KR970010990B1 - Eld element and its manufacturing method - Google Patents

Abstract

A method of fabricating an electric field electron emitting device includes the first step of forming at least one cathode electrode and an insulating layer on a bottom glass substrate in the direction of row and forming at least one gate electrode thereon in the direction of column, and etching a predetermined portion of the gate electrode and insulating layer to form at least one hole or cavity, the second step of rotating the sample formed through the first step to allow it to have a slope angle of 75= from its center, and simultaneously, depositing a metal to form a division layer, the third step of forming a pyramid-shape resistor layer whose front is flat on the cathode electrode through the cavity or hole whose diameter was reduced by the second step using the slope deposition identical to the second step, the fourth step of forming a cone-shape electric field emitting cathode tip having extremely narrow diameter using the same method as the third step, and the fifth step of lifting off the division layer and layers placed thereon simultaneously.

Description

Field electron-emitting device and manufacturing method thereof

1 is a cross-sectional view of a field electron emission device according to the present invention.

2 (a) to 2 (e) are cross-sectional views for explaining the manufacturing process of the field electron emission device of FIG.

3 is a cross-sectional view of a conventional field electron emission device.

4 is a diagram for explaining the structure of a display device using the field electron-emitting device of FIG.

The present invention relates to a field emission type electron-emitting device and a method for manufacturing the same. More specifically, the resistance of the cathode tip is prevented by increasing the coupling force of the cathode by using a resistance layer, and also using the resistor layer described above. Therefore, the present invention relates to a structure and a manufacturing method of a plurality of conical cathodes or rows having ultra-fine tip diameters, by which current can flow only within a range of constant values, thereby obtaining uniform luminance.

The field electron-emitting device of the present invention is useful as an electron source in various display devices, light sources, amplifiers, high speed switching devices, sensors, and the like.

As a display device that can replace the cathode ray tube (CRT) of a conventional television receiver, a flat image display device for a wall-mounted television, for example, a liquid crystal display (LCD), a plasma display (PDP), an electric field emission device (FED) The development such as) is actively examined.

The field electron emission device achieves very high luminous efficiency and brightness by integrating the unit pixel necessary for image display, that is, the cathode which is the electron generating source per pixel at about 10 ⁴ to 10 ⁵ Tips / mm ^2, and the power consumption is low. Therefore, it is expected to be a display device which is very suitable for the realization of wall-mounted TV in the future.

A representative structural example of the above-mentioned field electron emitting device is shown in FIG. Reference numeral 31 denotes a substrate having high conductivity due to the doping of impurities at a high concentration, and in the cavity 35 formed in the insulating layer 34 formed on the substrate 31, molybdenum (Mo) as an electron emission portion. The formed cathode 36 is formed. In addition, the cathode 36 is surrounded and deposited on the insulating layer 34 as a gate electrode 38 made of a molybdenum thin film.

According to the field electron-emitting device, for example, the gate electrode 38 is biased with respect to the substrate 31 in the range of several 10V to several 100V, thereby conical cathode 36, tip and gate having ultra fine short diameters. An electric field of about 10 ⁶ V / cm to about 10 ⁷ V / cm is generated between the electrodes 38, and as a result, electron emission of about several hundred mA can be obtained from the tip of the cathode 36.

FIG. 4 shows a schematic perspective view of a conventional display device using such an electric field electron-emitting device as an electron source (see Japanese Patent Laid-Open No. 61-221783).

In FIG. 4, a plurality of cathode electrodes 42 are provided on the lower plate glass 40 along the direction of the row 41, and the conical field emission cathode 46 and the insulating layer are formed on the cathode electrodes 42. As shown in FIG. (44) is provided. In addition, a plurality of gate electrodes 48 are provided on the insulating layer 44 in the direction of the row 45. A cavity or a hole is formed at the position of the gate electrode 48 that faces the conical field emission cathode 46.

On the other hand, the transparent conductive film 52 and the fluorescent substance layer 54 are laminated | stacked and deposited in the beta shape on the surface which opposes the said top glass 50 on the upper plate glass 50, respectively. And the lower plate glass 40 and the upper plate glass 50 comprise the exterior for vacuum machines with the side member which is not shown in figure.

The operation of the display device using the conventional field electron emission device constructed as described above is as follows.

A positive potential is applied to the transparent conductive film 52. In response to the display signal, a predetermined potential difference is applied between the column 41 and the cathode electrode 42 and the gate electrode 48 of the row 45. An appropriate electric field is formed between the gate electrode 48 provided with the potential difference and the conical field emission cathode 46, and electrons are emitted from the tip of the conical shape. The electrons are emitted from a hole or a cavity of the gate electrode 48 and collide with the facing phosphor layer 54. As a result, the phosphor layer 54 is excited and emits light.

By the above operation, an image is displayed in accordance with the display signal.

According to the conventional field electron-emitting device as described above, the formation of a high electric field required for electron emission at the cathode tip by forming the cathode 46 tip diameter of about 10 nm is not a problem, but as a display element. In driving conditions, inconveniences occur as follows.

