JPH09161659A - Electron emitting element and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stably emit an electron and simplify a manufacturing process. SOLUTION: A pair of electrodes 12, 13 is formed on a substrate at the specified intervals, and an electron emission layer 14 is formed so as to come in contact with the electrodes. The electron emission layer 14 is a thin film layer formed by dispersing iron very fine particles 41 having a particle size of about 10-50nm in a high resistant layer comprising magnesium oxide, and it can be formed in a vapor deposition method or a sputtering method. The distribution density is set so that the distance between the very fine particles 41 becomes about 50nm, and when voltage is applied across the electrodes 12, 13, current flows within the electron emission layer, and an electron emission phenomenon from the surface can be confirmed.

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, and more particularly, to a surface conduction electron-emitting device.

[0002]

2. Description of the Related Art As a kind of flat panel display, FED (Field Emission Display) has been energetically studied. In this FED, a cathode substrate and an anode substrate are opposed to each other, a number of electron-emitting devices are arranged on the cathode substrate, electrons are emitted from the electron-emitting devices toward the anode substrate, and a phosphor layer on the anode substrate is formed. It emits light. The electron-emitting devices formed on the cathode substrate correspond to individual pixels. The electron-emitting devices used so far generally have a sharp projection structure suitable for electron emission. For example, an electron-emitting device made of a conical metal with a sharp tip is widely used. I have.

On the other hand, in recent years, surface conduction electron-emitting devices have been receiving attention. This is an electron-emitting device utilizing a phenomenon in which an electron is emitted when a current flows through a thin film having a small area formed on a substrate in parallel with the film surface.
Such an electron emission phenomenon was described in 1965 in “Radio Engineering Electrophysics (Radio Eng.
Electron. Phys.) Volume 10, 1290-1296 "
Since then, by MI Elinson et al., Various reports have been made to date. Specifically, this surface conduction type electron emission phenomenon has been reported for SnO ₂ (Sb) thin film developed by Erinson et al., Au thin film, ITO thin film, carbon thin film and the like. It is known that such a phenomenon is a peculiar electron emission phenomenon that occurs in a thin film in which a high resistance region is locally present, and usually, a forming process is performed to form a local high resistance region. To be done. For example, Japanese Examined Patent Publication (Kokoku) No. 6-87392 discloses a method of manufacturing an electron-emitting device having a surface conduction type electron-emitting function by heating a conductive thin film containing fine particles with electricity. In this method, a cracking can be locally generated in the conductive thin film by a forming process called electric heating, and the cracked portion functions as a high resistance region.

[0004]

However, it is very difficult to manufacture a device capable of stable electron emission by the manufacturing method which performs the above-mentioned forming treatment.
When a conductive thin film is formed on a substrate and the conductive thin film is subjected to forming treatment such as electric heating, a local crack occurs in the film due to electric breakdown, and this crack portion functions as a high resistance region. Become. Therefore, in order to realize stable electron emission, it is necessary to uniformly generate cracks in the thin film. However, in this forming process, it is difficult to control the location of cracks, the size of the cracks, etc., and in order to realize an element capable of stable electron emission, a high technology is required for this forming process. Will be required.

Further, as described above, the surface conduction electron-emitting device is a device that is expected to be used for a flat panel display such as an FED, and when applied to such a display, many electron-emitting devices are formed on a substrate. It is necessary to arrange these elements in a matrix to obtain stable and uniform electron emission from each element. If elements with unstable operation are mixed, the screen display as a display becomes uneven,
High-quality displays can no longer be realized. Therefore, in application to a display, it is necessary to make the characteristics of the individual electron-emitting devices forming each pixel as uniform as possible so that stable electron emission can be obtained from all the devices. Therefore, in the case of an electron-emitting device used for a display, a higher level of forming process is required.

In order to solve the problem of the forming process, Japanese Patent Publication No. 6-101297 proposes a structure of an electron-emitting device which does not require the forming process. That is, in this publication, fine particles are dispersed on the surface of a first insulating layer, and a second insulating layer is formed on the surface of the first insulating layer to form a structure in which the dispersed surface of the fine particles is sandwiched by insulating layers, and the surface conduction There is disclosed a technique for forming a positive electron-emitting device. However, in this structure, since it is necessary to sandwich the fine particle dispersion surface between the insulating layers, a new problem arises that the manufacturing process becomes complicated.

