KR20070017867A - Electron emission device and a fabrication method for thereof - Google Patents

Abstract

The present invention relates to an electron-emitting device and a method of manufacturing the same. According to an aspect of the present invention, there is provided an electron emitting device comprising: a cathode electrode formed in an island shape by depositing a conductive material on a substrate; A resistance layer formed using a same material as that of the cathode electrode in a predetermined area so as to be connected to the cathode electrode; An insulating layer and a gate electrode having holes formed to sequentially expose a portion of the cathode electrode on the resultant product; And an electron emission unit formed in the exposed region of the cathode electrode.

According to the present invention, the electron-emitting device and the method of manufacturing the same may reduce the process step by simultaneously forming the resistive layer in a predetermined pattern using the same material as the cathode electrode.

Resistive layer, cathode electrode

Description

ELECTRON EMISSION DEVICE AND A FABRICATION METHOD FOR THEREOF

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

2 is a plan view of a first embodiment schematically showing the structure of an electron emitting device according to the present invention;

3 is a cross-sectional view taken along line II ′ of FIG. 2.

4A-4C are flowcharts of a process for one embodiment of a method of manufacturing an electron emitting device according to the present invention.

5 is a plan view showing a second embodiment of an electron-emitting device according to the present invention.

6 is a plan view showing a third embodiment of an electron-emitting device according to the present invention.

<Description of main parts of drawing>

20 --- substrate 21, 51, 61 --- cathode electrode

22 --- First insulation layer 23 --- Gate electrode

24 --- Second Insulation Layer 25 --- Focusing Electrode

26, 56, 66 --- Electron emitter 27 --- Insulated hole

28, 58, 68 --- Resistive layer

The present invention relates to an electron-emitting device and a method of manufacturing the same, and more particularly to an electron-emitting device and a method for manufacturing the same that can reduce the process step by forming a resistive layer in the same pattern using the same material as the cathode electrode.

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.

The MIM and MIS electron emission devices each form an electron emission portion formed of a metal-dielectric layer-metal (MIM) and a metal-dielectric layer-semiconductor (MIS) structure, and are disposed between two metals or metals and semiconductors having a dielectric layer interposed therebetween. When a voltage is applied to the device, a device using the principle of emitting electrons while moving and accelerating from a metal having a high electron potential or a metal having a low electron potential toward the metal.

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 1D 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 and an auxiliary electrode 12 are formed on a substrate 10. The cathode electrode 11 may be formed at a predetermined interval in the form of a pad by depositing a transparent conductor such as indium tin oxide (ITO) on a rear substrate. The auxiliary electrode 12 is patterned by depositing a metal material on the cathode electrode 11.

Thereafter, as illustrated in FIG. 1B, an insulating material is coated on the auxiliary electrode 12 to form a first insulating layer 13, and a conductive metal, for example, is formed on the first insulating layer 13. Chromium (Cr) is deposited by sputtering to form the first gate electrode 14.

In addition, a portion of the cathode electrode 11 formed on the substrate 10 is exposed by coating and patterning photoresist PR on the stacked structure of the first gate electrode 14 and the first insulating layer 13. The first insulating layer 13 and the first gate electrode 14 are etched to form an insulating hole 15a. In this case, the first insulating layer 13 is formed at a predetermined height on the region where the auxiliary electrode 12 is formed.

Thereafter, as shown in FIG. 1C, a second insulating layer 16 and a second gate electrode 17 are formed on the first gate electrode 14. Specifically, at least one selected from a metal having good conductivity on the second insulating layer 16 such as gold (Au), silver (Ag), platinum (Pt), aluminum (Al), chromium (Cr), and alloys thereof. It may be made of a conductive metal material. For example, the second gate electrode 17 is formed by depositing chromium (Cr) to a thickness of about 2,500 kPa to 3,000 kPa by sputtering.

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

Next, as shown in FIG. 1D, a carbon nanotube (CNT) paste is screen printed on the resultant. 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.

On the other hand, the conventional electron emitting device has a structure in which an auxiliary electrode is formed in order to secure a low resistance value of the cathode electrode formed of ITO.

However, the metal material of the auxiliary electrode diffuses into the insulating layer during a predetermined process of the insulating layer, thereby making it difficult to secure the withstand voltage between the cathode electrode and the first gate electrode.

SUMMARY OF THE INVENTION An object of the present invention is to provide an electron emission device capable of reducing a process step by simultaneously forming a resistive layer in a predetermined pattern using the same material as a cathode electrode 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 in an island shape by depositing a conductive material on a substrate; A resistance layer formed using a same material as that of the cathode electrode in a predetermined region so as to be connected to the cathode electrode; An insulating layer and a gate electrode having holes formed to sequentially expose a portion of the cathode electrode on the resultant product; And an electron emission unit formed in the exposed region of the cathode electrode.

