WO2017213045A1 - Nitrogen-doped graphene film and method for producing same - Google Patents

Nitrogen-doped graphene film and method for producing same Download PDF

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WO2017213045A1
WO2017213045A1 PCT/JP2017/020603 JP2017020603W WO2017213045A1 WO 2017213045 A1 WO2017213045 A1 WO 2017213045A1 JP 2017020603 W JP2017020603 W JP 2017020603W WO 2017213045 A1 WO2017213045 A1 WO 2017213045A1
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nitrogen
graphene film
doped graphene
plasma
partial pressure
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French (fr)
Japanese (ja)
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侑揮 沖川
貴壽 山田
正統 石原
雅考 長谷川
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国立研究開発法人産業技術総合研究所
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Priority to JP2018522453A priority Critical patent/JP6562331B2/en
Publication of WO2017213045A1 publication Critical patent/WO2017213045A1/en

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/02104—Forming layers
    • H01L21/02365—Forming inorganic semiconducting materials on a substrate
    • H01L21/02367—Substrates
    • H01L21/0237—Materials
    • H01L21/02425—Conductive materials, e.g. metallic silicides
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B32/00—Carbon; Compounds thereof
    • C01B32/15—Nano-sized carbon materials
    • C01B32/182—Graphene
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C16/00—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes
    • C23C16/22—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the deposition of inorganic material, other than metallic material
    • C23C16/26—Deposition of carbon only
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/02104—Forming layers
    • H01L21/02365—Forming inorganic semiconducting materials on a substrate
    • H01L21/02518—Deposited layers
    • H01L21/02521—Materials
    • H01L21/02524—Group 14 semiconducting materials
    • H01L21/02527—Carbon, e.g. diamond-like carbon
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/02104—Forming layers
    • H01L21/02365—Forming inorganic semiconducting materials on a substrate
    • H01L21/02518—Deposited layers
    • H01L21/02587—Structure
    • H01L21/0259—Microstructure
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/02104—Forming layers
    • H01L21/02365—Forming inorganic semiconducting materials on a substrate
    • H01L21/02612—Formation types
    • H01L21/02617—Deposition types
    • H01L21/0262—Reduction or decomposition of gaseous compounds, e.g. CVD
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/02104—Forming layers
    • H01L21/02365—Forming inorganic semiconducting materials on a substrate
    • H01L21/02518—Deposited layers
    • H01L21/0257—Doping during depositing
    • H01L21/02573—Conductivity type
    • H01L21/02576—N-type

