KR20020032209A - Field emitter of field emission display device having metal island and manufacturing method thereof - Google Patents

Abstract

PURPOSE: A field emitter of an FED(Field Emission Display) device having a metal island and a method for fabricating the same are provided to prevent a damage of a device by restricting high voltage due to electron emission of a strong electric field. CONSTITUTION: A substrate(101) is formed by a material such as a glass or a silicon. A metal island(103) has a rectangular shape. The metal island(103) is formed on a surface of the substrate(101) in matrix. One metal island(103) is arrayed on a center portion of one pixel of a field emitter array. A cathode electrode(102) is formed between the metal islands(103). A resistance layer(104) is formed around one side of the metal island(103) and one side of the cathode electrode(102). A gate insulating layer(105) is formed on the cathode electrode(102) and the resistance layer(104). The metal island(103) is exposed partially by a gate hole. The cathode electrode(102) is exposed partially by a cathode hole. A gate electrode(106) is formed on the gate insulating layer(105). A micro tip(109) is formed on the metal island(103). A focusing electrode(108) is formed on the cathode electrode(102).

Description

Field emitter of field emission display device having a metal island and a method of manufacturing the same

BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to a field emitter of a field emission display device having a metal island and a method of manufacturing the same, and more particularly to a field of a field emission display device (FED), hereinafter referred to as a "field emission display device". In an emitter array (Field Emitter Array), a resistive layer configured to be connected to a micro tip to prevent destruction of the device can be formed between the cathode electrode and the metal island to improve the uniformity of emission current between unit pixels. The present invention relates to a field emitter of a field emission display device having a metal island capable of controlling a current flowing through a micro tip according to the distance between the cathode electrode and the metal island and the resistivity of the resistive layer material.

In general, the field emission display device is made of a metal and uses a property that electrons emitted from the micro tip collide with the fluorescent film of the anode to emit light when a strong electric field is applied to the micro tip.

In particular, the field emitter array, in which a large number of micron-sized electron sources are formed in terms of current density, is an electron source capable of high current density emission of several tens of A / cm 2. It is an excellent display device that combines the advantages of high brightness, wide viewing angle, wide operating temperature and humidity, and the thin, light, and lightness of the input of the liquid crystal display.

Field emitters in thin-film field emitters, first proposed by CA Spindt in 1968, make the micro-tips for electron emission conical, and the gate electrodes for applying voltages to the micro-tips are located very close to several micrometers and dozens of V Emission from the micro tip was possible even at low voltages.

Accordingly, when a voltage of several hundred to several thousand V is constantly applied to the anode, and a voltage of 0 or (-) several tens of V is applied to the micro tip (cathode electrode) and (+) several tens of V is applied to the gate electrode, the gate electrode and the micro tip are applied. Due to the strong electric field of the liver, electrons are released from the micro tip and accelerated to the anode electrode.

However, Joule heat is generated by the high current due to the electron emission by the strong electric field, which causes the micro tip to be destroyed, and further, the device may be destroyed by the electrical short between the gate electrodes.

In order to prevent the destruction of the device, a simple electric circuit was initially used by attaching an electrical resistance to the outside of the gate electrode and the cathode electrode to suppress the overcurrent of the cathode electrode. Although uniformity of the unit pixel of the field emission device can be secured.

In order to solve this problem, a technique of forming a respective resistor in a unit pixel has recently been proposed. By applying a resistive layer having a vertical, horizontal, and vertical / horizontal mixed structure to a field emission device, current limiting and device lifetime are extended. I'm making it.

In another method that does not use a resistive layer, VECTL (Vertical) is a protection circuit that protects the FEA chip from arc discharge by applying a trench structure to the substrate of the cold cathode device as shown in FIG. 3. Using a current limiter (hereinafter referred to as "VECTL"), the trenches are arranged to surround the group with 8 x 8 = 64 electron sources as one group.

At this time, arc discharge is a phenomenon in which ionization of residual gas is congested due to an electron impact, and VECTL is a circuit that detects abnormal cathode current, that is, discharge bulb current, flowing at all stages of the arc discharge and automatically suppresses the current. .

When the discharge bulb current flows in the vicinity of any cathode electrode in the group included in the trench structure, the potential of the conical cathode electrode rises, and as the potential rises, the depletion region becomes a pinch-off state.

