 3, a metallized layer 4, and a single crystal diamond 10.

  Single crystal diamond 10 is fixed to base metal 2 via brazing layer 3 and metallization layer 4. Single crystal diamond 10 includes rake face 10b and flank face 10c, and cutting edge 10d is formed at the contact portion between rake face 10b and flank face 10c. Further, since the single crystal diamond 10 is a single crystal diamond according to the present embodiment described later, the diamond tool 1 has improved tool performance.

  The diamond tool of the present invention is not limited to the diamond tool 1 described above, and may be another cutting tool (not shown) such as a drill or an end mill. ) Also in these cutting tools and wear resistant tools, the tool performance can be improved by providing the single crystal diamond 10 in the same manner as the diamond cutting tool 1 described above.

  Next, the diamond composite 30 and the single crystal diamond 10 according to the present embodiment will be described. Referring to FIG. 2, diamond composite 30 according to the present embodiment includes diamond seed crystal 20 and single crystal diamond 10 grown on surface 20 a of diamond seed crystal 20. Therefore, single crystal diamond 10 according to the present embodiment is obtained by removing diamond seed crystal 20 from diamond composite 30. The single crystal diamond 10 is used as a material for a diamond tool such as the diamond tool 1 as described above.

  The diamond seed crystal 20 is manufactured by a high-temperature and high-pressure synthesis method. The diamond seed crystal 20 includes a {001} growth sector 21 and a {111} growth sector 22 formed so as to sandwich the {001} growth sector 21. Further, the surface 20a of the diamond seed crystal 20 includes a surface 21a composed of a {001} plane and a surface 22a composed of a {111} plane. Thus, the diamond seed crystal 20 includes a plurality of growth sectors. Note that the number of growth sectors in the diamond seed crystal 20 is not particularly limited, and may be two as shown in FIG. 2 or more. For example, the diamond seed crystal 20 may include a {113} growth sector or a {011} growth sector between the {001} growth sector 21 and the {111} growth sector 22. Good.

  Here, the “growth sector” means a crystal region having the same growth direction in the diamond crystal and, as a result, a region where impurities, defect concentrations, and the like are substantially the same. The {001} growth sector 21 is a region grown in the <001> direction, and the {111} growth sector 22 is a region grown in the <111> direction. Further, the polishing rate and the etching rate are different between different growth sectors. Therefore, for example, when the surface 20a of the diamond seed crystal 20 is polished or etched, a step is formed at the boundary between the surface 21a and the surface 22a. Also, since different growth sectors have different impurities (for example, nitrogen atoms) and defect concentrations, different growth sectors are determined by cathodoluminescence (CL) measurement or photoluminescence (PL) measurement. Can be distinguished. In addition, since there is distortion at the boundary between different growth sectors, the boundary can be confirmed by, for example, a polarization image.

  Unless specifically controlled, the diamond seed crystal 20 is naturally introduced (doped) with impurity atoms such as nitrogen (N) atoms. In addition, the amount of nitrogen introduced can be reduced by controlling the synthesis conditions. The nitrogen concentration in the diamond seed crystal 20 is 0.02 atm% or less, preferably 0.005 atm% or less, more preferably 0.0005 atm% or less, and further preferably 0.0001 atm% or less. Moreover, the width W of the diamond seed crystal 20 is 6 mm or more, preferably 8 mm or more, and more preferably 10 mm or more.

  The single crystal diamond 10 is grown on the surface 20a of the diamond seed crystal 20 by a vapor phase synthesis method such as a microwave excitation plasma CVD method. The single crystal diamond 10 is composed of a single growth sector, and more specifically, is composed of only the {001} growth sector. Similarly to the diamond seed crystal 20, the width W of the single crystal diamond 10 is 6 mm or more, preferably 8 mm or more, and more preferably 10 mm or more.

  As described above, according to the diamond composite 30 according to the present embodiment, by removing the diamond seed crystal 20 from the diamond composite 30, the size is large (6 mm or more) and a single growth sector can be obtained. A single crystal diamond 10 can be obtained. The tool performance can be further improved by using the single crystal diamond 10 for a tool such as the diamond tool 1. As described above, the diamond composite 30 and the single crystal diamond 10 according to the present embodiment are large in size and can improve the performance of the diamond tool.

