JPS6310448A - electron emitter - Google Patents

Abstract

PURPOSE:To enable a sufficiently fine electron beam to strike a target surface by satisfying a specific ratio relationship between thickness of an insulator and diameter of an electron emission outlet. CONSTITUTION:An electron emission outlet 2 of diameter L is formed in an insulator 1 of thickness T, and the electron emission outlet has such a long and narrow shape that saticfies the relationship T>= 5L. Since the length of the outlet near opening where the electric field distribution makes the electron beam divergent is usually the same order as the diameter L of the electron emitting aperture 2, electron can be adequately accelerated and the influence on the electron beam due to the electric field distribution near the opening can be decreased provided that the length T of the electron emission outlet 2 keeps as five times as the diameter L. Further, its is desirable that the thick ness T of the insulation layer would satisfy the same condition from the view point that a high acceleration voltage is applied between an acceleration elec trode 3 and a metal layer 4.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an electron emitting device, and more particularly to an electron emitting device having an electron emitting source and an accelerating electrode provided at an electron emitting port of the electron emitting device.

[Prior art] ``Electron emission sources conventionally include those that use avalanche breakdown of a PN junction, those that apply a forward bias to a PM junction and inject electrons into two layers, and those that use a thin insulating layer made of metal. A variety of electron-emitting devices have been proposed, including those having a sandwiched structure (H2N type), surface conduction type devices in which electrons are emitted by passing a current through a rough high-resistance thin film, and field emission type devices.

In such electron-emitting devices, an accelerating electrode is generally provided at the electron-emitting port to accelerate electrons emitted from the surface of the device and to reduce the JG function by the Schottky effect, thereby improving electron-emitting efficiency. . Further, an electrostatic lens such as an Einzel lens or a pi-potential lens is provided to focus the emitted 1[son beam on a target surface such as a wafer.

[Problems to be Solved by the Invention] However, in the conventional electron emitting device, in order to prevent the electron beam from spreading, it is necessary to provide a focusing electrode, a lens electrode, etc. in addition to the accelerating electrode, which complicates the structure. There was a problem.

Furthermore, since the accelerating electrodes and lens electrodes of the electron emitting aperture were installed separately on the electron emitting surface of the electron emitting device, alignment of these electrodes was difficult, especially in multi-type electron emitting devices that emit multiple electron beams. was difficult.

[Means for Solving the Problems] An electron emitting device according to the present invention includes an electron emitting source and an accelerating electrode provided at its electron emitting port, wherein the accelerating electrode the insulator is provided on the source via an insulator, the insulator has the electron emission opening formed therein, and the thickness T of the insulator from the electron emission surface of the electron emission source to the accelerating electrode; , the diameter of the electron emission aperture substantially satisfies the relational expression T≧5L.

[Operation] Since the electrons emitted from the electron emission source travel through the electron emission aperture, they do not spread beyond the diameter of the electron emission aperture, and each time they are accelerated by the acceleration electrode, a sufficiently fine electron beam is generated. Can be applied to the target surface.

[Example] Hereinafter, an example of the present invention will be described in detail based on the drawings.

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

In the figure, an electron emitting hole 2 having a diameter is formed in an insulator 1 having a thickness T, and the electron emitting hole 2 has a diameter of 〒≧5L, as described later.
It has an elongated shape that satisfies the following.

Further, an accelerating electrode 3 is formed on an insulator l on one side of the electron emission port 2, and an insulator 1) on the other side includes a metal layer 4 of NiHA, AI, etc., an insulator Pt5 of AI203, Au, etc. The metal layer 8 of the old M (Metal-Ins
It constitutes an electron-emitting device of the ulatar-Metal type. Note that the portion of the insulating layer 5 that contributes to electron emission is
It is formed thinner than other parts.

An electric field is formed within the electron emission port 2 due to the potential difference between the accelerating electrode 3 and the metal layer 4, but near the exit, the electric field distribution is such that the electron beam is diverged. Therefore, it is necessary to make the electron emission aperture 2 sufficiently long to accelerate the electrons and reduce the influence of the electric field distribution near the exit. Since the length near the exit of the electron emission port 2 is approximately the same as the diameter of the electron emission port 2, the length T of the electron emission port 2 is
If it is more than double, electrons can be accelerated upward and the influence of electric field distribution near the exit can be reduced.

Further, in order to apply a high acceleration voltage between the acceleration t[pole 3 and the metal layer 4, it is desirable that the thickness L of the insulating layer 1 satisfies the above conditions.

