JP2654012B2 - Electron emitting device and method of manufacturing the same - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electron-emitting device and a method for manufacturing the same, and more particularly, to an electron-emitting electrode having a tip and a counter electrode provided to face the tip. And a method of manufacturing the same.

(Prior art)

Conventionally, thermionic emission from a hot cathode has been used as an electron source. Electron emission using such a hot cathode is
There are problems in that energy loss due to heating is large, that a heating means needs to be formed, that preheating takes a considerable amount of time, and that the system tends to be unstable due to heat.

Therefore, research on electron-emitting devices that do not rely on heating has been advanced, and one of them is a field-effect (FE) electron-emitting device.

FIG. 7 is a schematic configuration diagram of a conventional field-effect type electron-emitting device.

As shown in the figure, the conventional field-effect type electron-emitting device has a cathode chip 20 provided on a base 23 and having a sharply sharpened tip for obtaining a strong electric field, and an insulating layer 21 on the base 23. And a lead electrode 22 having a substantially circular opening centered on the tip of the cathode chip 20. The lead electrode 22 is positioned between the cathode chip 20 and the lead electrode 22. A voltage as a potential is applied, and electrons are emitted from the pointed tip of the cathode chip 20 where the electric field intensity increases.

[Problems to be solved by the invention]

However, it is difficult for the above-mentioned conventional field-effect type electron-emitting device to sharply sharpen the tip of the cathode chip 20, and in general, when manufacturing the cathode chip 20, remolding is performed after electrolytic polishing. Was. This process requires a lot of trouble and is complicated, and also has problems such as difficulty in mechanization, liability to be generated in manufacturing conditions, and unstable quality due to strong empirical factors.

SUMMARY OF THE INVENTION An object of the present invention is to provide a field-effect type electron-emitting device and a method for manufacturing the same, in which the manufacturing process of the pointed tip of the electron-emitting cathode is simplified and the thickness is reduced. Is to do.

[Means for solving the problem]

In the electron-emitting device according to the present invention, an electron-emitting electrode having a protruding end and a counter electrode facing the protruding end are arranged at intervals in the same plane of the insulating base. The insulating base has a concave portion below the protruding end of the electrode for use, below the end of the counter electrode facing the protruding end, and between the protruding end and the counter electrode.

Further, the method for manufacturing an electron-emitting device according to the present invention is characterized in that the conductive layer laminated on the same surface of the insulating substrate has an interval between the electron-emitting electrode having the tip and the counter electrode facing the tip. And etching the insulating substrate at least below the projecting end of the electron-emitting electrode, below the end of the counter electrode facing the projecting end, and between the projecting end and the counter electrode. And forming a concave portion with the method.

(Operation)

In general, the electric field intensity required for field emission is 10 ⁶ V / cm or more. When this electric field is applied, electrons in the solid pass through a potential barrier on the surface due to a tunnel effect and are emitted.

Now, assuming that the voltage applied between the opposing electrode for electron emission and the counter electrode is V, and the radius of curvature of the electron emission portion of the electron emission electrode is r, if the radius of curvature r is small, The electric field strength E is There is a relationship.

When performing electron emission, in order to improve the convergence of electrons, it is desirable to reduce the energy width of the emitted electrons, and it is desirable to be able to drive at a low voltage. Therefore, it is desirable that the radius of curvature r be as small as possible.

Further, in order to suppress variations in the electron emission voltage, it is desired that the distance between the electron emission electrode and the counter electrode be formed with high accuracy.

By forming the electron emission electrode and the counter electrode on the same surface, the present invention makes it possible to use a microfabrication technique such as FIB for the production of both electrodes, and to minimize the radius of curvature of the electron emission electrode. The distance between the electron emission electrode and the counter electrode is precisely formed.

〔Example〕

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

FIG. 1 is a schematic structural view showing a first embodiment of the electron-emitting device of the present invention.

As shown in the figure, a conductive layer is laminated on an insulating substrate 1 such as glass by about 500 ° by evaporation or the like.
The electron emission electrode 2 and the counter electrode 3 are formed by using a maskless etching technique such as IB.

The protruding end of the electron-emitting electrode 2 is processed into a triangular shape, a parabolic shape, or the like using the FIB or the like so as to minimize the radius of curvature, and has a wedge-shaped columnar body and a parabolic side surface. It is formed in a columnar body or the like.

The material of the electron emission electrode 2 is formed so that the radius of curvature of the electron emission electrode 2 is reduced as described above, and the current density is increased and the calorific value is increased. Preferably, it is made of a low work function material in order to reduce the applied voltage. For example, W, Zr, metal such as Ti, TiC, ZrC, metal carbide such as HfC,
Metal borides such as LaB ₆ , SmB ₆ , GdB ₆ , WSi ₂ , TiSi ₂ , ZrSi ₂ , G
Metal silicide such as dSi ₂ can be used.

