KR20070036929A - Electron emission device, manufacturing method of the device, and electron emission display device with the same - Google Patents

Abstract

The present invention relates to an electron emission device for forming an electron emission portion by growing a carbon-based material on a catalyst metal layer, and a method for manufacturing the electron emission device according to the present invention includes cathode electrodes and a first insulating layer on a substrate; The gate electrodes and the second insulating layer are sequentially formed, and openings are formed in the second insulating layer and the gate electrodes and the first insulating layer to expose a part of the surface of the cathode electrodes, and a metal layer is formed over the entire surface of the structure provided on the substrate. And forming a catalyst metal layer at a location where an electron emission region is formed on the metal layer, growing a carbonaceous material on the catalyst metal layers to form electron emission regions, and forming a metal layer in the remaining portions except the lower portion of the catalyst metal layer and the upper portion of the second insulating layer. Removing together with the carbon residue deposited on the metal layer in the electron emission forming step.

Electron emission unit, cathode electrode, gate electrode, focusing electrode, insulation layer, catalyst metal layer, catalyst buffer layer, direct growth

Description

ELECTRON EMISSION DEVICE, MANUFACTURING METHOD OF THE DEVICE, AND ELECTRON EMISSION DISPLAY DEVICE WITH THE SAME

1A to 1D are partial cross-sectional views at each manufacturing step shown to illustrate a method of manufacturing an electron emitting device according to an embodiment of the present invention.

2 is a partially exploded perspective view of an electron emission display device according to an exemplary embodiment.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electron emission device, and more particularly, to an electron emission device for forming an electron emission portion by growing a carbon-based material on a catalyst metal layer, a method for manufacturing the same, and an electron emission display device using the electron emission device.

In general, electron emission elements may be classified into a method using a hot cathode and a cold cathode according to the type of electron source.

Here, the electron-emitting device using the cold cathode is a field emitter array (FEA) type, a surface conduction emission type (SCE) type, a metal-insulation layer-metal Metal (MIM) type and Metal-Insulator-Semiconductor (MIS) type are known.

Among them, the FEA type electron emission device includes an electron emission portion and a driving electrode for controlling electron emission of the electron emission portion, and includes one cathode electrode and one gate electrode, and a work function is formed as a constituent material of the electron emission portion. Low or high aspect ratio materials are used to facilitate the release of electrons by an electric field in vacuum.

On the other hand, the electron-emitting device is formed in an array on one substrate to form an electron emission device, the electron-emitting device is combined with another substrate having a light emitting unit consisting of a fluorescent layer, an anode electrode, etc. An emission display device is configured.

That is, the conventional electron emitting device includes a plurality of driving electrodes that function as scan electrodes and data electrodes in addition to the electron emitting part, thereby controlling the on / off and electron emission amount of electron emission for each pixel by the action of the electron emitting part and the driving electrodes. To control. In addition, the electron emission display device excites the fluorescent layer with electrons emitted from the electron emission unit to perform a predetermined light emission or display function.

Recently, in the field of FEA type electron emission devices, a technology for forming an electron emission unit using a carbon-based material which emits electrons well even at low voltage conditions has been researched and developed. Suitable carbon-based materials for electron emission include carbon nanotubes, graphite, and diamond-like carbon. Especially, carbon nanotubes have a radius of curvature of 100? It is expected to be an ideal electron emission material as it is extremely fine and emits electrons well even at a low electric field of 1 to 10 V / µm.

One method of manufacturing the electron emission unit using the carbon-based material is a direct growth method. Direct growth methods include electric discharge, laser deposition, plasma chemical vapor deposition, and thermal chemical vapor deposition. These methods mainly grow carbon-based materials on a catalytic metal layer to obtain electron emission portions.

In the method of manufacturing an electron emission device using the direct growth method, a cathode electrode and a catalyst metal layer are formed on a substrate, an insulation layer and a gate electrode are formed thereon, and an opening is formed in the gate electrode and the insulation layer to expose the catalyst metal layer. And growing a carbonaceous material on the exposed catalytic metal layer to form an electron emission portion.

However, in the process of growing a carbon-based material on the catalyst metal layer, carbon residues are present at unintended portions, that is, sidewalls of the openings of the insulating layer. Since the carbon residue is conductive, it degrades the breakdown voltage characteristics of the cathode electrode and the gate electrode and, in severe cases, may cause a short between the two electrodes.

