JP2009016281A - Field-emission type electron emission device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electron emission device, which is produced with fewer processes than a conventional electron emission device, capable of uniformly emitting an electron per unit area. <P>SOLUTION: In a field-emission type electron emission device made of the metal oxide, a projected shape made of metal oxide with a length of more than three micrometers exists at a density of 5 to 100,000 pieces per an area of 1×1 square millimeter on the surface of the metal oxide. When an average length of the sum of optional 100 sets of projected shapes is χ and its standard deviation is σ, an average length becomes χ≥5 μm. And, when a maximum length of the projected shape having the length of χ+σ/2 is L<SB>max</SB>and a minimum length is L<SB>min</SB>, a relationship of these lengths becomes 1≥L<SB>min</SB>/L<SB>max</SB>≥1/3. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a field emission type electron-emitting device made of a metal oxide having a specific protrusion structure and a method for manufacturing the same. The electron-emitting device of the present invention can be effectively used as an electron-emitting device for a light source such as an image / video display device or illumination, and an electron-emitting device for a micro vacuum tube.

As the electron-emitting device, a hot cathode device such as a cathode ray tube has been conventionally used. However, the hot cathode device has a problem of low energy efficiency because electrons are emitted by thermal energy. Therefore, in recent years, the demand for field emission type electron-emitting devices that do not require thermal energy for electron emission is increasing.
An example of a field emission electron emission device is an arrayed field emission electron emission device having the structure shown in FIG. In this cold cathode device, a large number of cone-shaped electron emission sources 31 are arranged in parallel on a high conductivity silicon substrate 8 with gaps therebetween. Each electron emission source 31 is disposed in a cavity separated by an insulating layer 30, and an extraction electrode 4 having a hole 14 for exposing the tip of each electron emission source 31 is provided on the insulating layer 30. In this field emission type electron-emitting device, by applying a high voltage between the extraction electrode 4 and the electron emission source 31, a strong electric field is generated at the tip of the electron emission source 31, and electrons are generated from the tip of the electron emission source 31. Released.

  This field emission type electron-emitting device is called a Spindt type and is manufactured, for example, as follows. First, a silicon oxide film to be the insulating layer 30 is formed on the high conductivity silicon substrate 8, and a molybdenum film to be the extraction electrode 4 is formed thereon. Next, a hole pattern is formed on the molybdenum film, and the molybdenum film and the silicon oxide film are etched using this pattern. Thereby, holes corresponding to the positions of the respective electron-emitting devices are formed in the molybdenum film and the silicon oxide film. Next, an aluminum sacrificial layer is obliquely deposited in the hole portion of the molybdenum film, and then molybdenum is deposited in a cone shape in the hole of the silicon oxide film. Next, the aluminum sacrificial layer is removed by etching.

However, since the above-mentioned Spindt-type field emission electron-emitting device requires many processes as described here, there is a problem that it requires a large facility and a lot of energy for production.
In view of the present situation, the present inventors have proposed a metal oxide structure having a protrusion shape by using the method disclosed in Patent Document 1, that is, an organometallic pyrolysis method (hereinafter referred to as “MOCVD method”). did. Furthermore, it has been proposed to obtain a field emission type electron-emitting device as shown in Patent Documents 2 and 3 using this metal oxide structure.
Patent Document 4 discloses a structure using a needle-like crystal as a field emission type electron-emitting device.

  However, in the electron-emitting device using the structure shown in Patent Documents 1 to 4, electrons are emitted by generating an electric field at the tip of the electron-emitting device, and as a result, the phosphor is excited to emit light. Although described, there is no disclosure about which portion of the portion where the phosphor is present is excited. When the part where the phosphor exists is only partially excited to emit light, for example, a non-uniform light emission can be obtained as a light source such as a light source such as an image / video display device or illumination and a micro vacuum tube. was there. In addition, if a higher electric field is generated in the electron-emitting device to cause the entire phosphor portion to emit light, the light emission efficiency may be reduced, or the portion of the electron-emitting device that emits a large current may be accelerated. There were also challenges. In either case, there is a problem that it is difficult to obtain a suitable light-emitting element for many applications.

Republished No. 99/57345 JP 2000-276999 A JP 2002-274819 A Japanese Patent No. 2793702

The present invention is a further development of the above prior art.
In the present invention, a field emission type electron-emitting device made of a metal oxide having a specific protrusion structure solves the above-described problem, and is manufactured with fewer steps than a conventional electron-emitting device, and emits electrons uniformly per unit area. An electron-emitting device is provided.

As a result of intensive studies on a field emission type electron-emitting device in which uniform field electron emission occurs with high efficiency and low power consumption, the present inventor has found that a metal having a projection structure having a specific structure and shape with a specific distribution. The present inventors have found that an oxide structure solves the above problems and have completed the present invention.
That is, the present invention is as follows.
1. Arbitrary protrusions made of metal oxide having a density of 5 to 100,000 per 1 mm × 1 mm area on the metal oxide surface, and having a protrusion shape made of a metal oxide having a length of 3 μm When the sum average length of 100 shapes is χ and the standard deviation is σ, the maximum length of the protrusion shape having a length of χ ≧ 5 μm and χ + σ / 2 or more is L _max , and the minimum length is L _min If it, 1 ≧ L _min / L _max is made of a metal oxide, wherein ≧ 1 / a 3 field emission type electron-emitting device.

2. In the protrusion shape made of a metal oxide having a length χ + σ / 2 or more, the number of protrusion shapes having a length (L _min + L _max ) / 2 or more is 1 / of the number of protrusion shapes having a length χ + σ / 2 or more. 3. The above 1. 2. The field emission type electron-emitting device described in 1.
3. 1. The above-mentioned 1. characterized in that the sum-average circle-converted diameter of the projection-shaped cross section made of a metal oxide having a length of 3 μm is 0.01 to 100 μm. Or 2. 2. The field emission type electron-emitting device described in 1.
4). 1. The ratio of the length of the projection-shaped cross section made of a metal oxide having a length exceeding 3 μm to the circle-converted diameter is 1 or more. ~ 3. The field emission type electron-emitting device according to any one of the above.
5). 1. The curvature radius of the protrusion-shaped tip portion made of a metal oxide having a length exceeding 3 μm is 100 nm or less. ~ 4. The field emission type electron-emitting device according to any one of the above. 6). The above-mentioned 1., wherein the central axes of the protrusions are substantially parallel. ~ 5. The field emission type electron-emitting device according to any one of the above.

7). 1. The metal oxide is a metal oxide single crystal. ~ 6. The field emission type electron-emitting device according to any one of the above.
8). 1 above, wherein the metal in the metal oxide contains at least one of Mg, Al, Si, Ti, Mn, Fe, Ni, Cu, Zn, Ga, Y, Zr, In, Sn, and Ba . ~ 7. The field emission type electron-emitting device according to any one of the above.
9. 1. At least the tip of the protrusion shape is coated with a material having a work function smaller than the work function of the metal oxide constituting the protrusion shape. ~ 8. The field emission type electron-emitting device according to any one of the above.
10. The substance having a work function smaller than the work function of the metal oxide constituting the protrusion shape is at least one film of amorphous microcrystalline carbon nitride, microcrystalline carbon nitride, amorphous carbon, microcrystalline carbon, and diamond. The above-mentioned 9. 2. The field emission type electron-emitting device described in 1.
11. The above-described 1. is characterized in that the protrusions are fixed with at least one material selected from an organic substance, an inorganic substance, and a metal. -10. The field emission type electron-emitting device according to any one of the above.

