JP2010030854A - Carbon onion particle dispersed film and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a carbon onion particle dispersed film which is composed of a single layer containing a carbon onion particle, and to provide a manufacturing method of a carbon onion particle dispersed film which can manufacture the same at a low cost. <P>SOLUTION: The carbon onion particle dispersed film is composed of a mixed layer which contains carbon onion particles, metal particles and an amorphous phase. The manufacturing method of a carbon onion particle dispersed film is provided with an irradiating step for irradiating a pulse laser on the surface of a substrate containing a metal carbide at least on the surface, wherein the pulse laser has an irradiation strength of not less than 5×10<SP>13</SP>W/cm<SP>2</SP>and not more than 10<SP>17</SP>W/cm<SP>2</SP>. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a carbon onion particle dispersion film and a method for producing the same, and more particularly to a carbon onion particle dispersion film usable for a solid lubricant, an electronic device and the like, and a method for producing the same.

Carbon onion is a type of giant fullerenes, the outer periphery of the core consisting of fullerenes, such as C _60, several to several hundred layers about the graphite layer spherical are nano-sized particles were laminated as onion. Carbon onion is excellent in light weight, resistance to radiation, stability under high temperature and pressure, and can isolate foreign substances inside, so it is expected to be applied to solid lubricants and various electronic devices. .

The synthesis method of carbon onion is
(1) High energy electron beam irradiation to soot in vacuum,
(2) Vacuum heat treatment of diamond particles,
(3) High-frequency plasma CVD method using silica gel carrying a catalyst,
(4) C ion implantation into Ag, Cu, etc.
(5) Amorphous SiC laser irradiation,
(6) Simultaneous sputtering of C and catalytic metal, or unbalanced magnetron sputtering of C,
Etc. have been reported.
Among these, (1) to (3) are methods for synthesizing carbon onion powder, and (4) to (6) are methods for forming a thin film containing carbon onion.

Specific examples of reports relating to the method for producing carbon onion powder or carbon onion-containing thin film include the following.
For example, Patent Document 1 uses a silicon wafer and graphite as a base material and a sputtering target, respectively, and sputters graphite using an unbalanced magnetron sputtering method while applying a positive bias potential to the base material. A method for producing a carbon onion film that forms a film on the surface of a substrate is disclosed.
In the same document,
(1) In the process of forming a thin film, a thin film having a carbon onion cluster can be formed by irradiating an electron beam having appropriate energy and flux, and
(2) When an unbalanced magnetron sputtering method is used, a high plasma density is also formed in the vicinity of the substrate, so that an electron flux having a higher electron density can be irradiated to the thin film being formed, and the onion cluster The formation is promoted,
Is described.

In addition, in Patent Document 2,
(1) Using a magnetron sputtering method, a carbon-based amorphous thin film having a film thickness of about 0.2 μm is formed on a Si substrate,
(2) An Al thin film is formed in a predetermined pattern on the surface of the carbon-based amorphous thin film,
(3) Fe ions are implanted into the carbon-based amorphous thin film using the Al thin film as a mask,
(4) After removing the Al thin film, the carbon-based amorphous film is irradiated with an electron beam.
A method for producing a carbon-based thin film is disclosed.
In the same document, the formation of graphite clusters is suppressed even when irradiated with an electron beam in a region where Fe ions are not implanted, whereas when an electron beam is irradiated onto a region where Fe ions are implanted, graphite is not required at high temperatures. The point that the generation of clusters is promoted is described.

Patent Document 3 discloses nano-sized spherical graphite in which ultrafine carbon black is suspended in acetone, the supernatant liquid is scooped up with a carbon microscope grid, and a strong electron beam is irradiated to the carbon black in an electron microscope for a short time. A manufacturing method is disclosed.
In the same document, when a strong electron beam is irradiated to soot-like carbon having a cage-like aggregate structure of nano-primary particles formed by overlapping irregular concentric circles, the primary particles change to spherical carbon nano-onions. The point to do is described.

