JPH08306302A - Field emission electron source and manufacturing method thereof - Google Patents

Abstract

(57) [Abstract] [Purpose] It can be easily manufactured by a normal photolithography process and a semiconductor process, and has a sharp emitter electrode without using a lift-off process, and also has an emitter electrode and a gate electrode. (EN) Provided is a field emission type electron source in which the distance between and can be controlled with submicron accuracy. [Structure] On a conductive substrate 10 made of a metal or a semiconductor, a lower surface 12 and a higher surface 13 are provided via a step portion 11.
Are formed, and the linear protrusion 14 having an acute cross section formed between the high surface 13 and the step portion 11 serves as a cathode. A high electrode 16A is formed on the high surface 13 via a high insulating film 15A, and a low electrode 16B is formed on the low surface 12 via a low insulating film 15B. There is. When a positive electric field with respect to the cathode is applied to either one of the upper electrode 16A and the lower electrode 16B,
Electrons are emitted from the linear protrusion 14 that is the cathode.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a field emission electron source which is a cold electron source expected to be applied to a self-luminous flat display element, an ultra-high speed micro vacuum element, an electron beam excited solid-state laser, or the like. In particular, the present invention relates to a field emission electron source which is excellent in compatibility with existing semiconductor processes such as silicon and the uniformity of elements, and which can realize integration and low voltage.

[0002]

2. Description of the Related Art Advances in fine processing technology for semiconductors have made it possible to form minute field emission electron sources. Spindt et al. Proposed a cone-type (vertical) field emission electron source, and a minute field emission electron source has been attracting attention (Reference 1: CA Spindt, J. Appl. Phys. Vol. 39). ,
p.3504 (1986)).

As the first conventional example, the structure and manufacturing method of the field emission type electron source proposed by Spindt will be described below with reference to FIG.

First, as shown in FIG. 13A, an insulating layer 102 and a gate electrode 103 made of a metal are sequentially formed on a conductive substrate 101 made of silicon, and then the gate electrode 103 and the insulating layer 102 are formed into a circular shape. The small hole 104 is formed by a normal photolithography process.

Next, as shown in FIG. 13B, a sacrificial layer 105 made of alumina or the like is deposited on the conductive substrate 101 at a shallow angle. Through this step, the gate diameter is reduced and the gate electrode 103 is covered with the sacrificial layer 105.

Next, as shown in FIG. 13C, a metal 106 such as molybdenum, which will be an emitter electrode, is formed on the conductive substrate 1.
01 is vapor-deposited from the vertical direction. By doing so, the gate opening becomes smaller as the vapor deposition progresses, so that the cone-shaped emitter electrode (cathode) 10 is provided inside the small hole 104.
7 is formed.

Next, as shown in FIG. 13D, the sacrificial layer 105 is lifted off by wet etching to remove the unnecessary metal 106.

This field emission electron source has a gate electrode 10
3 operates by drawing electrons from the tip of the emitter electrode 107 into a vacuum and receiving the drawn electrons by an anode electrode (anode) (not shown) provided so as to face the emitter electrode 107.

Further, the emitter electrode having a vertical structure similar to that of the first conventional example and having a sharper tip shape is formed by using crystal anisotropic etching or anisotropic dry etching of silicon and thermal oxidation. A method has been proposed (reference 2: HFGray et al., IEDM Tech.Dig.p.776, (1986)), and reference 3: Bekei, 1990 Autumn Simplified Studies, SC- 8-2 (1990)).

The structure and manufacturing method of the field emission electron source proposed by Bei, et al. As a second conventional example will be described below with reference to FIG.
Will be described with reference to.

First, as shown in FIG. 14A, a silicon oxide film 112 is formed on a conductive substrate 111 made of silicon.
Then, a photolithography process is performed on the silicon oxide film 112 to form a disk-shaped etching mask 113 as shown in FIG. 14B.

Next, dry etching is performed on the conductive substrate 111 using the etching mask 113 under conditions involving side etching, so that the tip is formed below the etching mask 113 as shown in FIG. 14C. A three-dimensional body 114 having a thin portion is formed. After that, the three-dimensionally shaped body 114 is subjected to thermal oxidation, so that the three-dimensionally shaped body 1 is obtained.
14 is changed to a structure including a cone-shaped body 115 made of silicon inside and a thermal oxide film 116 outside.

Next, as shown in FIG. 14D, silicon oxide to be the insulating film 117 and metal to be the gate electrode 118 are vacuum-deposited from the direction perpendicular to the surface of the conductive substrate 111. , The peripheral portion of the etching mask 113 on the conductive substrate 111 and the etching mask 113.

Next, the conductive substrate 111 is immersed in an aqueous solution of hydrofluoric acid to remove the thermal oxide film 116 around the cone-shaped body 115 and lift off the etching mask 113 to which the insulating film and the metal film are attached. 14E, an emitter electrode made of the cone-shaped body 115 is formed as shown in FIG. 14E, and a field emission type electron source having a structure similar to the Spindt type can be obtained.

Like the first conventional example, this field emission electron source is provided so that electrons are drawn into a vacuum from the tip of the emitter electrode 115 by the gate electrode 118 and the extracted electrons are opposed to the emitter electrode 115. It operates by being received by an anode electrode (anode) (not shown).

On the other hand, a planar field emission electron source has also been proposed (Reference 4: Ito et al., Vol.
(P.867 (1991)), in this plane type electron source, since the emitter electrode, gate electrode, anode electrode, etc. can be formed on the same substrate, the degree of freedom regarding the device structure and the like are large and the capacitance is small. For this reason, application to ultra-high speed devices is expected.

As a third conventional example, a planar structure field emission electron source shown in Reference 4 will be described below with reference to FIG.
This will be described with reference to FIGS.

As shown in FIG. 15, the field emission type electron source of the third conventional example is a conductive substrate 121 made of quartz and a strip-shaped gate electrode 12 formed on the conductive substrate 121.
2A and an emitter electrode 123A made of a comb-shaped metal foil formed so as to face the gate electrode 122A.

The field emission type electron source according to the third conventional example is manufactured as follows. That is, as shown in FIG. 16A, after a W film 123B to be an emitter electrode is deposited on a conductive substrate 121 made of quartz, as shown in FIG. 16B, the resist pattern 124 is used as a mask to form the W film. 123B is processed into a predetermined shape by RIE. After that, as shown in FIG. 16C, the conductive substrate 121 is etched with an aqueous solution of hydrofluoric acid.

Next, after the metal film 122B to be the gate electrode is vacuum-deposited, as shown in FIG. 16D, the metal film 122B attached on the resist pattern 124 is lifted off. Thereafter, as shown in FIG. 16E, after forming a resist pattern 125 by a photolithography process, the metal film 1 is formed using the resist pattern 125 as a mask.
22B is wet-etched to form the gate electrode 122A. After that, FIG.
As shown in (f), after forming a resist pattern 126 by a photolithography process, the resist pattern 1 is formed.
By performing wet etching on the W film 123B using 26 as a mask, the emitter electrode 1 having a comb shape is formed.
23A is formed. Then, when the resist pattern 126 is removed, a field emission type electron source having a planar structure as shown in FIG. 16G is completed.

Further, the present inventor has previously proposed a field emission electron source having a cocktail glass structure having a planar structure using a silicon substrate (Reference 5: Hori et al., IEICE Tech. ED94-95, p. 1
(1994-12)). A field emission electron source formed on a silicon substrate can be integrated with an LSI or the like, and new applications can be expected.

As a fourth conventional example, a field emission type electron source having a planar structure having a cocktail structure formed on a silicon substrate, shown in Reference 5, will be described with reference to FIG.

First, as shown in FIG. 17A, a silicon oxide film is formed on the surface of a conductive substrate 131 made of silicon, and then the silicon oxide film is etched to obtain a submicron aperture. Dot mask 13
2 is produced. After that, the conductive substrate 131 is dry-etched using the dot mask 132, so that the conductive substrate 131 is removed as shown in FIG.
Columnar structure 13 made of silicon perpendicular to the surface of the
3 is formed.

Next, anisotropic etching is applied to the side surface of the columnar structure 133, so that as shown in FIG. 17C, an inverted truncated cone shape having a crystal plane including the (331) plane as a side surface. 17 after forming a cocktail glass-like structure composed of an upper part 134A of the above and a lower part 134B having a truncated cone shape.
As shown in (d), a metal film 135 to serve as a gate electrode and an insulating film 136 are vacuum-deposited on the cocktail glass structure.