12 Li, Be, Na, Mg, Al, Si, K, Ca, Ti, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, As, Sr, Y, Zr, Nb, Pd, Cd, Β-diketone, ethylenediamine, piperidine, piperazine, cyclohexanediamine, tetraazacyclotetradecane, ethylenediaminetetra of at least one metal selected from the metal group consisting of In, Sn, Sb, Ba, W, Pb, Bi, Th Choose from acetic acid, ethylenebis (guanide), ethylenebis (salicylamine), tetraethylene glycol, aminoethanol, glycine, triglycine, naphthyridine, phenanthroline, pentanediamine, pyridine, salicylaldehyde, salicylideneamine, porphyrin, thiourea A metal with coordinated ligand A metal selected from the group consisting of alkoxide, carbonyl, carboxyl, alkyl, alkenyl, phenyl or alkylphenyl, olefin, aryl, cyclobutadiene and other conjugated diene groups, Among organometallic compounds in which one or more selected from a dienyl group such as a pentadienyl group, a triene group, an arene group, and a trienyl group such as a cycloheptatrienyl group are bonded, and halides thereof A step (1) of heating a metal compound selected from 1 to a metal compound gas having a concentration of 1% by weight or more;
A step (2) of blowing the metal compound gas onto a substrate in air to form a metal oxide having a protrusion shape;
The temperature of the interface that releases the metal compound gas into the air is T ₁ , and the temperature at the half of the distance between the end of the pipe and the substrate at the center of the cross section of the opening interface is T ₁ <T ₂ <T ₃ , where T ₂ and substrate temperature are T ₃ . ~ 11. A method for manufacturing a field emission type electron-emitting device according to any one of the above.

13. 12. The water pressure in the pipe containing the metal compound gas is less than 200 Pa. A manufacturing method of the field emission type electron-emitting device described in 1.
14 12. The metal compound according to the above 12, wherein the metal compound is at least one of a metal complex containing a β-diketone as a ligand, a metal alkoxide, and an alkyl metal. Or 13. A manufacturing method of the field emission type electron-emitting device described in 1.
15. Above 1. ~ 11. A light-emitting device comprising the field emission type electron-emitting device according to any one of the above.

  The field emission electron emission device of the present invention is easy to manufacture, and the field emission electron emission device of the present invention can emit electrons uniformly with low power consumption per unit area.

Hereinafter, embodiments of the present invention will be described in detail.
The field emission electron-emitting device of the present invention has a protrusion shape in which protrusions made of a metal oxide having a length exceeding 3 μm exist at a density of 5 to 100,000 per 1 mm × 1 mm area on the metal oxide surface. It consists of a metal oxide.
Since the protrusion shape having a length of 3 μm or less is fine, in the use as a field emission type electron-emitting device, the effect as the protrusion shape is not exhibited regardless of the existence density of the protrusion shape. In addition, when the preferred method of the present invention for producing the metal oxide having the protrusion shape is used, a lot of minute protrusion shapes having a length of 3 μm or less may be formed. In many cases, a minute protrusion shape having a length of 3 μm or less is formed extremely densely, and in a use as a field emission type electron-emitting device, it functions only as a plane. Therefore, in the present invention, a protrusion shape exceeding 3 μm in length is defined as a structural factor.

The length of the protrusion shape of the present invention indicates the length from the surface of the substrate to the apex of the protrusion shape.
The density of protrusions made of a metal oxide having a length of more than 3 μm is characterized by 5 to 100,000 per 1 mm × 1 mm area on the metal oxide surface, preferably 50 to 70000, and more preferably Is 250 to 40,000. When the density of protrusions made of a metal oxide having a length of more than 3 μm is less than 5 per 1 mm × 1 mm area on the metal oxide surface, the light emitting element only emits light uniformly in a planar shape from the portion where the electron-emitting device exists. It is difficult to obtain field electron emission. If the density of protrusions made of a metal oxide having a length of more than 3 μm exceeds 100,000 per 1 mm × 1 mm area on the metal oxide surface, it becomes difficult to generate an electric field at the tip of each protrusion. It is difficult to obtain uniform field electron emission.
The population range for calculating the density of the protrusion shape made of metal oxide exceeding 3 μm in length is from the number of protrusion shapes consisting of metal oxide exceeding 3 μm in length in 100 μm square, or from metal oxide exceeding 3 μm in length. The larger one of the square ranges having an arbitrary length including ten protrusion shapes is used.

The field emission electron-emitting device of the present invention is made of a metal oxide having χ ≧ 5 μm, where χ is a sum average length of 100 arbitrary protrusion shapes made of a metal oxide having a length exceeding 3 μm. It is also a feature, preferably χ ≧ 7 μm, more preferably χ ≧ 10 μm.
When the sum average length of the protrusion shape is less than 5 μm, it is difficult to generate an electric field at the tip of each protrusion shape, and it is difficult to obtain field electron emission. Further, even when field electron emission is obtained, it is difficult to obtain field electron emission sufficient to uniformly emit light in a planar shape from the portion where the electron-emitting device exists. The upper limit of the sum average length varies depending on the application to be used and is not particularly limited. From the viewpoint of the durability of the protrusion shape and the time for forming the protrusion shape, χ ≦ 1000 μm is preferable. More preferably, χ ≦ 500 μm, and particularly preferably χ ≦ 100 μm.

The field emission type electron-emitting device of the present invention has a length of χ + σ / 2 or more, where χ is a sum average length of 100 arbitrary protrusions made of a metal oxide having a length exceeding 3 μm and σ is a standard deviation. It is also characterized by being made of a metal oxide satisfying 1 ≧ L _min / L _max ≧ 1/3, where L _max is the maximum length of the protrusion shape having L and L _min is the minimum length. In the case of L _min / L _max <1/3, field electron emission occurs only around the protrusion shape of L _max , and field electron emission sufficient to uniformly emit light in a planar shape can be obtained from the portion where the electron-emitting device exists. Have difficulty. It is obvious that the upper limit of L _min / L _max is 1.

  The field emission electron-emitting device according to the present invention has the property of an electronic device, and at least a part of the surface of the field emission electron-emitting device has conductivity. Even if the metal oxide having a projection shape itself has conductivity, an insulating metal oxide having a projection shape is coated and / or coated with a conductive material, or a conductive material having a projection shape. Either a metal oxide coated and / or coated with a conductive material may be used. Of course, as long as a part of the surface of the field emission electron-emitting device has conductivity, conductivity may be imparted to the metal oxide having a protruding shape by any of the conventionally known methods.

The electrical conductivity of the present invention preferably has a specific resistance value of 10 Ω · cm or less. Even if the specific resistance exceeds 10 Ω · cm, there is no problem as long as electron emission by field emission occurs. Whether electron emission is due to field emission is determined by using, for example, the electric field (E) generated in the electron-emitting device and the current value (I) per unit area emitted by the electron-emitting device, 1 / E on the horizontal axis, and ln (I A two-dimensional plot (Fowler-Nordheim plot) with / E ² ) as the vertical axis is performed, and it can be confirmed whether or not there is a straight line with a downward slope.

The field emission electron-emitting device of the present invention has a length of χ + σ / 2 or more, where χ is a sum average length of 100 arbitrary protrusion shapes made of a metal oxide having a length exceeding 3 μm, and σ is a standard deviation. Metal oxide characterized in that, in a certain protrusion shape, the number of protrusion shapes having a length (L _min + L _max ) / 2 or more is one third or more of the number of protrusion shapes having a length χ + σ / 2 or more It is also preferable because it is possible to obtain field electron emission that only emits light uniformly in a planar shape from the portion where the electron-emitting device exists. More preferably, in the protrusion shape having a length χ + σ / 2 or more, the number of protrusion shapes having a length (L _min + L _max ) / 2 or more is ½ or more of the number of protrusion shapes having a length χ + σ / 2 or more. It is.

When a preferred method for producing a metal oxide having a protrusion shape constituting the field emission electron-emitting device of the present invention is used, the length distribution between protrusion shapes having a length χ + σ / 2 or more is close to L _max . May indicate the maximum frequency. Also in this case, it is preferable that field electron emission can be obtained only by emitting light uniformly in a planar shape from a portion where the electron-emitting device exists.
In the projection shape having a length χ + σ / 2 or more, when the number of projection shapes having a length (L _min + L _max ) / 2 or more is less than 1/3 of the number of projection shapes having a length χ + σ / 2 or more, It is not preferable because there may be a case where field electron emission sufficient to emit light uniformly in a planar shape cannot be obtained from a portion where the electron-emitting device exists.

