JP2005060920A - Method for manufacturing ultrafine carbon fiber and field emission element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing an ultrafine carbon fiber capable of controlling diameter thereof, and to provide a method for manufacturing a field emission element in which an electron emission portion is formed of an ultrafine carbon fiber and which is possible to control the density and the diameter thereof. <P>SOLUTION: A size and density of a metal element or a silicide of the metal element is controlled and cohered in a crystal grain boundary of a semiconductor film, and an ultrafine carbon fiber is formed by using the metal element or the metal silicide as a core. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

    The present invention relates to a graphite nanofiber, a carbon nanofiber, a carbon nanotube, a tube-shaped graphite, a carbon nanocone with a thin tip, a very fine carbon fiber such as cone-shaped graphite, and a method for producing a field emission device having an ultrafine carbon fiber About.

  In recent years, ultrafine carbon fibers are expected to be applied to various devices. For this reason, various methods for producing ultrafine carbon fibers have been studied.

  Typical methods for producing ultrafine carbon fibers include an arc discharge method, a laser evaporation method, a CVD (Chemical vapor deposition) method, and the like (see Non-Patent Document 1).

  Representative examples of ultrafine carbon fibers include carbon nanotubes (hereinafter referred to as CNT (Carbon Nanotube)), carbon nanofibers, graphite nanofibers, tube-like graphite, carbon nanocones with sharp tips, cone-like graphite, etc. Examples include ultrafine carbon fibers and fullerenes.

  CNT refers to nanometer-sized cylindrical graphite. CNT includes single-wall nanotubes and multi-wall nanotubes. A single-walled nanotube is a tube in which a single graphene sheet (monoatomic carbon hexagonal network surface) is closed in a cylindrical shape, and has a diameter of about 1 to 10 nm and a length of 1 to 100 μm. Multi-walled nanotubes are obtained by stacking cylindrical graphene sheets in multiple layers, and have an outer diameter of 5 to 50 nm, a central cavity diameter of 3 to 10 nm, and a length of 1 to 100 μm.

CNT has a sharp tip and needle-like shape, is thermally and chemically stable, mechanically tough, and has electrical conductivity. (Scanning Probe Microscope; SPM), a field emission device of a field emission display (hereinafter referred to as FED (Field Emission Display)), and a channel region of an FET (Field Effect Transistor). In addition, research has been conducted on negative electrode materials, gas storage materials, and the like of lithium batteries by taking advantage of the structure of one-dimensional pores with essentially large spaces in and between tubes.

In addition, the ultrafine carbon fiber has a low work function and a negative electron affinity, so that it is applied as a field emission element of a field emission display device.

As an example of a manufacturing method using ultrafine carbon fiber for a field emission device of FED, as described in Patent Document 1, metal dots are formed on a partially exposed silicon substrate surface, and silicon is formed on the metal dots by an electromagnet. There is one in which a magnetic field is applied in a direction perpendicular to the substrate surface and CNTs are grown between the metal dots and the silicon substrate while attracting the metal dots to form an electron emission portion (see Patent Document 1).
"Carbon Nanotubes-Expected Material Development", CMC Corporation, November 10, 2001, p3-4 JP 2000-86216 A

  However, in the conventional manufacturing method, it is difficult to control the diameter and length of the ultrafine carbon fiber independently, and there is a problem that the variation in diameter is large. In general, when forming ultrafine carbon fibers such as CNTs using a metal film as a catalyst, it is said that these diameters depend on the diameter of the metal film. In Patent Literature 1, CNTs are formed using metal dots as a catalyst, but the process of forming metal dots of several nm to several tens of nm is complicated, that is, it is difficult to control the diameter of CNTs. There was a problem.

  The present invention has been made in view of the above problems, and an object thereof is to provide a method for producing an ultrafine carbon fiber capable of controlling the diameter. Another object of the present invention is to propose a method for manufacturing a field emission device in which the electron emission portion is formed of ultrafine carbon fibers and the density and diameter thereof can be controlled.

  The present invention is characterized by controlling the size and density of a metal element or metal silicide at the grain boundary of a semiconductor film and agglomerating to form ultrafine carbon fibers with the metal element or metal silicide as a nucleus. .

  In addition, the present invention controls the density of multiple points of crystal grains of a semiconductor film formed on an insulating surface, and contains carbon after aggregating a metal element or a metal silicide on the surface of the multiple points. Heat treatment or plasma treatment is performed in an atmosphere to form ultrafine carbon fibers, and the ultrafine carbon fibers are dissociated from the crystalline semiconductor film.

  In addition, the present invention controls the size and density of a metal element or metal silicide at the crystal grain boundary of a semiconductor film to cause aggregation, and uses the metal element or metal silicide as a nucleus to form ultrafine carbon fibers as an electron emission portion. A field emission device is formed.

 In addition, the present invention controls the density of multiple points of crystal grains of a semiconductor film formed on an insulating surface, and contains carbon after aggregating a metal element or a metal silicide on the surface of the multiple points. A field emission device having an electron emission portion formed of ultrafine carbon fiber is formed by heating or plasma treatment in an atmosphere.

  The electron emission portion formed in the present invention is formed on the surface of the cathode electrode of the field emission device. The cathode electrode is formed of a crystalline semiconductor film, and the electron emission part is ultrafine carbon such as CNT, carbon nanofiber, graphite nanofiber, tube-shaped graphite, carbon nanocone with a sharp tip, cone-shaped graphite, etc. It is made of fiber.

  In the present invention, as a method of forming a metal element or a metal silicide at multiple points of a crystalline semiconductor film, after adding a metal element on the amorphous semiconductor film, the amorphous semiconductor film is crystallized. Thus, a crystalline semiconductor film is formed, and a metal element or a metal silicide is formed at multiple points of crystal grains.

  In the present invention, as a method for forming a metal element or a metal silicide at multiple points of a crystalline semiconductor film, a metal element is added to the crystalline semiconductor film and then heated to form metal at multiple points of crystal grains. Form elemental or metal silicides.