Next, the conductive substrate 131 is immersed in an aqueous solution of hydrofluoric acid and the dot mask 132 is lifted off to remove the insulating film 136 and the metal film 135 attached on the dot mask 132. As shown in e), a cocktail glass type field emission electron source that emits electrons from the edge portion 137 of the upper portion 134A of the emitter electrode composed of the upper portion 134A and the lower portion 134B is completed.

[0026]

According to the field emission type electron sources according to the first and second conventional examples, it is possible to integrate the cone type emitter electrodes at a high density, and the emitter electrodes of the cone type emitter electrodes can be integrated. Since the radius of curvature of the tip is about 20 nm, an electron source with a low voltage and a large current can be realized.

However, according to the first conventional example, since the emitter electrode 107 is formed by vapor deposition of metal, the shape of the emitter electrode 107, especially the shape of the tip, is necessarily different between the central portion and the peripheral portion of the element. However, if the field emission type electron source has a certain area or more, there is a problem that uniform performance cannot be obtained. Further, it is necessary to lift off the sacrificial layer 105, and dust floats in the etching solution, so there is a problem that lift-off that is not used in a normal semiconductor process cannot be avoided.

According to the second conventional example, the cone-shaped body 11
Since the shape of the emitter electrode made of 5 depends on the dry etching conditions for the thermal oxide film 116, there is a problem that in-plane variations in the shape of the emitter electrode cannot be avoided. Further, since the vapor deposition method and the lift-off process are used to form the gate electrode 118, the gate electrode 11
8 has a non-uniform shape of the edge portion, and like the first conventional example, if the field emission electron source has an area larger than a certain area, uniform performance cannot be obtained, and lift-off is unavoidable. There is a problem. further,
Since the gate aperture is restricted by the resolution limit of photolithography,
There is also a problem that an expensive apparatus such as electron beam exposure or X-ray exposure must be used to reduce the voltage.

According to the third conventional example, the ordinary photolithography technique can be used, and the distance between the emitter electrode 122A and the gate electrode 123A can be easily controlled to about submicron, so that the reproducibility and uniformity of the device structure can be improved. There is a feature that it is expensive.

However, according to the third conventional example, there is a problem that the operating voltage is relatively high because the radius of curvature of the tip of the emitter electrode 122A is about 40 nm. Further, there is a problem that the vacuum deposition of the metal film 122B and the lift-off process for the resist pattern 124 cannot be avoided.

According to the fourth conventional example, an emitter electrode having a steep shape and a high reproducibility can be realized in the edge portion 137 of the upper portion 134A of the emitter electrode made of the cocktail glass structure, and the operation can be realized. It has the characteristic of low voltage.

However, the metal film 135 and the insulating film 1
There is a problem that the vacuum deposition of 36 and the lift-off process for the dot mask 132 are unavoidable.

As described above, the conventional field emission electron source has a problem that the metal vapor deposition and the lift-off process associated therewith are unavoidable.

In view of the above, the present invention can be easily manufactured by an ordinary photolithography process and a semiconductor process, and has an emitter electrode having a steep shape and a emitter electrode without using a lift-off process. It is an object of the present invention to provide a field emission electron source in which a distance from a gate electrode can be controlled with submicron accuracy and a method for manufacturing the same.

[0035]

According to a first aspect of the present invention, there is provided a field emission type electron source comprising a lower surface and a conductive higher surface formed on a substrate through a step. A high electrode that is formed on the high surface via an insulating layer, faces the cathode, and is electrically insulated from the cathode; and a high electrode that is formed on the low surface and has the cathode. Electrons are emitted from the cathode when a voltage is applied between the cathode and the lower electrode facing each other and electrically insulated from the cathode, and at least one of the upper electrode and the lower electrode. It is configured to do.

According to a second aspect of the invention, in the structure of the first aspect, the high electrode and the low electrode are electrically connected, and the high electrode and the low electrode are connected to the cathode. A configuration in which a positive voltage is applied is added.

According to a third aspect of the present invention, in the structure of the first aspect, the high electrode and the low electrode are electrically separated from each other, and the high electrode and the low electrode are mutually separated. The configuration is such that voltages are independently applied.

According to a fourth aspect of the present invention, in the structure of the third aspect, the amount or direction of electrons emitted from the cathode toward the anode is controlled by controlling the voltages applied to the upper electrode and the lower electrode, respectively. A configuration for controlling the is added.

According to a fifth aspect of the present invention, in the structure according to the third aspect, a positive constant voltage is applied to one of the high electrode and the low electrode with respect to the cathode while the high electrode is applied. By changing the voltage applied to the other electrode of the electrode and the lower electrode, a configuration is added in which the amount of electrons emitted from the cathode and directed to the one electrode is changed.

According to a sixth aspect of the present invention, in the structure according to the first aspect, the substrate is a crystalline substrate, and the cathode is formed by the crystal anisotropic etching with respect to the substrate to form the high surface and the step portion. The configuration in which the corner portion is formed at an acute angle is added.

According to the invention of claim 7, in addition to the structure of claim 6, the substrate is a crystalline substrate, and the surface of the high portion is formed on the (100) plane of the substrate. is there.

According to an eighth aspect of the present invention, in the structure according to the seventh aspect, the cathode is exposed to a (111) plane extending in a <011> direction by crystal anisotropic etching with respect to the substrate. The structure is added in the form of a line having an acute cross-sectional shape.

According to a ninth aspect of the present invention, in the structure according to the seventh aspect, the cathode extends in the <011> direction in the step portion by crystal anisotropic etching with respect to the substrate and the (111) planes orthogonal to each other are exposed. By doing so, a structure formed in a dot shape having an acute cross-sectional shape is added.

According to a tenth aspect of the present invention, a field effect electron source is provided with a plurality of lower surface portions and a plurality of lower surface portions which are formed on a substrate via step portions and are arranged linearly or in a matrix. A conductive high surface, a plurality of cathodes formed at corners of the plurality of high surfaces and the plurality of step portions, and an insulating layer formed on the plurality of high surfaces. A plurality of high electrodes facing the cathode and electrically insulated from the cathode, and formed on the plurality of lower surfaces, facing the cathode and electrically insulated from the cathode. A plurality of lower electrodes, and a plurality of the plurality of high electrodes and a plurality of lower electrodes at least one of the plurality of electrodes and the plurality of cathodes when a voltage is applied between the plurality of the plurality of electrodes. The structure is such that electrons are emitted from the cathode.

According to an eleventh aspect of the invention, in the structure of the tenth aspect, the plurality of high electrodes and the plurality of low electrodes are electrically connected to each other, and the plurality of high electrodes and the plurality of low electrodes are electrically connected. A structure in which a positive voltage is applied to the partial electrode with respect to the cathode is added.

According to a twelfth aspect of the present invention, in the structure of the tenth aspect, the plurality of high electrodes and the plurality of low electrodes are electrically separated from each other, and the plurality of high electrodes and the plurality of high electrodes are separated from each other. The configuration is such that a voltage is applied to the lower electrode independently of each other.

According to a thirteenth aspect of the present invention, in the method of manufacturing a field effect electron source, a high surface and a low surface are formed on a conductive substrate through a step portion, whereby the high surface and the high surface are formed. A cathode forming step of forming a cathode at a corner of the step and a high electrode is formed on the high surface via an insulating layer, and a low electrode is formed on the low surface via an insulating layer. And a step of forming an electrode to be formed.

According to a fourteenth aspect of the present invention, in the structure of the thirteenth aspect, the cathode forming step includes a first step of forming an etching mask having a predetermined shape on the conductive substrate, and the etching mask is used to form the etching mask. A second step of forming the step portion by etching a conductive substrate, wherein the electrode forming step is performed on the high surface and the low surface and is perpendicular to the substrate surface. A structure having a step of forming the high electrode and the low electrode by sequentially depositing an insulating material and a conductive material from different directions is added.

According to a fifteenth aspect of the present invention, in the structure of the thirteenth aspect, the cathode forming step includes a first step of forming a first etching mask having a predetermined shape on a conductive substrate, and the first etching. A second step of forming the step portion by performing etching on the conductive substrate using a mask, wherein the electrode forming step is performed on the conductive substrate via an insulating layer. A first step of forming a conductive film, a second step of forming a second etching mask having a predetermined shape on the conductive film, and a second step of forming a second etching mask on the conductive film using the second etching mask. A third step of forming the high electrode and the low electrode by etching is added.

The invention of claim 16 is the invention of claim 14 or 15.
In the second step of the cathode forming step, the corner portion having an acute cross-sectional shape is obtained by performing direction anisotropic etching from a direction inclined with respect to a direction perpendicular to the substrate surface as the etching. A configuration including a step of forming a is added.

