JP3502804B2 - Method for growing carbon nanotubes and method for manufacturing electron gun and probe using the same - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for growing carbon nanotubes and an electron gun and probe manufacturing method using the same.

[0002]

BACKGROUND OF THE INVENTION For example, as a device using a cold cathode as an electron emission source (electron gun),
FED (Field Emission Display) is known. F
The ED is a display that causes electrons emitted in a vacuum by field emission to enter a phosphor and emit light. The light emission principle of FED is CRT (Cathode Ray
Tube) but the CRT scans an electron beam from a point electron source onto a two-dimensional phosphor, whereas
Since the ED has a planar electron source in which a large number of field emission electron sources (Field Emitters) are arranged, it is possible to form an extremely thin panel with low power consumption. The FED is a self-luminous display that does not require external light (backlight in the case of a transmissive type, external light in the case of a reflective type) unlike a liquid crystal display device, and has a thin, wide viewing angle and a bright screen. It can be provided, and has high luminous efficiency and does not require a light source, and thus consumes less power.

In the FED, a gate electrode (also called a grid) extracts electrons from the emitter,
The electrons are made incident on the anode on which the phosphor is formed. By controlling the voltage applied to this gate electrode,
The amount of electrons emitted from the emitter is controlled, and gradation display is possible.

In FEDs, electron emission from the emitter follows the Fowler-Nordheim rule. According to this Fowler-Nordheim equation, it is said that the operating voltage can be reduced by reducing the tip radius of the emitter electrode, bringing the emitter and gate closer, and using a material with a low work function for the emitter. There is.

The FED that has been put into practical use uses a cone-shaped emitter cone called a Spindt type made of Mo as a field emission electron source. By concentrating the voltage on the sharp portion of the emitter cone, it is easy to extract electrons.

The Spindt type emitter is disclosed in Japanese Patent Laid-Open No. 8-1.
48083, JP-A-8-202286, JP-A-8-30
6327, JP-A-9-245618, and JP-A-10-50.
240 and Japanese Patent Laid-Open No. 10-208649.

In the Spindt type emitter, the ability to emit electrons into a vacuum depends on the shape of the three-dimensional structure, and particularly on the apex angle or tip diameter of the emitter cone.

However, in the current fine processing technology, the diameter of the tip of the emitter cone is around 10 nm, and there is room for further improvement. In addition, it is difficult to form an emitter cone with a fine pattern of about 10 nm, and the size of the exposure apparatus naturally limits the increase in area. In particular, it is difficult to produce a panel of several tens of inches or more using the current photolithography technology. Met.

Since molybdenum (Mo) and the like have a large work function, a technique for forming a film of diamond-like carbon having a low work function on the surface of the cathode is also provided (Japanese Patent Laid-Open Nos. 10-312736 and 10-1998). 502
06, JP-A-10-134701, JP-A-10-199.
398).

However, even if the surface of the emitter edge from which atoms are emitted is covered with a material having a low work function, the tip diameter of the emitter cone is still around 10 nm, and the problem of sharpening still remains.

Applied Physics Vol. 67, No. 12 (1998), pp. 1390 to 1394, anisotropic chemical etching (ODE) or reactive ion etching (RIE) for forming Si emitter cones. There is also reported an experiment in which the Si emitter cone is sharpened by performing low temperature thermal oxidation after the etching treatment.

However, it is extremely difficult in practice to uniformly perform this ultrafine processing on a large amount of Si emitter cones on the substrate.

It has been proposed to use carbon nanotubes as an emitter to solve both the sharpening of the emitter edge and the use of a material having a low work function. The use of carbon nanotubes as an emitter is disclosed in JP-A-10-208677 and JP-A-10-19.
9398 and the above-mentioned Applied Physics Vol. 67, No. 12 (199
8) and the like.