  This is due to the following reason. That is, in field electron emission, the electric field generated in the electron-emitting device is the larger value of the potential difference between the anode or extraction electrode and the cathode electrode divided by the distance between the anode or extraction electrode and the tip of the electron-emitting device that is the cathode electrode. Can be estimated with a value. Therefore, when the potential difference between the anode or the extraction electrode and the cathode electrode is constant, the longer the length of the projection shape, the shorter the distance between the anode or the extraction electrode and the tip of the electron-emitting device, so that a higher electric field is generated. It will be. As a result, electrons are likely to be preferentially emitted from the projection shape having a longer length, and field electron emission sufficient to uniformly emit light in a planar shape from a portion where the electron-emitting device exists may not be obtained.

In the field emission type electron-emitting device of the present invention, it is preferable that the sum-average circle-converted diameter of the protrusion-shaped cross section made of a metal oxide having a length exceeding 3 μm is 0.01 to 100 μm.
The protrusion-shaped cross section of the present invention refers to a cross section having the maximum diameter when the protrusion shape is observed from a plane perpendicular to the normal direction of the protrusion shape. The circle-converted diameter is represented by a value that is twice the square root of the value obtained by dividing the area by a conventionally known method such as image analysis and dividing the obtained area by the circumference ratio π.
As a population for calculating the sum-average circle-converted diameter, any one of 100 protrusions made of a metal oxide having a length of 3 μm in a 100 μm square or a metal oxide having a length of 3 μm or more is used. Use the larger one.
The ratio of the length of the cross section to the circle equivalent diameter (aspect ratio) is preferably 1 or more, more preferably 5 or more, and particularly preferably 10 or more. As the aspect ratio is higher, an effect of generating an electric field at the tip of the protrusion shape appears. The upper limit of the aspect ratio is appropriately determined from the viewpoint of the durability of the protrusion shape and the time for forming the protrusion shape.

A sharpened tip is preferably used as a field emission electron-emitting device, and is preferably sharpened. Specifically, the radius of curvature is preferably 100 nm or less, and more preferably 40 nm or less. Here, the radius of curvature is a radius of curvature calculated by approximating the apex portion of the protrusion-shaped convex tip portion to a quadratic curve within a predetermined range. Hereinafter, the radius of curvature will be described using FIG. 4 as an example in which the base is cylindrical and the tip is conical.
FIG. 4A is a perspective view of a protrusion shape. In the protrusion shape 13, the apex C of the cone forming the distal end portion 13b coincides with the central axis O of the cone forming the base portion 13a. FIG. 4B is a diagram showing a surface obtained by cutting the protrusion shape 13 along a plane along the central axis O. FIG. In FIG. 4B, a line E indicating the outline of the protrusion shape 13 is shown. From this line E, the protrusion shape 13 starts from the apex C of the distal end portion 13b (same as the center point of the bottom circle of the base portion 13a). A portion E ₀ in the range W of 100 nm on both sides in the width direction (the opposite direction of the bottom circle of the base portion 13a) is approximated to a quadratic curve with the point C as the origin, as shown in FIG. Then, a quadratic equation representing the quadratic curve ^{(y = ax 2 + bx +} c) 2 times the reciprocal of the value of coefficient a quadratic term of (1 / (2a)) is the radius of curvature.
As a population for calculating the radius of curvature, any 20 protrusions made of a metal oxide having a length exceeding 3 μm are used.

  The sum average length of the protrusion shape made of a metal oxide having a length exceeding 3 μm according to the present invention is calculated by observation with a scanning electron microscope (SEM) according to the following method. First, a cross section is obtained by cutting a metal oxide sample having a protrusion shape along a plane passing through the center of the upper surface of the metal oxide sample and extending in parallel with the longitudinal direction of the metal oxide having a protrusion shape. A predetermined range along the obtained cross section is observed with an SEM, and the entire side surface of the metal oxide having a plurality of projection shapes that can be observed from the cross section side within the range is a metal oxide having other projection shapes Only a metal oxide having a projection shape that can be observed without obstructing the field of view is calculated as a population.

  As a specific example of the protrusion shape, in the case of a rod shape, the diameter does not change from the root part to the tip part, the diameter does not change from the root part to the distance in the direction of the tip part, the diameter of the root part is small, the tip part Once the shape grows, the diameter decreases again, the shape gradually decreases as it goes from the root to the tip, a pyramid or cone, or a truncated cone or hemisphere from a distance near the tip Some of them have such a shape. Furthermore, in the case of a prismatic shape, the specific shape varies depending on the crystal structure, but when the metal oxide is zinc oxide, it is a hexagonal column, when it is aluminum oxide, it is a square column or hexagonal column, and when it is titanium oxide, it is a quadrangular column. There are many cases. Some prisms have other polygons in cross-sectional shape.

It is preferable that the central axes of the protrusion shapes are substantially parallel to each other. The fact that the central axes of the protrusions are substantially parallel to each other can be confirmed by a generally known method such as SEM, X-ray rocking curve method, or φ-scan method.
When the central axis of the protrusion shape is substantially parallel, the field emission electrons from the protrusion shape efficiently reach the surface for the electron-emitting device having the protrusion shape, and the surface that emits excitation light can be efficiently formed.
In addition, when the protrusion shape is made of a metal oxide crystal, the protrusion shape must be substantially parallel to each other and grown in the same direction as the crystal axis on which the protrusion shape is growing. Excellent in properties and preferable. Furthermore, it is preferable that the crystal axes of the metal oxide crystal are in the same direction, that is, the crystal axis orientation is aligned. For example, the fluctuation of the crystal axis orientation measured by the X-ray rocking curve method is within 10 degrees. It is preferably some 5 degrees or less.

It is also preferable that the metal oxide having a protruding shape is a single crystal. Whether the metal oxide is a single crystal can be confirmed by a generally known method such as a φ-scan method. When the metal oxide having a protrusion shape is a single crystal, it is preferable that the electric resistance of the metal oxide tends to be small and uniform field electron emission is likely to occur.
In the metal oxide having a protrusion shape, the metal species is group 1, group 2 excluding hydrogen, group 13 excluding boron, group 15 excluding nitrogen and phosphorus, Po and 3, 4, 5, 6, It is an oxide composed of elements belonging to Groups 7, 8, 9, 10, 11, and 12. Among these, Li, Be, Na, Mg, Al, Si, K, Ca, Ti, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, As, Sr, Y, Zr, Nb, Pd , Cd, In, Sn, Sb, Ba, W, Pb, Bi, Th are more preferable, and Mg, Al, Si, Ti, Mn, Fe, Ni, Cu, Zn, Ga, Y, Zr, In, Sn Ba is particularly preferred. These metals may be used alone or may be a metal oxide having a plurality of types of metals.

Metal ratio of metal species in metal oxides and metal oxides having multiple types of metals affects the shape of metal oxides with formed protrusions, especially the length distribution and density of protrusions. There is.
Specific examples of the metal oxide having a protrusion shape include known metal oxides such as titanium oxide, strontium titanate, tungsten oxide, zinc oxide, tin oxide, and niobium oxide. Moreover, the metal oxide doped with other metal atoms like aluminum dope zinc oxide is also mentioned. Of course, other metal oxides may be used.
The metal oxide having a protrusion shape may be crystalline or amorphous, but it is preferable that the metal oxide is crystalline because it is easy to form protrusion shapes substantially parallel to each other. The crystalline material may be one or more types of single crystals, polycrystals, one or more types of semi-crystalline substances having a crystalline part and an amorphous part at the same time, or a mixture thereof. Also good. Particularly preferred is a single crystal. When the metal oxide having a protrusion shape is a single crystal, it is preferable that the electric resistance of the metal oxide tends to be small and uniform field electron emission is likely to occur.

