JPS634532A - electron-emitting device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electron-emitting device, and particularly to an electron-emitting device in which electron emission is induced by application of a voltage. Such an electron-emitting device is suitably used as an electron generation source in a device using a semiconductor beam, such as a Katsura electron beam exposure device.

[Prior Art] Conventionally, thermionic emission from a hot cathode has been used as an electron generation source in an electron beam device, such as a cathode ray tube.

Electron emission using such a hot cathode has the disadvantages that there is a large energy loss due to heating, that it is necessary to form a heating means, that it takes a considerable amount of time for preheating, and that the system is easily destabilized by heat. There was an f1 question.

Therefore, research into electron-emitting devices that do not rely on heating is progressing, and several types of devices have been proposed.

For example, when PNjf<, a reverse bias voltage is applied to cause an avalanche breakdown phenomenon and electrons are emitted to the outside of the device.
There is a type (MIM type) in which electrons that have passed through an insulator layer are emitted from the metal layer to the outside of the element by applying a voltage between two metals due to the tunnel effect, and a high-resistance thin film that is Surface conduction type devices that emit electrons from the surface of the thin film to the outside of the device by applying a voltage in orthogonal directions, or metals with shapes that tend to cause electric field concentration, can generate a locally high-density electric field by applying a voltage. A field effect type (FE type) type in which electrons are generated and electrons are emitted from the metal to the outside of the element, and other types have been proposed.

[Problems to be Solved by the Invention] Among these, the MIMfi electron-emitting device has the advantage of requiring only a relatively low applied voltage and not requiring a very high degree of vacuum.

As mentioned above, in MIM type electron-emitting devices, gold!
Electrons are emitted from the surface of the A layer, and ideally the electron emission is performed randomly so that the electron emission distribution is uniform over the entire surface as a time average. However, the conventionally proposed MIM5! In a device, the electron emission distribution may become non-uniform or fluctuate due to subtle local non-uniformity in the thickness of the insulator layer and the metal layer applied thereon. For this reason, there has been a problem in that it is difficult to obtain an electron beam having desired energy characteristics when accelerating or deflecting the emitted electrons.

[Means for Solving the Problems] According to the present invention, in order to solve the problems of the prior art as described above, an insulating layer is provided on the metal, and a metal layer is formed on the insulating layer. In an electron-emitting device having means for applying a voltage between the two metals, the metal below the insulator layer forms a closed loop of the ridge line at the boundary with the insulator layer. An electron-emitting device is provided, which is characterized in that it has a shape of .

[Example] Specific examples of the present invention will be described below with reference to the drawings.
Do J+.

FIG. 1(a) is a partial plan view showing one embodiment of the electron-emitting device according to the present invention, and FIG. 1(b) is a partial plan view of the electron-emitting device according to the present invention.
It is an i-side view.

In FIG. 1, reference numeral 2 denotes an insulating substrate, which is made of, for example, glass, alumina, sapphire, mica, magnesia, or crystals such as GaAs, GaSb, InAs, GaP, and spinel (MgA 1204 ).

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

The first metal layer is, for example, A1. Be, Mo.

Pt, Ta, Au, Pd, Ag, W, Cr, Mg.

Made of nichrome etc. The metal layer 4 may be a layer made of an alloy containing some of these metals or a layer made of silicide of these metals. As shown in the figure, the metal layer 4 has a truncated cone shape, and its A circular ridge line 5 is formed as an intersection line between the side surface and the top surface. The thickness of the metal layer 4 (that is, the height of the truncated cone shape) is not particularly limited, but is, for example, about 0°001-1 pm. The money f! The width of the layer 4 (that is, the diameter of the truncated cone shape) is not particularly limited and can be appropriately set depending on the desired electron emission area, and is, for example, about o, ooi to 5 μm.

The insulator layer 6 is made of, for example, Si02 or Ta205.

