JP3112456B1 - Field emission type electron source, method of manufacturing the same, and display - Google Patents

Abstract

Kind Code: A1 Provided is a field emission type electron source that can be easily increased in area and reduced in cost, and a method for manufacturing the same. A strong electric field drift layer is formed on the surface side of an n-type silicon substrate as a conductive substrate, and a conductive thin film made of a gold thin film is formed on the strong electric field drift layer.
An ohmic electrode 2 is formed on the back surface of the n-type silicon substrate 1. Electrons injected into the strong electric field drift layer 6 from the n-type silicon substrate 1 drift toward the surface in the strong electric field drift layer 6 and are emitted through the conductive thin film 7. The strong electric field drift layer 6 is formed by making the surface side of the polycrystalline silicon 3 formed on the n-type silicon substrate 1 porous by anodic oxidation treatment, and then oxidizing with dilute nitric acid.

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 source which emits an electron beam by field emission using a semiconductor material, a method of manufacturing the same, and a display.

[0002]

2. Description of the Related Art Conventionally, as a field emission type electron source, there is a so-called Spindt electrode disclosed in, for example, US Pat. No. 3,665,241. This Spindt-type electrode has a substrate on which a number of minute triangular pyramid-shaped emitter chips are arranged, a gate layer having a radiation hole for exposing the tip of the emitter chip, and being arranged insulated from the emitter chip. And applying a high voltage with the emitter tip as a negative electrode to the gate layer in a vacuum to emit an electron beam from the tip of the emitter tip through a radiation hole.

However, the Spindt-type electrode has a complicated manufacturing process, and it is difficult to accurately form a large number of triangular pyramid-shaped emitter chips. For example, the Spindt-type electrode has a large area when applied to a flat light emitting device or a display. There was a problem that was difficult. In the Spindt-type electrode, the electric field is concentrated at the tip of the emitter tip, so if the degree of vacuum around the tip of the emitter tip is low and residual gas is present, the emitted gas turns the residual gas into positive ions. Since the ions are ionized and the positive ions collide with the tip of the emitter tip, the tip of the emitter tip is damaged (for example, damage due to ion bombardment), and the current density and efficiency of emitted electrons become unstable. There is a problem that the life of the chip is shortened. Therefore, the Spindt-type electrode needs to be used in a high vacuum (about 10 ⁻⁵ Pa to about 10 ⁻⁶ Pa) in order to prevent such a problem from occurring, which increases the cost and complicates handling. There was a problem.

In order to improve this kind of problem, MIM
(Metal Insulator Metal) method and MOS (Metal Oxid
e Semiconductor) type field emission electron sources have been proposed. The former is a flat field emission type electron source having a metal-insulating film-metal structure, and the latter is a metal-oxide film-semiconductor stacked structure. However, in order to increase the emission efficiency of electrons in this type of field emission type electron source (to emit many electrons), it is necessary to reduce the thickness of the insulating film and the oxide film. If the thickness of the insulating film or the oxide film is too thin, dielectric breakdown may occur when a voltage is applied between the upper and lower electrodes of the laminated structure. Since the thickness of the insulating film or the oxide film is limited, the electron emission efficiency (drawing efficiency) cannot be increased.

In recent years, Japanese Patent Application Laid-Open No. 8-250766
As disclosed in Japanese Unexamined Patent Publication, a porous semiconductor layer (porous silicon layer) is formed by using a single-crystal semiconductor substrate such as a silicon substrate and anodizing one surface of the semiconductor substrate. A field emission electron source (semiconductor cold electron emission device) has been proposed in which a metal thin film is formed on a porous semiconductor layer, and a voltage is applied between the semiconductor substrate and the metal thin film to emit electrons. I have.

[0006] However, the above-mentioned Japanese Patent Application Laid-Open No. Hei 8-2507 has been disclosed.
In the field emission electron source described in Japanese Patent Publication No. 66, since the substrate is limited to a semiconductor substrate, there is a problem that it is difficult to increase the area and reduce the cost. In addition, Japanese Patent Application Laid-Open No. 8-25076
In the field emission type electron source described in Japanese Patent Application Publication No. 6 (1995) -76, a so-called popping phenomenon easily occurs during electron emission, and the amount of emitted electrons tends to be uneven. There is.

Therefore, the present inventors have filed Japanese Patent Application No. Hei.
No. 72340, Japanese Patent Application No. 10-272342, Japanese Patent Application No. 1
No. 0-271876, a conductive substrate (eg, a metal thin film) is oxidized by a rapid thermal oxidation (RTO) technique in which a porous polycrystalline silicon layer as a porous layer is oxidized by a rapid heating method. )
We proposed a field emission type electron source with a strong electric field drift layer in which electrons injected from a conductive substrate are interposed between a thin film and a conductive thin film.