Therefore, an object of the present invention is to provide an electron-emitting device which can be manufactured by a simple process and can stably emit electrons, and a manufacturing method thereof.

[0008]

[Means for Solving the Problems]

(1) A first aspect of the present invention is an electron emission layer in which fine particles made of a conductive material are dispersed in a layer made of an insulating material,
An electron-emitting device is configured by a pair of electrodes that are in contact with the electron-emitting layer and are arranged at a predetermined distance from each other, and a support substrate that supports the electron-emitting layer and the pair of electrodes.

(2) The second aspect of the present invention is the above-mentioned first aspect.
In the electron-emitting device according to the aspect, ultrafine particles having a diameter of 100 nm or less are used as the respective fine particles forming the electron-emitting layer.

(3) A third aspect of the present invention is the above-mentioned first aspect.
Alternatively, in the method for manufacturing an electron-emitting device according to the second aspect, a conductive material, an insulating material, and a supporting substrate on which an electron-emitting layer is formed are housed in a chamber, and the conductive material and the insulating material are provided. Heat and evaporate, then on the supporting substrate,
The heating conditions of both materials were controlled so that the vapor deposition layer in which the fine particles of the conductive material were dispersed in the layer of the insulating material was formed, and the electron emission layer was formed by the vapor deposition layer. It is a thing.

(4) The fourth aspect of the present invention is the above-mentioned first aspect.
Alternatively, in the method for manufacturing an electron-emitting device according to the second aspect, a conductive material, an insulating material, and a supporting substrate on which an electron-emitting layer is formed are housed in a chamber, and the conductive material and the insulating material are provided. Each target is subjected to sputtering, and the sputtering conditions for both materials are controlled so that a sputtering forming layer in which fine particles made of a conductive material are dispersed in a layer made of an insulating material is obtained on the supporting substrate. The electron emission layer is formed by a sputtering formation layer.

(5) The fifth aspect of the present invention relates to the above-described fourth aspect.
In the method for manufacturing an electron-emitting device according to the aspect 1, the supporting substrate is rotated during sputtering so that the composition ratio of the conductive material and the insulating material in the sputtering formation layer is uniform on the substrate. Is.

(6) The sixth aspect of the present invention is the above-mentioned first aspect.
Alternatively, in the method for manufacturing an electron-emitting device according to the second aspect, a composite target of a conductive material and an insulating material having a target surface having an area ratio corresponding to a composition ratio of an electron-emitting layer to be formed is prepared, A support substrate for forming an electron emission layer and a composite target are housed in a chamber, sputtering is performed on the composite target to obtain a sputtering formation layer on the support substrate, and the sputtering formation layer forms the electron emission layer. It was done like this.

(7) A seventh aspect of the present invention is the above-mentioned third aspect.
In the method for manufacturing an electron-emitting device according to the sixth aspect, the layer formed on the supporting substrate by vapor deposition or sputtering is heat-treated to form conductive fine particles having a larger particle size.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on an embodiment shown in the drawings.

§1. The structure of the conventional electron-emitting device and
Operation First, the structure and operation principle of a conventional general surface conduction electron-emitting device will be described. FIG. 1 is a cross-sectional view showing the structure of a conventional surface conduction electron-emitting device 10 and a counter substrate 20. In this example, the electron-emitting device 10
Is formed by forming electrodes 12 and 13 on a glass substrate 11 and further forming an electron emission layer 14 thereon. The electron emission layer 14 functions as a cathode electrode, and for example, SnO ₂ , In ₂ O ₃ , Pb is used.
Any material, such as a metal oxide such as O, a metal such as Au and Ag, carbon, and various semiconductors, may be used as long as the material has a known surface conduction electron emission phenomenon. On the other hand, the counter substrate 20 is formed by forming a transparent electrode 22 and a phosphor layer 23 on a glass substrate 21. The transparent electrode 22 is made of, for example, a material such as ITO and functions as an anode electrode.

