JPH02121227A - Electron emission element and manufacture thereof - Google Patents

Abstract

PURPOSE:To make it possible to obtain a uniform electron emission distribution by providing an insulation layer on a conductive material, then providing a metal layer on the insulation layer, and providing the electron emission part of this metal layer with thick layer parts and thin layer parts. CONSTITUTION:A conductive material 1 is formed on a substrate 5 by vacuum deposition, sputtering, etc. An insulation layer 2 is then formed on the conductive material 1 at a part corresponding to an electron emission surface 4. A metal layer 3 is then formed by vacuum deposition, sputtering, etc., consisting of thin parts 3a and thick parts 3b. By applying a voltage between the conductive material 1 and the metal layer 3 of such an electron emission element to make the metal layer 3 positive, the voltage is supplied to the thin parts 3a through the thick parts 3b of the metal layer 3. In this case, a voltage drop is small at the thick parts 3b of the metal layer 3, while the voltage is supplied to each thin part 3a uniformly. Emission electrons 6 are thus emitted uniformly from the thin parts 3a for the electron emission surfaces.

Description

[Detailed Description of the Invention] Industrial Fields of Application The present invention is applicable to electron microscopes, electron beam exposure devices, CRTs, etc.
The present invention relates to an electron-emitting device that can be used as an electron source for various electron beam application devices, and a method for manufacturing the same.

BACKGROUND OF THE INVENTION Conventionally, hot cathodes have been used as electron generators in electron beam devices such as electron microscopes and CRTs. but,
Electron emission using a hot cathode requires heating means, which poses problems such as energy loss due to heating. Therefore, research has been conducted on electron emission without heating, so-called cold cathodes, and several types of electron-emitting devices have been proposed.

For example, there is the PN junction type, in which a reverse bias voltage is applied to the PN junction to cause an electron avalanche breakdown phenomenon that causes electrons to be emitted, and the field effect type, in which a locally high-density electric field is applied to the metal to emit electrons. , an MIM type with a metal layer-insulator layer-metal layer configuration, in which electrons that have passed through the insulator layer are emitted from the metal layer to the outside of the element by applying a voltage between the two metals due to the tunnel effect. Electron-emitting devices have been proposed.

Among the cold cathodes, the MIM type electron-emitting device will be described in detail with reference to FIG.

The MIM type electron-emitting device is made of metal 2 as shown in Fig. 3.
It has a structure in which a thin metal layer 23 is laminated on top of the metal layer 23 with a thin insulator layer 22 interposed therebetween. By applying a voltage greater than the work function of the metal 23 between the metals 21 and 23 by the power supply 24, electrons having energy greater than the vacuum level among the electrons tunneled through the insulating layer 22 are transferred to the surface of the metal 23. The electrons are emitted as emitted electrons 25. In order to obtain high electron emission efficiency, the insulator layer 22
It is desirable to form each metal 23 as thinly as possible within a range that does not cause dielectric breakdown, and within a range that allows sufficient current to flow through the metal 23.

As such, for example, Japanese Patent Application Laid-Open No. 634532
The configuration described in the publication is known. The configuration will be briefly explained below using FIG. 4.

FIG. 4 shows that a first metal layer 32 is formed on an insulating substrate 31,
An insulator layer 33 is formed thereon, and a second
In the structure in which a metal layer 34 is formed, the metal layers 32 and 3
By applying a voltage between 40 and 40 from a power source 36, electrons 37 are emitted from a portion of the surface of the metal layer 34 that corresponds to the ridge line 35 of the metal layer 32.

Problems to be Solved by the Invention However, in conventional MIM type electron-emitting devices, the electron emission distribution becomes uneven or fluctuates due to partial non-uniformity in the thickness of the metal layer corresponding to the electron-emitting surface. There was an issue of how to do this. In addition, when the metal layer is made thinner, the potential drop across the metal layer becomes larger and a difference occurs in the potential applied between the center and the periphery of the metal layer, which may cause the electron emission distribution to vary depending on the location. In some cases, no release was obtained.

In view of the non-uniformity of the electron emission distribution of conventional MIM type electron emitting devices as described above, the present invention aims to provide a MIM type electron emitting device with a uniform electron emission distribution and a method for easily manufacturing the same. This is the purpose.

Means for Solving the Problems The first aspect of the present invention is to provide an insulating layer on a conductive material, further provide a metal layer on the insulating layer, and make the electron emitting part of the metal layer a thick part. A thin portion is provided.

A second aspect of the present invention is a method for manufacturing the electron-emitting portion of the metal layer, in which the metal layer is first applied to a uniform thickness, and then,
The parts that need to be thinned are made thinner using methods such as etching.

According to the first aspect of the present invention, with the above structure, a potential is supplied from the thick part of the layer of the electron-emitting portion, and electrons are emitted from the thin part, so that a uniform electron emission distribution can be obtained in the electron-emitting efficient body.