  In the present invention, as a method of forming a metal element or a metal silicide at multiple points of a crystalline semiconductor film, a metal element is added to an amorphous semiconductor film, and then irradiated with laser light to be amorphous. The crystalline semiconductor film is crystallized, and a metal element or a metal silicide is formed at multiple points of crystal grains.

  In the present invention, the metal element promotes crystallization of the amorphous semiconductor film, and is typically nickel (Ni), iron (Fe), cobalt (Co), platinum (Pt), titanium. (Ti), palladium (Pd), etc. can be applied.

In the present invention, the ultrafine carbon fiber can be used to produce a probe of a scanning line probe microscope, a negative electrode material of a lithium battery, a gas storage material, an FET, and a semiconductor device having the FET.

  The diameter of the ultrafine carbon fiber can be controlled by the production method of the ultrafine carbon fiber of the present invention, and as a result, the ultrafine carbon fiber having a uniform diameter can be formed. In addition, a field emission device having an ultrafine carbon fiber with a uniform diameter as an electron emission portion can be formed. Further, the density of the electron emission portion of the field emission device can also be controlled. For this reason, it is possible to emit emission current uniformly in each pixel, and it is possible to form an FED capable of displaying without variation.

  In addition, since the ultrafine carbon fiber produced according to the present invention has a uniform diameter, it is possible to produce a highly reliable probe for a scanning line probe microscope, an FET, a negative electrode material for a lithium battery, a gas storage material, and the like. it can.

In addition, since the field emission device can be formed using a large-area substrate, the present invention is suitable for a mass production process. For this reason, a semiconductor device and a display device using ultrafine carbon fibers and ultrafine carbon fibers can be manufactured with high productivity.

  The best mode for carrying out the invention will be described below with reference to the drawings. However, the present invention can be implemented in many different modes, and those skilled in the art can easily understand that the modes and details can be variously changed without departing from the spirit and scope of the present invention. Is done. Therefore, the present invention should not be construed as being limited to the description of the embodiment modes. In the drawings, common portions are denoted by the same reference numerals, and detailed description thereof is omitted.

(First embodiment)

A method for producing an ultrafine carbon fiber will be described with reference to FIGS. FIG. 1 is a perspective view of a substrate on which an amorphous semiconductor film and a crystalline semiconductor film are formed. 3 is a cross-sectional view taken along the line II ′ of FIG.

  As shown in FIGS. 1A and 3A, an amorphous semiconductor film 102 is formed over a substrate 100 with a first insulating film 101 interposed therebetween.

The first insulating film 101 is mainly composed of silicon and oxygen by a known method (CVD method (chemical vapor deposition), PVD method (physical vapor deposition), etc.)). A film (a silicon oxide film, a silicon nitride oxide film, a silicon oxynitride film, or the like) is formed. The first insulating film can prevent diffusion of alkali metal such as sodium (Na) contained in a trace amount in the glass substrate.

An amorphous semiconductor film 102 is formed on the first insulating film by a known method (CVD method, PVD method, or the like). The amorphous semiconductor film includes silicon and is formed using a silicon film or silicon germanium (Si _1-x Ge _x (0 <x <1, typically x = 0.001 to 0.05)). The thickness of the amorphous semiconductor film is preferably in the range of 0.03 to 0.3 μm, but is not limited to this range.

  Next, as shown in FIG. 3A, a solution 103 containing 1 ppm to 1000 ppm of a metal element that promotes crystallization is applied to the surface of the amorphous semiconductor film. As the metal element, nickel (Ni), iron (Fe), cobalt (Co), platinum (Pt), titanium (Ti), palladium (Pd), or the like can be applied.

Next, as shown in FIGS. 1B and 3B, the amorphous semiconductor film is crystallized to form a crystalline semiconductor film 111. As the crystallization method, known methods (laser crystallization method, rapid thermal annealing method (RTA), thermal crystallization method using a furnace annealing furnace, etc.) can be used. Here, the amorphous semiconductor film is crystallized by a thermal crystallization method using a furnace annealing furnace. Since a solution containing a metal element that promotes crystallization is applied to the surface of the amorphous semiconductor film, crystallization is performed at a low temperature in a short time. Typically, the amorphous semiconductor film is heated at 400 to 1100 degrees, preferably 500 to 650 degrees for 1 minute to 12 hours. Through the crystallization step, the amorphous semiconductor film is crystallized to form the crystalline semiconductor film 111, and a metal element or metal silicide 112 is precipitated (aggregated, aggregated) on the surface of the crystal grain boundary (the triple point of the crystal grain). Segregation). Note that the density and size of the crystal grain boundary (the triple point of the crystal grain) can be controlled by crystallization conditions, such as the crystallization temperature, the hydrogen concentration in the film, the amount of metal element that promotes crystallization, and the like. It is. That is, by controlling the crystal grain boundary, the density and area of the metal element or metal silicide formed on the surface of the crystal grain boundary (the triple point of the crystal grain) can be controlled. As a result, it is possible to control the density and diameter of the ultrafine carbon fibers formed using these as nuclei.

  Next, as shown in FIGS. 1C and 3C, ultrafine carbon fibers are formed using a metal element or metal silicide 112 formed on the surface of the crystal grain boundary (the triple point of the crystal grains) as a catalyst. . The ultrafine carbon fiber is formed by heating to 100 to 1100 degrees, preferably 400 to 650 degrees in an atmosphere containing a hydrocarbon such as methane or acetylene decompressed to 1 to 760 torr. The ultrafine carbon fiber can also be formed by CVD using 1 to 760 torr using hydrocarbons such as methane or acetylene as a raw material. In this case, a negative voltage may be applied to the substrate side.

  Thereafter, the ultrafine carbon fibers 121 can be dissociated from the crystalline semiconductor film 111 by a lift-off method or the like, whereby ultrafine carbon fibers can be formed.