The invention of claim 17 relates to claim 14 or 15.
In the above configuration, the conductive substrate is a crystalline substrate, and the second step in the cathode forming step is to perform the crystal anisotropic etching as the etching to remove the corner portion having an acute cross-sectional shape. A structure including a forming step is added.

The invention of claim 18 relates to claim 14 or 15.
In the above configuration, the conductive substrate is a crystalline substrate, and the second step in the cathode forming step is, as the etching, directional anisotropic etching from a direction inclined with respect to a direction perpendicular to the substrate surface. After that, crystal anisotropic etching is performed to add a configuration including a step of forming the corner portion having an acute cross-sectional shape.

The invention of claim 19 is the invention of claim 14 or 15.
In the above configuration, the conductive substrate is a substrate made of silicon, and in the cathode forming step, after the second step, the conductive substrate is heat-treated to oxidize the surface portion of the step portion. After the silicon film is formed, the silicon oxide film is removed to add a configuration having a third step of forming the corner portion into a steep sectional shape.

According to a solution of the invention of claim 20, a method for manufacturing a field effect electron source is provided, wherein an etching mask having a predetermined shape made of a silicon oxide film is formed on a conductive substrate made of silicon. And a high surface by forming a high surface and a low surface on the conductive substrate via a step portion by etching the conductive substrate using the etching mask. A second step of forming a cathode at a corner of the step and a heat treatment on the conductive substrate to form an insulating layer on each of the high surface and the low surface, and A third step of forming a silicon oxide film on the surface of the step portion, and depositing a conductive material on the conductive substrate in a direction perpendicular to the substrate surface, thereby forming a conductive material on the high surface. Insulation A fourth step of forming a high electrode through the insulating layer and a low electrode through the insulating layer, and removing the silicon oxide film formed on the surface of the step portion. By doing so, a fifth step of forming the corner portion into a steep sectional shape is provided.

[0055]

According to the structure of the present invention, since the cathode is formed at the corner between the high surface and the step of the substrate, the cathode is formed by etching the substrate. Therefore, the shape of the cathode is regulated by the etching conditions. To be done. Further, since the electrode is formed on the surface of the upper portion with the insulating layer interposed therebetween, the distance between the cathode and the upper electrode is determined by the thickness of the insulating layer which can be easily controlled. Furthermore, since the cathode is formed by etching the substrate, the cathode can be formed without using a lift-off process.

The upper electrode and the lower electrode are electrically connected,
When separately disposing the anode so as to face the cathode, by applying a voltage to one and the other electrodes at the same time and applying a voltage higher than the voltage applied to the one and the other electrodes to the anode, Most of the electrons emitted from the anode can reach the anode.

Further, when the high electrode and the low electrode are electrically separated and a positive voltage is applied to one of the high electrode and the low electrode with respect to the cathode, the low electrode Acts as an extraction electrode, and when a voltage higher than that of the one electrode is applied to the other electrode of the high electrode and the low electrode, the other electrode acts as an anode and the electrons emitted from the cathode emit the other electrode. Drive towards. Then, by changing the voltage applied to one electrode, the amount of electrons emitted from the cathode and directed to the other electrode, that is, the amount of current flowing from the anode to the cathode can be changed. When the anode is separately arranged so as to face the cathode, the amount or direction of electrons emitted from the cathode and directed to the anode can be controlled by changing the voltage applied to one electrode and the other electrode.

According to the structure of claim 6, since the cathode is formed at an angle between the upper surface and the step portion by the crystal anisotropic etching on the crystalline substrate, the cathode having an acute cross-sectional shape is crystal anisotropic. Formed by reactive etching.

According to the structure of the seventh aspect, since the upper surface is formed on the (100) plane of the crystalline substrate, the cathode having an acute sectional shape is surely formed by the crystal anisotropic etching.

According to the structure of claim 8, the upper surface is formed on the (100) plane of the crystalline substrate, and the cathode is formed on the step portion by crystal anisotropic etching of the substrate <011>.
Since the (111) plane extending in the direction is exposed, a linear cathode having an acute cross section can be realized with good reproducibility.

According to the structure of claim 9, the upper surface is formed on the (100) plane of the crystalline substrate, and the cathode is formed on the step portion by crystal anisotropic etching of the substrate <011>.
Since the (111) planes extending in the direction and orthogonal to each other are exposed, a dot-shaped cathode having an acute cross-sectional shape can be realized with good reproducibility.

According to the structure of claim 10, a plurality of lower surface portions and a plurality of conductive upper surface portions are arranged linearly or in a matrix on the substrate through the step portions, and the plurality of higher surface portions and the plurality of higher surface portions are arranged. Forming a plurality of cathodes at the corners of the step portion, forming a plurality of high-part electrodes on the plurality of high-part surfaces through an insulating layer, and forming a plurality of low-part electrodes on the plurality of low-part surfaces. Since it is formed, a single electron source including a combination of the cathode and the extraction electrode can be efficiently arranged in a straight line or a matrix.

When the upper electrode and the lower electrode are electrically connected, both the upper electrode and the lower electrode act as electron extraction electrodes, so that the amount of electrons emitted from the cathode and directed to the separately provided anode is increased. Can be increased to increase the amount of current flowing from the anode to the cathode.

When the high electrode and the low electrode are electrically separated, when one of the high electrode and the low electrode is applied with a positive voltage with respect to the cathode, the low electrode is pulled out. When a voltage higher than that of the one electrode is applied to the other electrode of the upper electrode and the lower electrode, the other electrode functions as an anode, and the electrons emitted from the cathode are directed to the other electrode. Run. Then, by changing the voltage applied to one electrode, the amount of electrons emitted from the cathode and traveling to the other electrode, that is, the amount of current flowing from the anode to the cathode can be changed. When the anode is separately arranged so as to face the cathode, the amount or direction of electrons emitted from the cathode and directed to the anode can be controlled by changing the voltage applied to one electrode and the other electrode.

According to the thirteenth aspect, the high surface and the low surface are formed on the conductive substrate through the step portion, and the cathode is formed at the corner between the high surface and the step portion. Can be formed without using a lift-off process. In addition, since the high electrode is formed on the high surface through the insulating layer,
The distance between the cathode and the upper electrode can be determined by the thickness of the insulating layer, which can be easily controlled.

According to the structure of the fourteenth aspect, since the step portion is formed by etching using the etching mask formed on the conductive substrate, the shape of the step portion can be determined by the etching conditions. Also,
Since the high electrode and the low electrode are formed by sequentially depositing the insulating material and the conductive material on the high surface and the low surface in the direction perpendicular to the substrate surface, the high electrode and the low electrode are separated by the step. The high electrode and the low electrode can be formed in a self-aligned manner.

According to the structure of the fifteenth aspect, since the step portion is formed by performing etching using the first etching mask formed on the conductive substrate, the shape of the step portion is determined by the etching conditions. You can
In addition, since the high electrode and the low electrode are formed by etching the conductive film formed on the conductive substrate via the insulating layer using the second etching mask having a predetermined shape, the high electrode is formed. The distance between the electrode and the lower electrode can be controlled by the etching mask.

According to the structure of the sixteenth aspect, since the step portion is formed by performing the direction anisotropic etching from the direction inclined with respect to the direction perpendicular to the substrate surface, the cathode having the acute sectional shape is anisotropically oriented. It can be formed by reactive etching.

According to the seventeenth aspect, since the step portion is formed by performing the crystal anisotropic etching on the crystalline substrate, the cathode having the acute sectional shape can be formed by the direction anisotropic etching. it can.

According to the eighteenth aspect, since the step portion is formed on the crystalline substrate by using the direction anisotropic etching and the crystal anisotropic etching together, a cathode having a uniform cross section can be easily and reproducibly formed. Can be realized.

According to the structure of claim 19, heat treatment is applied to the step portion of the conductive substrate made of silicon to form a silicon oxide film on the surface portion of the step portion, and then the silicon oxide film is removed. It is possible to easily realize a cathode having a steep sectional shape. According to the structure of claim 20,
Etching is performed on a conductive substrate made of silicon using an etching mask to form a high surface and a low surface on the conductive substrate through the step, so that the step, that is, the shape of the cathode is used as an etching condition. And the cathode can be formed without using a lift-off process. In addition, by depositing a conductive material on the conductive substrate in a direction perpendicular to the substrate surface, a high electrode is formed on the high surface via an insulating layer and a high electrode is formed on the low surface. Since the lower electrode is formed via the insulating layer, the upper electrode and the lower electrode can be formed in a self-aligned manner via the step portion, and the distance between the cathode and the upper electrode can be easily controlled. It can be determined by the thickness of the insulating layer. Further, after heat-treating the step portion made of silicon to form a silicon oxide film on the surface portion of the step portion, the silicon oxide film is removed, so that a cathode having a steep cross-sectional shape can be easily realized. be able to.