Japanese Unexamined Patent Publication No. 10-208677 and Applied Physics Vol. 67, No. 12 describe arranging carbon nanotubes vertically. Although there is no direct disclosure of the disposing method in each of the above-mentioned documents, it was necessary to collect the carbon nanotubes formed by using arc discharge with a solution or the like, and stick them on the substrate in the same direction.

However, it is difficult to handle nano-sized carbon nanotubes and the quality (length, length,
It is practically impossible to mass-produce carbon nanotubes with uniform diameter, chirality, electrical resistance, etc.) and attach them to a substrate. If the carbon nanotube is lengthened in consideration of handling (Japanese Patent Laid-Open No. 10-20867).
7 has a vertically oriented diameter of 10 nm and a length of 1 μm) and has a large electric resistance, and a large amount of carbon nanotubes are required to secure a sufficient current as an emitter.

Japanese Unexamined Patent Publication (Kokai) No. 10-199398 describes that carbon nanotubes can be deposited on the cathode by a method such as discharge of a carbon material by arc plasma or laser ablation.

However, there is no disclosure about a method of depositing carbon nanotubes with the axial direction facing the anode.

The present inventor has proposed, as a prior application, a method of manufacturing an electron gun which solves the above-mentioned problems of the prior art (Japanese Patent Application No. 11-245033).

The object of the present invention is to further improve the invention of the prior application, whereby carbon nanotubes can be grown locally only on the tops of the protrusions while controlling the growth length, and the generation of dust as impurities. (EN) Provided are a method for growing a carbon nanotube capable of suppressing the above, and a method for manufacturing an electron gun and a probe using the same.

[0020]

A method of growing carbon nanotubes according to one aspect of the present invention comprises a step of forming a protrusion having a top on a surface layer, the protrusion excluding the top and the surface layer. A step of forming a mask layer different from the material for forming the surface layer and the protrusions on the above, a step of contacting the top portion not covered with the mask layer with a catalyst, and containing carbon under heating. A step of decomposing gas, vapor-depositing carbon nanotubes on the top, and projecting the tips of the carbon nanotubes from the top, and a step of vapor-depositing the carbon nanotubes.
And a step of removing the mask layer .

According to one embodiment of the present invention, the area other than the top portion to be brought into contact with the catalyst is covered with the mask layer. The carbon nanotubes can be reliably grown in the region where the catalyst is in contact. The reason is that the catalyst facilitates the formation of nuclei on the top or literally functions as a catalyst during the vapor phase growth of carbon nanotubes. As described above, since the region in contact with the catalyst is limited to the top of the protrusion, the growth length of the carbon nanotube can be controlled by controlling the growth time of the carbon nanotube formed on the top. If other areas (protrusion base and surface layer)
If the growth of other carbon nanotubes or unnecessary carbon agglomerates proceeds in parallel with the top portion in other regions without being masked, it will cause a variation in the growth length of the top carbon nanotubes, and This is because the growth length cannot be controlled accurately.

The process gas used in the vapor phase growth step is preferably a hydrocarbon gas, more preferably one or more selected from methane, ethane and propane . In one aspect of the present invention, a step of removing the mask layer can be performed after the vapor phase growth step of the carbon nanotubes.

Unnecessary carbon lumps are formed on the mask layer during the vapor phase growth process. The unnecessary carbon lumps are easily peeled off and adversely affect as impurities, but the carbon lumps can be removed together with the mask layer.

[0024]

The carbon nanotubes used in the present invention may be either single-walled or multi-walled, but single-walled nanotubes whose tip portion can be reduced in diameter are more preferable.

The surface layer and the protrusions are preferably made of amorphous silicon, polycrystalline silicon, single crystal silicon, or conductive silicon doped with impurities. With these materials, carbon nanotubes can be directly grown. Further, by heat-treating the surface layer and the protrusions, the mask layer can be formed of a silicon compound such as a silicon oxide film or a silicon nitride film. The materials of the surface layer and the protrusions are not limited to those described above, and may be, for example, a metal thin film or a semiconductor.
Further, if the surface layer and the protrusions are the above-mentioned materials, the substrate itself, which is a base material for forming these, may be an insulator such as a glass substrate.