Definitions

  • the present invention relates to a nitrogen-doped graphene film in which the substitution position of nitrogen atoms is controlled and a method for producing the same.
  • a conductive planar crystal composed of SP 2 bonded carbon atoms is called a graphene film.
  • the graphene film is described in detail in Non-Patent Document 1.
  • a graphene film is a basic unit of crystalline carbon films of various forms. Examples of crystalline carbon films composed of graphene films include single-layer graphene using a single graphene film, nanographene that is a laminate of several to ten nanometer-sized graphene films, and several to several tens of layers. There are carbon nanowalls (see Non-Patent Document 2) in which a graphene film laminate of about one layer is oriented at an angle close to perpendicular to the substrate surface.
  • a crystalline carbon film composed of a graphene film has high mobility, and is expected to be used as a high-frequency device.
  • a crystalline carbon film composed of a graphene film has high light transmittance, and thus is expected to be used as a transparent conductive film or a transparent electrode.
  • a method for producing a graphene film a peeling method from natural graphite, a silicon detaching method by high-temperature heat treatment of silicon carbide, and a method for forming on various metal surfaces have been developed so far.
  • Electronic devices using a crystalline carbon film composed of a graphene film have been studied for various industrial uses. For this reason, the advent of a film forming method capable of forming a large-area graphene film with high throughput is desired.
  • Non-Patent Document 3 A method for forming a graphene film on a copper foil surface by chemical vapor deposition (CVD) is known (see Non-Patent Document 3 and Non-Patent Document 4).
  • the microwave surface wave plasma CVD method can form a graphene film at a low temperature and in a short time, so that it can be applied to a substrate having low heat resistance such as plastic.
  • the production of electronic devices is expected.
  • nitrogen-doped graphene films in which carbon atoms of graphene films are replaced with nitrogen atoms has been actively conducted (see Non-Patent Document 6 and Non-Patent Document 7).
  • Nitrogen-doped graphene films have features not found in conventional graphene films, such as semiconductor applications due to the formation of band gaps and platinum substitute metals that promote oxidation-reduction reactions (applications for battery electrodes).
  • the substitution positions of nitrogen atoms in nitrogen-doped graphene can be roughly classified into three types. That is, the Graphitic type in which the carbon atom at the center of three six-membered rings is substituted with a nitrogen atom, the Pyridine type in which the carbon atom at the end of the six-membered ring is substituted with a nitrogen atom (pyridine type), the end of the six-membered ring Three types of Pyrrolic nitrogen-doped graphene films in which carbon atoms are substituted with nitrogen atoms and become five-membered rings are considered. It has been found that the characteristics of the nitrogen-doped graphene film vary greatly depending on the nitrogen atom substitution position.
  • Non-Patent Document 6 it has been reported that pyridinic-type nitrogen-doped graphene easily promotes a redox reaction (see Non-Patent Document 6).
  • a method for producing a nitrogen-doped graphene film As a method for producing a nitrogen-doped graphene film, a method of irradiating a graphite containing a nitrogen raw material with plasma, a method of adding a nitrogen source gas during CVD graphene synthesis, or the like is known. Considering future industrial applications, it is important to have a synthesis technique that can obtain a large-area nitrogen-doped graphene film at high speed. If single control of the substitution position of nitrogen atoms becomes possible, a nitrogen-doped graphene film can be separately synthesized depending on the application. Therefore, further development of application of nitrogen-doped graphene film is expected.
  • Non-patent Document 6 It has been reported that Pyridine-type nitrogen atom substitution occurs selectively by reacting NH 3 with patterned HOPG (Highly oriented pyrolytic graphite) (Non-patent Document 6). However, a technique for synthesizing a nitrogen-doped graphene film having a large area and a controlled nitrogen atom substitution position has not yet been established. The present invention has been made in view of such a current situation, and an object thereof is to synthesize nitrogen-doped graphene having a large area and a controlled nitrogen atom substitution position.
  • the present inventors succeeded in doping nitrogen atoms in the process of synthesizing graphene by plasma CVD in which the amount of impurity gas is controlled. Further, when the field-effect mobility (I D -V GS characteristic) of the synthesized nitrogen-doped graphene film was measured, the electron field-effect mobility was higher than the Hall field-effect mobility. The present invention has been completed based on these findings.
  • the method for producing a nitrogen-doped graphene film of the present invention is a method for producing a nitrogen-doped graphene film in which a nitrogen-containing graphene film is formed on a substrate by irradiating the substrate with a plasma containing hydrocarbons and N 2.
  • the partial pressure of H 2 O that may be contained in the plasma is 0.015 or less of the total pressure of the plasma, and the partial pressure of O 2 that may be contained in the plasma is 0.0 of the total pressure of the plasma. 002 or less.
  • hydrocarbon is CH 4
  • the partial pressure of H 2 O is preferably at most 0.35 of the partial pressures of CH 4 in the plasma.
  • the partial pressure of N 2 in the plasma is preferably 0.38 to 0.68 of the partial pressure of CH 4 in the plasma.
  • the partial pressure of N 2 in the plasma is 0.58 to 0.68 of the partial pressure of CH 4 in the plasma.
  • a base material containing copper as a main component is placed in a vacuum chamber, and the inside of the vacuum chamber is cleaned with H 2 plasma, and H 2 gas is introduced into the vacuum chamber.
  • H 2 gas is introduced into the vacuum chamber.
  • a raw material gas containing H 2 gas and CH 4 gas is introduced into the vacuum chamber, and the raw material gas is turned into plasma to form nitrogen on the base material.
  • a generation step of generating a doped graphene film In the step of generating the nitrogen-doped graphene film on the substrate, N 2 gas may be introduced into the vacuum chamber from the middle.
  • the nitrogen-doped graphene film of the present invention is a nitrogen-doped graphene film in which some carbon atoms of the graphene skeleton are replaced with nitrogen atoms, and the ratio of the electron field effect mobility to the hole field effect mobility at the same carrier density is 1.15 or more.
  • Another nitrogen-doped graphene film of the present invention is a mainly pyridine type nitrogen-doped graphene film in which some carbon atoms of the graphene skeleton are substituted with nitrogen atoms, and the domain size of the graphene is 10 to 200 nm.
  • a nitrogen-doped graphene film having a large area and a controlled substitution position of nitrogen atoms can be obtained.
  • combines the nitrogen dope graphene film of this invention.
  • the Raman spectrum of the nitrogen dope graphene film of the present invention. 3 is a graph showing I D -V GS characteristics of the nitrogen-doped graphene film of the present invention.
  • FIG. 1 schematically shows a plasma CVD apparatus 100 for synthesizing a nitrogen-doped graphene film according to an embodiment of the present invention.
  • the plasma CVD apparatus 100 includes a synthesis chamber unit, a sample stage unit, a gas supply unit, and a mass spectrometry evaluation unit.
  • the synthesis chamber unit includes a vacuum chamber 101, a plasma generator 102, a turbo molecular pump 103 that depressurizes the inside of the vacuum chamber 101, a screw pump 121, and a shutter 112 that prevents direct irradiation of plasma on the base material 115.
  • the vacuum chamber 101 preferably uses an ICF flange or a metal gasket as much as possible to lower the ultimate pressure. In this embodiment, the pressure in the vacuum chamber 101 can be lowered to 2 ⁇ 10 ⁇ 7 Torr. The pressure in the vacuum chamber 101 is preferably lowered to 10 ⁇ 8 Torr or less.
  • the sample stage unit includes a sample stage 113, a sample heating holder 114, a DC power source 116, and a large current conducting wire 117.
  • the sample stage unit is a component that can heat the substrate 115.
  • the sample is heated by Joule heat generated by applying a voltage.
  • the heating method is not particularly limited as long as the outgas from the heating source is small.
  • the sample stage 113 is provided with a metal bellows (not shown), and the height can be freely changed.
  • the base material 115 is mainly made of a catalytic metal.
  • the base material 115 is preferably made of copper, iridium, or platinum in which carbon is hardly dissolved, but the material of the base material 115 is not limited thereto.
  • the base material 115 is preferably made of nickel or iron in which carbon easily dissolves, but the material of the base material 115 is not limited thereto.
  • the sample heating holder 114 sandwiches the base material 115.
  • the sample heating holder 114 has a terminal for supplying power from the DC power source 116.
  • the base of the sample heating holder 114 is an insulator and is preferably made of alumina.
  • the portion sandwiching the base material 115 is preferably made of molybdenum or tantalum that can withstand high temperatures, but the material of the portion sandwiching the base material 115 is not limited thereto.
  • the gas supply unit supplies the nitrogen-doped graphene raw material into the vacuum chamber 101.
  • the H 2 cylinder 104 and the N 2 cylinder 105 are connected to mass flow controllers 107 and 108, respectively, and the flow rate of gas supplied from these cylinders 104 and 105 can be controlled.
  • the CH 4 cylinder 106 is connected with a minute mass flow controller 109 that can control a smaller gas flow rate.
  • gas purification filters 110 and 111 are connected to the H 2 cylinder 104 and the N 2 cylinder 105, respectively.
  • N 2 is a nitrogen source that forms nitrogen-doped graphene. Even when a nitrogen-containing substance such as urea or ammonia is used, nitrogen-doped graphene is expected to be obtained as in the case of using N 2 .
  • CH 4 is a carbon source that forms nitrogen-doped graphene. Even when a carbon-containing substance such as acetylene is used, nitrogen-doped graphene is expected to be obtained as in the case of using CH 4 .
  • the mass spectrometry evaluation unit is a unit for performing gas analysis in plasma.
  • the mass spectrometry evaluation unit includes a mass spectrometer 118, an orifice tube 119, a turbo molecular pump 120, and a screw pump 121.
  • the pressure of the source gas is set to 1 to 100 Pa.
  • the mass spectrometer 118 is used at a pressure of 10 ⁇ 2 Pa or less. Therefore, a differential exhaust system is constructed by providing an orifice tube 119 having an inner diameter of 1 mm and a length of about several centimeters between the mass spectrometer 118 and the vacuum chamber 101. With this differential evacuation system, even if the pressure in the vacuum chamber 101 is 10 Pa, the pressure in the tube near the mass spectrometer 118 can be maintained on the order of 10 ⁇ 3 to 10 ⁇ 4 Pa.
  • a substrate containing a hydrocarbon and N 2 is irradiated to generate a nitrogen-doped graphene film on the substrate.
  • a nitrogen-doped graphene film in which the substitution position of nitrogen atoms is controlled in a large area can be obtained by reducing the amount of impurities H 2 O and O 2 contained in the plasma. This is thought to be because a slight amount of N 2 in the plasma can be controlled by reducing the amount of impurities H 2 O and O 2 in the plasma.
  • H 2 O and O 2 are not included in the plasma, but this is difficult in a vacuum chamber of an actual plasma CVD apparatus.
  • the partial pressure of H 2 O is 0.02 or less of the total plasma pressure
  • the partial pressure of O 2 is The total pressure of the plasma is 0.005 or less.
  • "of H 2 O partial pressure below 0.02 of the total pressure of the plasma” is ""
  • partial pressure / plasma total pressure of H 2 O is 0.02 or less
  • the hydrocarbon is CH 4
  • the partial pressure of H 2 O in the plasma is preferably 1 or less of the partial pressure of CH 4 in the plasma.
  • the partial pressure of N 2 in the plasma is preferably 0.38 to 0.68 of the partial pressure of CH 4 in the plasma.
  • the method for producing a nitrogen-doped graphene film includes a cleaning process, a heating process, and a generation process.
  • the cleaning process the base material 115 containing copper as a main component is placed in the vacuum chamber 101 and the inside of the vacuum chamber 101 is cleaned with H 2 plasma.
  • the heating process the base material 115 is heated by supplying DC power to the base material 115 while introducing H 2 gas into the vacuum chamber 101.
  • a source gas containing H 2 gas and CH 4 gas is introduced into the vacuum chamber 101, and the source gas is turned into plasma to generate a nitrogen-doped graphene film on the substrate 115.
  • N 2 gas may be introduced into the vacuum chamber from the middle. By controlling the introduction amount of this N 2 gas, selection of the generation of the graphitic, pyridinic, or pyrolytic nitrogen-doped graphene film, that is, the single control of the nitrogen atom substitution position can be performed.
  • the nitrogen-doped graphene film according to the embodiment of the present invention some carbon atoms of the graphene skeleton are replaced with nitrogen atoms, and the ratio of the electron field effect mobility to the hole field effect mobility at the same carrier density is 1.15 or more. It is. Further, in the method for producing a nitrogen-doped graphene film of the present embodiment, a nitrogen-doped graphene film having a wide domain size of graphene can be obtained by more accurately controlling the partial pressure of N 2 and H 2 O in the plasma. In other words, the mainly pyridine-type nitrogen-doped graphene film according to another embodiment of the present invention has a graphene domain size of 10 to 200 nm.
  • a nitrogen-doped graphene film was produced using the plasma CVD apparatus 100 shown in FIG. The following members were used for the plasma CVD apparatus 100.
  • Vacuum chamber 101 manufactured by Techno Support Co., Ltd.
  • Plasma generator 102 Dainippon Screen Mfg. Co., Ltd. inductively coupled plasma (ICP) generator
  • Turbo molecular pump 103 Pfeiffer TC400 DC power supply 116: ZX-400LA from Takasago Works Screw pump 121: V060H of ANELVA Mass flow controllers 107 and 108: SEC-E40 from Horiba Trace mass flow controller 109: HORIBA, Ltd.
  • a tough pitch copper foil (JX Nippon Mining & Metals) having a thickness of about 4 ⁇ m, which is a catalyst metal, was cut out. And this copper foil was wash
  • the base material 115 was set in the vacuum chamber 101. Then, the inside of the vacuum chamber 101 was depressurized until the pressure reached 10 ⁇ 5 Pa level. Thereafter, a nitrogen-doped graphene film was obtained through three steps: a vacuum chamber cleaning step corresponding to the cleaning step, a substrate heating step corresponding to the heating step, and a plasma irradiation step corresponding to the generation step.
  • Vacuum chamber cleaning process In order to suppress generation of impurity gas from the vacuum chamber 101 in the subsequent plasma irradiation process, the vacuum chamber 101 was cleaned using plasma. In other words, the impurity gas is discharged in advance from the inner wall of the vacuum chamber 101, thereby preventing unintended gas from being mixed into the plasma in the subsequent plasma irradiation step. First, 30 sccm of H 2 was introduced into the vacuum chamber 101 using the mass flow controller 107, and the pressure in the vacuum chamber 101 was adjusted to 10 Pa.
  • high frequency power is supplied into the vacuum chamber 101 in a state where the upper portion of the set base material 115 is covered with the shutter 112 so that the plasma does not directly hit, and the H 2 plasma is generated for 2 minutes. 101 was cleaned. From the mass analysis of the plasma during cleaning, the presence of CH 4 and H 2 O was confirmed immediately after the generation of the plasma, but after that, it was observed that the partial pressure of CH 4 and H 2 O gradually decreased. . After the cleaning was completed, the supply of H 2 gas was stopped, and the pressure was reduced until the pressure in the vacuum chamber 101 reached the 10 ⁇ 5 Pa level.
  • the base material 115 was a square having a length of 16 mm and a width of 16 mm.
  • the area of the nitrogen-doped graphene film of this example formed on the entire surface of the substrate 115 was equal to or larger than the reported area of the nitrogen-doped graphene film.
  • FIG. 2 shows the results of mass spectrometry in the plasma irradiation process.
  • FIG. 2A shows the case where the N 2 gas flow rate is 0 sccm
  • FIG. 2B shows the case where the N 2 gas flow rate is 0.2 sccm.
  • the introduction of CH 4 gas was started 20 seconds before the plasma generation, and the introduction was stopped 20 seconds after the plasma disappeared. Further, the introduction of N 2 gas was performed only for the last one minute among the three minutes during which plasma was generated.
  • N 2 was contained in the plasma without introducing N 2 gas into the vacuum chamber 101.
  • N 2 in this plasma is considered to be due to N 2 gas of inevitable impurities present in the vacuum chamber 101 after the substrate heating step. Therefore, a nitrogen-doped graphene film was obtained without introducing N 2 gas into the vacuum chamber 101. Further, it was confirmed that the N 2 partial pressure was increased by introducing N 2 gas as shown in FIG.
  • the total plasma pressure (approximately equivalent to the partial pressure of hydrogen) is 9.9 to 10.1 Pa, and the partial pressure of H 2 O is 5.3 ⁇ 10 ⁇ 3 to 8.4 ⁇ 10 ⁇ 3. Pa, the partial pressure of O 2 is 1.4 ⁇ 10 ⁇ 3 to 1.6 ⁇ 10 ⁇ 3 Pa, and the partial pressure of CH 4 is 2.8 ⁇ 10 ⁇ 2 to 4.6 ⁇ 10 ⁇ 2 Pa.
  • the partial pressure of N 2 was 1.9 ⁇ 10 ⁇ 2 to 2.7 ⁇ 10 ⁇ 2 Pa.
  • the partial pressure of H 2 O was 0.015 or less of the total plasma pressure, and the partial pressure of O 2 was 0.002 or less of the total plasma pressure.
  • the partial pressure of H 2 O was 0.35 or less of the partial pressure of CH 4 .
  • the partial pressure of N 2 was 0.38 to 0.68 of the partial pressure of CH 4 .
  • the partial pressure of N 2 was 0.58 to 0.68 of the partial pressure of CH 4 at each time during plasma generation.
  • the nitrogen-doped graphene film obtained in the plasma irradiation step was used as a Si substrate (hereinafter referred to as Si substrate) having a 100 nm thick SiO 2 film formed on the surface.
  • the substrate having SiO 2 formed on the surface thereof is sometimes referred to as “SiO 2 / Si substrate.
  • Si substrate Si substrate
  • SiO 2 / Si substrate Si substrate
  • a 2% by mass anisole solution of polymethyl methacrylate resin (PMMA) was spin-coated at 3000 rpm for 30 seconds on the surface of a nitrogen-doped graphene film / copper foil.
  • the copper foil was removed by etching using 0.5 mol / L ammonium persulfate to obtain a PMMA / nitrogen-doped graphene film.
  • the PMMA / nitrogen-doped graphene film was superposed on the SiO 2 / Si substrate so that the nitrogen-doped graphene film and the SiO 2 film were in contact with each other. And it infiltrated with acetone and removed PMMA. Thereafter, annealing was performed at 400 ° C. and a pressure of 100 Pa for 2 hours while introducing 10 sccm of argon and hydrogen into the quartz tube furnace to obtain a nitrogen-doped graphene film / SiO 2 / Si substrate.
  • FIG. 3A is a Raman spectrum of a nitrogen-doped graphene film manufactured without introducing N 2 gas into the vacuum chamber 101 in the plasma irradiation process.
  • FIG. 3B is a Raman spectrum of a nitrogen-doped graphene film manufactured by introducing N 2 gas into the vacuum chamber 101 by 0.2 sccm in the plasma irradiation process.
  • FIG. 3C is a Raman spectrum of a nitrogen-doped graphene film produced by introducing 0.4 sccm of N 2 gas into the vacuum chamber 101 in the plasma irradiation process.
  • the graphene domain size La obtained from the result of FIG. 3A is estimated to be about 38 to about 53 nm.
  • the domain size L a of the graphene is estimated to be about 37 to about 53 nm.
  • the nitrogen-doped graphene film in FIG. 3A is presumed to be mainly a pyridine type nitrogen-doped graphene film.
  • a pyridine-type nitrogen-doped graphene film having a graphene domain size of 37 to 53 nm was obtained.
  • a device was fabricated as follows in order to measure the electrical conductivity characteristics of the nitrogen-doped graphene film transferred to the Si substrate. Each process is substantially the same as the method described in Patent Document 1. First, a photomask (chrome mask manufactured by Shineisha Co., Ltd.) is used with a photolithographic technique using a contact mask aligner (SUSS MicroTec, MJB4) at a wavelength of 436 nm, an illuminance of about 40 mW / cm 2 and an exposure time of 2 seconds Then, the nitrogen-doped graphene film was patterned. After exposure, development and baking were performed to form a photoresist with a predetermined pattern on a nitrogen-doped graphene film / SiO 2 / Si substrate to obtain a sample.
  • a photomask chrome mask manufactured by Shineisha Co., Ltd.
  • SUSS MicroTec, MJB4 contact mask aligner
  • the excess nitrogen-doped graphene film on this sample was removed. That is, the pressure in the quartz chamber of the plasma asher was set to 100 Pa, and plasma was generated at an output of 200 W for 5 minutes while introducing O 2 gas at 130 sccm. Thereafter, acetone was infiltrated into the sample to remove the resist, and a nitrogen-doped graphene film existing in a predetermined pattern on the SiO 2 / Si substrate was obtained.
  • a contact electrode composed of gold / nickel was formed in a predetermined pattern on the nitrogen-doped graphene film by metal deposition using a photolithography technique and a vacuum deposition apparatus (manufactured by Eiko Engineering Co., Ltd.).
  • the thickness of the deposited metal was controlled by a crystal oscillator thickness monitor.
  • the photoresist of the sample was removed using acetone. Thereafter, while introducing Ar gas 95 sccm and H 2 gas 5 sccm into the quartz tube furnace, annealing was performed at a pressure of 100 Pa and a temperature of 300 ° C. for 3 hours to remove a resist residue on the device surface, thereby obtaining a device sample.
  • the conductivity (S) of the nitrogen-doped graphene film is calculated.
  • the conductivity (S) -V GS (V) characteristic is obtained by sweeping the back surface voltage (gate voltage: V GS ) from ⁇ 15 V to 15 V while applying V DS .
  • FIG. 4A shows the electric conduction characteristics of a nitrogen-doped graphene film manufactured without introducing N 2 gas into the vacuum chamber 101 in the plasma irradiation step.
  • the absolute value of the slope (transconductance) of the graph is the same in the electron (on the right side of the Dirac point) portion and the hole (on the left side of the Dirac point) portion.
  • the absolute value of the inclination on the electron side was larger than the absolute value of the inclination on the hole side. This means that the electron field effect mobility of the nitrogen-doped graphene film of this example is higher than the hole field effect mobility.
  • FIG. 4B shows the electric conduction characteristics when N 2 gas is introduced into the vacuum chamber 101 by 0.2 sccm in the plasma irradiation step.
  • FIG. 4C shows electrical conduction characteristics when N 2 gas is introduced into the vacuum chamber 101 at 0.4 sccm in the plasma irradiation step. It was observed that the absolute value of the inclination on the electron side and the absolute value of the inclination on the hole side became approximately the same as the amount of N 2 gas introduced was increased.
  • FIG. 5 shows the ratio of the electron field effect mobility to the Hall field effect mobility measured for a plurality of device samples.
  • the electron field effect mobility and the Hall field mobility were calculated by the following equations.
  • ⁇ FE 1 / en ⁇
  • n C ox (V G -V Dirac)
  • mu FE field-effect mobility e is the charge amount
  • n carrier density
  • [rho resistivity
  • Cox oxide capacitance
  • V G is the gate voltage
  • V Dirac the voltage value of the Dirac point. Note that a fixed value of 2 ⁇ 10 12 cm ⁇ 2 was used as the carrier density when calculating the field effect mobility.
  • the ratio of the electron field effect mobility and the hole field effect mobility approaches 1 as the flow rate of N 2 gas introduced into the vacuum chamber 101 in the plasma irradiation process increases.
  • the reference sample (Ref.) Of FIG. 5 is a measurement result about the graphene (made by a graphene platform company) synthesize
  • Device fabrication and electrical property evaluation methods are the same as in this example.
  • a nitrogen-doped graphene film having a ratio of the electron field effect mobility to the hole field effect mobility at the same carrier density of 1.15 or more was obtained (N 2 : 0 sccm and 0.2 sccm).
  • FIG. 7A shows the electric conduction characteristics of a nitrogen-doped graphene film manufactured without introducing N 2 gas in the plasma irradiation step by x marks.
  • FIG. 7B shows the electric conduction characteristics of a nitrogen-doped graphene film produced by introducing 0.2 sccm of N 2 gas with x marks.