  Although a crystalline semiconductor film in which triple points are formed at the crystal grain boundary is shown here as the crystalline semiconductor film, the present invention is not limited to this, and the crystallinity that forms the four-point 11 at the crystal grain boundary as shown in FIG. The semiconductor film 12 or a crystalline semiconductor film having more multiple points may be formed. Note that even in this crystalline semiconductor film, metal elements or metal silicides are formed at four points or multiple points.

(Second Embodiment)

  Next, a method for producing ultrafine carbon fibers different from the above of the present invention will be described with reference to FIGS.

  4 is a cross-sectional view taken along the line II ′ of FIG. Similar to the first embodiment, a first insulating film 101 and an amorphous semiconductor film 102 are sequentially formed on a substrate 100. Next, this amorphous semiconductor film is crystallized. In this embodiment, a laser crystallization method is used as the crystallization method. A crystalline semiconductor film is formed by irradiating the amorphous semiconductor film 102 with laser light 104 using a gas laser oscillator, a solid-state laser oscillator, or a metal oscillator. As the laser light at this time, continuous wave or pulsed laser light can be used.

  Next, as shown in FIG. 4B, a thin film 132 containing a metal element is formed over the crystalline semiconductor film 131 by a known method (CVD method, PVD method, or the like). As this metal element, nickel (Ni), iron (Fe), cobalt (Co), platinum (Pt), titanium (Ti), palladium (Pd), or the like can be used. Here, a thin gold film having a thickness of 2 to 5 nm is formed by sputtering. Note that, instead of this step, a solution containing the above metal element can be applied over the crystalline semiconductor film.

  Next, as shown in FIGS. 1B and 4C, the crystal grains of the crystalline semiconductor film are typically heated at 100 to 1100 degrees, preferably 400 to 600 degrees for 1 to 5 hours. A metal element or metal silicide 112 is deposited (aggregated or segregated) on the surface of the boundary (triple point of crystal grains). Note that the crystal grain boundary of the crystalline semiconductor film formed using laser light varies depending on laser irradiation conditions as shown in FIG. FIG. 12 shows a density at a triple point when an amorphous silicon film having a thickness of 50 nm is irradiated with a XeCl laser. It can be seen that the density of the triple point varies depending on the energy density of the laser beam and the number of shots. By controlling these, the density of the triple point and the density of the metal element or metal silicide formed therein can be controlled. Further, the size of the metal element or metal silicide aggregated at the triple point can be controlled by the thickness of the metal thin film formed over the crystalline semiconductor film or the concentration of the solution containing the metal element. That is, it is possible to control the density and diameter of the ultrafine carbon fiber formed using these as nuclei.

  Note that the surface of the crystalline semiconductor film 131 may be hydrogenated before the thin film 132 including a metal element is formed. By this step, the size of the metal element or metal silicide formed at the triple point can be further reduced.

  Next, as shown in FIGS. 1C and 4D, ultrafine carbon fibers 121 are formed using a metal element or metal silicide as a catalyst. The ultrafine carbon fiber is formed by heating to 100 to 1100 degrees, preferably 400 to 650 degrees in an atmosphere containing a hydrocarbon such as methane or acetylene decompressed to 1 to 760 torr. Alternatively, a hydrocarbon such as methane or acetylene can be used as a raw material for the ultrafine carbon fiber, and the film can be formed by CVD at 1 to 760 torr. In this case, a negative voltage may be applied to the substrate side.

  Thereafter, the ultrafine carbon fiber can be formed by dissociating the ultrafine carbon fiber from the crystalline semiconductor film by a lift-off method or the like.

(Third embodiment)

Next, a method for producing ultrafine carbon fibers different from the above of the present invention will be described.

5 is a cross-sectional view taken along the line II ′ of FIG. 1 as in FIGS. Similar to the first embodiment, a first insulating film 101 and an amorphous semiconductor film 102 are sequentially formed on a substrate 100.

  Next, as shown in FIG. 5A, a solution 103 containing 1 ppm to 1000 ppm of a metal element is applied to the surface of the amorphous semiconductor film. As the metal element, nickel (Ni), iron (Fe), cobalt (Co), platinum (Pt), titanium (Ti), palladium (Pd), or the like can be applied.

  Next, the amorphous semiconductor film is crystallized. Here, a laser crystallization method is used as the crystallization method. A crystalline semiconductor film is formed by irradiating the amorphous semiconductor film 102 with laser light 104 using a gas laser oscillator, a solid laser oscillator, or a metal laser oscillator, and a metal element or a metal silicide 112 is applied to the crystalline semiconductor film. It is precipitated (aggregated and segregated) on the surface of the crystal grain boundary (triple point). As the laser light at this time, continuous wave or pulsed laser light can be used (FIG. 5A).

The density and size of the crystal grain boundary (the triple point of the crystal grain) depends on the crystallization conditions, such as the energy density of the laser beam, the number of shots, the hydrogen concentration in the film, the amount of the metal element that promotes crystallization, It is possible to control. That is, by controlling the crystal grain boundary, the density and area of the metal element or metal silicide formed on the surface of the crystal grain boundary (the triple point of the crystal grain) can be controlled. That is, it is possible to control the density and diameter of the ultrafine carbon fiber formed using these as nuclei.

  Next, as shown in FIGS. 1C and 5C, ultrafine carbon fibers 121 are formed using a metal element or metal silicide as a catalyst. The ultrafine carbon fiber is formed by heating to 100 to 1100 degrees, preferably 400 to 650 degrees in an atmosphere containing a hydrocarbon such as methane or acetylene decompressed to 1 to 760 torr. Alternatively, a hydrocarbon such as methane or acetylene can be used as a raw material, and it can be formed by a CVD method at 1 to 760 torr. In this case, a negative voltage may be applied to the substrate side.

  Thereafter, the ultrafine carbon fiber can be formed by dissociating the ultrafine carbon fiber from the crystalline semiconductor film by a lift-off method or the like.