Non-Patent Document 1 includes
(1) An amorphous SiC thin film having a film thickness of 100 to 200 nm and a stoichiometric composition is formed on the surface of a 6H-SiC substrate by a pulse laser deposition method.
(2) One shot of KrF laser (pulse width: 25 nsec, laser fluence: 800 mJ / cm ² (equivalent to irradiation intensity = 3.2 × 10 ¹⁰ W / cm ² ), wavelength: 248 nm) at a substrate temperature of 600 ° C. Irradiate the surface of the amorphous SiC thin film,
A method for producing carbon onions is disclosed.
In the same document,
(A) When amorphous SiC heated to 600 ° C. is irradiated with a laser, a region near the surface having a depth of about 50 to 100 nm crystallizes in a cubic system,
(B) Since Si volatilizes during irradiation, a carbonaceous layer with a thickness of about 10 nm is formed on the surface.
(C) Onion-like carbon clusters are formed in both the upper carbonaceous layer and the inner polycrystalline cubic SiC region, and (d) the onion particles formed in the polycrystalline SiC are larger. , Less defects,
Is described.

Non-Patent Document 2 includes
(1) An Ag thin film having a thickness of 300 nm is formed on the surface of a fused silica substrate,
(2) At 500 ° C., carbon ions are injected into the Ag thin film,
(3) A method for producing a carbon onion thin film is disclosed in which a substrate is annealed in vacuum at 850 ° C. for 10 hours to thermally volatilize an Ag component.
This document describes that the obtained carbon onion particles are almost completely spherical, and the average size of the carbon onion varies depending on the amount of C injected.

Furthermore, although not a method for producing carbon onion particles, Non-Patent Document 3 discloses a SiC nano-processing method using a femtosecond laser.
In this document, laser irradiation is performed on 4H-SiC under the conditions of a wavelength of 400 nm, a pulse energy of 25 μJ / pulse (equivalent to irradiation intensity = 1.1 × 10 ¹⁰ W / cm ² ), a repetition frequency of 50 Hz, and a pulse number of 100. And the point that the ripple structure (periodic uneven structure) which has two types of periods on the surface is formed is described.

JP 2002-105623 A JP 2006-219363 A JP 2001-048508 A Chem. Phys. Lett., 373 (2003) 642 Chem. Phys. Lett., 320 (2000) 202 Takuro Tomita, “Micro / nano-processing of SiC using ultra-short pulse laser and its application”, Industrial Materials, vol.55, No.11, (2007) p56

In order to apply the carbon onion particles to various electronic devices and solid lubricants, it is necessary to firmly bond the carbon onion particles with an appropriate thickness to the surface of the base material.
However, all of the conventionally known methods for synthesizing carbon onion particles are complicated and expensive. Therefore, the method of forming a thin film on a substrate using such a powder has a problem of further increasing the cost of the thin film.
On the other hand, among the methods for producing a carbon onion particle-containing thin film, the method disclosed in Patent Document 2 is a multi-step process (deposition of carbon-based amorphous thin film → mask preparation → ion implantation → mask removal → electron beam irradiation). Is necessary and the cost performance is poor. Further, the method disclosed in Non-Patent Document 2 has a problem that a dense film cannot be obtained because Ag needs to be removed after carbon ions are implanted.

In contrast, as disclosed in Non-Patent Document 1, when amorphous SiC is irradiated with a laser, a film containing carbon onion particles can be formed on the surface.
However, this method requires heating the substrate to 600 ° C., which is not only expensive, but also limits the applicable substrate material. Further, the treated film has a two-layer structure of a carbonaceous thin film containing carbon onion and a crystalline SiC film containing carbon onion, and a single layer film containing carbon onion cannot be obtained.

The problem to be solved by the present invention is to provide a carbon onion particle dispersion film comprising a single layer containing carbon onion particles.
Another problem to be solved by the present invention is to provide a method for producing a carbon onion particle dispersion film capable of producing such a carbon onion particle dispersion film at low cost.

In order to solve the above problems, the carbon onion particle dispersion film according to the present invention comprises a mixed layer containing carbon onion particles, metal particles, and an amorphous phase.
In addition, the method for producing a carbon onion particle dispersion film according to the present invention,
Comprising an irradiation step of irradiating a surface of a substrate containing metal carbide at least on its surface with a pulsed laser;
The gist of the pulse laser is that the irradiation intensity is 5 × 10 ¹³ W / cm ² or more and 10 ¹⁷ W / cm ² or less.