FIG. 2 is a top view of the components formed on the glass substrate 11 in the electron-emitting device 10 shown in FIG. 1, and the cross section taken along the section line 1-1 in this figure is shown in FIG. It will be. It is clearly shown that the electrodes 12 and 13 are opposed to each other with a predetermined interval, and the electron emission layer 14 is formed therebetween.

Now, let us consider a phenomenon that occurs when wiring is provided to each part as shown in FIG. According to this wiring, the electrode 13 is grounded, and a negative voltage is applied to the electrode 12 from the power supply 31. The cathode / anode voltage is also applied between the electron-emitting device 10 and the counter substrate 20 by the power source 32. In the state shown in FIG. 1, however, the switch 33 is open, so that the voltage is not applied. I haven't been. Now, when a voltage is applied to both sides of the electron emission layer 14 by the electrodes 12 and 13, electron emission as indicated by an arrow in the drawing occurs on the film surface portion of the electron emission layer 14. This is a phenomenon known as surface conduction electron emission.

Here, the switch 33 is closed and the cathode /
When the voltage between the anodes is applied, the electrons emitted to the surface of the electron emission layer 14 fly to the counter substrate 20 on the anode side, as shown in FIG. The collision of electrons toward each other causes the phosphor layer 23 to emit fluorescence. Here, for convenience of explanation, only the components for one pixel are shown.
By arranging components for pixels in a matrix in a matrix, a flat panel display in which pixels are arranged on a two-dimensional plane can be realized. In such a flat panel display, it is general that the switch 33 is kept closed and the voltage applied from the power source 31 is adjusted for each pixel to control the light emitting state of each pixel. More specifically, the amount of electrons flying to the counter substrate 20 side can be controlled by adjusting the value of the voltage applied to the electron emission layer 14 and the application time.

In order to form an electron emission layer having such electron emission characteristics, conventionally, a forming treatment has been performed on a conductive thin film. That is, as shown in the side sectional view of FIG. 4, a pair of electrodes 12, 13 is formed on the glass substrate 11.
After forming the conductive thin film 14Z, both electrodes 1
A relatively large current If for forming is supplied from a power source 34 between the second and the third electrodes 13, and the conductive thin film 14 is formed by Joule heat.
The electron emission layer 14 is formed by locally destroying, deforming or degrading Z to generate an electrically high resistance region (specifically, a crack of about 0.5 μm to 5 μm).
However, in such a forming process, it is difficult to form the electron emission layer 14 capable of stable electron emission because it is not possible to accurately control the generation location and size of the crack. It is as follows.

§2. The structure and structure of the electron-emitting device of the present invention
The operation of the electron-emitting device according to the present invention is the same as in the surface-conduction electron-emitting device as shown in FIG. 1, except that the electron-emitting layer 14 is an electron-emitting device in which fine particles made of a conductive material are dispersed in a layer made of an insulating material. It is composed of a release layer. FIG. 5 is an enlarged cross-sectional view for explaining the basic structure of this electron emission layer. Here, ultrafine particles of iron (Fe) are used as the fine particles 41 made of a conductive material, and a magnesium oxide (MgO) layer 42 is used as a layer made of an insulating material. In general, the term "ultrafine particles" has a diameter of 100n.
It is used for fine particles of m or less, and in the present embodiment, as the fine particles 41, ultrafine iron particles having a diameter of about 10 to 50 nm are used.