In the metal oxide having the protrusion shape, the shape of the portion excluding the protrusion shape may be any as long as it has a substantially flat surface and / or curved surface, but a plate shape having a large surface area with respect to the thickness is preferable. Further, in the case of a plate shape, it is preferable that the surface having the protrusion has the maximum surface area compared to other surfaces.
In the field emission type electron-emitting device of the present invention, it may be necessary to obtain field electron emission by generating a lower electric field at the tip of the protrusion shape depending on the application. In this case, it is also preferable to further coat a substance having a work function lower than that of the substance forming the outermost surface part of the protrusion shape. More preferably, the work function of the substance that further covers the projection-shaped leading edge is 3/4 or less of the work function of the substance that forms the outermost surface of the projection-shaped leading edge before the coating of the substance, and particularly preferably 2 / 3 or less.

As a method for measuring the work function, a method for obtaining from the limit wavelength of photoelectron emission, a temperature dependence of the thermionic current density, a field strength dependence of the thermionic current density, a contact potential difference with a standard sample, etc. are generally known. Either method may be used.
As a specific example of a combination of a metal oxide having a protrusion shape and a substance having a lower work function, the metal oxide having a protrusion shape has a lower work function with respect to zinc oxide (work function 5.2 eV). Examples of the material include carbon nitride (work function 2.1 eV) and amorphous carbon (work function 0.7 eV).

In the field emission type electron-emitting device of the present invention, protrusions made of a metal oxide have a predetermined density. For this reason, a space | gap exists between protrusion shape. For this reason, depending on the situation of use, there is a possibility that deformation or breakage of the projection shape may occur during use. In order to prevent this, for example, fixing between the protrusion shapes with an organic substance such as a thermoplastic resin, a thermosetting resin, an elastomer, an instantaneous adhesive such as cyanoacrylate, an inorganic substance such as glass or ceramics, a metal, etc. You can also. An insulating material is preferable as the substance for fixing between the protrusion shapes.
The field emission electron-emitting device of the present invention may be formed on a substrate.
In the portion of the substrate on which the field emission type electron-emitting device of the present invention is formed, it is preferable that the substrate is substantially flat so that the lengths of the protrusions are uniform.

Examples of the material of the substrate include a metal oxide single crystal such as aluminum oxide, a semiconductor single crystal, a ceramic, a metal containing silicon, glass, and plastic. When a glass plate or a plastic plate is used, it is preferable that the surface is oriented. Among these, a substrate material preferably used is a metal containing silicon, a metal oxide, or a single crystal of a semiconductor such as ZnTe, GaP, GaAs, or InP.
When a substrate made of a single crystal of metal oxide or semiconductor is used, the lattice constant of the substrate as the single crystal seed is the lattice constant of the metal oxide crystal seed having a protrusion shape to be epitaxially grown on the substrate surface. It is preferable to select the closest one. The measurement of the lattice constant can be performed by a conventionally known method such as a wide angle X-ray diffraction method.
As the single crystal seed used as the material of the substrate, the ratio (A / B) between the lattice constant (A) of the metal oxide having a protrusion shape and the single crystal seed (B) forming the substrate is preferably 0.8. To 1.2, more preferably 0.9 to 1.1, and still more preferably 0.95 to 1.05.
Particularly preferably used as the single crystal seed as the material of the substrate is silicon, metal oxides such as aluminum oxide, magnesium oxide, SrTiO _{3 and the} like.

A preferred method for producing a metal oxide having a protruding shape constituting the field emission type electron-emitting device of the present invention includes the following steps.
That is, Li, Be, Na, Mg, Al, Si, K, Ca, Ti, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, As, Sr, Y, Zr, Nb, Pd, A metal compound of at least one metal selected from Cd, In, Sn, Sb, Ba, W, Pb, Bi, Th, wherein the metal compound is a β-diketone, ethylenediamine, piperidine, Piperazine, cyclohexanediamine, tetraazacyclotetradecane, ethylenediaminetetraacetic acid, ethylenebis (guanide), ethylenebis (salicylamine), tetraethyleneglycol, aminoethanol, glycine, triglycine, naphthyridine, phenanthroline, pentanediamine, pyridine, salicylaldehyde , Salicylideneamine, porphyrin, thi Complexes having at least one selected from urea, and conjugated diene groups including alkoxide groups, carbonyl groups, carboxyl groups, alkyl groups, alkenyl groups, phenyl or alkylphenyl groups, olefin groups, aryl groups, cyclobutadiene groups Selected from organic metal compounds having at least one selected from dienyl groups including cyclopentadienyl groups, triene groups, arene groups, trienyl groups including cycloheptatrienyl groups, and halides thereof. A metal compound having a group, wherein the metal compound is heated to a metal compound gas of 1 wt% or more (1), and the metal compound gas is blown onto the substrate in the air to have a projection shape And a step (2) of forming a metal oxide.

First, a method for turning a metal compound as a raw material into a gas will be described.
Examples of the method for making the metal compound into a gas include a method in which the metal compound is heated to a temperature at which the vapor pressure becomes sufficiently high to make it into a gas. In the present invention, the vapor of the metal compound obtained after gasification is cooled, the metal compound is sprayed in a liquid state, the metal compound is ground in a solid state and then sprayed with a carrier gas, The so-called fine particles can be sprayed in the form of mist.
The preferred temperature for heating the metal compound to gas is 30-600 ° C, more preferably 50-300 ° C. When the temperature at which the metal compound is heated exceeds 600 ° C., the metal compound preferably used in the present invention undergoes thermal decomposition before reaching the substrate, and it is difficult to form a metal oxide on the substrate, which is not preferable.

  In this step, it is preferable that oxygen or water is not present in the system or the amount thereof is extremely small. Particularly preferably, the moisture pressure in the pipe containing the metal compound gas is less than 200 Pa. Otherwise, a reaction between the metal compound and oxygen and / or water may occur, which may cause clogging in the piping or may not form a desired form of metal oxide on the substrate. However, when the reaction rate of the metal compound to be used with oxygen and water is extremely slow, oxygen and water may coexist in the system. Particularly, for example, when the nozzle opening area is large or the nozzle openings are densely present, the metal compound gas is generated at the end of the pipe and the portion where the metal oxide having the protruding shape is formed. When not sufficiently mixed with oxygen or water, it is preferable to coexist or introduce oxygen or water as a reaction medium in the system beforehand.

  When oxygen or water coexists or is introduced into the system, an inert gas may be used as a carrier gas. Particularly preferably, the water pressure in the pipe containing the metal compound gas is less than 200 Pa, and only oxygen, or oxygen and an inert gas are allowed to coexist or introduced into the system. In the case where only oxygen or oxygen and an inert gas are allowed to coexist or introduced into the system, oxygen or oxygen and the inert gas are once dried and then allowed to coexist so that the water pressure in the system is less than 200 Pa. Or it is preferable to introduce. Some metal compounds, which are raw materials used in the preferred production method of the present invention, form metal compounds even when heated in the presence of oxygen or in the presence of water. In the case of such a metal compound, the rate of formation of the metal oxide by heating in the presence of water is significantly greater than the rate of formation of the metal oxide by heating in the presence of oxygen. May not take the desired form. Conditions such as a place where the metal compound gas is mixed with oxygen and water, temperature, mixing ratio, and the like depend on the reactivity of the metal compound gas, the concentration of the metal compound gas, oxygen, and water. In addition, conditions such as the location where the metal compound gas is mixed with oxygen and water, temperature, mixing ratio, etc. may affect the shape of the metal oxide having the formed protrusion shape, particularly the length distribution and existence density of the protrusion shape. There is.

