JPH0797475B2 - Electron-emitting device - Google Patents

Description

TECHNICAL FIELD The present invention relates to an electron-emitting device, and more particularly to an electron-emitting device in which electron emission is induced by voltage application. Such an electron-emitting device is preferably used as an electron generation source of an electron beam application device such as various electron beam exposure devices.

[Prior Art] Thermionic emission from a hot cathode has hitherto been used as an electron source in an electron beam apparatus such as a cathode ray tube.
Electron emission using such a hot cathode is said to have a large energy loss due to heating, the need to form a heating means, the time required for preheating to a considerable extent, and the system being easily destabilized by heat. There was a problem in terms.

Therefore, research on an electron-emitting device that does not rely on heating has been advanced, and several types of devices have been proposed.

For example, a type in which a reverse bias voltage is applied to a PN junction to generate an electron avalanche phenomenon and electrons are emitted to the outside of the element, or a metal-insulator layer-metal layer structure is used to A type (MIM type) that emits electrons that have passed through the insulator layer from the metal layer to the outside of the element by applying a voltage between them, or a direction perpendicular to the thickness direction of the high resistance thin film A voltage is applied to a surface conduction type that emits electrons from the surface of the thin film to the outside of the element, or a metal having a shape where electric field concentration easily occurs to locally generate a high-density electric field. A field effect type (FE type) that emits electrons from a metal to the outside of the element and other types have been proposed.

[Problems to be Solved by the Invention] Of these, the MIM type electron-emitting device has a feature that an applied voltage may be relatively low and a vacuum degree that is not so high is required.

FIG. 3 is a perspective view showing an example of a conventionally proposed MIM type element.

In FIG. 3, 2 is an insulating substrate, 4 is a first metal layer, 6 is an insulator layer, and 8 is a second metal layer. As shown in the drawing, the upper surface of the substrate 2 is flat, and the first metal layer 4 having a predetermined width is arranged on the flat surface so as to extend in the first direction. The insulator layer 6 is the substrate 2
And a substantially uniform thickness so as to cover the first metal layer 4 arranged so as to project on the surface thereof. Therefore, a portion corresponding to the first metal layer 4 also projects on the upper surface of the insulator layer 6. A second metal layer 8 having a predetermined width is arranged on the upper surface of the insulator layer 6 so as to extend in a direction substantially orthogonal to the first direction.

Means for timely applying a voltage between the first metal layer 4 and the second metal layer 8 so that the second metal layer 8 becomes positive.
10 are connected. The means 10 has a power source and a switch (not shown).

Thus, the MIM structure is formed at the position where the first metal layer 4 and the second metal layer 8 overlap each other, and the other metal layer portions are used as lead wires. By arranging a plurality of such electron-emitting devices in the first direction and the second direction and sharing the first metal layer 4 and the second metal layer 8, so-called matrix-driving electrons can be obtained. A discharge device can be constructed.

However, in such a conventional MIM type element, since the insulator layer 6 and the second metal layer 8 are formed on the non-planar base, the insulator layer 6 and the second metal layer 8 are formed especially at the MIM structure position. The thickness of the metal layer 8 is likely to be non-uniform, which tends to deteriorate the element characteristics, and even when a plurality of elements are arranged so as to be matrix-driven, there is a large variation in the characteristics of each element. There was a problem that it was a win.

Further, in the conventional element, since the second metal layer 8 is formed in a vertically wavy curved shape, the length thereof is relatively long, which results in a large electric resistance and a large amount of heat generation. There was also.

[Means for Solving the Problems] According to the present invention, in order to solve the above-mentioned problems of the prior art, a first metal layer is provided on an insulating substrate, and the first metal layer is formed on the metal layer. An insulator layer is provided, and a second metal layer is provided on the insulator layer, and means for applying a voltage between the first metal layer and the second metal layer is provided. In an electron-emitting device having the first metal layer, the first metal layer is embedded in a recess formed in the base, and an insulator is formed on a substantially flat surface formed by the upper surface of the first metal layer and the upper surface of the base. An electron-emitting device is provided, which is characterized in that a layer is formed.