In other words, when electron emission is induced at the tip of many cathodes, the problem is that the tip of the cathode is destroyed or worn by current concentration at a given cathode and the emission intensity at the tip of the cathode is not constant, so that the luminance is uniform. There is a problem that it does not.

In addition, since the bonding force between the cathode tip and the cathode electrode for inducing electron emission is low, the cathode tip is dropped during driving, which causes a decrease in the manufacturing yield. The main cause of the dropout of the cathode tip is that the etching material penetrates into the contact portion between the cathode and the cathode electrode in the stepwise etching process for manufacturing the field electron emission device.

An object of the present invention is to solve the above-mentioned conventional problems, by using a resistor layer to increase the coupling force of the cathode to prevent the dropping of the cathode tip, and by using the resistor layer of the current of a constant value It is to provide an electric field electron-emitting device that can obtain a uniform emission luminance by flowing only within the range.

Another object of the present invention is to provide a field electron-emitting device having at least one cathode formed by the manufacturing process of the present invention for uniform electron emission at the cathode tip.

In order to achieve the above object, there is provided a method of manufacturing the field electron-emitting device according to the present invention, comprising: at least one cathode electrode, an insulating layer, and at least one gate electrode on the insulating layer, in accordance with the direction of the column on the lower plate glass; After sequentially stacking, the first step of forming at least one hole or cavity by photo etching the gate electrode and a predetermined portion of the insulating layer, the inclination angle of about 75 ° around the central axis of the sample formed through the first step The second step of forming a split layer by electron-beam evaporation of a metal while rotating so as to have a cathode, and a gradient deposition method such as a second process through a cavity or a hole having a smaller aperture through the second process, a cathode A third step of forming a pyramidal resistor layer having a planar tip on the electrode, and a resistor formed in the cavity through the third step A fourth process for forming a conical tip having a diameter of about several tens of nm in the same manner as the third process on top of the layer, and the agent for simultaneously lifting off the layers on the top including the divided layer; It is characterized by consisting of five processes.

Another feature of this invention is to include at least one field electron emission cathode structure formed through the above-described manufacturing process for uniform electron emission.

In addition, the electron-emitting cathode structure of the present invention is formed of a pyramidal resistor layer having a bottom end thereof with a planar tip, and a tip end thereof is formed with a conical cathode tip.

In addition, the resistor layer is a material required for improving the bonding strength with the cathode tip, for example, characterized in that made of any one of SiO ₂ , In ₂ O ₃ or SnO ₂ .

Hereinafter, the most preferred embodiments of the present invention will be described with reference to the accompanying drawings so that those skilled in the art can easily implement the present invention.

1 is a cross-sectional view of the field electron-emitting device according to the present invention, a process cross-sectional view for manufacturing the device of FIGS. 2a to 2e or 1, the same parts are denoted by the same reference numerals in order to avoid duplication of description of the drawings. Given.

In FIG. 1, a plurality of cathode electrodes 12 are formed on the lower plate glass 10 in the row direction, and the electron emission cathode 16 and the insulating layer 14 are formed on the cathode electrodes 12. ) Is formed. In addition, a plurality of gate electrodes 18 are formed on the insulating layer 14 in the direction of a row, and the cavity 15 is positioned at a position facing the gate electrode 18 and the cathode 16. Or a hole is formed.

In this case, the electron-emitting cathode 16 has a multilayer structure of different components from the lower end and the upper end, rather than a single layer composed of a single component. The multilayer cathode structure will be described later.

Figures 2a to 2e show the most preferred embodiment for producing the multilayer cathode structure of this invention.

FIG. 2A shows a first process of forming a hole or cavity 15 in a sample in which the cathode electrode 12, the insulating layer 14, and the gate electrode 18 are sequentially stacked on the lower glass 10. FIG. .

The cathode electrode 12 is formed of a line electrode group having a pattern having a line width of about 200 μm and a line interval of about 100 μm according to a row direction on the lower glass 10, and the components thereof include aluminum (Al) and chromium ( A metal such as Cr) or molybdenum (Mo) is deposited to have a thickness of 2000 to 4000 mm 3.

In addition, the insulating layer 14 is deposited by using an electron-beam evaporator or sputtering apparatus commonly used in semiconductor manufacturing so that SiO ₂ has a thickness of 1 μm to 1.5 μm. The distance between the gate electrode 18 and the cathode electrode 12 is determined according to the thickness value of the insulating layer 12, and affects the height setting of the cathode tip. The gate electrode 18 is formed by depositing a metal such as molybdenum (Mo), tungsten (W), or niobium (Nb) to a thickness of about 4000 kPa. Further, the hole 15 is formed by a photolithography technique, for example, set up in a group including anisotropic etching, isotropic etching, reactive ion etching, plasma etching or wet etching so as to appear in the profile shown in FIG. 1a. It is selectively etched using an etching technique.

FIG. 2B shows a partition layer formed by tilting and depositing nickel (Ni) or aluminum (Al) on the surface of the gate electrode 18 while rotating the sample formed through the first process to have a tilt angle of about 75 ° around the central axis. 2nd process of forming (22) is shown. The dividing layer 22 formed through the second process can finely form the diameter of the cathode tip to be formed in the later process by several tens of nanometers (nm) by adjusting the aperture of the hole 15. Again, electron-beam deposition techniques are used.