Here, the porous polycrystalline silicon layer is formed by making the polycrystalline silicon layer on the conductive substrate porous by anodizing. As an electrolytic solution used for the anodizing treatment, a solution obtained by mixing a hydrogen fluoride aqueous solution and ethanol at a ratio of about 1: 1 is used. Also,
As a condition for oxidizing the porous polycrystalline silicon layer by the rapid heating method, a lamp annealing device is used,
It has been proposed to set the oxidation temperature in dry oxygen within a temperature range of 800 ° C. to 900 ° C. and the oxidation time within a range of 30 minutes to 120 minutes (Japanese Patent Application No. 10-271 mentioned above).
876). In addition, the conductive thin film requires that electrons that reach the surface of the strong electric field drift layer (the reached electrons are considered to be hot electrons) are tunneled without being scattered in the conductive thin film and released into a vacuum. Therefore, it is formed of a gold thin film having a thickness of about 10 nm.
In this field emission type electron source, the electron emission characteristics have a small dependence on the degree of vacuum, and can stably emit electrons without generating a popping phenomenon during electron emission. In addition, a single crystal silicon substrate or the like is used as a conductive substrate. In addition to the semiconductor substrate described above, a substrate in which a conductive film (for example, an ITO film) is formed on a glass substrate or the like can be used. Therefore, a porous semiconductor layer in which a semiconductor substrate is made porous as in the related art is used. As compared with the case and the Spindt-type electrode, the area of the electron source can be increased and the cost can be reduced. When a display device is configured using such a field emission electron source, it is necessary to pattern a metal thin film into a predetermined shape.

[0009]

However, the above-mentioned Japanese Patent Application Nos. Hei 10-272340 and Hei 10-27234 are disclosed.
No. 2, Japanese Patent Application No. 10-271876, the field emission type electron source cannot raise the oxidation temperature of rapid thermal oxidation above the heat resistant temperature of the conductive substrate. , ITO film) is limited, and there is a problem that a large-diameter (large-area) substrate is restricted.

In addition, the porous semiconductor layer (porous polycrystalline silicon layer or porous silicon layer) formed by the anodic oxidation treatment as described above is treated with an aqueous solution of hydrogen fluoride and ethanol as an electrolytic solution in the anodic oxidation treatment. Is used, the silicon atoms are terminated by hydrogen atoms. For this reason, the above-mentioned Japanese Patent Application No. 10-2723 is disclosed.
No. 40, Japanese Patent Application No. 10-272342, Japanese Patent Application No. 10-2
When an oxide film is grown by performing rapid thermal oxidation on a porous semiconductor layer formed by anodic oxidation treatment as disclosed in Japanese Patent No. 71876, hydrogen atoms may remain in the oxide film or Si-OH bonds may occur. As a result, there is a problem that a dense oxide film having a structure of SiO ₂ is hardly formed and the withstand voltage is lowered. In addition, the content of hydrogen in the strong electric field drift layer becomes relatively large, and the distribution of hydrogen in the strong electric field drift layer changes with time (for example, hydrogen atoms desorb from the surface of the strong electric field drift layer). In addition, there is a possibility that the stability of electron emission efficiency over time is deteriorated.

Further, the above-mentioned Japanese Patent Application No. 10-272340.
No., Japanese Patent Application No. 10-272342, Japanese Patent Application No. 10-271
In the field emission type electron source proposed in US Pat.
Although the cost can be reduced and the electrons can be stably emitted with high efficiency as compared with the field emission type electron source disclosed in Japanese Patent No. 250766, the electron emission efficiency can be further increased. Is desired.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and a first object is to provide a field emission type electron source which can be easily made large in size and low in cost. To provide a method for manufacturing a field emission electron source having a small change with time in electron emission efficiency and high withstand voltage.
A third object is to provide a method of manufacturing a low-cost field emission electron source capable of stably and efficiently emitting electrons.

[0013]

According to a first aspect of the present invention, there is provided a conductive substrate, a strong electric field drift layer formed on one surface side of the conductive substrate, and a conductive layer formed on the strong electric field drift layer. A field emission type electron in which electrons injected from the conductive substrate are drifted through the strong electric field drift layer and emitted through the conductive thin film by applying a voltage with the conductive thin film as a positive electrode with respect to the conductive substrate. A strong electric field drift layer, wherein the strong electric field drift layer is formed by a process including an oxidation step of electrochemically oxidizing the porous semiconductor layer in an electrolyte solution. Since the strong electric field drift layer is formed by oxidation using a process including an oxidation step of electrochemical oxidation in an electrolyte solution, the porous semiconductor layer is oxidized only by the rapid heating method to form the strong electric field drift layer. Process temperature becomes a low temperature, the material limitations of the conductive substrate is reduced as compared with the case where,
Large area and low cost can be easily achieved. The invention according to claim 2 includes a conductive substrate, a strong electric field drift layer formed on one surface side of the conductive substrate, and a conductive thin film formed on the strong electric field drift layer. A field emission type electron source in which electrons injected from the conductive substrate are drifted through the strong electric field drift layer and emitted through the conductive thin film by applying a voltage as a positive electrode to the conductive substrate,
The strong electric field drift layer is a porous semiconductor layer
Is formed by a process comprising oxidation step of relatively oxidized at low temperature crystal silicon layer, even without small, the polycrystalline silicon of the pillar formed on the first surface side of the conductive substrate, nano interposed between the polycrystalline silicon A microcrystalline silicon layer having a structure, and a silicon oxide film formed on the surface of the microcrystalline silicon layer and having a thickness smaller than the crystal grain size of the microcrystalline silicon layer. semiconductor
The porous polycrystalline silicon layer, which is a layer, is oxidized by a process including an oxidation step of oxidizing the layer at a relatively low temperature to form a strong electric field drift layer. The process temperature is lower than in the case of forming an electric field drift layer, the restriction on the material of the conductive substrate is reduced, the area and cost can be easily reduced, and the strong electric field drift layer has at least A columnar polycrystalline silicon formed on the one surface side of the conductive substrate, a microcrystalline silicon layer having a nanostructure interposed between the polycrystalline silicon, and the microcrystalline silicon formed on the surface of the microcrystalline silicon layer. Since it is composed of a silicon oxide film having a thickness smaller than the crystal grain size of the layer, the dependence of the electron emission characteristics on the degree of vacuum is small and the electron emission is stable without popping phenomenon during electron emission. It can be released.

