JP7681850B2 - Diamond anvil and its manufacturing method and use method - Google Patents

Description

The present invention relates to a diamond anvil for applying high pressure to a sample.

To measure the physical properties (electrical resistance, X-ray scattering spectrum, etc.) of a sample under ultra-high pressure conditions, a high pressure is applied to the sample using a diamond anvil. A diamond anvil is a roughly conical body with a small tip surface, and is obtained, for example, by cutting and polishing a natural diamond.

A pair of diamond anvils like this are positioned so that their tip faces face each other, and with a sample sandwiched between the tip faces, high pressure is applied to the pair of diamond anvils as they are pressed against each other. In this way, ultra-high pressure (for example, 150 GPa to 200 GPa) is applied to the sample. By measuring the physical properties of the sample while it is being subjected to ultra-high pressure in this way, it is possible to measure the physical properties of the sample under ultra-high pressure conditions and advance the search for new functions for the sample.

For example, when hydrogen sulfide solidified with liquid nitrogen was used as a sample and subjected to ultra-high pressure of about 150 GPa as described above and its electrical resistance was measured as a physical property, it was discovered that hydrogen sulfide exhibits a high superconducting transition temperature exceeding absolute temperature 200 K.

Diamond anvils are described, for example, in Patent Document 1.

JP 2018-128286 A

As described above, when a sample (e.g., solidified hydrogen sulfide) is subjected to a pressure of about 150 GPa using a diamond anvil and then X-rays are continuously irradiated onto the sample for a long period of time (e.g., about 12 hours) in order to measure its physical properties (e.g., X-ray scattering spectrum), there is a problem that the diamond anvil may be damaged by the effects of the X-rays.

The present invention was made to solve this problem. That is, the object of the present invention is to prevent damage to the diamond anvil due to the influence of X-rays when the diamond anvil is irradiated with X-rays for a long period of time while applying ultra-high pressure (e.g., pressure of about 150 GPa) to the sample by the diamond anvil.

In order to achieve the above object, according to the present invention, there is provided a diamond anvil for applying pressure to a sample, comprising:
A diamond anvil is provided having a diamond body and a CVD diamond film formed on a surface of the body.

According to the present invention, there is also provided a method for manufacturing a diamond anvil for applying pressure to a sample, the method comprising the steps of:
(A) Prepare a diamond body;
(B) A method for manufacturing a diamond anvil is provided, which comprises forming a CVD diamond film on the surface of the body by chemical vapor deposition to obtain a diamond anvil having the body and the CVD diamond film.

According to the present invention, a CVD diamond film is formed on the surface of the diamond body. This makes it possible to prevent damage to the diamond anvil when X-rays are irradiated onto the sample and diamond anvil for a long period of time while ultra-high pressure is applied to the sample using the diamond anvil.

FIG. 1 is a side view showing an example of a diamond anvil to which the present invention can be applied. FIG. 1 is an explanatory diagram of a case where a sample is pressurized using a pair of diamond anvils. This is an actual image of a diamond anvil in which a crack has occurred, viewed from its tip face side. FIG. 1 is a side view showing a configuration of a diamond anvil according to an embodiment of the present invention. This is a view taken along the line 4B-4B in FIG. 4A. FIG. 2 is a schematic diagram of an example of a crystal structure in which diamond crystals are oxygen-terminated on the surface of a CVD diamond film. FIG. 2 is a schematic diagram of an example of a crystal structure in which diamond crystals are hydrogen-terminated on the surface of a CVD diamond film. 1 is a flowchart showing a method of manufacturing a diamond anvil according to an embodiment of the present invention. 1 is an image of the tip face of a diamond anvil according to an embodiment, observed from the back side before X-ray irradiation. 1 is an image of the tip face of a diamond anvil according to an embodiment, observed from the back side after being irradiated with X-rays. 1 is an image of the tip face of a diamond anvil according to a comparative example, observed from the back side before X-ray irradiation. 1 is an image of the tip face of a diamond anvil according to a comparative example, observed from the back side after being irradiated with X-rays. FIG. 4B shows the case where a mark is provided on the surface of the diamond anvil.

