JP2006219363A - Carbon thin film and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a highly useful carbon thin film with two regions different in characteristics being exposed on the surface of the film. <P>SOLUTION: This carbon thin film has a first region 11 which contains a graphite cluster with a particle diameter of over 2 nm and a second region 12 which does not contain a graphite cluster with a particle diameter of over 2 nm, and the regions 11 and 12 are exposed on its surface and the first region 11 satisfies the condition (a), that is, it contains a metal element which is preferably Fe, Co, Ni, Al, Cu, or Au, and/or the condition (b), that is, it contains a plate-shaped graphite structure and/or an onion-shaped graphite structure. This thin film can be obtained, for example, by the selective injection of the above-mentioned element ion to a carbon-based amorphous thin film, and the irradiation of the thin film with an electron beam. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a carbon-based thin film and a method for producing the same.

  There are various types of carbon-based materials whose properties are greatly different depending on the variety of bonding modes of carbon. These forms include new materials that have been confirmed to have excellent characteristics, such as carbon nanotubes (CNT) and fullerenes, and that are expected to become widely used in the fields of electronic devices and hydrogen storage materials. Not only CNT and fullerene, but generally large energy is required to form an ordered carbon structure. On the other hand, amorphous carbon can be formed without requiring large energy, and can realize a wide variety of characteristics (mechanical, electrical, and optical characteristics).

  Even though they are composed of the same carbon, amorphous carbon has characteristics that are significantly different from crystalline carbon materials. One example is that graphite is electrically conductive or semi-insulating, whereas amorphous carbon is substantially insulating. Therefore, if a technique for manufacturing a material in which carbons having different characteristics are combined in a form that can be easily applied to a device is established, a new composite material may be provided.

  A carbon thin film containing a crystalline carbon structure and an amorphous carbon structure as it is formed is also known (for example, Non-Patent Document 1). However, this technology has a limit in the degree of freedom in designing carbon materials.

  The present inventor has proposed a carbon material using two carbon films having different characteristics (Patent Document 1). This carbon material is a multilayer film in which low-hardness hard carbon films containing graphite clusters having an average diameter of 2 nm or more and high-hardness hard carbon films containing graphite clusters having an average diameter of 1 nm or less are alternately laminated. This multilayer film becomes a coating film for various members with improved wear resistance and sliding properties.

A carbon thin film in which the amorphous carbon film is irradiated with a laser beam or an electron beam to partially graphitize the surface of the hard amorphous carbon film has also been proposed (Patent Document 2). In this carbon thin film, the graphitized region becomes a lubrication portion, and the remaining portion becomes a hard portion. The lubrication part is formed by scanning the surface of the amorphous carbon film with a laser beam or an electron beam.
M. Chhowalla et al. “Generation and deposition of fllerene- and nanotube-rich carbon thin films” Philosophical Magazine Letters, 1997, vol.75, No.5, pp329-335 JP 2001-261318 A JP 2003-268531 A

  Unlike the technique disclosed in Patent Document 1, according to the technique disclosed in Patent Document 2, regions having different characteristics can be introduced into a predetermined portion of the surface of the carbon thin film. As disclosed in Patent Document 2, when energy is supplied to the surface of the amorphous carbon film, very fine graphite fragments are generated. However, the particle size of this fragment is at most 2 nm. Usually, when an attempt is made to form a graphite structure having a larger particle size in an amorphous carbon film, it is necessary to supply a larger amount of energy, so that the film is lost. In addition, since it is necessary to scan with a laser beam or the like, there is room for improvement in manufacturing efficiency, particularly when a thin film having a large area or a thin film in which regions are to be arranged in a minute and complicated manner is obtained.

The present invention provides a new carbon-based thin film having the following characteristics. This carbon-based thin film has a first region including a graphite cluster having a particle size exceeding 2 nm and a second region not including a graphite cluster having a particle size exceeding 2 nm, and the first region and the second region are on the surface. It is exposed and at least one condition selected from the following a) and b) is satisfied.
a) The first region contains a metal element.
b) The first region includes at least one selected from a plate-like graphite structure and an onion-like graphite structure as a graphite cluster.