According to a third aspect of the present invention, in the second aspect , the oxidizing step is a step of oxidizing the porous semiconductor layer in a liquid.

According to a fourth aspect of the present invention, in the third aspect of the present invention, the liquid comprises an acid.

According to a fifth aspect of the present invention, in the fourth aspect , the acid is selected from the group consisting of HNO ₃ , H ₂ SO ₄ and aqua regia.

The invention according to claim 6 is the invention according to claims 1 to
The invention according to claim 5 , wherein the porous semiconductor layer is made of porous single-crystal silicon.

The invention according to claim 7 is the invention according to claims 1 to
In the invention of the fifth aspect , since the porous semiconductor layer is made of porous polycrystalline silicon, the electron emission characteristics have a small dependence on the degree of vacuum, and a popping phenomenon does not occur at the time of electron emission, and electrons are emitted stably and efficiently. can do.

According to the present invention, a strong electric field drift layer composed of a conductive substrate, an oxidized porous semiconductor layer formed on one surface side of the conductive substrate, and a strong electric field drift layer formed on the strong electric field drift layer An electric field emission, wherein electrons injected from the conductive substrate are drifted through the strong electric field drift layer and emitted through the conductive thin film by applying a voltage with the conductive thin film as a positive electrode with respect to the conductive substrate. A method of manufacturing a porous electron source, comprising: oxidizing the porous semiconductor layer at a relatively low temperature when oxidizing the porous semiconductor layer, wherein the main oxidation processing step comprises: The process is characterized by electrochemically oxidizing the layer in an electrolyte solution.The process temperature can be reduced compared to the case where a porous semiconductor layer is oxidized by a rapid heating method to form a strong electric field drift layer. , The material limitations of the conductive substrate is reduced, it is possible to provide a field emission electron source that can have a large area and low cost. The invention of claim 9 provides a conductive substrate, a strong electric field drift layer formed of an oxidized porous semiconductor layer formed on one surface side of the conductive substrate, and a conductive thin film formed on the strong electric field drift layer. Wherein the oxidized porous semiconductor layer , which is a strong electric field drift layer, comprises at least a columnar polycrystalline silicon formed on the one surface side of the conductive substrate and a nanostructure interposed between the polycrystalline silicons A microcrystalline silicon layer and a silicon oxide film formed on the surface of the microcrystalline silicon layer and having a thickness smaller than the crystal grain size of the microcrystalline silicon layer. A method of manufacturing a field emission type electron source in which electrons injected from a conductive substrate are drifted through a strong electric field drift layer and emitted through a conductive thin film. It is characterized in that it comprises a main oxidation treatment step of oxidizing the porous semiconductor layer at a relatively low temperature, so that the porous semiconductor layer is oxidized by a rapid heating method to form a strong electric field drift layer. The temperature can be reduced, the restriction on the material of the conductive substrate is reduced, the area can be increased and the cost can be reduced. In addition, the dependence of the electron emission characteristics on the degree of vacuum is small, and a popping phenomenon occurs during electron emission. And a field emission type electron source capable of stably emitting electrons without generation of electrons. The invention of claim 10 is
In a preferred embodiment of the present invention, the electrolyte solution is made of an acid.

According to an eleventh aspect of the present invention, in the ninth aspect of the present invention, the main oxidation step oxidizes the porous semiconductor layer in a liquid. In the case of forming by this, the porous semiconductor layer can be oxidized by wet treatment subsequent to the anodic oxidation treatment, so that the process can be simplified as compared with the case of oxidizing by the rapid heating method after the anodic oxidation treatment. .

A twelfth aspect of the present invention is a preferred embodiment, wherein the liquid is an acid in the eleventh aspect of the present invention.

[0022]

[0023]

According to a thirteenth aspect of the present invention, in the invention of the eighth to twelfth aspects, at least one of before and after the main oxidation treatment step, an auxiliary for oxidizing the porous semiconductor layer by a thermal oxidation method. Since the oxidation process is provided, the electron emission efficiency can be increased.

