KR19990084341A - Field emission emitter and manufacturing method thereof - Google Patents

Abstract

Field of the Invention The present invention relates to a field emission emitter and a method of manufacturing the same, which can obtain a high emission current density even under low voltage using a diamond-like carbon material.

The field emission emitter of the present invention includes an electron emission unit for emitting electrons, an emitter electrode for applying a voltage to the electron emission unit, and a conductor pattern formed at a predetermined height between the electron emission unit and the emitter electrode. .

According to the present invention, it is possible to form a planar diamond-like carbon thin film emitter having high electron emission characteristics even at low voltage, thereby realizing a large area FED capable of driving at low voltage.

Description

Field emission emitter and fabrication methods thereof

BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to a field emission display device, and more particularly, to a planar field emission emitter and a method of manufacturing the same, which can obtain a high emission current density even under low voltage using a diamond-like carbon material.

In recent years, field emission displays (hereinafter referred to as FEDs) are being actively researched for application to next-generation flat panel display devices due to advantages such as excellent display characteristics and manufacturing cost competitiveness. The FED typically displays an image using light generated by colliding electrons emitted from the electron-emitting device with the phosphor. As a field emission element used for such an FED, that is, a field emission emitter, a tip-shaped emitter and an emitter using a flat diamond thin film or diamond-like carbon thin film are mainly used.

However, the tip-shaped emitter has the disadvantage of being chemically unstable while having good field emission efficiency. In other words, as a tip material, a metal that is relatively rigid and easy to manufacture, such as molybdenum (Mo) and silicon (Si), is generally used. These metal materials have disadvantages of being chemically unstable in the tip state. For this reason, a method of implementing an emitter by applying a material such as diamond-like carbon having chemically stable properties on a tip has been attempted. The methods mainly used to manufacture such tip type emitters include a spin method and a method of manufacturing a tip by etching silicon. However, the spin method of the former forms a tip by rotating a substrate or a target, and thus requires a precision in the process, which makes it difficult to apply to large area. In addition, the method of manufacturing the tip by etching the latter silicon is difficult to prepare a large area substrate because it uses a silicon substrate.

Accordingly, a method of implementing an emitter using diamond or diamond-like carbon, in which electron emission occurs at a low applied voltage as well as in a tip state, has been attempted. In particular, since the diamond or diamond-like carbon material is excellent in chemical stability, it has the advantage of maintaining the initial electron emission efficiency more stably.

However, such a diamond or diamond-like carbon is excellent in chemical stability, it is difficult to fine pattern the FED. In other words, diamond and diamond-like carbon have a problem that it is difficult to obtain a desired pattern because of difficulty in etching. Accordingly, in order to facilitate the patterning of diamond and diamond-like carbon, only a desired portion is pretreated with diamond microparticles, etc. before vapor phase chemical vapor deposition, so that only a portion of diamond is selectively formed during deposition. As shown in the drawing, a method of forming a pattern using a kind of mask is used.

Referring to FIG. 1A, the structure in which the emitter electrode 12, the insulating layer pattern 14, and the gate pattern 16 are sequentially stacked on the glass substrate 10 is illustrated. The emitter electrode 12 is formed on the glass substrate 10 by a general coating process. The insulating layer pattern 14 and the gate pattern 16 are formed by sequentially forming an insulating material layer and a gate material layer (ie, a metal layer) on the emitter electrode 12 and then patterning them using a photolithography process. .

An isolation layer 18 is formed on the gate pattern 16 as shown in FIG. 1B. The separation material layer 18 is formed by rotating the glass substrate 10 while using an electron beam.

Referring to FIG. 1C, diamond-like carbon thin films 20a and 20b are formed on the exposed portion of the emitter electrode 12 and the separation layer 18. The diamond-like carbon thin films 20a and 20b are formed on the exposed portion of the emitter electrode 12 and the separation layer 18 by injecting the diamond-like carbon particles by a physical vapor deposition process or the like.