On the other hand, in normal operation, the depletion layer is reduced, VECTL becomes low resistance, and the necessary electrons are supplied to the cathode electrode. VECTL acts actively on the arc discharge bulb current in this way, which can reduce the series resistance component during normal operation, and is a protection circuit applied to CRT requiring high frequency operation.

However, in order to apply VECFL, it is necessary to form a structure including the cathode electrode in the trench structure. It is very difficult to form trenches having a width of several micrometers and a depth of several tens of micrometers on the substrate, and the manufacturing process of filling an insulating material in the trench is also very difficult, so that the manufacturing yield of the device is significantly reduced.

SUMMARY OF THE INVENTION The present invention has been made to solve the problems described above, and an object of the present invention is to suppress and control a current so as to prevent the destruction of a device which may be caused by a high current due to a strong electric field electron emission in a field emission display device. In providing a possible field emitter.

It is another object of the present invention to provide a method of manufacturing a field emitter capable of suppressing and controlling a current so as to prevent destruction of a device which may be caused by a high current due to electron emission of a strong electric field in a method of manufacturing a field emission display device. have.

Another object of the present invention will be described in more detail in the configuration and operation to be described later.

1 is a cross-sectional view showing a cross-sectional configuration of a field emitter of a field emission display device having a metal island according to the present invention.

2A to 2G are cross-sectional views illustrating a field emitter manufacturing process of the field emission display device according to the present invention.

3 is a flow chart showing the manufacturing process of Figures 2a to 2g.

Description of the main parts of the drawing

11 substrate 12 cathode electrode (electrode wiring layer)

13 metal island 14 resistance layer

15 gate insulating layer 16 gate electrode

17: sacrificial layer 18: focusing electrode (Focusing Electrode)

19: micro tips

The field emitter of the field emission display device according to the present invention for achieving the above object is a metal island formed on a predetermined portion of the substrate; and a cathode electrode formed at a predetermined distance from the metal island; and the metal A resistance layer formed on both ends of the island and on the cathode electrode to connect the metal island and the cathode electrode, and stacked on the metal island, the cathode electrode, and the resistance layer, and exposing a part surface of the metal island. A gate insulating layer having a gate hole and a cathode hole exposing a portion of the cathode electrode, a gate electrode formed on the gate insulating layer, and a focusing electrode formed on the cathode electrode in the cathode hole; And a micro tip formed on the metal island through the gate hole.

Preferably, the metal island may be formed at a central portion of the substrate, and is spaced apart from the cathode electrode at a distance of 0.1 to 20 μm, and the resistance layer is preferably a silicon thin film coated with impurities such as phosphorus (P). It can be formed as.

The focusing electrode may be formed to have the same kind of material as the micro tip.

In addition, the method of manufacturing a field emitter array of the field emission display device according to the present invention comprises the steps of forming a metal island on a predetermined portion of the substrate; and forming a cathode electrode on the substrate to be spaced a certain distance from the metal island And forming a resistance layer formed on both ends of the metal island and on the cathode electrode to connect the metal island and the cathode electrode, and being laminated on the metal island, the resistance layer, and the cathode electrode. Forming a gate insulating layer having a gate hole exposing a surface and a cathode hole exposing a portion of the cathode electrode; and forming a gate electrode on the gate insulating layer; and on the cathode electrode through the cathode hole Forming a focusing electrode; And forming a micro tip on the metal island through the gate hole.

At this time, the focusing electrode and the micro tip may be formed at the same time, it may be formed of a metal of the same material.

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

1 is a cross-sectional view showing the cross-sectional structure of a field emitter of a field emission display device having a metal island according to the present invention.

Referring to FIG. 1, the substrate 101, the metal island 103, the cathode electrode 102, the resistive layer 104, the gate insulating layer 105, and the gate electrode 106 constituting the field emitter array of the field emission display device are shown. ) And micro tips 108 are well shown.

Specifically, the substrate 101 is a silicon or glass substrate is used, a metal island 103 is formed to have a square shape as a preferred example is formed in a matrix on the surface of the substrate 101 is one metal island 103 One pixel of the field emitter array is placed in the center region.

The cathode electrode 102 is formed between the metal islands 103 formed on the substrate 101, and is spaced apart from the metal islands 103 by a predetermined distance, preferably 0.1 to 20 μm.

The resistance layer 104 is formed to surround one side of the metal island 103 and one side of the cathode electrode 102.