The embodiment of the present invention will be described with reference to the drawings. Note that common parts in each drawing are given the same reference numerals, and duplicated explanations will be omitted.

(Diamond anvil to which the present invention can be applied)
1 is a side view showing an example of a diamond anvil 10 to which the present invention can be applied. The diamond anvil 10 is for applying high pressure to a sample. The diamond anvil 10 has a tip surface 11, an inclined surface 12 on the tip surface 11 side, and a base portion 13 located on the opposite side to the tip surface 11. The tip surface 11 is a surface (also called a curette) on which a sample is placed when the sample is pressurized by the diamond anvil 10. The base portion 13 has a bottom surface 15 facing the opposite side to the tip surface 11.

The diamond anvil 10 has a shape in which the cross-sectional area gradually increases from the tip surface 11 to the base portion 13. In this case, the inclined surface 12 extends from the tip surface 11 to the base portion 13 of the diamond anvil 10 in a direction inclined (for example, greater than 45 degrees) relative to the central axis C of the diamond anvil 10, moving away from the central axis C, and also extends in the circumferential direction around the central axis C to complete one revolution.

The above cross-sectional area is the area of a cross section of an imaginary plane perpendicular to the central axis C of the diamond anvil 10. The central axis C faces from the base 13 toward the tip surface 11. The tip surface 11 and the bottom surface 15 may be planes perpendicular to the central axis C.

In the diamond anvil 10, the shape of the portion from the tip surface 11 to the boundary between the inclined surface 12 and the base 13 may be approximately conical, for example, a polygonal pyramid with the tip of the pyramid cut off (a regular hexagonal pyramid in one example). The tip surface 11 may be a surface having a dimension (for example, a diameter) of about 10 μm or more and 1 mm or less, but is not limited to this dimension.

Figure 2 is an explanatory diagram of the case where a pair of the diamond anvils 10 described above are used to pressurize a sample. In Figure 2, each diamond anvil 10 is shown as viewed from the side, and the gasket 14 described below is shown as a cross section taken along a plane including the central axis C of the diamond anvil 10.

As shown in FIG. 2, a pair of diamond anvils 10 are arranged so that their tip surfaces 11 face each other, and a sample is placed between the tip surfaces 11. At this time, the sample (not shown) may be placed using a gasket 14. The gasket 14 is a plate-shaped sealing member with a through hole formed in the center. With the sample placed in this through hole, the gasket 14 is placed between both tip surfaces 11 together with the sample. In this state, a load is applied to the bottom surface 15 of each diamond anvil 10 toward the tip surface 11 of the diamond anvil 10 using a pressure mechanism (not shown). As a result, the sample is sandwiched between the tip surfaces 11 of the pair of diamond anvils 10, and ultra-high pressure (for example, 150 GPa to 200 GPa) is applied to the sample. At this time, the gasket 14 is in close contact with the diamond anvil 10 even when it is deformed, thereby preventing the sample from coming off the tip surface 11.

Each diamond anvil 10 in Figure 2 is obtained by cutting a natural diamond and polishing the surface of the cut diamond. When such a diamond anvil 10 is used to apply ultra-high pressure (150 GPa to 200 GPa) to a sample (e.g., solidified hydrogen sulfide) as shown in Figure 2 above, and X-rays are continuously irradiated onto the sample for a long period of time (e.g., about 12 hours) to measure its physical properties (e.g., X-ray scattering spectrum), the diamond anvil 10 will be damaged by the effects of the X-rays.

A diamond anvil 10 damaged in this manner is shown in Figures 3A to 3D. Each of Figures 3A to 3D is an actual image of the diamond anvil 10 viewed from its tip surface 11. As shown in Figures 3A to 3D, the diamond anvil 10 has numerous cracks and is damaged. Note that in Figures 3A to 3D, the diamond anvil 10 appears opaque due to the influence of the illumination light.

(Configuration of the embodiment of the present invention)
The diamond anvil 20 according to the embodiment of the present invention for suppressing such damage will be described. Fig. 4A is a side view showing the configuration of the diamond anvil 20 according to the embodiment of the present invention. Fig. 4B is a view taken along the line 4B-4B of Fig. 4A.