(Fourth embodiment)

    Here, a structure of a field emission element, a display device including the field emission element, and a manufacturing method thereof are described. The field emission device of the present invention comprises a cathode electrode and an electron emission portion formed on the surface thereof. The cathode electrode is formed of a crystalline semiconductor film, and the electron emission part is an ultrafine carbon fiber such as graphite nanofiber, carbon nanofiber, carbon nanotube, tube-shaped graphite, carbon nanocone with a sharp tip, cone-shaped graphite, etc. Can be adapted.

  In this embodiment mode, a structure of a field emission element of a bipolar tube type FED, a display device including the field emission element, and a manufacturing method thereof will be described. Specifically, it is formed of ultrafine carbon fiber at the point where the stripe-shaped cathode electrode formed on the first substrate and the stripe-shaped anode electrode formed on the second substrate intersect. A field emission display device having an electron emission portion will be described with reference to FIGS. Here, the production process of the ultrafine carbon fiber shown in the second embodiment is applied to the production process of the electron emission portion. Instead of this process, the manufacturing process shown in the first embodiment or the third embodiment may be applied.

  FIG. 6 is a perspective view of a part of the display panel. A striped cathode electrode 202 formed of a crystalline semiconductor film is formed on the first substrate 200, and an electron emission portion 205 formed of ultrafine carbon fiber is formed thereon. On the other hand, a striped anode electrode 207 and a phosphor layer 206 are formed on the second substrate 203. An electric field is applied in a region where the first substrate anode electrode and the cathode electrode of the second substrate intersect each other with a predetermined distance, and electrons are emitted from the electron emission portion of the cathode electrode to the anode electrode.

  FIG. 7 is a cross-sectional view of the first substrate 200 shown in FIG. A method for manufacturing the cathode electrode and the electron emission portion will be described with reference to FIGS. In addition, the same part as FIG. 6 is shown using the same code | symbol.

  As shown in FIG. 7A, a first insulating film 201 is formed over a first substrate 200, and an amorphous semiconductor film 211 is formed by a known method (CVD method, PVD method, or the like). After that, the amorphous semiconductor film 211 is irradiated with laser light 213 using a gas laser oscillator, a solid-state laser oscillator, or a metal oscillator to form a crystalline semiconductor film. As the laser light at this time, continuous wave or pulsed laser light can be used.

  Next, as shown in FIG. 7B, the crystalline semiconductor film is etched to form a cathode electrode 202 formed of a striped crystalline semiconductor film. Next, a thin film containing a metal element is formed on the cathode electrode formed of a crystalline semiconductor film by a known method (CVD method, PVD method, or the like). As this metal element, nickel (Ni), iron (Fe), cobalt (Co), platinum (Pt), titanium (Ti), palladium (Pd), or the like can be used. Here, a thin gold film having a thickness of 2 to 5 nm is formed by sputtering.

  Next, the metal element of the metal thin film is heated at 100 to 1100 ° C., preferably 400 to 600 ° C. for 1 to 5 hours to segregate on the surface of the crystal grain boundary (crystal triple point) of the crystalline semiconductor film ( Region 221). Thereafter, the metal thin film formed between the cathode electrodes 202 is removed.

  Note that the surface of the crystalline semiconductor film may be hydrogenated before the thin film containing a metal element is formed. By this step, the size of the metal element or metal silicide formed at the triple point can be further reduced.

  Next, as shown in FIG. 7C, an electron emission portion 205 formed of ultrafine carbon fiber is formed using a metal element or metal silicide (region 221) as a catalyst. Here, the electron emission portion 205 is formed by heating to 100 to 1100 degrees, preferably 400 to 650 degrees, in an atmosphere containing a hydrocarbon such as methane or acetylene decompressed to 1 to 760 torr. Alternatively, a hydrocarbon such as methane or acetylene may be used as a raw material, and the electron emission portion 205 may be formed by a CVD method at 1 to 760 torr. In this case, a negative voltage may be applied to the substrate side. Since the diameter and density of the electron emission portion can be controlled by the manufacturing process of the electron emission portion of this embodiment, it is possible to form an FED substrate that can emit an emission current uniformly in each pixel. It becomes possible.

  Note that an impurity element imparting n-type conductivity is preferably added to the cathode electrode 202 formed of a crystalline semiconductor film in order to increase conductivity. As the impurity element imparting n-type conductivity, an element belonging to Group 15, typically phosphorus (P) or arsenic (As) can be used.

Next, as shown in FIG. 6, a phosphor layer 206 is formed on the second substrate 203 by a known method, and a conductive film having a thickness of 0.05 to 0.1 μm is formed thereon, and then a stripe shape is formed. The anode electrode 207 is formed. The conductive film may be a thin film made of a metal element such as aluminum, nickel, silver, or ITO (indium tin oxide alloy), indium zinc oxide alloy (In ₂ O ₃ ) -ZnO), zinc oxide (ZnO). A transparent conductive film such as a film can be formed by a known method, and a known patterning technique can be used.

  The phosphor layer 206 includes a red phosphor layer, a blue phosphor layer, and a green phosphor layer, and one set of these phosphor layers constitutes one pixel. A black matrix may be formed between the phosphor layers in order to increase the contrast. The anode electrode may be formed on each phosphor layer, or may be formed on a pixel composed of a red phosphor layer, a blue phosphor layer, and a green phosphor layer.

  The first substrate and the second substrate formed in the above steps are sealed with an adhesive member, and a portion surrounded by the substrate and the sealing member is decompressed to form a field emission display panel.

