KR20070001582A - Electron emission device and the fabrication method for thereof - Google Patents

Abstract

An electron emission device and a method for manufacturing the same are provided to satisfy voltage resistance and acid resistance by forming upper and lower insulating layers using the same material. An electron emission device includes cathodes(21) formed by depositing a conductive material on a substrate(20), a first insulating layer(22) formed by applying an insulation material on the cathode which exposes a part of the cathode, a first gate electrode(23) formed on the first insulating layer using a metal material, a second insulating layer(24) formed on the first gate electrode and made of the same material as that of the first insulating layer, a second gate electrode(25) formed on the second insulating layer, and an electron emission part(27) formed on the exposed region of the cathode.

Description

ELECTRON EMISSION DEVICE AND THE FABRICATION METHOD FOR THEREOF

1A to 1C are diagrams sequentially illustrating a manufacturing process of an electron emitting device according to the related art.

2 schematically shows the structure of an electron emitting device according to the invention;

3A to 3F are flow charts of a process for one embodiment of a method of manufacturing an electron emitting device according to the present invention.

<Description of main parts of drawing>

20 --- substrate 21 --- cathode electrode

22 --- First insulation layer 23 --- First gate electrode

24 --- Second Insulation Layer 25 --- Second Gate Electrode

26 --- Hall 27 --- Electron emitting unit

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electron emitting device and a method of manufacturing the same. Particularly, in an electron emitting device having a double gate electrode structure, an electron emitting device capable of satisfying voltage and acid resistance by forming an upper insulating layer and a lower insulating layer using the same insulating material. And to a method for producing the same.

In general, an electron emission display device is a display device including an electron emission device for each pixel. The electron emitting device is a device that emits electrons from the cathode in response to a voltage between the cathode and the gate electrode, and the emitted electrons are accelerated by the anode and collide with the phosphor to emit light. In general, there are two types of electron emitting devices using a hot cathode and a cold cathode as electron sources. The electron-emitting devices using the cold cathode are FEA (Field Emitter Array) type, SCE (Surface Conduction Emitter) type, MIM (Metal-Insulator-Metal) type, MIS (Metal-Insulator-Semiconductor) type, BSE (Ballistic) electron surface emitting) and the like are known.

The FEA type electron emission device uses a low work function or high β function as an electron emission source to emit electrons by electric field in vacuum. In addition, devices using electron emission sources for nanomaterials have been developed.

The SCE type electron emission device is a device in which an electron emission part is formed by providing a conductive thin film between two electrodes disposed to face each other on a substrate and providing a micro crack in the conductive thin film. The device utilizes a principle that electrons are emitted from the electron emission portion, which is the fine gap, by applying a voltage to an electrode to flow a current to the surface of the conductive thin film.

MIM type and MIS type electron emitting devices each form an electron emitting portion composed of a metal-dielectric layer-metal (MIM) and metal-dielectric layer-semiconductor (MIS) structure, and are disposed between two metals or metals and semiconductors with a dielectric layer interposed therebetween It is a device using the principle that electrons are released as they move and accelerate from a metal having a high electron potential or a metal having a low electron potential when a voltage is applied therebetween.

The BSE-type electron emitting device forms an electron supply layer made of a metal or a semiconductor on an ohmic electrode by using the principle that electrons travel without scattering when the size of the semiconductor is reduced to a dimension region smaller than the average free stroke of electrons in the semiconductor. And an insulating layer and a metal thin film formed on the electron supply layer to emit electrons by applying power to the ohmic electrode and the metal thin film.

1A to 1C are diagrams sequentially illustrating a manufacturing process of an electron emitting device according to the related art.

As shown in FIG. 1A, first, a cathode electrode 11, a first insulating layer 12, and a first gate electrode 13 are sequentially stacked on a substrate 11. Here, the first insulating layer 12 is formed of a material of PbO, SiO ₂ and proceeds a predetermined process at a temperature of 570 ℃-600 ℃. In addition, the first gate electrode 13 is deposited by sputtering a conductive metal such as chromium (Cr) to form the first gate electrode 13.

 Next, the formed first gate electrode 13 and the first insulating layer 12 are partially patterned on the substrate 10 by coating and patterning a photoresist PR on the stacked structure. The first insulating layer and the first gate electrode 13 are etched to expose the first opening 14.