The diamond anvil 20 according to this embodiment is formed by forming a CVD diamond film 21 on the surface of the diamond anvil 10 described above. In other words, the diamond anvil 20 according to this embodiment is formed by forming a CVD diamond film 21 on the surface of the diamond anvil 10 described above that is not being used to pressurize the sample. In this embodiment, the surface of the CVD diamond film 21 is not polished, so there are few or almost no polishing marks (such as extremely small cracks on the nanometer order, which will be described later) on the surface.

According to this embodiment, a CVD diamond film 21 may be formed as a synthetic (i.e., artificial) diamond film on at least the entire tip surface 11 (the tip surface corresponding to the location where the sample is placed) on the surface of the main body 10. In one example, as shown in FIG. 3A, a CVD diamond film 21 may be formed on the tip surface 11 and the inclined surface 12 (e.g., the entire tip surface 11 and the inclined surface 12) on the surface of the main body 10. The thickness of the CVD diamond film 21 may be, for example, 10 nm or more and 100 nm or less (40 nm or less in one example). In this case, the upper limit of the thickness of the CVD diamond film 21 may be about several hundred nm.

The surface of the portion of the CVD diamond film 21 formed on the tip surface 11 becomes the new tip surface 21a of the diamond anvil 20. In this case, the surface of the portion of the CVD diamond film 21 formed on the inclined surface 12 becomes the new inclined surface 21b of the diamond anvil 20. Like the inclined surface 12, the inclined surface 21b extends from the tip surface 21a to the base 13 of the diamond anvil 20 in a direction inclined (for example, greater than 45 degrees) relative to the central axis C of the diamond anvil 20, moving away from the central axis C, and extends in a circumferential direction around the central axis C to complete one revolution. The diamond anvil 20 has the same shape as the diamond anvil 10 described above. That is, in the diamond anvil 20, the shape of the portion from the tip surface 21a to the boundary between the inclined surface 21b and the base 13 may be approximately conical, for example, a prefixed pyramid shape obtained by cutting the tip of a polygonal pyramid (for example, a regular hexagonal pyramid).

The diamond crystals constituting the surface (e.g., the entire surface) of the CVD diamond film 21 may be oxygen-terminated. That is, in the diamond crystals constituting the surface of the CVD diamond film 21, oxygen atoms may be bonded to each dangling bond of the carbon atom.

Alternatively, the diamond crystals constituting the surface (e.g., the entire surface) of the CVD diamond film 21 may be hydrogen-terminated. That is, in the diamond crystals constituting the surface of the CVD diamond film 21, a hydrogen atom may be bonded to each dangling bond of a carbon atom.

Figures 5A and 5B are schematic diagrams of crystal structure examples in which diamond crystals are oxygen-terminated on the surface of CVD diamond film 21. In Figures 5A and 5B, each open circle represents a carbon atom, and each shaded circle represents an oxygen atom. In Figures 5A and 5B, the upper side is the surface side of CVD diamond film 21. As in the case of Figure 5B, cross-linking bonds may be formed by oxygen atoms bonded to dangling bonds of diamond crystals that make up the surface of CVD diamond film 21.

Figures 6A and 6B are schematic diagrams of examples of crystal structures in which diamond crystals are hydrogen-terminated on the surface of the CVD diamond film 21. In Figures 6A and 6B, the larger white circles represent carbon atoms, and the smaller white circles represent hydrogen atoms. In Figures 6A and 6B, the upper side represents the surface side of the CVD diamond film 21.

Note that the specific form in which the diamond crystals on the surface of the CVD diamond film 21 are oxygen-terminated or hydrogen-terminated is not limited to the examples shown in Figures 5A to 6B.

(Manufacturing method of diamond anvils)
7 is a flow chart showing a method for manufacturing the diamond anvil 20 according to an embodiment of the present invention. The manufacturing method according to this embodiment includes steps S1 to S4.