  Further, the present invention does not include the first region containing the metal element and the metallizing element by implanting metal element ions into a part of the thin film from the surface of the carbon-based amorphous thin film. Forming the second region and supplying energy to at least the first region, thereby suppressing the growth of the graphite clusters in the second region to such an extent that the particle size of the cluster is 2 nm or less. And a process for forming a graphite cluster having a particle size exceeding 2 nm, for example, a graphite cluster that is at least one selected from a plate-like graphite structure and an onion-like graphite structure, and a method for producing a carbon-based thin film.

  In the manufacturing method of the present invention, ions of metal elements are selectively implanted in the carbon-based amorphous thin film in advance, and the action of metal atoms derived from the implanted ions is used. It is possible to selectively form exceeding graphite clusters. When the graphite clusters having a large particle size are selectively introduced to set the regions, the difference in characteristics between the regions becomes remarkable. In addition, since the region is set by selectively implanting the ions, it is not necessary to define the region by selectively supplying energy. Therefore, according to the manufacturing method of the present invention, a carbon-based thin film in which regions having different characteristics are arranged in the film surface, particularly a thin film having a large area or a carbon-based thin film having a fine and complicated pattern, is efficiently and rationally used. Can be manufactured.

  In addition, ion implantation allows modification of the thin film beyond the vicinity of the surface. The shape and size of the graphite structure can be easily controlled by controlling the ion implantation amount and the like together with the energy supply mode. According to the present invention, it is possible to provide a highly useful carbon-based thin film having a certain thickness, with two regions having different characteristics exposed on the surface of the film.

  In the carbon-based thin film of the present invention, the first region includes a graphite cluster having a particle size of more than 2 nm, preferably 5 nm or more, more preferably 10 nm or more, and the second region is a graphite having a particle size of more than 2 nm. Does not include clusters. That is, the second region does not include graphite clusters or only includes very fine graphite clusters (graphite fragments). The particle size of this fragment is 2 nm or less. When the particle size is limited to this level, the graphite cluster cannot take a characteristic structure such as a plate shape or an onion shape.

The particle size of the graphite cluster, as is widely in the art, in the Raman spectrometry, is determined by the intensity ratio of the so-called D peak (~1350cm ^-1) and G peak (1500~1600cm ^-1) (Reference: Robertson J, “Diamond-like Amorphous Carbon”, Materials Science and Engineering, R37 (2002), 129-281; 165-168 in particular).

  In this specification, the “carbon-based” thin film specifically refers to a thin film containing 50 atomic% or more of carbon. Thus, in this specification, the main component contained by 50 atomic% or more is described by "system". The carbon-based thin film may contain components other than carbon as subcomponents. For example, in addition to the metal elements listed in condition a), the carbon-based thin film may further contain at least one selected from H, N, B, and Si. . “Amorphous” means a structure that does not have a periodic long-range order like a crystal. For example, amorphous carbon is called amorphous carbon, diamond-like carbon, glassy carbon, or the like. (These terms are not used distinctly).

  The metal element is preferably at least one selected from the group consisting of Fe, Co, Ni, Al, Cu and Au, and more preferably at least one element selected from the group consisting of Fe, Co and Ni.

  According to the present invention, it is possible to obtain a carbon-based thin film having a characteristic structure in which the c-axis of the plate-like graphite structure is oriented in the in-plane direction of the thin film. Here, the c-axis (<001> axis) being oriented in the in-plane direction of the thin film does not mean that all the c-axes of the graphite structure included in the film are oriented in the in-plane direction. This means that the c-axis is oriented not in the film thickness direction but in the in-plane direction of the thin film as a whole.

  In the carbon-based thin film of the present invention, the first region can have a depth of 10 nm or more, further 50 nm or more, and in some cases 100 nm or more from the surface of the thin film. The first region can be controlled by ion implantation energy or the like. Depending on the thickness of the thin film, the first region extends from the surface of the thin film to the bottom surface. In this case, the size of the first region and the second region in the film thickness direction (region thickness) is the same as the film thickness.