The air used in the present invention may be added with dehydration treatment or oxygen and / or water as necessary.
As the metal compound that is a raw material, a compound that reacts with oxygen and / or water to form a target metal oxide is used.
As such a metal compound, any metal compound can be used as long as it is an above-described metal compound.
Among these, a metal complex containing a β-diketone as a ligand, a metal alkoxide, and an alkyl metal are more preferable. Examples of β-diketone ligands include acetylacetone ligand, dipivaloylmethanato ligand, diisobutyrylmethanato ligand, isobutyrylpivaloylmethanato ligand, 2,2,6,6 -Tetramethyl-3,5-octanedionate ligand, 6-ethyl-2,2-dimethyl-3,5-octanedionate ligand and the like. Examples of the alkoxide group include methoxy group, ethoxy group, propoxy group, butoxy group and the like. Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, and a butyl group.
The metal compound gas obtained as described above is then moved toward the substrate in an atmosphere in which air of a predetermined pressure exists, and the metal compound is reacted with oxygen and / or water to form a metal on the substrate. Grown as oxide.

  The metal compound gas alone may be moved to the substrate surface as it is, or may be positively moved using a carrier gas and sprayed from the nozzle to the substrate in a mixed state with the carrier gas. The flow rate of the carrier gas in this case varies depending on the temperature of the vaporized and / or finely divided metal compound and the atmosphere of the space in which the substrate is installed, but the substrate installation space is at room temperature and atmospheric pressure. For this, the flow rate of the carrier gas is preferably set so that the spatial volume value is 20 / min or less, more preferably 5 / min or less. Here, the space volume value refers to the flow rate R (volume per minute) of the carrier gas and the heating tank (the space into which the carrier gas is introduced) in which the metal compound is gasified and / or finely divided in the step (1). ) To the volume V (R / V).

The carrier gas is not particularly limited as long as it does not react with the raw material metal compound. Specific examples include nitrogen gas, inert gases such as helium, neon, and argon, carbon dioxide gas, organic fluorine gas, and organic substances such as heptane and hexane. Among these, an inert gas is preferable from the viewpoint of safety and economy. Nitrogen gas is particularly preferred from the economical aspect.
When employing a method of spraying a metal compound from a nozzle onto a substrate using a carrier gas, it is preferable that the distance between the nozzle outlet and the substrate is within a predetermined range. In this range, the long axis (the length of the long side when the cross section is rectangular, the length of one side when the cross section is rectangular) is L, and the long axis of the opening of the air outlet is the surface of the substrate 11. When the distance is K, the ratio (K / L) is preferably 0.01 or more and 1 or less, more preferably 0.05 or more and 0.7 or less, and 0 More preferably, it is set to 1 or more and 0.5 or less. When this ratio (K / L) exceeds 1, the efficiency with which a metal compound is converted into a metal oxide decreases. In addition, the form of the metal oxide having the formed protrusion shape, particularly the length distribution and existence density of the protrusion shape may be affected.

The atmosphere in the installation space of the substrate may be under reduced pressure, normal pressure, or increased pressure. However, high pressure reduction, for example, ultra-vacuum is not preferable because the growth rate of the metal oxide is slow and the productivity is poor. When carried out under pressure, there is no problem with the growth rate of the metal oxide, but it is not preferable because equipment for pressurization is required. Therefore, the atmosphere of the substrate installation space is preferably 1.01 × 10 ^{2 to} 2.03 × 10 ⁶ Pa, more preferably 1.01 × 10 ^{4 to} 1.01 × 10 ⁶ Pa. The atmospheric pressure is most preferable.
The substrate temperature is a factor that determines the diffusion distance of the raw material on the substrate surface and / or the growth rate of the metal oxide and the length distribution of the protrusion shape.

The number of metal oxide crystals per unit area, that is, the nucleation density is determined by the diffusion distance. In general, when the substrate temperature is high, the nucleation density decreases and the number of metal oxide crystals per unit area decreases. When the substrate temperature is low, the nucleation density increases and the number of metal oxide crystals per unit area increases.
Depending on the growth rate of the metal oxide, the length and length distribution of the metal oxide, particularly the protrusion shape, per unit area are determined. In general, when the substrate temperature is high, the growth rate of the metal oxide increases, and the length of the protrusion shape increases. Also, the length distribution becomes large. When the substrate temperature is low, the growth rate of the metal oxide becomes low, and the length of the protrusion shape becomes short. Also, the length distribution becomes smaller. Therefore, the substrate temperature may be set according to the required formation density and length distribution of the protrusion shape. As this substrate temperature, 0 degreeC-800 degreeC are preferable, 20 degreeC-800 degreeC are more preferable, and the range of 100 degreeC-700 degreeC is further more preferable.

The temperature distribution until the metal compound gas reaches the substrate may also be a factor that determines the diffusion distance of the raw material on the substrate surface and / or the growth rate of the metal oxide and the length distribution of the protrusion shape. Preferably, the temperature of the interface for releasing the metal compound gas into the air is T ₁ , the temperature at half the distance between the end of the pipe and the substrate at the center of the cross section of the opening interface is T ₂ , and the temperature of the substrate is T _In the case of ₃ , T ₁ <T ₂ <T ₃ . When T ₁ > T ₃ , the existence density of the protrusion shape becomes too high, which is not preferable. Also, the growth rate is low, which is not preferable. In the case of T ₁ > T ₂ <T ₃ , the existence density of the protrusion shape becomes too high, which is not preferable. In addition, the length distribution of the protrusion shape becomes too large, which is not preferable.

The interface for releasing the metal compound gas of the present invention into the air is a metal compound heating tank, a pipe connected to the metal compound heating tank, a nozzle connected to the pipe, etc., and a closure connected to the metal compound heating tank It refers to the interface between the system opening and the air.
The center of the cross section of the opening interface of the present invention is a closed opening connected to a metal compound heating tank, such as a metal compound heating tank, a pipe connected to the metal compound heating tank, and a nozzle connected to the pipe. This is a central part when the opening surface obtained by observing the interface portion in air with a cross section perpendicular to the normal direction of the substrate is a circle or a center of gravity when approximating a polygon. When there are a plurality of openings, the center of the part surrounded by the periphery of the openings is a center of the part observed in a cross section perpendicular to the normal direction of the substrate, or the center of gravity of the part approximated by a polygon I mean.

As a specific method of satisfying T ₁ <T ₂ <T ₃ , a method of heating the periphery of the opening of the closed system connected to the metal compound heating tank and the substrate surface, and a method of heating the closed system connected to the metal compound heating tank A method of using a radiant heat of the substrate heating by providing a partition plate etc. around the opening and the substrate surface, and a nozzle connected to the metal compound heating tank via a pipe covering the substrate heating table to radiate the radiant heat of the substrate heating. There are methods to use and methods to combine these methods. Of course, any other method can be used as long as T ₁ <T ₂ <T ₃ can be satisfied by a generally known method.

The present invention will be described more specifically based on examples, but the present invention is not limited to these examples.
[Example 1]
The apparatus shown schematically in FIG. 1 was used. This manufacturing apparatus includes a supply source 51 of nitrogen that is a carrier gas, a flow meter 57 that adjusts the flow rate of the carrier gas, heating tanks 53a and 53b that vaporize a metal compound that is a raw material, a heating tank 53a A pipe 54 to be introduced into 53b, pipes 55 and 59 for directing the metal compound vaporized in the heating tanks 53a and 53b to the outlet 58, a substrate stage 56 for holding the substrate 11 in a heated state, and air as a reaction medium And a pipe 60 for introducing the flow-controlled air into the pipe 59. The pipe 54 is provided with a liquid nitrogen trap 52. The heating tanks 53a and 53b are arranged in series. The flow meter 57 is provided with a needle valve 57a so that the gas can be turned on / off and the gas flow rate can be adjusted. The liquid nitrogen trap 52 is for removing moisture contained in the carrier gas supplied from the nitrogen supply source 51.