In step S1, a diamond body 10 is prepared. For example, in step S1, the above-mentioned diamond anvil 10 shown in FIG. 1 is prepared as the diamond anvil body 10. In one example, the body 10 prepared in step S1 is obtained by cutting a diamond (e.g., a natural single crystal diamond) into a predetermined shape (e.g., an approximately conical shape) and polishing the surface of the cut diamond of that shape.

In step S2, hydrogen plasma is brought into contact with the surface of the main body 10 (e.g., the entire tip surface 11 and the entire inclined surface 12). Step S2 may be performed as follows. The main body 10 is placed in a vacuum chamber. Next, the inside of the vacuum chamber is evacuated with a vacuum pump to create a vacuum inside the vacuum chamber. Thereafter, hydrogen gas is introduced into the vacuum state of the chamber to generate hydrogen plasma. This hydrogen plasma may be generated, for example, by introducing microwaves into the vacuum chamber.

The hydrogen plasma thus generated is brought into contact with the surface of the main body 10 (for example, by irradiating the surface of the main body 10 with hydrogen plasma), thereby cleaning the surface. This makes it possible to remove defective parts on the surface of the main body 10. Here, the defective parts may be, for example, parts with poor crystallinity, parts where hydrogen or oxygen is bonded, or fine cracks. In one example of the processing conditions for step S2, the energy (strength) of the microwaves introduced into the chamber is about 750 W, the flow rate and pressure of the hydrogen gas introduced into the chamber are about 300 sccm and about 35 torr, respectively, the processing temperature (surface temperature of the main body 10) is about 800° C., and the processing time is about 5 minutes. However, the processing conditions for step S2 are not limited to these.

After step S2 is completed, the hydrogen plasma generation intensity is reduced, for example by reducing the microwave strength (strength per unit area) described above. This state of reduced hydrogen plasma generation intensity is maintained until step S3, described below, is completed. That is, until step S3 is completed, hydrogen gas and microwaves are continued to be introduced into the vacuum chamber, maintaining a hydrogen plasma atmosphere inside the vacuum chamber. The vacuum state created by the reduced pressure inside the vacuum chamber is also maintained until step S3 is completed.

In step S3, a CVD diamond film 21 is formed on the surface of the main body 10 by a chemical vapor deposition (CVD) method. In this embodiment, in step S3, a CVD diamond film 21 is formed on the surface of the main body 10 by a CVD method in an area including at least the entire tip surface 11 (e.g., the entire tip surface 11 and the entire inclined surface 12).

Step S3 may be performed as follows. Hydrocarbon gas (e.g., methane gas) is further introduced into the vacuum chamber in which the main body 10 is placed. This hydrocarbon acts as a carbon source to grow a diamond film (i.e., the above-mentioned CVD diamond film 21) on the surface of the main body 10. When the thickness of this diamond film becomes sufficient (e.g., about 10 nm to 40 nm), step S3 is terminated. For example, the introduction of the hydrocarbon gas into the inside of the vacuum chamber is stopped, the generation of the above-mentioned hydrogen plasma is stopped, and the decompression in the vacuum chamber is stopped. In addition, in an example of the processing conditions of step S3, the energy of the microwave introduced into the chamber is about 250 W, the flow rate and pressure of the hydrogen gas introduced into the chamber are about 300 sccm and about 35 torr, respectively, the flow rate of the methane gas (CH ₄ ) into the chamber is about 0.2 sccm, the processing temperature (surface temperature of the main body 10) is about 600° C., and the processing time is about 2 hours. However, the processing conditions of step S3 are not limited to this.

The surface of the CVD diamond film 21 formed in step S3 was in contact with hydrogen plasma, so the diamond crystals that make up the surface are hydrogen-terminated. That is, on the surface of the CVD diamond film 21, a hydrogen atom is bonded to each dangling bond of the carbon atom, as shown in FIG. 6A or FIG. 6B.

In step S4, an oxygen termination process is performed to convert the hydrogen termination on the surface of the CVD diamond film 21 to a carbon termination. As a result, the diamond crystal that constitutes the surface of the CVD diamond film 21 has an oxygen atom bonded to each dangling bond of the carbon atom, as shown in FIG. 5A or FIG. 5B.