  The carbon-based thin film of the present invention only needs to satisfy the conditions a) and / or the condition b), and may satisfy both of the two conditions. As will be described later, if energy supply is continued after implanting metal element ions (metal ions), metal atoms derived from the implanted ions may diffuse to the surface of the thin film. If the surface layer with a high concentration of metal atoms is removed, a thin film that does not satisfy the condition a) can be obtained. It has been confirmed by experiments that when the supply of energy is continued to such an extent that metal atoms become highly concentrated on the surface of the thin film and there are portions in which no metal atoms are present, the thin film usually has plate-like graphite. A structure is formed.

Metal ions implanted into the thin film reduce the energy required for the formation of graphite clusters from amorphous carbon. In order to implant the ions into a part of the thin film, the ions may be implanted from the surface with the surface of the thin film partially masked. According to this method, it is not necessary to draw ions while giving a spatial distribution by making ions to be implanted into a beam shape. For masking the surface of the thin film, a plate-like member (template) such as a metal plate or a resin plate previously processed into a predetermined pattern may be used, and a metal thin film formed to have a predetermined pattern is used. Also good. In order to sufficiently promote the formation of graphite clusters, it is recommended that the ion implantation amount be 1 × 10 ¹⁵ / cm ² or more, for example, 5 × 10 ^{15 to} 5 × 10 ¹⁷ / cm ² . The ion implantation energy is not particularly limited, but may be appropriately selected from the thickness of the thin film and the depth at which ions are to be implanted (depth that requires graphitization), for example, 40 to 400 keV.

  The concentration of ions in the thin film before the energy supply is not limited as long as the formation of graphite clusters is promoted. However, in the region where ions are implanted (ion implantation region serving as the first region), the concentration of ions is 0.5. -30 atomic%, especially 5-20 atomic% are preferred.

  Although the energy supply method is not particularly limited, electron beam irradiation is an energy supply method suitable for generating graphite clusters. According to the electron beam irradiation, it is not necessary to heat the entire sample on which the apparatus and the thin film are formed as in normal heat treatment. The electron beam irradiation is particularly suitable when the carbon-based thin film is used in combination with a dissimilar material having low heat resistance.

The energy of the electron beam is preferably 100 keV or less, more preferably 60 keV or less, for example, 40 to 60 keV. The electron beam irradiation intensity is preferably 10 ¹⁹ / cm ² · sec or less, more preferably 10 ¹⁷ / cm ² · sec or less, and particularly preferably 10 ¹⁵ / cm ² · sec or less. The lower limit of the electron beam irradiation intensity is not particularly limited, but is preferably 10 ¹³ / cm ² · sec or more.

  Since high-energy electron beam irradiation is rather undesirable, it is not necessary to irradiate the electron beam in a high vacuum state. For example, irradiation may be performed under normal pressure. The ability to process a thin film without high pressure reduction is a great advantage when considering mass production.

  The electron beam irradiation may be performed in an oxygen-containing atmosphere such as air, but in this case, ozone is generated. If this is to be avoided, it may be performed in a non-oxidizing atmosphere containing no oxygen, for example, in an atmosphere made of an inert gas such as argon or nitrogen gas.

  The energy may be supplied by heating the thin film. In this case, it is preferable to heat the thin film at a temperature of 600 to 1000K, preferably 750 to 850K. This is because if the temperature is too low, sufficient graphite clusters are not formed, and if the temperature is too high, film loss due to carbon oxidation or hydrocarbonation becomes significant.

  The energy for generating the graphite cluster may be supplied to at least the first region, and the energy may be supplied only to the first region or may be supplied to the first region and the second region. Since ions are implanted in advance, the manufacturing method of the present invention does not require the use of a high energy beam such as a laser beam whose irradiation region is limited. It is also advantageous for mass production to supply an energy beam such as an electron beam over a large area without giving a spatial distribution.

  In the manufacturing method of the present invention, when the supply of energy to the first region is continued, an onion-like and / or plate-like graphite structure may be generated in this region. These graphite structures are observed by electron beam irradiation or heat treatment of soot. For example, a plate-like graphite structure is observed by heat treatment exceeding 1000 K of soot. However, onion and plate-like graphite structures are usually not selectively formed in a part of the thin film by supplying energy to the amorphous thin film.