Abstract

According to the present invention, a nitrogen-doped graphene film which has a large area, while being controlled with respect to the position of substitution of a nitrogen atom is produced. A method for producing a nitrogen-doped graphene film according to the present invention forms a nitrogen-doped graphene film on a base by irradiating the base with a plasma that contains CH4 and N2. The partial pressure of H2O which is sometimes contained in the plasma is 0.015 or less of the total pressure of the plasma; the partial pressure of O2 which is sometimes contained in the plasma is 0.002 or less of the total pressure of the plasma; and the partial pressure of H2O is 0.35 or less of the partial pressure of CH4 in the plasma.

Description

窒素ドープグラフェン膜とその製造方法Nitrogen-doped graphene film and manufacturing method thereof
　本発明は、窒素原子の置換位置が制御された窒素ドープグラフェン膜とその製造方法に関するものである。 The present invention relates to a nitrogen-doped graphene film in which the substitution position of nitrogen atoms is controlled and a method for producing the same.
　ＳＰ２結合した炭素原子から構成される導電性の平面状結晶は、グラフェン膜と呼ばれている。グラフェン膜については、非特許文献１に詳述されている。グラフェン膜は、様々な形態の結晶性炭素膜の基本単位である。グラフェン膜から構成される結晶性炭素膜の例としては、一層のグラフェン膜による単層グラフェン、ナノメートルサイズのグラフェン膜の数層から十層程度の積層体であるナノグラフェン、および数層から数十層程度のグラフェン膜積層体が基材面に対して垂直に近い角度で配向するカーボンナノウォール（非特許文献２参照）などがある。 A conductive planar crystal composed of SP 2 bonded carbon atoms is called a graphene film. The graphene film is described in detail in Non-Patent Document 1. A graphene film is a basic unit of crystalline carbon films of various forms. Examples of crystalline carbon films composed of graphene films include single-layer graphene using a single graphene film, nanographene that is a laminate of several to ten nanometer-sized graphene films, and several to several tens of layers. There are carbon nanowalls (see Non-Patent Document 2) in which a graphene film laminate of about one layer is oriented at an angle close to perpendicular to the substrate surface.
　グラフェン膜から構成される結晶性炭素膜は、高い移動度を持つことから、高周波デバイスとしての利用が期待されている。また、グラフェン膜から構成される結晶性炭素膜は、高い光透過率を持つことから、透明導電膜や透明電極としての利用が期待されている。グラフェン膜の製造方法として、天然黒鉛からの剥離法、炭化ケイ素の高温熱処理によるケイ素の脱離法、および様々な金属表面への形成法などが、これまでに開発されている。グラフェン膜から構成される結晶性炭素膜を用いた電子デバイスは、多岐にわたる工業的な利用が検討されている。このため、高いスループットで大面積のグラフェン膜が形成できる成膜方法の出現が望まれている。 A crystalline carbon film composed of a graphene film has high mobility, and is expected to be used as a high-frequency device. In addition, a crystalline carbon film composed of a graphene film has high light transmittance, and thus is expected to be used as a transparent conductive film or a transparent electrode. As a method for producing a graphene film, a peeling method from natural graphite, a silicon detaching method by high-temperature heat treatment of silicon carbide, and a method for forming on various metal surfaces have been developed so far. Electronic devices using a crystalline carbon film composed of a graphene film have been studied for various industrial uses. For this reason, the advent of a film forming method capable of forming a large-area graphene film with high throughput is desired.
　化学気相合成法（ＣＶＤ）による銅箔表面へのグラフェン膜の形成法が知られている（非特許文献３および非特許文献４参照）。その中の一つであるマイクロ波表面波プラズマＣＶＤ法（非特許文献５参照）は、低温かつ短時間でグラフェン膜を成膜することができるため、プラスチックなどの耐熱性が低い基板上への電子デバイスの作製が期待される。また近年、グラフェン膜の炭素原子を窒素原子に置換する窒素ドープグラフェン膜の研究が盛んに行われている（非特許文献６および非特許文献７参照）。窒素ドープグラフェン膜は、バンドギャップが形成されることによる半導体応用や、酸化還元反応を促進するプラチナ代替金属（電池の電極応用）など、これまでのグラフェン膜にはない特長を有している。 A method for forming a graphene film on a copper foil surface by chemical vapor deposition (CVD) is known (see Non-Patent Document 3 and Non-Patent Document 4). One of them, the microwave surface wave plasma CVD method (see Non-Patent Document 5), can form a graphene film at a low temperature and in a short time, so that it can be applied to a substrate having low heat resistance such as plastic. The production of electronic devices is expected. In recent years, research on nitrogen-doped graphene films in which carbon atoms of graphene films are replaced with nitrogen atoms has been actively conducted (see Non-Patent Document 6 and Non-Patent Document 7). Nitrogen-doped graphene films have features not found in conventional graphene films, such as semiconductor applications due to the formation of band gaps and platinum substitute metals that promote oxidation-reduction reactions (applications for battery electrodes).
　窒素ドープグラフェンにおける窒素原子の置換位置は大きく３種類に分類することができる。すなわち、３つの六員環の中心の炭素原子が窒素原子で置換されたＧｒａｐｈｉｔｉｃ型、六員環の端の炭素原子が窒素原子で置換されたＰｙｒｉｄｉｎｉｃ型（ピリジン型）、六員環の端の炭素原子が窒素原子で置換され、さらに五員環になったＰｙｒｒｏｌｉｃ型の３種類の窒素ドープグラフェン膜が考えられている。そして、窒素原子の置換位置によって、窒素ドープグラフェン膜の特性が大きく変わることが分かっている。したがって、窒素ドープグラフェンの産業応用を考える上では、窒素原子の置換位置の単一制御が必要となる。例えば、Ｐｙｒｉｄｉｎｉｃ型の窒素ドープグラフェンは、酸化還元反応を促進しやすいことが報告されている（非特許文献６参照）。 The substitution positions of nitrogen atoms in nitrogen-doped graphene can be roughly classified into three types. That is, the Graphitic type in which the carbon atom at the center of three six-membered rings is substituted with a nitrogen atom, the Pyridine type in which the carbon atom at the end of the six-membered ring is substituted with a nitrogen atom (pyridine type), the end of the six-membered ring Three types of Pyrrolic nitrogen-doped graphene films in which carbon atoms are substituted with nitrogen atoms and become five-membered rings are considered. It has been found that the characteristics of the nitrogen-doped graphene film vary greatly depending on the nitrogen atom substitution position. Therefore, when considering the industrial application of nitrogen-doped graphene, a single control of the substitution position of the nitrogen atom is required. For example, it has been reported that pyridinic-type nitrogen-doped graphene easily promotes a redox reaction (see Non-Patent Document 6).
特開２０１４－０８６５９２号公報JP 2014-086592 A
　窒素ドープグラフェン膜の作製方法として、黒鉛に窒素原料を含むプラズマを照射する方法や、ＣＶＤグラフェン合成中に窒素源ガスを添加する方法などが知られている。今後の産業応用を考えると、大面積の窒素ドープグラフェン膜が高速で得られる合成技術が重要である。窒素原子の置換位置の単一制御が可能となれば、用途によって窒素ドープグラフェン膜を分別合成することが可能となる。したがって、窒素ドープグラフェン膜の応用の更なる発展が見込まれる。 As a method for producing a nitrogen-doped graphene film, a method of irradiating a graphite containing a nitrogen raw material with plasma, a method of adding a nitrogen source gas during CVD graphene synthesis, or the like is known. Considering future industrial applications, it is important to have a synthesis technique that can obtain a large-area nitrogen-doped graphene film at high speed. If single control of the substitution position of nitrogen atoms becomes possible, a nitrogen-doped graphene film can be separately synthesized depending on the application. Therefore, further development of application of nitrogen-doped graphene film is expected.
　パターン化したＨＯＰＧ（Highly oriented pyrolytic graphite）にＮＨ３を反応させることでＰｙｒｉｄｉｎｉｃ型の窒素原子置換が選択的に起こることが報告されている（非特許文献６）。しかし、大面積かつ窒素原子の置換位置が制御された窒素ドープグラフェン膜の合成技術はまだ確立されていない。本発明は、このような現状に鑑みてなされたものであり、大面積で窒素原子置換位置が制御された窒素ドープグラフェンを合成することを目的とする。 It has been reported that Pyridine-type nitrogen atom substitution occurs selectively by reacting NH 3 with patterned HOPG (Highly oriented pyrolytic graphite) (Non-patent Document 6). However, a technique for synthesizing a nitrogen-doped graphene film having a large area and a controlled nitrogen atom substitution position has not yet been established. The present invention has been made in view of such a current situation, and an object thereof is to synthesize nitrogen-doped graphene having a large area and a controlled nitrogen atom substitution position.
　本発明者らは、上記目的を達成すべく鋭意研究を重ねた結果、不純物ガス量をコントロールしたプラズマＣＶＤにより、グラフェン合成過程で窒素原子をドーピングすることに成功した。また、合成した窒素ドープグラフェン膜の電界効果移動度（ＩＤ－ＶＧＳ特性）を測定したところ、電子電界効果移動度がホール電界効果移動度よりも高かった。本発明はこれらの知見に基づいて完成に至ったものである。 As a result of intensive studies to achieve the above object, the present inventors succeeded in doping nitrogen atoms in the process of synthesizing graphene by plasma CVD in which the amount of impurity gas is controlled. Further, when the field-effect mobility (I D -V GS characteristic) of the synthesized nitrogen-doped graphene film was measured, the electron field-effect mobility was higher than the Hall field-effect mobility. The present invention has been completed based on these findings.
　本発明の窒素ドープグラフェン膜の製造方法は、炭化水素およびＮ２を含有するプラズマを基材に照射して、基材上に窒素ドープグラフェン膜を生成させる窒素ドープグラフェン膜の製造方法であって、プラズマ中に含まれることがあるＨ２Ｏの分圧が、プラズマの全圧の０.０１５以下で、プラズマ中に含まれることがあるＯ２の分圧が、プラズマの全圧の０.００２以下である。 The method for producing a nitrogen-doped graphene film of the present invention is a method for producing a nitrogen-doped graphene film in which a nitrogen-containing graphene film is formed on a substrate by irradiating the substrate with a plasma containing hydrocarbons and N 2. The partial pressure of H 2 O that may be contained in the plasma is 0.015 or less of the total pressure of the plasma, and the partial pressure of O 2 that may be contained in the plasma is 0.0 of the total pressure of the plasma. 002 or less.
　本発明の窒素ドープグラフェン膜の製造方法において、炭化水素がＣＨ４であり、Ｈ2Ｏの分圧が、プラズマ中のＣＨ４の分圧の０.３５以下であることが好ましい。また、プラズマ中のＮ２の分圧が、プラズマ中のＣＨ４の分圧の０.３８～０.６８であることが好ましい。さらに、プラズマ中のＮ２の分圧が、プラズマ中のＣＨ４の分圧の０.５８～０.６８であることが好ましい。また、基材の温度を６００～７５０℃に維持しながら基材上に窒素ドープグラフェンを生成させることが好ましい。 The method of manufacturing a nitrogen-doped graphene film of the present invention, hydrocarbon is CH 4, the partial pressure of H 2 O is preferably at most 0.35 of the partial pressures of CH 4 in the plasma. Further, the partial pressure of N 2 in the plasma is preferably 0.38 to 0.68 of the partial pressure of CH 4 in the plasma. Further, it is preferable that the partial pressure of N 2 in the plasma is 0.58 to 0.68 of the partial pressure of CH 4 in the plasma. Further, it is preferable to generate nitrogen-doped graphene on the substrate while maintaining the temperature of the substrate at 600 to 750 ° C.
　本発明の他の窒素ドープグラフェン膜の製造方法は、銅を主成分とする基材を真空チャンバーに入れ、Ｈ２プラズマで真空チャンバー内をクリーニングするクリーニング工程と、真空チャンバーにＨ２ガスを導入しながら、基材に直流電力を供給して基材を加熱する加熱工程と、真空チャンバーにＨ２ガスおよびＣＨ４ガスを含む原料ガスを導入し、原料ガスをプラズマ化して基材上に窒素ドープグラフェン膜を生成させる生成工程とを有する。基材上に窒素ドープグラフェン膜を生成させる工程では、真空チャンバーにＮ２ガスを途中から導入してもよい。 In another method of manufacturing a nitrogen-doped graphene film of the present invention, a base material containing copper as a main component is placed in a vacuum chamber, and the inside of the vacuum chamber is cleaned with H 2 plasma, and H 2 gas is introduced into the vacuum chamber. While heating the base material by supplying DC power to the base material, a raw material gas containing H 2 gas and CH 4 gas is introduced into the vacuum chamber, and the raw material gas is turned into plasma to form nitrogen on the base material. And a generation step of generating a doped graphene film. In the step of generating the nitrogen-doped graphene film on the substrate, N 2 gas may be introduced into the vacuum chamber from the middle.
　本発明の窒素ドープグラフェン膜は、グラフェン骨格の一部の炭素原子が窒素原子で置換された窒素ドープグラフェン膜であって、同一キャリア密度におけるホール電界効果移動度に対する電子電界効果移動度の比が１.１５以上である。本発明の他の窒素ドープグラフェン膜は、グラフェン骨格の一部の炭素原子が窒素原子で置換された主にピリジン型の窒素ドープグラフェン膜であって、グラフェンのドメインサイズが１０～２００ｎｍである。 The nitrogen-doped graphene film of the present invention is a nitrogen-doped graphene film in which some carbon atoms of the graphene skeleton are replaced with nitrogen atoms, and the ratio of the electron field effect mobility to the hole field effect mobility at the same carrier density is 1.15 or more. Another nitrogen-doped graphene film of the present invention is a mainly pyridine type nitrogen-doped graphene film in which some carbon atoms of the graphene skeleton are substituted with nitrogen atoms, and the domain size of the graphene is 10 to 200 nm.
　本発明によれば、大面積で窒素原子の置換位置が制御された窒素ドープグラフェン膜が得られる。 According to the present invention, a nitrogen-doped graphene film having a large area and a controlled substitution position of nitrogen atoms can be obtained.
本発明の窒素ドープグラフェン膜を合成するプラズマＣＶＤ装置の断面模式図。The cross-sectional schematic diagram of the plasma CVD apparatus which synthesize | combines the nitrogen dope graphene film of this invention. 本発明の窒素ドープグラフェン膜を合成しているときのプラズマ中の各成分の分圧の経時変化を表すグラフ。The graph showing the time-dependent change of the partial pressure of each component in plasma when synthesizing the nitrogen dope graphene film of the present invention. 本発明の窒素ドープグラフェン膜のラマン分光スペクトル。The Raman spectrum of the nitrogen dope graphene film of the present invention. 本発明の窒素ドープグラフェン膜のＩＤ－ＶＧＳ特性を表すグラフ。3 is a graph showing I D -V GS characteristics of the nitrogen-doped graphene film of the present invention. 本発明の窒素ドープグラフェン膜について、同一キャリア密度におけるホール電界効果移動度に対する電子電界効果移動度の比を表すグラフ。The graph showing the ratio of the electron field effect mobility with respect to the Hall field effect mobility in the same carrier density about the nitrogen dope graphene film of this invention. 本発明の窒素ドープグラフェン膜のＸ線光電子分光スペクトル。The X-ray photoelectron spectroscopy spectrum of the nitrogen dope graphene film of the present invention. 本発明および比較例の窒素ドープグラフェン膜のＩＤ－ＶＧＳ特性を表すグラフ。The graph showing the I D -V GS characteristic of the nitrogen dope graphene film of the present invention and a comparative example.