Although the shape of the counter electrode 3 is not particularly limited,
As shown in this embodiment, if the electrode is formed linearly so as to face the protruding end of the electron-emitting electrode 2, the fabrication is easy and electrons can be efficiently emitted from the electron-emitting electrode 2.

In the electron-emitting device having such a configuration, the power supply 4 supplies the counter electrode 3 between the electron-emitting electrode 2 and the counter electrode 3.
Is applied, a strong electric field is applied to the tip of the electron-emitting electrode 2, and electrons are emitted.
The emission current density J at this time is calculated using Fowler-Nordheim equation, Given by

For example, the tip of the electron emission electrode 2 has a hyperbolic blade opening angle of 30 °, a distance of 0.1 μm from the counter electrode, and a voltage of 80 V.
Then, the obtained electric field is 2.0 × 10 ⁷ V / cm, and the obtained emission current density J is J = 3.7 × 10 ⁻² A / cm ² when the work function of the metal is φ = 3.5.

Some of the electrons emitted from the protruding end of the electron emission electrode 2 are absorbed by the counter electrode 3, and the electrons emitted by the electron beam diffraction phenomenon have low energy due to the low energy of the electrons. There are electrons that are scattered by the crystal lattice and are emitted in a direction perpendicular to the insulating substrate 1, and electrons having a motion component in a direction perpendicular to the insulating substrate 1 can be used as an electron source.

In order to improve the electric field strength between the electron emission electrode 2 and the counter electrode 3 and to efficiently extract electrons without charging the emitted electrons onto the insulating substrate, it is necessary to use a technique such as dry etching. It is desirable to dig deep into the insulating substrate surface at the portion where the electric field is concentrated using the method. Hereinafter, the manufacturing process will be described.

2 (A) to 2 (D) are schematic explanatory views for explaining a manufacturing process for forming a concave portion on a substrate.

First, as shown in FIG. 2A, an SiO ₂ layer 6 is formed on a Si substrate 5 by thermal oxidation or the like.

Next, as shown in FIG. 2B, a conductive layer 7 of tungsten (W) or the like is formed.

Next, as shown in FIG. 2 (C), an electron emission electrode 2 having a protruding end portion shape and a linear counter electrode 3 are formed by using a fine processing technique such as FIB.

Next, as shown in FIG. 2 (D), the SiO ₂ layer 6 is etched by selective etching such as wet etching using a hydrofluoric-nitric acid-based etchant and plasma etching using a reactive gas such as CF ₄ . At this time, the etching is performed through the opening between the electron emission electrode 2 and the counter electrode 3, and the etching is performed isotropically to form a concave portion. The portion 6 of the SiO ₂ layer that will become part is completely removed.

 Next, the fine processing technology used in the present invention will be described.

Usually, a lithography technique including a resist process and an etching process is used as the fine processing technique. However, fine processing of 0.7 μm or less is difficult because a mask shift occurs.

The microfabrication technology used in the present invention refers to a technology capable of performing microfabrication of 0.7 μm or less. For example, the above-described FIB is used.

FIG. 3 is a configuration diagram of an example of the FIB device. FIB technology
Sub-micron focused metal ions are scanned, and fine processing on the order of sub-microns is performed by utilizing the sputtering phenomenon on the solid surface.

In the figure, an ion source 9 emits liquid metal atoms by an extraction electrode, selects a desired ion beam by an EXB mass separator 11 (when using an alloy-based liquid metal), and accelerates it to about 80 KeV by an objective lens 12. The focused ion beam is focused to about 0.1 μm, and the deflection electrode 13 scans the base 14. The alignment of the ion beam is performed by the sample stage 15.

FIG. 4 is a schematic sectional view showing a second embodiment of the electron-emitting device of the present invention.

As shown in the figure, the electron-emitting device of the present embodiment has a draw-out electrode 16 for effectively drawing out electrons having each motion vector from an electron source having the same structure as that of the above-described embodiment.
Is provided above the electron source. When a voltage for raising the potential of the extraction electrode 16 is applied between the electron emission electrode 2 and the extraction electrode 16 by the power supply 17, the electrons emitted from the electron emission electrode 2 are efficiently transferred to the insulating substrate 1. In contrast, it can be taken out vertically.

FIG. 5 is a schematic configuration diagram showing a third embodiment of the electron-emitting device of the present invention.