  The field emission display device here is a passive driving method. In FIG. 6, the cathode electrode 202 formed on the first substrate 200 is connected to the cathode electrode driving circuit, and the anode electrode 207 formed on the second substrate 203 is connected to the anode electrode driving circuit. . A relatively negative voltage is applied from the cathode electrode drive circuit through the cathode electrode, and a relatively positive voltage is applied to the anode electrode from the anode electrode drive circuit. In accordance with the electric field generated by applying these voltages, electrons are emitted from the tip of the electron emission portion based on the quantum tunnel effect and are induced to the anode electrode. When the electrons collide with the phosphor layer formed on the anode electrode, the phosphor layer is excited to emit light and display can be obtained. Note that the cathode electrode driving circuit and the anode electrode driving circuit can be formed in the extended portion on the first substrate. Also, an external circuit such as an IC chip can be used. Through the above steps, a field emission display device can be formed.

  Through the above process, a field emission device having a cathode electrode and an electron emission portion formed of ultrafine carbon fibers on the surface thereof, and a display device having the same are formed. Although the cathode electrode is striped here, the cathode electrode and the anode electrode may be planar and used for an area color display device.

(Fifth embodiment)

  Next, the structure and manufacturing method of a triode-type FED field emission device and a field emission display device having the same will be described with reference to FIGS. Here, the field emission element is 1) a cathode electrode formed by a semiconductor film etched in stripes and having n-type conductivity, and 2) a gate electrode facing the cathode electrode through an interlayer insulating film. 3) It includes an opening part of the gate electrode and the insulating film, and an electron emission part formed of ultrafine carbon fiber on the surface of the cathode electrode. Here, the production process of the ultrafine carbon fiber described with reference to the second embodiment is applied to the production process of the electron emission portion. Instead of this process, a process using the first embodiment or the third embodiment may be applied.

  FIG. 8 is a perspective view of a part of the display panel. On the first substrate 301, a stripe-shaped cathode electrode 302 formed of a semiconductor film and a stripe-shaped gate electrode 303 are formed via an insulating film (not shown). The cathode electrode 302 and the gate electrode 303 are orthogonal to each other through an insulating film. An opening 307 is formed at the intersection of the cathode electrode and the gate electrode, and an electron emission portion 308 made of ultra fine carbon fiber is formed on the surface of the cathode electrode in the opening. A phosphor layer 304 and an anode electrode 306 are formed on the second substrate 305.

  FIG. 9 is a cross-sectional view of the first substrate 301 in FIG. A method for manufacturing a field emission device will be described with reference to FIGS.

  As shown in FIG. 9A, a first insulating film 311 is formed over a first substrate 301, and an amorphous semiconductor film is formed thereover. Next, the amorphous semiconductor film is irradiated with laser light, so that the crystalline semiconductor film 312 is formed.

  Thereafter, as shown in FIG. 9B, a resist mask (not shown) is formed in a portion where the cathode electrode is to be formed, and then the exposed crystalline semiconductor film is etched to form a stripe-shaped cathode electrode. A cathode electrode 302 formed of a crystalline semiconductor film is formed.

  Next, a second insulating film 321 is formed over the cathode electrode 302 formed using a crystalline semiconductor film. As the second insulating film, a film containing silicon and oxygen as main components (silicon oxide film, silicon nitride oxide film, silicon oxynitride film, etc.) formed by a known method (CVD method, PVD method, etc.), or An organic resin film formed by a coating method is used.

  Next, an impurity element imparting n-type conductivity is added to the cathode electrode 202 formed of a crystalline semiconductor film in order to increase the first conductivity. As the impurity element imparting n-type conductivity, an element belonging to Group 15, typically phosphorus (P) or arsenic (As) can be used. Note that the step of adding the n-type impurity may be performed before the second insulating film is formed.

Next, a first conductive film 322 is formed. As the first conductive film, tungsten (W),
Metals such as niobium (Nb), tantalum (Ta), molybdenum (Mo), chromium (Cr), aluminum (Al), copper (Cu), or alloys or compounds containing these metal elements (such as titanium nitride and tantalum nitride) Nitride, silicides such as tungsten silicide, titanium silicide, and manganese silicide, translucent conductive films such as ITO and IZO, and the like can be used. A resist mask is formed on the first conductive film and patterned to remove unnecessary portions, thereby forming a stripe-shaped gate electrode.

  Next, as shown in FIG. 9C, after patterning by forming a resist mask in a desired shape in a region where the cathode electrode and the gate electrode intersect with each other through the second insulating film, The gate electrode and the second insulating film are etched into an arbitrary shape to expose the semiconductor film, and an opening 307 is formed.

  Next, a metal thin film having nickel (Ni), cobalt (Co), platinum (Pt), iron (Fe), titanium (Ti), or palladium (Pd) element having a thickness of 2 to 5 nm on the surface of the crystalline semiconductor film 331 is formed by a known method (a CVD method, a sputtering method, a vacuum evaporation method, or the like). Thereafter, heating is performed at 100 to 1100 degrees, preferably 400 to 600 degrees for 1 to 5 hours, so that a metal element or a metal silicide 341 is precipitated at a crystal grain boundary (triple point of crystal grains) (FIG. 9D). ).

 Next, as shown in FIG. 9E, an electron emission portion 308 formed of ultrafine carbon fiber is formed using a metal element or metal silicide as a catalyst. The ultrafine carbon fiber is formed by heating to 100 to 1100 degrees, preferably 400 to 650 degrees in an atmosphere containing a hydrocarbon such as methane or acetylene decompressed to 1 to 760 torr. Alternatively, a hydrocarbon such as methane or acetylene can be used as a raw material for the ultrafine carbon fiber, and the film can be formed by CVD at 1 to 760 torr. In this case, a negative voltage may be applied to the substrate side.

  Note that the surface of the crystalline semiconductor film may be hydrogenated before the thin film containing a metal element is formed. By this step, the size of the metal element or metal silicide formed at the triple point can be further reduced. Since the diameter and density of the electron emission portion can be controlled by the manufacturing process of the electron emission portion of this embodiment, it is possible to form an FED substrate that can emit an emission current uniformly in each pixel. It becomes possible.

  In FIG. 8, 2 × 2 openings are shown at the intersection 309 between the cathode electrode and the gate electrode, but the present invention is not limited to this, and one opening or multiple openings are formed. May be.