Thereafter, as shown in FIG. 2B, a second insulating layer 15 and a second gate electrode 16 are formed on the first gate electrode 13. Specifically, the second insulating layer 15 is formed of an insulating material of SiO ₂ and proceeds a predetermined process at a temperature of 520 ℃-550 ℃. Thereafter, at least one selected from a metal having good conductivity, such as gold (Au), silver (Ag), platinum (Pt), aluminum (Al), chromium (Cr), and an alloy thereof, on the second insulating layer 15. It may be made of a conductive metal material. For example, the second gate electrode 16 is formed by depositing chromium (Cr) to a thickness of about 2,500 kPa to about 3,000 kPa by sputtering.

Here, the patterning of the second gate electrode 16 and the second insulating layer 15 also forms the second opening 17 by the method of patterning the material layer described above. In this case, the second gate electrode 16 and the second insulating layer 15 are dry or wet etched until the cathode electrode 11 is exposed to form the second opening 17.

On the other hand, not performing the first opening 14 and the second opening 17 through a single pattern process may be performed by the first gate electrode 13 and the first gate layer 13 when the baking process of the first insulating layer 12 is performed. The first insulating layer 12 reacts to change the material into which the first gate electrode 13 is not etched. Therefore, it is formed by the above method.

Then, as shown in Figure 1c, the carbon nanotube (CNT; CarbonNano Tube) paste on the resultant is printed by screen printing. UV light is irradiated on the back surface of the substrate 10 to selectively expose the CNT paste. When the photoresist PR is removed using a developer such as acetone, the unexposed CNT paste is also removed while the photoresist PR is removed, and only the CNT paste of the exposed portion remains. ). When the firing process is performed at a predetermined temperature, for example, about 460 ° C., the CNT emitter 18 shrinks simultaneously with firing and has a desired height.

This completes the electron-emitting device having the double gate structure and the first gate electrode 13 formed between the first and second insulating layers 12 and 15.

Meanwhile, in the aforementioned method of manufacturing an electron emitting device, the second gate electrode and the second insulating layer are formed on the first opening formed by patterning the first gate electrode and the first insulating layer. When the firing temperature of the second insulating layer is increased at a predetermined time, the first gate electrode is bent to lower the firing temperature.

However, if the firing temperature of the second insulating layer is lowered, the voltage drop may occur due to incomplete firing, and the cracks inside the hole wall may be generated during the etching process of forming the second opening due to lack of acid resistance characteristics. Is generated.

SUMMARY OF THE INVENTION An object of the present invention is to provide an electron emitting device capable of satisfying breakdown voltage and acid resistance by forming an upper insulating layer and a lower insulating layer of the same insulating material, and a method of manufacturing the same.

In order to achieve the above object, the electron-emitting device according to the present invention comprises: a cathode electrode formed by depositing a conductive material on a substrate; A first insulating layer formed by applying an insulating material having a predetermined firing temperature on the cathode to expose a portion of the cathode; A first gate electrode formed of a metal material on the first insulating layer; A second insulating layer formed of the same insulating material as the first insulating layer on the first gate electrode; A second gate electrode formed of a metal material on the second insulating layer; It is characterized in that it comprises an electron emission portion formed in the partially exposed region of the cathode electrode.

In addition, in order to achieve the above object, the method of manufacturing an electron emitting device according to the present invention comprises the steps of: forming a first insulating layer by forming a cathode electrode on a substrate and then applying an insulating material having a predetermined firing temperature; ; Forming a second insulating layer by forming a first gate electrode on the first insulating layer and then applying the same insulating material as that of the first insulating layer; Forming a second gate electrode on the second insulating layer, and then etching a portion of the second gate electrode and the second insulating layer from the formed result; Etching the first gate electrode and the first insulating layer to expose a portion of the cathode electrode so as to correspond to the etched portions of the second gate electrode and the second insulating layer; It is characterized in that it is carried out including the step of forming an electron emitting portion in the region where the cathode electrode is exposed.

Here, in the electron emitting device having the double gate electrode structure, the upper and lower insulating layers may be formed of the same insulating material to satisfy the breakdown voltage and acid resistance.

Hereinafter, preferred embodiments of the electron emission device according to the present invention will be described in detail with reference to the accompanying drawings.

2 is a view schematically showing the structure of an electron emitting device according to the present invention. As shown in the drawing, the electron-emitting device according to the present invention includes a cathode electrode 21 formed by depositing a conductive material on a substrate 20 and an insulating material having a predetermined firing temperature on the cathode electrode 21. Applying a first insulating layer 22 formed to expose a portion of the cathode electrode 21, the first gate electrode 23 formed of a metallic material on the first insulating layer 22, and the first A second insulating layer 24 formed of the same insulating material as the first insulating layer on the gate electrode 23, a second gate electrode 25 formed of a metal material on the second insulating layer 24, and And an electron emission part 27 formed in the partially exposed region 26 of the cathode electrode 25.

