JPH04167325A - Field emission type emitter - Google Patents

Abstract

PURPOSE:To reduce manufacturing cost and to stabilize electron emission by providing a first insulating material formed on a glass substrate, a conductor film formed thereon, a second insulating film, a cavity, a cathode and a gate electrode. CONSTITUTION:A first insulating film 2 is formed on a glass substrate, and a conductor film 3 thereon, a second insulating film 4 formed on the film 3 and/or the film 2, and a cavity 4a formed thereon are provided. A cathode 5 formed on the conductor film 3 inside the cavity 4a and a gate electrode 7 formed on the film 4 are provided. If a glass substrate is used, electron emission from a cathode becomes unstable because of a problem of unstable electric potential caused by unstableness on a surface of the glass substrate. Forming of the film 2 on the substrate 1 and the forming of the cathode 5 thereon via the conductor film 3, however, can stabilize electron emission from the cathode 5.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a field emission type emitter, and is suitable for application to a flat display such as a flat CRT.

[Summary of the invention]

The present invention provides a field emission emitter that includes a glass substrate, a first insulating film formed on the glass substrate, a conductive film formed on the first insulating film, and a conductive film and/or a first insulating film formed on the first insulating film.
a second insulating film formed on the insulating film, a cavity formed in the second insulating film, a cathode formed on the conductive film inside the cavity, and a second insulating film formed on the second insulating film. and a gate electrode. This makes it possible to reduce the manufacturing cost of field-emission emitters, support larger areas such as flat displays using field-emission emitter arrays, and reduce the risk of cracking or warping of the substrate. Moreover, the instability of electron emission from the cathode due to the problem of undefined potential on the surface of the glass substrate can be solved.

[Conventional technology]

Conventionally, as a field emission type emitter having a size on the order of microns, one called a Spind type as shown in FIG. 6 has been known.

As shown in FIG. 6, in this field emission type emitter, a silicon dioxide (SiO□) film 102 with a thickness of about 1 μm is formed on a conductive silicon (Si) substrate 101. A cavity 102a is formed in this 5sozl 1102. Then, on the Si substrate 101 inside this cavity 102a, molybdenum (M
A conical cathode 103 with a pointed tip is formed of a metal with a high melting point and a low work function, such as O) or tungsten (W).

Furthermore, a gate electrode 104 made of a high melting point metal such as Mo, W, or chromium (Cr) is formed on the Si substrate 101 around the cavity 102a. here,
The diameter of the opening of this gate electrode 104 directly above the cathode 103 is about 1 μm.

The field emission type emitter shown in FIG. 6 has a gate electrode 1
By applying an electric field of about 106 V/C11 or more between the cathode 103 and the cathode 103, electrons can be emitted without heating the cathode 103. According to such a field emission type emitter having a size on the order of microns, the gate voltage may be on the order of several tens to hundreds of square meters.

Note that the electron emission from the cathode 103 is 1O-6Tor.
Since it is necessary to carry out the process in a vacuum of about r or less, the above-mentioned field emission type emitter is actually vacuum-sealed with a counter plate and other members (not shown).

[Problems to be Solved by the Invention] The conventional field emission type emitter shown in FIG.
Since the substrate 101 is used, there are the following drawbacks. That is, since the maximum diameter of the Si substrate 101 that can be obtained at present is about 10 inches, there are restrictions on the area of the Si substrate 101 that can be used. For this reason, it is not possible to cope with an increase in the area of a flat display such as a flat CRT using a field emission type emitter array.

Further, even though the Si substrate 101 is the cheapest among semiconductor substrates, it is still expensive, which increases the manufacturing cost of the field emission type emitter.
Since 01 is generally thin, there is a high risk of cracking or warping.

Accordingly, an object of the present invention is to provide a field emission type emitter that can be used to increase the area of a flat display using a field emission type emitter array.

Another object of the present invention is to provide a field emission type emitter that can reduce manufacturing costs.

Another object of the present invention is to provide a field emission type emitter in which the risk of cracking or warping of the substrate is reduced.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a field emission emitter that includes a glass substrate (1) and a glass substrate (1).
) formed on the first insulating film (2), the conductor 11W (3) formed on the first insulating film (2), and the conductor film (3) formed on the first insulating film (2).
) and/or the second insulating film (4) formed on the first insulating film (2), the cavity (4a) formed in the second insulating film (4), and the cavity (4a). It includes a cathode (5) formed on an internal conductor film (3) and a gate electrode (7) formed on a second insulating film (4).

Specific examples of the first insulating film (2) include a silicon dioxide (SiOz) film and a silicon nitride (SiN) film.

[Effect]

According to the field emission type emitter of the present invention configured as described above, since an inexpensive glass substrate is used, the manufacturing cost of the field emission type emitter can be reduced. In addition, since a glass substrate with a large area can be easily obtained, it can be easily applied to a large-area flat display such as a flat CRT using a field emission type emitter array. Furthermore, the glass substrate is S
There is less risk of cracking or warping compared to i-boards.