Next, the diamond-like carbon thin film 20b formed thereon together with the separation layer 18 is removed to form a flat diamond-like carbon thin film pattern 20a on the emitter electrode 12 as shown in FIG. 1D. Then, the field emission emitter array having the structure in which the insulating layer pattern 14 and the gate pattern 16 are sequentially stacked on the emitter electrode 12 around the diamond-like carbon thin film pattern 20a is completed.

Here, the diamond-like carbon thin film pattern must have a fine size, that is, a size of several micrometers (μm) in order to emit electrons even in a small electric field. To this end, the gate layer and the insulating layer must be precisely etched in the diamond-like carbon thin film pattern manufacturing method. However, since it is difficult to precisely etch the gate layer and the insulating layer, there is a problem in that a precise and fine diamond-like carbon thin film pattern cannot be obtained. In addition, the diamond-like carbon thin film pattern manufacturing method has a disadvantage in that the diamond-like carbon thin film is formed in unnecessary parts.

Accordingly, an object of the present invention is to provide a field emission emitter capable of fine patterning a diamond-like carbon thin film and a method of manufacturing the same.

Another object of the present invention is to provide a field emission emitter having a low electron emission voltage and stable electron emission efficiency and a method of manufacturing the same.

It is still another object of the present invention to provide a field emission emitter capable of realizing a large area FED and a method of manufacturing the same.

It is still another object of the present invention to provide a field emission emitter and a method of manufacturing the same, which can reduce the manufacturing cost by simplifying the manufacturing process.

1 is a cross-sectional view showing a step of forming a conventional diamond thin film pattern step by step.

2 is a cross-sectional view showing a structure of a field emission display to which a diamond-like carbon emitter is applied according to the present invention.

3 is a graph showing the electric field strength of the emitter shown in FIG. 1 and FIG.

Figure 4 is a cross-sectional view showing a step in manufacturing a diamond-like carbon emitter according to the present invention.

<Brief description of symbols for the main parts of the drawings>

10, 22: lower substrate 12, 24: emitter electrode

14, 26: insulation layer pattern 16, 28: gate pattern

18: separation layer 20a, 20b, 34, 34a: diamond-like carbon thin film

30: first conductor pattern 32: second conductor pattern

36: upper substrate 38: phosphor

40: coating film

In order to achieve the above objects, the field emission emitter according to the present invention includes an electron emission unit for emitting electrons, an emitter electrode for applying a voltage to the electron emission unit, and a predetermined distance between the electron emission unit and the emitter electrode. And a conductor pattern formed at a height.

In addition, the method of manufacturing a field emission emitter according to the present invention includes the first step of forming an emitter electrode on a substrate, the second step of forming a conductor pattern on the emitter electrode, and forming an electron emission part on the conductor pattern. Characterized in that it comprises three steps.

Other objects and advantages of the present invention in addition to the above object will become apparent from the description of the preferred embodiment of the present invention with reference to the accompanying drawings.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to FIGS. 2 to 4.

2 is a cross-sectional view of a FED to which a field emission emitter is applied according to an embodiment of the present invention, in which the FED includes an emitter array formed on a lower glass substrate 22.

In the FED of FIG. 2, the emitter array includes a flat emitter 24 having an emitter electrode 24 disposed on the lower glass substrate 22 and a connecting portion 30 and 32 disposed on the emitter electrode 24. 34 and the insulating layer 26 and the gate 28 of the structure laminated | stacked on the emitter electrode 32 around the planar emitter 34 are comprised. The flat emitter 34 is made of a material having a relatively high electric field strength on its surface, that is, a diamond or diamond-like carbon material to facilitate electron emission even by a low applied voltage. The connecting portions 30 and 32 formed below the flat emitter 34 have a 'T' shape, connecting the flat emitter 34 and the emitter electrode 24 and connecting the flat emitter 34. Will be supported. To this end, the connecting portions 30 and 32 are formed at a predetermined height on the surface of the head 30 having the flat emitter 34 formed on the surface and the emitter electrode 24 to support the head 32. The neck part 32 is comprised. The emitter electrode 24 disposed on the lower glass substrate 22 applies a voltage to the planar emitter 34 through the connecting portions 30 and 32. The gate 28 formed on the emitter electrode 24 with the insulating layer 26 therebetween forms a strong electric field around the planar emitter 34 to allow electrons to be emitted from the planar emitter 34. In other words, the planar emitter 34 emits electrons by the voltage applied between the emitter electrode 24 and the gate 28.