This problem occurs equally when the FEA type electron emission device has a focusing electrode on the gate electrodes. In this case, an additional insulating layer is positioned between the gate electrodes and the focusing electrode, and an opening corresponding to the opening is also provided in the additional insulating layer and the focusing electrode. In this case, the above-described carbon residues also exist on the sidewalls of the openings of the additional insulating layer, thereby degrading the breakdown voltage characteristics of the gate electrode and the focusing electrode.

Meanwhile, as described above, the FEA type electron emission device including the focusing electrode separately forms the cathode electrodes, the catalyst metal layer, the gate electrodes, and the focusing electrode through respective deposition and patterning processes, thereby making the manufacturing process complicated. I have a problem.

Accordingly, an object of the present invention is to solve the above problems, and an object of the present invention is to provide an electron-emitting device and a method of manufacturing the same, which can increase the breakdown voltage characteristics and simplify the manufacturing process by not leaving carbon residues at unintended sites. The present invention provides an electron emission display device using the electron emission device.

In order to achieve the above object, the present invention,

Maintains insulation with the substrate, cathode electrodes formed on the substrate, a catalyst buffer layer and a catalyst metal layer stacked on the cathode electrodes, electron emission portions made of carbon-based materials grown on the catalyst metal layer, and cathode electrodes And a gate electrode and a focusing electrode positioned above the cathode electrodes and having respective openings for opening the electron emission portions, wherein the catalyst buffer layer and the focusing electrode are made of the same material.

The electron emission unit may include any one material selected from the group consisting of carbon nanotubes, graphite, graphite nanofibers, diamond-like carbon, and C ₆₀ .

The catalyst buffer layer may have an undercut formed at an edge thereof to have a width smaller than that of the catalyst metal layer. The catalyst buffer layer and the catalyst metal layer may be formed of metal materials etched by different etchant.

In addition, the present invention, in order to achieve the above object,

A first substrate and a second substrate disposed opposite to each other, cathode electrodes formed on the first substrate, a catalyst buffer layer and a catalyst metal layer stacked on the cathode electrodes, and carbon-based materials grown on the catalyst metal layer Gate electrodes and focusing electrodes disposed on the cathode electrodes to maintain the electron emitters, the insulating electrodes are insulated from the cathode electrodes, and the fluorescent layers formed on one surface of the second substrate. And an anode electrode formed on one surface of the fluorescent layers, and the catalyst buffer layer and the focusing electrode are made of the same material.

In addition, the present invention, in order to achieve the above object,

Cathode electrodes, the first insulating layer, the gate electrodes, and the second insulating layer are sequentially formed on the substrate, and openings are formed in the second insulating layer, the gate electrodes, and the first insulating layer to expose a portion of the surface of the cathode electrodes. A metal layer is formed over the entire surface of the structure provided on the substrate, the catalyst metal layers are formed at the electron emission formation position on the metal layer, and the carbon-based material is grown on the catalyst metal layers to form electron emission portions, A method of manufacturing an electron emitting device is provided that includes removing a portion of the metal layer other than the top of the second insulating layer together with the carbon residue deposited on the metal layer in the previous electron emission forming step.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1A to 1D are partial cross-sectional views at each manufacturing step shown to illustrate a method of manufacturing an electron emitting device according to an embodiment of the present invention.

First, referring to FIG. 1A, a conductive film is formed on a substrate 10 and patterned to form stripe cathode electrodes 12, and an insulating material is formed on the entire substrate 10 over the cathode electrodes 12. The first insulating layer 14 is formed by deposition or screen printing. A conductive film is formed on the first insulating layer 14 and patterned to form the gate electrodes 16 having a strip shape intersecting with the cathode electrodes 12.

The second insulating layer 18 is formed by chemical vapor deposition or screen printing an insulating material on the entire substrate 10 over the gate electrodes 16. In addition, the surface of the cathode electrodes 12 may be exposed by partially etching the second insulating layer 18, the gate electrodes 16, and the first insulating layer 14 to sequentially form the openings 20.

Next, referring to FIG. 1B, the metal layer 22 is formed by coating a metal material on the entire surface of the structure provided on the substrate 10. Then, the catalyst metal is coated on the surface of the metal layer 22 by thermal vapor deposition or sputtering, and then the coating film is patterned to selectively form the catalyst metal layer 24 at the electron emission region formation position on the cathode electrodes 12.