　以下、本発明の窒素ドープグラフェン膜とその製造方法について、実施形態と実施例に基づいて説明する。重複説明は適宜省略する。なお、２つの数値の間に「～」を記載して数値範囲を表す場合には、この２つの数値も数値範囲に含まれるものとする。 Hereinafter, the nitrogen-doped graphene film of the present invention and the manufacturing method thereof will be described based on embodiments and examples. A duplicate description will be omitted as appropriate. In the case where a numerical range is indicated by describing “˜” between two numerical values, the two numerical values are also included in the numerical range.
　図１は、本発明の実施形態に係る窒素ドープグラフェン膜を合成するプラズマＣＶＤ装置１００を模式的に表したものである。プラズマＣＶＤ装置１００は、合成チャンバーユニットと、試料台ユニットと、ガス供給ユニットと、質量分析評価ユニットを備えている。合成チャンバーユニットは、真空チャンバー１０１と、プラズマ発生装置１０２と、真空チャンバー１０１内を減圧するターボ分子ポンプ１０３と、スクリューポンプ１２１と、プラズマの基材１１５への直接照射を防ぐシャッター１１２を備えている。真空チャンバー１０１は、可能な限りＩＣＦフランジやメタルガスケットを使用して到達圧力を低くすることが好ましい。本実施形態では、真空チャンバー１０１内の圧力は、２×１０－７Ｔｏｒｒまで下げることが可能である。真空チャンバー１０１内の圧力は、１０－８Ｔｏｒｒ以下まで下げられることが好ましい。 FIG. 1 schematically shows a plasma CVD apparatus 100 for synthesizing a nitrogen-doped graphene film according to an embodiment of the present invention. The plasma CVD apparatus 100 includes a synthesis chamber unit, a sample stage unit, a gas supply unit, and a mass spectrometry evaluation unit. The synthesis chamber unit includes a vacuum chamber 101, a plasma generator 102, a turbo molecular pump 103 that depressurizes the inside of the vacuum chamber 101, a screw pump 121, and a shutter 112 that prevents direct irradiation of plasma on the base material 115. Yes. The vacuum chamber 101 preferably uses an ICF flange or a metal gasket as much as possible to lower the ultimate pressure. In this embodiment, the pressure in the vacuum chamber 101 can be lowered to 2 × 10 −7 Torr. The pressure in the vacuum chamber 101 is preferably lowered to 10 −8 Torr or less.
　試料台ユニットは、試料ステージ１１３と、試料加熱ホルダー１１４と、直流電源１１６と、大電流用導線１１７を備えている。試料台ユニットは、基材１１５を加熱できる部品である。本実施形態では電圧を印加することで発生するジュール熱により試料を加熱している。しかし、加熱源からのアウトガスが小さければ、加熱方法は特に制限がない。試料ステージ１１３には、金属ベローズが設けられており（不図示）、高さが自由に変更できる。基材１１５は触媒金属を主材料としている。薄いグラフェンを合成する場合は、炭素が溶けにくい銅、イリジウム、白金で基材１１５を作製することが好ましいが、基材１１５の材料はこれらに制限されない。また、厚いグラフェンを合成する場合は、炭素が溶けやすいニッケルや鉄で基材１１５を作製することが好ましいが、基材１１５の材料はこれらに制限されない。 The sample stage unit includes a sample stage 113, a sample heating holder 114, a DC power source 116, and a large current conducting wire 117. The sample stage unit is a component that can heat the substrate 115. In this embodiment, the sample is heated by Joule heat generated by applying a voltage. However, the heating method is not particularly limited as long as the outgas from the heating source is small. The sample stage 113 is provided with a metal bellows (not shown), and the height can be freely changed. The base material 115 is mainly made of a catalytic metal. In the case of synthesizing thin graphene, the base material 115 is preferably made of copper, iridium, or platinum in which carbon is hardly dissolved, but the material of the base material 115 is not limited thereto. In the case of synthesizing thick graphene, the base material 115 is preferably made of nickel or iron in which carbon easily dissolves, but the material of the base material 115 is not limited thereto.
　試料加熱ホルダー１１４は基材１１５を挟む。試料加熱ホルダー１１４には、直流電源１１６からの電力を供給するための端子が付いている。試料加熱ホルダー１１４の台座は絶縁体であり、アルミナから構成されていることが好ましい。また、基材１１５を挟む箇所は、高温でも耐え得るモリブデンやタンタルで作製されていることが好ましいが、基材１１５を挟む箇所の材料はこれらに制限されない。 The sample heating holder 114 sandwiches the base material 115. The sample heating holder 114 has a terminal for supplying power from the DC power source 116. The base of the sample heating holder 114 is an insulator and is preferably made of alumina. In addition, the portion sandwiching the base material 115 is preferably made of molybdenum or tantalum that can withstand high temperatures, but the material of the portion sandwiching the base material 115 is not limited thereto.
　ガス供給ユニットは、窒素ドープグラフェンの原料を真空チャンバー１０１内に供給する。Ｈ２ボンベ１０４とＮ２ボンベ１０５は、それぞれマスフローコントローラ１０７，１０８と接続されており、これらのボンベ１０４，１０５から供給されるガス流量を制御できる。ＣＨ４ボンベ１０６には、より微量なガス流量をコントロールできる微量マスフローコントローラ１０９が接続されている。また、Ｈ２ＯやＣＯなどの不純物ガスを除去するため、Ｈ２ボンベ１０４とＮ２ボンベ１０５には、それぞれガス精製フィルタ１１０，１１１が接続されている。 The gas supply unit supplies the nitrogen-doped graphene raw material into the vacuum chamber 101. The H 2 cylinder 104 and the N 2 cylinder 105 are connected to mass flow controllers 107 and 108, respectively, and the flow rate of gas supplied from these cylinders 104 and 105 can be controlled. The CH 4 cylinder 106 is connected with a minute mass flow controller 109 that can control a smaller gas flow rate. In order to remove impurity gases such as H 2 O and CO, gas purification filters 110 and 111 are connected to the H 2 cylinder 104 and the N 2 cylinder 105, respectively.
　Ｎ２は窒素ドープグラフェンを形成する窒素源である。尿素やアンモニアなどの窒素含有物質を用いても、Ｎ２を用いたときと同様に、窒素ドープグラフェンが得られると期待される。また、ＣＨ４は窒素ドープグラフェンを形成する炭素源である。アセチレン等の炭素含有物質を用いても、ＣＨ４を用いたときと同様に、窒素ドープグラフェンが得られると期待される。 N 2 is a nitrogen source that forms nitrogen-doped graphene. Even when a nitrogen-containing substance such as urea or ammonia is used, nitrogen-doped graphene is expected to be obtained as in the case of using N 2 . CH 4 is a carbon source that forms nitrogen-doped graphene. Even when a carbon-containing substance such as acetylene is used, nitrogen-doped graphene is expected to be obtained as in the case of using CH 4 .
　質量分析評価ユニットは、プラズマ中のガス分析を行うためのユニットである。質量分析評価ユニットは、質量分析装置１１８と、オリフィス管１１９と、ターボ分子ポンプ１２０と、スクリューポンプ１２１を備えている。プラズマＣＶＤによる窒素ドープグラフェン膜の合成では、原料ガスの圧力を１～１００Ｐａに設定する。一方、質量分析装置１１８は、圧力１０－２Ｐａ以下で使用する。このため、質量分析装置１１８と真空チャンバー１０１との間に、内径１ｍｍ以内、長さ数ｃｍ程度のオリフィス管１１９を設けて差動排気システムを構築する。この差動排気システムにより、真空チャンバー１０１内の圧力が１０Ｐａであっても、質量分析装置１１８付近の管内の圧力を１０－３～１０－４Ｐａ台に保つことができる。 The mass spectrometry evaluation unit is a unit for performing gas analysis in plasma. The mass spectrometry evaluation unit includes a mass spectrometer 118, an orifice tube 119, a turbo molecular pump 120, and a screw pump 121. In the synthesis of the nitrogen-doped graphene film by plasma CVD, the pressure of the source gas is set to 1 to 100 Pa. On the other hand, the mass spectrometer 118 is used at a pressure of 10 −2 Pa or less. Therefore, a differential exhaust system is constructed by providing an orifice tube 119 having an inner diameter of 1 mm and a length of about several centimeters between the mass spectrometer 118 and the vacuum chamber 101. With this differential evacuation system, even if the pressure in the vacuum chamber 101 is 10 Pa, the pressure in the tube near the mass spectrometer 118 can be maintained on the order of 10 −3 to 10 −4 Pa.
　本発明の実施形態に係る窒素ドープグラフェン膜の製造方法は、炭化水素およびＮ２を含有するプラズマを基材に照射して、基材上に窒素ドープグラフェン膜を生成させる。本実施形態では、プラズマ中に含まれる不純物のＨ２ＯとＯ２の量を少なくすることで、大面積で窒素原子の置換位置が制御された窒素ドープグラフェン膜が得られる。これは、プラズマ中の不純物のＨ２ＯやＯ２の量を少なくすることで、プラズマ中のわずかなＮ２の量がコントロールできるためだと考えられる。 In the method for producing a nitrogen-doped graphene film according to an embodiment of the present invention, a substrate containing a hydrocarbon and N 2 is irradiated to generate a nitrogen-doped graphene film on the substrate. In this embodiment, a nitrogen-doped graphene film in which the substitution position of nitrogen atoms is controlled in a large area can be obtained by reducing the amount of impurities H 2 O and O 2 contained in the plasma. This is thought to be because a slight amount of N 2 in the plasma can be controlled by reducing the amount of impurities H 2 O and O 2 in the plasma.
　プラズマ中にＨ２ＯとＯ２が含まれないことが好ましいが、現実のプラズマＣＶＤ装置の真空チャンバーでは困難である。本実施形態では、プラズマ中にＨ２ＯおよびＯ２が含まれないか、含まれたとしても、Ｈ２Ｏの分圧がプラズマの全圧の０.０２以下で、Ｏ２の分圧がプラズマの全圧の０.００５以下である。ここで、例えば「Ｈ２Ｏの分圧がプラズマの全圧の０.０２以下」とは、「『Ｈ２Ｏの分圧／プラズマの全圧』が０.０２以下」を意味する。 It is preferable that H 2 O and O 2 are not included in the plasma, but this is difficult in a vacuum chamber of an actual plasma CVD apparatus. In this embodiment, even if H 2 O and O 2 are not included in the plasma, the partial pressure of H 2 O is 0.02 or less of the total plasma pressure, and the partial pressure of O 2 is The total pressure of the plasma is 0.005 or less. Here, for example, "of H 2 O partial pressure below 0.02 of the total pressure of the plasma" is "," partial pressure / plasma total pressure of H 2 O "is 0.02 or less" means.
　本実施形態では、炭化水素がＣＨ４であり、プラズマ中のＨ２Ｏの分圧が、プラズマ中のＣＨ４の分圧の１以下であることが好ましい。また、プラズマ中のＮ２の分圧が、プラズマ中のＣＨ４の分圧の０.３８～０.６８であることが好ましい。また、銅を主成分とする基材に窒素ドープグラフェン膜を生成させることが好ましい。また、基材の温度を６００～７５０℃に維持しながら基材上に窒素ドープグラフェンを生成させることが好ましい。 In the present embodiment, the hydrocarbon is CH 4 , and the partial pressure of H 2 O in the plasma is preferably 1 or less of the partial pressure of CH 4 in the plasma. Further, the partial pressure of N 2 in the plasma is preferably 0.38 to 0.68 of the partial pressure of CH 4 in the plasma. Further, it is preferable to form a nitrogen-doped graphene film on a base material mainly composed of copper. Further, it is preferable to generate nitrogen-doped graphene on the substrate while maintaining the temperature of the substrate at 600 to 750 ° C.
　より具体的には、窒素ドープグラフェン膜の製造方法は、クリーニング工程と、加熱工程と、生成工程とを備えている。クリーニング工程では、銅を主成分とする基材１１５を真空チャンバー１０１に入れ、Ｈ２プラズマで真空チャンバー１０１内をクリーニングする。加熱工程では、真空チャンバー１０１にＨ２ガスを導入しながら、基材１１５に直流電力を供給して基材１１５を加熱する。生成工程では、真空チャンバー１０１にＨ２ガスおよびＣＨ４ガスを含む原料ガスを導入し、原料ガスをプラズマ化して基材１１５上に窒素ドープグラフェン膜を生成させる。 More specifically, the method for producing a nitrogen-doped graphene film includes a cleaning process, a heating process, and a generation process. In the cleaning process, the base material 115 containing copper as a main component is placed in the vacuum chamber 101 and the inside of the vacuum chamber 101 is cleaned with H 2 plasma. In the heating process, the base material 115 is heated by supplying DC power to the base material 115 while introducing H 2 gas into the vacuum chamber 101. In the generation step, a source gas containing H 2 gas and CH 4 gas is introduced into the vacuum chamber 101, and the source gas is turned into plasma to generate a nitrogen-doped graphene film on the substrate 115.
　原料ガスにＮ２ガスが含まれていなくても、真空チャンバー１０１内に存在する不可避不純物である微量のＮ２ガスの存在によって、窒素ドープグラフェン膜が生成する。なお、基材上に窒素ドープグラフェン膜を生成させる工程では、真空チャンバーにＮ２ガスを途中から導入してもよい。このＮ２ガスの導入量を制御することで、Ｇｒａｐｈｉｔｉｃ型、Ｐｙｒｉｄｉｎｉｃ型、またはＰｙｒｒｏｌｉｃ型の窒素ドープグラフェン膜の生成の選択が、すなわち窒素原子の置換位置の単一制御ができる。 Even though it does not contain N 2 gas to the raw material gas, the presence of N 2 gas traces is inevitable impurities present in the vacuum chamber 101, a nitrogen-doped graphene film is produced. Note that, in the step of generating the nitrogen-doped graphene film on the substrate, N 2 gas may be introduced into the vacuum chamber from the middle. By controlling the introduction amount of this N 2 gas, selection of the generation of the graphitic, pyridinic, or pyrolytic nitrogen-doped graphene film, that is, the single control of the nitrogen atom substitution position can be performed.
　本発明の実施形態に係る窒素ドープグラフェン膜は、グラフェン骨格の一部の炭素原子が窒素原子で置換され、同一キャリア密度におけるホール電界効果移動度に対する電子電界効果移動度の比が１.１５以上である。また、本実施形態の窒素ドープグラフェン膜の製造方法において、プラズマ中のＮ２およびＨ２Ｏの分圧をより正確に制御すれば、グラフェンのドメインサイズが幅広い窒素ドープグラフェン膜が得られる。すなわち、本発明の他の実施形態に係る主にピリジン型の窒素ドープグラフェン膜は、グラフェンのドメインサイズが１０～２００ｎｍである。 In the nitrogen-doped graphene film according to the embodiment of the present invention, some carbon atoms of the graphene skeleton are replaced with nitrogen atoms, and the ratio of the electron field effect mobility to the hole field effect mobility at the same carrier density is 1.15 or more. It is. Further, in the method for producing a nitrogen-doped graphene film of the present embodiment, a nitrogen-doped graphene film having a wide domain size of graphene can be obtained by more accurately controlling the partial pressure of N 2 and H 2 O in the plasma. In other words, the mainly pyridine-type nitrogen-doped graphene film according to another embodiment of the present invention has a graphene domain size of 10 to 200 nm.
　以下、本発明の窒素ドープグラフェン膜とこの製造方法を実施例に基づいて説明するが、本発明はこの実施例に限定されるものではない。 Hereinafter, the nitrogen-doped graphene film of the present invention and the manufacturing method thereof will be described based on examples, but the present invention is not limited to these examples.
１.窒素ドープグラフェン膜の製造
　図１に示すプラズマＣＶＤ装置１００を用いて、窒素ドープグラフェン膜を製造した。なお、プラズマＣＶＤ装置１００を構成する部材は以下を用いた。
　真空チャンバー１０１：有限会社テクノサポート製
　プラズマ発生装置１０２：大日本スクリーン製造株式会社の誘導結合型プラズマ（ＩＣＰ）発生装置
　ターボ分子ポンプ１０３：ファイファー社のＴＣ４００
　直流電源１１６：高砂製作所のＺＸ－４００ＬＡ
　スクリューポンプ１２１：ＡＮＥＬＶＡ社のＶ０６０Ｈ
　マスフローコントローラ１０７，１０８：堀場製作所のＳＥＣ－Ｅ４０
　微量マスフローコントローラ１０９：堀場製作所のＳＥＣ－Ｚ５１２
　ガス精製フィルタ１１０，１１１：日本インテグリス社のゲートキーパーＣＥ３０ＫＦＨ４Ｒ
　質量分析装置１１８：キャノンアネルバ社のＭ１０１ＱＡ－ＴＤＭ
　ターボ分子ポンプ１２０：ファイファー社のＴＣ６００
