JP2001126609A - Electron emission device and fluorescent display - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electron emission device with high performance that may be fabricated at low cost and driven by low voltage. SOLUTION: An electron emission device comprises a glass substrate 100, cathode 101, resistor layer 102, insulating layer 103, and a gate electrode 104. On a metal layer 106 with high central portion in the opening 108, there is formed a carbon nano tube 107 by plasma CVD. A voltage is applied to the cathode 101 and gate electrode 104 to make the carbon nano tube generate electrons.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electron-emitting device that emits electrons and a fluorescent display using the same.

[0002]

2. Description of the Related Art Conventionally, a field electron emission element which emits electrons by the action of an electric field is superior to an electron source utilizing thermal energy (thermoelectron emission element) in that it can save energy and have a longer life. Due to the large number of points, electron-emitting devices such as Spindt-type electron-emitting devices are being researched and developed for applications such as display devices. At present, semiconductors such as Si and metals such as W and Mo are known as materials for such electron-emitting devices. Since the field emission device needs to improve the electron emission efficiency, it concentrates the electric field at its tip.
The semiconductor or metal is formed in a cone shape or the like, and the tip is formed sharp, and this is used as an emitter for electron emission.

[0003]

However, in the case of the Spindt-type vapor deposition emitter, it is not easy to form the tip of an electron-emitting material such as Mo uniformly and sharply, so that the manufacturing apparatus becomes expensive and the manufacturing cost becomes low. There was a problem that it was difficult to do. If the emitter and the gate electrode are formed as close as possible to submicron or less, the electron emission ability can be obtained with low voltage driving and high efficiency, but a short circuit may occur between the emitter and the gate electrode. In order to form a high-efficiency electron-emitting device at a low voltage, there has been a problem that accuracy control during manufacturing is not easy.

An object of the present invention is to provide an electron-emitting device which can be manufactured at low cost, can be driven at a low voltage, and can easily obtain a highly efficient electron-emitting capability. Another object of the present invention is to provide a fluorescent light-emitting display device that can be manufactured at low cost, can be driven at a low voltage, and can perform light-emitting display with high efficiency.

[0005]

According to the present invention, there is provided an electron-emitting device having an insulating substrate, a first electrode provided on the insulating substrate, and a distance above the first electrode. The second
And a metal layer disposed between the first electrode and the second electrode and having a central portion formed thicker than a peripheral portion; and a carbon nanotube and a carbon nanofiber formed on the metal layer. And an emitter made of a carbon material containing at least one of them. When a voltage is applied between the first electrode and the second electrode, electrons are emitted from the emitter formed on the metal layer.

Here, the semiconductor device comprises: an insulating layer provided between the first electrode and the second electrode; and an opening formed in the second electrode and the insulating layer. The metal layer may be configured to be disposed in the opening. A resistive layer disposed between the first electrode and the insulating layer and formed so as to be exposed from the opening; and the metal layer is disposed so as to be in contact with the resistive layer. And the emitter may be formed on the metal layer.

[0007] The carbon nanotubes and carbon nanofibers may be formed on the metal layer so as to be oriented in a predetermined direction with respect to the insulating substrate. Furthermore, at least one of a carbon nanotube and a carbon nanofiber may be formed at a central portion and a peripheral portion of the metal layer. The metal layer may be formed of a material containing at least one of Fe, Ni, Co, and Y.

Further, in the fluorescent light emitting display according to the present invention, the electron-emitting device and the anode electrode on which the phosphor is attached are disposed in a vacuum-tight container, and the electrons emitted from the electron-emitting device are emitted by the electron-emitting device. In a fluorescent light-emitting display device that performs light-emitting display by colliding with a phosphor, as the electron-emitting device,
A feature is that any one of the above-described electron-emitting devices is used. Thereby, efficient light-emitting display is performed at a low voltage.

[0009]

FIG. 1 is a side sectional view showing a manufacturing process of an electron-emitting device according to a first embodiment of the present invention.
3 is a side sectional view of the electron-emitting device according to the first embodiment of the present invention, and FIG. 3 is a partially enlarged side sectional view of FIG. Hereinafter, a first embodiment of the present invention will be described with reference to FIGS.