The catalytic metal layer 24 may be formed of iron (Fe), nickel (Ni), cobalt (Co), or an alloy of these three metals. The metal layer 22 is formed of a material which is etched by the catalyst metal layer 24 and different etchant and is not patterned together in the process of patterning the catalyst metal layer 24. The metal layer 22 has excellent conductivity, for example, molybdenum (Mo) and aluminum. (Al), silver (Ag), or chromium (Cr).

Subsequently, the carbonaceous material on the catalyst metal layer 24 as shown in FIG. 1C by using any one of a direct growth method, i.e., known electric discharge method, laser deposition method, plasma chemical vapor deposition method and thermal chemical vapor deposition method, The carbon nanotubes are grown to form the electron emission unit 26. Carbon-based materials that can be synthesized using the direct growth method include graphite, graphite nanofibers, diamond-like carbon, and C _{60 in} addition to carbon nanotubes.

In particular, the direct growth method which can be effectively applied in this embodiment includes a plasma chemical vapor deposition method and a thermal chemical vapor deposition method. Plasma chemical vapor deposition has the advantage of synthesizing carbon-based materials below 550 ° C, which is the deformation temperature of soda-lime glass, which is mainly used as a substrate for electron-emitting devices, and thermal chemical vapor deposition is used to synthesize high-purity carbon-based materials. Suitable and easy to control microstructure, simple device and advantageous for mass synthesis.

In the case where the plasma chemical vapor deposition method and the thermal chemical vapor deposition method are applied, the surface of the catalyst metal layer 24 is etched using ammonia gas, hydrogen gas, or the like before synthesizing a carbonaceous material on the catalyst layer metal layer 24. To form nanometer-sized fine catalytic metal particles on the surface. This is because carbon-based materials are synthesized on these fine catalytic metal particles.

The plasma chemical vapor deposition process is to generate a glow discharge within the chamber or reaction by direct current or high frequency power applied to the electrodes sikimyeo synthetic carbon-based materials from the fine metal particles in the catalyst layer, as the reaction gas C ₂ H _2, CH ₄ , C ₂ H ₄ , C ₂ H ₆ , or CO gas is used. In the thermal chemical vapor deposition method, a substrate 10 is installed in a quartz reaction tube in which a heating coil is installed, and a carbon-based material is synthesized from the fine metal particles of the catalyst metal layer 24 by flowing a reaction gas into the quartz reaction tube. .

As such, the carbon-based material is synthesized from the catalyst metal layer 24 using the direct growth method to form the electron emission part 26. In this process, an unintended carbon residue is produced, which is deposited to an arbitrary thickness on the surface of the metal layer 22 on the sidewall of the opening 20. In the figure, reference numeral 28 denotes a carbon residue.

Next, the remaining portion of the metal layer 22 except for the lower portion of the catalyst metal layer 24 and the upper portion of the second insulating layer 18 is peeled off to remove the portion of the metal layer 22 and the carbon residue 28 stacked thereon. . Then, as shown in FIG. 1D, the metal layer remaining under the catalyst metal layer 24 becomes the catalyst buffer layer 30, and the metal layer remaining on the second insulating layer 18 becomes the focusing electrode 32.

When the metal layer 22 is peeled off, a mask layer 34 (see FIG. 1C) is formed over the metal layer 22 on the second insulating layer 18, and the substrate is immersed in the metal layer etchant to mask the layer 34 and the catalyst. A wet etching method for removing a portion of the metal layer 22 that is not covered by the metal layer 24 may be applied. At this time, the catalyst metal layer 24 serves as a mask layer so that the catalyst buffer layer 30 is formed thereunder.

In addition, when the metal layer 22 is removed by a wet etching method, it may be overetched to generate a so-called under-cut under the edge of the catalyst metal layer 24. In Fig. 1D, reference numeral 36 denotes an undercut generation site. As described above, the catalyst buffer layer 30 and the focusing electrode 32 may be simultaneously formed while removing the carbon residue 28 through the patterning process of the metal layer 22.

As described above, according to the manufacturing method of the present embodiment, the carbon residue 28 generated in the process of synthesizing the carbonaceous material on the catalyst metal layer 24 is removed together with the carbon residue 28 by the metal layer 22 being removed. Due to the deterioration of the breakdown voltage characteristic, it is possible to simplify the manufacturing process by simultaneously forming the catalyst metal layer 30 and the focusing electrode 32 in one patterning process.