According to a fourteenth aspect of the present invention, in the invention of the eighth to twelfth aspects, a pre-oxidation step of oxidizing the porous semiconductor layer with an oxidizing solution is provided before the main oxidation step. Thus, the electron emission efficiency can be increased . According to a fifteenth aspect of the present invention, a conductive substrate and a conductive group are provided.
From the oxidized porous semiconductor layer formed on one side of the plate
Strong electric field drift layer and formed on the strong electric field drift layer
A conductive thin film on a conductive substrate.
By applying a voltage as a positive electrode to the conductive substrate
Electrons injected from the substrate drift in the strong electric field drift layer and
Method of manufacturing a field emission electron source emitted through an electroconductive thin film
The oxidation of the porous semiconductor layer,
Main oxidation treatment for oxidizing the porous semiconductor layer at a relatively low temperature
The main oxidation treatment process before and after the main oxidation process.
At least on the other hand, the acid of the porous semiconductor layer is thermally oxidized.
It is characterized by having an auxiliary oxidation treatment process for
Strong electric field drift by oxidizing porous semiconductor layer by rapid heating method
Process temperature lower than when forming a layer
It can reduce the restrictions on the material of the conductive substrate,
Field emission type electron source that can increase the area and reduce the cost
Can be provided.
At least one of before and after, the thermal oxidation method
An auxiliary oxidation process for oxidizing the porous semiconductor layer should be provided.
Thereby, the electron emission efficiency can be increased. Claim
Item 16 is a conductive substrate, one surface side of the conductive substrate
Electric field composed of oxidized porous semiconductor layer formed on
Lift layer and a conductive layer formed on the strong electric field drift layer.
And a thin film, wherein the conductive thin film is
Is injected from the conductive substrate by applying a voltage
Electrons drift in the strong electric field drift layer and pass through the conductive thin film.
A method for manufacturing a field emission electron source emitted as
In oxidizing the above porous semiconductor layer, at a relatively low temperature
Comprising a main oxidation process of oxidizing the porous semiconductor layer,
Prior to the main oxidation process, the porous
A pre-oxidation process for oxidizing the semiconductor layer.
The feature is that the porous semiconductor layer is oxidized by the rapid heating method
Process temperature compared to forming a strong electric field drift layer
Temperature can be reduced, and the material of the conductive substrate is restricted.
Electric field emission that can reduce the size and increase the area and cost
Can provide morphism type electron source, even deer, the main oxidation
Before the processing step, the porous semiconductor layer is oxidized with an oxidizing solution.
By providing a pre-oxidation process for oxidizing
Release efficiency can be increased.

According to a seventeenth aspect of the present invention, a strong electric field drift layer comprising a conductive substrate, an oxidized porous semiconductor layer formed on one surface side of the conductive substrate, and a strong electric field drift layer formed on the strong electric field drift layer An electric field emission, wherein electrons injected from the conductive substrate are drifted through the strong electric field drift layer and emitted through the conductive thin film by applying a voltage with the conductive thin film as a positive electrode with respect to the conductive substrate. In the method of manufacturing a porous electron source, the oxidation of the porous semiconductor layer is performed by oxidizing the porous semiconductor layer with an oxidizing solution before oxidizing the porous semiconductor layer by a thermal oxidation method. It is characterized by having a treatment process, wherein the porous semiconductor layer whose surface has been oxidized by the oxidizing solution is subjected to the thermal oxidation method, so that the rapid heating method is applied immediately after the anodic oxidation treatment. Since less hydrogen is mixed into the strong electric field drift layer than in the conventional method, the decrease in electron emission efficiency due to the change over time in the distribution of hydrogen as in the conventional case is small, and the oxide film tends to be dense and the withstand voltage is high. Become. Claim 18
The invention comprises a conductive substrate, a strong electric field drift layer formed of an oxidized porous semiconductor layer formed on one surface side of the conductive substrate, and a conductive thin film formed on the strong electric field drift layer Oxidized porous semiconductor , a strong electric field drift layer
The layer is formed at least on the surface of the columnar polycrystalline silicon formed on the one surface side of the conductive substrate, the microcrystalline silicon layer including a nanostructure interposed between the polycrystalline silicon, and the surface of the microcrystalline silicon layer. A silicon oxide film having a thickness smaller than the crystal grain size of the microcrystalline silicon layer. Electrons injected from the conductive substrate are strongly applied by applying a voltage to the conductive thin film as a positive electrode with respect to the conductive substrate. A method for manufacturing a field emission type electron source that drifts an electric field drift layer and is emitted through a conductive thin film, wherein the porous semiconductor layer is oxidized by oxidizing the porous semiconductor layer by a thermal oxidation method. It is characterized by comprising a pre-oxidation treatment step of oxidizing the porous semiconductor layer with an oxidizing solution, wherein the porous semiconductor layer whose surface has been oxidized by the oxidizing solution is subjected to a thermal oxidation method. As compared with the case where the rapid heating method is applied immediately after the anodic oxidation treatment, the mixing of hydrogen into the strong electric field drift layer is small, so that the electron emission due to the temporal change of the distribution of hydrogen as in the conventional case. The decrease in efficiency is small, the oxide film tends to be dense, and the withstand voltage is high. In addition, it is possible to provide a field emission type electron source that has a small degree of vacuum dependence of electron emission characteristics and can stably emit electrons without generating a popping phenomenon during electron emission.