As the material of the mask layer, in addition to the above-mentioned silicon compound, semiconductor, polycrystalline silicon, amorphous silicon, metal or organic molecular film can be used. The mask layer may be made of any material as long as it can prevent the lower layer of the mask layer from coming into contact with the catalyst and can be peeled off later from the lower layer. In addition, when the mask layer is removed after the vapor phase growth process, the mask layer is required to be a material that can withstand the high temperature during the vapor phase growth process. When the mask layer is formed of photoresist, it can be removed by ashing or the like, and when it is formed of an organic molecular film, it can be removed by etching or ashing. When the mask layer is formed of a metal such as tungsten, platinum, titanium, germane, or the like, it can be removed by dry etching or dissolving with an acid.

In one aspect of the present invention, the step of forming the mask layer so as to cover the surface layer and the protrusion, and a coating layer different from the material for forming the mask layer on the mask layer, The protrusion excluding the top portion is formed by a step of leaving the top portion, a step of locally removing the mask layer on the top portion not covered by the coating layer, and a step of removing the coating layer thereafter. The mask layer may be formed to cover the portion and the surface layer.

In this case, the coating layer can be formed of any one of photoresist, organic molecular film, semiconductor, polysilicon, amorphous silicon and metal.

The catalyst may be a solution containing chloride. This solution preferably contains one or more chlorides selected from ferrous chloride, ferric chloride, molybdenum oxide chloride, and silicon chloride. In this case, an alcohol solution is used as the solvent for the solution. be able to. Also,
The solution can include a surfactant.

Another aspect of the present invention is to provide an electron having a sharp emitter formed on a surface layer of a substrate, a grid for controlling electron emission from the emitter, and an anode facing the tip of the emitter. In the method of manufacturing a gun, the emitter is formed by using the above-described carbon nanotube growth method according to one aspect of the present invention.

In the electron gun thus manufactured, the tip of the carbon nanotube directly grown on the protrusion projects from the tip of the protrusion, and the tip of the carbon nanotube is used as an emitter edge, Electrons can be emitted from the tip. Since the carbon nanotubes are formed along the protrusions, the carbon nanotubes can be arranged with their axial direction facing the anode. At this time, even if the axial direction of the carbon nanotube is not necessarily perpendicular to the anode surface, the emitted electrons can reach the anode by the electric field. Since the diameter of the carbon nanotube is as small as 1 to 10 nm, the sharpening of the tip portion is achieved, and the emitter edge can be formed by carbon having a low work function. In addition, since the carbon nanotubes are directly grown on the protrusions, there is no need to attach them,
The length of the carbon nanotube can be optimally set.

A field emission display can be cited as an electronic device using this electron gun. This display has an anode in which a phosphor is formed for each pixel, and an electron gun array configured by disposing one or a plurality of electron guns formed as described above facing each pixel. In the emitter of this field emission display, the tip of the carbon nanotube is used as an emitter edge, whereby the emitter edge is sharpened, and fine processing for that is unnecessary. Therefore, this field emission display can be adapted to a large screen.

As another electronic device using this electron gun,
A scanning electron microscope, an electron beam exposure apparatus, an exposure apparatus, a repair apparatus, etc. can be mentioned.

Still another aspect of the present invention is a method for manufacturing a probe having a cantilever, a protrusion formed on the tip of the cantilever, and a contact protruding from the protrusion, wherein the contact is described above. It is characterized by being formed by using the carbon nanotube growth method according to one embodiment of the present invention.

Examples of electronic equipment using this type of probe include an atomic force microscope, a scanning tunneling microscope, and a scanning probe microscope.