A method of manufacturing an electron-emitting device according to the first embodiment will be described. Referring to FIG. 1, first, a cathode electrode 101 (for example, Nb) as a first electrode is formed on a glass substrate 100 which is an insulating substrate. An electrode comprising
Next, a resistance layer 102 (for example, a layer made of amorphous Si) is formed. Here, as described later, the resistance layer 102 is for stabilizing the amount of emitted electrons and preventing overcurrent when the gate electrode 104 and the carbon nanotube 107 are short-circuited. Therefore, when stabilization can be realized by the resistance of the emitter material itself, or when stabilization can be achieved by simultaneously obtaining electron emission from a plurality of emitters, the resistance layer 102 can be omitted.

Next, an insulating layer 103 (for example, a layer made of SiO ₂ ) and a gate electrode 104 (for example, an electrode made of Nb) as a second electrode are formed by lamination. Next, patterning is performed by a method such as dry etching or wet etching to form the insulating layer 103 and the gate electrode 1.
An opening 108 on the order of microns is formed in the substrate 04 to expose the resistance layer 102. The opening 108 is formed in a cylindrical concave shape. At this time, the cathode electrode 101 and the gate electrode 104 are arranged in a matrix.

Next, a lift-off film 105 made of Al is formed on the gate electrode 104 by oblique deposition or the like.
Is formed in a reduced state. Then spatter,
By performing EB evaporation, resistance heating evaporation, arc discharge evaporation, or the like, the substrate 100
A metal layer 106 is formed on the resistance layer 102 in the opening 108 in a direction perpendicular to the opening so that the thickness of the metal layer 106 at the center is about several tens nm. At this time, the metal layer 106
The central part is formed thicker than the peripheral part. In addition, as a material of the metal layer 106, an iron-based metal (for example, Fe, N
i, Co), Y, or a material containing at least one of them is suitable for growing carbon nanotubes and carbon nanofibers, as described later.

In this state, a linear carbon nanotube 107 is formed on the surface of the metal layer 106. Metal layer 106
As a method of forming the carbon nanotubes 107 thereon, various methods such as a CVD (Chemical Vapor Depotision) method or a PVD (Physical Vapor Depotision) method can be used, and a plasma CVD method and an arc plasma method are more suitable. . In the case of CVD, low-molecular-weight hydrocarbons such as methane, ethane, acetylene, and ethylene are used as raw material gases and are simply thermally decomposed in an electric furnace or by a hot filament, or are subjected to DC plasma or RF (Radio Frequency). ) Plasma, magnetron plasma, ECR (Electron Cyclotron Resonanc)
e; electron cyclotron resonance) to form a linear carbon nanotube 107 on the surface of the metal layer 106. When plasma is used, radical molecules having a lower molecular weight than those obtained by thermal decomposition are generated, and the reactivity can be improved and controlled.

If necessary, a glass substrate 100,
In a state where the cathode electrode 101, the resistive layer 102, the insulating layer 103, the gate electrode 104, and the lift-off film 105 are stacked, heat treatment is performed by laser irradiation, lamp heating, or substrate resistance heating in a temperature range of 500 ° C. or less. Thereby, the conditions for forming the carbon nanotubes 107 are controlled. As a raw material of the carbon nanotube, the C
In the case of VD, a low molecular hydrocarbon gas was used, but ferrocene (Fe (C ₅ H ₅ ) ₂ ) and other metallocenes (M (C ₅ H ₅ ) ₂ ; M = V, Cr, Fe, Co, N
(i, Ru, Os) may be used.

At this time, the carbon nanotube 107
Is formed not only on the metal layer 106 but also on the lift-off film 105. Thereafter, the lift-off film 105 is peeled off to complete the electron-emitting device having the emitter 201 including the metal layer 106 and the carbon nanotube 107 as shown in FIG.

FIG. 3 shows a partially enlarged side sectional view of FIG. 2, in which an emitter 201 is formed on a resistance layer 102 in a cylindrical opening 108 surrounded by a gate electrode 104 and an insulating layer 103. . As for the thin metal layer 106, a metal layer 106 having a center portion thicker than a peripheral portion is formed, and a predetermined ratio (for example, at least 1% or more) of the carbon nanotubes 107 is formed on the metal layer 106.
It is formed so as to be oriented in a predetermined direction with respect to 00 (for example, a direction perpendicular to the glass substrate 100 or a direction having a predetermined angle). Further, a gate electrode 104 is formed over the insulating layer 103.