[0027] The invention of claim 19 is the invention of claim 13 or
In the invention according to claim 15, a pre-oxidation step of oxidizing the porous semiconductor layer with an oxidizing solution is provided before the main oxidation step and the auxiliary oxidation step, so that the electron emission efficiency is improved. be able to.

According to a twentieth aspect of the present invention, in the ninth aspect of the invention, the main oxidizing step is a step of irradiating the porous semiconductor layer with ultraviolet light in a gas atmosphere containing at least one of oxygen and ozone. Exposing the porous semiconductor layer to plasma in a gas atmosphere containing at least one of ozone and ozone, heating the porous semiconductor layer in a gas atmosphere containing at least ozone, and irradiating the porous semiconductor layer with ultraviolet light. And heating the porous semiconductor layer and heating the porous semiconductor layer while irradiating the porous semiconductor layer with ultraviolet light in a gas atmosphere containing at least one of oxygen and ozone. Since the porous semiconductor layer is oxidized by the two treatments, the porous semiconductor layer is oxidized by a rapid heating method to form a strong electric field drift layer. It is possible to increase the electron emission efficiency as compared with the case, and to form the strong electric field drift layer at a lower temperature than in the case where the porous semiconductor layer is oxidized by the rapid heating method to form the strong electric field drift layer. As a result, the process temperature is lowered, the restriction on the conductive substrate is reduced, and the area and cost can be easily reduced.

According to a twenty-first aspect of the present invention, a strong electric field drift layer comprising a conductive substrate, an oxidized porous semiconductor layer formed on one surface side of the conductive substrate, and a high electric field drift layer formed on the strong electric field drift layer A conductive thin film, wherein the electron injected from the conductive substrate drifts through the strong electric field drift layer and is emitted through the conductive thin film by applying a voltage with the conductive thin film as a positive electrode with respect to the conductive substrate. A method of manufacturing a type electron source, comprising: forming a conductive thin film, irradiating ultraviolet light in a gas atmosphere containing at least one of oxygen and ozone, and performing plasma treatment in a gas atmosphere containing at least one of oxygen and ozone. Exposure, heat treatment in a gas atmosphere containing at least ozone, heat treatment while irradiating ultraviolet light, gas atmosphere containing at least one of oxygen and ozone At least one of a process of irradiating with ultraviolet light and a process of heating is performed. By performing the process, it is possible to remove contamination by organic substances in a process before the process, and to improve an electron emission efficiency. Can be increased.

According to a twenty-second aspect of the present invention, in the twentieth or twenty-first aspect of the present invention, at least one of before and after the main oxidation treatment step, an auxiliary oxidation for oxidizing the porous semiconductor layer by a thermal oxidation method. Since the process is provided, the electron emission efficiency can be increased.

The invention of claim 23 is the invention of claim 20 or claim 21, in at least one of the previous and subsequent of the main oxidation process, the auxiliary oxidation process for oxidizing the porous semiconductor layer by an acid Since the process is provided, the electron emission efficiency can be increased.