In this example, a compressed nitrogen cylinder (moisture pressure of 1.4 Pa or less, manufactured by Fuji Acetylene Co., Ltd.) was used as a nitrogen supply source. Furthermore, the source 61 of air is air cooled to -40 ℃ Compressors air dryer pressurized with (not shown) to 7.07 × 10 ⁵ Pa (not shown) to remove moisture in the air Yes. The moisture pressure in the air at this time was 3.4 Pa.
Before entering the outlet 58, the carrier gas and the raw material gas are mixed in the pipe 59. A blowout port 58 having a predetermined shape is connected to the distal end portion of the pipe 59, and an opening 58 a of the blowout port 58 is formed on the entire surface on the substrate 11 where the gas from the pipe 59 forms the metal oxide 12. It is formed to be blown out. Further, the pipes 54, 55, 59 and the blowout port 58 (portions indicated by triple lines and double lines in FIG. 1) are heated by a ribbon heater. In Example 1, the outlet 58 was a hollow cone having an inner diameter of 80 mmφ, a height of 46 mm, and a thickness of 10 mm. There is a joint portion with the pipe 59 at the apex portion of the cone, and an opening 58a is formed on the bottom surface (a portion forming a circle) of the cone. The openings 58a of the blowout ports 58 have 1 mmφ holes arranged in a staggered manner with a center distance of 2 mm. The range of the portion where the holes are arranged is 20 mm square by the distance between the centers of the outermost holes.

Al (C ₅ H ₇ O ₂ ) ₃ was charged into the heating bath 53a and heated to 104 ° C. Zn (C ₅ H ₇ O ₂ ) ₂ was charged into the heating tank 53b and heated to 108 ° C. The outlet 58 was heated to 200 ° C. This temperature is T _1.
An n-Si (100) substrate (manufactured by SUMCO Co., Ltd., resistivity ≦ 0.1Ω · cm, 25 mm square) is used as the substrate 11 at the center of the portion where the hole of the opening 58a of the outlet 58 is disposed. Arranged. The substrate 11 was provided with a 0.5 mm thick quartz plate having a 15 mm square opening as a mask, and the formation site of the metal oxide 12 was determined. In the quartz plate, the center of the opening is made to coincide with the center of the portion where the hole of the opening 58a of the blowout port 58 is arranged, and the side of the opening of the quartz plate and the outermost part of the opening 58a of the blowout 58 are arranged. The lines formed from the centers of the holes were arranged so as to be parallel to each other. The substrate 11 was heated to 650 ° C. by the substrate stage 56. This temperature is T _3. At the center of the portion where the hole of the opening 58a of the blowing port 58 is disposed, the temperature (T ₂ ) at ½ of the distance between the end of the opening 58a of the blowing port 58 and the substrate 11 was 245 ° C. .

Dry nitrogen gas was introduced into the heating tank 53a at a flow rate of 2.5 dm ³ / min. At the same time, dry air was introduced into the pipe 59 connected to the outlet 58 at a flow rate of 2.5 dm ³ / min. 60 minutes after the start of spraying, the obtained metal oxide 12 was removed together with the substrate 11.
With respect to the obtained metal oxide 12, a circuit as shown in FIG. 2 was formed, and field emission characteristics and light emission characteristics were evaluated.
The base plate G2 coated with the conductive film D2 was attached so that the substrate 11 on which the metal oxide 12 was formed was in contact with and conductive with the conductive film side of the base plate G2.
A lead electrode 4 made of stainless steel mesh was attached to the conductive film D2 via a partition member 6b made of alumina. The distance between the conductive film D2 and the extraction electrode 4 is 250 μm, and the conductive film D2 and the extraction electrode 4 are electrically insulated. The stainless steel mesh constituting the extraction electrode 4 is formed with 0.3 mm square holes at intervals of 0.5 mm. This 0.3 mm square hole becomes a hole 14 that exposes the tip of the protrusion.

Using the apparatus schematically shown in FIG. 1, phosphor H was formed on the transparent conductive film side of quartz substrate G1 coated with transparent conductive film D1 by the following procedure.
The side on which the transparent conductive film D1 of the quartz substrate G1 is formed is placed facing the blowing port 58 and heated to 650 ° C. Y (C ₁₁ H ₁₉ O ₂ ) ₃ , (C ₁₁ H ₁₉ O ₂ = dipivaloylmethanato, hereinafter referred to as “DPM”) and Eu (DPM) ₃ are 2/1 in the heating bath 53b. Charge by weight and heat to 220 ° C. The heating tank 53a, the pipe 55, and the outlet 58 are heated to 230 ° C. by a ribbon heater.

A quartz substrate G1 (25 mm square) coated with the transparent conductive film D1 was disposed at the center of the portion where the hole of the opening 58a of the outlet 58 is disposed. The quartz substrate G1 coated with the transparent conductive film D1 was disposed using a quartz plate having a thickness of 0.5 mm having a square opening of 15 mm square as a mask, and the formation site of the phosphor H was determined. In the quartz plate, the center of the opening is made to coincide with the center of the portion where the hole of the opening 58a of the blowout port 58 is arranged, and the side of the opening of the quartz plate and the outermost part of the opening 58a of the blowout 58 are arranged. The lines formed from the centers of the holes were arranged so as to be parallel to each other. The quartz substrate G1 coated with the transparent conductive film D1 was heated to 700 ° C. by the substrate stage 56.
In this state, nitrogen is introduced from the nitrogen supply source 51 into the pipe 54 at a flow rate of 1.2 dm ³ / min, whereby a mixed gas of a metal compound gas and nitrogen gas is blown out through the pipe 55. The phosphor H is formed by spraying from 58 on the transparent conductive film D1 of the quartz substrate G1 for 50 minutes. Thereby, Y ₂ O ₃ : Eu is formed as the phosphor H. At this time, air was not introduced into the outlet 58.

A quartz substrate G1 coated with the phosphor H and the transparent conductive film D1 was mounted on the extraction electrode 4 via a partition member 6a made of alumina. At this time, the surface on which the phosphor H is formed faces the extraction electrode 4 side. In addition, the portion where the phosphor H is formed is arranged so as to coincide with the portion where the metal oxide 12 having a protruding shape is formed as viewed from the vertical direction. The distance between the transparent conductive film D1 and the extraction electrode 4 is 10 mm, and the transparent conductive film D1 and the extraction electrode 4 are electrically insulated.
The structure thus fabricated was placed in a vacuum chamber. At this time, the transparent conductive film D1 is on the positive side of the variable DC power source B2 having a voltmeter through a terminal (not shown) of the vacuum chamber, and the extraction electrode 4 is a variable DC having a voltmeter through a terminal (not shown) of the vacuum chamber. Connected to the positive side of power supply B1. Further, an ammeter A was connected to the conductive film D2 through a terminal (not shown) of a vacuum chamber, and then connected to the negative electrode side of the variable DC power sources B1 and B2 having voltmeters and to the ground. The current value indicated by the ammeter A is the value of electrons emitted from the electron-emitting device (cathode current value). In FIG. 2, the portion on the left side from the dotted line exists in the vacuum chamber, and the portion on the right side from the dotted line exists outside the vacuum chamber. Further, the upper surface portion of the vacuum chamber is made of glass, and the quartz substrate G1 coated with the phosphor H and the transparent conductive film D1 can observe the light emission state from the upper surface portion.

After sealing the vacuum chamber, the inside of the vacuum chamber was evacuated to 7 × 10 ^{−6 to} 7 × 10 ⁻⁵ Pa. The DC variable power source B2 was fixed at 3000V. The DC variable power source B1 was boosted at a rate of 50 V / min until a stable cathode current value was obtained from 500V. Thereafter, the voltage of the DC variable power supply B1 was adjusted so as to show a voltage value indicating a stable cathode current value of 100 to 150 μA / cm ² or a voltage value of about 2500 to 3000 V indicating a stable cathode current value. . The current value at this time was set as the cathode current shown in Table 1.
From the vertical direction of the phosphor H, the area of the portion where the phosphor H emits light was visually observed. At this time, the portion that emits light and the portion that does not emit light are distinguished through a transparent plate in which a lattice is drawn in 1 mm length and width in the range of 15 mm × 15 mm of the same size as the surface on which the phosphor H exists. Thus, the emission area ratio was calculated and shown in Table 1.