  In particular, it has been conventionally considered that a film having an isotropic structure such as an amorphous carbon film does not form a plate-like structure even if it is simply irradiated with an electron beam. However, when an electron beam is irradiated onto the region into which metal ions are implanted, a plate-like structure is formed without requiring a high temperature. It is considered that the formation of the plate-like structure involves dynamic reconstruction of the amorphous structure due to the diffusion of metal ions to the surface of the thin film.

  In the manufacturing method of the present invention, after supplying energy until the metal atoms derived from the implanted metal ions diffuse and are biased near the surface of the thin film, the step of removing the metal atoms segregated near the surface is further performed. You may implement. This additional step is particularly useful when it is desired to avoid light absorption due to the presence of Fe or the like, for example, when a carbon-based thin film is used as a part of an optical device.

  The step of removing the metal atoms may be performed as a step of removing the surface layer of the thin film by dry etching or wet etching. The metal atom can be substantially removed from the thin film by the step of removing the metal atom.

  According to the present invention, it is possible to obtain a carbon-based thin film in which regions having different characteristics are arbitrarily arranged in the film surface. The first region and the second region can have different characteristics due to the formation of graphite clusters in the first region. For example, the first region can be given higher conductivity than the second region. Further, for example, the first region can be given a light transmittance lower than that of the second region in the visible to infrared to far infrared wavelength region.

  Although the thickness of a carbon-type thin film is not specifically limited, For example, it is good to set it as the range of 10 nm-5 micrometers, especially 50 nm-1 micrometer.

  The method for forming the carbon-based amorphous thin film is not particularly limited. This thin film may be formed by various conventionally known film forming methods, physical vapor deposition methods (PVD methods) represented by sputtering methods, various chemical vapor deposition methods (CVD methods), and the like. An example of a target used for the sputtering method is calcined graphite. When atoms such as Si and B are added to the film, a target containing the atoms may be used. The atmosphere may be an inert gas such as argon, but H and / or N is mixed into the film as an atmosphere containing at least one selected from a hydrogen atom-containing gas and a nitrogen atom-containing gas, for example, together with the inert gas. May be.

The material of the substrate used for forming the thin film is not particularly limited. For example, a semiconductor substrate such as silicon, an oxide substrate such as Al ₂ O ₃ or MgO, a metal substrate such as iron, aluminum, or an alloy containing these is appropriately used. Use it.

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

  First, as shown in FIG. 1, a carbon-based amorphous thin film 15 is formed on a substrate 30. Further, a thin film serving as a mask 31 is formed on the thin film 15 so as to have a predetermined pattern. Subsequently, metal ions 32 are implanted into the surface of the thin film 15. As a result, the ions 32 are implanted into the portion to be the first region in the thin film without narrowing the ion implantation region by beam drawing.

  Next, as shown in FIG. 2, the mask 31 is removed, and the thin film 15 is irradiated with an electron beam 33. The electron beam 33 does not need to narrow down the irradiation area, and may irradiate the entire surface of the thin film 15 at once. The irradiation of the electron beam 33 promotes the generation of graphite clusters in the region where ions are implanted (first region 11). In the region where the ions are not implanted (second region 12), the generation of the graphite cluster is sufficiently suppressed even when the electron beam is irradiated. Although FIG. 2 shows a mode in which the electron beam 33 is irradiated after the mask 31 is removed, the electron beam 33 may be irradiated through the mask 31 while leaving it.

  In this way, as shown in FIG. 3, the carbon-based thin film 10 to which the pattern of the mask 31 is transferred can be obtained. In this thin film 10, a strip-shaped first region 11 corresponding to the opening of the mask 31 where the graphite clusters have grown, and a strip-shaped second region 12 corresponding to the shielding portion formed by the mask 31 in which the growth of the graphite clusters is suppressed. And are arranged alternately. In the illustrated form, these regions 11 and 12 extend from the surface of the thin film to the bottom surface, and have the same thickness as the thickness of the thin film.