On the other hand, when a glass substrate is used, there is a problem in that electron emission from the cathode becomes unstable due to the problem of unstable potential caused by instability of the surface. However, according to the field emission type emitter of the present invention, the first insulating film is formed on the glass substrate, and the cathode etc. are formed on the first insulating film through the conductor film, so that electron emission from the cathode is stabilized. can be made to do so.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a field emission type emitter according to a first embodiment of the invention.

As shown in FIG. 1, in the field emission type emitter according to the first embodiment, for example, 530g of
An insulating film 2 such as a film, SiN, or a film is formed. On this insulating film 2, for example, Cr or aluminum (AI) is used.
A line-shaped conductor film (cathode line) 3 made of a metal such as the like is formed.

Reference numeral 4 indicates an insulating film such as a 530g film with a film thickness of about 1 μm. A cavity 4a having, for example, a circular planar shape is formed in this insulating film 4. and,
A conical cathode 5 with a pointed tip is formed on the conductor film 3 inside the cavity 4a and is made of a metal with a high melting point and a low work function, such as Mo or W.

Further, on the insulating film 4 around the cavity 4a, for example, tungsten silicide (WS) is applied via a polycrystalline Si film 6.
A gate electrode 7 made of a high melting point metal silicide such as molybdenum silicide (MoSi, ) or molybdenum silicide (MoSi, ) is formed to surround the cathode 5.

Here, the film thickness of the polycrystalline St film 6 is, for example, 500 to 10
Approximately 00 people. Further, the film thickness of the high melting point metal silicide film, for example, the WSiX film forming the gate electrode 7 is, for example, 0. It is 2 to 0.5 μm. Here, this W
The Si composition ratio X of Si is preferably 2.4 to 2.4, for example.
Selected within the range of 2.8. When X is within this range, W Si and the internal residual stress during film formation are minimized. Furthermore, if x>2, W S i ,t
When W is oxidized, Sin is likely to be formed, and therefore the oxidation of W can be effectively suppressed.

Further, the gate electrode 7 and the cathode 5 of the polycrystalline Si film 6
The diameter of the opening directly above is, for example, about 1 μm.

Further, in the field emission type emitter according to the first embodiment, as in the conventional field emission type emitter described above, the gap between the gate electrode 7 and the cathode 5 is approximately 10'V/C1.
By applying an electric field of about 1 or more, electrons can be emitted without heating the cathode 5, and a gate voltage of about several 10 to 100 μ is sufficient. Also, cathode 5
Since electron emission from the emitter must be performed in a vacuum of about 10-'' Torr or less, the field emission type emitter according to the first embodiment is actually vacuum-sealed with a counter plate and other members (not shown). Ru.

Next, a method of manufacturing the field emission type emitter according to the first embodiment configured as described above will be explained.

As shown in FIG. 2A, first, for example, C.
Insulated by VD method! ! 2, this insulating film 2
A conductor film such as a metal film is formed thereon by sputtering, for example. Next, this conductor film is patterned into a predetermined shape to form a line-shaped conductor Wi3. Next, an insulating film 4, a polycrystalline Si film 6, and a high melting point metal silicide film 8 such as a W Si film are sequentially formed over the entire surface by, for example, the CVD method. Next, a resist pattern 9 having a shape corresponding to the gate electrode to be formed is formed on this high melting point metal silicide film 8 by lithography.

Next, using resist pattern 9 as a mask, high melting point metal silicide film 8 and polycrystalline Si film 6 are sequentially etched by wet etching or dry etching. As a result, as shown in FIG. 2B, a gate electrode 7 is formed and the polycrystalline Si film 6 is patterned to have the same shape as the gate electrode 7.

Next, resist pattern 9, gate electrode 7 and polycrystalline S
Using the i film 6 as a mask, the insulating film 4 is coated with hydrogen fluoride (H
Etching is performed by a wet etching method using a type F) etching solution to form a cavity 4a as shown in FIG. 2C. In addition, this wet etching
It is also possible to perform this after removing the resist pattern 9.

Next, after removing the resist pattern 9, as shown in the second diagram, for example, aluminum (A1) or nickel (Ni) is deposited on the gate electrode 7 by oblique vapor deposition from a direction inclined to the substrate surface. A release layer 10 is formed. Thereafter, a cathode forming material such as MoJpW is deposited from a direction perpendicular to the substrate surface. As a result, the cathode 5 is formed on the conductor film 3 inside the cavity 4a. Reference numeral 11 indicates a metal film deposited on the release layer 10.

Thereafter, the peeling layer 10 and the metal film 11 formed thereon are removed by a lift-off method to complete the desired field emission type emitter as shown in FIG.

As described above, according to the first embodiment, a glass substrate l is used, which is cheaper than a Si substrate, has less risk of cracking or warping, and can easily be made with a large area. , the manufacturing cost of field emission emitters can be reduced, and the manufacturing yield of field emission emitters can be improved by reducing the risk of warping or cracking of the substrate. The present invention can easily be applied to larger areas such as flat displays such as flat CRTs.