The invention of claim 24 is the invention of claim 20 or claim 21, in front of the main oxidation process,
Since a pre-oxidation treatment step of oxidizing the porous semiconductor layer with an oxidizing solution is provided, hydrogen atoms that terminate atoms on the surface of the porous semiconductor layer when the porous semiconductor layer is formed by anodic oxidation treatment are removed. Since the oxygen atoms are replaced by the oxidizing solution, the amount of hydrogen contained in the strong electric field drift layer can be reduced, and the temporal change in the distribution of hydrogen in the strong electric field drift layer can be reduced. And the stability over time is improved . The invention of claim 25
Is formed on one surface side of the conductive substrate and the conductive substrate
A strong electric field drift layer comprising an oxidized porous semiconductor layer;
A conductive thin film formed on the strong electric field drift layer.
The voltage is applied to the conductive thin film as a positive electrode with respect to the conductive substrate.
When applied, the electrons injected from the conductive substrate
Drift the electric field drift layer and emit through the conductive thin film
A method for producing a field emission type electron source,
When oxidizing the semiconductor layer, the porous
A main oxidation process for oxidizing the semiconductor layer;
The treatment process includes a gas containing at least one of oxygen and ozone.
Irradiating the porous semiconductor layer with ultraviolet light in a gas atmosphere
Gas atmosphere containing at least one of oxygen and ozone
Exposure of the porous semiconductor layer to plasma with less
In the gas atmosphere containing ozone, the porous semiconductor layer
Heat treatment, irradiating the porous semiconductor layer with ultraviolet light
Together with the treatment of heating the porous semiconductor layer, oxygen and
The above-mentioned porosity in a gas atmosphere containing at least one of ozone
Irradiates the porous semiconductor layer with ultraviolet light and
At least one of the processes for heating the body layer
The porous semiconductor layer is oxidized, and the main oxidation treatment is performed.
Before and / or after the process, the thermal oxidation method
An auxiliary oxidation process for oxidizing the porous semiconductor layer is provided.
Characterized in that the porous semiconductor layer is heated by a rapid heating method.
Compared to forming a strong electric field drift layer by oxidation
Can increase the emission efficiency of the semiconductor
The layer is oxidized by the rapid heating method to form a strong electric field drift layer.
Form a strong electric field drift layer at a lower temperature than when forming
The process temperature can be reduced to lower the conductive substrate
Less restrictions, large area and low cost
Become. According to a twenty-sixth aspect of the present invention, a conductive substrate and a conductive substrate
Of the oxidized porous semiconductor layer formed on one side of
A strong electric field drift layer, and a layer formed on the strong electric field drift layer.
And a conductive thin film on the conductive substrate.
The conductive substrate by applying a voltage as the positive electrode
Injected electrons drift from the strong electric field drift layer and conduct.
For producing field emission electron source emitted through conductive thin film
When oxidizing the porous semiconductor layer,
A main oxidation treatment for oxidizing the porous semiconductor layer at a relatively low temperature.
And the main oxidation treatment step includes a small amount of oxygen and ozone.
In a gas atmosphere containing at least one, the porous semiconductor layer
UV irradiation treatment, at least one of oxygen and ozone
The porous semiconductor layer into plasma in a gas atmosphere containing
Abstract treatment, at least in a gas atmosphere containing ozone
Processing for heating the porous semiconductor layer, the porous semiconductor layer
And irradiating the porous semiconductor layer with ultraviolet light.
Gas containing at least one of oxygen and ozone
Irradiating the porous semiconductor layer with ultraviolet light in a gas atmosphere
Of the treatments for heating the porous semiconductor layer,
The porous semiconductor layer is oxidized by at least one treatment.
And at least one of before and after the main oxidation process.
On the other hand, an auxiliary acid that oxidizes the porous semiconductor layer with an acid
A porous semiconductor layer.
Oxidized by rapid heating method to form strong electric field drift layer
Can increase the electron emission efficiency compared to
In addition, the porous semiconductor layer is oxidized by the rapid heating method to
Field drift at a lower temperature than when forming a field drift layer.
Layer can be formed and the process temperature can be reduced.
As a result, the restrictions on the conductive substrate are reduced, and
Cost reduction becomes easy. The invention according to claim 27 is a conductive group
Plate and oxidized porosity formed on one surface side of conductive substrate
Electric field drift layer made of a porous semiconductor layer and the strong electric field drift layer.
And a conductive thin film formed on the shaft layer.
To apply a voltage to the conductive substrate as a positive electrode.
Electrons injected from a more conductive substrate become a strong electric field drift layer
Field emission type that drifts and is emitted through a conductive thin film
A method for producing an electron source, comprising oxidizing the porous semiconductor layer.
In doing so, the porous semiconductor layer is oxidized at a relatively low temperature.
Main oxidation treatment step, wherein the main oxidation treatment step
Above in a gas atmosphere containing at least one of oxygen and ozone
Processing of irradiating ultraviolet light to the porous semiconductor layer, the oxygen and ozone
The above porous semiconductor in a gas atmosphere containing at least one of
Exposing the body layer to plasma, including at least ozone
A process of heating the porous semiconductor layer in a gas atmosphere;
The porous semiconductor layer is irradiated with ultraviolet light and
Process for heating the porous semiconductor layer, less oxygen and ozone
UV light on the porous semiconductor layer in a gas atmosphere containing
Irradiate light and heat the porous semiconductor layer
The porous material is obtained by at least one of the processes.
The semiconductor layer is oxidized and oxidized before the main oxidation process.
Pre-oxidation treatment for oxidizing the porous semiconductor layer with a solution
Process, the porous semiconductor layer is rapidly added.
When oxidizing by a thermal method to form a strong electric field drift layer
Can increase the electron emission efficiency compared to
The porous semiconductor layer is oxidized by the rapid heating method to
Strong electric field drift layer at lower temperature than when forming a drift layer
The process temperature can be reduced
Less restrictions on conductive substrates, larger area and lower cost
It becomes easier. Moreover, before the main oxidation treatment step,
An acid before oxidizing the porous semiconductor layer with an oxidizing solution
The porous semiconductor layer is subjected to an anodic oxidation treatment
Atoms formed on the surface of the porous semiconductor layer
Terminating hydrogen atoms are placed on oxygen atoms by oxidizing solution.
Water contained in the strong electric field drift layer
And the strong electric field
Reduction of temporal change of hydrogen distribution in drift layer
And the stability over time is improved.

The invention of claim 28 is the invention of claim 22 or claim 23 or claim 25 or claim 26, before the main oxidation process and the auxiliary oxidation process, the by oxidizing solution Since the pre-oxidation process for oxidizing the porous semiconductor layer is provided, hydrogen atoms that terminate atoms on the surface of the porous semiconductor layer when the porous semiconductor layer is formed by anodic oxidation are treated by an oxidizing solution. Since it is replaced by oxygen atoms, the amount of hydrogen contained in the strong electric field drift layer can be reduced, and the temporal change in the distribution of hydrogen in the strong electric field drift layer can be reduced. Stability is improved.

