JPH05182581A - Field emission type electron emission source element - Google Patents

Abstract

PURPOSE:To reduce dispersion of characteristics of a field emission type electron emission source element and reduce the operating voltage of the element by laying a first insulating layer, a first electrode layer, a second insulating layer and a second electrode layer in sequence on a substrate, and providing a groove which passes through the layers from the first insulating layer to the second electrode layer. CONSTITUTION:A first insulating layer 11, a first field application electrode layer 12, a second insulating layer 13, an electron emitting electrode layer 14, a third insulating layer 15, a second field application electrode layer 16 and an insulating portion 17 are laid on a silicon substrate 10 in that order. Each of the insulating layers is formed of silicon dioxide and each of the electrode layers is formed of tungsten. Further, a groove passing through all of the layers separates two multilayer portions from each other. The insulating portion 17 is so formed to cover the first insulating layer 11, the first field application electrode layer 12, the second insulating layer 13, the electron emitting electrode layer 14, the third insulating layer 15 and the second field application electrode layer 16 except portions of the layers which face the groove 18. Therefore, the thin film of each of the layers can be uniformly formed with good reproducibility while film thickness is ontrolled. Since the distance between the first and second electrode layers can be controlled by the film thickness of the second insulating layer, operating voltage can be reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a field emission type electron emission source device which emits electrons according to the principle of field emission.

[0002]

2. Description of the Related Art An integrated vacuum tube having a field emission type cathode structure is disclosed in, for example, C.I. A. Spinto (CASpindt)
U.S. Pat. No. 3,789,471. The element structure of these devices is basically based on a cathode which is an electron emitting portion and a gate electrode which has a role of applying an electric field to the cathode to emit electrons from the cathode. In the field emission type cathode, one means for reducing the operating voltage is to reduce the distance between the cathode and the gate electrode in order to increase the effective electric field strength applied to the cathode. At present, a widely known element is C.I.
A. US Patent 3,783 to CASpindt et al.
9, 471 and H. F. Gray (HF Gray)
Employs the structure found in U.S. Pat. No. 4,307,507.

Referring to FIG. A. Spinto (CASpin
FIG. 3 is a block diagram of a basic field emission type electron emission source device proposed by dt) and the like.

In this field emission type electron emission source device, a cathode 33 which is a cone-shaped electron emission portion is formed on a substrate electrode 30 formed of a metal or a semiconductor material, and the substrate electrode 30 around the cathode 33 is formed. A gate electrode 32 is stacked on top of the insulating layer 31. In such a configuration,
When a voltage is applied between the cathode 33 and the gate electrode 32,
During that time, a high electric field is generated, and electrons are emitted from the tip of the cathode 33 according to the principle of field emission.

Next, the manufacturing process of this element will be described with reference to FIG.

As shown in FIG. 1A, an insulating layer 31a (eg, silicon dioxide SiO ₂ ) and a gate electrode layer 32a are sequentially formed on the surface of a semiconductor (eg, silicon) substrate 30. Next, as shown in FIG. 8B, the gate electrode layer 32
A resist is applied on a, a desired pattern is baked on the resist film, a developing process is performed, a resist pattern is provided, and the gate electrode layer is exposed only in a predetermined region. Then, the gate electrode layer 32a and the insulating layer 31 exposed on the surface are formed.
When a and a are sequentially removed by means such as etching, the minute apertures 35 shown in FIG. 8C are formed on the semiconductor substrate. Then, by evaporating a metal material perpendicularly to the apertures 35, a conical cathode 33 serving as an electron emitting portion is formed on the semiconductor substrate 30 as the aperture diameter is reduced, as shown in FIG. .. By removing the metal layer 33a remaining on the surface of the gate electrode 32 by the lift-off method and removing the resist layer 34, the field emission type electron emission source device shown in FIG. 8E is obtained. Usually, a plurality of field emission type electron emission source elements are formed in an array on the same substrate.

[0007]

In this type of structure, the distance between the cathode and the gate electrode is determined by the size of the holes formed in the initial resist pattern. Therefore, in order to manufacture a plurality of electron emission source elements with good reproducibility and uniformly, it is necessary to improve the accuracy of the lithography process and the etching process. However, these techniques are greatly influenced by the device performance, and their control is not easy. That is, there is a problem that variations in the electron emission characteristics of each element due to variations in the cathode shape and the distance between the cathode and the gate electrode due to miniaturization cannot be avoided in manufacturing. Also,
Within the scope of the state of the art, the minimum diameter of the aperture and the height of the cathode are about 1 μm at the manufacturing limit. Therefore, the distance between the cathode and the gate electrode cannot be easily shortened. It is difficult to reduce the voltage).

Therefore, the present invention provides a field emission type electron emission source device having a small variation in characteristics and a small operating voltage.