  Next, a method for producing a diamond composite and single crystal diamond according to the present embodiment will be described. Referring to FIG. 3, in the method for manufacturing a diamond composite according to the present embodiment, steps (S 10) to (S 50) are sequentially performed to manufacture diamond composite 30. Further, in the method for producing single crystal diamond according to the present embodiment, the single crystal diamond 10 is produced by further carrying out step (S60) in addition to steps (S10) to (S50).

  In the method for manufacturing a diamond composite according to the present embodiment, first, a diamond seed crystal preparation step is performed as a step (S10). In this step (S10), referring to FIG. 4, first, a diamond crystal body 20A (type: Ib) manufactured by a high-temperature high-pressure synthesis method is prepared. On the surface of the diamond crystal body 20, a surface 21a composed of a {001} plane and a surface 22a composed of a {111} plane are formed.

  FIG. 5 is a sectional view taken along line V-V of diamond crystal body 20A shown in FIG. Referring to FIG. 5, diamond crystal body 20 </ b> A includes {001} growth sector 21 and {111} growth sector 22. {001} growth sector 21 includes surface 21a, and {111} growth sector 22 includes surface 22a. The {001} growth sector 21 is formed so as to expand toward the surface 21a, and the {111} growth sector 22 is formed so as to expand toward the surface 22a.

  Next, the diamond crystal body 20A is cut as shown by the dotted line in FIG. Thereby, as shown in FIG. 6, the diamond seed crystal 20 including the {001} growing sector 21 and the {111} growing sector 22 is obtained. By cutting out a diamond seed crystal including a plurality of growth sectors in this way, a large seed crystal can be obtained. The diamond seed crystal 20 is used in a state where both ends are appropriately cut off.

  In this step (S10), it is preferable to prepare a diamond seed crystal 20 having a nitrogen concentration of 0.02 atm% or less. Further, the nitrogen concentration of the diamond seed crystal 20 is more preferably 0.005 atm% or less, further preferably 0.0005 atm% or less, and further preferably 0.0001 atm% or less.

  In this step (S10), it is preferable to prepare a diamond seed crystal 20 having a width W of 6 mm or more. The width W of the diamond seed crystal 20 is more preferably 8 mm or more, and further preferably 10 mm or more.

  Next, a polishing process is performed as a process (S20). In this step (S20), referring to FIG. 6, surface 20a and back surface 20b of diamond seed crystal 20 are polished by, for example, mechanical polishing using a polishing disk to which diamond abrasive grains are fixed. In this step (S20), the polishing rate is preferably 50 μm / h or less, more preferably 20 μm / h or less, and further preferably 10 μm / h or less.

  The low-speed polishing (polishing with a polishing rate of 50 μm / h or less) is preferably performed in combination with high-speed polishing (polishing with a polishing rate exceeding 50 μm / h). Thereby, the polishing time can be further shortened. The low-speed polishing is preferably performed for a period of 5 minutes to 30 minutes.

Next, an etching process is implemented as process (S30). In this step (S30), referring to FIG. 6, surface 20a and back surface 20b of diamond seed crystal 20 are etched in an atmosphere containing an inert gas such as argon (Ar) gas. The inert gas is not limited to argon gas, and may be other rare gas such as helium (He) gas or xenon (Xe). In addition, the etching method of the diamond seed crystal 20 is not limited to the above method, and for example, reactive ion etching (RIE) using oxygen (O ₂ ) gas and carbon tetrafluoride (CF ₄ ) gas. May be.

  Next, an ion implantation step is performed as a step (S40). In this step (S40), referring to FIG. 7, carbon (C), nitrogen (N), silicon (Si), phosphorus (P) or sulfur (S) is implanted into diamond seed crystal 20 from the surface 20a side. Is done. Thereby, the conductive layer 40 is formed in a region including the surface 20a.

  Next, an epitaxial growth step is performed as a step (S50). In this step (S50), referring to FIG. 8, epitaxial growth layer 50 (single crystal) is formed on surface 20a (on conductive layer 40) of diamond seed crystal 20 by a vapor phase synthesis method such as a microwave-excited plasma CVD method. Diamond) grows. In this step (S50), a temperature raising step (S51) and a growth step (S52) described below are sequentially performed.

First, in the temperature raising step (S51), before reaching the growth temperature (800 to 1100 ° C.) of the single crystal diamond, at least one of hydrogen (H ₂ ) gas and methane gas and argon gas (inert gas). The diamond seed crystal 20 is heated in an atmosphere containing. More specifically, the diamond seed crystal 20 may be heated in an atmosphere containing hydrogen gas and methane gas, the diamond seed crystal 20 may be heated in an atmosphere containing hydrogen gas and argon gas, or hydrogen. The diamond seed crystal 20 may be heated in an atmosphere containing gas, methane gas, and argon gas.