Furthermore, the problem of instability of electron emission from the cathode 5 due to the undefined potential on the surface of the glass substrate 1 can be solved by forming an insulating film 2 on the glass substrate 1 and forming the cathode 5 on it with a conductive film 3 interposed therebetween. This can be solved by

Further, according to this first embodiment, the gate electrode 7 is W S
Since the gate electrode 7 is made of a high melting point metal silicide that is difficult to oxidize, such as iX, the gate electrode 7 is not oxidized during the manufacturing process, and therefore, it is possible to prevent the electrical conductivity of the gate electrode 7 from decreasing due to oxidation. . Thereby, electron emission from the cathode 5 can be performed stably.

Further, deformation of the gate electrode 7 due to oxidation can be prevented. Moreover, since the high melting point metal silicide, which is the material of the gate electrode 7, is formed by the CVD method, the internal residual stress of the gate electrode 7 can be alleviated by controlling the 5ill composition ratio X of the high melting point metal silicide. Therefore, deformation of the gate electrode 7 can also be prevented by this. Furthermore, by forming polycrystalline 5tH6 between the gate electrode 7 and the insulator I14, it is possible to improve the adhesion of the gate electrode 7 to the base.

This can effectively prevent the gate electrode 7 from peeling off from the underlying layer due to deformation. Also, W.S.
Refractory metal silicides such as i x are chemically stable and have good chemical resistance, and are therefore convenient for manufacturing.

Further, as shown in FIG. 3, by forming a plurality of line-shaped conductor films 3 in parallel with each other and arranging a plurality of cathodes 5 linearly on each conductor film 3, the cathode 5 can be connected to each conductor film 3. It can be driven every time.

The field emission type emitter according to the first embodiment is suitable for use in, for example, a large-area flat CRT.

FIG. 4 shows a field emission type emitter according to a second embodiment of the invention.

As shown in FIG. 4, in the field emission type emitter according to the second embodiment, the gate electrode 7 is formed of a high melting point metal such as W, Mo, or Cr, or lanthanum boride (LaB6). This embodiment differs from the field emission type emitter according to the first embodiment in that the polycrystalline Si film 6 is not formed. The rest of the configuration is the same as that of the first embodiment, so a description thereof will be omitted.

According to the second embodiment, since the glass substrate 1 is used, the manufacturing cost of the field emission type emitter can be reduced, and the field emission type emitter array can be used for flat displays such as flat CRTs. For large area
This can be easily handled, and the risk of cracking or warping of the board can be reduced.

FIG. 5 shows a field emission type emitter according to a third embodiment of the invention.

As shown in FIG. 5, the field emission type emitter according to the third embodiment is similar to the field emission type emitter according to the first embodiment, except that a conductive film 3 is formed on the entire surface of the insulating WA2. It has a configuration.

According to this third embodiment, as described in the first embodiment,
Advantages of using the glass substrate 1 can be obtained.

Although the embodiments of the present invention have been specifically described above, the present invention is not limited to the above-described embodiments, and various modifications can be made based on the technical idea of the present invention.

For example, the cavity 4a in the first, second, and third embodiments described above is formed by wet etching, but this cavity 4a is formed by, for example, reactive ion etching (RIE). It is also possible to form by an anisotropic etching method such as. When this anisotropic etching method is used, a cavity 4a having side walls substantially perpendicular to the substrate surface is formed.

Further, in the first embodiment and the third embodiment, the high melting point metal silicide which is the material forming the gate electrode 7 can also be formed by, for example, a sputtering method.

〔Effect of the invention〕

As described above, according to the present invention, since a glass substrate is used, it is possible to reduce the manufacturing cost of field emission type emitters, and it is possible to increase the area of flat displays, etc. using field emission type emitter arrays. It is possible to reduce the risk of cracking or warping of the substrate.

Furthermore, since the first insulating film is formed on the glass substrate, there is no instability in electron emission from the cathode due to the problem of undefined potential on the surface of the glass substrate.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing a field emission type emitter according to a first embodiment of the present invention, and FIGS. 3 is a perspective view showing an arrangement example of a line-shaped conductive film formed on a glass substrate and a cathode thereon, and FIG. 4 is a cross-sectional view showing a field emission type emitter according to a second embodiment of the present invention. 5 is a sectional view showing a field emission type emitter according to a third embodiment of the present invention, and FIG. 6 is a sectional view showing a conventional field emission type emitter. Explanation of main symbols in the drawings] Glass substrate, 2.4: insulating film, 3: conductor film, 4a: cavity, 5: cathode, 7: gate electrode. Agent Patent Attorney Tadashi Sugiura Chi No. 7 Poverty 1 Figure 4 Figure 3 Example Figure 5

Claims (1)

[Scope of Claims] A glass substrate, a first insulating film formed on the glass substrate, a conductive film formed on the first insulating film, and the conductive film and/or the first insulating film formed on the first insulating film.
or a second insulating film formed on the first insulating film; a cavity formed in the second insulating film; and a cathode formed on the conductive film inside the cavity; and a gate electrode formed on the insulating film of No. 2.