  Through the above steps, a substrate having a field emission element having an electron emission portion formed of ultrafine carbon fibers can be formed on the first substrate.

In FIG. 8, the first insulating film 311 and the second insulating film 321 shown in FIG. 9 are omitted.

  As shown in FIG. 8, a phosphor layer 304 is formed on a second substrate 305 by a known method, and a third conductive film having a thickness of 0.05 to 0.1 μm is formed thereon, which is desired. The anode electrode 306 is formed by etching into the shape (stripe shape, matrix shape). The phosphor layer 304 can be formed of the same material and structure as the phosphor layer 206 shown in FIG. Further, the anode electrode 306 can have the same material and structure as the anode electrode 207 shown in FIG.

  The first substrate and the second substrate formed in the above steps are sealed with an adhesive member, and a portion surrounded by the substrate and the sealing member is decompressed to form a display panel of the field emission display device.

  The driving method of the field emission display device formed in the above process is a passive driving method. As shown in FIG. 8, the cathode electrode 302 is connected to the cathode electrode drive circuit, the gate electrode 303 is connected to the gate electrode drive circuit, and the anode electrode 306 is connected to the anode electrode drive circuit. . A relatively negative voltage (for example, 0 kV) is applied to the cathode electrode from the cathode electrode drive circuit, and a relatively positive voltage (for example, 50 V) is applied to the gate electrode from the gate electrode drive circuit. In accordance with the electric field generated by applying these voltages, electrons are emitted from the tip of the electron emission portion based on the quantum tunnel effect. A voltage higher than the positive voltage applied to the gate electrode (for example, 1 kV) is applied to the anode electrode by the anode electrode driving circuit, and the electrons emitted from the field emission device are formed on the anode electrode. Guide to layer. When the electrons collide with the phosphor layer, the phosphor layer is excited to emit light and display can be obtained. Note that it is also possible to form the cathode electrode driving circuit and the gate electrode driving circuit simultaneously with the formation of the field emission element on the first substrate. Also, an external circuit such as an IC chip can be used.

  Through the above steps, a field emission display device can be formed.

(Sixth embodiment)

Next, a triode FED field emission device will be described with reference to FIGS. The field emission device described here includes 1) a semiconductor region having a source region and a drain region, etched into a desired shape, 2) a source electrode and a source wiring in contact with the source region of the semiconductor region, and 3) an interlayer insulating film. A gate electrode and a gate wiring that oppose the semiconductor film and controls the carrier concentration between the source region and the drain region of the semiconductor film. An electron emission portion formed of ultrafine carbon fiber on the surface.

  A phosphor layer 406 and an anode electrode 407 are formed on the second substrate 405.

  FIG. 11 is a sectional view of the knee ′ of FIG. A method for manufacturing the field emission device of this embodiment mode will be described with reference to FIGS.

  As shown in FIG. 11A, a first insulating film 411 is formed over the first substrate 400. Next, a crystalline semiconductor film is formed by a known method as described in FIG. 3, and a part of the crystalline semiconductor film is etched to form a semiconductor region having a desired shape (region 401 in FIG. 10).

  Next, a second insulating film 412 is formed on the first substrate by a known method. The second insulating film is formed using a film containing silicon and oxygen as main components (a silicon oxide film, a silicon nitride oxide film, a silicon oxynitride film, or the like).

  Next, a first conductive film is formed. The first conductive film can be formed using a material similar to that of the first conductive film 322 in FIG. Next, a resist mask is formed over the first conductive film, and patterning is performed. Unnecessary portions are removed, and a gate electrode and a gate wiring 402 are formed. Next, an impurity imparting n-type conductivity is added to part of the crystalline semiconductor film using the gate electrode as a mask, so that the source region 401a and the drain region 401b are formed.

  Next, as shown in FIG. 11B, a third insulating film 421 is formed. As the third insulating film, a film containing silicon and oxygen as main components (silicon oxide film, silicon nitride oxide film, silicon oxynitride film, etc.) formed by a known method (CVD method, PVD method, etc.), or An organic resin film formed by a coating method is used.

  Next, part of the third insulating film 421 and the second insulating film 412 is etched, and a conductive film is formed over the first substrate. Next, this conductive film is etched into a desired shape to form a source wiring and a source electrode 403.

  Next, as illustrated in FIG. 11C, after the fourth insulating film 431 is formed over the first substrate, the fourth insulating film, the third insulating film, and the second insulating film are formed. A part is etched to expose a part of the semiconductor region. Thereafter, a metal thin film 432 having a thickness of 2 to 5 nm is formed on the substrate by a known method (CVD method, PVD method, etc.). As this metal element, nickel (Ni), iron (Fe), cobalt (Co), platinum (Pt), titanium (Ti), palladium (Pd), or the like can be used.

Next, heating is performed at 100 to 1100 degrees, preferably 400 to 650 degrees for 1 to 5 hours, so that a metal element or a metal silicide is precipitated at the grain boundaries (multiple points).

Next, as shown in FIG. 11D, an electron emission portion 404 formed of ultrafine carbon fibers is formed using a metal element or metal silicide as a catalyst. The ultrafine carbon fiber is formed by heating to 100 to 1100 degrees, preferably 400 to 650 degrees in an atmosphere containing a hydrocarbon such as methane or acetylene decompressed to 1 to 760 torr. The ultrafine carbon fiber can also be formed by a CVD method using 1 to 760 torr of hydrocarbon such as methane or acetylene as a raw material. In this case, a negative voltage may be applied to the substrate side. Since the diameter and density of the electron emission portion can be controlled by the manufacturing process of the electron emission portion of this embodiment, it is possible to form an FED substrate that can emit an emission current uniformly in each pixel. It becomes possible.

In FIG. 10, the first insulating film 411, the second insulating film 412, the third insulating film 421, and the fourth insulating film 431 shown in FIG. 11 are omitted. Further, in FIG. 11, after the metal thin film 432 is formed without forming the fourth insulating film 431, etching may be performed so as to insulate the source region and the drain region.