In addition, the FED illustrated in FIG. 2 includes an upper glass substrate 36 disposed at a predetermined distance from the emitter array described above, and a phosphor 38 coated on a bottom surface of the upper glass substrate 36. do. Electrons emitted from the planar emitter 34 described above are accelerated by a voltage applied to an upper electrode (not shown), that is, an anode disposed between the upper glass substrate 36 and the phosphor 38, and thus the phosphor. Light impinges on the phosphor by colliding with (38). An appropriate degree of vacuum is maintained between the emitter array and the phosphor 38.

In this configuration, the flat emitter 34 made of diamond or diamond-like carbon material has a high field strength distributed on the surface as compared with the conventional field emission emitter.

Referring to FIG. 3, the intensity of the field strength distributed over the emitter surface relative to the position r from the center of the field emission emitter is shown. In FIG. 3, curve a indicates the intensity of the electric field strength distributed on the surface of the conventional planar emitter 20b shown in FIG. 1, and curve b shows the plane emitter 34 of the present invention shown in FIG. It displays the strength of the electric field strength distributed on the surface. Here, it can be seen that the intensity of the electric field strength distributed on the surface of the flat emitter 34 according to the present invention is several times larger than that of the conventional flat emitter 20b.

FIG. 4 is a cross-sectional view showing step by step the manufacturing process of the field emission emitter array shown in FIG.

Referring to FIG. 4A, the emitter electrode 24, the first conductor layer 30a, and the second conductor layer 32a, which are sequentially stacked on the lower glass substrate 22, are illustrated. The emitter electrode 24 is formed to have a uniform thickness on the surface of the lower glass substrate 22 by a general coating process such as conventional vapor phase physical vapor deposition, vapor phase chemical vapor deposition, and electroplating. The first and second conductor layers 30a and 32a sequentially stacked on the emitter electrode 24 are also formed by a general coating process. The material of the first conductor layer 30a is preferably metal, and the metal, semiconductor, or the like may be used for the second conductor layer 32a.

Referring to FIG. 4B, the first conductor layer pattern 30 formed on the surface of the emitter electrode 24 and the second conductor layer pattern 32 formed thereon are illustrated. The second conductor layer pattern 32 located thereon is formed by patterning by a photolithography process using an appropriate photoresist pattern. The first conductor layer pattern 30 under the second conductor layer pattern 32 is formed by patterning using the above process. At this time, the first conductor layer pattern 30 is etched inward more than the second conductor layer pattern 32. Accordingly, the first conductor layer pattern 30 and the second conductor layer pattern 32 have a 'T' shape, as shown in FIG. 2, that is, a connecting portion consisting of the head part 32 and the neck part 30. Will be formed.

Referring to FIG. 4C, the coating film 40 coated on the emitter electrode 24 on which the connection portion is formed is shown. The coating film 40 is formed to have a flat surface on the emitter electrode 24 on which the connection portion is formed by a method such as spin coating or vapor chemical vapor deposition.

The coating film 40 is etched to an arbitrary depth so that only the coating film 40a of the appropriate thickness remains on the emitter electrode 24 between the first conductor layer patterns 30 as shown in FIG. 4D.

Referring to FIG. 4E, diamond-like carbon thin films 34a and 34 coated on the coating film 40a between the first conductor layer pattern 30 and the third conductor layer pattern 32 are illustrated. The diamond-like carbon thin films 34a and 34 are formed on the surfaces of the coating film 40a and the first conductor layer pattern 32 by vapor phase physical vapor deposition such as laser ablation, ion beam sputtering, or other methods.

Then, the coating film 40a on the emitter electrode 24 is removed together with the diamond-like carbon thin film 34a formed thereon, so that the diamond-like film formed on the surface of the second conductor layer pattern 32 as shown in FIG. 4F. The thin film of carbon, that is, the field emission emitter array in which the flat emitter 34 is formed, is completed.