[0072]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Field emission type electron emission sources according to respective examples of the present invention and manufacturing methods thereof will be described below with reference to the drawings.

FIG. 1 shows the structure of a field emission electron source according to the first embodiment of the present invention. As shown in FIG. 1, a step portion is formed on a conductive substrate 10 made of metal or semiconductor. 1
1, a lower surface 12 and a higher surface 13 are formed, and a linear protrusion 14 having an acute cross section formed between the higher surface 13 and the step portion 11 serves as a cathode. . The upper electrode 1 is provided on the upper surface 13 with a high insulating film 15A interposed therebetween.
6A is formed, and the lower electrode 16B is formed on the lower surface 12 via the lower insulating film 15B.

When a positive electric field with respect to the cathode is applied to either one of the upper electrode 16A and the lower electrode 16B,
Electrons are emitted from the linear protrusion 14 that is the cathode.
For example, a voltage is applied to the high electrode 16A and the low electrode 16B at the same time, and a voltage not applied to the high electrode 16A and the low electrode 16B is applied to an anode (not shown) provided so as to face the protrusion 14. By applying a high positive voltage, most of the electrons emitted from the cathode can reach the anode.

Further, the high electrode 16A and the low electrode 16B
It is possible to control the amount and direction of electrons emitted from the cathode by applying a voltage to each of the electrodes independently.

Further, the high electrode 16A and the low electrode 16B
By using one of the electrodes, for example, the lower electrode 16B as an anode and the other electrode, for example, the higher electrode 16A as a control electrode, a minute vacuum triode element can be realized and applied to the control electrode. By modulating the applied voltage, the amount or direction of electrons emitted from the cathode to the anode can be modulated. This electron source is expected to operate at high speed because the distance in which electrons travel in a vacuum is extremely short, about submicron. Further, by providing a plurality of phosphors having different emission colors on the surface of the anode, it is possible to change the emission color by the voltage applied to the control electrode.

The first method of manufacturing the field emission electron source according to the first embodiment will be described below with reference to FIG.

First, the surface of the conductive substrate 10 made of silicon is thermally oxidized to form a silicon oxide film 17A on the surface portion of the conductive substrate 10 as shown in FIG. By performing photolithography on the silicon film 17A, as shown in FIG. 2B, an etching protection mask 17B having a linear boundary portion is formed.

Then, the region exposed on the mask 17B on the surface of the conductive substrate 10 is subjected to direction anisotropic dry etching from an oblique direction (upper right direction in FIG. 2), as shown in FIG. 2C. As described above, the lower surface 12, the high surface 13, the step portion 11 that intersects the high surface 13 at an acute angle, and the protrusions 14 are formed at the corners between the high surface 13 and the step portion 11.

Next, after removing the mask 17B, vapor deposition is performed in a direction substantially perpendicular to the upper surface 13 and the lower surface 12 to form a high insulating film 15A on the high surface 13. 16A of the lower electrode is formed on the lower surface 12 with the lower insulating film 15B interposed therebetween.
Form B. In this case, since the protrusion 14 functions as a vapor deposition mask, the vapor deposition film does not adhere to the lower surface 12 in the vicinity of the step portion 11, and the high electrode 16A and the low surface 12 on the high surface 13 are not deposited. The lower electrode 16B on the upper side of the upper surface is clearly separated from each other and faces each other via the protruding portion 14 which is the cathode. The distance between the protruding portion 14 and the high electrode 16A and the low electrode 16B is the same as that of the high insulating film 15A and the low insulating film 1.
5B, the thickness of the upper electrode 16A and the lower electrode 16B and the vapor deposition direction.

Next, the conductive substrate 10 is dipped in a hydrofluoric acid-based aqueous solution (anisotropic etching solution) to form the protrusions 1.
When the high-part insulating film 15A and the low-part insulating film 15B in the vicinity of 4 are set back, it is possible to form a cathode composed of the projecting parts 14 which are projected sharply.

In the field emission electron source according to the first embodiment, the upper electrode 16A, the lower electrode 16B and the conductive substrate 1 are used.
When a voltage is applied between the protruding portion 1 and the
Electrons are emitted from the cathode made of 4 in a direction perpendicular to the step portion 11.

After the dry etching from the oblique direction, the conductive substrate 10 is thermally oxidized to form a silicon oxide film on the surface of the step portion 11.
Immediately thereafter or by evaporation, the upper electrode 16A and the lower electrode 1
After forming 6B, if the silicon oxide film on the surface portion of the step portion 11 is removed with an aqueous solution of hydrofluoric acid, the protrusion 14 having a steeper cross-sectional shape is formed.

In the first embodiment, the silicon substrate is used as the conductive substrate 10. However, instead of this, a substrate made of metal or a glass substrate having a conductive material formed on its surface is used. You may use the insulating substrate.

In the first manufacturing method, the anisotropic anisotropic dry etching from the oblique direction is used for forming the step portion 11. However, when a crystalline substrate such as a semiconductor is used as the conductive substrate 10, Alternatively, the protrusion 14 having a steep cross-sectional shape may be formed by using crystal anisotropic etching.
In this case, since the cross-sectional shape of the protrusion 14 serving as the cathode is determined by the orientation of the crystal plane, it is possible to manufacture an electron source having highly reproducible characteristics. When a stepped portion is formed by a crystal anisotropic etching method using a conductive substrate made of a semiconductor, it is possible to form a protruding portion having a steep cross-sectional shape at all corners around the high electrode. This is possible, and it becomes easy to integrate a plurality of electron sources with high density.

The second manufacturing method of the field emission electron source according to the first embodiment of the present invention will be described below with reference to FIG.

First, the surface of the conductive substrate 30 made of silicon is thermally oxidized to form a silicon oxide film on the surface portion of the conductive substrate 30, and then the photolithography is performed on the silicon oxide film. As shown in FIG. 3 (a), there is a first boundary for etching protection for etching protection.
The mask 37 of is formed.

Next, the first on the surface of the conductive substrate 30
3B, dry etching is performed on the region exposed to the mask 37 from a direction perpendicular to the substrate surface or an oblique direction, so that as shown in FIG. A lower surface 32 and a higher surface 33 located on both sides of the step portion 31 are formed.

Next, after removing the first mask 37, as shown in FIG. 3C, the upper surface 3 is formed by thermal oxidation.
3, a thermal oxide film 35 is formed on the surface portions of the step portion 31 and the lower surface 32, and a metal film 36 is deposited on the thermal oxide film 35 by a sputtering method. After that, 1 step across the step 31
Higher part electrode 36A and lower part electrode 3 with an interval of μm or less
A second mask 38 for etching protection is formed on the metal film 36 by a resist so that 6B is arranged.

Next, the metal film 3 is formed using the second mask 38.
6 by performing dry etching on FIG.
As shown in (d), the metal film 36 and the thermal oxide film 35 near the step portion 31 are removed to form a high electrode 36A, a low electrode 36B, a high insulating film 35A, and a low insulating film 35B. To do.

Next, with the second mask 38 left, directional anisotropic dry etching is carried out from an oblique direction (upper right in FIG. 3), and as shown in FIG. After forming the protrusion 34 having an acute cross-sectional shape between the step 33 and the step 31, the second mask 38 is removed. Then, the conductive substrate 30 is dipped in a hydrofluoric acid-based aqueous solution to retreat the vicinity of the protruding portion 34 in the high insulating film 35A, and the protruding portion 34 is exposed.

Also in the field emission electron source obtained by the second manufacturing method, when a voltage is applied between the conductive substrate 30 and the upper electrode 36A and the lower electrode 36B, the protrusion as a cathode is produced due to the field effect. Electrons are emitted from the section 34.

After the direction anisotropic dry etching,
Thermal oxidation is performed on the conductive substrate 30 to form a silicon oxide film on the surface of the step portion 31. Immediately thereafter or after forming the high electrode 36A and the low electrode 36B by vapor deposition, When the silicon oxide film on the surface portion 22 of the step portion 31 is removed by an aqueous solution, the protrusion 34 having a steeper cross-sectional shape is formed.

Further, in the second manufacturing method, the silicon substrate is used as the conductive substrate 30, but instead of this, a substrate made of metal or a glass substrate having a conductive material formed on its surface, or the like. You may use the insulating substrate.

Further, in the second manufacturing method, direction anisotropic dry etching from an oblique direction is used for forming the step portion 31, but when a crystal substrate such as a semiconductor is used as the conductive substrate 30, Alternatively, the protrusion 34 having a steep cross-sectional shape may be formed by using crystal anisotropic etching. In this case, since the cross-sectional shape of the protrusion 34 serving as the cathode is determined by the orientation of the crystal plane, it is possible to manufacture an electron source having highly reproducible characteristics.

