JP3230432B2 - Field emission device and method of manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a field emission device and a method for manufacturing the same.

[0002]

2. Description of the Related Art An electric field applied to a metal or semiconductor surface is 10
^At about ⁹ [V / m], electrons pass through the barrier due to the tunnel effect, and electrons are emitted in a vacuum even at room temperature. This is called field emission, and a cathode that emits electrons based on this principle is called a field emission cathode (hereinafter referred to as FEC).
It is called).

In recent years, it has become possible to manufacture a surface emission type field emission cathode composed of a micron size field emission cathode by making full use of semiconductor processing technology. A large number of field emission cathodes are formed on a substrate. The device is expected to be an element constituting a flat display device or various electronic devices by irradiating electrons emitted from the respective emitters to a phosphor screen formed on an anode substrate.

FIG. 2 is a diagram showing a configuration example of a cathode substrate and an anode substrate. The cathode substrate 100 includes a cathode 102 made of a metal layer, a resistance layer 103 made of amorphous silicon or the like, an insulating layer (SiO ₂ layer) 104 formed by thermally oxidizing silicon on a substrate 101 made of glass or the like,
Then, a gate 105 made of a metal layer of niobium or the like is sequentially formed by vapor deposition or the like. Further, after a photoresist (not shown) is applied on the gate 105, patterning and etching are performed, and an opening 106 is formed in the gate 105 and the insulating layer 104 as illustrated.

Next, the photoresist is removed and the substrate 10 is removed.
While rotating 1, a release layer (not shown) is deposited by rotating evaporation of aluminum from an oblique direction to the substrate surface. Then, the release layer is selectively deposited only on the surface of the gate 105 without being deposited in the opening 106. Further, when, for example, molybdenum is deposited from above the release layer, the deposited layer is placed on the release layer in the opening 106 opened by etching.
07 accumulate in the form of a cone. Thereafter, the gate 105
Removal of the overlying release and deposition layers by etching yields an FEC with the structure shown.

When the FEC shown in FIG. 1 is manufactured by using the semiconductor integration technology, the distance between the cone-shaped emitter 107 and the gate 105 can be made submicron. By applying a voltage of volt, electrons can be emitted from the emitter 107. When a large number of FECs are integrated on the substrate 101, the pitch between the emitters 107 can be made to be 5 to 10 microns.
It can be provided on a single cathode substrate 100.

On the anode substrate 110, a transparent conductive film 112 made of, for example, ITO is formed on a substrate 111 made of, for example, glass, and a phosphor 113 made of, for example, ZnO, which emits green light. It has been applied. Then, the cathode substrate 100 and the anode substrate 110
Is vacuum sealed while maintaining a gap of, for example, about 200 μm.

As described above, a surface emission type FEC can be manufactured, and it has been proposed that this FEC element be applied to a fluorescent display device, a CRT, an electron microscope, and an electron beam device.

FIG. 3 is a perspective view of such a surface emission type FEC element. In this figure, a cathode 102 is formed on a substrate 101, and a resistance layer 103 is formed on the cathode 102. A cone-shaped emitter 107 is formed on the resistance layer 103. Further, a gate 105 is provided on the cathode 102 via an insulating layer 104, and a tip of a cone-shaped emitter 107 faces a round opening 106 provided in the gate 105.

In the surface emission type FEC thus formed, when a driving voltage VGE of several tens of volts is applied between the gate 105 and the cathode 102, electrons are emitted from the emitter 107 and emitted from the emitter 107. The electrons are separated from each other on the gate 105 and are collected by the conductive film 112 of the anode substrate 110 to which the anode voltage VA is applied. In this case, the conductive film 112 is
By collecting the electrons emitted from 07, the phosphor 113 coated on the conductive film 112 can be excited to emit light.

[0011]

By the way, in such an FEC, various power saving means have been considered. For example, on the cathode substrate 100 side: The distance between the gate 105 and the emitter 107 is reduced. 2. A material having a low work function is used as a material for forming the emitter 107. 3. Reduce the radius of curvature of the emitter. 4. Increase emission emission area. And the like.

For example, in the second means, the emitter 107 is made of molybdenum or the like for the reason of workability and the like. This is because the aspect ratio of molybdenum (the height at which the emitter 107 is deposited / the bottom of the emitter 107) is approximately 1: 1 and is therefore a material suitable for manufacturing the emitter 107. However,
Since molybdenum is not a material having a good work function, it is difficult to realize power saving. Also,
For example, when a material having a low work function other than molybdenum is used, there is a problem that workability deteriorates and it becomes difficult to form the emitter 107 into a predetermined shape.

[0013]

SUMMARY OF THE INVENTION The present invention has been made in order to solve such a problem, a field emission cathode substrate, an anode substrate which is spaced apart from the electric field emission cathode substrate are sealed , Low work function substances Ti, Hf, Z
r, Ba, Cr, Pt, Nb, Au material or
Mix nitrides, carbides, borides and oxides of these materials
The anode substrate formed of a fluorescent material
And the formed phosphor,
The surface of the emitter on the field emission cathode substrate is
A field emission device having a deposited layer made of a substance having a function is formed .

In a method of manufacturing a field emission device comprising a field emission cathode substrate and an anode substrate sealed apart from the field emission cathode substrate, the anode substrate has a low work function material Ti , Hf,
Zr, Ba, Cr, Pt, Nb, Au
Nitrides of these materials, carbides, borides, after forming the phosphor mixed oxide, have rows aging sealed field emission cathode substrate the anode substrate, the electric field
Low work function on the surface of the emitter on the emission cathode substrate
A field emission device is manufactured by forming a deposited layer of quality .

[0015]

Embodiments of the present invention will be described below. FIGS. 1A, 1B, and 1C are schematic diagrams for explaining a manufacturing process of the field emission device of the present embodiment. Cathode substrate 1
, The substrate 2, the cathode 3, the resistance layer 4, the insulating layer 5,
The gate 6, the opening 7, and the emitter 8 are respectively shown in FIG.
Has the same structure as the cathode substrate 100 shown in FIG.
4, the gate 105, the opening 106, and the emitter 107.

In the present invention, a substance having a low work function is mixed in the phosphor 13 applied to the conductive film 12 formed on the anode substrate 10. When the phosphor 13 is patterned on the conductive film 12 by, for example, a slurry method, a surfactant, a photosensitive agent, water, a target fluorescent material, and a substance having a low work function are mixed in the slurry liquid. Examples of the material having a low work function include Ti (3.45 eV) and Hf
(3.53 eV), Zr (3.9 eV), or the like, or nitrides, carbides, borides (including oxides) of these materials.
%Mixed. In addition, Ba, Cr, W, Pt,
Materials such as Nb, Au, Ta and the like, or substances such as nitrides, carbides, borides, oxides and silicides of these materials may be used. 1 (a), 1 (b) and 1 (c) show Zn and T
An example is shown in which the phosphor 13 is patterned by mixing i.

FIG. 1A shows a state in which a phosphor 13 mixed with, for example, Zn and Ti is patterned. Further, a cathode substrate 1 and an anode substrate 10 are imposed, and sealing is performed. This is a state in which an exhaust process has been performed.

In this state, as described earlier with reference to FIG.
When the EC is driven and the aging process is started, FIG.
As shown by the arrow in FIG. 2B, a part of Zn and Ti mixed in the phosphor 13 scatters and selectively adheres to the tip of the emitter 8. When this aging process is performed until the deposition of Zn and Ti on the emitter 8 is completed, as shown in FIG.
The tip of the emitter 8 is coated with Zn and Ti to form a deposited layer 9 having a low work function. this is,
Zn, T charged and scattered to a positive charge in the phosphor 13
This is because contaminants such as i adhere to the tip of the emitter 8 which is set at a negative potential from the anode.

As described above, the deposited layer 9 made of, for example, Zn, Ti, etc. is formed at the tip of the emitter 8 and coated with a material having a low work function, so that the electrons are emitted from the emitter 8 more easily, and the Even with a low cathode voltage and a low gate voltage, sufficient electrons can be supplied to the anode substrate side.

[0020]

As described above, according to the present invention, the phosphor formed on the anode substrate is mixed with a substance having a low work function, such as Zn or Ti, so that the phosphor having such a low work function can be obtained. Aging causes the material to adhere to the tip of the emitter. As a result, sufficient electrons can be obtained on the anode substrate even at a lower cathode voltage and gate voltage than in the conventional case. Therefore, low power consumption of the FEC itself can be realized. In addition, by lowering the drive voltage of the cathode and the gate, the driver cost can be reduced.
There is an advantage that manufacturing cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a field emission device according to an embodiment of the present invention.

FIG. 2 is a sectional view showing a conventional field emission device.

FIG. 3 is a perspective view showing a conventional field emission device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cathode substrate 8 Emitter 9 Deposition layer 10 Anode substrate 13 Phosphor

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H01J 31/12 H01J 1/304 H01J 9/02

Claims (2)

(57) [Claims] 1. A field emission cathode substrate, an anode substrate which is spaced apart from the electric field emission cathode substrate is sealed, the low work function material Ti, Hf, Zr, Ba, Cr, P
t, Nb, Au materials or nitrides of these materials;
From fluorescent materials mixed with carbides, borides and oxides
Fluorescence formed on the formed anode substrate
Comprising a body, a emitter on the field emission cathode substrate Aging
Deposited on the surface of the substrate
Field emission element characterized in that it is. 2. A method for manufacturing a field emission device comprising a field emission cathode substrate and an anode substrate sealed apart from the field emission cathode substrate, wherein the anode substrate has a low work function material Ti. , Hf, Z
r, Ba, Cr, Pt, Nb, Au material or
Nitride of et materials, carbides, borides, after forming the phosphor mixed oxide, subjected to aging in sealed field emission cathode substrate the anode substrate, release the field
Low work function material on the surface of the emitter on the cathode substrate
A method for manufacturing a field emission device, comprising forming a deposition layer comprising :