In these electron gun or probe manufacturing methods, the vapor phase growth step is carried out until the tip of the carbon nanotube protrudes from the tip of the protrusion, so that the carbon nanotube having a desired protrusion length is formed on the protrusion. Can be grown directly on. Therefore, this carbon nanotube can be preferably used as an emitter edge of an electron gun and a contact of a probe.

[0038]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of an electron gun to which the method of the present invention is applied will be described below with reference to the drawings.

(Explanation of Principle of Electron Gun of the Present Invention) FIG. 1 is a schematic explanatory view of an electron gun to which the method of the present invention is applied. In FIG. 1, a large number of protrusions, for example, Si cones 12, are formed on the surface of, for example, the conductive silicon layer 10 serving as a cathode. On the conical surface of the Si cone 12, a carbon nanotube 20 serving as an emitter (also called a microcathode) is directly grown and formed,
The tip portion 20A projects further than the top portion 12A of the Si cone 12. A grid (gate) 30 for controlling the amount of electrons emitted from the carbon nanotubes 20 is arranged at a position that does not interfere with the flight path of electrons emitted from the carbon nanotubes 20. Further, an anode (fluorescent plate) 40 is arranged at a position facing the conductive silicon layer 10 with the grid 30 interposed therebetween.

A constant voltage from a constant power source Va is applied to the conductive silicon layer 10 and the anode 40, and a variable voltage from the variable gate voltage source Vg is applied to the conductive silicon layer 10 and the grid (gate) 30. Is applied.

FIG. 1 shows an electron gun which is a cathode element for displaying one pixel of the EFD, and a large number of electron guns having the structure shown in FIG. 1 are formed on the same substrate or divided substrates in correspondence with the phosphor of each pixel. A two-dimensional image forming apparatus as an FED can be configured by forming the matrix shape to form a multi-electron beam source. Note that, as shown in FIG. 1, a plurality of carbon nanotubes 20 may be arranged to face one pixel, or one carbon nanotube 20 may be arranged.

The driving principle of the panel constituting the FED is as follows. Carbon nanotube (emitter) 20
When the voltage necessary for the operation of is set to Ve, a voltage of, for example, -Ve / 2 is applied to the conductive silicon layer (cathode line) 10 and, for example, + Ve is applied to the grid (gate line) 30.
A voltage of / 2 is applied. Only the pixel line in which the potential of the conductive silicon layer (cathode line) 10 becomes −Ve / 2 is selected, and the grid (gate line) 3 is selected.
Due to the + Ve / 2 luminance signal applied to 0, the voltage Ve acts only on the selected field emitter, and the plurality of carbon nanotubes 20 corresponding to one pixel 20
More electrons are emitted. Since only the voltage Ve / 2 is applied to the emitters of the other pixel lines, no electrons are emitted. Further, by controlling the voltage applied to the grid (gate line) 30, the amount of electrons emitted from the carbon nanotube (emitter) 20 is controlled,
It is possible to display a gradation for each pixel on the anode 40.

Here, the carbon nanotube 20 functioning as an emitter is a hollow tube formed by spirally twisting a six-membered ring. The carbon nanotube 20 has a single-layer carbon nanotube having a single twisted structure and double or more double-walled carbon nanotubes. There is a multi-walled carbon nanotube, which has a multi-layered twisted structure. In the present invention, single-walled and multi-walled carbon nanotubes can be adopted, but single-walled carbon nanotubes having a small diameter are preferable.

The diameter of this carbon nanotube 20 is 1
-10 nm, and in the case of single-walled carbon nanotubes, the diameter can be 1-3 nm. Further, although the carbon nanotubes 20 can grow to a length of about 100 nm, shorter ones are superior in that the resistance value can be lowered when used as an emitter. In particular, shortening the length of the protruding portion 20A protruding from the top portion 12A of the Si cone 12 is effective in reducing the resistance value, and the length of the protruding portion 20A is 50 nm or less, preferably 20 nm or less, and further preferably Is preferably 10 nm or less.