When the surface of a substrate containing metal carbide is irradiated with a pulse laser having a high irradiation intensity, a carbon onion particle dispersion film composed of a mixed layer containing carbon onion particles, metal particles, and an amorphous phase is formed on the substrate surface. can get.
Although this generation mechanism is not clear, it is estimated as follows.
(1) When a powerful pulse laser is irradiated onto a metal carbide, all or part of the metal carbide near the surface is decomposed into C and metal, and the metal melts in a state where C is dissolved in supersaturation.
(2) The surface whose temperature has risen is instantaneously cooled, and the supersaturated C contained in the molten metal first forms fullerene.
(3) Graphite layers are successively stacked around the generated fullerene to deposit carbon onion particles.
(4) A part of the melt produced by the decomposition of the metal carbide precipitates in the form of crystalline metal particles during cooling, and the part that cannot be crystallized remains as an amorphous phase.

Hereinafter, an embodiment of the present invention will be described in detail.
[1. Carbon onion particle dispersion film]
The carbon onion particle dispersion film according to the present invention comprises a mixed layer containing carbon onion particles, metal particles, and an amorphous phase. The carbon onion particle dispersion film may further contain metal carbide particles.

[1.1 Carbon onion particles]
In the present invention, “carbon onion particles” refer to particles having a spherical shell structure in which a plurality of graphite C-planes are laminated in an onion-like shape or concentric spherical shape. The central part of the carbon onion particles may or may not have a spherical shell structure. Note that the C-plane of graphite constituting the carbon onion particles need not be defect-free.

As will be described later, the carbon onion particle-dispersed film can be produced by irradiating at least the surface of a substrate containing a metal carbide M ₂ C on the surface thereof with a pulse laser. The in-plane number density and average diameter of the carbon onion particles contained in the film can be controlled by the composition of the pulse laser irradiation surface, the pulse laser irradiation conditions, and the like.
For example, in the case of producing a carbon onion particle-dispersed film using the method described later, when the production conditions are optimized, a film having an in-plane number density of carbon onion particles of 1 / 0.01 μm ² or more can be obtained. Further, when the production conditions are optimized, a film containing carbon onion particles having an average diameter of 2 nm to 50 nm can be obtained.

[1.2 Metal particles]
The metal element M ₁ constituting the metal particles includes the metal element M ₂ constituting the metal carbide M ₂ C existing on the laser irradiation surface. When the metal carbide M ₂ C is a mixture or composite including two or more metal elements M ₂ , the metal element M ₁ includes at least one metal element M ₂ . In the present invention, the term “metal element” includes metalloid elements such as Si.

Since the metal particles are generated by decomposing the metal carbide M ₂ C with a pulse laser, the metal element M ₁ constituting the metal particles is formed of a metal carbide capable of forming. Specific examples of such metal element M ₁ include group IVA elements (Ti, Zr, Hf), group VA elements (V, Nb, Ta), group VIA elements (Cr, Mo, W), group IVB. There are elements (Si, Ge, Sn, Pb) and the like. The metal particles may contain any one of these metal elements M ₁ , or may be a mixture or alloy containing two or more metal elements M ₁ .
For example, when the metal carbide M ₂ C present on the laser irradiation surface is SiC, Si particles are generated in the film by irradiation with a pulsed laser under predetermined conditions.

The composition, number and average diameter of the metal particles contained in the film can be controlled by the composition of the pulse laser irradiation surface, pulse laser irradiation conditions, and the like.
For example, in the case of producing a carbon onion particle-dispersed film using the method described later, when the production conditions are optimized, a film containing metal particles having an average diameter of 0.1 nm to 1000 nm is obtained.
For example, when C-rich amorphous SiC is contained on the pulse laser irradiation surface, a film having a relatively small content of metal particles can be obtained.

[1.3 Amorphous phase]
The amorphous phase is considered to be produced by the precipitation of metal particles and carbon onion particles from the molten metal produced by the decomposition of the metal carbide M ₂ C and then solidification of the remaining melt. Therefore, the amorphous phase contains one or more selected from the metal elements M ₂ and C constituting the metal carbide M ₂ C existing on the pulse laser irradiation surface. In addition, gas (for example, oxygen) in the atmosphere may be mixed into the molten metal during pulse laser irradiation.
The amount of the amorphous phase contained in the film can be controlled by the composition of the pulse laser irradiation surface, the pulse laser irradiation conditions, and the like.