Meanwhile, as another embodiment of the present invention, the diamond-like carbon thin films 34a and 34 illustrated in FIG. 4E may be formed by vapor phase chemical vapor deposition. In this case, the surface of the uppermost second conductor layer 32a shown in FIG. 4A may be pretreated or catalyzed using diamond particles to facilitate formation of a diamond-like carbon thin film on the first conductor layer 32a. have. Here, it is preferable to use a metal material which is easy to form a diamond-like thin film such as tungsten (W) or nickel (Ni) as the material of the second conductor layer 32a. Accordingly, when the diamond-like carbon particles are deposited by using the chemical vapor deposition method, the diamond-like carbon thin film 34 is formed only on the surface of the pretreated second conductor layer pattern 32 and the coating film 40a is deposited. And the other part is to form a carbon compound having a poor bonding force. The carbon compound formed at such an unnecessary portion is removed by a physical method such as ultrasonic cleaning and the etching process of the coating film 40a.

As a result, the present invention can provide a field emission emitter having high electron emission characteristics even by a low voltage.

As described above, according to the field emission emitter and the manufacturing method thereof according to the present invention, it is possible to form a flat diamond-like carbon thin film emitter having a high electron emission characteristic even by a low voltage, so that a large area that can be driven at low voltage FED can be implemented. In addition, since the field emission emitter manufacturing method according to the present invention is a generalized etching process and a thin film forming process, the manufacturing process can be simplified as well as the manufacturing cost can be reduced.

Those skilled in the art will appreciate that various changes and modifications can be made without departing from the technical spirit of the present invention. Therefore, the technical scope of the present invention should not be limited to the contents described in the detailed description of the specification but should be defined by the claims.

Claims (15)

An electron emission unit for emitting electrons, An emitter electrode for applying a voltage to the electron emitting unit; And a conductor pattern formed between the electron emission unit and the emitter electrode at a predetermined height. The method of claim 1, A substrate on which the emitter electrode is formed; A gate electrode formed around the electron emission unit and applying a voltage for emitting electrons; And a dielectric layer formed between the emitter electrode and the gate electrode. The method of claim 1, The electron emission unit is a field emission emitter, characterized in that any one of a planar diamond thin film pattern and diamond-like carbon thin film pattern. The method of claim 1, The conductor pattern is A first conductor pattern on which the electron emission unit is formed; And a second conductor pattern formed on the emitter electrode to support the first conductor pattern. The method of claim 4, wherein The material of the second conductor pattern is a field emission emitter, characterized in that the metal material. A first step of forming an emitter electrode on the substrate, Forming a conductor pattern on the emitter electrode; And a three step of forming an electron emission unit on the conductor pattern. The method of claim 6, The second step is Sequentially forming a first conductor layer and a second conductor layer on the emitter electrode; Patterning the second conductor layer using a photolithography process; And etching the first conductor layer deeply inward than the second conductor layer to pattern the first conductor layer. The method of claim 7, wherein The material of the first conductor layer is a field emission emitter, characterized in that the metal material. The method of claim 6, The third step is Applying an optional coating film to have a flat surface on the emitter electrode on which the conductor pattern is formed; Etching the coating layer to have a lower height than the conductor pattern; Forming an electron emission material layer on surfaces of the conductor pattern and the coating film; And removing the coating layer and the electron emission material layer formed on the coating layer. The method of claim 9, The coating film is a field emission emitter manufacturing method characterized in that the coating using any one of a spin coating method and a vapor chemical vapor deposition method. The method of claim 9, The electron-emitting material layer is a field emission emitter manufacturing method, characterized in that formed using the vapor phase physical vapor deposition method. The method of claim 9, The electron-emitting material layer is a field emission emitter manufacturing method characterized in that formed by using a chemical vapor deposition method. The method of claim 12, When using the vapor phase chemical vapor deposition step 2 And forming a surface of the second conductor layer and pretreating the surface thereof. The method of claim 13, The second conductor layer is a field emission emitter manufacturing method, characterized in that made of a metal material that is easy to form the electron emitting portion. The method of claim 6, The electron-emitting material layer is a field emission emitter manufacturing method, characterized in that made of any one of diamond and diamond-like carbon.