After the evaluation of the field emission characteristics and the light emission characteristics, the metal oxide 12 was taken out together with the substrate 11 from the vacuum chamber. The metal oxide 12 thus taken out was vapor-deposited on the metal oxide as a conductive material together with the substrate 11 by sputtering, and then divided into two for each substrate 11 at the center. Using a SEM, one sample was observed from the cross-sectional direction, and the length of each protrusion shape and the curvature radius of the protrusion shape were measured. Another sample was observed from the plane direction, and the density of protrusions and the diameter of each protrusion in terms of a circle were measured. Arbitrary protrusion shape made of metal oxide having a length of 3 μm or more with the length of each protrusion shape measured by the method of the present invention, the radius of curvature of each protrusion shape, and the circle-converted diameter of each protrusion shape as a population. 100 total average lengths (χ), standard deviations (σ), abundance densities, circle-converted diameters, and curvature radii were calculated and shown in Table 1. Further, the number of protrusions having a length of χ ≧ 5 μm and a length of χ + σ / 2 or more from the same population, the maximum length L _max , and the minimum length L _min are observed, and L _min / L _max is calculated, It is shown in Table 1.
In addition, the direct current in which the cathode current shown in Table 1 was obtained by subtracting the sum average length (χ) (μm) of 100 arbitrary protrusion shapes made of metal oxide exceeding the protrusion shape length of 3 μm from 250 μm. The voltage of the variable power source B1 was divided. This value is shown in Table 1 as an extraction electric field.

[Example 2]
The metal oxide 12 was formed by the same method as in Example 1 except that the time for forming the metal oxide 12 was 180 minutes, and field emission characteristics and light emission characteristics were evaluated. The results are shown in Table 1.
[Example 3]
The metal oxide 12 was formed by the same method as in Example 2 except that the temperature of the heating bath 53a was 96 ° C., and the field emission characteristics and the light emission characteristics were evaluated by the same methods as in Example 1. The results are shown in Table 1.

[Example 4]
Except that the air flow rate and 3.0dm ³ / min to form a metal oxide 12 in the same manner as in Example 2, was evaluated for field emission and luminescent characteristics in the same manner as in Example 1. The results are shown in Table 1.
[Example 5]
The temperature of the heating tank 53a was 107 ° C., and the temperature of the heating tank 53b was 121 ° C. Further, the metal oxide 12 was formed by the same method as in Example 1 except that the nitrogen flow rate and the air flow rate were 4.0 dm ³ / min, and the temperature of the substrate 11 was 700 ° C., and the field emission characteristics and the light emission characteristics were evaluated. Went. The results are shown in Table 1.

[Example 6]
Metal oxide 12 was formed by the same method as in Example 2. Amorphous carbon nitride was formed on the obtained metal oxide 12 using the apparatus (microwave plasma CVD apparatus) shown in FIG.
The microwave plasma CVD apparatus comprises a source 71 of argon as the gas generating a plasma, a flow meter 81 for adjusting the flow rate of the gas to produce a plasma, P ₂ O to remove moisture in the gas to produce a plasma _{5 has a} trap 70, a pipe 73 for introducing a gas for generating plasma into the chamber 75, and a microwave generator 76 for generating plasma by applying a microwave to the gas for generating plasma. The raw material for forming the carbon nitride film is vaporized by the raw material supply source 72, passes through the P ₂ O ₅ trap 70 for removing moisture, and passes through the outlet 80 of the piping 74 to the substrate 11 on the substrate stage provided in the chamber 75. Be blown into. At this time, the raw material discharged from the blowing port 80 is decomposed by Ar plasma, and an amorphous or microcrystalline carbon nitride film is formed on the metal oxide 12 on the substrate 11. The chamber 75 is connected to a mechanical booster 77 and a rotary pump 78, and is set so that the pressure in the chamber becomes 10 Pa. The microwave is set to have a frequency of 2.45 GHz and 100 W.

Prior to forming amorphous carbon nitride on the surface of the metal oxide 12, amorphous carbon nitride was formed on a flat substrate, and the work function was measured.
A 30 mm square n-Si (100) substrate was placed on the sample stage of the microwave plasma CVD apparatus.
As a carbon nitride raw material, 0.5 g of CH ₃ CN is vaporized at room temperature (23 ° C.) in the raw material supply tank 72, moisture is removed with a P ₂ O ₅ trap 70, and introduced into the chamber 75. It sprayed on the surface of the n-Si (100) board | substrate heated at 100 degreeC from the blower outlet 80 arrange | positioned at 5 mm intervals from the top. On the other hand, Ar gas is supplied as a gas for generating plasma at a flow rate of 100 sccm, and a microwave is applied to the Ar gas by the microwave generator 76, and the n-Si (100) substrate is sprayed by plasma generated. The source gas was decomposed to form amorphous carbon nitride on the surface of the n-Si (100) substrate. The obtained n-Si (100) substrate on which amorphous carbon nitride was formed was taken out, and the work function was calculated by the Kelvin method. The work function of the formed amorphous carbon nitride was 2.1 eV.

Next, amorphous carbon nitride was formed on the surface of the metal oxide 12. The metal oxide 12 obtained above was placed on the sample stage of the microwave plasma CVD apparatus together with the substrate 11.
As a carbon nitride raw material, 0.5 g of CH ₃ CN is vaporized at room temperature (23 ° C.) in the raw material supply tank 72, moisture is removed with a P ₂ O ₅ trap 70, and introduced into the chamber 75. It sprayed on the surface of the metal oxide 12 formed in the board | substrate 11 heated to 100 degreeC from the blower outlet 80 arrange | positioned at 5 mm intervals from the top. On the other hand, Ar gas is supplied as a gas for generating plasma at a flow rate of 100 sccm, and the metal oxide 12 formed on the substrate 11 is generated by applying plasma to the Ar gas by a microwave generator 76. The raw material gas blown on the substrate 11 was decomposed to form amorphous carbon nitride on the surface of the metal oxide 12 formed on the substrate 11.
The obtained metal oxide 12 on which amorphous carbon nitride was formed was evaluated for field emission characteristics and light emission characteristics by the same method as in Example 1 together with the substrate 11. The results are shown in Table 1.

[Example 7]
Metal oxide 12 was formed by the same method as in Example 2. The extracted metal oxide 12 was deposited on the metal oxide as a conductive material by sputtering together with the substrate 11, and then field emission characteristics and light emission characteristics were evaluated in the same manner as in Example 1. The results are shown in Table 1.
[Comparative Example 1]
The temperature of the heating bath 53 b was set to 121 ° C., and the substrate 11 was heated to 670 ° C. by the substrate stage 56. Further, the formation of the metal oxide 12, the field emission characteristics and the light emission characteristics were evaluated by the same method as in Example 1 except that the time for forming the metal oxide 12 was 30 minutes. The results are shown in Table 2.

[Comparative Example 2]
The needle valve 57a provided in the flow meter 57 communicating with the dry air was closed, and the metal oxide 12 was formed for 120 minutes without introducing the dry air into the pipe 59. Except for this, the formation of the metal oxide 12, the field emission characteristics, and the light emission characteristics were evaluated in the same manner as in Example 1. The results are shown in Table 2.
[Comparative Example 3]
The heating tank 53a was heated to 150 ° C. without adding Al (C ₅ H ₇ O ₂ ) _3, and the temperature of the heating tank 53b was heated to 121 ° C. Further, the formation of the metal oxide 12, the field emission characteristics, and the light emission characteristics were evaluated in the same manner as in Example 1 except that the time for forming the metal oxide 12 was 60 minutes. The results are shown in Table 2.