The gate insulating layer 105 is stacked on the cathode electrode 102 and the resistance layer 104 formed on the substrate 101, and has a gate hole 110 exposing a part surface of the metal island 103. The cathode electrode 102 is formed to have a cathode hole 113 exposing a portion of the cathode electrode 102.

The gate electrode 106 is formed on the gate insulating layer 105, and the micro tip 109 is formed on the metal island 103 in the gate hole 110.

The focusing electrode 108 is formed on the cathode electrode 102 in the cathode hole 113.

The action of the field emitter of the field emission display device having the structure as described above is connected between the cathode electrode 102 and the metal island 103 to the resistance layer 104 with the specified resistance value, thereby providing an accurate resistance at the micro tip 109. This connection can improve the uniformity of emission current between unit pixels.

In particular, the distance d between the cathode electrode 102 and the metal wire 103 is adjusted to 0.1 to 20 µm, and the PH ₃ SiH ₄ = 0 to 1% component of the amorphous silicon thin film used as the resistance layer 104. By reacting the gas to dopant (P) to adjust the specific resistance of the thin film to control the current flowing through the micro tip 109 through the resistance between the cathode electrode 102 and the metallic 103.

2A to 2G are cross-sectional views illustrating a method of manufacturing a field emitter of a field emission display device according to the present invention, and FIG. 3 is a flowchart showing steps of the manufacturing method.

Referring to FIG. 2A, a metal film such as Cr, Mo, Nb, W, or the like is deposited on a substrate 101, for example, a silicon or glass substrate, by sputtering or the like to have a thickness of 1000 to 5000 GPa, and then a photolithography process is performed. Patterning is performed in one direction as shown in 2a.

That is, as shown in the cross section of FIG. 2A, a metal island 103 is formed in the center portion of the substrate 101, and is spaced apart from the metal island 103 by a predetermined distance d, for example, 0.1 to 2 μm. The cathode electrode 102 is formed (step S1).

Subsequently, an amorphous silicon thin film doped with impurities (phosphorus) is doped using a mixed gas of PH ₃ / SiH ₄ = 0 to 1% on the entire surface of the substrate 101 on which the metal island 103 and the cathode electrode 102 are formed. After forming, patterning is performed to form a resistance layer 605 connecting the metal island 603b and the cathode electrode 603a (step S2).

In this case, the resistor layer 104 is formed at the intersection of the cathode electrode 102 and the metal island 103 and the gate electrode 106 formed later, as shown in FIG. 2B, and covers both ends of the metal island 103. It is formed to surround the cathode electrode 102.

When the resistive layer 104 is not formed on the upper portion of the metal island 103, the resistive layer 104 is not etched differently from the conventional dry etching process for forming the gate hole 110. 110 is formed.

Referring to FIG. 2C, the gate insulating layer 105 is formed on the entire surface of the substrate 101 on which the resistive layer 104 and the metal island 103 are formed. For example, the gate insulating layer 105 may form a silicon oxide film using plasma chemistry. It deposits by a vapor deposition method, a chemical vapor deposition method, etc. (step S3).

Subsequently, a metal film such as Cr, Mo, Nb, or Ni to be used as the gate electrode 106 is deposited on the insulating layer 105 in a thickness of 1000 to 5000 mm by sputtering or the like (step S4).

Thereafter, as shown in FIG. 2D, the gate hole 110 exposing the upper portion of the metal island 103 and the cathode hole 113 exposing all of the cathode electrode 102 are exposed on the insulating layer 105 using the photolithography process. Mask pattern, for example, a photoresist pattern, is formed.

Subsequently, using the mask pattern as a mask, the gate electrode 106 and the insulating layer 105 are dry-etched until the metal islands 103 are exposed to form a gate hole 110 having a diameter of about 0.1 to 2 μm. At the same time, a cathode hole exposing the cathode electrode is formed (step S5).

When the gate electrode 106 is Cr when the gate hole 110 and the cathode hole 113 are formed, etching is performed by using a reactive ion etching method using Cl 2 / O 2 gas, and the gate insulating layer 105 is silicon oxide film. In the case of etch using a reactive ion etching method using CHF ₃ / O 2 gas.

In particular, the metal islands 103 serve as an etch stopper during etching of the gate insulating layer 105 formed of a silicon oxide layer to form the gate hole 110.

Accordingly, the gate hole 110 having a more accurate cylindrical shape can be formed as compared with the related art, and the present invention vertically forms the sidewall of the gate hole using dry etching when the gate hole 110 is formed.