As described above, the inventor of the present application has provided the high resistance layer 42 made of an insulating material with the fine particles 4 made of a conductive material.
It was found that if a layer in which 1 is dispersed is formed on a supporting substrate, this layer as a whole functions as an electron emitting layer. That is, as shown in FIG. 5, the insulating material (Mg
The conductive fine particles (F
In the structure in which e) is dispersed, when a predetermined applied voltage V1 is applied between the electrodes 12 and 13, a current flows through a large number of dispersed ultrafine particles 41, and the surface of the electron emission layer 14 is The electron emission phenomenon can be seen from. Such a phenomenon is observed when the diameter and the dispersion density of the conductive fine particles 41 are kept under predetermined conditions. That is, as shown in FIG. 6, the particle diameter of the conductive fine particles 41 in the high resistance layer 42 is D
1. If D2 is the distance from the closest other adjacent fine particles,
Such electron emission phenomenon occurs when D1 and D2 take values in a predetermined range. According to an experiment conducted by the inventor of the present application, the upper limit value of the particle diameter D1 is considered to be about 100 nm, and the present invention can be realized by using the conductive fine particles having the particle diameter D1 of 100 nm or less. On the other hand, the condition regarding the distance D2 from the adjacent fine particles depends on the diameter and shape of the particle, and therefore the numerical condition cannot be unconditionally determined, but it is certain that there is a certain numerical range.
That is, if the distance D2 becomes too small, the entire electron emission layer 14 functions as a mere conductive layer,
The electron emission phenomenon does not occur, and conversely, if the distance D2 becomes too large, electron transfer between adjacent particles does not occur, and the electron emission layer 14 as a whole functions as an insulating layer. It will not occur. Although the critical condition regarding the distance D2 or the particle distribution density for causing the electron emission phenomenon has not been determined at this time, according to the experiment, if D1 = D2 is generally set, efficient electron emission is possible. . In this embodiment, D1 = D2 = about 10 to 50 nm. According to the manufacturing method described later, the diameter and the dispersion density of the conductive fine particles 41 can be freely controlled.

No detailed theoretical consideration has been given to the reason why the electron emission phenomenon occurs in such a structure at this stage. However, the inventor of the present application believes that in such a state in which conductive ultrafine particles having a particle size of 100 nm or less are scattered in the high resistance layer, an environment in which electron emission easily occurs due to the following reasons. ing. That is,
It is generally known that a discharge phenomenon such as corona discharge occurs from a sharp tip. It is not difficult to imagine that the conductive ultrafine particles having a particle diameter of 100 nm or less will perform the same function as this sharp tip. Therefore, it is considered that if such fine conductive ultrafine particles are scattered in the high resistance layer, electron emission may occur in the same manner as discharge occurs from the needle tip in vacuum. In particular, in FIG. 5, if a negative voltage is applied to the electrode 12 side, it is considered that excess charges are generated in the region of the electron emission layer 14 in the vicinity of the electrodes 12 due to the application of the negative voltage. It seems to contribute to electron emission. In addition, according to the manufacturing method described later, a state in which the conductive ultrafine particles are scattered in the high resistance layer as shown in FIG. 5 can be immediately obtained, and thus fine cracks are generated in the layer as in the conventional case. It is no longer necessary and the conventional forming process is no longer necessary.

According to the present invention, very stable electron emission can be obtained from the surface of the electron emission layer 14. Electron emission layer 1
As shown in FIG. 5, 4 is a layer in which conductive fine particles 41 are dispersed in a high resistance layer 42. Of course, when the individual fine particles are viewed microscopically, the particle size D1 and the shape are different, and the distance D2 between adjacent fine particles is also different. However, when viewed as a macroscopic view of the electron emission layer 14 as a whole, the particle size and distribution state of each ultrafine particle can be regarded as uniform, and very stable electron emission can be obtained. Further, for example, when manufacturing a display device that displays one pixel by using this one electron emission layer 14, a large number of independent electron emission layers 1 are formed on the support substrate.
4 is formed, but from a macroscopic point of view, the particle size and distribution state of the ultrafine particles in each electron emission layer 14 are almost the same, and the display characteristics between pixels are also uniform. Therefore, it is possible to realize a high-quality display device in which display characteristics between pixels are uniform.

In the above embodiment, ultrafine particles of iron (Fe) are used as fine particles made of a conductive material, and magnesium oxide (MgO) layer is used as a layer made of an insulating material. Is not limited to these, and if an electrically conductive material is used as the fine particles and an insulating material is used as the high resistance layer for dispersing the fine particles, the electron emission phenomenon of the present invention can be obtained. Is possible. For example, as the material for the conductive fine particles, in addition to Fe, Mg, Al, Si, Ti, V, C
r, Mn, Co, Ni, Cu, Zn, Nb, Mo, P
d, Ag, In, Sn, Ta, W, Ir, Pt, Au,
Metals such as Pb and their alloys, SnO ₂ , In
A metal compound such as ₂ O ₃ , PbO, carbon, or a semiconductor can be used. As a material for the high resistance layer, in addition to MgO, Al ₂ O ₃ , SiO ₂ , CaO, Y
It is also possible to use an insulating material such as ₂ O ₃ , ZrO ₂ , or SiN. Alternatively, as the material for the high resistance layer,
An organic material capable of vapor deposition or sputtering such as polyimide may be used.