  In this step (S51), the flow rate of methane gas with respect to the flow rate of hydrogen gas is preferably 0.01 volume% or more and 12 volume% or less, more preferably 0.05 volume% or more and 5 volume% or less. The flow rate of argon gas with respect to the flow rate of hydrogen gas is preferably 1% by volume or more and 99% by volume or less, and more preferably 20% by volume or more and 80% by volume or less.

  This step (S51) is a step for raising the temperature of the substrate (diamond seed crystal 20) before the growth step (S52) is started. That is, this step (S51) corresponds to the time from the start of power input to the start of the growth step (S52) at a constant temperature. Further, the time during which the temperature is excessively increased and the temperature is decreased is also included in this step (S51). In this step (S51), at least 5% or more of the total time of step (S51) (preferably 15% or more, more preferably 30% or more, even more preferably 70%) The diamond seed crystal 20 is heated in the gas atmosphere.

  In this step (S51), the inert gas is not limited to argon gas, and may be other rare gas such as helium gas or xenon gas.

  Next, in the growth step (S52), the diamond seed crystal 20 is heated in an atmosphere containing hydrogen gas, methane gas, and nitrogen gas. The heating temperature is set to 800 to 1100 ° C., and the pressure is set to 10.7 to 14.7 kPa. Thereby, an epitaxial growth layer 50 (single crystal diamond) grows on the surface 20 a of the diamond seed crystal 20. In this step (S52), the flow rate of methane gas with respect to the flow rate of hydrogen gas is 5% by volume or more and 20% by volume or less, and the flow rate of nitrogen gas with respect to the flow rate of hydrogen gas is 0.1% by volume or more and 10% by volume or less. It is. Thus, the ratio of the flow rate of methane gas to the flow rate of hydrogen gas is smaller in the temperature raising step (S51) than in the growth step (S52). The diamond composite 30 is manufactured by carrying out the steps (S10) to (S50) as described above, and the method for manufacturing the diamond composite according to the present embodiment is completed.

  Next, a separation step is performed as a step (S60). In this step (S60), referring to FIG. 9, diamond layer 20 and epitaxial growth layer 50 are separated by electrochemically etching conductive layer 40. In this way, single crystal diamond 10 (epitaxial growth layer 50) is obtained.

  Further, this step (S60) is not limited to the case where the conductive layer 40 is etched electrochemically. For example, the conductive layer 40 is irradiated with laser light from the surface 20a side to be condensed on the conductive layer 40 and absorbed to absorb the energy. Layer 40 may be removed. Further, the diamond seed crystal 20 and the epitaxial growth layer 50 may be cut and separated by irradiating laser light from the side surface side. In this case, the conductive layer 40 is not necessarily formed. Further, in this case, the cutting margin becomes large, but the single crystal diamond 10 composed of a single growth sector can be obtained. As described above, the steps (S10) to (S60) are performed to manufacture the single crystal diamond 10, and the method for manufacturing the single crystal diamond according to the present embodiment is completed.

  As described above, in the method for producing a diamond composite and single crystal diamond according to the present embodiment, the diamond seed crystal 20 is heated before reaching the growth temperature (800 to 1100 ° C.) of the single crystal diamond ( S51) is performed, and in the temperature raising step (S51), the diamond seed crystal 20 is heated in an atmosphere containing at least one of methane gas and argon gas. As a result, a diamond composite 30 is obtained in which the single crystal diamond 10 composed of a single growth sector is grown on the diamond seed crystal 20 including a plurality of growth sectors, and the diamond seed crystal 20 is removed from the diamond composite 30. Thus, the single crystal diamond 10 is obtained. The tool performance can be further improved by using the single crystal diamond 10 for a tool such as the diamond tool 1. Therefore, according to the method for producing a diamond composite and single crystal diamond according to the present embodiment, diamond composite 30 and single crystal diamond 10 that are large in size and capable of improving the performance of the diamond tool are produced. be able to.

  On the other hand, in the method that is not the method for producing the diamond composite and single crystal diamond according to the present embodiment, a minute growth sector is formed in the epitaxial growth layer due to the boundary portion of the growth sector in diamond seed crystal 20. This can be confirmed by evaluating CL or PL, or by evaluating a polarization image, and can be more clearly confirmed by evaluating the tool performance.