  The first substrate formed by the above process and the second substrate 305 shown in FIG. 8 of the fifth embodiment are sealed with an adhesive member, and the portion surrounded by the substrate and the sealing member is decompressed. A display panel of a field emission display device is formed.

  Thereafter, as shown in FIGS. 8 and 9, a field emission display device can be formed.

  Through the above steps, a field emission comprising a semiconductor region having a source region and a drain region, a source electrode and a source wiring in contact with the source region, a gate electrode, and an electron emission portion formed of carbon on the surface of the drain region of the semiconductor region. An element is formed. Since the field emission device formed in this embodiment has a transistor structure, each field emission device has switching characteristics. Therefore, display for each pixel can be controlled.

  Further, in order to more accurately control ON / OFF of the field emission element, each field emission element may be provided with a switching element such as a thin film transistor or a diode.

  In the present embodiment, the field emission device is described using the top gate structure, but the present invention is not limited to this, and the field emission device can be similarly formed even in the bottom gate structure.

(Seventh embodiment)
Here, an application example of the ultrafine carbon fiber shown in the embodiment is proposed. Application of the ultrafine carbon fiber formed in any one of the first to third embodiments to the channel region of a scanning probe microscope (SPM) and FET (Field Effect Transistor) can do. Note that an FET (also referred to as a TUBEFET) using an ultrafine carbon fiber for a channel formation region is formed of an insulating film on a conductive layer such as a silicon substrate, a metal film, or a metal substrate, and is formed of gold or platinum thereon. The source electrode and the drain electrode are formed, and the electrodes are formed by bridging the electrodes with ultrafine carbon fibers. In addition, ultrafine carbon fibers can be applied to negative electrode materials, gas storage materials, etc. for lithium batteries by taking advantage of the structure of one-dimensional pores with essentially large spaces in and between tubes. .

(Eighth embodiment)
Here, a semiconductor device using the ultrafine carbon fiber shown in the embodiment is proposed. A semiconductor device in which an FET (TUBEFET) having the ultrafine carbon fiber produced in any of the first to third embodiments in a channel region is highly integrated, typically a signal line driver circuit, a controller, a CPU, and a sound processing circuit Semiconductor devices such as converters, power supply circuits, transmission / reception circuits, memories, audio processing circuit amplifiers, video detection circuits, video processing circuits, and audio detection circuits can be formed. In addition, a system-on-chip that is monolithically equipped with circuits that constitute a single system (functional circuit) such as an MPU (microcomputer), memory, and I / O interface, enabling high speed, high reliability, and low power consumption. Can be formed. Since these semiconductor devices or system-on-chip are formed using ultrafine carbon fibers manufactured with high reliability, they can be manufactured with high yield.

(Ninth embodiment)
Various electronic devices can be manufactured by incorporating the semiconductor device, the system on chip, the display device, and the like described in the above embodiment into a housing. Electronic devices include television devices, video cameras, digital cameras, goggles-type displays (head-mounted displays), navigation systems, sound playback devices (car audio, audio components, etc.), notebook-type personal computers, game machines, and portable information terminals (Mobile computer, mobile phone, portable game machine, electronic book, or the like), an image playback apparatus equipped with a recording medium (specifically, a recording medium such as a digital versatile disc (DVD) can be played back and the image can be displayed. And a device equipped with a display). Here, a television device is shown in FIG. 13 as a typical example of these electronic devices.

  FIG. 13 is a perspective view of the television device as viewed from the front, and includes a housing 1151, a display portion 1152, a speaker portion 1153, an operation portion 1154, a video input terminal 1155, and the like.

  The display unit 1152 is an example of a video output unit, and displays a video here.

  The speaker unit 1153 is an example of an audio system output unit, and outputs audio here.

  The operation unit 1154 is provided with a power switch, a volume switch, a channel selection switch, a tuner switch, a selection switch, and the like. By pressing the button, the power of the television apparatus is turned on / off, video selection, audio adjustment, And selecting a tuner. Although not shown, the above selection can also be performed by a remote controller type operation unit.

  The video input terminal 1155 is a terminal for inputting a video signal from the outside such as a VTR, a DVD, or a game machine to the television apparatus.

In the case where the television device shown in the present embodiment is a wall-mounted television device, a wall-hanging portion is provided on the back surface of the main body.

By using the display device which is an example of the semiconductor device of the present invention for the display portion of the television device, a high-quality television device without variation can be manufactured. In addition, a television device can be manufactured with high yield by using the semiconductor device of the present invention for a video detection circuit, a video processing circuit, an audio detection circuit, an audio processing circuit, and a CPU for controlling these in the television device. Can do. For this reason, the television device can be applied to various uses as a display medium of various large areas, such as a wall-mounted television device, an information display board in a railway station or airport, and an advertisement display board in a street.

The perspective view explaining the preparation process of the ultrafine carbon fiber which concerns on this invention. FIG. 6 is a cross-sectional view illustrating a crystalline semiconductor film according to the present invention. Sectional drawing explaining the manufacturing process of the ultra-fine carbon fiber which concerns on this invention. Sectional drawing explaining the manufacturing process of the ultrafine carbon fiber which concerns on this invention Sectional drawing explaining the manufacturing process of the ultra-fine carbon fiber which concerns on this invention. 1 is a perspective view illustrating a display panel of a field emission display device according to the present invention. Sectional drawing explaining the manufacturing process of the field emission element which concerns on this invention 1 is a perspective view illustrating a display panel of a field emission display device according to the present invention. Sectional drawing explaining the manufacturing process of the field emission element which concerns on this invention. 1 is a perspective view illustrating a display panel of a field emission display device according to the present invention. Sectional drawing explaining the manufacturing process of the field emission element which concerns on this invention. The figure which shows the density of a triple point. FIG. 9 illustrates an electronic device.