In step S4, for example, the diamond anvil 20 having the main body 10 and the CVD diamond film 21 formed on the surface of the main body 10 may be removed from the vacuum chamber and subjected to oxygen termination treatment. By performing oxygen termination treatment on the CVD diamond film 21, the diamond crystals constituting the surface of the CVD diamond film 21 are converted from a hydrogen-terminated state to an oxygen-terminated state.

The oxygen termination treatment may be, for example, a treatment in which the diamond anvil 20 is placed in a mixed solution of sulfuric acid and nitric acid, and the mixed solution is heated. In one example of the conditions for the oxygen termination treatment, the mixture ratio of nitric acid to sulfuric acid (nitric acid/sulfuric acid) is about 1/3, the temperature of the mixed solution is about 200° C., and the treatment time is about 30 minutes. However, the conditions for the oxygen termination treatment are not limited to these.
In addition, the oxygen termination treatment is not limited to the treatment using the above-mentioned mixed solution, and may be other treatments. For example, the oxygen termination treatment may be a treatment in which the CVD diamond film 21 formed on the body 10 is exposed to high-concentration ozone or oxygen plasma.

(Effects of this embodiment)
In this embodiment, a CVD diamond film 21 is formed on the surface of the diamond anvil 20 in a region including at least the tip surface 11. This makes it possible to prevent the diamond anvil 20 from being damaged by irradiating the sample and the diamond anvil 20 with X-rays for a long period of time while applying ultra-high pressure (e.g., 150 GPa to 200 GPa) to the sample using the diamond anvil 20.

The details are as follows. If the CVD diamond film 21 is not formed on the diamond body 10, the surface of the body 10 is mechanically polished, and therefore there is a possibility that extremely small cracks (for example, about 1 nm to 500 nm) on the order of nanometers may occur on the surface. Therefore, in this embodiment, the CVD diamond film 21 is formed on the surface of the body 10. Since extremely small cracks due to mechanical polishing do not occur in the diamond crystal on the surface of the CVD diamond film 21, it can be said that the diamond crystal on the surface is in good condition. As a result, as described above, when the diamond anvil 20 with the CVD diamond film 21 formed on the surface of the body 10 is irradiated with X-rays for a long time while applying ultra-high pressure to the sample, the diamond anvil 20 can be prevented from being damaged by the influence of X-rays.

As described above, the diamond crystals constituting the surface of the CVD diamond film 21 may be oxygen-terminated. In this case, as shown in FIG. 5B, cross-links can be formed by oxygen atoms bonded to the dangling bonds of the diamond crystals. This further stabilizes the diamond crystal structure on the surface of the CVD diamond film 21. As a result, damage to the diamond anvil 20 as described above can be further suppressed.

(Example)
In this embodiment, a pair of diamond anvils 20 were prepared, which were manufactured according to the above-mentioned flow chart of Fig. 7. As described above, each of the pair of diamond anvils 20 had a CVD diamond film 21 formed on its surface (tip face 11 and inclined face 12), and the diamond crystals constituting the surface of the CVD diamond film 21 were oxygen-terminated.

In addition, an experiment was conducted in which ultra-high pressure was applied to a sample using the pair of diamond anvils 20 described above, as shown in Figure 2. In this experiment, solidified hydrogen sulfide was used as the sample, and while applying ultra-high pressure of 145 GPa to the sample, X-rays with an energy of 18 keV were irradiated onto the diamond anvils 20 for more than 36 hours.

Actual images of the diamond anvil 20 before and after X-ray irradiation are shown in Figures 8A and 8B, respectively. Figures 8A and 8B are images of the tip surface 21a of the diamond anvil 20 observed from the back surface 15 side. Figures 8A and 8B show the state in which ultra-high pressure is applied to the sample by the diamond anvil 20. As shown in Figure 8B after X-ray irradiation, the diamond anvil 20 was not damaged by the above-mentioned experiment.

(Comparative Example)
On the other hand, in the comparative example, a pair of diamond anvils 10 were prepared by cutting and polishing natural diamond. These pair of diamond anvils 10 were the same as the diamond body 10 prepared in the above-mentioned step S1, and no CVD diamond film 21 was formed on their surfaces.