According to a twenty- ninth aspect of the present invention, in the invention of the eighth to twenty- eighth aspects, the porous semiconductor layer is made of porous single-crystal silicon, so that the strong electric field drift layer is made of Si.
By having an oxide film with high density close to the structure of O ₂ or SiO ₂ , the density and film quality of the oxide film are improved, the electron emission efficiency is improved, and the withstand voltage is increased.

According to a thirtieth aspect of the present invention, in the invention of the eighth to twenty- eighth aspects, the porous semiconductor layer is made of porous polycrystalline silicon.
By having an oxide film with high density close to the structure of O ₂ or SiO ₂ , the density and film quality of the oxide film are improved, the electron emission efficiency is improved, and the withstand voltage is increased.

The invention of claim 31 is characterized in that, in the invention of claims 8 to 30 , the conductive substrate is an n-type silicon substrate.

According to a thirty-second aspect of the present invention, in any one of the eighth to thirty aspects of the present invention, the conductive substrate comprises an insulating substrate and a conductive film formed on one surface side of the insulating substrate. As a feature, the area can be increased and the cost can be reduced as compared with the invention of claim 24.

A thirty-third aspect of the present invention is characterized in that, in the thirty-second aspect , the insulating substrate is made of a glass substrate.

A thirty-fourth invention is characterized in that, in the thirty-second invention, the insulating substrate is made of a ceramic substrate.

According to a thirty-fifth aspect of the present invention, in any of the eighth to thirty-fourth aspects, the porous semiconductor layer is formed by subjecting the semiconductor layer to an anodic oxidation treatment.

According to a thirty- sixth aspect, in the tenth or twelfth aspect , the acid is selected from the group consisting of nitric acid, sulfuric acid, and aqua regia. This is a preferred embodiment.

According to a thirty-seventh aspect of the present invention, the fourteenth aspect, the sixteenth aspect, the seventeenth aspect, the eighteenth aspect, the nineteenth aspect, the twenty-fourth aspect, the twenty-fourth aspect, and the twenty-seventh aspect are provided.
In the invention of Item 28 , the oxidizing solution comprises nitric acid, sulfuric acid,
This is a preferred embodiment, characterized by comprising one or more oxidizing agents selected from the group consisting of hydrochloric acid and aqueous hydrogen peroxide.

The invention of claim 38 is the invention of claim 37, said oxidizing solvent solution, because it is heated to the oxidation speed increases, it is possible to shorten the processing time by the oxidizing solution , Improving the throughput.

According to a thirty-ninth aspect of the present invention, there is provided a space between the field emission type electron source according to any one of the first to seventh aspects and a field emission type electron source which is disposed to face the field emission type electron source. Is maintained in a vacuum, a collector electrode provided on the surface of the face plate facing the field emission electron source, and a field emission type provided on the collector electrode facing the field emission electron source. 7. A field emission type device according to claim 1, further comprising: a phosphor layer that emits light in a visible light region by receiving an electron beam from an electron source. Since an electron source is provided, the area can be increased and the cost can be reduced.

[0045]

(Embodiment 1) FIG. 1 is a schematic sectional view of a field emission type electron source 10 according to this embodiment, and FIGS.
(D) is a sectional view of a main step in the method for manufacturing the field emission electron source 10. In this embodiment, a single-crystal n-type silicon substrate 1 having a resistivity relatively close to that of a conductor ((100) having a resistivity of approximately 0.1 Ωcm) is used as a conductive substrate.
Substrate).

In the field emission type electron source 10 of the present embodiment, as shown in FIG. 1, a non-doped polycrystalline silicon layer 3 is formed A strong electric field drift layer 6 is formed, and a conductive thin film 7 made of a gold thin film is formed on the strong electric field drift layer 6. An ohmic electrode 2 is formed on the back surface of the n-type silicon substrate 1.

In the present embodiment, the n-type silicon substrate 1 is used as the conductive substrate. The conductive substrate constitutes the negative electrode of the field emission electron source 10 and has the strong electric field drift in vacuum. It supports the layer 6 and injects electrons into the strong electric field drift layer 6. Therefore, the conductive substrate is used for the field emission type electron source 10.
3 is not limited to the n-type silicon substrate, but may be a metal substrate of chromium or the like.
As shown in FIG. 1, a conductive film (for example, IT
(O film) 12 may be formed. When a substrate having the conductive film 12 formed on one surface of the insulating substrate 11 is used, compared with a case where a semiconductor substrate is used,
The area and cost of the electron source can be reduced.