　スクリューポンプ１２１：ＡＮＥＬＶＡ社のＶ０６０Ｈ 1. Production of Nitrogen-Doped Graphene Film A nitrogen-doped graphene film was produced using the plasma CVD apparatus 100 shown in FIG. The following members were used for the plasma CVD apparatus 100.
Vacuum chamber 101: manufactured by Techno Support Co., Ltd. Plasma generator 102: Dainippon Screen Mfg. Co., Ltd. inductively coupled plasma (ICP) generator Turbo molecular pump 103: Pfeiffer TC400
DC power supply 116: ZX-400LA from Takasago Works
Screw pump 121: V060H of ANELVA
Mass flow controllers 107 and 108: SEC-E40 from Horiba
Trace mass flow controller 109: HORIBA, Ltd. SEC-Z512
Gas purification filters 110 and 111: Japan Entegris Gatekeeper CE30KFH4R
Mass spectrometer 118: M101QA-TDM from Canon Anelva
Turbo molecular pump 120: Pfeiffer TC600
Screw pump 121: V060H of ANELVA
　まず、触媒金属である厚さ約４μｍのタフピッチ銅箔（ＪＸ日鉱日石金属）を切り出した。そして、この銅箔を５質量％硫酸で洗浄して、表面の酸化防止剤ベンゾトリアゾールを除去して銅箔の基材１１５を得た。つぎに、基材１１５を真空チャンバー１０１内にセットした。そして、圧力が１０－５Ｐａ台になるまで真空チャンバー１０１内を減圧した。その後、クリーニング工程に該当する真空チャンバークリーニング工程、加熱工程に該当する基材加熱工程、および生成工程に該当するプラズマ照射工程の三工程を経て、窒素ドープグラフェン膜を得た。 First, a tough pitch copper foil (JX Nippon Mining & Metals) having a thickness of about 4 μm, which is a catalyst metal, was cut out. And this copper foil was wash | cleaned with 5 mass% sulfuric acid, the antioxidant benzotriazole of the surface was removed, and the base material 115 of copper foil was obtained. Next, the base material 115 was set in the vacuum chamber 101. Then, the inside of the vacuum chamber 101 was depressurized until the pressure reached 10 −5 Pa level. Thereafter, a nitrogen-doped graphene film was obtained through three steps: a vacuum chamber cleaning step corresponding to the cleaning step, a substrate heating step corresponding to the heating step, and a plasma irradiation step corresponding to the generation step.
（１）真空チャンバークリーニング工程
　後のプラズマ照射工程で真空チャンバー１０１から不純物ガスが発生するのを抑制するため、プラズマを用いて真空チャンバー１０１をクリーニングした。すなわち、真空チャンバー１０１の内壁から不純物ガスを予め放出させることで、後のプラズマ照射工程で意図しないガスがプラズマ中に混入するのを抑える。まず、マスフローコントローラ１０７を用いてＨ２３０ｓｃｃｍを真空チャンバー１０１内に導入し、真空チャンバー１０１内の圧力を１０Ｐａに調整した。 (1) Vacuum chamber cleaning process In order to suppress generation of impurity gas from the vacuum chamber 101 in the subsequent plasma irradiation process, the vacuum chamber 101 was cleaned using plasma. In other words, the impurity gas is discharged in advance from the inner wall of the vacuum chamber 101, thereby preventing unintended gas from being mixed into the plasma in the subsequent plasma irradiation step. First, 30 sccm of H 2 was introduced into the vacuum chamber 101 using the mass flow controller 107, and the pressure in the vacuum chamber 101 was adjusted to 10 Pa.
　つぎに、プラズマが直接当たらないように、セットした基材１１５の上部をシャッター１１２で覆った状態で、真空チャンバー１０１内に高周波電力を供給してＨ２プラズマを２分間生成して、真空チャンバー１０１内をクリーニングした。クリーニング中のプラズマの質量分析から、プラズマ生成直後はＣＨ４とＨ２Ｏの存在が確認されたが、その後徐々に、ＣＨ４とＨ２Ｏの分圧が減少していく様子が観察された。クリーニング終了後、Ｈ２ガスの供給を止めて、真空チャンバー１０１内の圧力が１０－５Ｐａ台になるまで減圧した。 Next, high frequency power is supplied into the vacuum chamber 101 in a state where the upper portion of the set base material 115 is covered with the shutter 112 so that the plasma does not directly hit, and the H 2 plasma is generated for 2 minutes. 101 was cleaned. From the mass analysis of the plasma during cleaning, the presence of CH 4 and H 2 O was confirmed immediately after the generation of the plasma, but after that, it was observed that the partial pressure of CH 4 and H 2 O gradually decreased. . After the cleaning was completed, the supply of H 2 gas was stopped, and the pressure was reduced until the pressure in the vacuum chamber 101 reached the 10 −5 Pa level.
（２）基材加熱工程
　真空チャンバー１０１内の圧力が１０－５Ｐａ台まで下がった後、Ｈ２ガス３０ｓｃｃｍを真空チャンバー１０１内に供給し、圧力を１０Ｐａに維持しながら、基材１１５に直流電力を供給して１０分間加熱した。銅箔に電圧を印加することで発生するジュール熱を利用して、基材１１５を加熱（ジュール加熱）した。ジュール加熱は、低消費電力、急速加熱、および加熱によるアウトガスの低減の点で優れている。加熱した基材１１５の温度は、銅箔抵抗の温度依存性から換算することで推測でき、本実施例では約９００℃であった。 (2) Substrate heating step After the pressure in the vacuum chamber 101 drops to the 10 −5 Pa level, 30 sccm of H 2 gas is supplied into the vacuum chamber 101, and DC is applied to the substrate 115 while maintaining the pressure at 10 Pa. Power was applied and heated for 10 minutes. The base material 115 was heated (Joule heating) using Joule heat generated by applying a voltage to the copper foil. Joule heating is excellent in terms of low power consumption, rapid heating, and reduction of outgas by heating. The temperature of the heated base material 115 can be estimated by converting from the temperature dependence of the copper foil resistance, and was about 900 ° C. in this example.
（３）プラズマ照射工程
　基材１１５の加熱終了後、基材１１５にプラズマを照射して窒素ドープグラフェン膜を生成させた。真空チャンバー１０１内に供給するＨ２ガスとＣＨ４ガスの流量をそれぞれ３０ｓｃｃｍと０.１２ｓｃｃｍに固定し、Ｎ２ガスの流量を０ｓｃｃｍ、０.２ｓｃｃｍ、０.４ｓｃｃｍの３通りに変化させた。真空チャンバー１０１内の圧力を１０Ｐａと、基材１１５の温度を６００～７５０℃と、基材１１５へのプラズマ照射時間を３分間とした。 (3) Plasma irradiation process After the heating of the base material 115, the base material 115 was irradiated with plasma to generate a nitrogen-doped graphene film. The flow rates of H 2 gas and CH 4 gas supplied into the vacuum chamber 101 were fixed at 30 sccm and 0.12 sccm, respectively, and the flow rate of N 2 gas was changed in three ways: 0 sccm, 0.2 sccm, and 0.4 sccm. The pressure in the vacuum chamber 101 was 10 Pa, the temperature of the substrate 115 was 600 to 750 ° C., and the plasma irradiation time to the substrate 115 was 3 minutes.
　基材１１５へのプラズマ照射終了後、後述するラマン分光測定によって窒素ドープグラフェン膜が生成していることを確認した。基材１１５は、縦１６ｍｍ、横１６ｍｍの正方形であった。基材１１５の全面に生成した本実施例の窒素ドープグラフェン膜の面積は、報告されている窒素ドープグラフェン膜の面積の同程度以上の大きさであった。 After the plasma irradiation to the base material 115, it was confirmed that a nitrogen-doped graphene film was formed by Raman spectroscopy measurement described later. The base material 115 was a square having a length of 16 mm and a width of 16 mm. The area of the nitrogen-doped graphene film of this example formed on the entire surface of the substrate 115 was equal to or larger than the reported area of the nitrogen-doped graphene film.
　図２はプラズマ照射工程での質量分析結果で、図２（ａ）はＮ２ガス流量が０ｓｃｃｍのときを、図２（ｂ）はＮ２ガス流量が０.２ｓｃｃｍのときをそれぞれ示している。なお、ＣＨ４ガスは、プラズマ生成の２０秒前に導入を開始し、プラズマ消失から２０秒後に導入を停止した。また、Ｎ２ガスの導入は、プラズマを生成した３分間のうち、最後の１分間のみとした。 FIG. 2 shows the results of mass spectrometry in the plasma irradiation process. FIG. 2A shows the case where the N 2 gas flow rate is 0 sccm, and FIG. 2B shows the case where the N 2 gas flow rate is 0.2 sccm. . The introduction of CH 4 gas was started 20 seconds before the plasma generation, and the introduction was stopped 20 seconds after the plasma disappeared. Further, the introduction of N 2 gas was performed only for the last one minute among the three minutes during which plasma was generated.
　図２（ａ）に示すように、真空チャンバー１０１内にＮ２ガスを導入しなくても、プラズマ中にＮ２が含まれていた。このプラズマ中のＮ２は、基材加熱工程後に真空チャンバー１０１内に存在していた不可避不純物のＮ２ガスによるものと考えられる。このため、真空チャンバー１０１内にＮ２ガスを導入しなくても、窒素ドープグラフェン膜が得られた。また、Ｎ２ガスを導入することで、図２（ｂ）に示すように、Ｎ２分圧が増加している様子が確認できた。 As shown in FIG. 2A, N 2 was contained in the plasma without introducing N 2 gas into the vacuum chamber 101. N 2 in this plasma is considered to be due to N 2 gas of inevitable impurities present in the vacuum chamber 101 after the substrate heating step. Therefore, a nitrogen-doped graphene film was obtained without introducing N 2 gas into the vacuum chamber 101. Further, it was confirmed that the N 2 partial pressure was increased by introducing N 2 gas as shown in FIG.
　プラズマ生成中、プラズマの全圧（ほぼ水素の分圧に相当する）は９.９～１０.１Ｐａで、Ｈ２Ｏの分圧は５.３×１０－３～８.４×１０－３Ｐａで、Ｏ２の分圧は１.４×１０－３～１.６×１０－３Ｐａで、ＣＨ４の分圧は２.８×１０－２～４.６×１０－２Ｐａで、Ｎ２の分圧は１.９×１０－２～２.７×１０－２Ｐａであった。プラズマ生成中の各時刻で、Ｈ２Ｏの分圧はプラズマの全圧の０.０１５以下で、Ｏ２の分圧はプラズマの全圧の０.００２以下であった。また、プラズマ生成中の各時刻で、Ｈ２Ｏの分圧はＣＨ４の分圧の０.３５以下であった。また、プラズマ生成中の各時刻で、Ｎ２の分圧はＣＨ４の分圧の０.３８～０.６８であった。なお、図２（ａ）の条件では、プラズマ生成中の各時刻で、Ｎ２の分圧はＣＨ４の分圧の０.５８～０.６８であった。 During plasma generation, the total plasma pressure (approximately equivalent to the partial pressure of hydrogen) is 9.9 to 10.1 Pa, and the partial pressure of H 2 O is 5.3 × 10 −3 to 8.4 × 10 −3. Pa, the partial pressure of O 2 is 1.4 × 10 −3 to 1.6 × 10 −3 Pa, and the partial pressure of CH 4 is 2.8 × 10 −2 to 4.6 × 10 −2 Pa. The partial pressure of N 2 was 1.9 × 10 −2 to 2.7 × 10 −2 Pa. At each time during plasma generation, the partial pressure of H 2 O was 0.015 or less of the total plasma pressure, and the partial pressure of O 2 was 0.002 or less of the total plasma pressure. At each time during plasma generation, the partial pressure of H 2 O was 0.35 or less of the partial pressure of CH 4 . Further, at each time during plasma generation, the partial pressure of N 2 was 0.38 to 0.68 of the partial pressure of CH 4 . 2A, the partial pressure of N 2 was 0.58 to 0.68 of the partial pressure of CH 4 at each time during plasma generation.
２.窒素ドープグラフェン膜のＳｉ基板への転写
　以下のようにして、プラズマ照射工程で得られた窒素ドープグラフェン膜を、表面に厚さ１００ｎｍのＳｉＯ２膜が形成されたＳｉ基板（以下、Ｓｉの表面にＳｉＯ２が形成された基板を「ＳｉＯ２／Ｓｉ基板」と記載することがある。他の積層体についても同様である）に転写した。まず、ポリメタクリル酸メチル樹脂（ＰＭＭＡ）の２質量％アニソール溶液を、窒素ドープグラフェン膜／銅箔の表面に３０００ｒｐｍで３０秒間スピンコートした。ＰＭＭＡ／窒素ドープグラフェン膜／銅箔を自然乾燥させた後、０.５ｍｏｌ／Ｌ過硫酸アンモニウムを用いて銅箔をエッチング除去して、ＰＭＭＡ／窒素ドープグラフェン膜を得た。 2. Transfer of Nitrogen-Doped Graphene Film to Si Substrate As described below, the nitrogen-doped graphene film obtained in the plasma irradiation step was used as a Si substrate (hereinafter referred to as Si substrate) having a 100 nm thick SiO 2 film formed on the surface. The substrate having SiO 2 formed on the surface thereof is sometimes referred to as “SiO 2 / Si substrate. The same applies to other laminated bodies”. First, a 2% by mass anisole solution of polymethyl methacrylate resin (PMMA) was spin-coated at 3000 rpm for 30 seconds on the surface of a nitrogen-doped graphene film / copper foil. After the PMMA / nitrogen-doped graphene film / copper foil was naturally dried, the copper foil was removed by etching using 0.5 mol / L ammonium persulfate to obtain a PMMA / nitrogen-doped graphene film.
　つぎに、窒素ドープグラフェン膜とＳｉＯ２膜が接するように、ＰＭＭＡ／窒素ドープグラフェン膜をＳｉＯ２／Ｓｉ基板に重ね合わせた。そして、アセトンに浸潤してＰＭＭＡを除去した。その後、石英チューブ炉内にアルゴンと水素を１０ｓｃｃｍずつ導入しながら、温度４００℃、圧力１００Ｐａで２時間アニールを行って、窒素ドープグラフェン膜／ＳｉＯ２／Ｓｉ基板を得た。 Next, the PMMA / nitrogen-doped graphene film was superposed on the SiO 2 / Si substrate so that the nitrogen-doped graphene film and the SiO 2 film were in contact with each other. And it infiltrated with acetone and removed PMMA. Thereafter, annealing was performed at 400 ° C. and a pressure of 100 Pa for 2 hours while introducing 10 sccm of argon and hydrogen into the quartz tube furnace to obtain a nitrogen-doped graphene film / SiO 2 / Si substrate.
３.窒素ドープグラフェン膜のラマン分光測定
　窒素ドープグラフェン膜の結晶品質を評価するため、ラマン分光装置（堀場製作所、Ｘｐｌｏｒａ）を用いて、波長５３２ｎｍのレーザー光で窒素ドープグラフェン膜のラマン分光を測定した。得られたラマンスペクトルを図３に示す。図３（ａ）は、プラズマ照射工程でＮ２ガスを真空チャンバー１０１内に導入せずに作製した窒素ドープグラフェン膜のラマンスペクトルである。図３（ｂ）は、プラズマ照射工程でＮ２ガスを真空チャンバー１０１内に０.２ｓｃｃｍ導入して作製した窒素ドープグラフェン膜のラマンスペクトルである。図３（ｃ）は、プラズマ照射工程でＮ２ガスを真空チャンバー１０１内に０.４ｓｃｃｍ導入して作製した窒素ドープグラフェン膜のラマンスペクトルである。 3. Raman spectroscopy measurement of nitrogen-doped graphene film In order to evaluate the crystal quality of nitrogen-doped graphene film, Raman spectroscopy of nitrogen-doped graphene film was measured with a laser beam with a wavelength of 532 nm using a Raman spectrometer (Horiba, Xplora) did. The obtained Raman spectrum is shown in FIG. FIG. 3A is a Raman spectrum of a nitrogen-doped graphene film manufactured without introducing N 2 gas into the vacuum chamber 101 in the plasma irradiation process. FIG. 3B is a Raman spectrum of a nitrogen-doped graphene film manufactured by introducing N 2 gas into the vacuum chamber 101 by 0.2 sccm in the plasma irradiation process. FIG. 3C is a Raman spectrum of a nitrogen-doped graphene film produced by introducing 0.4 sccm of N 2 gas into the vacuum chamber 101 in the plasma irradiation process.
　図３（ａ）から図３（ｃ）の全てのラマンスペクトルで、Ｇバンドと２Ｄバンドが観察された。また、欠陥を示すＤバンドに関しては、Ｎ２ガス導入量の増大に伴って、Ｇバンドおよび２Ｄバンドとの相対的な強度が増大した。Ｎ２ガス導入量を増加させることで、グラフェンドメインのエッジに窒素原子が付き始めたか、またはグラフェンのエッチングが始まりグラフェンのドメインサイズが減少している可能性が考えられる。 G band and 2D band were observed in all Raman spectra of FIG. 3A to FIG. In addition, regarding the D band indicating defects, the relative strength with the G band and the 2D band increased with an increase in the amount of N 2 gas introduced. By increasing the amount of N 2 gas introduced, there is a possibility that nitrogen atoms have started to be attached to the edge of the graphene domain, or etching of graphene has started and the domain size of graphene has decreased.