Since the metal layer 106 has a thick central portion and a thin peripheral portion, a thick and long carbon nanotube 301 is formed at the central portion of the metal layer 106, and a thin and short carbon nanotube 302 is formed at the peripheral portion. . That is, the carbon nanotubes 107 are formed in the central part and the peripheral part of the metal layer 106, and the form thereof is formed in a so-called tree shape so as to become shorter toward the periphery of the metal layer 106. The carbon nanotube 107 is not formed near the insulating layer 103. In order to form the carbon nanotubes at a predetermined angle with respect to the glass substrate 100, an electric field having a predetermined strength and a predetermined direction may be applied to the glass substrate 100 when the carbon nanotubes are generated.

As described above, if a predetermined distance between the metal layer 106 and the gate electrode 104 is secured, the metal layer 1
Since the possibility that the carbon nanotubes 302 in the area around 06 short-circuits with the gate electrode 104 is reduced, the production becomes easy. In addition, the carbon nanotube 301 at the center of the metal layer 106 can be formed close to the gate electrode 104, and the carbon nanotube 301 mainly contributes to the field emission. It becomes possible.

In the electron-emitting device formed as described above, when a voltage is applied between the cathode electrode 101 and the gate electrode 104, electrons are emitted from the carbon nanotube 107 forming the emitter 201.
At this time, as described above, electrons are mainly emitted from the carbon nanotube 301 at the center of the metal layer 106. Therefore, it is possible to form an electron emission array having relatively uniform directionality, uniformity and energy width of emitted electrons.

Further, by forming a plurality of emitters 201 and selectively driving a cathode electrode 101 and a gate electrode 104 arranged in a matrix by applying a voltage, electrons are emitted from a desired emitter 201. It can be driven as described above, and can be used as an electron-emitting device of various electronic devices including a display device. In the embodiment, since the resistance layer 102 is used, the emitter 201 (specifically, the metal layer 10
6) is formed directly on the resistive layer 102. However, when it is not particularly necessary to stabilize electron emission and prevent overcurrent when preventing short circuit, the resistive layer 102 can be omitted. In other words, the metal layer 106 is formed in contact with the cathode electrode 101.

Next, a fluorescent display is formed by using the electron-emitting device configured as described above. FIG.
FIG. 2 is a partially cutaway side view of the fluorescent light emitting display according to the embodiment of the present invention, which is an example of the fluorescent light emitting display using the electron-emitting device having the above-described configuration. In FIG. 4, the same parts as those in FIGS. 1 to 3 are denoted by the same reference numerals. FIG.
In the fluorescent light-emitting display device, a glass substrate 100 as an insulating substrate formed of borosilicate glass and constituting a rear substrate, and a glass substrate as an insulating substrate constituting a translucent front substrate formed of borosilicate glass 401,
Further, a vacuum airtight container constituted by a seal glass 404 for sealing around the glass substrates 100 and 401 is provided.

As described above, the glass substrate 100
, A cathode electrode 101, a resistance layer 102, an insulating layer 103, and a gate electrode 104 are laminated and adhered.
Further, on the inner surface of the resistive layer 102, an emitter 201 formed continuously with the resistive layer 102 is laminated and deposited in the opening 108 between the gate electrodes 104. On the other hand, on the inner surface of the glass substrate 401, an anode electrode 402 and a phosphor 403 attached to the anode electrode 402 are stacked and arranged.

In the case of a fluorescent light-emitting display of a type for displaying characters, graphics, etc., the cathode electrode 101,
The anode electrode 402 and the gate electrode 104 are formed in a pattern suitable for the purpose, such as forming them in a matrix shape, or forming a specific electrode in a solid shape and forming other electrodes in a matrix shape. Also, in the case of a fluorescent light emitting display used as a light emitting element for a pixel of a large screen display device, the pattern of each electrode is appropriately selected and formed.