In the third process, a pyramidal resistor layer 24 having a planar tip is formed on the cathode electrode 12 by the same deposition process as the second process through the hole 15 having a smaller aperture through the second process. It is a process of forming (FIG. 2C). In this case, the barrier layer 24 ′ formed on the division layer 22 simultaneously with the resistor layer 24 is formed at the same height as the resistor layer 24, and the resistor layer 24 is formed of SiO ₂ , In _2. O ₃ or SnO ₂ is also electron-beam deposited.

The fourth step is to form the cathode tip 26, and in the same manner as the third step, a conical cathode tip 26 having a diameter of about several tens nm is formed on the resistor layer 24 in the hole through the hole 15. (Fig. 2d). The material forming the cathode tip 26 is molybdenum (Mo) or tungsten (W), the diameter is about 20 ~ 50nm. At this time, the sharpening of the cathode tip 26 is formed when the barrier layer 26 'is completely covered.

Finally, FIG. 2E shows a fifth process with the partition layer 22 and the barrier layers 24 'and 26' thereon removed. The layers 22, 24 ', 26' are simultaneously removed through a conventional lift-off process.

On the other hand, as shown in FIG. 4, the transparent glass and the phosphor layer are laminated and deposited in beta shape on the surface facing the lower glass 10, as shown in FIG. In addition, the lower glass and the upper glass constitute the outside of the vacuum chamber at the same time as the side member (not shown).

Incidentally, briefly looking at the manufacturing process of the upper glass, a transparent conductive film, which is an anode electrode to which a positive potential is applied, is sputter-deposited on the upper glass. Subsequently, a phosphor layer (ZnO: Zn) is applied by a screen printing method or a slurry method for thick film formation to form a phosphor layer. In this case, when the application field is a color display, green phosphors (Zn _0.65 Cd _0.35 S: Ag, Cl), yellow phosphors (Zn _0.2 Cd _0.8 S: Ag, Cl), and blue phosphors (ZnS: Ag, Cl) are respectively used. use.

The side member is formed by a thick film screen printing method so that the distance between the surface of the phosphor layer and the surface of the gate electrode 18 can be maintained at about 200 μm. Thereafter, the fleet paste is hermetically sealed to the upper and lower plates and the side members, and then heat-fired to melt-seal the flits. The inside of the airtightly sealed panel through the above process is highly vacuumed at 1.0 × 10 ⁶ Torr through an exhaust pipe, and then electrically connected to a drive circuit unit outside the panel, thereby completing the manufacture of the electron emission display device of the present invention.

The operation of the display device manufactured through the above process is as follows.

In response to the display signal, a pixel or conical field emission cathode is matrix driven by applying a predetermined potential difference between the cathode electrode group in the column direction and the gate electrode group in the row direction, so that the electrons emitted from the desired pixel face the phosphor layer. By collision light emission, an image corresponding to the display signal is displayed. Here, the potential difference between the gate electrode and the cathode electrode is maintained before and after 80V, and the anode electrode may be applied with a voltage of about 200V to the transparent conductive film.

As described above, according to the present invention, by controlling the current value flowing through the cathode within a certain range, the problem of tip breakage of the cathode due to excessive concentration of current applied to a predetermined portion is solved, thereby ensuring uniformity of luminance and stability of cathode tip. Can be planned. In addition, it is possible to prevent the dropout of the field emission cathode tip by increasing the bonding force of the cathode.

Claims (4)

At least one cathode electrode, an insulating layer, and at least one gate electrode are sequentially stacked on the insulating layer according to the row direction on the lower glass, and then the gate electrode and a predetermined portion of the insulating layer are etched. The first step of forming at least one hole or cavity, and rotating the sample formed through the first step to have an inclination angle of about 75 ° from the central axis, and simultaneously depositing a metal by electron-beam deposition. A third step of forming a pyramidal resistor layer having a planar tip on the cathode electrode by a gradient deposition method similar to the second step through a second step of forming and a cavity or hole having a smaller diameter through the second step; A conical shape having an ultra-fine diameter in the same manner as the third process on the upper portion of the resistor layer formed in the cavity through the process and the third process; And a fourth step of forming a system emission cathode tip, and a fifth step of simultaneously lifting-off layers including the division layer thereon. The method of claim 1, wherein the resistor layer is made of SiO ₂ , In ₂ O _3, or SnO ₂ . And a cathode electrode group formed on the bottom glass in the direction of the column, a plurality of cathodes and insulating layers formed on the cathode electrode group, and a gate electrode group formed on the insulating layer in the row direction. The field emission cathode according to claim 1, wherein the field emission cathode is formed of a paramid-shaped resistor layer having a planar tip at its lower end, and an upper end thereof is a conical cathode tip. 4. The field electron emission device of claim 3, wherein the resistor layer is made of any one of SiO ₂ , In ₂ O _3, and SnO ₂ .