[1.4 Metal carbide particles]
The carbon onion particle dispersion film according to the present invention may contain a metal carbide M ₃ C.
As the metal carbide M ₃ C contained in the film, specifically,
(1) Metal carbide M ₂ C existing on the laser irradiation surface remains unreacted or re-deposited,
(2) those in which all or part of the metal carbide M ₂ C by laser irradiation reacts, freshly precipitated as different carbides in composition and / or crystal structure,
and so on.
Accordingly, the metal element M ₃ constituting the metal carbide M ₃ C particles includes all of the metal elements M ₂ constituting the metal carbide M ₂ C existing on the laser irradiation surface, and one of the metal elements M ₂ . May include parts.

The metal element M ₃ constituting the metal carbide M ₃ C is capable of forming a metal carbide. Specifically, as such a metal element M ₃ , a group IVA element (Ti, Zr, Hf), a group VA element (V, Nb, Ta), a group VIA element (Cr, Mo, W), a group IVB There are elements (Si, Ge, Sn, Pb) and the like. The metal carbide M ₃ C particles may contain any one of these metal elements M ₃ , or may be a mixture or composite containing two or more metal elements M ₃ . Further, the metal element M ₃ may be the same as or different from the metal element M ₁ constituting the metal particles in the film.
For example, when the metal carbide M ₂ C present on the laser irradiation surface is SiC, SiC particles may be contained in the film by irradiating a pulse laser under predetermined conditions.

The composition, number, and average diameter of the metal carbide M ₃ C particles contained in the film can be controlled by the composition of the pulse laser irradiation surface, pulse laser irradiation conditions, and the like.
For example, in the case of producing a carbon onion particle-dispersed film using a method described later, when the production conditions are optimized, a film containing metal carbide M ₃ C particles having an average diameter of 0.1 nm to 1000 nm is obtained.

[2. Manufacturing method of carbon onion particle dispersion film]
The method for producing a carbon onion particle dispersion film according to the present invention includes an irradiation step of irradiating the surface of a base material containing metal carbide on at least the surface thereof with a pulse laser.

[2.1 Substrate]
The substrate consists of those containing a metal carbide M ₂ C at least on its surface. The base material may contain the metal carbide M ₂ C as a whole, or may contain the metal carbide M ₂ C only on the surface. Further, at least the surface of the substrate may be composed of only the metal carbide M ₂ C, or a phase different from the phase composed of the metal carbide M ₂ C (for example, metal phase, oxide phase, nitride phase). Etc.).
The shape of the substrate is not particularly limited, and substrates having various shapes can be used according to the purpose.

The metal element M ₂ constituting the metal carbide M ₂ C is capable of forming a metal carbide. Specific examples of such metal element M ₂ include group IVA elements (Ti, Zr, Hf), group VA elements (V, Nb, Ta), group VIA elements (Cr, Mo, W), group IVB. There are elements (Si, Ge, Sn, Pb) and the like. The metal carbide M ₂ C may include any one of these metal elements M ₂ , or may be a mixture or composite including two or more metal elements M ₂ .

Specifically, as a base material,
(1) A single crystal, polycrystalline, or amorphous substrate made of metal carbide M ₂ C (for example, SiC, TiC, ZrC, WC, VC, NbC, etc., or a mixture or composite containing two or more thereof) ,
(2) metal carbide M ₂ C phase and other phases (e.g., a metal phase, an oxide phase, such as nitride phase) substrate made of a complex with (for example, a substrate made of WC-Co alloy),
(3) A substrate (for example, the surface of a polycrystalline SiC wafer) on which a crystalline or amorphous thin film containing a metal carbide M ₂ C is formed on the surface of a support made of a metal material, an organic material, a non-metallic inorganic material, or the like A substrate on which an amorphous SiC thin film is formed),
and so on.

[2.2 Pulsed laser irradiation]
The substrate surface is irradiated with a pulse laser. In order to obtain a carbon onion particle dispersion film, it is necessary to irradiate a powerful pulse laser. If the irradiation intensity of the pulse laser is too low, only a periodic uneven structure is formed on the surface of the substrate, and carbon onion particles cannot be formed (for example, see Non-Patent Document 3). Therefore, the irradiation intensity of the pulse laser needs to be 5 × 10 ¹³ W / cm ² or more.
On the other hand, if the irradiation intensity of the pulse laser is too high, the generated carbon onion particle dispersion film is blown off, or the generated carbon onion particles become amorphous. Therefore, the irradiation intensity of the pulse laser needs to be 10 ¹⁷ W / cm ² or less.
The optimum irradiation intensity is preferably selected according to the composition of the substrate surface, the characteristics required for the carbon onion particle dispersion film, and the like.