　ラマンスペクトルから得られるＧバンド強度に対するＤバンド強度の比（ＩＤ／ＩＧ）から、グラフェンのドメインサイズＬａを見積もることができる。すなわち、Ｌａ〔ｎｍ〕＝（２.４×１０－１０）λ４（ＩＤ／ＩＧ）－１の計算式で与えられる。例えば、図３（ａ）の結果から得られるグラフェンのドメインサイズＬａは約３８～約５３ｎｍと見積もられる。また、図３（ｂ）では、グラフェンのドメインサイズＬａが約３７～約５３ｎｍと見積もられる。なお、後述するように、図３（ａ）の窒素ドープグラフェン膜は、主にピリジン型の窒素ドープグラフェン膜であると推測される。このように、グラフェンのドメインサイズが３７～５３ｎｍであるピリジン型の窒素ドープグラフェン膜が得られた。 From the ratio of D band intensity to the G-band intensity obtained from the Raman spectra (I D / I G), it is possible to estimate the domain size L a graphene. That is, L a [nm] = (2.4 × 10 −10 ) λ 4 (I D / I G ) −1 is given by the calculation formula. For example, the graphene domain size La obtained from the result of FIG. 3A is estimated to be about 38 to about 53 nm. Further, in FIG. 3 (b), the domain size L a of the graphene is estimated to be about 37 to about 53 nm. As will be described later, the nitrogen-doped graphene film in FIG. 3A is presumed to be mainly a pyridine type nitrogen-doped graphene film. Thus, a pyridine-type nitrogen-doped graphene film having a graphene domain size of 37 to 53 nm was obtained.
４.窒素ドープグラフェン膜のデバイス作製
　Ｓｉ基板に転写した窒素ドープグラフェン膜の電気伝導特性を測定するため、以下のようにしてデバイス作製を行った。なお、各工程は、特許文献１に記載された方法とほぼ同じである。まず、コンタクトマスクアライナ（ＳＵＳＳ　ＭｉｃｒｏＴｅｃ社、ＭＪＢ４）を用いたフォトリソグラフィ技術によって、波長４３６ｎｍ、照度約４０ｍＷ／ｃｍ２、露光時間２秒間で、フォトマスク（株式会社進映社製のクロムマスク）を用いて、窒素ドープグラフェン膜のパターニングを行った。露光後、現像とベーキングを行って、窒素ドープグラフェン膜／ＳｉＯ２／Ｓｉ基板上に、所定のパターンのフォトレジストを形成して試料を得た。 4. Device Fabrication of Nitrogen-Doped Graphene Film A device was fabricated as follows in order to measure the electrical conductivity characteristics of the nitrogen-doped graphene film transferred to the Si substrate. Each process is substantially the same as the method described in Patent Document 1. First, a photomask (chrome mask manufactured by Shineisha Co., Ltd.) is used with a photolithographic technique using a contact mask aligner (SUSS MicroTec, MJB4) at a wavelength of 436 nm, an illuminance of about 40 mW / cm 2 and an exposure time of 2 seconds Then, the nitrogen-doped graphene film was patterned. After exposure, development and baking were performed to form a photoresist with a predetermined pattern on a nitrogen-doped graphene film / SiO 2 / Si substrate to obtain a sample.
　つぎに、プラズマアッシャ（株式会社ヤマト科学、ＰＲ５００）を用いて、この試料上の余分な窒素ドープグラフェン膜を除去した。すなわち、このプラズマアッシャの石英チャンバー内圧力を１００Ｐａにし、Ｏ２ガスを１３０ｓｃｃｍ導入しながら、出力２００Ｗで５分間プラズマを発生させた。その後、試料にアセトンを浸潤させてレジストを除去し、ＳｉＯ２／Ｓｉ基板上に所定のパターンで存在する窒素ドープグラフェン膜を得た。 Next, using a plasma asher (Yamato Scientific Co., Ltd., PR500), the excess nitrogen-doped graphene film on this sample was removed. That is, the pressure in the quartz chamber of the plasma asher was set to 100 Pa, and plasma was generated at an output of 200 W for 5 minutes while introducing O 2 gas at 130 sccm. Thereafter, acetone was infiltrated into the sample to remove the resist, and a nitrogen-doped graphene film existing in a predetermined pattern on the SiO 2 / Si substrate was obtained.
　そして、この窒素ドープグラフェン膜上に、フォトリソグラフィ技術と、真空蒸着装置（株式会社エイコー・エンジニアリング製）を用いた金属蒸着によって、金／ニッケルから構成されるコンタクト電極を所定のパターンで形成した。蒸着した金属の膜厚は、水晶振動子膜厚モニタにより制御した。つぎに、アセトンを用いて試料のフォトレジストを除去した。その後、石英チューブ炉にＡｒガス９５ｓｃｃｍとＨ２ガス５ｓｃｃｍを導入しながら、圧力１００Ｐａ、温度３００℃で、３時間アニールして、デバイス表面のレジスト残渣を除去してデバイス試料を得た。 Then, a contact electrode composed of gold / nickel was formed in a predetermined pattern on the nitrogen-doped graphene film by metal deposition using a photolithography technique and a vacuum deposition apparatus (manufactured by Eiko Engineering Co., Ltd.). The thickness of the deposited metal was controlled by a crystal oscillator thickness monitor. Next, the photoresist of the sample was removed using acetone. Thereafter, while introducing Ar gas 95 sccm and H 2 gas 5 sccm into the quartz tube furnace, annealing was performed at a pressure of 100 Pa and a temperature of 300 ° C. for 3 hours to remove a resist residue on the device surface, thereby obtaining a device sample.
５.窒素ドープグラフェン膜の電気伝導特性評価
　低温真空プローバー（株式会社システムブレイン、Ｍｏｄｅｌ：ＳＢ－ＭＣＰＳ）を用いて、デバイス試料の電気伝導特性を評価した。すなわちまず、圧力１０－２Ｐａ台、温度２００℃で、デバイス試料を６時間加熱し、グラフェン表面から酸素および水を放出させた。つぎに、半導体試験システム（Ｋｅｉｔｈｌｅｙ、４２００－ＳＣＳ）を用いて、ホールバー素子を用いた４端子測定によって、デバイス試料の電気伝導特性を測定した。両端の２つの電極に固定電圧（ドレイン電圧：ＶＤＳ）を印加し、中央の２つの端子から電圧値（Ｖ）をモニタする。この電圧値から窒素ドープグラフェン膜の導電率（Ｓ）が算出される。ＶＤＳを印加しながら背面電圧（ゲート電圧：ＶＧＳ）を－１５Ｖから１５Ｖに掃引することで導電率（Ｓ）－ＶＧＳ（Ｖ）特性が得られる。 5. Evaluation of electric conductivity of nitrogen-doped graphene film Using a low-temperature vacuum prober (System Brain, Model: SB-MCPS), the electric conductivity of the device sample was evaluated. That is, first, the device sample was heated for 6 hours at a pressure of about 10 −2 Pa and a temperature of 200 ° C. to release oxygen and water from the graphene surface. Next, using a semiconductor test system (Keithley, 4200-SCS), the electrical conductivity characteristics of the device sample were measured by 4-terminal measurement using a Hall bar element. A fixed voltage (drain voltage: V DS ) is applied to the two electrodes at both ends, and the voltage value (V) is monitored from the two central terminals. From this voltage value, the conductivity (S) of the nitrogen-doped graphene film is calculated. The conductivity (S) -V GS (V) characteristic is obtained by sweeping the back surface voltage (gate voltage: V GS ) from −15 V to 15 V while applying V DS .
　プラズマ照射工程でＮ２ガスを真空チャンバー１０１内に導入せずに作製した窒素ドープグラフェン膜の電気伝導特性を図４（ａ）に示す。理想的なグラフェン膜であれば、グラフの傾き（相互コンダクタンス）の絶対値は、電子（ディラックポイントよりも右側）部分とホール（ディラックポイントよりも左側）部分で一致する。しかし、本実施例の窒素ドープグラフェン膜では、電子側の傾きの絶対値がホール側の傾きの絶対値より大きくなった。これは、本実施例の窒素ドープグラフェン膜の電子電界効果移動度がホール電界効果移動度よりも高いことを意味している。 FIG. 4A shows the electric conduction characteristics of a nitrogen-doped graphene film manufactured without introducing N 2 gas into the vacuum chamber 101 in the plasma irradiation step. In the case of an ideal graphene film, the absolute value of the slope (transconductance) of the graph is the same in the electron (on the right side of the Dirac point) portion and the hole (on the left side of the Dirac point) portion. However, in the nitrogen-doped graphene film of this example, the absolute value of the inclination on the electron side was larger than the absolute value of the inclination on the hole side. This means that the electron field effect mobility of the nitrogen-doped graphene film of this example is higher than the hole field effect mobility.
　図４（ｂ）は、プラズマ照射工程でＮ２ガスを真空チャンバー１０１内に０.２ｓｃｃｍ導入したときの電気伝導特性を示す。図４（ｃ）は、プラズマ照射工程でＮ２ガスを真空チャンバー１０１内に０.４ｓｃｃｍ導入したときの電気伝導特性を示す。Ｎ２ガス導入量の増加に伴って、電子側の傾きの絶対値とホール側の傾きの絶対値が同程度になっていく様子が観察された。 FIG. 4B shows the electric conduction characteristics when N 2 gas is introduced into the vacuum chamber 101 by 0.2 sccm in the plasma irradiation step. FIG. 4C shows electrical conduction characteristics when N 2 gas is introduced into the vacuum chamber 101 at 0.4 sccm in the plasma irradiation step. It was observed that the absolute value of the inclination on the electron side and the absolute value of the inclination on the hole side became approximately the same as the amount of N 2 gas introduced was increased.
　複数のデバイス試料について測定したホール電界効果移動度に対する電子電界効果移動度の比を図５に示す。電子電界効果移動度およびホール電界移動度は、下記の式により算出した。
　μＦＥ＝１／ｅｎρ、ｎ＝Ｃｏｘ（ＶＧ－ＶＤｉｒａｃ）
　ここで、μＦＥは電界効果移動度、ｅは電荷量、ｎはキャリア密度、ρは抵抗率、Ｃｏｘは酸化膜容量、ＶＧはゲート電圧、ＶＤｉｒａｃはディラック点の電圧値である。なお、電界効果移動度を算出する際のキャリア密度は、固定値２×１０１２ｃｍ－２を用いた。図５に示すように、プラズマ照射工程で真空チャンバー１０１内に導入するＮ２ガス流量の増加に伴って、電子電界効果移動度とホール電界効果移動度の比率が１に近づいている。 FIG. 5 shows the ratio of the electron field effect mobility to the Hall field effect mobility measured for a plurality of device samples. The electron field effect mobility and the Hall field mobility were calculated by the following equations.
μ FE = 1 / enρ, n = C ox (V G -V Dirac)
Here, mu FE field-effect mobility, e is the charge amount, n represents carrier density, [rho is resistivity, Cox is oxide capacitance, V G is the gate voltage, V Dirac is the voltage value of the Dirac point. Note that a fixed value of 2 × 10 12 cm −2 was used as the carrier density when calculating the field effect mobility. As shown in FIG. 5, the ratio of the electron field effect mobility and the hole field effect mobility approaches 1 as the flow rate of N 2 gas introduced into the vacuum chamber 101 in the plasma irradiation process increases.
　なお、図５の参照試料（Ｒｅｆ.）は、熱ＣＶＤ法で合成したグラフェン（グラフェンプラットフォーム社製）についての測定結果である。デバイス作製や電気特性評価方法は本実施例と同一である。本実施例では、同一キャリア密度におけるホール電界効果移動度に対する電子電界効果移動度の比が１.１５以上である窒素ドープグラフェン膜が得られた（Ｎ２：０ｓｃｃｍと０.２ｓｃｃｍ）。 In addition, the reference sample (Ref.) Of FIG. 5 is a measurement result about the graphene (made by a graphene platform company) synthesize | combined with the thermal CVD method. Device fabrication and electrical property evaluation methods are the same as in this example. In this example, a nitrogen-doped graphene film having a ratio of the electron field effect mobility to the hole field effect mobility at the same carrier density of 1.15 or more was obtained (N 2 : 0 sccm and 0.2 sccm).
６.窒素ドープグラフェン膜の構造解析
　グラフェンの炭素原子が窒素原子とどのように置換されているかを推測するため、元素分析が可能なＸ線光電子分光分析装置（ＵＬＶＡＣ－ＰＨＩ社製）を用いて、プラズマ照射工程でＮ２ガスを真空チャンバー１０１内に導入せずに銅箔上に作製した窒素ドープグラフェン膜（試料Ａ）と、Ｎ２ガスを０.４ｓｃｃｍ導入したときの銅箔上の窒素ドープグラフェン膜（試料Ｂ）のＸＰＳ測定を行った。測定結果（Ｎ　１ｓ）を図６に示す。図６（ａ）が試料ＡのＸＰＳスペクトルを、図６（ｂ）が試料ＢのＸＰＳスペクトルを示している。 6. Structural analysis of nitrogen-doped graphene film To estimate how carbon atoms of graphene are replaced with nitrogen atoms, an X-ray photoelectron spectrometer (ULVAC-PHI) capable of elemental analysis is used. The nitrogen-doped graphene film (sample A) produced on the copper foil without introducing the N 2 gas into the vacuum chamber 101 in the plasma irradiation step, and the nitrogen on the copper foil when the N 2 gas is introduced at 0.4 sccm XPS measurement of the doped graphene film (Sample B) was performed. The measurement results (N 1s) are shown in FIG. 6A shows the XPS spectrum of Sample A, and FIG. 6B shows the XPS spectrum of Sample B.
　図６（ａ）のＸＰＳスペクトルでは、３９８ｅＶ近傍にメインピークが、４００ｅＶ近傍にサテライトピークが観察された。試料Ａでは、ピリジン型での窒素置換が優先的に起こっていると推測される。一方、図６（ｂ）のＸＰＳスペクトルでは、４００ｅＶ近傍にメインピークが観察された。試料Ｂでは、Ｐｒｙｒｏｎｉｃ型での窒素置換が実現したことを示唆している。これらの結果は、窒素流量を変化させる、または窒素を導入するタイミングを変化させることで、グラフェンの炭素原子を窒素原子で置換する位置が制御できる可能性を示している。 In the XPS spectrum of FIG. 6A, a main peak was observed in the vicinity of 398 eV, and a satellite peak was observed in the vicinity of 400 eV. In sample A, it is presumed that nitrogen substitution in the pyridine type occurs preferentially. On the other hand, in the XPS spectrum of FIG. 6B, a main peak was observed in the vicinity of 400 eV. Sample B suggests that the substitution of nitrogen in the Pronic type has been realized. These results indicate the possibility that the position of replacing the carbon atom of graphene with the nitrogen atom can be controlled by changing the flow rate of nitrogen or changing the timing of introducing nitrogen.
７.窒素ドープグラフェン膜の電気伝導特性評価２
　ここでは、真空チャンバークリーニング工程を行わず、基材加熱工程およびプラズマ照射工程の二工程を経てグラフェンを作製した。なお、処理条件と評価方法は上記と同一である。図７（a）は、プラズマ照射工程でＮ２ガスを導入せずに作製した窒素ドープグラフェン膜の電気伝導特性を×印で示している。図７（ｂ）は、Ｎ２ガスを０．２ｓｃｃｍ導入して作製した窒素ドープグラフェン膜の電気伝導特性を×印で示している。 7. Electrical conductivity characteristics evaluation of nitrogen-doped graphene film 2
Here, the vacuum chamber cleaning process was not performed, and the graphene was manufactured through two processes of a base material heating process and a plasma irradiation process. The processing conditions and the evaluation method are the same as described above. FIG. 7A shows the electric conduction characteristics of a nitrogen-doped graphene film manufactured without introducing N 2 gas in the plasma irradiation step by x marks. FIG. 7B shows the electric conduction characteristics of a nitrogen-doped graphene film produced by introducing 0.2 sccm of N 2 gas with x marks.
　なお、真空チャンバークリーニング工程がある場合を●印で示した。どちらの場合でも、真空チャンバークリーニング工程があるときは、真空チャンバークリーニング工程がないときと比較して、グラフの非対称性が大きくなっている。すなわち、電気伝導特性のグラフの傾きがホール側と比較して電子側が急峻になっている様子が確認できる。以上の結果から、真空チャンバークリーニング工程を行うことが、窒素ドープグラフェン形成に大きな影響を与えていると推測される。 The case where there is a vacuum chamber cleaning process is indicated by ●. In either case, the asymmetry of the graph is greater when there is a vacuum chamber cleaning process than when there is no vacuum chamber cleaning process. That is, it can be confirmed that the slope of the graph of the electric conduction characteristic is steeper on the electron side than on the hole side. From the above results, it is estimated that the vacuum chamber cleaning process has a great influence on the formation of nitrogen-doped graphene.
１００　プラズマＣＶＤ装置
１０１　真空チャンバー
１０２　プラズマ発生装置
１０３　ターボ分子ポンプ
１０４　Ｈ２ボンベ
１０５　Ｎ２ボンベ
１０６　ＣＨ４ボンベ
１０７，１０８　マスフローコントローラ
１０９　微量マスフローコントローラ
１１０，１１１　ガス精製フィルタ
１１２　シャッター
１１３　試料ステージ
１１４　試料加熱ホルダー
１１５　基材
１１６　直流電源
１１８　質量分析装置
１１９　オリフィス管
１２０　ターボ分子ポンプ
１２１　スクリューポンプ DESCRIPTION OF SYMBOLS 100 Plasma CVD apparatus 101 Vacuum chamber 102 Plasma generator 103 Turbo molecular pump 104 H 2 cylinder 105 N 2 cylinder 106 CH 4 cylinder 107,108 Mass flow controller 109 Trace mass flow controller 110, 111 Gas purification filter 112 Shutter 113 Sample stage 114 Sample heating Holder 115 Base material 116 DC power supply 118 Mass spectrometer 119 Orifice tube 120 Turbo molecular pump 121 Screw pump