2 is a partially exploded perspective view of an electron emission display device according to an exemplary embodiment.

Referring to the drawings, the electron emission display device includes a first substrate 10 and a second substrate 38 which are disposed to face each other in parallel at predetermined intervals. Sealing members (not shown) are disposed at the edges of the first substrate 10 and the second substrate 38 to bond the two substrates, and the internal space is evacuated with a vacuum of approximately 10 ⁻⁶ torr so that the first substrate 10 ), The second substrate 38 and the sealing member constitute a vacuum container.

On the opposite surface of the first substrate 10 to the second substrate 38, electron emission elements are arranged in an array to form the electron emission device 100 together with the first substrate 10, and the electron emission device ( 100 is combined with the second substrate 38 and the light emitting unit 110 provided on the second substrate 38 to form an electron emission display device.

First, the cathode electrodes 12 and the gate electrodes 16 are formed on the first substrate 10 in a stripe pattern along a direction orthogonal to each other with the first insulating layer 14 therebetween. In the present exemplary embodiment, when the intersection area between the cathode electrode 12 and the gate electrode 16 is defined as a pixel area, one or more electron emission parts 26 are formed in each pixel area over the cathode electrode 12.

The electron emission unit 26 may be formed of a carbon-based material, and may be formed of carbon nanotubes, graphite, graphite nanofibers, diamond-like carbon, C _60, or the like. The electron emission part 26 is formed on the catalyst metal layer 24, and a catalyst buffer layer 30 is formed between the cathode electrode 12 and the catalyst metal layer 24 to electrically connect them.

The catalyst buffer layer 30 has an undercut formed at an edge thereof to have a width smaller than that of the catalyst metal layer 24, and has a selective etching characteristic that is etched by the catalyst metal layer 24 and a different etchant. The catalytic metal layer 24 may be made of iron (Fe), nickel (Ni), cobalt (Co), or an alloy of three metals.

The second insulating layer 18 and the focusing electrode 32 are formed on the gate electrode 16 and the first insulating layer 14. In this embodiment, the focusing electrode 32 may be made of the same material as the catalyst buffer layer 30 and may be formed of, for example, molybdenum (Mo), aluminum (Al), silver (Ag), or chromium (Cr).

The focusing electrode 32, the second insulating layer 18, the gate electrode 16, and the first insulating layer 14 may have an opening 20 for exposing the electron emission part 26 on the first substrate 10. To form. In the drawing, for example, the opening 201 formed in the focusing electrode 32 and the second insulating layer 18 surrounds the three openings 202 formed in the gate electrode 16 and the first insulating layer 14. Shown.

Next, on one surface of the second substrate 38 facing the first substrate 10, the fluorescent layer 40, for example, red, green, and blue fluorescent layers are formed at random intervals from each other, each fluorescent A black layer 42 is formed between the layers 40 to improve the contrast of the screen. An anode electrode 44 formed of a metal film such as aluminum (Al) is formed on the fluorescent layer 40 and the black layer 42.

The anode 44 receives the high voltage necessary for accelerating the electron beam from the outside to maintain the fluorescent layer 40 in a high potential state, and visible light emitted toward the first substrate 10 of the visible light emitted from the fluorescent layer 40. Is reflected toward the second substrate 38 to increase the brightness of the screen.

On the other hand, the anode electrode may be made of a transparent conductive film such as indium tin oxide (ITO) rather than a metal film. In this case, the anode electrode is positioned on one surface of the fluorescent layer 40 and the black layer 42 facing the second substrate 38, and may be formed in a plurality of patterns by patterning a predetermined shape. Moreover, the structure which uses simultaneously the above-mentioned transparent conductive film and a metal film as an anode electrode is also possible.

In addition, a plurality of spacers 46 are disposed between the first substrate 10 and the second substrate 38 to support the compressive force applied to the vacuum container and to keep the distance between the two substrates constant. The spacers 46 are positioned corresponding to the black layer 42 so as not to invade the fluorescent layer 40.

The electron emission display device having the above-described configuration is driven by supplying a predetermined voltage to the cathode electrodes 12, the gate electrodes 16, the focusing electrode 32, and the anode electrode 44 from the outside.