Al2O3, BeO, SiC, SiON H.

x y z SiN H, phosphorus silicate glass (PSG).

y Consists of AIN, BN, etc. The thickness of the insulator layer 6 is preferably as thin as possible to prevent dielectric breakdown, but this thickness depends on the type of insulator used for the layer 6 and the metal used for the second metal layer 8. It is preferable to set it appropriately so as to obtain the desired electron emission characteristics depending on the type, etc., for example, 1O~2
The second metal layer 8, which has a thickness of about 0,000 to 2,000, is made of the same material as the first metal layer 4. The thickness of the metal layer 8 is preferably as thin as possible from the viewpoint of electron emission efficiency, and is, for example, 100 to 300 mm thick.
It is about 08.

As shown in FIG. 1(b), a means is provided for applying a voltage at appropriate times 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).

The electron-emitting device of this example as described above can be produced, for example, in the following manner.

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, and then the surface of the substrate 2 is coated with resistance heating evaporation method, electron beam evaporation method, CVD method,
The metal material constituting the first metal layer 4 is formed into a single layer by a plasma CVD method, an ion blating method, a cluster ion beam method, or the like.

Next, a photoresist 7 is applied thereon, and the portion of the resist layer corresponding to the portion other than the portion where the first metal layer 4 is to be formed is removed by pattern exposure and development, and then wet etching is performed. Remove the exposed metal material. By over-etching and undercutting during this etching, a metal layer 4 having a truncated conical shape is formed. Further, instead of the wet etching method, a dry etching method can be used, but in this case, the metal layer 4 having a substantially truncated conical shape is formed by lowering the degree of vacuum during etching.

Next, an insulating layer is formed on the upper surface of the first metal layer 4 and the upper surface of the substrate 2 by a resistance heating evaporation method, an electron beam evaporation method, a CVD method, a plasma CVD method, an ion blating method, a cluster ion beam method, etc. form 6.

Next, the second metal layer 8 is formed on the insulator layer 6L by a resistance heating evaporation method, an electron beam evaporation method, a CVD method, a plasma CVD method, an ion blating method, a cluster ion beam method, or the like.

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

The device of this embodiment thus produced is driven by closing the switch of the voltage application means 10. The voltage of the power source of the voltage applying means can be appropriately set depending on the specific configuration of the MIM structure and 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, electrons are mainly supplied from the vicinity of the ridge line 5 of the first metal layer 4, and as shown in FIG.
As shown in b), it is emitted diagonally. That is,
The electric field strength increases because the ridgeline 5 in the first gold gs layer 4 is convex and the insulator layer 6 corresponding to the ridgeline 5 is thin due to step coverage. metal! ! ! This is because the portion of 8 corresponding to the ridge line 5 is also thin due to step coverage, so that the electron emission efficiency is increased. From this, the emitted electrons are given an initial velocity approximately along the conical surface that has the point S as the apex and passes through the ridgeline 5, and behaves as if the point S is the limit of generation, so the emitted electrons are deflected or accelerated. When doing so, desired control can be performed extremely accurately.

In this embodiment, the first metal G4 has a truncated cone shape in which the top surface is smaller than the bottom surface, but the same effect can be obtained even if the first metal G4 has a truncated cone shape, a cylindrical shape, etc. in which the top surface is larger than the bottom surface. Furthermore, in the above embodiment, the ridge line 5 of the metal layer 4 of ml
Although the shape is circular, other shapes are also acceptable in the present invention. For example, when the shape of the first metal layer 4 in the above embodiment is a regular polygonal truncated pyramid shape or a regular polygonal prism shape, a linear ridgeline is used as the intersection line between the top surface and the side surface of the metal layer 4. A regular polygonal closed loop consisting of a set is formed, and the present invention also includes such a case. Further, depending on the purpose, the closed loop may have an anisotropic shape such as an ellipse.