[0009]

According to the present invention, a substrate, a first insulating layer laminated on the substrate, and a first electrode layer laminated on the first insulating layer are provided. A second insulating layer laminated on the first electrode layer, a second electrode layer laminated on the second insulating layer, a first insulating layer and a first electrode layer And penetrating the second insulating layer and the second electrode layer,
A field emission type electron emission source device having a groove as an electron emission space is provided.

[0010]

For example, when voltage V1 is applied to the first electrode layer and voltage V2 is applied to the second electrode layer so that V1> V2,
Electrons are emitted from the second electrode layer based on the principle of field emission. Further, for example, the first laminated layer of one of the two laminated layers composed of the first insulating layer, the first electrode layer, the second insulating layer, and the second electrode layer divided by the groove The voltage V1 is applied to the electrode layer, the voltage V2 is applied to the second electrode layer, and the voltage V3 is applied to the second electrode layer of the other laminated portion separated by the groove, V1>
When applied so that V2 and V3> V2, electrons are emitted from the second electrode layer based on the principle of field emission, and the second electrode layer to which the voltage V3 is applied becomes a triode that operates as an anode.

[0011]

Embodiments of the field emission type electron emission source device according to the present invention will be described with reference to the drawings.

FIG. 1 is a sectional view of an embodiment of a field emission type electron emission source device according to the present invention, FIG. 2 is a plan view of the device of FIG.
FIG. 3 is a sectional view of the element taken along the line BB in FIG. 1 is a sectional view taken along the line AA of FIG.

As shown in FIG. 1, on a silicon substrate 10, a first insulating layer 11 made of silicon dioxide, a first electric field applying electrode layer 12 made of tungsten (W),
A second insulating layer 13 made of silicon dioxide, an electron emission electrode layer 14 made of tungsten, a third insulating layer 15 made of silicon dioxide, a second electric field applying electrode layer 16 made of tungsten, and The insulating portion 17 is laminated in this order. Further, the first insulating layer 11, the first
The groove penetrating the electric field applying electrode layer 12, the second insulating layer 13, the electron emitting electrode layer 14, the third insulating layer 15, the second electric field applying electrode layer 16, and the insulating portion 17 of First insulating layer 11, first electric field applying electrode layer 12, second insulating layer 1
3, two layered portions including the electron emission electrode layer 14, the third insulating layer 15, the second electric field applying electrode layer 16, and the insulating portion 17 are separated from each other. The insulating portion 17 includes the first insulating layer 11, the first electric field applying electrode layer 12, and the second insulating layer 1.
3, the electrode layer 14 for electron emission, the third insulating layer 15, and the second
2 is formed so as to cover the part formed of the electric field applying electrode layer 16 except the part facing the groove 18 as shown in FIGS.

In such a laminated structure facing each other with the grooves 18 having a minute interval, a voltage V1 is applied to the electron emitting electrode layer 14 which is an electron emitting portion, and a first electric field applying electrode layer which is an electric field applying electrode. When the voltage V2 is applied to 12 and the second electric field applying electrode layer 16 so that V1 <V2, electrons are emitted from the tip of the electron emitting electrode layer 14 based on the principle of field emission. Further, the voltage V1 is applied to the electron emission electrode layer 14 which is the electron emission portion, the voltage V2 is applied to the first electric field application electrode layer 12 and the second electric field application electrode layer 16 which are the electric field application electrodes, and the groove 18 is separated. The voltage V3 is applied to the electrode layer 14b, which is a laminate made of the same material as the electron emission electrode layer 14 facing the electron emission electrode layer 14, and V1 <V2, V1 <V.
When applied so as to be 3, the electron emitting electrode layer 14 operates as a cathode, the first electric field applying electrode layer 12 and the second electric field applying electrode layer 16 operate as gate electrodes, and the electrode layer 14b operates as an anode. A function as a triode can be added. In this case, the electrode layer 1 separated by the groove 18
No voltage is applied to 2b and 16b. However, like the electrode layer 14b, it is also possible to operate as an anode by applying a voltage of about voltage V3 to the electrode layers 12b and 16b.

Next, a method of manufacturing the field emission type electron emission source device of the above embodiment will be described with reference to the drawings.

FIG. 4 is a manufacturing process drawing of the field emission type electron emission source device shown by using a side sectional view of the field emission type electron emission source device according to this embodiment shown in FIG. 1, and FIG. Three
FIG. 6 is a manufacturing process of the field emission type electron emission source device shown in the side sectional view of the field emission type electron emission source device according to the present example shown in FIG. FIG. 6 is a plan view showing a manufacturing process of. The drawings in FIGS. 4 to 6 correspond to each other.