For example, any one of the cathode electrodes 12 and the gate electrodes 16 receives a scan driving voltage to serve as scan electrodes, and the other electrodes receive a data driving voltage to serve as data electrodes. The focusing electrode 32 receives a voltage required for electron beam focusing, for example, 0V or a negative DC voltage of several to several tens of volts, and the anode electrode 44 is a voltage required for electron beam acceleration, for example, several hundreds to thousands of volts. DC voltage of is applied.

Then, an electric field is formed around the electron emission part 26 in the pixels in which the voltage difference between the cathode electrode 12 and the gate electrode 16 is greater than or equal to the threshold, and electrons are emitted therefrom. The emitted electrons are focused to the center of the electron beam bundle while passing through the opening 201 of the focusing electrode 32, and are attracted by the high voltage applied to the anode electrode 44 to collide with the fluorescent layer 40 of the corresponding pixel to emit light. Let's do it.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited thereto, and various modifications and changes can be made within the scope of the claims and the detailed description of the invention and the accompanying drawings. Naturally, it belongs to

As such, according to the present invention, even when incidental carbon residues are generated when the carbon-based material is synthesized on the catalyst metal layer to form the electron emission portion, the carbon residues can be effectively removed in the process of patterning the metal layer later. Therefore, it is possible to secure the withstand voltage characteristics of the cathode electrode, the gate electrode and the focusing electrode, and to remove the carbon residue and simultaneously form the catalyst buffer layer and the focusing electrode in one metal layer patterning process, thereby simplifying the manufacturing process. .

Claims (13)

A substrate; Cathode electrodes formed on the substrate; A catalyst buffer layer and a catalyst metal layer stacked on the cathode electrodes; Electron emission portions made of carbon-based materials grown on the catalyst metal layer; A gate electrode and a focusing electrode, which are insulated from the cathode electrodes and positioned above the cathode electrodes, each having a respective opening for opening the electron emission parts; And the catalyst buffer layer and the focusing electrode are made of the same material. The method of claim 1, And the electron emission unit comprises any one material selected from the group consisting of carbon nanotubes, graphite, graphite nanofibers, diamond-like carbon, and C ₆₀ . The method of claim 1, And the catalyst buffer layer has an undercut formed at an edge thereof to have a width smaller than that of the catalyst metal layer. The method of claim 1, And the catalyst buffer layer and the catalyst metal layer are made of a metal material etched by different etchant. The method of claim 1, The catalyst metal layer is made of any one material selected from the group consisting of iron, nickel, cobalt and alloys thereof, And the catalyst buffer layer and the focusing electrode are made of any one material selected from the group consisting of molybdenum, aluminum, silver and chromium. An electron emitting device according to any one of claims 1 to 5; Another substrate disposed to face the substrate; Fluorescent layers formed on one surface of the other substrate; And And an anode electrode formed on one surface of the fluorescent layers. Forming cathode electrodes, first insulating layer, gate electrodes and second insulating layer sequentially on the substrate; Openings are formed in the second insulating layer, the gate electrodes and the first insulating layer to expose a portion of the surface of the cathode electrodes; Forming a metal layer over the entire surface of the structure provided on the substrate; Forming catalyst metal layers on the metal layer at an electron emission region; Growing a carbon-based material on the catalyst metal layers to form electron emission portions; Removing the metal layer of the portions other than the lower portion of the catalyst metal layer and the upper portion of the second insulating layer together with the carbon residue deposited on the metal layer in the electron emission forming step. The method of claim 7, wherein A method of manufacturing an electron emission device using any one of an electric discharge method, a laser deposition method, a plasma chemical vapor deposition method and a thermal chemical vapor deposition method when growing the carbonaceous material. The method of claim 7, wherein When the catalyst metal layer is formed, iron, nickel, cobalt or an alloy thereof is formed by any one of thermal vapor deposition and sputtering, Prior to growing the carbon-based material on the catalyst metal layer, etching the surface of the catalyst metal layer to form nanometer-sized fine catalyst particles. The method of claim 7, wherein And forming a metal material etched by an etchant different from the catalyst metal layer when forming the metal layer. The method of claim 10, A method of manufacturing an electron emitting device, wherein the metal layer is formed of a material of any one of molybdenum, aluminum, silver, and chromium. The method of claim 10, And wet etching using a metal layer etchant when removing a portion of the metal layer. The method of claim 12, Overetching the metal layer to produce an undercut at the edge of the metal layer.

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