The pulse width of the pulse laser affects the state of the film. In general, if the pulse width is too narrow, the energy input to the substrate surface is reduced, and the amount of carbon onion particles produced is reduced. Therefore, the pulse width is preferably 1 fsec or more.
On the other hand, if the pulse width is too wide, energy input to the substrate surface becomes excessive, and carbon onion particles are not generated. Therefore, the pulse width is preferably 100 psec or less.
The optimum pulse width is preferably selected according to the composition of the substrate surface, the characteristics required for the carbon onion particle dispersion film, and the like.

Furthermore, carbon onion particles are formed by irradiating a powerful laser with a very short pulse width. Therefore, when a single region is irradiated with a powerful pulse laser many times, carbon onion particles generated by the last pulse laser irradiation may be destroyed by repeated pulse laser irradiation and become amorphous. Therefore, it is preferable to irradiate one pulse laser beam having a predetermined irradiation intensity on one region.
In order to form a carbon onion particle-dispersed film in a predetermined range on the surface of the substrate, the pulse laser or the substrate may be irradiated while moving in two dimensions. At this time, it is necessary to reduce the overlap of the irradiation portions of one pulse as much as possible.
As another method of forming a carbon onion particle dispersion film in a predetermined range on the surface of the substrate, a mask with a predetermined pattern is formed by enlarging the laser irradiation diameter and equalizing the in-plane irradiation intensity. There is a method of irradiating a laser beam on the surface of the substrate.

The irradiation diameter of the pulse laser affects the state of the film. Generally, if the irradiation diameter is too small, it takes a long time to irradiate a predetermined area with a pulse laser, which is not preferable.
On the other hand, if the irradiation diameter is too large, the irradiation intensity within the irradiation surface becomes non-uniform, or a pulse laser with a predetermined irradiation intensity cannot be irradiated, which is not preferable.
The optimum irradiation diameter is preferably selected according to the composition of the substrate surface, the characteristics required for the carbon onion particle dispersion film, and the like.

  When irradiating with a pulse laser, the substrate may be heated to an appropriate temperature. However, heating of the base material is not necessarily required, and carbon onion particles can be generated even by treatment at room temperature if the irradiation intensity is appropriate.

[2.3 Other steps]
The substrate on which the carbon onion particle dispersion film is formed on the surface can be used for various applications as it is. Alternatively, the substrate can be removed and the carbon onion particle dispersion film can be used alone. The method for removing the substrate is not particularly limited, and a known method (for example, an etching method) can be used depending on the type of the substrate.
Further, heat treatment may be performed to increase the size of the metal particles or carbide particles in the carbon onion particle-dispersed film, or to remove strain in the film.

[3. Action of carbon onion particle dispersion film and method for producing the same]
When the surface of a substrate containing metal carbide is irradiated with a pulse laser having a high irradiation intensity, a carbon onion particle dispersion film composed of a mixed layer containing carbon onion particles, metal particles, and an amorphous phase is formed on the substrate surface. can get. In addition, it is not necessary to heat the substrate to a high temperature. Further, a film composed of a single layer containing carbon onion particles is obtained, and a plurality of layers containing carbon onion particles are not formed. Furthermore, the obtained film is dense and does not necessarily require a post-process after film formation.

  This is considered due to the following reasons. That is, when the metal carbide is irradiated with a powerful pulse laser, all or part of the metal carbide near the surface is decomposed into C and metal. At this time, since the temperature in the vicinity of the surface reaches about 4000 K, the metal melts in a state where C is dissolved in supersaturation. On the other hand, since the pulse width of the laser is extremely short, the surface whose temperature has risen is instantaneously cooled, and the supersaturated C contained in the molten metal first forms fullerene. Furthermore, graphite onion is deposited one after another around the generated fullerene, and carbon onion particles are deposited. A part of the melt produced by the decomposition of the metal carbide precipitates in the form of crystalline metal particles during cooling, and the part that could not be crystallized remains as an amorphous phase.

  Since carbon onion particles are giant fullerenes, they are expected to be applied as various functional materials such as solid lubricants and electronic devices. In the carbon onion particle dispersion film according to the present invention, since metal particles and metal carbide particles coexist in the dense film in addition to the carbon onion particles, it is possible to expect dramatic improvement in characteristics and expression of new characteristics. Furthermore, the manufacturing method according to the present invention can form a film containing carbon onion particles at a room temperature by an extremely short time treatment, so that the cost of the process can be reduced.