The third method of manufacturing the field emission electron source according to the first embodiment of the present invention will be described below with reference to FIG.

First, the surface of the conductive substrate 60 made of silicon is thermally oxidized to form a silicon oxide film 67A on the surface portion of the conductive substrate 60 as shown in FIG. By performing photolithography on the silicon film 67A, as shown in FIG. 4B, an etching protection mask 67B having a linear boundary portion is formed.

Next, as shown in FIG. 4C, directional anisotropic dry etching is performed from the oblique direction (upper right direction in FIG. 4) on the region exposed on the mask 67B on the surface of the conductive substrate 60. As described above, the lower surface 62, the higher surface 63, the step portion 61 that intersects the higher surface 63 at an acute angle, and the protrusion 64 is formed at the corner between the high surface 63 and the step portion 61.

Next, the thermal oxidation film 65 is formed on the step portion 61 and the bottom surface 62 by performing thermal oxidation while leaving the mask 67B. By doing so, the protrusion 64 having a steep cross-sectional shape is formed at the corner between the step 61 and the upper surface 63. A thin thermal oxide film may be formed on the upper surface 63 depending on the thickness of the mask 67B.

Next, a metal film is formed on the upper surface 63 by vapor deposition.
And the bottom surface 62, a high electrode 66A and a low electrode 66B are formed as shown in FIG. 4 (d).

Next, the conductive substrate 60 is dipped in a hydrofluoric acid-based aqueous solution (anisotropic etching solution) to form the mask 6
7B and the thermal oxide film 65 are removed, and as shown in FIG. 4E, the high part insulating film 65A receding from the high part electrode 66A and the low part insulating film 6 receding from the low part electrode 66B.
5B is formed. This makes it possible to expose the protrusion 64 having a steep cross-sectional shape. That is, the projecting portion 64 having an acute angle by the directional anisotropic dry etching is formed into a steep cross-sectional shape by the thermal oxidation process, and thus it is possible to operate at a low voltage.

In the third manufacturing method, the step portion 6
Although directional anisotropic dry etching was used to form No. 1, instead of this, it is also possible to use a silicon crystal plate as the conductive substrate and form the step portion by crystal anisotropic etching.

FIG. 5 shows the structure of a field emission electron source according to the second embodiment of the present invention, which is a case where a cathode having an acute cross section is formed by a crystal plane. .
As shown in FIG. 5, on a conductive substrate 20 made of a silicon substrate having a plane orientation of (100), a V-shaped surface having a (111) plane extending in the <011> direction at a predetermined interval. A plurality of step portions 21 having side surfaces are formed,
On both sides of each step 21, strip-shaped lower surface 22 and higher surface 23 are formed alternately. A high electrode 26A is formed on each high surface 23 via a high insulating film 25A, and a low electrode 26B is formed on each low surface 22 via a low insulating film 25B. There is. A protrusion 24 having a sharp cross-sectional shape and extending linearly is formed at a corner between the high plane 23 of the (100) plane and the step 21 of the (111) plane. A cathode is constructed.

In the field emission electron source according to the second embodiment, as in the first embodiment, when a positive electric field is applied to at least one of the high electrode 26A and the low electrode 26B with respect to the cathode, Electrons are radiated from the linear protrusion 24 that is.

Hereinafter, a method of manufacturing the field emission electron source according to the second embodiment will be described with reference to FIG.

First, a silicon oxide film is formed on the surface of a conductive substrate 20 made of a silicon substrate having a plane orientation of (100), and then photolithography is performed on the silicon oxide film to form the silicon oxide film shown in FIG. ),
A band-shaped etching protection mask 27 having a boundary along the <011> direction on the surface of the silicon substrate is formed.
Thereafter, by using the mask 27, the conductive substrate 20 is subjected to directional anisotropic dry etching from a direction substantially perpendicular to the substrate surface, so that the substrate is formed on the boundary portion of the mask 27 as shown in FIG. 6B. A step portion 21 perpendicular to the surface is formed, and a low surface 22 and a high surface 23 are formed on both sides of the step portion 21, respectively.

Next, when the crystal anisotropic etching is performed on the step portion 21 and the lower surface 22 using the mask 27, the (111) plane is exposed on the side surface as shown in FIG. 6C. A V-shaped recess is formed. In this case, mask 2
At the boundary portion of 7, the step portion 21 is etched inward, so that the protruding portion 24 having an acute sectional shape is formed.

Next, after removing the mask 27, vapor deposition is performed on the entire surface of the semiconductor substrate 20 to form the structure shown in FIG.
As shown in (d), the upper insulating film 2 is formed on the upper surface 23.
5A and the lower electrode 26B is formed on the lower surface 22 via the lower insulating film 25B.
To form. In this case, since the protrusion 24 acts as a mask for vapor deposition, the high electrode 26A and the low electrode 26B are formed in a state of being electrically separated from each other and sandwiching the protrusion 24, which is the cathode, therebetween.

Next, when the conductive substrate 20 is immersed in an aqueous solution of hydrofluoric acid, as shown in FIG. 6 (e), the vicinity of the protrusion 24 in the high-level insulating film 25A is removed and a sharp cross section is formed. The steep protrusion 24 that it has is exposed.

After the crystal anisotropic etching, the conductive substrate 20 is thermally oxidized to form a silicon oxide film on the surface of the step portion 21, and the silicon oxide film on the surface of the step portion 21 is removed by hydrofluoric acid. By removing it, the protrusion 24 having a steeper cross-sectional shape can be formed.

Further, as the conductive substrate 20, a gallium arsenide substrate can be used instead of the silicon substrate.

Instead of forming the high insulating film 25A, the low insulating film 25B, the high electrode 26A and the low electrode 26B by the vapor deposition method, the insulating method is performed by the CVD method or the sputtering method generally used in the semiconductor process. After forming the film and the conductive film, the insulating film and the conductive film are separated by a photo process to form the high insulating film 25A, the low insulating film 25B, the high electrode 26A, and the low electrode 26B. Good.

When a silicon substrate is used as the conductive substrate 20, it is possible to use a thermal oxidation method for the surface of the silicon substrate to form the insulating film.

FIG. 7 shows the structure of a field emission electron source according to the third embodiment of the present invention. As shown in FIG. 7, a conductive substrate 40 made of a silicon substrate having a plane orientation of (100). A plurality of step portions 41, which extend in the <011> direction at predetermined intervals and have V-shaped side surfaces of (111) planes, are formed on both sides of the step portion 41. A lower surface 42 and a higher surface 43 are formed.
A high electrode 46A is formed on the high surface 43 via a high insulating film 45A, and a low electrode 46B is formed on the low surface 42 via a low insulating film 45B. (1
A protrusion 44 having an acute-angled cross-section and extending linearly is formed at a corner between the high plane 43 of the (00) plane and the stepped portion 41 of the (111) plane. Is configured.

Also in the field emission type electron source according to the third embodiment, as in the first embodiment, when a positive electric field is applied to at least one of the high electrode 46A and the low electrode 46B with respect to the cathode, Electrons are radiated from the linear protruding portion 44 that is.

A first method of manufacturing a field emission electron source according to the third embodiment of the present invention will be described below with reference to FIG.

First, a silicon oxide film is formed on the surface of a conductive substrate 40 made of a silicon substrate having a plane orientation of (100), and then photolithography is performed on the silicon oxide film to form a silicon substrate surface. <01
A band-shaped first mask 47 for etching protection having a boundary along the 1> direction is formed. After that, the conductive substrate 40 is subjected to direction anisotropic dry etching from the direction substantially perpendicular to the substrate surface using the first mask 47, so that as shown in FIG. 47
A step portion 41 perpendicular to the surface of the substrate is formed at the boundary of the step portion 41, and a low portion surface 42 and a high portion surface 43 are formed on both sides of the step portion 41.

Next, after removing the first mask 47, as shown in FIG. 8B, the upper surface 4 is formed by thermal oxidation.
3, the thermal oxide film 4 on the surface of the step portion 41 and the lower surface 42.
5 is formed, and a metal film 46 is vapor-deposited on the thermal oxide film 45 by a sputtering method. After that, 1 μ across the step 41
Higher part electrode 46A and lower part electrode 46 at intervals of m or less
A second mask 49 for etching protection is formed of a resist on the metal film 46 so that B is arranged.

Next, the metal film 4 is formed using the second mask 49.
6 and the thermal oxide film 45 are dry-etched to remove the metal film 46 and the thermal oxide film 45 in the vicinity of the step portion 41, as shown in FIG. The lower electrode 46B, the higher insulating film 45A and the lower insulating film 45B are formed.