In addition, in order to achieve the above object, a method of manufacturing an electron emitting device according to the present invention comprises the steps of depositing a conductive material on a substrate; Simultaneously patterning the conductive material to form a cathode electrode and a resistive layer; Sequentially forming an insulating layer having a hole and a gate electrode to expose a portion of the cathode electrode; And forming an electron emission part in the exposed region of the cathode electrode.

According to the present invention, the process step can be reduced by simultaneously forming the resistive layer in a predetermined pattern using the same material as the cathode electrode.

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 plan view of a first embodiment schematically showing a structure of an electron emission device according to the present invention, and FIG. 3 is a cross-sectional view taken along line II ′ of FIG. 2. 2 and 3, the electron-emitting device according to the present invention, the cathode electrode 21 formed in an island shape by depositing a conductive material on the substrate 20; A resistance layer 28 formed using a same material as that of the cathode electrode 21 in a predetermined region so as to be connected to the cathode electrode 21; A first insulating layer 22 and a gate electrode 23 in which holes are formed to sequentially expose a portion of the cathode electrode 21 on the resultant product; A second insulating layer 24 and a focusing electrode 25 sequentially formed on the gate electrode 23; And an electron emission unit 26 formed in the exposed region of the cathode electrode 21.

The substrate 20 may be, for example, a glass or silicon substrate, and a transparent substrate such as a glass substrate is preferable when the electron emission part 26 is formed by back exposure using a carbon nanotube (CNT) paste. .

The cathode electrode 21 may be formed on the rear substrate at predetermined intervals in the form of an island-shaped 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 resistance layer 28 is formed in a predetermined pattern by using the same metal material as the cathode electrode 21. Here, the resistance layer 28 is formed so that a predetermined number is connected to the peripheral region of the cathode electrode formed in the island shape. In this case, the resistance layer 28 may secure the resistance value of the cathode electrode 21 to prevent distortion of the input signal.

The first insulating layer 22 is formed on the cathode electrode 21 and the resistance layer 28, and electrically insulates the cathode electrode 21 from the gate electrode 23. The first insulating layer 22 may be made of an insulating material, for example, a mixed glass material such as PbO and SiO ₂ .

The 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 the gate electrode 23 is a metal having good conductivity. For example, it may be made of at least one conductive metal material selected from silver (Ag), molybdenum (Mo), aluminum (Al), chromium (Cr), and alloys thereof. The gate electrode 23 is supplied with respective data signals or scan signals applied from the data driver or the scan driver.

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

The focusing electrode 25 is formed on the second insulating layer 24 and is formed of the same metal material as the gate electrode 23. Here, the focusing electrode 25 facilitates the focusing of the electrons emitted from the electron emission part 26.

The electron emission part 26 is electrically connected to the exposed cathode electrode 21 and is positioned on the exposed carbon electrode. Nanotubes by graphite, diamond, diamond-like carbon or a combination thereof; Or a nanowire of Si or SiC.

4A to 4C are flowcharts of a process of an 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 an insulating layer, which will be described later, to a thicker thickness by applying a paste-like insulating material by screen printing. The thin film process is an insulating film such as a silicon oxide film in a chemical vapor deposition (CVD) method. The process of forming an insulating layer with a thinner thickness by depositing this is called. 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 the advantages and disadvantages opposite to the advantages and disadvantages of the above-described thick film process.

First, as shown in FIG. 4A, the cathode electrode 21 and the resistive layer are 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, the cathode electrode 21 deposits ITO on a substrate 20 to a predetermined thickness, for example, a thickness of 800 kPa to 2,000 kPa, and then patternes the ITO into a predetermined shape, for example, an island shape. At this time, the patterning of the cathode electrode 21 is a method for patterning a well-known material layer such as formation of an etching mask by application, exposure and development of photoresist and etching of the cathode electrode 21 using the etching mask. Can be performed by

In addition, the resistive layer 28 is simultaneously patterned with the cathode electrode 21, and a predetermined number of resistive layers are connected to a peripheral region of the cathode electrode 21 patterned in the island shape. Here, the resistance layer 28 can prevent the distortion of the input signal by securing the resistance value of the cathode electrode 21. At this time, the resistance value of the cathode electrode 21 has a 0.1 kW ~ 1 kW.

Subsequently, as illustrated in FIG. 4B, a first insulating layer 22 is formed on the cathode electrode 21 and the resistance layer 28 to have a predetermined thickness. In the case where the first insulating layer 22 is formed 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. or more to about 15 μm to 20 μm. The first insulating layer 22 having a thickness of about is formed. At this time, the firing temperature may vary depending on the type of insulating material.

In addition, after the photoresist PR is applied to the first insulating layer 22, a portion of the first insulating layer 22 is etched to expose a portion of the cathode electrode 21 to form an insulating hole. (27) will be formed.