Example 1
[1. Preparation of sample]
As a target, a commercially available ultrahigh purity polycrystalline SiC wafer (30 × 30 × 0.5 mm) prepared by a CVD (Chemical Vapor Deposition) method was prepared. The crystal system of the polycrystalline SiC is cubic 3C—SiC, and is an oriented polycrystalline body whose wafer surface corresponds to the (111) plane. The target was placed on a target holding jig having a translation mechanism in a vacuum chamber.
The laser was focused by the off-axis parabolic mirror in the vacuum chamber and irradiated onto the target surface. The irradiation diameter was major axis: about 50 μm × short axis: about 25 μm, and the irradiation intensity was 10 ¹⁶ W / cm ² . During irradiation, the target was not heated and moved in the horizontal direction at a speed of 2.5 mm / sec at room temperature to form irradiation traces for each pulse. The degree of vacuum during irradiation was 10 ⁻⁵ Torr (1.33 × 10 ⁻³ Pa). The laser used was a Ti-sapphire laser with a wavelength of 800 nm, and the pulse width was 70 fsec.

[2. result]
In FIG. 1, the Raman scattering spectrum of an irradiated part and an unirradiated part (3C-SiC) is shown.
The irradiation part
(1) peak of 520 cm ^-1 derived from crystal Si,
(2) 1360 cm ⁻¹ and 1590 cm ⁻¹ peaks derived from graphite-like carbon, and
(3) It consisted of a weak peak derived from 3C-SiC.
This result is presumed that SiC is decomposed into Si and C by laser irradiation, and the decomposed Si is precipitated as crystals, and partly undecomposed SiC remains or reprecipitates as it is.

In FIG. 2, the cross-sectional TEM image of an irradiation part and the electron beam diffraction pattern of a 1st layer are shown. The irradiation part consisted of two layers different from the original 3C—SiC. The first layer had a thickness of about 100 nm, and the presence of single crystal Si, single crystal 3C-SiC, and graphite structure was confirmed from the electron diffraction pattern. The presence of single crystal Si, single crystal 3C-SiC, and graphite structure coincided with the results of the Raman scattering spectrum shown in FIG.
In contrast, the second layer had a thickness of about 100 nm, and the presence of only 3C—SiC was confirmed from the electron diffraction pattern. From the TEM image, it looks different from the original 3C-SiC, but many linear patterns are dislocations, and it is inferred that many dislocations were generated by laser irradiation.

FIG. 3 shows a high-magnification TEM image in different regions (three fields of view) of the first layer. A carbon onion (C-onion) with a graphite surface wound in an onion shape and crystalline Si particles were observed. However, the presence of 3C-SiC could not be confirmed from the TEM image. This is presumably because the number density is low or very small because the signal intensity in the Raman scattering spectrum and electron diffraction pattern is weak.
From the high-magnification TEM image, crystalline Si and carbon onion could be confirmed, but other regions were also present. This region is considered an amorphous phase. Si, C, and O can be considered as constituent elements of the amorphous phase. It is considered that O may be mixed because the vacuum degree of the vacuum chamber at the time of laser irradiation is not so good.
The dimensions of carbon onion and Si particles were measured from a plurality of high magnification TEM images. They were 26 ± 2.4 nm and 9.3 ± 3.0 nm, respectively. The in-plane number densities were 9.5 / 0.01 μm ² and 76 / 0.01 μm ² , respectively.

  The current (I) -voltage (V) characteristics of the irradiated part were measured by a two-terminal two-probe method. The distance between the probes was about 20 μm. FIG. 4 shows the result. The IV relationship in the low voltage range is a straight line, but it shows a unique characteristic that increases stepwise at ± 10 V and ± 15 V and further increases the slope. This is thought to be due to the fact that the current bearer is Si particles of about 10 nm and a larger carbon onion, and the path through which electrons flow depends on the voltage.

(Example 2)
[1. Preparation of sample]
The laser was irradiated onto the 3C-SiC wafer by one pulse under the same conditions as in Example 1 except that the laser pulse width was 150 fsec and the irradiation intensity was 9 × 10 ¹⁴ W / cm ² .