Claims (27)

  A semiconductor film is formed on the surface having an insulating property, a metal element is added to the semiconductor film, a metal element or a metal silicide is segregated at a crystal grain boundary of the semiconductor film by the first treatment, and then a second A method for producing an ultrafine carbon fiber, characterized in that an ultrafine carbon fiber is formed on the surface of the metal element or metal silicide by treatment.   2. The method for manufacturing an ultrafine carbon fiber according to claim 1, wherein the semiconductor film is an amorphous semiconductor film, and the first treatment includes a step of crystallizing the amorphous semiconductor film.   3. The ultrafine carbon fiber according to claim 1, wherein the semiconductor film is an amorphous semiconductor film, and the first treatment is heating at 400 to 1100 degrees or laser light irradiation. Manufacturing method.     The method for manufacturing an ultrafine carbon fiber according to claim 1, wherein the semiconductor film is a crystalline semiconductor film, and the first treatment is heating at 100 to 1100 degrees.   5. The method for manufacturing an ultrafine carbon fiber according to claim 1, wherein the second treatment is performed by heating at 100 to 1100 degrees in an atmosphere containing a hydrocarbon.   6. The method for manufacturing an ultrafine carbon fiber according to claim 1, wherein the second treatment is a chemical vapor deposition method using a hydrocarbon as a raw material.     7. The method for producing an ultrafine carbon fiber according to claim 1, wherein the crystal grain boundary is a multiple point of crystal grains.   8. The method for manufacturing an ultrafine carbon fiber according to claim 1, wherein the ultrafine carbon fiber is dissociated from the semiconductor film after the ultrafine carbon fiber is formed. 9. 9. The method for manufacturing an ultrafine carbon fiber according to claim 1, wherein the metal element is nickel, iron, cobalt, or platinum. 10. The ultrafine carbon fiber according to claim 1, wherein the ultrafine carbon fiber is a graphite nanofiber, a carbon nanofiber, a carbon nanotube, a tube-like graphite, a carbon nanocone, or a cone-like graphite. Method for producing ultrafine carbon fiber.   A semiconductor film is formed on the surface having an insulating property, a metal element is added to the semiconductor film, a metal element or a metal silicide is segregated at a crystal grain boundary of the semiconductor film by the first treatment, and then a second A method of manufacturing a field emission device, comprising forming an electron emission portion formed of ultrafine carbon fiber on a surface of the metal element or metal silicide by treatment.   12. The method for manufacturing a field emission device according to claim 11, wherein the semiconductor film is formed in a stripe shape.   After forming a semiconductor film having a desired shape over the insulating surface, a first insulating film is formed, and a first conductive film having a desired shape is formed over the first insulating film. Thereafter, a part of the first conductive film and the first insulating film is removed to expose the semiconductor film, a metal thin film is formed on the exposed semiconductor film, and then the first process is performed. An electric field characterized by segregating a metal element or metal silicide at a crystal grain boundary of a semiconductor film and forming an electron emission portion formed of ultrafine carbon fibers by a second treatment on the surface of the metal element or metal silicide. A method for manufacturing an emission element.   14. The field emission device according to claim 13, wherein the first conductive film having the desired shape is orthogonal to the semiconductor film having the desired shape with the first insulating film interposed therebetween. Method.   15. The method for manufacturing a field emission element according to claim 13, wherein the semiconductor film having the desired shape and the first conductive film having the desired shape are in a stripe shape.   16. The method for manufacturing a field emission element according to claim 11, wherein the semiconductor film has n-type conductivity.   After forming a semiconductor film having a desired shape over the insulating surface, a first insulating film is formed, and a first conductive film having a desired shape is formed over the first insulating film. After forming the source region and the drain region in the semiconductor film, a second insulating film is formed, and a part of the second insulating film and the first insulating film is removed to remove the source region of the semiconductor film. Is exposed to form a second conductive film, and the second insulating film and a part of the first insulating film are removed to expose a drain region of the semiconductor film, thereby exposing the exposed semiconductor film. After the metal thin film is formed on the surface, the metal element or metal silicide is segregated on the crystal grain boundary of the semiconductor film by the first treatment, and the surface of the metal element or metal silicide is made of ultrafine carbon fiber by the second treatment. Fabrication of a field emission device characterized by forming an electron emission portion to be formed Law.   18. The method for manufacturing a field emission element according to claim 17, wherein the source region and the drain region of the semiconductor film have n-type conductivity.   19. The method for manufacturing a field emission element according to claim 17, wherein the first conductive film is a gate electrode, and the second conductive film is a source electrode.   20. The semiconductor device according to claim 11, wherein the semiconductor film is an amorphous semiconductor film, and the first treatment includes a step of crystallizing the amorphous semiconductor film. A method for manufacturing a field emission device.   The semiconductor film according to any one of claims 11 to 20, wherein the semiconductor film is an amorphous semiconductor film, and the first treatment is heating at 400 to 1100 degrees or laser light irradiation. A method for manufacturing a field emission device.   The field emission device according to any one of claims 11 to 21, wherein the semiconductor film is a crystalline semiconductor film, and the first treatment is performed at 100 to 1100 degrees. Manufacturing method.   23. The method for manufacturing a field emission element according to claim 11, wherein the second treatment is performed by heating at 100 to 1100 degrees in an atmosphere containing a hydrocarbon.   24. The method for manufacturing a field emission element according to claim 11, wherein the second treatment is a chemical vapor deposition method using a hydrocarbon as a raw material.     25. The method for manufacturing a field emission device according to claim 11, wherein the crystal grain boundary is a multiple point of crystal grains.   26. The method for manufacturing a field emission element according to claim 11, wherein the metal element is nickel, iron, cobalt, platinum, titanium, or palladium. 27. The electron emission portion formed of the ultrafine carbon fiber according to claim 11, wherein the electron emission portion is a graphite nanofiber, a carbon nanofiber, a carbon nanotube, a tube-like graphite, a carbon nanocone, or a cone-like graphite. A method for manufacturing a field emission device, wherein:

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