Next, the upper electrode 46A and the lower electrode 46B
When crystal anisotropic dry etching is performed using the mask as a mask, as shown in FIG. 8D, an acute angle is formed in the corner between the high plane 43 of the (100) plane and the step 41 of the (111) plane. A protrusion 44 having a linear cross section and extending linearly is formed, and the protrusion 44 constitutes a cathode. Then, the conductive substrate 40 is dipped in a hydrofluoric acid-based aqueous solution to retreat the vicinity of the protrusion 44 in the high-level insulating film 45A, and the protrusion 44 is exposed.

Also in the field emission type electron source obtained by the first manufacturing method, when a voltage is applied between the conductive substrate 40 and the upper electrode 46A and the lower electrode 46B, the field effect electron source causes the protrusion of the cathode. Electrons are emitted from the portion 44.

In the first manufacturing method, anisotropic dry etching is performed before performing crystal anisotropic dry etching using the upper electrode 46A and the lower electrode 46B as a mask to obtain a step on the conductive substrate 40. A recess may be formed near the portion 41.

The second manufacturing method of the field emission electron source according to the third embodiment of the present invention will be described below with reference to FIG.

First, after a silicon oxide film is formed on the surface of a conductive substrate 50 made of a silicon substrate having a plane orientation of (100), the silicon oxide film is subjected to photolithography to form a silicon substrate surface. <01
A band-shaped first mask 57 for etching protection having a boundary along the 1> direction is formed. After that, anisotropic dry etching is performed on the conductive substrate 50 from the direction substantially perpendicular to the substrate surface using the first mask 57, so that the first mask 57 is formed as shown in FIG. 9A. A step portion 51 perpendicular to the substrate surface is formed at the boundary of the step portion 51, and a low portion surface 52 and a high portion surface 53 are formed on both sides of the step portion 51.

Next, after removing the first mask 57, as shown in FIG. 9B, the upper surface 5 is formed by thermal oxidation.
3. The thermal oxide film 5 is formed on the surface of the step portion 51 and the lower surface 52.
5, a metal film 56 and a silicon oxide film 59 are deposited on the thermal oxide film 55 by a sputtering method. afterwards,
A second mask 58 for etching protection is formed by a resist on the silicon oxide film 59 so that the high electrode 56A and the low electrode 56B are arranged at intervals of 1 μm or less with the step portion 51 interposed therebetween. .

Next, anisotropic dry etching is performed on the silicon oxide film 59, the metal film 56, and the thermal oxide film 55 using the second mask 58, as shown in FIG. 9C. A silicon oxide film 59 near the step portion 51,
The metal film 56 and the thermal oxide film 55 are removed to form a strip-shaped silicon oxide film 59A, a high electrode 56A, a low electrode 56B, a high insulating film 55A, and a low insulating film 55B.

Next, the high electrode 56A and the low electrode 56B
By performing crystal anisotropic dry etching using the mask as a mask, a concave portion is formed in the vicinity of the step portion 51 in the conductive substrate 50 as shown in FIG.
High plane 53 of (100) plane and step 5 of (111) plane
A projecting portion 44 having a sharp cross-sectional shape and extending linearly is formed at a corner portion between 1 and 1.

Next, when the conductive substrate 50 is thermally oxidized, the peripheral portion of the concave portion near the step portion 51 of the conductive substrate 50 is thermally oxidized to form the thermal oxide film 50a.

Next, when the conductive substrate 50 is immersed in an aqueous solution of hydrofluoric acid, as shown in FIG. 9 (e), the vicinity of the protrusion 54 in the high-level insulating film 55A is removed and a sharp cross section is formed. The steep protruding portion 54 it has is exposed, and the protruding portion 54 constitutes a cathode.

In the second manufacturing method, a silicon crystal substrate is used as the conductive substrate 50, but a crystal substrate of gallium arsenide or the like can be used instead of this.

In each of the above embodiments, the protrusion serving as the cathode was linear, but instead of this, the boundary portion of the etching mask for forming the step portion was formed into a comb-like uneven shape or It may be processed into a sawtooth zigzag triangular shape. By doing so, electrons are emitted from the region that is the most steep in three dimensions, and it is possible to manufacture an electron source having a dot-shaped cathode.

FIG. 10 shows a field emission type electron source according to the fourth embodiment of the present invention, in which (a) is a plane structure and (b) is.
Shows a cross-sectional structure taken along line XX in (a).

As shown in FIG. 10, the plane orientation is (100)
On the conductive substrate 70 made of silicon, a plurality of lower surface 72 and a plurality of higher surface 73 are formed in a comb shape via a plurality of step portions 71 having a wine glass-like cross-sectional structure. The protrusion 74 having an acute cross section formed between each high surface 73 and each step 71 serves as a cathode. A high insulating film 75A is formed on each high surface 73.
76A of high-level electrodes are formed via the low-level insulating film 75B, and the low-level electrodes 76B are formed on the low-level surface 72 of each low-level insulating film 75B. High surface 73 and low surface 7
The boundary region 77 between the two is formed in the <011> direction orthogonal to each other. The projecting portion 74 has a steep cross-sectional shape, but in particular, the projected corner portion 74a has the three-dimensionally steepest structure, and electrons are emitted from the projected corner portion 74a.

The cross-sectional shape that crosses the high-part surface 73 and the low-part surface 72 is almost the same as the cross-sectional structure of the electron source according to the third example described with reference to FIG. 7, and according to the fourth example. The method of manufacturing the field emission electron source is almost the same as the method of manufacturing the electron source according to the third embodiment described with reference to FIG.

In the field emission electron source according to the fourth embodiment, electrons are emitted from the cathode by applying a positive voltage to the cathode to one or both of the upper electrode 76A and the lower electrode 76B. As well as being emitted, the amount and direction of emitted electrons can be controlled.

FIG. 11 shows a field emission electron source according to the fifth embodiment of the present invention, (a) shows a planar structure,
(B) has shown the cross-section of the XI-XI line in (a).

Although the field emission electron sources according to the first to fourth embodiments have a structure in which a voltage can be independently applied to each high electrode and each low electrode, the high electrode and the low electrode are previously prepared. It is possible to control the electrons radiated from the cathode and reaching the separately provided anode by using the upper electrode and the lower electrode as the electron extraction electrodes. Fifth
The embodiment has such a structure, and realizes an electron source with a larger current amount by arranging the electron sources in an array and increasing the length of the protrusion serving as the cathode. is there.

As shown in FIG. 11, the lower surface 82 and the higher surface 83 of a predetermined shape are arranged in an array, and the step portion 81 between the upper surface 83 and the lower surface 82 is sandwiched therebetween. A recess 87 having a predetermined shape is formed. Incidentally, FIG.
The dashed-dotted line in (a) shows the planar shape of the high surface 83 before the recess 87 is formed. In the field emission electron source according to the fifth embodiment, the quadrangular upper surface 83 having each side arranged in the <011> direction is arranged so as to be surrounded by the lower surface 82. Recess 87 at
A protruding portion 84 (shown by a thick line in FIG. 11A) which is a corner between the high surface 83 and the stepped portion 81 is formed, and the protruding portion 84 constitutes a cathode. To be done. As shown in FIG. 11B, a high electrode 86A is formed on the high surface 83 via a high insulating layer 85A.
And the lower insulating film 8 is formed on the lower surface 82.
The lower electrode 86B is formed via 5B. Then, as described above, the high electrode 86A and the low electrode 86B
And are electrically connected to each other, and a voltage is applied at the same time.

The method of manufacturing the field emission type electron source according to the fifth embodiment is almost the same as that of the electron source of the third embodiment, and instead of the strip-shaped first mask 47 for etching in FIG. An etching mask may be used.

In FIG. 11, the concave portions 87 are formed on the opposing long sides of the high surface 83, respectively. Instead of this, as shown in FIG. 12, all four sides of the high surface 83 are formed. You may form the recessed part 87 in it. By doing so, a larger amount of current can be obtained.

Further, in the fifth embodiment, the upper surface 8
3 shows the case where the upper electrode 86A and the lower electrode 86B of one layer are formed on the lower surface 82.
6A and the lower electrode 86B do not necessarily have to be a single layer, and even if the upper electrode and the lower electrode of the second layer are formed on the upper electrode 86A and the lower electrode 86B via an insulating film. Good. In this way, the amount of electrons extracted by the first layer electrode can be controlled by the second layer electrode. In this case, the upper electrode and the lower electrode of the first layer are separated into a plurality of electrodes arranged in the X direction,
By separating the upper electrode and the lower electrode of the layer into a plurality of electrodes arranged in the Y direction orthogonal to the X direction, the emitted electron source can be two-dimensionally selected. This enables application to image display devices and the like.