Using the pair of diamond anvils 10 prepared, an experiment was conducted in which ultra-high pressure was applied to a sample as shown in Figure 2. In this experiment, solidified hydrogen sulfide was used as the sample, and while applying ultra-high pressure of 135 GPa to the sample, X-rays with an energy of 18 keV were irradiated onto the diamond anvils 10 for about 24 hours.

9A and 9B show actual images of the diamond anvil 10 before and after the X-ray irradiation, respectively. 9A and 9B are images of the tip surface 11 of the diamond anvil 10 observed from the back surface 15 side. 9A and 9B show the state in which ultra-high pressure is applied to the sample by the diamond anvil 20. As shown in FIG. 9B after X-ray irradiation, the diamond anvil 10 was broken due to cracks caused by the above-mentioned experiment. This damage is thought to be caused by nanocracks on the surface of the diamond anvil 10. For example, it is thought that when hydrogen sulfide is compressed, hydrogen is generated and enters the cracks, and the hydrogen bonds unfavorably with the dangling bonds of the diamond crystal structure, resulting in a weakened crystal.

As can be seen from the above examples and comparative examples, by forming a CVD diamond film 21 on the surface of the main body 10, damage to the diamond anvil 20 can be suppressed. This is thought to be because the diamond on the surface of the CVD diamond film 21 does not have nanocracks and has good crystallinity. In addition, because the diamond crystals that make up the surface of the CVD diamond film 21 are oxygen-terminated, the crystals become even stronger, and it is expected that damage to the diamond anvil 20 will be further suppressed.

The present invention is not limited to the above-described embodiment, and various modifications can be made within the scope of the technical concept of the present invention. For example, the diamond anvil 20 according to the embodiment of the present invention does not have to have all of the above-described features, and may have only some of the above-described features.

In addition, any of the following modified examples 1 to 4 may be adopted, or any combination of two or more of modified examples 1 to 4 may be adopted. In this case, the points not described below are the same as those described above.

(Modification 1)
The diamond anvil 20 of the present invention may be one in which a CVD diamond film 21 is formed on the surface of a body 10 obtained by cutting an artificially produced synthetic diamond and polishing the surface.

(Modification 2)
The diamond anvil 20 of the present invention may be any type that pressurizes a sample by sandwiching the sample between its tip surface 21a and another diamond. The other diamond may be the same as the diamond anvil 20, or may be a diamond of a different shape (e.g., a diamond in the form of a substrate). A CVD diamond film may also be formed on the surface of the diamond of a different shape.

(Modification 3)
The process for forming the CVD diamond film 21 on the surface of the diamond anvil 10 is not limited to the above-mentioned example.

(Modification 4)
It is difficult to distinguish between the diamond anvil 20 on which the CVD diamond film 21 is formed and the diamond anvil 10 on which the CVD diamond film 21 is not formed based on their structures. Therefore, a mark for indicating that the CVD diamond film 21 is formed may be formed as a local recess of any predetermined shape on the surface (inclined surface 21b) of the CVD diamond film 21. The predetermined shape may be a regular shape or a characteristic shape (e.g., a T-shape) that indicates that it is artificially formed so that the mark can be distinguished from scratches, etc. Figure 10 shows the case where the mark 22 is provided in Figure 4B.

The above-mentioned predetermined shape of the mark 22 means the shape (approximately rectangular in FIG. 10) as seen from a direction perpendicular to the surface (e.g., inclined surface 21b) of the CVD diamond film 21 at the position of the mark 22. The dimensions of the mark 22 (dimensions in each direction along the surface of the CVD diamond film 21) may be on the order of submicrometers or micrometers (e.g., 0.1 μm to 10 μm), but are not limited thereto. The depth of the recess as the mark 22 is the same as the above-mentioned thickness of the CVD diamond film 21. Here, the depth may be the depth in a direction perpendicular to the surface of the CVD diamond film 21 at the position of the mark 22.