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

In this embodiment, 2 is a substrate, and a plurality of grooves 3 having a predetermined width and depth in the DD direction are arranged in parallel at regular intervals on the surface of the substrate. A first metal layer 4 is embedded in each groove 3, and the metal layer has portions 4a that protrude upward from the surface of the substrate 2 at regular intervals. The shape is the same as the metal layer 4 described with respect to FIG. 1 above. 6 is an insulator layer and a substrate? and the tenth metal bending layer 4 and its protrusion 4
It is applied to the entire surface covering a. Reference numeral 8 denotes a second metal layer in the B-B direction, which is arranged in a plurality of downward rows on the insulating layer 6 at regular intervals. In a portion of the metal layer 8 corresponding to the metal layer protrusion 4a, a planar bulge 8a corresponding to the protrusion is formed.

Substrate 2, first metal layer 4, insulator layer 6 and second metal layer 8 are made of the materials described in connection with the embodiment of FIG. 1 above.

The device of this embodiment is constructed in a manner similar to that described with respect to the embodiment of FIG. 1 above.

That is, first, the surface of the material of the substrate 2 is made to have good flatness and surface roughness upward by physical polishing or chemical research, and a photoresist is applied to the surface of the substrate 2, and then patterned by exposure and development. A portion of the resist layer 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 wet etching. If the substrate 2 is made of glass, a mixed solution of fluoride, nitric acid, acetic acid, or pure water is used as the etching solution.

Next, a metal material constituting the first metal layer 4 is deposited using a resistance heating evaporation method, an electron beam evaporation method, a CVD method, a plasma CVD method, an ion blating method, a cluster ion beam method, etc., to a depth approximately equal to the depth of the groove 3. The resist layer is formed to have the same thickness, and then the resist layer is dissolved and removed, and the metal material film outside the groove 3 is removed by lift-off, thus forming the first metal layer 4 excluding the protrusion 4a.

Next, the protrusion 4a is formed in the same manner as the metal layer 4 in the embodiment shown in FIG. 1, and then the insulator layer 6 and the second metal layer 8 are formed. However, in the case of the device of this embodiment, the second metal layer 8 needs to be patterned. This patterning can be performed using conventional photolithography techniques.

Although not shown in FIG. 2, a voltage is applied at appropriate times between each first metal layer 4 and each second metal layer 8 so that the second metal layer side is positive. means are connected. Therefore, in the device of this embodiment, at the position where each first metal layer 4 and each second metal layer 8 overlap, that is, at the position t of the protruding portion 4a and the bulging portion 8a, in the embodiment shown in FIG. This means that an MIM structure such as t is formed, and a desired number of MIM structures t can be appropriately driven by so-called matrix driving.

[Effects of the Invention] According to the present invention as described above, since the metal on the electron supply side constituting the MIM structure has a shape with a closed loop of ridge lines at the boundary with the insulating layer, desired and stable electron supply can be achieved. An electron-emitting device capable of realizing an emission distribution is provided, thus making it easy to accurately control emitted electrons.

[Brief explanation of drawings]

FIG. 1(a) is a partial plan view of an electron-emitting device, and the first
Figure (b) is the BB sectional view. FIG. 2(a) is a partial plan view of the electron-emitting device, and the second
FIG. 2(b), FIG. 2(C), and FIG. 2(d) are a BB sectional view, a CC sectional view, and a DD sectional view, respectively. ? =Substrate, 3: Groove 4.8: Metal layer, 4a: Protrusion, 5: Edge line, 6: Insulator layer, 8a: Swelling part, 10: Voltage application means. Agent Patent Attorney Hiratsu Yamashita

Claims (2)

[Claims] (1) An electron-emitting device comprising an insulating layer on a metal, a metal layer on the insulating layer, and means for applying a voltage between the two metals. characterized in that the metal below the insulating layer has a shape with a closed loop of ridge lines at the boundary with the insulating layer,
Electron-emitting device. (2) The electron-emitting device according to claim 1, wherein the closed loop has a regular polygonal shape or a circular shape.