[Comparative Example 4]
As the blowout port 58, a rectangular pyramid hollow portion formed inside a stainless steel rectangular parallelepiped having a size of 90 mm × 20 mm and a height of 50 mm was used. The hollow part of the truncated pyramid has a 5mm square in the center of the upper surface of the stainless steel rectangular parallelepiped, and a 90mm x 0.5mm hole in the center of the bottom of the stainless steel rectangular parallelepiped. Each of the corners of the opposite corner is connected by a straight line. A hole of 5 mm square formed at the center of the upper surface of the stainless steel rectangular parallelepiped is connected to the pipe 59, and a hole of 90 mm × 0.5 mm formed at the center of the bottom of the stainless steel rectangular parallelepiped becomes the opening 58a. Except for setting the time for forming the metal oxide 12 to 60 minutes, the formation of the metal oxide 12, the field emission characteristics, and the light emission characteristics were evaluated in the same manner as in Example 1. The results are shown in Table 2.

[Comparative Example 5]
Metal oxide 12 was formed in the same manner as in Comparative Example 3. The obtained metal oxide 12 formed amorphous carbon nitride together with the substrate 11 by the same method as in Example 5. The field emission characteristics and the light emission characteristics were evaluated in the same manner as in Example 1. The results are shown in Table 2.
[Comparative Example 6]
Metal oxide 12 was formed in the same manner as in Comparative Example 3. The extracted metal oxide 12 was deposited on the metal oxide as a conductive material by sputtering together with the substrate 11, and then field emission characteristics and light emission characteristics were evaluated in the same manner as in Example 1. The results are shown in Table 2.

  According to the present invention, a field emission type electron-emitting device capable of emitting electrons uniformly with low power consumption per unit area can be obtained. This field emission type electron emission device can be effectively used as a field emission type electron emission device of a conventionally known light source such as an image / video display device, illumination, and a micro vacuum tube.

It is a schematic block diagram which shows the manufacturing apparatus of the metal oxide which has a protrusion shape. It is a schematic block diagram of the apparatus for measuring a field emission characteristic. It is a schematic block diagram which shows a microwave plasma CVD apparatus. It is a figure for demonstrating the curvature radius of a protrusion front-end | tip part. It is a schematic block diagram which shows an example of the conventional array-like field emission cold cathode (field emission type electron-emitting device).

Explanation of symbols

A Ammeter B1 DC variable power supply B2 DC variable power supply D1 Transparent conductive film D2 Conductive film H Phosphor G1 Quartz substrate G2 Base plate 4 Lead electrode 6a Partition member 6b Partition member 8 High conductivity silicon substrate 11 Substrate 12 Projection shape Metal oxide having 13 Protrusion shape 13a Base portion 13b Tip portion 14 Hole exposing tip portion 30 Insulating layer 31 Electron emission source 51 Nitrogen supply source 52 Liquid nitrogen trap 53a Heating bath 53b Heating bath 54 Piping 55 Piping 56 Substrate stage 57 Flow meter 57a needle valve 58 outlet 58a opening 59 pipe 60 pipe 61 air supply 70 P ₂ O ₅ trap 71 argon supply source 72 raw material supply source 73 pipe 74 pipe 75 chamber 76 microwave generator 77 mechanical booster 78 rotary pump 79 two Dorubarubu 80 blow-out port 81 flow meter

Claims (15)

Arbitrary protrusions made of metal oxide having a density of 5 to 100,000 per 1 mm × 1 mm area on the metal oxide surface, and having a protrusion shape made of a metal oxide having a length of 3 μm When the sum average length of 100 shapes is χ and the standard deviation is σ, the maximum length of the protrusion shape having a length of χ ≧ 5 μm and χ + σ / 2 or more is L _max , and the minimum length is L _min In this case, a field emission electron-emitting device made of a metal oxide, wherein 1 ≧ L _min / L _max ≧ 1/3. In the protrusion shape made of a metal oxide having a length χ + σ / 2 or more, the number of protrusion shapes having a length (L _min + L _max ) / 2 or more is 1 / of the number of protrusion shapes having a length χ + σ / 2 or more. The field emission electron-emitting device according to claim 1, wherein the number is 3 or more. 3. The field emission electron-emitting device according to claim 1, wherein a sum-average circle-converted diameter of the protrusion-shaped cross section made of a metal oxide having a length of 3 μm or more is 0.01 to 100 μm. The field emission electron-emitting device according to any one of claims 1 to 3, wherein a ratio of a length of a projection-shaped cross section made of a metal oxide having a length exceeding 3 µm to a circle-converted diameter is 1 or more. The field emission electron-emitting device according to any one of claims 1 to 4, wherein a radius of curvature of the protrusion-shaped tip portion made of a metal oxide having a length exceeding 3 µm is 100 nm or less. 6. The field emission electron-emitting device according to claim 1, wherein the central axes of the protrusions are substantially parallel to each other. The field emission electron-emitting device according to claim 1, wherein the metal oxide is a metal oxide single crystal. The metal in the metal oxide contains at least one of Mg, Al, Si, Ti, Mn, Fe, Ni, Cu, Zn, Ga, Y, Zr, In, Sn, and Ba. The field emission electron-emitting device according to any one of 1 to 7. The field emission type according to any one of claims 1 to 8, wherein at least a tip portion of the protrusion shape is coated with a material having a work function smaller than that of a metal oxide constituting the protrusion shape. Electron emission device. The substance having a work function smaller than the work function of the metal oxide constituting the protrusion shape is at least one film of amorphous microcrystalline carbon nitride, microcrystalline carbon nitride, amorphous carbon, microcrystalline carbon, and diamond. The field emission type electron-emitting device according to claim 9. The field emission electron-emitting device according to any one of claims 1 to 10, wherein the protrusion shape is fixed with at least one material selected from an organic substance, an inorganic substance, and a metal. Li, Be, Na, Mg, Al, Si, K, Ca, Ti, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, As, Sr, Y, Zr, Nb, Pd, Cd, Β-diketone, ethylenediamine, piperidine, piperazine, cyclohexanediamine, tetraazacyclotetradecane, ethylenediaminetetra of at least one metal selected from the metal group consisting of In, Sn, Sb, Ba, W, Pb, Bi, Th Choose from acetic acid, ethylenebis (guanide), ethylenebis (salicylamine), tetraethylene glycol, aminoethanol, glycine, triglycine, naphthyridine, phenanthroline, pentanediamine, pyridine, salicylaldehyde, salicylideneamine, porphyrin, thiourea A metal with coordinated ligand A metal selected from the group consisting of alkoxide, carbonyl, carboxyl, alkyl, alkenyl, phenyl or alkylphenyl, olefin, aryl, cyclobutadiene and other conjugated diene groups, Among organometallic compounds in which one or more selected from a dienyl group such as a pentadienyl group, a triene group, an arene group, and a trienyl group such as a cycloheptatrienyl group are bonded, and halides thereof A step (1) of heating a metal compound selected from 1 to a metal compound gas having a concentration of 1% by weight or more;
A step (2) of blowing the metal compound gas onto a substrate in air to form a metal oxide having a protrusion shape;
The temperature of the interface that emits the metal compound gas into the air is T ₁ , and the distance between the end of the pipe and the substrate at the center of the cross section of the opening interface is 12. The field emission electron-emitting device according to claim ₁ , wherein T ₁ <T ₂ <T ₃ , where T ₂ is T ₂ and the substrate temperature is T _3. Method. The method for manufacturing a field emission electron-emitting device according to claim 12, wherein the moisture pressure in the pipe containing the metal compound gas is less than 200 Pa. The method for producing a field emission electron-emitting device according to claim 12 or 13, wherein the metal compound is at least one of a metal complex containing β-diketone as a ligand, a metal alkoxide, and an alkyl metal. A light-emitting device having the field emission type electron-emitting device according to claim 1.

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