The mark 22 can be provided as follows. Before forming the CVD diamond film 21 on the surface of the diamond anvil 10 (for example, before the above-mentioned step S2), a metal mask (metal micro-part) for the micro mark 22 is provided at a local position (for example, one location) on the surface (for example, the inclined surface 12) of the diamond body 10. That is, a metal mask (metal micro-part) is provided at a local position on the surface (for example, the inclined surface 12) of the body 10, and in this state, the CVD diamond film 21 may be formed on the surface of the body 10 (for example, the above-mentioned steps S2 to S4 may be performed). Since the CVD diamond film 21 is not formed on the metal mask, the metal mask is dissolved in acid after the formation of the CVD diamond film 21, so that the mark 22 of any shape can be provided as a recess on the surface (for example, the inclined surface 21b) of the diamond anvil 20.

The metal mask may be formed on the inclined surface 12 that does not affect the generation of pressure, for example, by using lithography. The metal mask is, for example, a rectangle with an area of about 1 ^μm2 and a thickness of about 100 nm. Here, the rectangle refers to the shape when viewed from a direction perpendicular to the surface of the diamond anvil 20 (for example, the inclined surface 21b) at the position of the metal mask, and the thickness refers to the thickness in the perpendicular direction. However, the area, shape, and thickness of the metal mask are not limited to the above example.

In this modification example 4, by confirming the presence of the mark 22, it is possible to identify the diamond anvil 20 as one on which a CVD diamond film 21 has been formed.

10 Diamond anvil (main body)
11 Tip surface (curette)
12 inclined surface 13 base portion 14 gasket 15 bottom surface 20 diamond anvil 21 CVD diamond film 21a tip surface 21b inclined surface 22 mark (recess)
C central axis

Claims (9)

A method for manufacturing a diamond anvil for pressing a sample, comprising the steps of:
(A) Prepare a diamond body;
(B) forming a CVD diamond film on the surface of the body by chemical vapor deposition to produce a diamond anvil having the body and the CVD diamond film;
A method for manufacturing a diamond anvil, comprising the steps of: before (B), contacting the surface of the body with hydrogen plasma. A method for manufacturing a diamond anvil for pressing a sample, comprising the steps of:
(A) Prepare a diamond body;
(B) forming a CVD diamond film on the surface of the body by chemical vapor deposition to produce a diamond anvil having the body and the CVD diamond film;
The method for producing a diamond anvil further comprises, after (B), carrying out an oxygen termination treatment for oxygen-terminating diamond crystals constituting the surface of the CVD diamond film. The method for manufacturing a diamond anvil according to claim 2, wherein the surface of the body is contacted with hydrogen plasma before (B). The method for manufacturing a diamond anvil according to claim 1, further comprising the step of performing oxygen termination treatment to oxygen-terminate the diamond crystals that constitute the surface of the CVD diamond film after step (B). The body has a tip surface corresponding to a location where a sample is placed,
5. The method for manufacturing a diamond anvil according to claim 1, wherein in (B), the CVD diamond film is formed on a region of the surface of the body that includes at least the tip face. The method for manufacturing a diamond anvil according to any one of claims 1 to 5, wherein the main body is obtained by cutting a diamond into a predetermined shape and polishing the surface of the cut diamond of that shape. Before (B), a metal mask is provided at a localized position on the surface of the body;
(B) is performed while the metal mask is provided at the local position;
7. The method for manufacturing a diamond anvil according to claim 1 , further comprising the steps of: after (B), dissolving the metal mask in an acid to form marks as localized depressions of a predetermined shape on the surface of the CVD diamond film. A method for using a diamond anvil manufactured by the manufacturing method according to any one of claims 1 to 7, comprising the steps of:
A method for using a diamond anvil, comprising the steps of: irradiating a sample, which is pressed by the diamond anvil and has an unpolished surface of the CVD diamond film, with X-rays. A diamond anvil for pressing a sample,
A diamond body and a CVD diamond film formed on a surface of the body,
The diamond crystals constituting the surface of the CVD diamond film are oxygen-terminated with oxygen atoms bonded to each dangling bond of a carbon atom without any hydrogen termination being present.

Images