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. In this case, the first gate electrode 23 is formed up to the stepped portion 23a on the first insulating layer 22.

Next, a second insulating layer 24 and a focusing electrode 26 are formed on the first gate electrode 23. The second insulating layer 24 may be formed by the same method as the method of forming the first insulating layer 22.

The focusing electrode 25 is formed on the second insulating layer 24. Specifically, a conductive metal on the second insulating layer 24, such as silver (Ag), molybdenum (Mo), aluminum (Al), chromium (Cr), and an alloy thereof, may be sputtered. By vapor deposition to a thickness of approximately 2,500 mV to 3,000 mV to form the focusing electrode 25. Here, the focusing electrode facilitates focusing of electrons emitted from an electron emission unit to be formed later.

In addition, the focusing electrode 25 and the second insulating layer 24 are patterned to form an insulating hole 27. Here, the photoresist PR is coated on the stacked structure and then patterned to form an insulating hole 27 by etching part of the focusing electrode 25 and the second insulating layer 24. That is, the insulating hole 27 is completed by dry or wet etching until the cathode electrode 21 is exposed through the insulating hole 27 of the focusing electrode 25 and the second insulating layer 24.

Next, as shown in FIG. 4C, the electron emission part 26 is formed in the insulating hole 27. First, the 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 surface of the insulating hole 27. 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 unit 26 has a desired height while shrinking simultaneously with firing. The firing temperature may vary depending on the type and components of the CNT paste.

As a result, the electron-emitting device in which the height of the insulating layer on the auxiliary electrode is formed differently can be completed to ensure the withstand voltage.

On the other hand, Figure 5 is a plan view showing a second embodiment of the electron-emitting device according to the present invention. As shown therein, the resistive layer 58 of the electron-emitting device according to the present invention is formed by patterning the 10 resistive layers 58 to be connected to the periphery of the cathode electrode 51. At this time, the resistance value is adjusted according to the line width, length, and number of the resistance layer 58 formed around the cathode electrode 51. Here, a detailed description of the second embodiment will be omitted with reference to the first embodiment.

6 is a plan view showing a third embodiment of an electron-emitting device according to the present invention. As shown therein, the resistive layer 68 of the electron-emitting device according to the present invention is formed in a zigzag pattern having a predetermined width and a predetermined length around the cathode electrode 61. That is, the resistance value is adjusted according to the line width, length, and number of the resistance layers 68 formed around the cathode electrode 61. Here, a detailed description of the second embodiment will be omitted with reference to the first embodiment.

As described in each of the above embodiments, by simultaneously forming the resistive layer in the cathode electrode forming process, the productivity can be reduced by reducing the process, and the uniformity of the pixel and the CNT lifetime can be improved due to the formation of the resistive layer. Can be.

Although the present invention has been described with reference to the embodiments illustrated in the drawings, this is merely exemplary, and it 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 can reduce the process step by forming a resistive layer in a predetermined pattern at the same time using the same material as the cathode electrode.

In addition, the uniformity of the pixel and the CNT lifetime may be improved by forming the resistive layer.

Claims (11)

A cathode electrode formed in an island shape by depositing a conductive material on the substrate; A resistance layer formed using a same material as that of the cathode electrode in a predetermined area so as to be connected to the cathode electrode; An insulating layer and a gate electrode having holes formed to sequentially expose a portion of the cathode electrode on the resultant product; And an electron emission unit formed in the exposed region of the cathode electrode. The method of claim 1, And the resistance layer is formed using ITO, which is a conductive material. The method of claim 1, And the resistive layer is formed by simultaneously patterning the cathode electrode. The method of claim 1, The resistance layer is an electron emission device, characterized in that for adjusting the resistance value by adjusting the line width, length and number. The method of claim 1, The resistance value of the resistance layer is an electron emission device, characterized in that 0.1 ~ 1 ㏀. The method of claim 1, And an insulating layer and a focusing electrode further formed on the gate electrode to have a double gate structure. Depositing a conductive material on the substrate; Simultaneously patterning the conductive material to form a cathode electrode and a resistive layer; Sequentially forming an insulating layer having a hole and a gate electrode to expose a portion of the cathode electrode; And forming an electron emission unit in the exposed region of the cathode electrode. The method of claim 7, wherein And a resistive layer formed in a predetermined region so as to be connected to the cathode electrode. The method of claim 7, wherein The method of manufacturing an electron emission device, characterized in that for controlling the resistance value by adjusting the line width, length and number of the resistance layer. The method of claim 7, wherein The resistance value of the resistive layer is a method of manufacturing an electron emission device, characterized in that 0.1 ~ 1 1. The method of claim 7, wherein And sequentially forming another insulating layer and a focusing electrode on the gate electrode.

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