[0142]

According to the field emission type electron source of the first aspect of the present invention, since the cathode can be formed by etching the substrate, the cathode having the same shape in the central portion and the peripheral portion of the substrate can be realized with good reproducibility. Moreover, since the distance between the cathode and the high electrode can be determined by the thickness of the insulating layer, the distance between the cathode and the high electrode can be controlled in the submicron order. Further, since the cathode can be formed without using the lift-off process, the cathode forming step can be incorporated in the semiconductor process, and the electron source and the LSI can be integrated.

The upper electrode and the lower electrode are electrically separated,
One of the upper electrode and the lower electrode functions as an extraction electrode and the other electrode functions as an anode, and the voltage applied to one electrode is changed to easily realize a triode element. it can. Further, when the anode is separately arranged so as to face the cathode, the amount or direction of electrons emitted from the cathode and directed to the anode can be controlled by changing the voltage applied to one or the other electrode, so that it is a quadrupole tube. The element or the electron beam polarization element can be easily realized.

On the other hand, the upper electrode and the lower electrode are electrically connected, the anode is separately arranged so as to face the cathode, and a voltage is simultaneously applied to one electrode and the other electrode, so that the cathode is radiated. Since most of the electrons generated can reach the anode, it is possible to realize an electron source in which a large current flows from the anode to the cathode.

According to the field emission type electron source of the second aspect of the present invention, both the upper electrode and the lower electrode can function as extraction electrodes, so that an electron source in which a large current flows from the anode to the cathode can be realized. .

According to the field emission electron source of the third aspect of the present invention, one of the upper electrode and the lower electrode can function as an extraction electrode and the other electrode can function as an anode. .

According to the field emission type electron source of the fourth aspect of the present invention, one of the upper electrode and the lower electrode functions as the extraction electrode and the other electrode functions as the control electrode, and the cathode and By separately disposing the anodes so as to face each other, a quadrupole tube element or an electron beam polarization element can be easily realized.

According to the field emission electron source of the fifth aspect of the present invention, one electrode of the upper electrode and the lower electrode is made to function as the extraction electrode and the other electrode is made to function as the anode. The tube element can be easily realized.

According to the field emission electron source of the sixth or seventh aspect of the present invention, the cathode having an acute sectional shape is formed by crystal anisotropic etching, so that a cathode having a uniform sectional shape can be realized with good reproducibility. it can.

According to the field emission type electron source of the eighth aspect of the present invention, it is possible to reproducibly realize a linear cathode having an acute sectional shape and capable of emitting electrons at a low current.

According to the field emission type electron source of the ninth aspect of the present invention, it is possible to reproducibly realize a dot-shaped cathode having an acute sectional shape and capable of emitting electrons with an extremely low current.

According to the field emission type electron source of the tenth aspect of the present invention, it is possible to efficiently arrange a single electron source including a combination of the cathode and the extraction electrode in a linear or matrix form.

Further, similarly to the invention of claim 1, the high electrode and the low electrode are electrically separated, and one of the high electrode and the low electrode is made to function as a lead electrode and the other electrode is The triode element can be easily realized by causing the electrode of 1 to function as an anode and changing the voltage applied to one of the electrodes. Further, when the anode is separately arranged so as to face the cathode, the amount or direction of the electrons emitted from the cathode and directed to the anode can be controlled by changing the voltage applied to one or the other electrode. The element or the electron beam polarization element can be easily realized. On the other hand, by electrically connecting the high electrode and the low electrode, separately disposing the anode so as to face the cathode, and applying a voltage to one electrode and the other electrode simultaneously, electrons emitted from the cathode Since most of them can reach the anode, it is possible to realize an electron source in which a large current flows from the anode to the cathode.

According to the field emission type electron source of the eleventh aspect of the present invention, both the upper electrode and the lower electrode can function as the electron extraction electrodes.

According to the field emission type electron source of the twelfth aspect of the present invention, one of the upper electrode and the lower electrode can function as an extraction electrode and the other electrode can function as an anode. By separately disposing the anode so as to face the cathode, the amount or direction of electrons emitted from the cathode and directed to the anode can be controlled by changing the voltage applied to one electrode and the other electrode.

According to the method of manufacturing a field emission type electron source of the thirteenth aspect of the present invention, since the cathode can be formed without using the lift-off process, it is possible to incorporate the cathode forming step into the semiconductor process. Since it can be integrated with the LSI, and the distance between the cathode and the high electrode can be determined by the thickness of the insulating layer, the distance between the cathode and the high electrode can be controlled in the submicron order.

According to the method of manufacturing a field emission type electron source of the fourteenth aspect of the present invention, the shape of the cathode can be regulated by the etching conditions. Therefore, the cathode having the same shape in the central portion and the peripheral portion of the substrate can be reproducibly reproduced. In addition, the high electrode and the low electrode separated by the step can be formed in a self-aligned manner.

According to the field emission type electron source manufacturing method of the fifteenth aspect of the present invention, since the shape of the cathode can be regulated by the etching conditions, the cathode having the same shape in the central portion and the peripheral portion of the substrate can be reproduced with good reproducibility. This can be realized, and the distance between the upper electrode and the lower electrode can be controlled by the etching mask.

According to the method of manufacturing an electro-emission electron source according to the sixteenth aspect of the present invention, a cathode having an acute cross section can be formed by directional anisotropic etching, so that a cathode having a uniform cross section can be easily realized. be able to.

According to the method of manufacturing a field emission type electron source of the seventeenth aspect of the present invention, a cathode having an acute cross section can be formed by crystal anisotropic etching, so that a cathode having a uniform cross section can be realized with good reproducibility. can do.

According to the method of manufacturing a field emission electron source according to the eighteenth aspect of the present invention, since the step portion is formed by using both the direction anisotropic etching and the crystal anisotropic etching on the crystalline substrate, the step is formed uniformly. It is possible to easily realize a cathode having a different cross-sectional shape with good reproducibility. According to the method of manufacturing a field emission type electron source of the invention of claim 19, since the step of removing the silicon oxide film formed on the surface portion of the step portion is included, a cathode having a steep sectional shape can be easily realized. be able to.

According to the manufacturing method of the field emission electron source of the 20th aspect of the present invention, the shape of the cathode can be determined by the etching conditions. Therefore, the cathode having the same shape is reproduced in the center and the peripheral portion of the substrate. Since it can be realized with good performance and the cathode can be formed without using the lift-off process, it becomes possible to incorporate the cathode forming step in the semiconductor process, so that the electron source and the LSI can be integrated with each other. Since the distance to the high electrode can be determined by the thickness of the insulating layer, which can be easily controlled, the distance between the cathode and the high electrode can be controlled in the submicron order. Further, since the silicon oxide film formed on the surface portion of the step portion made of silicon is removed, a cathode having a steep cross-sectional shape can be easily realized.

[Brief description of drawings]

FIG. 1 is a perspective view of a field emission electron source according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view showing each step of the first manufacturing method of the field emission electron source according to the first embodiment.

FIG. 3 is a cross-sectional view showing each step of the second manufacturing method of the field emission electron source according to the first embodiment.

FIG. 4 is a cross-sectional view showing each step of the third manufacturing method of the field emission electron source according to the first embodiment.

FIG. 5 is a perspective view of a field emission electron source according to a second embodiment of the present invention.

FIG. 6 is a cross-sectional view showing each step of the method for manufacturing the field emission electron source according to the second embodiment.

FIG. 7 is a perspective view of a field emission electron source according to a third embodiment of the present invention.

FIG. 8 is a cross-sectional view showing each step of the first manufacturing method of the field emission electron source according to the third embodiment.

FIG. 9 is a cross-sectional view showing each step of the second manufacturing method of the field emission electron source according to the third embodiment.

FIG. 10 shows a field emission electron source according to a fourth embodiment of the present invention, (a) is a plan view and (b) is (a).
6 is a cross-sectional view taken along line XX in FIG.

FIG. 11 shows a field emission electron source according to a fifth embodiment of the present invention, (a) is a plan view and (b) is (a).
FIG. 6 is a sectional view taken along line XI-XI in FIG.

FIG. 12 is a plan view showing a modification of the field emission electron source according to the fifth embodiment.

FIG. 13 is a cross-sectional view showing each step of a method for manufacturing a first conventional field emission electron source.

FIG. 14 is a cross-sectional view showing each step of a second conventional method of manufacturing a field emission electron source.

FIG. 15 is a perspective view of a third conventional field emission electron source.

FIG. 16 is a cross-sectional view showing each step of a method for manufacturing a third conventional field emission electron source.