In this way, the electric field applied to the micro tip 109 formed later can be maximized, and the emission current which maximizes many electron emission efficiency can be obtained.

Next, as shown in FIGS. 2F to 2H, the micro tip 109 is formed in the gate hole 110 using a conventional spin process, and the focusing electrode 108 is preferably used at the same time during the manufacturing process of the micro tip 109. It is formed (step S6).

Usually, the micro tip 109 and the focusing electrode 108 are formed using a metal of Cr, Mo, Nb or W.

The field emission display device formed through the above-described process forms a cathode electrode 102 and a new process of forming a metal island 103 which has not been performed in the past, thereby controlling current and preventing destruction of the device. It is possible to form a structure that can be prevented

As described above, the preferred embodiments of the present invention have been described in detail, but those skilled in the art may change or change the present invention without departing from the spirit and scope of the present invention. It will be appreciated that this can be done.

As described above, the field emitter of the field emission display device according to the present invention connects the cathode electrode and the metal island with a resistance layer so that the correct resistance is connected to the micro tip, thereby easily controlling the current flowing through the micro tip, thereby improving the lifespan of the device. Can be extended and the uniformity of the emission current can be increased.

In addition, the field emitter of the field emission display device of the present invention does not form a resistive layer on the metal island, so that the resistive layer is not damaged as in the prior art, and the manufacturing process can be more easily performed.

In addition, by applying the cluster structure, even if the device is destroyed by an external impact, the device of the other cluster parts except the cluster can operate without being destroyed, so that the life of the device can be expected to be extended.

Claims (10)

A metal island formed on a predetermined portion of the substrate; A cathode electrode spaced apart from the metal island by a predetermined distance; A resistance layer formed on both ends of the metal island and on the cathode electrode to connect the metal island and the cathode electrode; A gate insulating layer and a gate electrode formed on the metal island and the resistive layer and having a gate hole exposing a part surface of the metal island; A gate insulating layer and a gate electrode formed on the metal island and the resistive layer and having a focusing electrode hole exposing a portion of the cathode electrode; A focusing electrode electrically connected to the cathode and formed in the focusing electrode hole; And A field emitter of a field emission display device having a metal island comprising a micro tip formed in the gate hole. The method of claim 1, The field emitter of the field emission display device having the metal island, wherein the predetermined portion where the metal island is formed is a central portion of the region where the pixel is to be formed. The metal island is a field emitter of the field emission device having a metal island, characterized in that spaced apart from the cathode electrode by a distance of 0.1 ~ 20㎛. The method of claim 1, And the resistive layer is formed of an amorphous silicon thin film doped with impurities. The method of claim 1, The focusing electrode is a field emitter of a field emission device having a metal island, characterized in that formed at the same time when the micro tip is formed of a metal having the same type of material as the micro tip. Forming a metal island on a predetermined portion of the substrate and forming a cathode electrode spaced apart from the outside by a predetermined distance; Forming a resistance layer formed on both ends of the metal island and the cathode electrode to connect the metal island and the cathode electrode; Forming a gate insulating layer and a gate electrode formed on the resistive layer and the cathode electrode having a gate hole exposing a part surface of the resistive layer; Forming a gate insulating layer and a gate electrode on the metal island and the resistive layer and having a focusing electrode hole exposing a portion of the cathode electrode; And The electrode is electrically connected to the cathode, and the forming of the focusing electrode in the focusing electrode hole and the forming of the micro tip in the gate hole are simultaneously performed, and the materials of the microtip and the focusing electrode are made of the same metal. Field emitter manufacturing method of a field emission device having a metal island. The method of claim 6, The forming of the gate insulating layer and the gate electrode may include forming an insulating layer and a metal film on the entire surface of the substrate on which the resistance layer is formed, and forming a mask pattern exposing a portion of the upper surface of the metal island on the metal film. And dry etching the metal film and the insulating layer using the mask pattern as a mask and the metal island as an etch stop film, and removing the mask pattern. Method of manufacturing field emitters in emission display devices. The method of claim 6, The metal island is a field emitter manufacturing method of a field emission display device having a metal island, characterized in that formed to be spaced apart from the cathode at a distance of 0.1 ~ 20㎛. The method of claim 6, The resistive layer is a field emitter manufacturing method of a field emission display device having a metal island, characterized in that formed of an amorphous silicon thin film doped with impurities. The method of claim 6, And said metal islands are formed in a central portion of a portion of a substrate where pixels are to be formed.