[2. result]
The Raman scattering spectrum of the irradiated part was the same as in Example 1. Moreover, formation of the 1st layer and the 2nd layer was confirmed by cross-sectional TEM observation similarly to Example 1. FIG.
FIG. 5 shows a TEM image of the first layer. In the figure, the position and size of the carbon onion are schematically shown by circles having different diameters. The diameter and in-plane number density of the carbon onion particles were 26 ± 4.0 nm and 18 particles / 0.01 μm ² , respectively. Also in this case, similarly to Example 1, the irradiated part was formed with carbon onions, Si particles, 3C-SiC particles, and an amorphous phase.

(Example 3)
[1. Preparation of sample]
Except for setting the laser irradiation intensity to 10 ¹⁴ W / cm ² , the laser was irradiated to the 3C-SiC wafer by one pulse under the same conditions as in Example 1.

[2. result]
The Raman scattering spectrum of the irradiated part was the same as in Example 1. FIG. 6 shows an SEM image of the surface of the irradiated part. On the surface of the irradiated part, a large number of 20 to 60 nm trace particles considered to be carbon onions were precipitated. Also in this case, similarly to Example 1, it is presumed that the irradiated part was formed with carbon onions, Si particles, 3C-SiC particles, and an amorphous phase.

(Comparative Example 1)
[1. Preparation of sample]
Except for the laser irradiation intensity of 10 ¹³ W / cm ² , the 3C-SiC wafer was irradiated with only one pulse under the same conditions as in Example 1.
[2. result]
The irradiation part was the same as before irradiation, and the reaction as in the example did not occur.

(Comparative Example 2)
[1. Preparation of sample]
The laser was an Nd-YAG laser with a wavelength of 532 nm, the pulse width was 7 nsec, the irradiation diameter was 3 mm, and the irradiation intensity was 2 × 10 ⁹ W / cm ^2. The SiC wafer was irradiated with one pulse of laser.
[2. result]
Although traces of the reaction occurred in the irradiated part, the generation of carbon onion could not be confirmed by cross-sectional TEM observation.

  Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above embodiments, and various modifications can be made without departing from the scope of the present invention.

  The carbon onion particle dispersion film and the manufacturing method thereof according to the present invention can be used as a solid lubricant, various electronic devices, and a manufacturing method thereof.

It is a Raman scattering spectrum of the laser irradiation part (upper figure) and the non-irradiation part (lower figure) of a high purity polycrystalline SiC wafer. It is a cross-sectional TEM image (left figure) of the carbon onion particle-dispersed film obtained in Example 1, and an electron beam diffraction pattern (right figure) of the first layer. 4 is a high-magnification TEM image in different regions (three fields of view) of the carbon onion particle dispersion film obtained in Example 1. FIG. FIG. 2 is a current (I) -voltage (V) characteristic of the carbon onion particle dispersion film obtained in Example 1. FIG. 3 is a TEM image of a carbon onion particle dispersion film obtained in Example 2. FIG. 4 is a SEM image of a carbon onion particle dispersion film obtained in Example 3.

Claims (9)

  A carbon onion particle dispersion film comprising a mixed layer containing carbon onion particles, metal particles, and an amorphous phase. The carbon onion particle-dispersed film according to claim 1, wherein the in-plane number density of the carbon onion particles is 1 / 0.01 μm ² or more.   The carbon onion particle dispersion film according to claim 1 or 2, wherein an average diameter of the carbon onion particles is 2 nm or more and 50 nm or less.   The carbon onion particle dispersion film according to any one of claims 1 to 3, wherein an average diameter of the metal particles is 0.1 nm or more and 1000 nm or less.   The carbon according to any one of claims 1 to 4, wherein the metal particles include one or more elements selected from an IVA group element, a VA group element, a VIA group element, and an IVB group element (excluding C). Onion particle dispersion film.   The carbon onion particle dispersion film according to any one of claims 1 to 5, further comprising metal carbide particles. Comprising an irradiation step of irradiating a surface of a substrate containing metal carbide at least on its surface with a pulsed laser;
The pulse laser is a method for producing a carbon onion particle-dispersed film having an irradiation intensity of 5 × 10 ¹³ W / cm ² or more and 10 ¹⁷ W / cm ² or less.   The method for producing a carbon onion particle-dispersed film according to claim 7, wherein the pulse laser has a pulse width of 1 fsec to 100 psec.   The method for producing a carbon onion particle-dispersed film according to claim 7 or 8, wherein the irradiation step irradiates one pulse with the pulse laser.

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