[Examples] Specific examples of the present invention will be described below with reference to the drawings.

FIG. 1 (a) is a perspective view showing an embodiment of the electron-emitting device according to the present invention, and FIG. 1 (b) and FIG. 1 (c) are BB sectional view and CC sectional view, respectively. It is a figure.

In these figures, 2 is an insulating substrate, which is, for example, glass, alumina, sapphire, mica, magnesia, GaAs, GaSb, InAs, GaP, spinel (MgAl ₂
It consists of crystals such as O ₄ ). A groove 3 having a predetermined width and depth extending along the CC direction is formed on the upper surface of the substrate 2.

Reference numeral 4 is a first metal layer, 6 is an insulator layer, and 8 is a second metal layer, which form a MIM structure.

As shown, the first metal layer 4 has two grooves 3 in the substrate 2.
Are arranged so that the upper surface of the metal layer 4 and the upper surface of the substrate 2 are substantially flush with each other. The first metal layer is, for example, Al, Be, Mo, Pt, Ta, Au, Ag, W, Cr, Mg,
It consists of nichrome. The metal layer 4 may be a layer made of an alloy containing some of these metals or a layer made of these silicides. The thickness of the metal layer 4, that is, the depth of the groove 3 is not particularly limited, but is, for example, about 0.001 to 1 μm. The width of the metal layer 4, that is, the width of the groove 3 is not particularly limited and can be appropriately set according to a desired electron emission area, but is, for example, about 0.001 to 5 μm.

The insulator layer 6 is made of, for example, SiO ₂ , Ta ₂ O ₅ , Al ₂ O ₃ , BeO, SiC, SiO _x N.
_y H _z , SiN _x H _y , phosphorus case glass (PSG), AlN, SiO ₂ .BN
Etc. As shown, the insulator layer 6 is substantially flat. The thickness of the insulator layer 6 is preferably as small as possible so as not to cause dielectric breakdown, but this thickness is not limited to that of the metal used for the second metal layer 8 of the type of insulator used for the layer 6. It is preferable to appropriately set the desired electron emission characteristics according to the type and the like, and for example, about 30 to 1000 Å.

The second metal layer 8 is made of the same material as the first metal layer 4. As shown, the second metal layer 8 is substantially linear. The thickness of the metal layer is preferably as thin as possible from the viewpoint of electron emission efficiency, and is, for example, about 100 to 3000 Å. The width of the metal layer 8 is not particularly limited and can be set appropriately according to the desired electron emission area.
For example, it is about 0.001 to 5 μm.

As shown in FIG. 1, means 10 for applying a timely voltage is connected between the first metal layer 4 and the second metal layer 8 so that the second metal layer 8 becomes positive. Has been done. The means 10 has a power source and a switch (not shown).

The electron-emitting device of this embodiment as described above can be manufactured, for example, as follows.

First, the surface of the material of the substrate 2 is made to have sufficiently good flatness and surface roughness by physical polishing or chemical polishing, a photoresist is applied to the surface of the substrate 2, and the above-mentioned resist layer is formed by pattern exposure and development. The portion corresponding to the portion where the groove 3 is to be formed is removed, and then the groove 3 is formed on the surface of the substrate 2 by the wet etching method. When the substrate 2 is glass, a mixed solution of hydrofluoric acid, nitric acid, acetic acid, or pure water is used as an etching solution.

Next, the metal material forming the first metal layer 4 is made almost equal to the depth of the groove 3 by resistance heating evaporation method, electron beam evaporation method, CVD method, plasma CVD method, ion plating method, cluster ion beam method, or the like. Films are formed to have the same thickness, and then the resist layer is dissolved and removed, and the metal material film other than in the groove 3 is removed by lift-off, thus forming the first metal layer 4.

Next, the insulator layer 6 is formed on the upper surface of the first metal layer 4 by a resistance heating vapor deposition method, an electron beam vapor deposition method, a CVD method, a plasma CVD method, an ion plating method, a cluster ion beam method or the like.