In the fluorescent light-emitting display device having the above-described structure, the fluorescent material 403 emits light by supplying a driving signal of a predetermined voltage to the cathode electrode 101, the gate electrode 104, and the anode electrode 402, and the formation pattern and the driving signal of each electrode are formed. Accordingly, light-emitting display such as characters and graphics or light-emitting display as a light-emitting element can be performed. At this time, among the carbon nanotubes exposed on the surface of the emitter 201, an electric field is concentrated mainly on the carbon nanotube formed at the central portion of the metal layer, and thus electrons are mainly emitted from the carbon nanotube. This enables low-voltage driving and high-luminance, high-quality light-emitting display.

FIG. 5 is a partially enlarged side sectional view of an electron-emitting device according to a second embodiment of the present invention, and FIGS.
The same reference numerals are given to the same parts as. In FIG.
On a glass substrate 100 which is an insulating substrate, a cathode electrode 101 (for example, an electrode made of Al) as a first electrode, an insulating layer 103 (for example, a layer made of glass),
The gate electrode 104 (for example, an electrode made of Ag) is laminated. An opening 108 is formed between the insulating layer 103 and the gate electrode 104. In the opening 108 on the cathode electrode 101, the metal layer 10 made of the above-described metal (for example, Fe, Ni, Co, Y) is formed.
An emitter 201 in which a film 6 and a tree-shaped carbon nanotube 107 are laminated is formed.

The metal layer 106 is formed so that its central portion is thicker than its peripheral portion. A thick and long carbon nanotube 301 is formed at the central portion of the metal layer 106, and the peripheral portion of the metal layer 106 is formed at the peripheral portion. Thin and short carbon nanotubes 302 are formed. That is, as in the first embodiment, the carbon nanotubes 107 are formed so as to become shorter as they go closer to the periphery of the metal layer 106. In particular, the carbon nanotubes 107 are formed around the vicinity of the insulating layer 103. Not formed.

A method for manufacturing an electron-emitting device according to the second embodiment will be described.
An Al thin film is formed by sputtering or the like, and is patterned into a predetermined pattern by a photolithography method to form a cathode electrode 1.
01 is formed. From above, an insulating glass is printed in a predetermined pattern by screen printing to form the insulating layer 103 and the opening 108. For example, about 3
Printing is performed to a film thickness of 0 μm, and an opening 108 having a diameter of about 50 μm is formed.

Next, a gate electrode 104 is formed on the insulating layer 103 by screen printing of an Ag paste. Next, using an ink in which Fe—Ni fine particles (for example, a particle diameter is about 80 nm) is dispersed, the opening 1 is formed by an inkjet method.
08, a metal layer 106 made of Fe—Ni particles is formed. At this time, the central part of the metal layer 106 is formed thicker than the peripheral part due to surface tension.

Thereafter, carbon nanotubes 107 are formed on the metal layer 106 by a method similar to that of the first embodiment using a plasma CVD method, an arc plasma method, or the like. Glass substrate 1
A bundle of tree-shaped carbon nanotubes oriented in a predetermined direction (vertical direction or predetermined angle direction) with respect to 00 is formed. That is, a thick and long carbon nanotube 301 is formed at the center of the metal layer 106, and a thin and short carbon nanotube 302 is formed toward the periphery. As a result, the cathode electrode 101, the insulating layer 103, and the gate electrode 104 were formed on the glass substrate 100, and the emitter 201 was provided on the cathode electrode in the opening 108 between the insulating layer and the gate electrode. The electron-emitting device is completed.

Also in the second embodiment, the first
The same effect as that of the embodiment can be obtained. still,
As the material of the metal layer 106, similarly to the first embodiment, an iron-based metal (for example, Fe, Ni, Co) or Y having a catalytic function for generating carbon nanotubes, or Y among these, Materials containing at least one are suitable. Further, similarly to the first embodiment, a resistance layer (not shown) may be formed between the cathode electrode 101 and the metal layer 106 to stabilize electron emission and prevent overcurrent. Good.