  Further, when the size of the grown crystal is large, for example, when the longest size of the tool (maximum length of the region that can be used as a tool) is 6 mm or more (preferably 8 mm or more, more preferably 10 mm or more), Since the diamond seed crystal 20 is likely to include a plurality of growth sectors, it is more difficult to grow a single crystal diamond composed of a single growth sector. Therefore, in such a case, the method for producing the diamond composite and single crystal diamond according to the present embodiment can be particularly preferably used.

Experiments were conducted to confirm the effect of the present invention on the performance improvement of diamond tools using single crystal diamond.
(Production of single crystal diamond)
First, the single crystal diamond 10 was manufactured using the method for manufacturing a single crystal diamond according to the present embodiment (see FIGS. 3 to 9). In the step (S10), the width W1 of the diamond crystal body 20A was about 8 mm, and the width W2 of the surface 21a was about 5 mm (see FIG. 4). Then, the diamond seed crystal 20 was cut out so as to include the {001} growth sector 21 and the {111} growth sector 22 (see FIGS. 5 and 6).

  In the step (S20), mechanical polishing (condition (1) or (2)) with a polishing disk to which diamond abrasive grains are fixed, or a machine at a polishing rate of 50 μm / h or less with a polishing disk to which diamond abrasive grains are fixed. The surface 20a and the back surface 20b of the diamond seed crystal 20 were polished by polishing (low speed mechanical polishing, condition (3)).

  In the step (S30), diamond seed crystals are obtained by RIE (condition (1)) using oxygen gas and carbon tetrafluoride gas, or by etching in an atmosphere containing argon gas (condition (2) or (3)). The front surface 20a and the back surface 20b of 20 were etched.

In the step (S40), carbon, silicon, or phosphorus ions were implanted into the diamond seed crystal 20 at an energy of 300 to 350 keV and a dose of 5 × 10 ^{15 to} 5 × 10 ¹⁷ pieces / cm ² , thereby forming the conductive layer 40. (See FIG. 7). The type of the implanted element did not greatly affect the evaluation results described later.

  In the step (S51), an atmosphere introduced with hydrogen gas (condition (4)), an atmosphere introduced with hydrogen gas and nitrogen gas (condition (5)), and an atmosphere introduced with hydrogen gas and oxygen gas (condition ( 6)), an atmosphere introduced with hydrogen gas and argon gas (condition (7)), an atmosphere introduced with hydrogen gas and methane gas (condition (8)) or an atmosphere introduced with hydrogen gas, methane gas and argon gas (condition (7)) In the condition (9)), the diamond seed crystal 20 was heated to a steady temperature (800 to 1100 ° C.) (Example: Conditions (7) to (9), Comparative Example: Conditions (4) to (6)). In the growth step (S52), an epitaxial growth layer 50 (single crystal diamond) having a thickness of about 0.5 mm was grown in an atmosphere into which hydrogen gas, methane gas, and nitrogen gas were introduced. Tables 1 and 2 show the respective processing conditions in the above examples and comparative examples. In the growth step (S52), the epitaxial growth layer 50 was formed within the range of general synthesis conditions that are usually performed.

(Observation of single crystal diamond)
A predetermined etching treatment (for example, RIE in an atmosphere containing oxygen gas, hydrogen plasma, mixed plasma of oxygen and hydrogen, mixed plasma of nitrogen and hydrogen, etc.) is performed on the surface of the single crystal diamond of the example and the comparative example, and then The etched surface was observed. As a result, in the comparative example, streaks were observed due to the level difference on the surface, whereas in the example, no streaks were observed.
(Performance evaluation of diamond tools)
A diamond cutting tool was prepared using the single crystal diamond of the example and the comparative example, and the work material was processed using the diamond cutting tool. Table 3 shows the results of the above machining experiment. When no cutting marks (streaks formed on the mirrored cutting surface) occur in the machined material after processing, it is indicated as “◯”. In addition, when a cutting mark is generated, “x” is written. In addition, the notation “−” indicates a case where the above processing experiment was not performed.

  As apparent from Table 3, when the conditions (4) to (6) were adopted in the temperature raising step (S51), cutting marks were generated on the work material, whereas conditions (7) to (9 ) Was used, no cutting marks were generated on the work material. Further, when the condition (1) is adopted in the polishing step (S20) and the etching step (S30), a cutting mark is generated on the work material regardless of the nitrogen concentration of the diamond seed crystal 20, whereas the condition ( In 2), no cutting trace occurs when the nitrogen concentration is 0.0005 atm% or less, and no cutting trace occurs when the nitrogen concentration is 0.02 atm% or less in condition (3). It was. From the above experimental results, by heating the diamond seed crystal 20 in an atmosphere containing at least one of methane gas and inert gas in the temperature raising step (S51), the tool performance consists of a single growth sector. It has been found that excellent single crystal diamond can be obtained.