FIG. 17 is a cross-sectional view showing each step of a method for manufacturing a fourth conventional field emission electron source.

[Explanation of symbols]

 10 Conductive Substrate 11 Stepped Part 12 Lower Part Surface 13 High Part Surface 14 Protruding Part (Cathode) 15A High Part Insulating Film 16A High Part Electrode 15B Lower Part Insulating Film 16A Lower Part Electrode 17A Silicon Oxide Film 17B Mask 20 Conductive Substrate 21 Step 22 Low surface 23 High surface 24 Projection (cathode) 25A High insulating film 25B Low insulating film 26A High electrode 26B Low electrode 27 Mask 30 Conductive substrate 31 Step 32 Low surface 33 High Surface 34 Projection (cathode) 35 Oxide film 35A High insulating film 35B Low insulating film 36 Metal film 36A High electrode 36B Low electrode 37 First mask 38 Second mask 40 Conductive film 41 Step 42 Low Part surface 43 High surface 44 Protrusion (cathode) 45A High insulating film 45B Low insulating film 46A High electrode 46B Low electrode 47 First mask KU 49 Second mask 50 Conductive substrate 50a Thermal oxide film 51 Step portion 52 Lower surface 53 Higher surface 54 Projection (cathode) 55A Higher insulating film 55B Lower insulating film 56A Higher electrode 56B Lower electrode 57 First mask 58 Second mask 59 Silicon oxide film 59A Band-shaped silicon oxide film 60 Conductive substrate 61 Stepped portion 62 Lower surface 63 Higher surface 64 Projection (cathode) 65 Thermal oxide film 65A Higher insulating film 65B Low part insulating film 66A High part electrode 66B Low part electrode 67A Silicon oxide film 67B Mask 70 Conductive substrate 71 Step part 72 Low part surface 73 High part surface 74 Protruding part (cathode) 74a Outer corner part 75A High part insulating film 75B Low Part insulating film 76A High part electrode 76B Low part electrode 77 Border region 80 Conductive substrate 81 Step part 82 Low part surface 83 High part surface 84 Projection Output part (cathode) 85A High part insulating film 85B Low part insulating film 86A High part electrode 86B Low part electrode 87 Recess

Claims (20)

[Claims] 1. A low surface and a conductive high surface formed on a substrate via a step portion, a cathode formed at a corner between the high surface and the step portion, and the high portion. A high electrode that is formed on the surface through an insulating layer, faces the cathode and is electrically insulated from the cathode, and a high electrode that is formed on the low surface and faces the cathode. A lower electrode electrically insulated from the cathode, and a voltage is applied between the cathode and at least one of the upper electrode and the lower electrode, and electrons are emitted from the cathode. And a field emission electron source. 2. The high electrode and the low electrode are electrically connected to each other, and a positive voltage is applied to the high electrode and the low electrode with respect to the cathode. The field emission electron source according to claim 1. 3. The high electrode and the low electrode are electrically separated from each other, and a voltage is applied to the high electrode and the low electrode independently of each other. The field emission electron source according to claim 1. 4. The amount or direction of electrons emitted from the cathode toward the anode is controlled by controlling the voltages applied to the upper electrode and the lower electrode, respectively. The field emission electron source described. 5. A positive constant voltage is applied to one electrode of the high electrode and the low electrode while the positive electrode is applied to the other electrode of the high electrode and the low electrode. 4. The field emission electron source according to claim 3, wherein the amount of electrons emitted from the cathode and directed to the one electrode is changed by changing the applied voltage. 6. The substrate is a crystalline substrate, and the cathode is formed at an acute angle at a corner between the high surface and the step by crystal anisotropic etching of the substrate. The field emission electron source according to claim 1. 7. The field emission electron source according to claim 6, wherein the substrate is a crystalline substrate, and the upper surface is formed on the (100) plane of the substrate. 8. The cathode is formed into a linear shape having an acute cross section by exposing a (111) plane extending in the <011> direction to the step portion by crystal anisotropic etching of the substrate. The field emission electron source according to claim 7, wherein 9. The dot-shaped cathode having an acute cross-sectional shape by (111) planes extending in the <011> direction and being orthogonal to each other are exposed at the step portion by crystal anisotropic etching of the substrate. The field emission type electron source according to claim 7, wherein 10. A plurality of lower surface portions and a plurality of conductive upper surface portions, which are respectively formed on a substrate through step portions and are arranged in a straight line or a matrix shape, a plurality of high surface portions, and A plurality of cathodes formed at corners of a plurality of step portions, and an insulating layer formed on the surfaces of the plurality of high portions, facing the cathode and electrically insulated from the cathode. A plurality of upper electrodes, a plurality of lower electrodes formed on the plurality of lower surfaces, facing the cathode, and electrically insulated from the cathode; And a field emission electron source which emits electrons from the plurality of cathodes when a voltage is applied between the plurality of lower electrodes and a plurality of lower electrodes and the plurality of cathodes. 11. The plurality of upper electrodes and the plurality of lower electrodes are electrically connected to each other, and a positive voltage with respect to the cathode is applied to the plurality of upper electrodes and the plurality of lower electrodes. 11. The applied voltage is applied.
The field emission electron source according to. 12. The plurality of high electrodes and the plurality of low electrodes are electrically separated from each other, and a voltage is independently applied to the plurality of high electrodes and the plurality of low electrodes. It is applied, The claim 1 characterized by the above-mentioned.
The field emission electron source according to 0. 13. A cathode forming step of forming a cathode at a corner between the high surface and the step portion by forming a high surface and a low surface on a conductive substrate through a step portion. An electrode forming step of forming a high electrode on the high surface through an insulating layer and forming a low electrode on the low surface through an insulating layer. Method for manufacturing field emission electron source. 14. The cathode forming step comprises: a first step of forming an etching mask of a predetermined shape on the conductive substrate; and a step of etching the conductive substrate using the etching mask. A second step of forming a stepped portion, wherein the electrode forming step sequentially forms an insulating material and a conductive material on the high surface and the low surface from a direction perpendicular to the substrate surface. 14. The method of manufacturing a field emission electron source according to claim 13, further comprising the step of forming the upper electrode and the lower electrode by vapor deposition. 15. The cathode forming step comprises a first step of forming a first etching mask having a predetermined shape on a conductive substrate, and etching of the conductive substrate using the first etching mask. And a second step of forming the step portion by performing the step of forming a step, the electrode forming step includes a first step of forming a conductive film on the conductive substrate via an insulating layer, and Second forming a second etching mask of a predetermined shape on the conductive film
And a third step of forming the high electrode and the low electrode by etching the conductive film using the second etching mask. The method of manufacturing a field emission electron source according to claim 13. 16. The second step in the step of forming a cathode comprises performing directional anisotropic etching from a direction inclined with respect to a direction perpendicular to a substrate surface as the etching to obtain the corner having an acute cross-sectional shape. 16. The method for manufacturing a field emission electron source according to claim 14, further comprising a step of forming a portion. 17. The conductive substrate is a crystalline substrate, and in the second step of the cathode forming step, crystal anisotropic etching is performed as the etching to form the corner portion having an acute sectional shape. 16. The method for manufacturing a field emission electron source according to claim 14, further comprising the step of forming. 18. The conductive substrate is a crystalline substrate, and the second step in the cathode formation step is, as the etching, directional anisotropic etching from a direction inclined with respect to a direction perpendicular to the substrate surface. The step of forming the corner portion having a sharp cross-sectional shape by performing crystal anisotropic etching after the step of performing the above step.
16. The method for manufacturing a field emission electron source according to 4 or 15. 19. The conductive substrate is a substrate made of silicon, and in the cathode forming step, after the second step, heat treatment is performed on the conductive substrate to form a surface portion of the step portion. 16. The method according to claim 14, further comprising a third step of forming the silicon oxide film and then removing the silicon oxide film to form the corner portion in a steep cross-sectional shape. Method for manufacturing field emission electron source. 20. A first step of forming an etching mask of a predetermined shape made of a silicon oxide film on a conductive substrate made of silicon, and etching the conductive substrate using the etching mask. A second step of forming a cathode at a corner between the high surface and the step portion by forming a high surface and a low surface on the conductive substrate via a step portion; Heat-treating the flexible substrate to form an insulating layer on each of the upper surface and the lower surface and a silicon oxide film on the surface of the step portion; A conductive material on the flexible substrate from a direction perpendicular to the substrate surface to form a high electrode on the high surface via the insulating layer and on the low surface. The insulating layer Forming a lower electrode through the fourth
And a fifth step of removing the silicon oxide film formed on the surface of the step portion to make the corner portion have a steep cross-sectional shape. Method of manufacturing electron source.