In each of the above embodiments, the carbon material forming the emitter 201 has been described using carbon nanotubes as an example. However, carbon nanofibers can be produced by the same process as carbon nanotubes. Like the nanotubes, the present invention can be applied to the electron-emitting device and the fluorescent display.
That is, in each of the above embodiments, it is possible to use a carbon material containing at least one of the carbon nanotube 107 and the carbon nanofiber as the material of the emitter 201.

As described above, the electron-emitting device according to each of the above embodiments includes the glass substrate 100 and the glass substrate 1.
Cathode electrode 101 (first electrode)
A gate electrode 104 (second electrode) spaced apart above the cathode electrode 101;
A metal layer 106 disposed between the metal layer 106 and the gate electrode 104 and having a central portion thicker than the peripheral portion, and carbon containing at least one of a carbon nanotube 107 and a carbon nanofiber formed on the metal layer 106. And an emitter 201 made of a material. Therefore, even when the emitter 201 and the gate electrode 104 are formed close to each other, the possibility that a short circuit occurs between the emitter 201 and the gate electrode 104 can be reduced.
Manufacturing is facilitated, the manufacturing yield is improved, manufacturing can be performed at low cost, and high-efficiency electron emission can be performed at low voltage.

Here, the electron-emitting device according to each of the above embodiments has an insulating layer 103 provided between the cathode electrode 101 and the gate electrode 104, and an opening formed in the gate electrode 104 and the insulating layer 103. And a unit 108,
The metal layer 106 is provided in the opening 108. Further, a resistance layer 102 is provided between the cathode electrode 101 and the insulating layer 103 and formed so as to be exposed from the opening 108. The metal layer 106 is provided so as to be in contact with the resistance layer 102. And an emitter 201 made of a carbon material containing at least one of the carbon nanotubes 107 and the carbon nanofibers on the metal layer 106.
Are formed. Therefore, an electron-emitting device having a large number of thin and small emitters 201 can be easily configured, and the presence of the resistance layer 102 can prevent the occurrence of overcurrent even when the emitter 201 and the gate electrode 104 are short-circuited. Characteristics can be made uniform and stable.

The carbon nanotubes 107 and the carbon nanofibers are formed in a state of being oriented in a predetermined direction (vertical direction or a direction inclined at a predetermined angle) with respect to the horizontal direction of the glass substrate 100, so that an electric field is applied to the tip thereof. Since concentration occurs, efficient electron emission can be performed at a low voltage. In addition, at least one of the carbon nanotube 107 and the carbon nanofiber is formed in the peripheral portion and the central portion of the metal layer 106, and is not formed in the vicinity of the insulating layer 103, so that the emitter 201 and the gate are formed. The occurrence of a short circuit between the electrodes 104 can be prevented.

In particular, by forming the carbon nanotubes 302 and carbon nanofibers formed in the peripheral portion shorter than the carbon nanotubes 301 and carbon nanofibers formed in the central portion, the emitter 20
1 and the gate electrode 104 can be more effectively prevented, and the carbon nanotube 30
1 and the carbon nanofibers can efficiently emit electrons. The carbon nanotube 10
7 and carbon nanofibers can be formed on the metal layer 106 by a heat generation method, a hot filament CVD method, a plasma CVD method, or an arc plasma method. As a result, the carbon nanotubes 107 and the carbon nanofibers are formed on the metal layer 106 efficiently and inexpensively.

Further, by using a catalyst metal for forming carbon nanotubes or carbon nanofibers, particularly Fe, Ni, Co, Y or a material containing at least one of these as a material of the metal layer 106, the efficiency is improved. The carbon nanotubes 107 and the carbon nanofibers can be produced well, and an inexpensive and highly efficient electron-emitting device can be formed.

The cathode electrode 101 and the gate electrode 1
By arranging the cathode electrodes 101 and the gate electrodes 10 in a matrix, it is possible to form electron-emitting devices suitable for various matrix-driven image display devices.
4. By variously setting the shape and arrangement of the emitter 201, it becomes possible to configure an electron-emitting device for displaying characters and fixed patterns, or for a large-screen pixel.

Further, the electron-emitting device and the anode 402 on which the phosphor 403 is attached are disposed in a vacuum-tight container, and electrons emitted from the electron-emitting device are emitted from the phosphor 40.
In the fluorescent light-emitting display device that emits light by projecting the light onto the electron-emitting device 3, by using the above-described electron-emitting device as the electron-emitting device, low-voltage driving becomes possible, and high brightness and high quality are achieved. Light-emitting display can be obtained.