As a specific example, a glass l with a thickness of 1 m and a diameter L
= 1 pm electron emission "]2 is formed, and further glass 1
An AI accelerating electrode 3 is placed on one side of the , and an A1 layer 4 is placed on the other side.
, an AI203 layer 5 and an Au layer 8 are formed.

By setting the shape of the electron emission aperture 2 in this way, electrons emitted from the surface of the metal layer 4 are accelerated by the accelerating electrode 3, but the electron beam is It is released without spreading further.

Furthermore, since the insulator l is thick, a high accelerating voltage can be applied to the accelerating electrode 3, and the electron emission efficiency can also be improved by the Schottky effect.

FIG. 2 is a schematic cross-sectional view of a second embodiment of the invention.

As shown in the figure, the electrostatic lens 7 may be configured by forming a plurality of accelerating electrodes on the electron emitting side of the insulator 1. By providing the electrostatic lens 7, the electron beam emitted from the electron emission aperture 2 can be further focused, and the fine electron beam can be applied to a target at a desired position.

FIG. 3 is a schematic diagram showing an example of the use of the first embodiment of the present invention.

As shown in the figure, a bias voltage Vbt is applied to the HIM type electron-emitting device poles 4 and 6, and an accelerating voltage Vb2 is applied to the accelerating electrode 3 with respect to the electrode 4. Fine electron beam (here 1g)
m or less) is emitted, and a minute electron beam can be applied to the semiconductor wafer 8 placed sufficiently close to the semiconductor wafer 8.

FIG. 4 and FIGS. 5(A) to 5(G) are explanatory diagrams showing a method for manufacturing an electron-emitting device according to the present invention.

First, as shown in Fig. 4, an insulator 1 having a thickness τ and having a diameter-sized electron emitting hole 2 formed thereon is immersed in molten metal FJ, 9 such as A1. Depending on the wettability of the body 1, metal layers as shown in FIGS. 5(A) to 5(C) can be obtained.

FIG. 5A shows a case where a convex portion of molten metal 8 is formed within the electron emission opening 2, and a field emission type electron emission device can be constructed using this metal layer 10 as an electrode.

That is, by applying a high voltage between the electrode IO and the accelerating electrode 3, a high electric field can be concentrated near the top of the convex portion of the metal layer 10, and electrons can be emitted.

FIG. 5(B) shows a case where a flat metal layer 11 is formed in the electron emission aperture 2. In FIG. In this case, if the metal layer So, A
By vapor-depositing a metal such as u, the HIM type electron-emitting device shown in the first and second embodiments can be formed.

As shown in FIG. 5(C), even when the metal layer 12 having a valley shape inside the electron emitting opening 2 is formed, a MIX type electron-emitting device may be formed in the same manner as shown in FIG. 5(B).

After forming the electron emission source on one surface of the insulator 1 in this way, the accelerating electrode 3 is formed on the other surface to complete each of the above embodiments.

In each of the above embodiments, MIM type and field emission type elements are shown as electron emission sources, but it goes without saying that an avalanche breakdown type device of a PM junction, a surface conduction type device, or a forward bias applied to a PM junction “electron emission source” is used. An electron emission source may also be used as an electron emission source.

[Effects of the Invention] As described above in detail, the electron emitting device according to the present invention is such that the thickness T of the insulator and the diameter of the electron emitting opening substantially satisfy the relational expression T≧5L. Because of this structure, the electrons emitted from the electron emission source do not spread beyond the diameter of the electron emission aperture, and a sufficiently fine electron beam can be applied to the target surface.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view of a first embodiment of an electron emission device according to the present invention, FIG. 2 is a schematic cross-sectional view of a second embodiment of the present invention, and FIG. 3 is a schematic cross-sectional view of a second embodiment of the present invention. 4 and 5 (A) to (C) are explanatory views showing a method for manufacturing an electron-emitting device according to the present invention. 1... Insulator 2... Electron emission port 3... Accelerating electrode 4.8... Metal layer 5... Insulating layer 7... Electrostatic lens 8... Semiconductor wafer 3... Molten metal 10.11.12...Metal layer agent Patent attorney Jo Yamashita Taira $2 plan 3rd, 8 Figure 43 Figure 5

Claims (1)

[Claims] (1) In an electron-emitting device having an electron-emitting source and an accelerating electrode provided at its electron-emitting port, the accelerating electrode is provided on the electron-emitting source with an insulator interposed therebetween, and the insulator includes the An electron emission aperture is formed, and the thickness T of the insulator from the electron emission surface of the electron emission source to the accelerating electrode and the diameter L of the electron emission aperture substantially satisfy the relation T≧ An electron emitting device characterized by satisfying 5L.