As described above, when the carbon nanotube 20 is used as the emitter and the axial tip protruding from the protrusion such as the Si cone 12 is used as the emitter edge, the emitter tip diameter becomes nano-order and the emitter current is increased by sharpening. Alternatively, the driving voltage for obtaining a desired emitter current can be reduced.

(Structural Example of Electron Gun) FIG. 2 shows a structural example showing the electron gun of FIG. 1 more specifically. In FIG. 2, a cathode electrode layer 1 is formed on a substrate, for example, a glass substrate 100.
02 is formed. When forming an FED, the cathode electrode layer 102 can be formed by depositing amorphous silicon, polycrystalline silicon, or the like in a line on the glass substrate 100. This cathode electrode layer 10
2 may be single crystal silicon or conductive silicon doped with impurities. If the multi-electron source used for the FED or the like is not configured, the insulating substrate is not necessary. In this case, the substrate 100 itself can be a single crystal silicon substrate or a silicon substrate doped with impurities.

Further, at least the surface layer of the substrate is not limited to the one formed of silicon, but may be other semiconductor, conductor such as metal.

On the cathode electrode layer 102, a plurality of protrusions, for example, cone shapes 104 are formed. On the cone shape 104, the carbon nanotubes 110 protruding from the top portion 104A of the cone shape 104 are formed, and the electron gun is constituted by this. A resistance layer (for example, amorphous silicon) may be formed on the cathode electrode layer 102, the resistance layer itself may be processed, or the cone shape 104 may be formed on the resistance layer. Further, on the cathode electrode layer 102, an anode electrode can be formed around the cone shape 104 with an insulating layer interposed therebetween.
Is omitted in.

(Manufacturing Method of Electron Gun) FIGS. 3 to 10 show respective steps for manufacturing the structure shown in FIG. The glass substrate 100 is omitted in FIGS. 3 to 10.

FIG. 3 shows a process in which the cathode electrode layer 102 and the cone shape 104 formed on the glass substrate 100 are thermally oxidized to form the silicon oxide film 120. As a method of forming the cone shape 104 on the cathode electrode 102, the CVD method described in Japanese Patent Application No. 11-245033, FIGS. 3A and 3B, or FIGS. 5A and 5B. It is possible to use the etching method described in 1).

This silicon oxide film 120 will later function as a mask layer. The mask layer may be made of another silicon compound such as a silicon nitride film, or may be made of a semiconductor, a metal, an organic molecular film, or the like different from the material for forming the protrusion.

FIGS. 4 to 7 show the top 1 of the cone shape 104.
The step of leaving the silicon oxide film 120 only in the region other than 04A is shown.

In FIG. 4, the photoresist film 130 is formed on the silicon oxide film 120 by, eg, spin coating.
Is applied. FIG. 5 shows a step of removing the upper layer of the photoresist film 130 by, for example, ashing. In this step, the height H of the portion exposed from the photoresist film 130 is controlled by controlling the ashing time, for example.
You can decide 1. FIG. 6 shows a process of removing the portion of the silicon oxide film 120 not covered with the photoresist 120 by etching, using the photoresist film 130 as a mask. By this etching, the silicon oxide film 120 is locally removed only on the top portion 104A of the cone shape 104. FIG. 7 shows a step of removing the photoresist film 130 by, for example, ashing. By performing this step, all regions except the top portion 104A, that is, the cathode electrode layer 102 and the base end 104B of the cone shape 104 are covered with the silicon oxide film (mask layer) 120. The height H2 of the top 104A that is not covered with the mask layer 120 is uniquely determined by the relationship with the height H1 obtained in the step shown in FIG.

FIG. 8 shows a catalyst coating process. In this embodiment, the silicon oxide film (mask layer) 120 and the exposed top 104A are contacted with the catalyst 140.