Claims (10)

  1. 　炭化水素およびＮ２を含有するプラズマを基材に照射して、前記基材上に窒素ドープグラフェン膜を生成させる窒素ドープグラフェン膜の製造方法であって、
    　前記プラズマ中に含まれることがあるＨ２Ｏの分圧が、前記プラズマの全圧の０.０１５以下で、
    　前記プラズマ中に含まれることがあるＯ２の分圧が、前記プラズマの全圧の０.００２以下である窒素ドープグラフェン膜の製造方法。     A method for producing a nitrogen-doped graphene film in which a substrate containing a hydrocarbon and N 2 is irradiated to generate a nitrogen-doped graphene film on the substrate,
    The partial pressure of H 2 O that may be contained in the plasma is 0.015 or less of the total pressure of the plasma,
    A method for producing a nitrogen-doped graphene film, wherein a partial pressure of O 2 that may be contained in the plasma is 0.002 or less of a total pressure of the plasma.
  2. 　請求項１において、
    　前記炭化水素がＣＨ４であり、
    　前記Ｈ２Ｏの分圧が、前記プラズマ中のＣＨ４の分圧の０.３５以下である窒素ドープグラフェン膜の製造方法。     In claim 1,
    The hydrocarbon is CH 4 ;
    A method for producing a nitrogen-doped graphene film, wherein the partial pressure of H 2 O is 0.35 or less of the partial pressure of CH 4 in the plasma.
  3. 　請求項２において、
    　前記プラズマ中のＮ２の分圧が、前記プラズマ中のＣＨ４の分圧の０.３８～０.６８である窒素ドープグラフェン膜の製造方法。     In claim 2,
    A method for producing a nitrogen-doped graphene film, wherein a partial pressure of N 2 in the plasma is 0.38 to 0.68 of a partial pressure of CH 4 in the plasma.
  4. 　請求項３において、
    　前記プラズマ中のＮ２の分圧が、前記プラズマ中のＣＨ４の分圧の０.５８～０.６８である窒素ドープグラフェン膜の製造方法。     In claim 3,
    A method for producing a nitrogen-doped graphene film, wherein a partial pressure of N 2 in the plasma is 0.58 to 0.68 of a partial pressure of CH 4 in the plasma.
  5. 　請求項１から４のいずれかにおいて、
    　前記基材の温度を６００～７５０℃に維持しながら前記基材上に窒素ドープグラフェンを生成させる窒素ドープグラフェン膜の製造方法。     In any one of Claim 1-4,
    A method for producing a nitrogen-doped graphene film, wherein nitrogen-doped graphene is produced on the substrate while maintaining the temperature of the substrate at 600 to 750 ° C.
  6. 　銅を主成分とする基材を真空チャンバーに入れ、Ｈ２プラズマで前記真空チャンバー内をクリーニングするクリーニング工程と、
    　前記真空チャンバーにＨ２ガスを導入しながら、前記基材に直流電力を供給して前記基材を加熱する加熱工程と、
    　前記真空チャンバーにＨ２ガスおよびＣＨ４ガスを含む原料ガスを導入し、前記原料ガスをプラズマ化して、前記基材上に窒素ドープグラフェン膜を生成させる生成工程と、
    　を有する窒素ドープグラフェン膜の製造方法。     A cleaning step of putting a base material mainly composed of copper in a vacuum chamber and cleaning the inside of the vacuum chamber with H 2 plasma;
    A heating step of heating the substrate by supplying DC power to the substrate while introducing H 2 gas into the vacuum chamber;
    Introducing a source gas containing H 2 gas and CH 4 gas into the vacuum chamber, converting the source gas into plasma, and generating a nitrogen-doped graphene film on the substrate;
    A method for producing a nitrogen-doped graphene film having:
  7. 　請求項６において、
    　前記生成工程では、前記真空チャンバーにＮ２ガスを途中から導入する窒素ドープグラフェン膜の製造方法。     In claim 6,
    In the producing step, a method for producing a nitrogen-doped graphene film, wherein N 2 gas is introduced into the vacuum chamber from the middle.
  8. 　グラフェン骨格の一部の炭素原子が窒素原子で置換された窒素ドープグラフェン膜であって、
    　同一キャリア密度におけるホール電界効果移動度に対する電子電界効果移動度の比が１.１５以上である窒素ドープグラフェン膜。     A nitrogen-doped graphene film in which some carbon atoms of the graphene skeleton are replaced with nitrogen atoms,
    A nitrogen-doped graphene film in which the ratio of the electron field effect mobility to the hole field effect mobility at the same carrier density is 1.15 or more.
  9. 　グラフェン骨格の一部の炭素原子が窒素原子で置換された主にピリジン型の窒素ドープグラフェン膜であって、
    　グラフェンのドメインサイズが１０～２００ｎｍである窒素ドープグラフェン膜。     It is a nitrogen-doped graphene film mainly of pyridine type in which some carbon atoms of the graphene skeleton are substituted with nitrogen atoms,
    A nitrogen-doped graphene film having a graphene domain size of 10 to 200 nm.
  10. 　請求項９において、
    　前記グラフェンのドメインサイズが３７～５３ｎｍである窒素ドープグラフェン膜。     In claim 9,
    A nitrogen-doped graphene film, wherein the graphene has a domain size of 37 to 53 nm.
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Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
RU2717069C1 (en) * 2019-06-27 2020-03-17 Федеральное государственное бюджетное учреждение науки Объединенный институт высоких температур Российской академии наук (ОИВТ РАН) Method for direct synthesis of nitrated graphene plates
WO2020093426A1 (en) * 2018-11-06 2020-05-14 西安交通大学 Method for horizontally laying and self-assembling graphene to form graphene film
CN111487298A (en) * 2020-04-24 2020-08-04 深圳市溢鑫科技研发有限公司 SPE electrode taking vertical graphene as catalytic material and preparation method thereof
RU2750709C1 (en) * 2020-10-19 2021-07-01 Федеральное государственное бюджетное учреждение науки "Федеральный исследовательский центр "Институт катализа им. Г.К. Борескова Сибирского отделения Российской академии наук" (ИК СО РАН, Институт катализа СО РАН) Graphene modified by nitrogen atoms and its manufacturing method
CN113422082A (en) * 2021-07-06 2021-09-21 中国科学技术大学 Nitrogen-doped carbon five-membered ring structure-containing graphene-like carbon material electrocatalyst and preparation method and application thereof
WO2022255080A1 (en) * 2021-05-31 2022-12-08 東京エレクトロン株式会社 Film formation method and film formation apparatus