§3. Another implementation of the electron-emitting device of the present invention
Form The electron-emitting device according to the present invention is not limited to the structure as shown in FIG. 1, and the electron-emitting device in which fine particles made of a conductive material are dispersed in a thin film layer made of an insulating material is formed on a supporting substrate. Any structure may be used as long as it is a structure in which a layer and a pair of electrodes that are in contact with the electron emission layer and are arranged at a predetermined distance from each other are formed. For example, when the present invention is applied to the electron-emitting device having the conventional structure shown in FIG. 1, the electron-emitting layer 14 is formed on the electron-emitting layer 14 as shown in FIG.
It may be a thin film layer having a fine particle dispersion structure shown in. Hereinafter, the structures of some other embodiments will be exemplified.

In the structure shown in FIG. 1 or 5, an electrode 12, an electron emission layer 14 and an electrode 13 are arranged side by side on a support substrate 11. On the other hand, in the structure shown in FIG. 7, the structures are arranged vertically. That is, first, as shown in FIG. 7A, a three-layer structure in which a lower electrode layer 52, an intermediate insulating layer 53, and an upper electrode layer 54 are laminated on a supporting substrate 51 (not shown) is formed. Then, an electron emission layer 55 is formed on the side surface end portion as shown in FIG. 7B. Here, the electron emission layer 55 is a thin film layer in which conductive fine particles are dispersed in a high resistance layer, as in the example shown in FIG. The electron-emitting device 50 can be formed also with such a structure.

That is, as shown in the side sectional view of FIG. 8, a three-layer structure in which a lower electrode layer 52, an intermediate insulating layer 53, and an upper electrode layer 54 are laminated on a glass substrate 51 is formed, Further, an electron-emitting device 50 having an electron-emitting layer 55 formed on the side surface end is prepared, and the counter substrate 2 is provided above the electron-emitting device 50.
0 is placed. The opposing substrate 20 is formed by forming a transparent electrode 22 and a phosphor layer 23 on a glass substrate 21.
Here, as shown in FIG. 8, wiring is provided to each part. With this wiring, the electrode layer 52 is grounded, and a negative voltage is applied to the electrode layer 54 from the power supply 31. In addition, the electron-emitting device 5
The cathode / anode voltage is also applied between 0 and the counter substrate 20 by the power supply 32, but in the state shown in FIG. 8, the voltage is not applied because the switch 33 is open. When a voltage is applied to both sides of the electron emission layer 55 by the electrode layers 52 and 54, electron emission as indicated by an arrow in the figure occurs at the film surface portion of the electron emission layer 55.

Here, the switch 33 is closed and the cathode /
When the voltage between the anodes is applied, the electrons emitted to the surface of the electron emission layer 55 will fly to the counter substrate 20 on the anode side, as shown in FIG. The collision of electrons toward each other causes the phosphor layer 23 to emit fluorescence. Here, for convenience of explanation, only the components for one pixel are shown.
By arranging components for pixels in a matrix in a matrix, a flat panel display in which pixels are arranged on a two-dimensional plane can be realized. In such a flat panel display, it is general that the switch 33 is kept closed and the voltage applied from the power source 31 is adjusted for each pixel to control the light emitting state of each pixel. More specifically, the amount of electrons flying to the counter substrate 20 side can be controlled by adjusting the value of the voltage applied to the electron emission layer 55 and the application time.

The structure shown in FIG. 10 is the structure shown in FIG. 7 with steps. That is, first, as shown in FIG. 10A, a lower electrode layer 62, an intermediate insulating layer 63, and an upper electrode layer 64 are formed on a supporting substrate 61 (not shown).
To form a three-layer structure. This three-layer structure is
The side part has a step structure. Therefore, the electron emission layer 65 is formed in this step structure portion as shown in FIG. 10 (b). Here, the electron emission layer 65 is a layer in which conductive fine particles are dispersed in the high resistance layer, as in the example shown in FIG. The electron-emitting device 60 can also be formed with such a structure.

In short, the feature of the present invention resides in that fine particles made of a conductive material are dispersed in a high resistance layer made of an insulating material to form an electron emission layer. The electrodes may be contacted in any form to form an electron-emitting device.