The substrate 20 may be, for example, a glass or silicon substrate. When the substrate 20 is formed by back exposure using a carbon nanotube (CNT) paste as the electron emission unit 27, a transparent substrate such as a glass substrate is preferable. .

The cathode electrode 21 may be formed on the rear substrate at a predetermined interval in the form of a pad. The cathode electrode 21 is supplied with a data signal or a scan signal applied from a data driver or a scan driver. The cathode electrode 21 may be a conductor, and for the same reason as the substrate 20, may be a transparent conductor such as indium tin oxide (ITO).

The first insulating layer 22 is formed on the substrate 20 and the cathode electrode 21, and insulates the cathode electrode 21 and the first gate electrode 23.

In more detail, the first insulating layer 22 may be formed of a mixed glass material having an appropriate ratio of an insulating material, for example, PbO, SiO ₂ , Al ₂ O _3, TiO _2, and B ₂ O ₃ . Here, the firing temperature of the first insulating layer is changed by an appropriate ratio of PbO, SiO ₂ , Al ₂ O ₃ , TiO _2, and B ₂ O ₃ , which are insulating materials. For example, if the insulating material has a ratio of 70% PbO, 24% SiO ₂ , 1% Al ₂ O ₃ , 1.5% TiO ₂ , and 4.5% B ₂ O ₃ , firing at a predetermined temperature of 550 ° C. to 570 ° C. Proceed to temperature.

In addition, the proper ratio of the insulating material having the same firing temperature is 44% for PbO, 11% for SiO ₂ , 0.4% for Al ₂ O ₃ , 2% for TiO ₂ and 4% for B ₂ O _3. The rest may apply an insulating material comprising some other material.

The first gate electrode 23 is disposed on the first insulating layer 22 in a predetermined shape, for example, in a direction crossing the cathode electrode 21 on a stripe, and is applied from a data driver or a scan driver. Each data signal or scan signal is supplied.

The first gate electrode 23 may be made of at least one conductive metal material selected from a metal having good conductivity, such as silver (Ag), molybdenum (Mo), aluminum (Al), chromium (Cr), and alloys thereof. .

The second insulating layer 24 is formed on the first gate electrode 23 and is electrically insulated from the second gate electrode 25. Here, the insulating material of the second insulating layer 24 is formed of the same material as the material of the first insulating layer 22.

For example, PbO, SiO ₂ , Al ₂ O ₃ , TiO ₂ and B ₂ O ₃ , which are made of an insulating material, are made of a mixed glass material, and the firing process is performed at a temperature of 550 ° C. to 570 ° C. during firing.

The second gate electrode 25 is formed on the second insulating layer 24 and is formed of the same metal material as the first gate electrode 23. Here, the second gate electrode 25 serves as a focusing electrode, and facilitates the focusing of electrons emitted from the electron emission part 27.

The electron emission unit 27 is electrically connected to the exposed cathode electrode 21, and is formed of carbon nanotubes; Nanotubes by graphite, diamond, diamond-like carbon or a combination thereof; Or a nanowire of Si or SiC.

3A to 3F are flowcharts of a process of one embodiment of a method of manufacturing an electron emission device according to the present invention.

First, the method of manufacturing an electron emitting device according to the present invention will be described in general. The electron emitting device may be manufactured by a thick film process or a thin film process. The thick film process refers to a process of forming a thicker thickness of the first insulating layer 22 and the second insulating layer 24 to be described later by applying an insulating material in a paste state by screen printing. A process of forming the first insulating layer 22 and the second insulating layer 24 to a thinner thickness by depositing an insulating film such as a silicon oxide film in a chemical vapor deposition (CVD) method. According to the thick film process, a large-area display device can be easily manufactured, and there are advantages of securing mass productivity and low manufacturing cost, while it is difficult to manufacture a fine and highly integrated electron-emitting device. On the other hand, the thin film process has advantages and disadvantages opposite to the advantages and disadvantages of the above-described thick film process.

First, FIG. 3A illustrates a state in which the cathode electrode 21 is formed on the substrate 20. Here, a transparent glass substrate is used as the substrate 20 for backside exposure described later. The cathode electrode 21 is also made of indium tin oxide (ITO), which is a conductive transparent material for the same reason as described above.