A solution containing chloride is used as the catalyst 140, and the glass substrate 100 is immersed in this solution. As the chloride, one or two selected from ferrous chloride, ferric chloride, molybdenum oxide chloride, and silicon chloride.
It can be a mixture of more than one species. After this immersion step, the vapor phase growth step of the carbon nanotubes 110 is started. For this purpose, the substrate is placed in a CVD furnace, and a hydrocarbon-based gas such as methane, ethane, or propane is mixed with one gas or a mixed gas of two or more gases.
Supply at a flow rate of about 0 sccm. This hydrocarbon-based gas is decomposed under heating in a CVD furnace at a temperature of, for example, 900 ° to convert the carbon nanotubes 110 into cone shapes 104.
Grow directly on top. FIG. 9 shows a process in which the carbon nanotubes 110 grow on the top 104A.

Here, when the vapor phase growth step is carried out after the immersion in the chloride solution, the carbon nanotubes 11
0 has definitely grown. It is considered that this is because chloride contributes to the formation of nuclei formed in the initial stage of vapor phase growth of carbon nanotubes. Alternatively, it is considered that chloride contributes as a catalyst for promoting the growth of the carbon nanotube 110.

As the solvent for dissolving the chloride,
For example, an alcohol solution such as ethanol can be used. It is preferable to use the alcohol solution as the solvent, because after the chloride is attached to the cone shape 104, the alcohol solution evaporates.

The solution preferably contains a surfactant. By activating the interface of the top 104A,
This is because the growth of the carbon nanotubes 110 is promoted and the adhesion strength thereof is enhanced.

The carbon nanotube 110 has a top portion 10.
A nucleus is first formed on the conical surface of 4A, and it is formed by growing it. Although carbon nanotubes are formed on the entire conical surface of the top portion 104A, eventually one carbon nanotube 110 grows to protrude from the top portion 104A. Then, the growth length of the carbon nanotube 110 can be adjusted by controlling the processing time and the like. As a result, the protrusion length L (see FIG. 9) of the tip portion 110A of the carbon nanotube 110 protruding from the top portion 104A of the cone shape 104 can be appropriately adjusted.

Here, during the vapor phase growth step described above, the carbon lump 150 is formed on the surface of the mask layer 120. However, this carbon ingot 150 can be lifted off by peeling off the silicon oxide film 120, as shown in FIG. The silicon oxide film 120 can be removed, for example, by immersing the substrate 100 in hydrofluoric acid. In addition, originally unnecessary carbon lump
When 0 remains, the carbon lump 150 that has been peeled off later may become impurities or dust and impair the function of the electron gun, but in the present embodiment, such a possibility disappears.

Further, since the growth area of the carbon nanotubes 110 is limited to the top portion 104A of the cone shape 104, the growth time of the carbon nanotubes 110 formed on the top portion 104A can be controlled to control the growth length of the carbon nanotubes 110. Controllability. If regions other than the top 104A are not masked, the growth of other carbon nanotubes or unnecessary carbon agglomerates proceeds in the other regions in parallel with the top 104A. This causes a large variation in the growth length of the carbon nanotubes 110 on the top 104A, and the growth length of the carbon nanotubes 110 on the top 104A cannot be accurately controlled.

(Other Example of Method of Manufacturing Electron Gun) The steps of FIGS. 9 and 10 can be replaced with the steps of FIGS. 11 and 12. That is, as the pre-process of each process of FIGS. 11 and 12, each process shown in FIGS. 3 to 8 can be used as it is.

FIG. 11 shows a step of removing the silicon oxide film 120 as the mask layer after the step of contacting with the catalyst shown in FIG. 8 and before the vapor phase growth step. The reference numeral 140 shown in FIG. 11 emphasizes the catalyst remaining on the cone shape 104. Thereafter, as shown in FIG. 12, the carbon nanotubes 110 are vapor-grown on the top portion 104A of the cone shape 104.

As shown in FIG. 11, if the mask layer 120 is removed before the vapor phase growth step shown in FIG. 12, the mask layer 120 is not exposed to the process temperature at the time of vapor phase growth. Heat resistance is not required for layer 120.