Next, a second metal layer 8 is formed on the insulator layer 6 by a resistance heating vapor deposition method, an electron beam vapor deposition method, a CVD method, a plasma CVD method, an ion plating method, a cluster ion beam method or the like. The second metal layer 8 needs to be patterned, which can be done by usual photolithographic techniques.

Thereafter, the voltage applying means 10 is connected between the first metal layer 4 and the second metal layer 8.

The thus-produced element of the present embodiment is driven by voltage applying means.
This is done by closing 10 switches. The voltage of the power source of the voltage applying means can be appropriately set according to the specific configuration of the MIM structure and the desired electron emission characteristics, and is, for example, 3 to 20V. By applying a voltage between the first metal layer 4 and the second metal layer 8 as described above, electrons are emitted from the surface of the second metal layer 8.

2 (a) to 2 (c) show an embodiment of an electron emitting device in which a large number of electron emitting devices according to the present invention are arranged, and FIG. 2 (a) is a partial plan view. FIG. 2 (b) and FIG. 2 (c) are the BB sectional view and CC, respectively.
FIG.

In the present embodiment, 2 is a substrate, and a plurality of grooves 3 having a predetermined width and depth in the CC direction are arranged in parallel at regular intervals on the substrate surface. Then, the first metal layer 4 is embedded in each groove 3. 6 is an insulator layer, and the insulator layer is substantially flat. A plurality of second metal layers 8 having a predetermined width in the BB direction are arranged on the insulator layer 6 at regular intervals.

The substrate 2, the first metal layer 4, the insulator layer 6 and the second metal layer 8 are made of the materials described in the embodiment of FIG.

The apparatus of this embodiment is produced in the same manner as described with reference to the embodiment of FIG.

Although not shown in FIG. 2, in order to apply a voltage such that the second metal layer side is positive between the first metal layers 4 and the second metal layers 8 at appropriate times. Means are connected. Therefore, in the device of this embodiment, MI is set at a position where each first metal layer 4 and each second metal layer 8 overlap each other.
Since the M structure is formed, the MIM structure at a desired position can be appropriately driven by so-called matrix driving.

[Effect of the Invention] According to the present invention as described above, since the first metal layer forming the MIM structure is embedded in the substrate, the insulator layer and the second metal layer are both flat, Therefore, the insulator layer and the second metal layer can be accurately formed in a desired shape and size, and an electron-emitting device excellent in uniformity of characteristics is provided.

Further, according to the present invention, since the second metal layer is linear, the length can be made relatively short, and therefore the electric resistance of the second metal layer can be made relatively small and the heat generation can be reduced. The amount can also be reduced.

Further, since the element of the present invention has a flat outer surface, it is less likely to be damaged even if it comes into contact with other objects during handling.

[Brief description of drawings]

FIG. 1 (a) is a perspective view of the electron-emitting device, and FIGS. 1 (b) and 1 (c) are a BB sectional view and a CC sectional view, respectively. FIG. 2A is a partial plan view of the electron emission device.
FIG. 2B and FIG. 2C are a BB sectional view and a CC sectional view, respectively. FIG. 3 is a perspective view of the electron-emitting device. 2: substrate, 3: groove 4, 8: metal layer, 6: insulator layer, 10: voltage applying means.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Akira Suzuki 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Isamu Shimoda 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Incorporated (72) Inventor Masahiko Okunuki 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (56) References Japanese Patent Publication Sho 49-7383 (JP, B1)

Claims (1)

[Claims] 1. A first metal layer is provided on an insulating substrate, an insulator layer is provided on the metal layer, and a second metal layer is provided on the insulator layer. In the electron-emitting device having means for applying a voltage between the first metal layer and the second metal layer, the first metal layer is embedded in the recess formed in the substrate. The electron-emitting device is characterized in that an insulator layer is formed on a substantially flat surface formed by the upper surface of the first metal layer and the upper surface of the base body.