Specifically, ITO is deposited on the glass substrate 20 to a predetermined thickness, for example, 800 mm to 2,000 mm, and then patterned into a predetermined shape, for example, a stripe shape. At this time, the patterning of the cathode electrode 21 is a pattern of a well-known material layer, such as the formation of an etching mask by the application, exposure and development of photoresist, and the etching of the cathode electrode 21 using the etching mask. It may be carried out by the method.

Next, as shown in FIG. 3B, the first insulating layer 22 is formed on the entire surface of the cathode electrode 21 and the substrate 20 to have a predetermined thickness. In the case of forming the first insulating layer 22 by a thick film process, the insulating material in a paste state is coated to a predetermined thickness by screen printing and then fired at a temperature of about 550 ° C to 570 ° C to about 10 μm to The first insulating layer 22 having a thickness of about 12 μm is formed.

At this time, the firing temperature may vary depending on the type of the insulating material, for example, PbO, SiO ₂ , Al ₂ O _3, TiO ₂ and B ₂ O _{3 It} may be made of a mixed glass of an appropriate ratio. Here, the firing temperature of the first insulating layer is changed by an appropriate ratio of PbO, SiO ₂ , Al ₂ O ₃ , TiO _2, and B ₂ O ₃ , which are insulating materials, but 70% PbO and 24% SiO _2. , Al ₂ O ₃ is 1%, TiO ₂ is 1.5% and B ₂ O ₃ is an insulating material having a ratio of 4.5%, the firing process is performed at a temperature of 550 ℃ when predetermined.

In addition, the proper ratio of the insulating material having the same firing temperature is 44% for PbO, 11% for SiO ₂ , 0.4% for Al ₂ O ₃ , 2% for TiO ₂ and 4% for B ₂ O _3. The rest can be applied to insulating materials including other materials.

On the other hand, when the first insulating layer 22 is formed by a thin film process, by depositing an insulating film such as a silicon oxide film to a thickness of about 1 μm to 1.5 μm by chemical vapor deposition, the first insulating layer 22. ).

Subsequently, a first gate electrode 23 is formed on the first insulating layer 22. The first gate electrode 23 sputters at least one conductive metal material selected from a conductive metal such as silver (Ag), molybdenum (Mo), aluminum (Al), chromium (Cr), and alloys thereof. To a thickness of approximately 2,500 Å to 3,000 Å.

As shown in FIG. 3C, the second insulating layer 24 and the second gate electrode 25 are sequentially stacked on the first gate electrode 23. The second insulating layer 24 is formed at a firing temperature of 550 ° C to 570 ° C using the same insulating material as the first insulating layer 22 described above.

However, when the second insulating layer 24 is formed by a thick film process, the second insulating layer 24 is formed to have a thickness of about 30 μm to 40 μm, and the second insulating layer 24 is formed by a thin film process. In this case, it is formed to have a thickness of about 1㎛ ~ 1.5㎛.

Subsequently, a second gate electrode 25 is formed on the second insulating layer 24. Specifically, one of conductive metals such as silver (Ag), molybdenum (Mo), aluminum (Al), chromium (Cr) and alloys thereof is sputtered on the second insulating layer 24. The second gate electrode 25 is formed by evaporating to a thickness of about 2,500 mW to 3,000 mW. Here, the second gate electrode 25 serves as a focusing electrode and facilitates the focusing of electrons emitted from an electron emission unit to be formed later.

Next, as shown in FIG. 3D, the hole 26 is formed by patterning the second gate electrode 25 and the second insulating layer 24. Here, the photoresist PR is coated on the stacked structure and patterned to form holes 26 by etching the second gate electrode 25 and a part of the second insulating layer 24.

3E, the first gate electrode 23 and the first insulating layer exposed through the holes 26 of the second gate electrode 25 and the second insulating layer 24 are then exposed. The hole 22 is completed by dry or wet etching the 22 until the cathode electrode 21 is exposed.

Next, as shown in FIG. 3F, the electron emission part 27 is formed in the hole 26. First, photoresist (PR) is applied to the entire surface of the resultant, and then patterned so that the cathode electrode 21 is partially exposed on the bottom of the hole 26. A photosensitive carbon nanotube (CNT) paste is applied to the entire surface of the result by screen printing. The CNT paste is selectively exposed by irradiating ultraviolet (UV) light on the back surface of the substrate 20. At this time, only a portion of the CNT paste exposed by the photoresist (PR) pattern is exposed and cured.