Further, in the vapor phase growth step shown in FIG. 12, a carbon lump 150 is formed on a part of the top portion 104A of the cone shape 104 (the lower end of the top portion 104A), and the carbon lump 150 is formed on the mask layer as shown in FIG. It cannot be removed together with 120 and remains. However, as compared with the case where the mask layer 120 is not contacted and the catalyst is contacted, the formation area of the carbon lump 150 becomes extremely narrow. For this reason, the risk of variation in the growth length of the carbon nanotubes is sufficiently reduced, and the risk of scattering as impurities or dust is also reduced.

(Structural Example of Probe) FIG. 13 schematically shows a probe 200 which is another application of the carbon tube. The probe 200 is used for, for example, an atomic force microscope, and includes a cantilever 210, a protrusion formed at the tip of the cantilever 200, for example, a cone shape 104, and a top portion 104 of the cone shape 104.
The carbon nanotube 110 serving as a contactor protruding from A and contacting the object 220 to be measured is provided.

This probe 200 can be manufactured by using the method shown in FIGS. 3 to 10 or FIGS. 3 to 8, 11 and 12. At this time, the cantilever 210
Will be formed in the surface layer 102 shown in FIGS.

As described above, since the contactor can be manufactured by using the carbon nanotube 110 of the order of several nanometers, it can be used as various measuring probes for measuring minute objects.

The present invention is not limited to the above embodiment, but various modifications can be made within the scope of the gist of the present invention. For example, the protrusions on which the carbon nanotubes are grown are not necessarily cone-shaped (conical), but may be trapezoidal-shaped, columnar-shaped, or the like. The point is that the tip of the carbon nanotube protrudes more than the tip of the protrusion. Just do it. This is because the tip of the carbon nanotube in the axial direction can be used as an emitter edge for emitting electrons or a contact for a probe. When the carbon nanotube is used as the emitter of the electron gun, its axial direction does not necessarily need to be perpendicular to the anode surface. This is because the electrons emitted from the tip of the carbon nanotube by the electric field reach the anode surface. Furthermore, the protrusions on which the carbon nanotubes are grown are not necessarily those formed by processing the surface layer of the substrate, but may be those that utilize the irregularities of the surface layer itself. At this time, the step of forming the protrusions on the surface layer is simultaneously performed by forming the surface layer on the substrate.

Further, the electron gun described above is not limited to the one applied to the image display device such as the FED described above, but may be an electron beam or electron beam emitted from an image recording device, an exposure device, a circuit repair device, an electron microscope, or the like. It can be used as an electron emission source for realizing various functions.

[Brief description of drawings]

FIG. 1 is a principle explanatory view of an electron gun in which a carbon nanotube manufactured according to the present invention is used as an emitter.

2 is a cross-sectional view showing a specific structural example of the electron gun of FIG.

FIG. 3 is a cross-sectional view showing a step of thermally oxidizing the silicon surface.

FIG. 4 is a cross-sectional view showing a photoresist coating process.

FIG. 5 is a cross-sectional view showing a cueing process of the silicon oxide film from which the upper layer of the photoresist has been removed.

FIG. 6 is a cross-sectional view showing a step of removing a silicon oxide film from a cone-shaped top portion.

FIG. 7 is a cross-sectional view showing a step of removing a photoresist film.

FIG. 8 is a cross-sectional view showing a catalyst coating step performed by masking a region of the cone shape excluding the top.

FIG. 9 is a cross-sectional view showing a carbon nanotube growth step performed while leaving the mask layer.

FIG. 10 is a cross-sectional view showing a mask layer removing step performed after the step of FIG. 9;

FIG. 11 is a cross-sectional view showing a mask layer removing step performed instead of the step of FIG. 9;

12 is a cross-sectional view showing a carbon nanotube growth step that is performed after the mask layer removal step of FIG.

FIG. 13 is a schematic explanatory view schematically showing a probe provided with carbon nanotubes manufactured by the present invention.

