JPH0794078A - Field emitting chip - Google Patents

Abstract

PURPOSE:To improve the integration density of elements by constituting a field emitting chip from a base bottom part and a plurality of electron beam emitting parts provided on the base bottom part CONSTITUTION:A first silicon nitride film is formed on both surfaces of a monocrystal silicon base, and the silicon nitride film is removed in square form to form a groove having a square bottom. An etching groove is then oxidized to provide an oxide film, a groove form having four cavities is provided on the bottom part, and a second silicon nitride film is further formed on both surfaces of this sample. A second base material is connected to the groove- formed surface side of the sample, and after the first and second silicon nitride films are removed, the first base material and the silicon oxide film are eluted, whereby a second silicon nitride film is exposed in the groove form having four cavities. Thereafter, a film of a metal material having a small work function such as cesium is formed on the field emitting chip side, whereby a form having four electron beam emitting parts 11 on a base bottom part 12 is provided. Thus, the integration with double density, compared with in the past, can be performed, and integration density of elements can be improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a field emission tip of a micro electron source used for a vacuum integrated circuit, a micro vacuum tube for microwave / millimeter wave, a display element, an electron source for electron beam exposure, and the like.

[0002]

2. Description of the Related Art With the progress of semiconductor manufacturing technology, technical developments related to vacuum microelectronics have been activated. This technology, whose basic element is to radiate an electron beam from a field emission tip, has a high carrier speed, is capable of refraction, focusing and diffraction, has no scattering in a medium, has no influence of temperature and radiation, and has a material It has attracted widespread attention because it has remarkable advantages such as freedom of choice and high degree of structural freedom.

A field emission tip, which is a main device for achieving this technique, is manufactured by using an oblique vapor deposition method or an etching method. The shape was a cone or a quadrangular pyramid having one apex (protrusion).
The apex (projection) of the cone or the quadrangular pyramid serves as an electron beam radiating portion, from which the electron beam is radiated. Then, the field emission tips manufactured in this manner are integrated and used for a screen display element and a calculation element.

[0004]

However, the conventional field emission tip has only one electron beam emitting portion (projection) with respect to one bottom surface (base portion) of the field emission tip. There is a problem that it cannot be integrated in high density. The present invention has been made in view of the above problems, and an object thereof is to provide a field emission tip capable of improving the integration density.

[0005]

As a result of earnest research, the inventor has realized that the integration density can be improved by providing a plurality of electron beam emitting portions (projections) for one field emission tip. . That is, the field emission tip of the present invention is constituted by "a base portion and a plurality of electron beam emitting portions provided in the base portion (claim 1)".

[0006]

The field emission tip of the present invention has a plurality of electron beam emitting portions, so that the integration density can be improved.
Hereinafter, the present invention will be described in more detail with reference to Examples.
The present invention is not limited to this.

[0007]

2 is a schematic view showing a manufacturing process of a highly integrated field emission tip according to a first embodiment of the present invention. First
A first silicon nitride film 22 is formed on both surfaces of a 100-crystal-oriented single crystal silicon substrate 21 having a thickness of 250 μm, which is a substrate material, by low pressure vapor deposition. After that, the silicon nitride film 22 is removed into a quadrangular shape having a side of about 10 μm by using a dry etching method. The silicon nitride film 22 is removed, and the exposed portion of the silicon substrate 21 is anisotropically etched. Thus, a groove having a square bottom (100 faces) was formed (Fig. 2a). When this groove is viewed from above, it becomes as shown in FIG. 3a.

After that, the etching groove is oxidized to form the oxide film 23.
Was set up. At this time, the growth rate of the oxide film becomes slower at the corners of the groove (the vertices of the quadrangle at the bottom of the groove).
A groove shape with two depressions is obtained (Fig. 2b). A second silicon nitride film 24 was formed on the front and back surfaces of this sample by the low pressure vapor deposition method (FIG. 2c).

A second substrate material 25 is formed on the groove forming surface side of this sample.
And the first silicon nitride film 22 and the second silicon nitride film 24 on the back surface are removed by dry etching. Then, the entire sample is dipped in an alkaline aqueous solution such as a KOH aqueous solution or a TMAH aqueous solution to immerse the first substrate material 21 and the silicon oxide film 2.
Elute 3. By doing so, the second silicon nitride film 24 is exposed in the form of a groove having the above-mentioned four depressions (2
(Fig. d).