Further, in the second aspect of the present invention, an electron-emitting device having the above-mentioned function can be easily manufactured by the above-described manufacturing method.

Embodiments Hereinafter, embodiments of the present invention will be described with reference to FIG.

FIG. 1(a) is a schematic cross-sectional view of an electron-emitting device according to a first embodiment of the present invention, and FIG. It is a diagram.

In the figure, l is a conductive material, 2 is the conductive material 1
3 is the metal layer on the insulator layer 2, 4 is the electron emitting surface of the metal layer 3, 5 is the bottom substrate, and 6 is the emitted electron emitted from the electron emitting surface 4. It is.

The electron-emitting device of the present invention is manufactured as follows.

That is, A as a conductive material 1 is placed on a substrate 5 made of glass.
I thin film is deposited for 30 minutes by vacuum evaporation or sputtering.
00 A to 5000 A is formed, then 12110
On the conductive material 1 in a portion corresponding to the electron emitting surface 4 of approximately 0 μm, an insulator layer 2 of 50 to 200 A is formed using a method such as vacuum evaporation, sputtering, or anodic oxidation as an insulator layer 2, such as AIto or SIO. Furthermore, as a metal layer 3, for example, Au or M is formed on the thin part 3a with a film thickness of about 50A to 2OOA, as shown in FIG. 1(b).
It is formed by a method such as vacuum evaporation or sputtering so as to have a thick portion 3b of about 000 Å.

The method for forming the thin and thick parts of the metal layer 3 is to form Au or M on the insulator 2 by vacuum evaporation or sputtering to a thickness of about 100 OA, and then apply a 7-inch photoresist thereon. , by pattern exposure and development with a pitch of about 10 μm, the photoresist in the portion corresponding to the electron emission surface 4 that should be thinned is removed, the metal layer 3 is etched to near the surface of the insulator layer 2, and the remaining portion is etched. is formed by removing the photoresist.

When a voltage is applied between the conductive material 1 and the metal layer 3 of the electron-emitting device as described above so that the metal layer 3 becomes positive, the voltage is applied to the thin part 3a of the metal layer 3 through the thick part 3b. Supplied. In this case, the voltage drop at the thick portion 3b of the metal layer 3 is small and the voltage is uniformly supplied to each of the thin portions 3a, so that the emitted electrons 6 are uniformly emitted using the thin portion 3a as an electron emitting surface.

Next, a second embodiment of the present invention will be described with reference to FIG.

FIG. 2(a) is a schematic cross-sectional view of an electron-emitting device according to a second embodiment of the present invention, and FIG. 2(b) is an enlarged view of its electron-emitting surface. As in the first embodiment, 11 is a conductive material, 12 is an insulating layer, 13 is a metal layer, 14 is an electron emitting surface,
15 is a substrate, and 16 is an emitted electron. This embodiment is similar to that shown in FIG. 1 except that the etched shape of the metal layer 13 is different.
This is the same as the embodiment (b), and the explanation will be omitted.

Effects of the Invention As described above, the first invention can obtain a uniform electron emission distribution. Further, according to the second aspect of the present invention, an electron-emitting device that can obtain a uniform electron emission distribution can be easily manufactured.

[Brief explanation of the drawing]

FIG. 1 (al is a schematic sectional view of an electron-emitting device in the first embodiment of the present invention, FIG. 1(b) is an enlarged sectional view of the electron-emitting part of the same embodiment, and FIG. 2(a) is a schematic sectional view of the electron-emitting device in the first embodiment of the present invention. A schematic cross-sectional view of an electron-emitting device according to a second embodiment of the invention, FIG. 2(b) is an enlarged cross-sectional view of an electron-emitting portion of the same embodiment, and FIG. 3 is a general configuration of a conventional MIM type electron-emitting device. A schematic cross-sectional view showing
FIG. 4 is a schematic cross-sectional view of a conventional electron-emitting device. 1.11... Conductive material, 2,12... Insulator layer,
3゜13...metal layer, 4,14...electron emission surface, 5
, 15... Substrate, 6.16... Emitted electron. Figure 1 (0”) Name of agent Patent attorney Shigetaka Awano and one other person (b) Figure Figure Figure

Claims (2)

[Claims] (1) It has a conductive material, an insulator layer formed on the conductive material, and a metal layer further formed on the insulator layer, and the electron emitting portion of the metal layer is thin. An electron-emitting device characterized by having a thick portion and a thick portion. (2) A step of forming a conductive material on a glass substrate by vacuum evaporation or sputtering, a step of forming an insulating layer on this conductive material by sputtering or anodic oxidation, and a step of forming a metal layer on this insulating layer. A method for manufacturing an electron-emitting device, comprising a step of forming it by vacuum evaporation or sputtering, and a step of forming a photoresist in a predetermined pattern on the metal layer and then etching it.