[Explanation of symbols]

10 cathode 12 Si cone 12A top 20 carbon nanotubes 20A tip 30 grid 40 anode 100 glass substrates 102 cathode electrode layer (surface layer) 104 cone shape 104A top 104B base end 110 carbon nanotubes 110A tip 120 Silicon oxide film (mask layer) 130 photoresist film 140 carbon mass 150 catalyst 200 probes 210 cantilever

Continuation of front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) C01B 31/02 H01J 1/30 JISST file (JOIS) WEB OF SCIENCE

Claims (13)

(57) [Claims] 1. A step of forming a protrusion having a top on a surface layer, and a mask different from the material for forming the surface layer and the protrusion on the protrusion except the top and the surface layer. A step of forming a layer, a step of contacting the top portion not covered with the mask layer with a catalyst, a gas containing carbon is decomposed under heating, and carbon nanotubes are vapor-grown on the top portion. After the step of projecting the tip of the carbon nanotube from the top and the step of vapor-depositing the carbon nanotube,
And a step of removing the mask layer . 2. A protrusion having a top is formed on the surface layer.
And a step on the surface layer except for the top portion,
A mask layer different from the material for forming the surface layer and the protrusions is used.
Forming step and contacting the top not covered by the mask layer with a catalyst
And the step of decomposing the gas containing carbon under heating,
The carbon nanotubes are grown by vapor growth of carbon nanotubes.
Projecting the tip of the tube from the top, and the surface layer and the protrusions are amorphous silicon,
Silicon, single crystal silicon, or impurities
The conductive layer is a conductive silicon layer , and the mask layer is formed by heat treating the surface layer and the protrusions.
Carbon that is a silicon compound formed
How to grow nanotubes. 3. The method for growing carbon nanotubes according to claim 1 , wherein the carbon nanotubes are single-walled nanotubes. 4. The method for growing carbon nanotubes according to claim 1 , wherein the carbon nanotubes are multi-walled nanotubes. 5. A method according to claim 1, 3 or 4, wherein the mask layer is a semiconductor, polycrystalline silicon, growing method of a carbon nanotube, characterized in that any one of amorphous silicon, metal or an organic molecular film. 6. In any one of claims 1 to 5, the mask layer to form over the surface layer and the protrusions, the mask layer is different from the material for forming the mask layer Forming a coating layer, leaving the top portion, a step of locally removing the mask layer on the top portion not covered by the coating layer, and a step of removing the coating layer thereafter, A method of growing carbon nanotubes, comprising forming the mask layer that covers the protrusion except the top and the surface layer. 7. The coating layer according to claim 6 , wherein the coating layer is a photoresist, an organic molecular film, a semiconductor,
A method for producing a carbon nanotube, which is one of polysilicon, amorphous silicon, and metal. 8. The one of claims 1 to 7, wherein the catalyst is a manufacturing method of a carbon nanotube which is a solution containing chloride. 9. The method according to claim 8 , wherein the solution contains at least one chloride selected from ferrous chloride, ferric chloride, molybdenum chloride, and silicon chloride. Method for producing carbon nanotube. 10. The method for producing carbon nanotubes according to claim 9 , wherein the solvent of the solution is an alcohol solution. 11. The method for producing carbon nanotubes according to claim 8 , wherein the solution contains a surfactant. 12. A method of manufacturing an electron gun, comprising: a sharp emitter formed on a surface layer of a substrate; a grid for controlling electron emission from the emitter; and an anode facing the tip of the emitter. an electron gun producing method characterized in that formed using the method of growing the carbon nanotube according to any one of claims 1 to 11 to the emitter. 13. A method of manufacturing a probe having a cantilever, a protrusion formed at a tip of the cantilever, and a contactor protruding from the protrusion, wherein the contactor is one of claims 1 to 11. A method for producing a probe, which is formed by using the method for growing carbon nanotubes described above.