Then, a metal material 26 having a small work function such as cesium is formed on the side of the field emission tip by vacuum deposition or the like.
Was deposited (FIG. 2e). The metal material 26 preferably has a small work function, and thus cesium is used in this embodiment, but the material is not limited to this. In this way, a plurality of field emission tip groups having four protrusions at the tip were formed. The shape of the field emission tip is a shape having four electron beam emission parts 11 on the base part 12 as shown in 1b of FIG.

FIG. 4 shows a group of field emission tips (4
It is a top view which compared the conventional field emission tip group (FIG. 4b) with FIG. The size of the base of each field emission tip is a square shape of about 10 μm square. The black circles in the figure represent the tips of the protrusions (electron beam emitting portions). When a display element composed of these field emission tip groups was produced, a display element having a density four times higher than that of the conventional display element could be obtained. As described above, it was revealed that the field emission tip of the present invention improves the integration density of devices.

A method of manufacturing a field emission tip according to the second embodiment of the present invention will be described with reference to FIG. A first silicon nitride film 22 was formed on both surfaces of a 100-oriented single crystal silicon substrate 21 having a thickness of 250 μm, which is a first substrate material, by a low pressure vapor deposition method. Then, a large number of nitride films having a width of about 10 μm and a length of 5 μm were partially removed by a dry etching method, and the silicon substrate 21 was anisotropically etched to form a groove having a ridge line at the bottom. (2a
Figure). The shape of this groove is as shown in FIG.

Then, the etching groove was oxidized to form an oxide film 23 (FIG. 2b). At this time, the growth rate of the oxide film was slowed at the corners of the groove (two apexes of the groove bottom), so that a groove shape having two depressions at the bottom was obtained. A second silicon nitride film 24 was formed on this sample by a low pressure vapor deposition method.
Was formed on the front and back surfaces (Fig. 2c).

A second substrate material 25 is formed on the groove forming surface side of this sample.
And the first silicon nitride film 22 and the second silicon nitride film 24 on the back surface are removed by dry etching. Then, the entire sample is dipped in an alkaline aqueous solution such as a KOH aqueous solution or a TMAH aqueous solution to immerse the first substrate material 21 and the silicon oxide film 2.
Elute 3. By doing so, the second silicon nitride film 24 is exposed in the shape of the groove having the above-mentioned two depressions (2
(Fig. d).

After that, a metal material 26 having a small work function such as cesium was formed on the tip side by a vacuum vapor deposition method or the like (FIG. 2e). The metal material 26 preferably has a small work function, and thus cesium is used in this embodiment, but the material is not limited to this. In this way, a plurality of tip groups having two needle-like protrusions at the tip were formed.

The field emission tip has a shape having two electron beam emitting portions 11 on a base 12 as shown in 1a of FIG. In addition, it has become possible to integrate at a density twice as high as that of the conventional field emission tip. As described above, it was confirmed that the integration density of the device is improved by using the field emission tip having a plurality of electron beam emission parts for one base part.

Further, similar to the first and second embodiments, when a groove is formed in the first substrate 21, the electron beam emitting portions are provided in a number corresponding to the number of vertices of the shape of the bottom of the groove. Field emission tips can be made. That is, the integration density can be improved according to the number of vertices. Further, when the field emission tip is manufactured as in this example,
Since a plurality of field emission tips can be produced at one time, the device can be easily and efficiently integrated.

[0018]

The field emission tip of the present invention can improve the integration density of devices.

[Brief description of drawings]

1 is a schematic view showing a field emission tip according to an embodiment of the present invention, FIG. 1a shows a field emission tip having two electron beam emitting portions, and FIG. 1b shows a field emission tip having four electron beam emitting portions. Indicates a tip.

FIG. 2 is a schematic view showing a method of manufacturing a field emission tip according to an embodiment of the present invention.

FIG. 3 is a schematic view showing a method of manufacturing a field emission tip according to an embodiment of the present invention.

FIG. 4 shows a group of field emission tips according to an embodiment of the present invention (4
It is a top view which compared the conventional field emission tip group (FIG. 4b) with FIG.

[Explanation of symbols]

 11 ... Electron Beam Emitting Part 12 ... Base Part 21 ... First Substrate Material 22 ... Silicon Nitride Film 23 ... Silicon Oxide Film 24 ... Silicon Nitride Film 25 ... Second Substrate materials 26 ... Metal materials

Claims (1)

[Claims] 1. A highly integrated field emission tip comprising a base and a plurality of electron beam emitters provided in the base.