  As is clear from the above description, if the pattern of the mask 31 is changed, the regions 11 and 12 can be arranged at an arbitrary size and an arbitrary position. For example, as shown in FIG. 4, it is also possible to obtain a carbon-based thin film 10 in which one region (first region 11 in the figure) is a columnar region surrounded by the other region (second region 12). The shape of the columnar region 11 is not limited to a cylinder or a quadrangular column as illustrated.

  As shown in FIGS. 3 and 4, according to the present invention, a carbon-based thin film in which at least one, preferably both, selected from the following c) to d) can be obtained.

c) One of the regions selected from the first region 11 and the second region 12 is a columnar region surrounded by the other region, and the area of the columnar region on the surface of the carbon-based thin film is 200 nm ² or more, preferably 1000 nm ² or more, more preferably 10,000 nm ² or more.

  d) In the first in-plane direction 51, the first region 11 and the second region 12 are not less than twice the average diameter in the second in-plane direction 52 orthogonal to the first in-plane direction 51, preferably not less than 10 times. , And are alternately arranged in the second in-plane direction 52.

  Along with c) or instead of c), any one region selected from the first region 11 and the second region 12 is a columnar region surrounded by the other region, and the in-plane direction of this columnar region It is also possible to obtain a carbon-based thin film that satisfies the condition that the average diameter is about 100 nm, preferably 200 nm or more.

  However, the above c) and d) cannot be realized even if a carbon-based thin film (for example, a carbon-based thin film having a column-column structure) as it is formed has the above-mentioned a) or b). The arrangement of the regions is illustrated, and the shape and size of the regions introduced by the present invention are not limited to the above. As described above, the manufacturing method of the present invention is also suitable for manufacturing a carbon-based thin film having a fine and complicated region.

  In the carbon-based thin film 10 shown in FIG. 3, the first region 11 and the second region 12 are both arranged in a band shape. These band-like regions 11 and 12 have an average diameter of the first in-plane direction 51 that is equal to or larger than the degree described in d) above the average diameter in the second in-plane direction 52 perpendicular to the direction 51. In addition, the second in-plane directions 52 are alternately arranged. In the carbon-based thin film 10 shown in FIG. 4, the average diameter of the columnar first region 11 surrounded by the second region 12 is set so as to satisfy the above condition c). The shape of the columnar region 11 is not limited to a cylinder or a quadrangular column as illustrated.

  Hereinafter, although an example explains the present invention still in detail, like the above-mentioned explanation in this column, the following is only illustration of an embodiment of the present invention and does not limit the present invention.

  Using a magnetron sputtering method, a carbon-based amorphous thin film A having a thickness of about 0.2 μm was formed on a silicon substrate. Firing graphite was used as a target. The substrate temperature was room temperature (the substrate was water-cooled), and the atmospheric pressure was 0.27 Pa (2 mTorr). The film forming atmosphere was argon.

Next, an Al thin film (thickness: about 500 nm) was formed on the surface of the amorphous thin film A by an ion beam sputtering method with a Cu template plate disposed thereon. After the formation of the Al thin film, the template plate was removed, and Fe ions were implanted into the surface of the thin film A using the patterned Al thin film as a mask. Fe ions were implanted under the conditions of 80 keV and 2 × 10 ¹⁵ / cm ² . The Fe concentration in the ion implantation region was about 1 atomic% by the implantation of Fe ions.

After removing the Al thin film by HNO ₃ : H ₃ PO ₄ : CH ₃ COOH = 1: 4: 15 (volume ratio), the amorphous thin film A was irradiated with an electron beam. The electron beam was irradiated at an irradiation intensity of 1 × 10 ¹⁴ / cm ² · sec using an electron beam accelerated at 60 kV−0.3 mA in an atmosphere reduced to 1.3 × 10 ⁻³ Pa. The apparatus used for the electron beam irradiation is an electron beam irradiation tube (USHIO “Min-EB”). The electron beam was passed through the Si window to reduce the energy of the electron beam by about 10 to 20%, and the carbon-based amorphous thin film A was collectively exposed in a scattered state. The distance between the Si window and the thin film A was 15 mm. The irradiation time was 30 minutes to 11 hours. The temperature rise of the thin film A accompanying the electron beam irradiation was saturated at 453 K according to measurement using a thermocouple, and this saturation took 30 minutes.