On a silicon (Si) substrate 10, a silicon dioxide layer 11a which becomes a first insulating layer, a tungsten layer 12a which becomes a first electric field applying electrode layer, a silicon dioxide layer 13a which becomes a second insulating layer, A tungsten layer 14a that serves as an electron emission electrode layer, a silicon dioxide layer 15a that serves as a third insulating layer, and a tungsten layer 16a that serves as a second electric field applying electrode layer are deposited in this order by a sputtering apparatus to form the tungsten layer 16a. A resist film 19 is applied on the surface by a spinner. The laminated structure manufactured by this is shown in FIG. 4 (A), FIG. 5 (A) and FIG. 6 (A). At this time, the silicon dioxide layers 11a and 1 to be the insulating layers
The thickness of 3a and 15a is about 0.3 to 0.5 .mu.m, and the thickness of the tungsten layers 12a, 14a and 16a to be electrode layers is about 0.2 to 0.4 .mu.m. After that, a pattern is printed on the resist film, and the pattern shown in FIG.
A resist pattern 1 as shown in FIGS. 6B and 6B.
9a is obtained.

FIG. 5C and FIG. 6C are views in which the edge portion formed of the laminated layers exposed after the formation of the resist pattern is etched by the dry etching method. After performing the etching process, a silicon dioxide film 17a having a thickness of about 0.3 to 0.5 μm was formed on the entire surface of the tungsten layer 16a and the substrate 10 by a sputtering device. This is shown in FIG. 4 (D) and FIG.
6D and FIG. 6D. The above steps are performed in order to maintain the electrical insulation at the edge portion during the operation of the device.
After these steps are completed, the step for producing an electron emitting portion is started. First, FIG. 4 (E), FIG. 5 (E) and FIG.
As shown in (E), a desired resist pattern 20 is formed on the surface of the silicon dioxide film 17a using a resist. Next, the exposed portion is sequentially etched to the surface of the substrate by a dry etching method to obtain a structure in which the groove 18 is formed as shown in FIGS. 4 (F) and 6 (F).
After that, the resist pattern 20 remaining on the surface is removed by ashing to remove the resist pattern 20 shown in FIGS.
A field emission type electron emission source element shown in (G) is obtained.

As described above, since the field emission type electron emission source device according to the present embodiment is manufactured by the above manufacturing method, the thin films of the electrode layer and the insulating layer are uniformly and reproducibly formed while controlling the film thickness. can do. Further, in the structure of this element, since the distance between the first electrode layer and the second electrode layer can be controlled by the film thickness of the second insulating layer which is the intermediate layer,
It is also possible to achieve a reduction in operating voltage.

In this embodiment, only one element is shown, but normally, a plurality of field emission type electron emission source elements are formed in an array on the same substrate. Further, although tungsten is used as the electrode material, the present invention is not limited to this, and an electrode having a similar structure can be realized by using another metal such as molybdenum (Mo).

[0021]

As described above, the field emission type electron emission source device according to the present invention includes a substrate, a first insulating layer laminated on the substrate, and a first insulating layer laminated on the first insulating layer. A first electrode layer, a second insulating layer laminated on the first electrode layer, a second electrode layer laminated on the second insulating layer, a first insulating layer Since the insulating layer, the first electrode layer, the second insulating layer, and the second electrode layer are penetrated, and the groove as the electron emission space is provided, the thin film of each layer is made uniform while controlling the film thickness. And can be formed with good reproducibility. Further, in the structure of this element, since the distance between the first electrode layer and the second electrode layer can be controlled by the film thickness of the second insulating layer which is the intermediate layer,
It is also possible to achieve a reduction in operating voltage.

[Brief description of drawings]

FIG. 1 is a sectional view of an essential part of an embodiment of a field emission type electron emission source device according to the present invention.

FIG. 2 is a plan view of an essential part of an embodiment of a field emission type electron emission source device according to the present invention.

3 is a sectional view taken along line BB of FIG.

FIG. 4 is a manufacturing process diagram of the field emission type electron emission source element shown by using the side sectional view of the field emission type electron emission source element according to the present embodiment shown in FIG.

5A and 5B are manufacturing process diagrams of the field emission type electron emission source device shown by using a side sectional view of the field emission type electron emission source device according to the present embodiment shown in FIG.

FIG. 6 is a manufacturing process diagram of the field-emission electron emission source device shown by using the plan view of the field-emission electron emission source device according to the present embodiment shown in FIG. 2;

FIG. 7 is a cross-sectional view of a main part of a conventional vertical field emission type electron emission source device.

FIG. 8 is a manufacturing process diagram of a conventional vertical field emission electron emission source device.

[Explanation of symbols]

 10 Silicon Substrate 11 First Insulating Layer 12 First Electric Field Applying Electrode Layer 13 Second Insulating Layer 14 Electron Emitting Electrode Layer 15 Third Insulating Layer 16 Second Electric Field Applying Electrode Layer 17 Insulating Part 18 Groove

Claims (1)

[Claims] 1. A substrate, a first insulating layer laminated on the substrate, a first electrode layer laminated on the first insulating layer, and a first electrode layer on the first electrode layer. A laminated second insulating layer,
A second electrode layer laminated on the second insulating layer, the first insulating layer, the first electrode layer, the second insulating layer, and the second electrode layer are penetrated. And a field-emission electron emission source element having a groove as an electron emission space.