§4. Method for manufacturing electron emission layer according to the present invention
Method As described above, the feature of the present invention is that an electron emission layer in which conductive particles are dispersed in a high resistance layer is formed.
Such an electron emission layer can be manufactured by a very simple manufacturing process. For example, a conductive material, an insulating material, and a supporting substrate are housed in a chamber, the conductive material and the insulating material are heated and evaporated, and an electron emission layer can be obtained as a vapor deposition layer over the supporting substrate. it can. In this case, the heating conditions of both materials are controlled so that the vapor deposition layer in which fine particles made of a conductive material are dispersed in the high resistance layer made of an insulating material is formed. Specifically, the temperature control is performed so as to suppress the evaporation amount of the conductive material as compared with the evaporation amount of the insulating material.

It is also possible to use a sputtering method instead of the vapor deposition method. That is, it suffices to perform sputtering with the conductive material and the insulating material housed in the chamber as targets to obtain a sputtering formation layer on the supporting substrate. In this case, the sputtering conditions of both materials are controlled so that the high-resistivity layer made of an insulating material can obtain a sputtering formation layer in which fine particles made of a conductive material are dispersed. Specifically, control is performed so as to suppress the amount of conductive material sputtered as compared with the amount of insulating material sputtered. The supporting substrate is preferably rotated during sputtering so that the composition ratio of the conductive material and the insulating material in the sputtering formation layer is uniform on the substrate.

When the sputtering method is used, it is possible to use a composite target of a conductive material and an insulating material. That is, if a composite target of a conductive material and an insulative material having a target surface having an area ratio corresponding to the composition ratio of the electron emission layer to be formed is prepared, a desired target can be obtained only by performing sputtering on the composite target. It becomes possible to form the electron emission layer.

By conducting heat treatment on the layer formed on the supporting substrate by vapor deposition or sputtering, it becomes possible to form conductive fine particles having a larger particle size. As described above, the particle size and distribution density of the conductive fine particles are parameters that influence the electron emission efficiency. Therefore, when the electron emission layer having the optimum particle size and distribution density cannot be formed by vapor deposition or sputtering, the particle size and distribution density are adjusted by applying heat to this layer. be able to. That is, when heat is applied, a phenomenon in which a plurality of adjacent particles are fused to form larger particles occurs, so that the particle size can be increased and the number of particles can be reduced.

[0036]

EXAMPLES A specific method of manufacturing an electron-emitting device according to the present invention will be described below with reference to some examples. This manufacturing process uses a film forming technique called a so-called vapor deposition method or sputtering method. According to this method, it is possible to form the high resistance layer in which the conductive fine particles are dispersed on the substrate in a short time and by a very simple process. Actually,
When applied to a display device, etc., a patterning process that leaves the electron-emitting layer only in the necessary places by etching after forming the electron-emitting layer on one surface of the supporting substrate by the vapor deposition method or the sputtering method described below. Alternatively, a predetermined mask may be arranged on the supporting substrate at the time of vapor deposition or sputtering to selectively form the electron emission layer only on a necessary portion.

(1) First Manufacturing Method (Evaporation Method) First, as shown in FIG. 11, iron (Fe) as a conductive material and magnesium oxide (MgO) as an insulating material are prepared in a chamber. Then, the support substrate 70 on which the electron emission layer is formed is arranged. Then, each material is heated at a predetermined temperature to be evaporated, and the evaporated material is supported by the supporting substrate 70.
Deposit on top. In this embodiment, vapor deposition by heating using an electron beam (EB vapor deposition) is performed, but the material may be heated by any method. As shown in the structure of FIG. 5, the electron emission layer formed on the support substrate 70 is
It is necessary that fine particles of iron are dispersed in the layer of magnesium oxide. Therefore, the evaporation amount of each material (that is, the heating temperature of each material) must be controlled appropriately. In this example, for iron, 0.
Evaporation is performed under the condition that the vapor deposition film is formed at a rate of 5 nm / sec, and magnesium oxide is vaporized under the condition that the vapor deposition film is formed at a rate of 10 nm / sec (in other words, Iron: magnesium oxide is evaporated at a ratio of 1:20). Thus, the vapor deposition layer obtained,
That is, the composition ratio of the electron emission layer can be appropriately adjusted by changing the vapor deposition rate of each material, and this composition ratio affects the resistance value of the entire electron emission layer.