As shown in the figure, the electrode 2 for electron emission has a plurality of protruding portions formed by using a fine processing technique such as FIB, and the distance between each protruding portion and the opposing electrode 3 is formed with high precision. Therefore, there is little variation in the applied voltage for electron emission, and the amount of electrons emitted from each tip is substantially the same.

FIG. 6 is a schematic explanatory view showing a fourth embodiment of the electron-emitting device of the present invention.

As shown in the figure, the electron-emitting device of the present embodiment faces the wiring 18 _{1-18 5} having a plurality of projecting portions, the projecting end of each wiring 18 _{1-18 5} and are arranged in a matrix and the a plurality of electron emission regions a by the wiring 19 _{1-19 5} having a counter electrode formed in a configuration, sequentially wiring 18 _{1-18 5}
And OV, in accordance with the scanning, when applied to the transistor Tr ₁ to Tr ₅ are respectively connected to predetermined voltage V to the wiring 19 _{1-19 5,} it is possible to emit electrons from a desired electron emitting portion .

〔The invention's effect〕

As described above in detail, according to the present invention, the radius of curvature of the cathode can be formed as small as possible, and the distance between the electron emission electrode and the counter electrode can be formed with high accuracy. effective.

(1) Low-voltage driving is possible, and variations in the energy of emitted electrons can be reduced.

(2) Since the electron emission electrode and the counter electrode are formed with high precision by the fine processing technology such as FIB, a manufacturing process such as remolding is unnecessary, and the manufacturing process can be simplified.

(3) Since the electron emission electrode and the counter electrode are finely processed in a planar manner, it is easy to reduce the thickness, size, and weight.

Further, according to the present invention, at least a recess is formed in the insulating base between the protruding portion and the counter electrode, below the protruding portion of the electron emission electrode, below the protruding portion of the opposing electrode, and between the protruding portion and the opposing electrode. By doing so, electrons can be efficiently extracted without charging up the electrons emitted from the protruding end portion to the insulating base surface.

[Brief description of the drawings]

FIG. 1 is a schematic structural view showing a first embodiment of the electron-emitting device of the present invention. 2 (A) to 2 (D) are schematic explanatory views for explaining a manufacturing process for forming a concave portion on a substrate. FIG. 3 is a configuration diagram of an example of the FIB device. FIG. 4 is a schematic sectional view showing a second embodiment of the electron-emitting device of the present invention. FIG. 5 is a schematic configuration diagram showing a third embodiment of the electron-emitting device of the present invention. FIG. 6 is a schematic explanatory view showing a fourth embodiment of the electron-emitting device of the present invention. FIG. 7 is a schematic configuration diagram of a conventional field-effect type electron-emitting device. DESCRIPTION OF SYMBOLS 1 ... Insulating substrate, 2 ... Electron emission electrode, 3 ... Counter electrode, 4, 17 ... Power supply, 8 ... Depression, 16 ... Extraction electrode.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Akira Suzuki 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Isamu 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon (72) Inventor Toshihiko Takeda 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Masahiko Okunuki 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. ( 56) References JP-A-59-105252 (JP, A) JP-A-63-274048 (JP, A) JP-A-56-167456 (JP, U) JP-B-46-20944 (JP, B1) JP-B 54-17551 (JP, B2)

Claims (7)

(57) [Claims] An electron emitting electrode having a protruding end portion and a counter electrode facing the protruding end portion are arranged on the same surface of the insulating substrate with a space therebetween. An electron-emitting device having a concave portion in the insulating base below the protruding end, below the end of the counter electrode facing the protruding end, and between the protruding end and the counter electrode. 2. The electron-emitting device according to claim 1, wherein at least a constituent material of said protruding portion is made of a material having a high melting point and a low work function. 3. An electron-emitting device according to claim 1, wherein said electron-emitting electrode has a plurality of protruding ends. 4. The electron-emitting device according to claim 1, wherein an extraction electrode is provided on the protruding end. 5. The electron-emitting device according to claim 3, wherein the wiring having the plurality of protruding portions and the wiring having opposing electrodes formed to face the respective protruding portions are arranged in a matrix. . 6. A step of forming an electron emitting electrode having a protruding end and a counter electrode facing the protruding end with an interval from a conductive layer laminated on the same surface of the insulating base; Forming a concave portion by etching in the insulating substrate between the protruding end of the electron-emitting electrode, the lower end of the counter electrode facing the protruding end, and the space between the protruding end and the counter electrode; A method for manufacturing an electron-emitting device, comprising: 7. The electron-emitting device according to claim 6, wherein the electron-emitting electrode having the protruding end and the counter electrode facing the protruding end are formed by finely processing the conductive layer. Production method.