  FIG. 5 shows changes in the Raman profile associated with electron beam irradiation in the ion implantation region. As estimated from the change in the Raman profile, graphite clusters having a particle diameter exceeding 10 nm were generated in the film. In FIG. 6, the result of having observed the cross section of the thin film with the transmission electron microscope (TEM) before and behind electron beam irradiation is shown. It was confirmed that Fe was agglomerated to form clusters by electron beam irradiation, and these clusters were diffused to the surface.

  A carbon-based amorphous thin film B having a Fe concentration of about 15 atomic% was separately prepared and irradiated with an electron beam in the same manner as described above. 7A to 7C show the results of observation of the change in the structure of the thin film B by electron beam irradiation using a transmission electron microscope (TEM). By the electron beam irradiation, Fe aggregates to form clusters, and these clusters diffuse to the surface. In FIG.7 (c) (irradiation time 5 hours 30 minutes), the area | region where Fe does not exist inside the thin film B appeared.

  The graphite structure produced in the thin film B by electron beam irradiation was observed by TEM. This observation was performed after removing the surface layer of the thin film B containing Fe clusters with 3% nital. The results are shown in FIGS. 8 (a) and (c). FIGS. 8B and 8D are enlarged observation results of portions surrounded by circles in FIGS. 8A and 8C, respectively. On the thin film B, an onion-like graphite structure (FIGS. 8A and 8B) and a plate-like graphite structure (FIGS. 8C and 8D) were observed. The former was conspicuously observed by short irradiation of about 1 hour, and the latter was conspicuously recognized by irradiation exceeding 5 hours.

  Although the size of these graphite clusters depends on the irradiation time, it is about 1 to 10 nm for the onion-like structure, about 20 nm at the maximum for the c-axis direction for the plate-like structure, and the in-plane direction of the basal plane perpendicular to this Reached about 30 nm. The plate-like structure had a tendency that the c-axis was oriented in the film surface direction.

  When the electron beam is irradiated to such an extent that a plate-like structure appears, three structures are produced: an amorphous carbon matrix in which the in-plane correlation distance is less than 2 nm, and an onion shape in which the in-plane correlation distance is 2 to 5 nm. Structures, nanographite structures, and plate-like structures with in-plane correlation distances exceeding 10 nm were observed.

  On the other hand, in the region formed so that no Fe atom was present, the formation of graphite clusters exceeding 2 nm was not observed even when observed by TEM.

  FIG. 9 shows the change in the Raman profile accompanying electron beam irradiation in the region where the film was formed so that Fe atoms exist. With the irradiation of the electron beam, two peaks (D peak and G peak) due to the graphite cluster became prominent, and the G peak shifted to the high frequency side.

  FIG. 10 is a cross-sectional TEM image of a carbon-based thin film formed in the same manner as described above. Fe clusters were generated in the region where Fe ions were implanted, but no Fe clusters were generated in the region where the implantation of Fe ions was prevented by masking.

  FIG. 11 shows the change in the Raman spectrum before and after the electron beam irradiation for the carbon-based thin film shown in FIG. From the Raman profile of FIG. 11, it was confirmed that a graphite cluster having a particle diameter of 10 nm or more was generated in the region into which Fe ions were implanted after the electron beam irradiation. On the other hand, in the region where no Fe ions were implanted, the particle size of the graphite cluster remained at 2 nm or less even after electron beam irradiation.

  From the results of FIGS. 10 and 11, it can be confirmed that a graphite cluster can be generated in an arbitrary region of the carbon-based thin film by forming an arbitrary pattern by masking on the carbon-based thin film. Since the characteristics of an arbitrary region of the carbon-based amorphous film can be changed, the applicable range according to the present invention is extremely wide.

The conditions for implanting Fe ions into the carbon-based thin film shown in FIGS. 10 and 11 are 80 keV and 3.6 × 10 ¹⁶ / cm ² . The electron beam irradiation conditions were the same as described above.