As a result of vapor deposition under such conditions, a high-resistivity layer made of magnesium oxide having a thickness of 100 nm is formed on the support substrate 70, and a grain size of 1 to 5 nm is formed therein.
A vapor deposition layer was obtained in which ultrafine particles of iron having an average particle size (average particle size of about 3 nm) were dispersed. When this vapor-deposited layer was used as it was as an electron emission layer, very efficient electron emission was not obtained. This is probably because the ultrafine iron particles are too small. Therefore, this deposited layer was left in a temperature environment of 300 ° C. for about 1 hour to be heat-treated. As a result, a plurality of adjacent ultrafine particles were fused and the average particle diameter of the iron ultrafine particles was expanded to about 15 nm. As a result of using the vapor-deposited layer after the heat treatment as an electron emission layer, efficient electron emission was obtained from the surface.

In order to form a vapor deposition layer on the supporting substrate 70 in which the composition ratio of the conductive material and the insulating material is uniform, the distance L1 between both materials shown in FIG. It is preferable that the material of the evaporation source is not biased and that the distance L2 between the evaporation source and the supporting substrate 70 is as large as possible.

(2) Second Manufacturing Method (Sputtering Method) In the above vapor deposition method, each material is heated and evaporated, but sputtering can be performed instead. That is, if the iron material and the magnesium oxide material shown in FIG. 11 are used as targets to perform sputtering, a sputtering formation layer can be obtained on the support substrate 70. Also in this case, if the sputtering conditions for each material are controlled separately, a sputtering forming layer having a desired composition ratio can be obtained. Note that in order to obtain the sputtering formation layer having a uniform composition ratio of the conductive material and the insulating material on the supporting substrate 70, the sputtering is performed while rotating the supporting substrate 70 in a plane parallel to the substrate surface. It is preferable to do so.

When performing the sputtering method,
It is also possible to use a composite target of a conductive material and an insulating material. That is, as shown in FIG. 12, if a composite target made of iron and magnesium oxide is prepared, an electron emission layer having a desired composition ratio can be obtained on the supporting substrate 70 only by performing unitary sputtering on the composite target. Is possible. In this case, the composition ratio of the conductive material and the insulating material forming the formed electron emission layer is determined by the composition ratio of the target surface of the prepared composite target. In the case of this embodiment, a composite target in which iron chips are embedded in a bulk of magnesium oxide is used, and the area ratio of magnesium oxide and iron on the target surface to be sputtered is, for example, 50: 1. By using such a composite target, it becomes possible to obtain an electron emission layer having a composition ratio of both of 20: 1 on the supporting substrate 70 (since the sputter rate varies depending on the material, The composition ratio of the composite target will be determined in consideration of the sputter rate of each material).

Of course, it is possible to increase the particle size of the iron fine particles by subjecting the layer formed by such a sputtering method to the heat treatment described above.

[0043]

As described above, according to the present invention, since the electron emission layer is formed by dispersing the conductive fine particles in the high resistance layer, stable electron emission is possible, and the production is also improved. It becomes possible to realize an electron-emitting device having a simple process.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a structure of a general surface conduction type electron-emitting device 10 and a counter substrate 20 which have been conventionally proposed.

2 is a top view of components formed on a glass substrate 11 in the electron-emitting device 10 shown in FIG. 1, and a cross section taken along a cutting line 1-1 in this figure is shown in FIG.

3 is a cross-sectional view showing a state where electrons are being emitted from an electron-emitting device 10 shown in FIG.

4 is an electron emission layer 14 of the electron emission device 10 shown in FIG.
FIG. 6 is a cross-sectional view showing a method of forming a by a forming process.

FIG. 5 is an enlarged cross-sectional view for explaining a basic structure of an electron emitting layer in the electron emitting device according to the present invention.

6 is a diagram showing a distribution state of particles in the electron emission layer shown in FIG.

FIG. 7 is an electron-emitting device 5 according to another embodiment of the present invention.
It is a perspective view which shows the concrete structure of 0.