[0039]

FIG. 6 is a diagram showing the electron emission characteristics of an electron-emitting device according to an embodiment of the present invention.
The gate electrode voltage Vg (V), and the vertical axis represents an emission current Ia (arbitrary unit: AU (Ar) corresponding to the amount of emitted electrons
bitrary Unit)). In FIG. 6, a curve A is a characteristic of the electron-emitting device having the configuration according to the first embodiment, a curve B is a characteristic of the electron-emitting device having the configuration according to the second embodiment, and a curve C is a conventional one. 3 shows the characteristics of the Spindt-type electron-emitting device.

As is clear from FIG. 6, the electron-emitting device having the structure according to the second embodiment can emit electrons at a lower voltage than the Spindt-type electron-emitting device, and has a large electron emission amount. can get. Further, the electron-emitting device having the structure according to the first embodiment can emit electrons at a lower voltage than the electron-emitting device having the structure according to the second embodiment, and has a large electron emission amount. .

[0041]

According to the present invention, it can be manufactured at low cost and
It is possible to provide a highly efficient electron-emitting device that can be driven at a low voltage. Further, according to the present invention, it is possible to provide a fluorescent light-emitting display device which can be manufactured at low cost, can be driven at a low voltage, and can perform light-emitting display with high efficiency.

[Brief description of the drawings]

FIG. 1 is a side sectional view showing a manufacturing process of an electron-emitting device according to a first embodiment of the present invention.

FIG. 2 is a side sectional view of the electron-emitting device according to the first embodiment of the present invention.

FIG. 3 is a partially enlarged side sectional view of the electron-emitting device according to the first embodiment of the present invention.

FIG. 4 is a partially cutaway side view of the fluorescent light emitting display according to the embodiment of the present invention.

FIG. 5 is a partially enlarged side sectional view of an electron-emitting device according to a second embodiment of the present invention.

FIG. 6 is an electron emission characteristic diagram of the electron emission device according to the example of the present invention.

[Explanation of symbols]

100, 401: Glass substrate as an insulating substrate constituting a vacuum-tight container 101: Cathode electrode as a first electrode 102: Resistive layer 103: Insulating layer 104: Second electrode Gate electrode 105: Lift-off film 106: Metal layer 107, 301, 302: Carbon nanotube 108: Opening 402: Anode electrode 403: Phosphor 404: Vacuum tightness Seal glass that constitutes the container

Claims (7)

[Claims] An insulating substrate; a first electrode disposed on the insulating substrate; a second electrode disposed above and separated from the first electrode; and the first electrode. And a metal layer disposed between the second electrode and a central portion formed to be thicker than the peripheral portion, and a carbon material formed on the metal layer and containing at least one of a carbon nanotube and a carbon nanofiber. And an emitter comprising: 2. An electronic device comprising: an insulating layer disposed between the first electrode and the second electrode; and an opening formed in the second electrode and the insulating layer. The electron-emitting device according to claim 1, wherein a metal layer is provided in the opening. A resistive layer disposed between the first electrode and the insulating layer and formed so as to be exposed from the opening, wherein the metal layer is in contact with the resistive layer. 3. The electron-emitting device according to claim 2, wherein the emitter is formed on the metal layer. 4. The electron-emitting device according to claim 1, wherein the carbon nanotubes and the carbon nanofibers are oriented in a predetermined direction with respect to the insulating substrate. 5. The electron according to claim 1, wherein at least one of a carbon nanotube and a carbon nanofiber is formed in a central portion and a peripheral portion of the metal layer. Emission element. 6. The electron emission device according to claim 1, wherein the metal layer is formed of a material containing at least one of Fe, Ni, Co, and Y. element. 7. A light-emitting display by disposing an electron-emitting device and an anode electrode on which a phosphor is attached in a vacuum-tight container, and causing electrons emitted from the electron-emitting device to strike the phosphor. 7. A fluorescent display device according to claim 1, wherein the electron-emitting device according to claim 1 is used as the electron-emitting device.