Families Citing this family (1)

* Cited by examiner, † Cited by third party
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CN114573099B (en) * 2022-03-02 2023-03-17 齐鲁工业大学 Method for promoting enrichment of anaerobic ammonium oxidation bacteria by nitrogen-doped graphene

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2013080565A (en) * 2011-09-30 2013-05-02 Toshiba Corp Conductive material and electric element using the same
JP2013173660A (en) * 2012-02-27 2013-09-05 Sekisui Nano Coat Technology Co Ltd Method for manufacturing graphene film doped with nitrogen atom
WO2014180919A1 (en) * 2013-05-08 2014-11-13 MAX-PLANCK-Gesellschaft zur Förderung der Wissenschaften e.V. Graphene with very high charge carrier mobility and preparation thereof

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2013080565A (en) * 2011-09-30 2013-05-02 Toshiba Corp Conductive material and electric element using the same
JP2013173660A (en) * 2012-02-27 2013-09-05 Sekisui Nano Coat Technology Co Ltd Method for manufacturing graphene film doped with nitrogen atom
WO2014180919A1 (en) * 2013-05-08 2014-11-13 MAX-PLANCK-Gesellschaft zur Förderung der Wissenschaften e.V. Graphene with very high charge carrier mobility and preparation thereof

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2020093426A1 (en) * 2018-11-06 2020-05-14 西安交通大学 Method for horizontally laying and self-assembling graphene to form graphene film
US11724940B2 (en) 2018-11-06 2023-08-15 Xi'an Jiaotong University Method for forming graphene film through horizontally tiling and self-assembling graphene
RU2717069C1 (en) * 2019-06-27 2020-03-17 Федеральное государственное бюджетное учреждение науки Объединенный институт высоких температур Российской академии наук (ОИВТ РАН) Method for direct synthesis of nitrated graphene plates
CN111487298A (en) * 2020-04-24 2020-08-04 深圳市溢鑫科技研发有限公司 SPE electrode taking vertical graphene as catalytic material and preparation method thereof
RU2750709C1 (en) * 2020-10-19 2021-07-01 Федеральное государственное бюджетное учреждение науки "Федеральный исследовательский центр "Институт катализа им. Г.К. Борескова Сибирского отделения Российской академии наук" (ИК СО РАН, Институт катализа СО РАН) Graphene modified by nitrogen atoms and its manufacturing method
WO2022255080A1 (en) * 2021-05-31 2022-12-08 東京エレクトロン株式会社 Film formation method and film formation apparatus
KR20240012487A (en) 2021-05-31 2024-01-29 도쿄엘렉트론가부시키가이샤 Film formation method and film formation equipment
CN113422082A (en) * 2021-07-06 2021-09-21 中国科学技术大学 Nitrogen-doped carbon five-membered ring structure-containing graphene-like carbon material electrocatalyst and preparation method and application thereof
CN113422082B (en) * 2021-07-06 2023-04-21 中国科学技术大学 Graphene-like carbon material electrocatalyst containing nitrogen-doped carbon five-membered ring structure, and preparation method and application thereof

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