  An experiment similar to the above was performed using Co and Ni instead of Fe. Even when implanted metal atoms were present, the formation of onion-like and plate-like graphite structures was confirmed, and ions were present. In the non-treated region, the formation of graphite clusters exceeding 2 nm was not observed. However, the formation of a plate-like graphite structure was most noticeable when Fe was present.

Moreover, when the same experiment was performed by changing the amount of Fe ions implanted in the range of 10 ¹³ to 2 × 10 ¹⁵ / cm ² , the particle size of the graphite clusters formed varied depending on the amount of Fe ions implanted. FIG. 12 shows a part of the result. Fe ion implantation conditions were (a) 60 keV, 4 × 10 ¹³ / cm ² , (b) 80 keV, 5 × 10 ¹⁴ / cm ² , (c) 80 keV, 2 × 10 ¹⁵ / cm ² . As estimated from changes in the Raman profile, the carbon-based thin film (a) produced graphite clusters with a particle size of about 1.5 nm, and the carbon-based thin film (b) produced graphite clusters with a particle size of about 1.5 nm. On the other hand, in the carbon-based thin film (c), graphite clusters having a particle diameter of 10 nm or more were generated. Examining together with other results, it was found that an injection amount of 1 × 10 ¹⁵ / cm ² or more is desirable for the formation of graphite clusters having a particle size of 10 nm or more.

  Further, instead of the electron beam irradiation, energy was supplied to the amorphous thin film by heat treatment. This experiment also confirmed the formation of graphite clusters. In the heat treatment, the temperature rising rate was 10 K / min, the maximum temperature was 573 K to 1000 K, and the holding time at the maximum temperature was 10,000 to 40000 seconds. By the heat treatment at a maximum temperature of 750 K or more, it was confirmed that graphite clusters having a particle size exceeding 2 nm were formed in the ion implantation region. Also in this case, the formation of graphite clusters having a particle size exceeding 2 nm could not be confirmed in the non-ion-implanted region.

  According to the present invention, it is possible to provide a carbon-based thin film in which regions having different electrical, optical, and mechanical properties are arranged at desired positions in the plane of the thin film. This thin film has characteristics applicable to various electronic devices, optical devices, and wear-resistant members, for example, as an interlayer insulating film or the like through which a conductor penetrates in the thickness direction.

It is a partial cutaway perspective view for showing one process in an example of the manufacturing method of the present invention. It is a partial cutaway perspective view for showing one process performed following the process of FIG. FIG. 3 is a partially cutaway perspective view for showing a carbon-based thin film obtained through the steps shown in FIGS. 1 and 2. It is a partial cutaway perspective view for showing another example of the carbon-based thin film of the present invention. It is a spectrum which shows the measurement result of the carbon-type thin film by the Raman spectroscopy before and after electron beam irradiation. It is a cross-sectional TEM image of the thin film before (a) electron beam irradiation and after (b) irradiation. It is a cross-sectional TEM image showing a state in which metal (Fe) ion clusters are diffused to the surface by electron beam irradiation, (a) is 300 seconds after electron beam irradiation, (b) is 3600 seconds after ( c) shows the state after 19800 seconds. It is a plane TEM image which shows the result of having observed the graphite cluster formed by irradiation of an electron beam, (a) and the enlarged photograph (b) are the observation results after 10000 seconds of electron beam irradiation, (c) And (d) which is the enlarged photograph is an observation result after 20000 seconds of electron beam irradiation. It is a spectrum which shows another example of the measurement result of the carbon-type thin film by the Raman spectroscopy before and after electron beam irradiation. It is a cross-sectional TEM image of the carbon-based thin film after electron beam irradiation in the vicinity of the boundary between the masking region (Fe non-implanted region) and the non-masking region (Fe implanted region). It is a spectrum which shows the measurement result by the Raman spectroscopy before the electron irradiation about the carbon-type thin film shown in FIG. It is a spectrum which shows the measurement result by the Raman spectroscopy before and after electron irradiation about the carbon-type thin film measured by changing the implantation conditions of Fe ions.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Carbon type thin film 11 1st area | region 12 2nd area | region 15 Carbon type amorphous thin film 30 Substrate 31 Mask 32 Ion 33 Electron beam 51 First in-plane direction 52 Second in-plane direction