Here, by controlling the exposure amount, the exposure depth of the CNT paste may be adjusted. Thereafter, when the photoresist PR is removed using a developer such as acetone, the unexposed CNT paste is also removed while the photoresist PR is removed, and only the CNT paste of the exposed portion remains. ). Subsequently, when the firing process is performed at a predetermined temperature, for example, a temperature of about 460 ° C., the electron emitting portion 27 has a desired height while shrinking simultaneously with firing. The firing temperature may vary depending on the type and components of the CNT paste. The height of the electron-emitting part 27 is approximately 2 μm to 4 μm when the first and second insulating layers 22 and 24 are formed by a thick film process, and the first and second insulating layers 22 are approximately 2 μm to 4 μm. , 24) is approximately 0.5 µm to 1 µm when formed by a thin film process.

Thus, in the electron-emitting device having the double gate electrode structure, an electron-emitting device capable of satisfying the breakdown voltage and acid resistance is completed.

Although the present invention has been described with reference to the embodiments illustrated in the drawings, this is merely exemplary and will be understood by those skilled in the art that various modifications and equivalent other embodiments are possible. . Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

As described above, the electron-emitting device and its manufacturing method according to the present invention in the electron-emitting device having a double gate electrode structure, the upper and lower insulating layers may be formed of the same insulating material to satisfy the breakdown voltage and acid resistance. .

In addition, holes in the upper and lower insulating layers may be formed through a sequential etching process.

Claims (12)

A cathode electrode formed by depositing a conductive material on the substrate; A first insulating layer formed by applying an insulating material having a predetermined firing temperature on the cathode to expose a portion of the cathode; A first gate electrode formed of a metal material on the first insulating layer; A second insulating layer formed of the same insulating material as the first insulating layer on the first gate electrode; A second gate electrode formed of a metal material on the second insulating layer; And an electron emission unit formed in a portion of the cathode electrode exposed area. The method of claim 1, The first insulating layer and the second insulating layer is an electron emission device, characterized in that the firing temperature proceeds from 550 ℃ to 570 ℃. The method of claim 1, And the first insulating layer and the second insulating layer are insulating materials formed of a mixed glass of PbO, SiO ₂ , Al ₂ O _3, TiO ₂ and B ₂ O _{3 in} an appropriate ratio. The method of claim 3, wherein The first insulating layer and the second insulating layer is an insulating material having a ratio of 70% PbO, 24% SiO ₂ , 1% Al ₂ O ₃ , 1.5% TiO ₂ and 4.5% B ₂ O _3. Electron-emitting device. The method of claim 3, wherein The first insulating layer and the second insulating layer have a ratio of 44% PbO, 11% SiO ₂ , 0.4% Al ₂ O ₃ , 2% TiO ₂ , and 4% B ₂ O ₃ , and the rest further add a predetermined material. An electron emission device comprising an insulating material comprising. Forming a cathode on a substrate and then applying an insulating material having a predetermined firing temperature to form a first insulating layer; Forming a second insulating layer by forming a first gate electrode on the first insulating layer and then applying the same insulating material as that of the first insulating layer; Forming a second gate electrode on the second insulating layer, and then etching a portion of the second gate electrode and the second insulating layer from the formed result; Etching the first gate electrode and the first insulating layer to expose a portion of the cathode electrode so as to correspond to the etched portions of the second gate electrode and the second insulating layer; And forming an electron emission part in an area where the cathode electrode is exposed. The method of claim 6, In the forming of the first insulating layer and the second insulating layer, the firing temperature is 550 ℃ ~ 570 ℃ manufacturing method of an electron emitting device, characterized in that. The method of claim 6, The first insulating layer and the second insulating layer is PbO, SiO ₂ , Al ₂ O _3, TiO ₂ and B ₂ O ₃ A method for manufacturing an electron emitting device, characterized in that formed of a mixed glass of an appropriate ratio. The method of claim 8, The first insulating layer and the second insulating layer has a ratio of 70% PbO, 24% SiO ₂ , 1% Al ₂ O ₃ , 1.5% TiO ₂ and 4.5% B ₂ O ₃ characterized in that Manufacturing method. The method of claim 8, The first insulating layer and the second insulating layer have a ratio of 44% PbO, 11% SiO ₂ , 0.4% Al ₂ O ₃ , 2% TiO ₂ , and 4% B ₂ O ₃ , and the rest further add a predetermined material. Method of manufacturing an electron emitting device comprising a. The method of claim 6, And the second gate electrode focuses an electron beam emitted from the electron emission unit. The method of claim 6, And the holes are sequentially etched from the top to expose the cathode electrode.

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