8 is an electron-emitting device 50 and a counter substrate 2 shown in FIG.
It is sectional drawing which shows the structure of 0.

9 is a cross-sectional view showing a state where electrons are being emitted from the electron-emitting device 50 shown in FIG.

FIG. 10 is a perspective view showing a specific structure of an electron-emitting device 60 according to another embodiment of the present invention.

FIG. 11 is a conceptual diagram showing a first method of manufacturing an electron-emitting device according to the present invention.

FIG. 12 is a conceptual diagram showing a second manufacturing method of the electron-emitting device according to the present invention.

[Explanation of symbols]

 10 ... Electron emitting element 11 ... Glass substrate 12 ... Electrode 13 ... Electrode 14 ... Electron emitting layer 14Z ... Conductive thin film 20 ... Counter substrate 21 ... Glass substrate 22 ... Transparent electrode 23 ... Phosphor layer 31 ... Power source 32 ... Power source 33 ... Switch 34 ... Power source 41 ... Conductive fine particles 42 ... High resistance layer 50 ... Electron emitting element 51 ... Support substrate 52 ... Lower electrode layer 53 ... Intermediate insulating layer 54 ... Upper electrode layer 55 ... Electron emitting layer 60 ... Electron emitting element 61 ... Support substrate 62 ... Lower electrode layer 63 ... Intermediate insulating layer 64 ... Upper electrode layer 65 ... Electron emission layer 70 ... Support substrate D1 ... Particle size of conductive particles D2 ... Distance between conductive particles I1 ... Diode current I2 ... Emission Current If ... Forming current V1 ... Applied voltage V2 ... Anode voltage

Claims (7)

[Claims] 1. An electron emitting layer in which fine particles made of a conductive material are dispersed in a layer made of an insulating material, a pair of electrodes which are in contact with the electron emitting layer and are spaced apart from each other by a predetermined distance, and the electrons. An electron-emitting device comprising: an emission layer and a support substrate that supports the pair of electrodes. 2. The electron-emitting device according to claim 1, wherein each of the fine particles forming the electron-emitting layer has a diameter of 100 n.
An electron-emitting device characterized by using ultrafine particles of m or less. 3. The method for manufacturing an electron-emitting device according to claim 1, wherein the chamber contains a conductive material, an insulating material, and a support substrate on which an electron-emitting layer is formed, and the conductive material is used. The material and the insulating material are heated to evaporate, and a vapor deposition layer in which fine particles made of the conductive material are dispersed in a layer made of the insulating material is formed on the support substrate. Each heating condition of the material is controlled,
A method of manufacturing an electron-emitting device, comprising forming an electron-emitting layer by the vapor deposition layer. 4. The method for manufacturing an electron-emitting device according to claim 1, wherein a conductive material, an insulating material, and a supporting substrate on which an electron-emitting layer is formed are housed in a chamber, and the conductive material is used. Sputtering is performed using a material and the insulating material as targets, so that a sputtering formation layer in which fine particles made of the conductive material are dispersed in the layer made of the insulating material is obtained on the support substrate. A method for manufacturing an electron-emitting device, wherein the electron-emitting layer is formed by the sputtering forming layer by controlling the sputtering conditions of both materials. 5. The method for manufacturing an electron-emitting device according to claim 4, wherein the supporting substrate is formed during sputtering so that the composition ratio of the conductive material and the insulating material in the sputtering formation layer is uniform on the substrate. A method for manufacturing an electron-emitting device, which comprises rotating the electron-emitting device. 6. The method of manufacturing an electron-emitting device according to claim 1, wherein a composite of a conductive material and an insulating material having a target surface having an area ratio corresponding to a composition ratio of an electron-emitting layer to be formed. A target is prepared, a support substrate for forming the electron emission layer and the composite target are housed in a chamber, sputtering is performed on the composite target, and a sputtering formation layer is obtained on the support substrate. A method for manufacturing an electron-emitting device, comprising forming an electron-emitting layer with a forming layer. 7. The method of manufacturing an electron-emitting device according to claim 3, wherein a layer formed on the supporting substrate by vapor deposition or sputtering is heat-treated to form conductive fine particles having a larger particle size. A method of manufacturing an electron-emitting device, comprising: