JPH04118829A - Electron emission device - Google Patents

Abstract

PURPOSE:To obtain an electron beam of high quality and of high precision by causing an electric field to be concentrated on an edge portion of a cathode material layer and using a first control electrode to cause the electron beam to be so directed as not to advance toward second control electrodes, thereby causing a centrally directing force to be produced. CONSTITUTION:A cathode material layer 2 and first and second control electrodes 5, 7 are connected to a power supply such that the layer 2 is negative and the electrodes 5, 7 are positive. A voltage having a level higher than a prescribed level determined depending upon the cathode material layer 2 is applied between both the electrodes, thereby causing an electric field to be concentrated onto edge portions 4 of the layer 2 and thereby causing electrons to be emitted out into an ambient vacuum zone from the edge portions 4. The electron thus liberated into the vacuum zone has its orbit determined along a line of electric force having a voltage which is determined depending upon the first control electrode 5, second control electrode 7 and cathode material layer 2. Therefore, while no provision of the first control electrode 5 results in the moving of the emitted electron beam toward the second control electrode 7, i.e., spreading or scattering thereof, provision of the first control electrode 5 causes a centrally directing force to be produced toward a center of the electron emission device, namely, suppresses the spreading of the electron beam, thereby enabling increase in quality of the electron beam.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an electron-emitting device that can be used as an electron source for various electron beam application devices such as electron microscopes, electron beam exposure devices, and CRTs. .

2. Description of the Related Art Conventionally, a hot cathode that emits thermoelectrons has been used as an electron generation source in an electron microscope, an electron beam exposure device, a CRT, and the like. However, hot cathodes require heating means to heat the cathode itself, and there are also problems such as energy loss due to heating. Therefore, in recent years, research has been conducted on electron-emitting devices that do not require heating, so-called cold cathodes, and several types of electron-emitting devices have been developed.

For example, an electron-emitting device in which a reverse bias voltage is applied to a PN junction to cause an electron avalanche breakdown phenomenon to emit electrons out of the device, or a three-layer structure consisting of a metal layer, an insulator layer, and a metal layer. , an MIM-type electron-emitting device that emits electrons that have passed through the insulating layer due to a tunnel effect to the outside of the device from the surface of the metal layer by applying a voltage to both metal layers, or a shape that tends to cause electric field concentration. There is a field emission type electron-emitting device, which applies a voltage to a formed metal to locally generate a high-density electric field, and causes the metal to emit electrons to the outside of the device.

Among these electron-emitting devices, in the case of field-emission type devices, the curvature of the tip is made to be less than a few hundred meters so that a strong electric field of about 10 V/(2) is concentrated at the tip of the cathode emitter for electron emission. It is processed into a needle shape.

This field emission type electron-emitting device generally has the following advantages.

(1) High current density.

(2) There is no need to heat the cathode, so power consumption is extremely low.

(3) Can be used as point and line electron beam sources.

As the above-mentioned field emission type electron-emitting device, for example, the one described in Journal of Applied Physics, Vol. 39, No. 7, p. 3504, 1968 (Journal of A
ppliedPhysics, Vol, 39, N00
7, P 3504.1968) K A configuration as described is known. FIG. 6 (al is a cross-sectional view showing the state of the conventional electron-emitting device in the middle of manufacturing, FIG. 6 (b)
FIG. 1 is a cross-sectional view showing a conventional electron-emitting device in a completed state.

As shown in FIG. 6(a), first, an electrically insulating substrate 10
A conductive film 102, an insulating layer 103, and a conductive film 104 are sequentially deposited on 1, and then the conductive film 104 and the insulating layer 103 are etched away using lithography technology, and the opening of the cavity 105 is filled with a suitable material. A cathode emitter protrusion 108 is formed on the conductive film 102 in the cavity 105 by gradually thinning the cathode material 107 from directly above the opening while gradually spacing it by rotating oblique evaporation 106. . Finally, by removing the substance 106, an electron-emitting device can be manufactured as shown in FIG. 6(b).

Then, a power source 109 is connected so that the conductive film 104 is positive and the conductive film 102 is negative, and the cathode emitter protrusion 108
By applying a voltage higher than a predetermined voltage determined by the cathode material 107 of the cathode emitter protrusion 10, the electric field is concentrated.
Electrons can be emitted from B.

There are also attempts to make the above electron-emitting devices into arrays and apply them to flat displays (Japan Display'
86, P512).

As another example of the conventional electron-emitting device, the structure described in Japanese Patent Application No. 1-330740 previously filed by the present inventors is known. FIG. 7 is a perspective view showing the conventional electron-emitting device.

As shown in FIG. 7, a cathode material layer 112 and an insulator layer 113 sandwiching the cathode material layer 112 are formed on an electrically insulating substrate 111, and a control electrode 1 is formed on the insulator layer 113.
14 is formed.

Then, by connecting a power source (not shown) so that the control electrode 114 is positive and the cathode material layer 112 is negative, and applying a voltage higher than a predetermined voltage between the two, the control electrode 11
By concentrating an electric field on the edge portion 115 of the cathode material layer 112 facing 3, electrons can be emitted from this edge portion 115.

Problems to be Solved by the Invention However, in the former of the above conventional examples, when producing the cathode emitter protrusion 108 in the cavity 105, rotary oblique evaporation and forward evaporation performed from directly above are performed at the same time.
It is very difficult to accurately control this simultaneous vapor deposition.

In addition, the latter has the advantage that it is easier to manufacture and can be manufactured at a higher yield than the former, but the control electrode 114 that provides a positive potential of a predetermined magnitude with respect to the cathode 112 K is placed on the amphoteric side of the cathode 112. Moreover, the cathode 112
Since the cathode 112 is disposed at a higher position, the electron beam extracted from the cathode 112 tends to spread outward, resulting in a problem that the quality of the electron beam deteriorates.

The present invention solves the problems of the prior art as described above, and makes it possible to obtain a high-quality and high-definition electron beam, as well as to manufacture with a high yield and improve reliability. It is an object of the present invention to provide an electron-emitting device that can easily and stably extract an electron beam.

Means for solving the problem The technical solution of the present invention for achieving the above object is as follows:
First, an insulating substrate, a cathode material layer having an edge portion formed on the insulating substrate, an insulator layer formed on the cathode material layer, and an insulator layer formed on the insulator layer. a first control electrode formed, an insulator layer formed on the insulating substrate outside the cathode material layer, the insulator layer and the first control electrode, and an insulator layer formed on the insulator layer; The device includes a second control electrode electrically connected to the first control electrode.

Second, the electrical connection between the first control electrode and the second control electrode is via an electrical connection on an insulator layer formed on the cathode material layer and a predetermined portion of the insulating substrate. It is something that can be done.

Third, the electrical connection between the first control electrode and the second control electrode is made through a cathode material layer, an insulator layer formed on this cathode material layer, and an insulator formed on an insulating substrate. This is done through an insulated electrical connection through an insulator layer formed at a predetermined distance on the outside of the cathode material layer and the cathode material layer.

Fourthly, in the first technical solution, the second
An insulator layer is formed on the control electrode, and an extraction electrode is formed on the insulator layer.

Therefore, according to the present invention, the cathode material layer and the first and second
When a voltage is applied between the control electrode and the cathode material layer, an electric field is concentrated on the edge of the cathode material layer and electrons are emitted. At this time, the first control electrode directs the electron beam toward the second control electrode. The centripetal force of the electron beam can be generated by suppressing the electron beam so that it is not directed, and the spread of the electron beam can be suppressed. Moreover, since the structure is simple, it can be easily manufactured.

Further, by providing an extraction electrode, acceleration can be applied to the emitted electron beam.

EXAMPLES Hereinafter, examples of the present invention will be described with reference to the drawings.

First, a first embodiment of the present invention will be described.

FIG. 1 is a sectional view of an electron-emitting device according to a first embodiment of the present invention.

As shown in FIG. 1, its structure is such that Mo is placed in the center of an insulating substrate 1 made of glass, ceramics, etc.

A cathode material layer 2 made of Ta, W, ZrC, LaB@, etc. is formed, and on this cathode material layer 2 Stow, A
Itos.

An insulator layer 3 made of 5LNa or the like is formed. This insulator layer 3 is set to a size such that the edge portion 4 of the cathode material layer 2 is exposed. Mo, Ta are on the insulator layer 3.
, Cr, AI, Au, etc., the first control electrode 5
is formed. On the outer periphery of the insulating substrate 1, Sio! , Altos,
An insulator layer 6 made of 5isNa or the like is formed, and on this insulator layer 6 are made of Mo, Ta, Cr, AI.

A second control electrode 7 made of Au or the like is formed.

The first control electrode 5 and the second control electrode 7 are electrically connected.

The electrical connection between the first and second control electrodes 5 and 7 can be seen, for example, in the plan view of the electron-emitting device in one embodiment of the present invention shown in FIG. 1′
As shown in the cross-sectional view (FIG. 2(b)) (the same parts are indicated by the same numbers), a part of the exposed part of the cathode material layer 2 and the connection between the cathode material layer 2 and the surrounding insulator layer 6 are shown. A part of the exposed part of the insulating substrate 1 between 5iOs, Altos, 5i
An insulator layer 8 made of sNa or the like is formed, and on this insulator layer 8 are made of Mo, Ta, Cr.

An electrical connection portion 9 made of AI, Au, etc. is formed, and the first control electrode 5 and the second control electrode 7 are electrically connected.

The operation of the above configuration will be described below.

Connect to a power source (not shown) so that the cathode material layer 2 is negative and the first and second control electrodes 5 and 7 are positive, and a voltage higher than a predetermined voltage determined by the cathode material layer 2 is applied between them. By applying the electric field, the electric field is concentrated on the edge portion 4 of the cathode material layer 2, and electrons are emitted from the edge portion 4 into an external vacuum. The trajectory of the electrons emitted into the vacuum is determined along the lines of electric force of the voltage determined by the first control electrode 5, the second control electrode 7, and the cathode material layer 2. therefore,
Without the first control electrode 5, the lines of electric force would follow the direction of the second control electrode 7, that is, along the lines of electric force pointing outward from the center of the electron-emitting element, and the emitted electron beam would spread. However, by providing the first control electrode 5, it is possible to generate a centripetal force toward the center of the electron-emitting device, suppress the spread of the electron beam, and improve the quality of the electron beam.

Although the insulator layer 6 and the second control electrode 7 were formed to surround the periphery in the above embodiment, they were formed to sandwich the cathode material layer 2, the insulator layer 3, and the first control electrode 5 on both sides. You can.

Next, a third embodiment of the present invention will be described.

3(a) and 3(b) show an electron-emitting device according to a third embodiment of the present invention, FIG. 3 (al is a plan view, FIG. It is a sectional view along a line.

As shown in FIGS. 3(al) and (b), the insulating substrate 1 has an insulating layer 10 thereon, and a ring-shaped cathode material layer 2 is formed on the center of the insulating layer 10. An insulator layer 3 is formed on the cathode material layer 2 and on the exposed portion of the insulator layer 10 inside the cathode material layer 2. This insulator layer 3 has an exposed edge portion 4 of the cathode material layer 2. A first control electrode 5 is formed on the insulator layer 3. A cathode material layer 2 and an insulator layer 3 are formed on the outer periphery of the insulator layer 10. and the outer periphery of the first control electrode 5,
An insulator layer 6 is formed at predetermined intervals, and a second control electrode 7 is formed on this insulator layer 6.

Then, an insulated electrical connection part 11 is formed through the insulator layer 3, cathode material layer 2, insulator layer 10, and insulator layer 6, and this electrical connection part 11 connects the first control electrode 5.
and the second control electrode 7 are electrically connected.

The materials used for each part of this embodiment and the operation of this embodiment are the same as those of the first embodiment, so the explanation thereof will be omitted.

Next, a fourth embodiment of the present invention will be described.

FIG. 4 is a sectional view showing an electron-emitting device according to a fourth embodiment of the present invention.

In this embodiment, the same parts as in the first embodiment are given the same reference numerals, and the explanation thereof will be omitted, and the different configurations will be explained. As shown in FIG. 4, there are Sin, AI! on the second control electrode 7. An insulator layer 12 made of 01°5iaNa or the like is formed, and an extraction electrode 13 made of Mo, Ta, W, Cr, AI, Au or the like is formed on this insulator layer 12.

The operation of the above configuration will be described below.

Connect to a power source (not shown) so that the cathode material layer 2 is negative and the first and second control electrodes 5 and 7 are positive, and a voltage higher than a predetermined voltage determined by the cathode material layer 2 is applied between them. By doing so, an electric field is concentrated on the edge portion 4 of the cathode material layer 2, and electrons are emitted from the edge portion 4 into an external vacuum. As explained in the first embodiment, the electrons emitted into the vacuum generate a centripetal force toward the center of the electron-emitting element due to the action of the first control electrode 5, resulting in an electron beam whose spread is suppressed. becomes. Here, if a voltage lower than a predetermined voltage is applied between the cathode material layer 2 and the first and second control electrodes 5 and 7, electrons will not be emitted from the cathode material layer 2 into the vacuum. By controlling the voltage, the amount of electrons emitted can be controlled. Furthermore, by setting the extraction electrode 13 at a higher potential than the first and second control electrodes 5 and 7, it is possible to give upward acceleration to the electron emitting device to the electrons emitted into the vacuum. The spread of the electron beam to the outside can be suppressed and the electron beam can be easily extracted.

Next, a specific example of the electron-emitting device of the present invention is shown in FIG.
The manufacturing process will be explained with reference to the cross-sectional views shown in al to (g) for explaining the manufacturing process.

As shown in FIG. 5(a), a glass plate with a thickness of 1 mm is used as the insulating substrate 1, and a cathode material layer 2 made of Mo, W, etc. is placed on the center of the insulating substrate 1. The thickness is 200 to -400 nm, the width is 10 to 50 μm, and the length is 2 by electron beam evaporation or sputter evaporation.
00 μm. Next, as shown in FIG.
It was formed to a thickness of ~48 μm. Next, as shown in FIG. 5 (cl), from above the resist 14 and the cathode material layer 2, an insulator layer 3 of 5ins or the like is formed to a thickness of 800 nm to 1 μm, and a first control electrode 5 is made of a conductive material such as Mo. , or Cr
etc. were continuously formed to a thickness of 200 to 400 nm by K electron beam evaporation or sputter evaporation. Next, by lifting off the resist 14, an insulator layer 3 and a first control electrode 5 were formed on the cathode material layer 2, as shown in FIG. As shown in the figure (el), the first control electrode 5 is
A pattern of a mask 15 was formed to have a width of 12 to 55 μm and a thickness of 2.5 μm so as to partially cover the exposed portions of the cathode material layer 2 and the insulating substrate 1. Next, as shown in FIG. 5, the insulating layer 6 is
5ins to 800nm to 1μm 1 The second control electrode 7 is made of conductor MOI or Cr with a thickness of 200 nm.
~400 nm, 5ins etc. as insulator layer 12 for 80
0 nm to 1 μm 1 M as a conductor as the extraction electrode 13
Ol or Cr was continuously formed to a thickness of 200 to 400 nm by electron beam evaporation or sputter evaporation. Thereafter, by lifting off the mask 15, an electron-emitting device having a second control electrode 7 and an extraction electrode 13 was produced as shown in FIG. 5(g). When an electron beam was imaged on a fluorescent surface using the electron-emitting device produced as described above, a good electron beam image with a width of 10 to 55 μm and a length of 2004 m was obtained.

Effects of the Invention As described above, according to the present invention, the cathode material layer and the first,
When a voltage is applied between the second control electrode and the cathode material layer, the electric field is concentrated on the edge of the cathode material layer and electrons are emitted. At this time, the first control electrode directs the electron beam to the second control electrode. The centripetal force of the electron beam can be generated by suppressing the electron beam so that it is not directed in the same direction, and the spread of the electron beam can be suppressed. Therefore, a high-quality, high-definition electron beam can be obtained. Moreover, since the structure is simple, it can be manufactured easily, and therefore, the yield can be improved and reliability can be improved.

Further, by providing an extraction electrode, acceleration can be applied to the emitted electron beam.

Therefore, the electron beam can be easily and stably extracted.

[Brief explanation of drawings]

FIG. 1 shows a cross-sectional view of an electron-emitting device according to a first embodiment of the present invention, and FIG. (■-1' of al
3(a) is a plan view of the third embodiment of the present invention, and FIG. 3(b) is a sectional view taken along the line of FIG.
4 is a cross-sectional view showing an electron-emitting device according to a fourth embodiment of the present invention, and FIG. FIG. 6(ta) is a sectional view showing a conventional electron-emitting device in a state in the middle of manufacturing, FIG. 6(bl) is a sectional view showing a completed manufacturing state, and FIG. It is a perspective view showing an electron-emitting device. 1... Insulating substrate, 2... Cathode material layer, 3... Insulator layer, 4... Edge part, 5... First control electrode ,
6... Insulator layer, 7... Second control electrode, 8...
Insulator layer, 9... Electrical connection part, 10... Insulator layer, 11... Electrical connection part, 12... Insulator layer, 13
...Extraction electrode. Name of agent: Patent attorney Akira Okaji and two others Figure 2 Figure 7 Second control electrode Figure (b) Insulator layer Figure 6 Insulator layer Figure (b) Figure Figure 7

Claims (4)

[Claims] (1) An insulating substrate, a cathode material layer having an edge portion formed on the insulating substrate, an insulator layer formed on the cathode material layer, and a cathode material layer formed on the insulator layer. an insulator layer formed on the insulating substrate at a predetermined interval outside the cathode material layer, the insulator layer and the first control electrode; An electron-emitting device comprising a second control electrode formed thereon and electrically connected to the first control electrode. (2) The electrical connection between the first control electrode and the second control electrode is via an electrical connection on an insulator layer formed on the cathode material layer and a predetermined portion of the insulating substrate. The electron-emitting device according to claim 1, characterized in that: (3) The electrical connection between the first control electrode and the second control electrode is made through a cathode material layer, an insulator layer formed on the cathode material layer, and an insulator formed on an insulating substrate. The electron-emitting device according to claim 1, wherein the electron-emitting device is made through an insulated electrical connection portion through an insulating layer formed at a predetermined interval on the outside of the cathode material layer. . (4) The method according to any one of claims 1 to 3, further comprising an insulating layer formed on the second control electrode and an extraction electrode formed on the insulating layer. Electron-emitting device.