  It should be understood that the embodiments and examples disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  Diamond composite of the present invention, single crystal diamond and production method thereof, and diamond tool, diamond composite, single crystal diamond and production method thereof, and single crystal are required to improve the performance of diamond tool It is particularly advantageously applied in a diamond tool comprising diamond.

  1 diamond tool, 2 base metal, 3 brazing layer, 4 metallized layer, 10 single crystal diamond, 10b rake face, 10c flank face, 10d cutting edge, 20A diamond crystal, 20 diamond seed crystal, 20a, 21a, 22a surface 20b Back surface, 21 {001} growth sector, 22 {111} growth sector, 30 diamond composite, 40 conductive layer, 50 epitaxial growth layer, W, W1, W2 width.

Claims (9)

A step of preparing a diamond seed crystal viewing contains a multiple of growth sectors, and the nitrogen concentration is less than or equal to 0.02atm%,
Polishing the surface of the diamond seed crystal at a speed of 50 μm / h or less using a polishing machine to which diamond abrasive grains are fixed;
Etching the surface in a first atmosphere containing a first inert gas after the polishing step;
After the etching step, a step of forming a conductive layer by ion-implanting at least one of carbon, silicon, and phosphorus ions into the surface;
After the step of forming the conductive layer, a step of growing a single crystal diamond on the surface by a vapor phase synthesis method to obtain a diamond composite,
The step of obtaining the diamond composite includes a heating step of heating the diamond seed crystal before reaching the growth temperature of the single crystal diamond,
In the temperature raising step, the diamond seed crystal is heated in a second atmosphere containing at least one of methane gas and a second inert gas ,
The ion implantation energy is 350 keV or less, and the dose amount of the ion implantation is 5 × 10 ¹⁵ pieces / cm ² or more and 5 × 10 ¹⁷ pieces / cm ² or less . The first inert gas and the second inert gas are argon gas,
The second atmosphere further includes hydrogen gas,
The method for producing a diamond composite according to claim 1, wherein the ion implantation energy is 300 keV or more. Preparing a diamond seed crystal including a plurality of growth sectors and having a nitrogen concentration of 0.005 atm% or less;
Polishing the surface of the diamond seed crystal using a polishing machine to which diamond abrasive grains are fixed;
Etching the surface in a first atmosphere containing a first inert gas after the polishing step;
A step of forming a conductive layer by ion-implanting at least one of carbon, silicon, and phosphorus ions into the surface after the etching step;
After the step of forming the conductive layer, a step of growing a single crystal diamond on the surface by a vapor phase synthesis method to obtain a diamond composite,
The step of obtaining the diamond composite includes a heating step of heating the diamond seed crystal before reaching the growth temperature of the single crystal diamond,
In the temperature raising step, the diamond seed crystal is heated in a second atmosphere containing at least one of methane gas and a second inert gas,
The ion implantation energy is 350 keV or less, and the ion implantation dose is 5 × 10 5. ¹⁵ Piece / cm ² 5 × 10 or more ¹⁷ Piece / cm ² A method for producing a diamond composite, which is as follows. The first inert gas and the second inert gas are argon gas,
The second atmosphere further includes hydrogen gas,
The method for producing a diamond composite according to claim 3, wherein the ion implantation energy is 300 keV or more.   The method for producing a diamond composite according to any one of claims 1 to 4, wherein the diamond seed crystal has a width of 6 mm or more. The method for manufacturing a diamond composite according to any one of claims 1 to 5, a step of preparing a diamond composite single crystal diamond is grown on said surface,
And obtaining the single crystal diamond by removing the diamond seed crystal from the diamond composite. A diamond seed containing multiple growth sectors;
Growing on the surface of the diamond seed crystal, and comprising a single crystal diamond consisting of a single growth sector,
The diamond seed crystal is a diamond composite having a conductive layer on the surface .   The diamond composite according to claim 7, wherein a nitrogen concentration in the diamond seed crystal is 0.02 atm% or less.   The diamond composite according to claim 7 or 8, wherein the diamond seed crystal has a width of 6 mm or more.

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