Claims (22)

A first region comprising graphite clusters having a particle size greater than 2 nm;
A second region not containing a graphite cluster having a particle size exceeding 2 nm,
A carbon-based thin film in which the first region and the second region are exposed on the surface, and at least one condition selected from the following a) and b) is satisfied.
a) The first region contains a metal element.
b) The first region includes at least one selected from a plate-like graphite structure and an onion-like graphite structure as the graphite cluster.   The carbon-based thin film according to claim 1, wherein the metal element is at least one selected from the group consisting of Fe, Co, Ni, Al, Cu and Au.   The carbon-based thin film according to claim 2, wherein the metal element is at least one selected from the group consisting of Fe, Co, and Ni.   The carbon-based thin film according to claim 1, wherein the c-axis of the plate-like graphite structure is oriented in the in-plane direction of the thin film.   The carbon-based thin film according to any one of claims 1 to 4, wherein the first region includes a graphite cluster having a particle size of 5 nm or more.   The carbon-based thin film according to claim 1, wherein the first region has a depth of 10 nm or more from the surface.   The carbon-based thin film according to any one of claims 1 to 6, wherein the thickness in the film thickness direction of the first region and the second region is the same as the thickness of the thin film. The carbon-based thin film according to any one of claims 1 to 7, wherein at least one selected from the following c) and d) is established.
c) One of the regions selected from the first region and the second region is a columnar region surrounded by the other region, and the area of the columnar region on the surface of the carbon-based thin film is 200 nm ² or more. .
d) The first region and the second region have an average diameter that is at least twice as large as an average diameter in a second in-plane direction perpendicular to the first in-plane direction in the first in-plane direction; They are arranged alternately in the second in-plane direction. By implanting metal element ions into a part of the thin film from the surface of the carbon-based amorphous thin film, a first region containing the metal element and a second region not containing the metal element are formed in the thin film. And a process of
By supplying energy to at least the first region, the growth of graphite clusters in the second region is suppressed to such an extent that the particle size of the cluster is 2 nm or less, and the particle size exceeds 2 nm in the first region. Forming a graphite cluster; and a method for producing a carbon-based thin film.   The method for producing a carbon-based thin film according to claim 9, wherein the metal element is at least one selected from the group consisting of Fe, Co, Ni, Al, Cu, and Au.   The method for producing a carbon-based thin film according to claim 10, wherein the metal element is at least one selected from the group consisting of Fe, Co, and Ni.   The method for producing a carbon-based thin film according to claim 9, wherein the ions are implanted from the surface in a state where the surface of the thin film is partially masked. Injection amount of the ions, method of producing a carbon-based thin film according to any one of 1 × 10 ¹⁵ / cm ² or more at which claims 9 to 12.   The method for producing a carbon-based thin film according to claim 9, wherein energy is supplied to the first region and the second region.   The method for producing a carbon-based thin film according to any one of claims 9 to 14, wherein at least one selected from a plate-like graphite structure and an onion-like graphite structure is formed as the graphite cluster in the first region.   The method for producing a carbon-based thin film according to any one of claims 9 to 15, wherein a graphite cluster having a particle size of 5 nm or more is formed in the first region.   The manufacturing method of the carbon-type thin film of any one of Claims 9-16 which supplies energy by irradiating an electron beam. The method for producing a carbon-based thin film according to claim 17, wherein the electron beam is irradiated with an intensity of 1 × 10 ¹⁹ / cm ² · sec or less.   The method for producing a carbon-based thin film according to any one of claims 9 to 16, wherein energy is supplied by heating the thin film.   The method for producing a carbon-based thin film according to claim 19, wherein the thin film is heated to a temperature of 600 to 1000K.   21. The method according to claim 9, further comprising the step of removing the metal atoms existing in the vicinity of the surface after supplying the energy until the metal atoms derived from the ions are diffused and exist near the surface of the thin film. The manufacturing method of the carbon-type thin film of any one.   The method for producing a carbon-based thin film according to claim 21, wherein the step of removing the metal atoms is a step of removing a surface layer of the thin film by dry etching or wet etching.