The strong electric field drift layer 6 is formed by oxidizing porous polycrystalline silicon with an acid.
This is a layer into which electrons are injected when a voltage is applied between the conductive substrate and the conductive thin film 7. The strong electric field drift layer 6
It is a polycrystalline body composed of a large number of grains, and each grain has a nanometer unit structure (hereinafter, referred to as an oxide film)
Nanostructures). Electrons injected into the strong electric field drift layer 6 do not collide with the nanostructure (that is,
In order to reach the surface of the strong electric field drift layer 6 (without electron scattering), the size of the nanostructure needs to be smaller than about 50 nm, which is the mean free path of electrons in single crystal silicon. It is. The size of the nanostructure is specifically smaller than 10 nm, preferably 5 nm.
Those smaller than nm are preferred.

In this embodiment, a gold thin film is used as the conductive thin film 7. The conductive thin film 7 constitutes the positive electrode of the field emission type electron source 10 and has a strong electric field drift layer 6. To apply an electric field. The electrons that reach the surface of the strong electric field drift layer 6 by the application of the electric field are emitted from the surface of the conductive thin film 7 by a tunnel effect. Therefore, the energy obtained by subtracting the work function of the conductive thin film 7 from the energy of the electron obtained by the DC voltage applied between the conductive substrate and the conductive thin film 7 becomes the ideal energy of the emitted electrons. It is desirable that the work function of the conductive thin film 7 be as small as possible. In the present embodiment, gold is used as the material of the conductive thin film 7. However, the material of the conductive thin film 7 is not limited to gold, and may be any material having a small work function. ,
Chromium, tungsten, nickel, platinum or the like may be used. Here, the work function of gold is 5.10 eV, the work function of aluminum is 4.28 eV, the work function of chromium is 4.50 eV, and the work function of tungsten is 4.55 eV.
The work functions of V and nickel are 5.15 eV, and the work functions of platinum are 5.65 eV.

Although the conductive thin film 7 is a single layer of a gold thin film, it may be composed of at least two thin layers laminated in the thickness direction. When the conductive thin film 7 is composed of two thin film layers, for example, gold or the like can be used as the material of the upper thin film layer. As a material of the lower thin film layer (the thin film layer on the strong electric field drift layer 6 side), for example, chromium, nickel, platinum, titanium, iridium, or the like can be used.

Hereinafter, the manufacturing method will be described with reference to FIG.

First, an ohmic electrode 2 is formed on the back surface of an n-type silicon substrate 1, and then a non-doped polycrystalline silicon layer 3 having a thickness of about 1.5 μm is formed on the surface of the n-type silicon substrate 1.
Is formed, a structure as shown in FIG. 2A is obtained. The polycrystalline silicon layer 3 is formed by the LPCVD method under the conditions of a vacuum of 20 Pa, a substrate temperature of 640 ° C., and a monosilane gas flow rate of 0.6 L under standard conditions.
/ Min (600 sccm). Note that the polycrystalline silicon layer 3 may be formed by an LPCVD method or a sputtering method when the conductive substrate is a semiconductor substrate, or by performing an annealing process after forming an amorphous silicon film by a plasma CVD method. Crystallization may be performed to form a film. When the conductive substrate is a glass substrate on which a conductive thin film is formed, a polycrystalline silicon layer is formed by forming an amorphous silicon film on the conductive thin film by a CVD method and then annealing with an excimer laser. May be. Further, the method of forming a polycrystalline silicon layer on a conductive thin film is not limited to the CVD method. For example, CGS (Continuous Grain Silicon)
Alternatively, a catalytic CVD method or the like may be used.

After the non-doped polycrystalline silicon layer 3 is formed, an anodizing tank containing an electrolytic solution comprising a mixture of a 55 wt% aqueous hydrogen fluoride solution and ethanol in a ratio of about 1: 1 is used. A platinum electrode (not shown) is connected to the negative electrode, n
Type silicon substrate 1 (ohmic electrode 2) as a positive electrode
By performing anodic oxidation at a constant current while irradiating the polycrystalline silicon layer 3 with light, a porous polycrystalline silicon layer 4 is formed, and a structure as shown in FIG. 2B is obtained.
In the present embodiment, the conditions of the anodic oxidation treatment are such that the current density is constant at 10 mA / cm ² , the anodic oxidation time is 30 seconds, and the surface of the polycrystalline silicon layer 3 is anodized by a 500 W tungsten lamp during the anodic oxidation. Light irradiation was performed. As a result, in this embodiment, the porous polycrystalline silicon layer 4 having a thickness of about 1 μm was formed. In the present embodiment, a part of the polycrystalline silicon layer 3 is made porous, but the entire polycrystalline silicon layer 3 may be made porous.

After the above-described anodizing treatment is completed, the electrolytic solution is removed from the above-described anodizing tank, and about 10% of dilute nitric acid is newly added to the anodizing tank as an electrolyte solution.
Using the anodic oxidation tank containing the diluted nitric acid, a platinum electrode (not shown) is used as a negative electrode, and the n-type silicon substrate 1 (ohmic electrode 2) is used as a positive electrode, and a constant current is applied to form the porous polycrystalline silicon layer 4. By oxidation, the structure shown in FIG. 2C is obtained. Reference numeral 6 in FIG. 2C denotes a strong electric field drift layer 6 formed by oxidizing the porous polycrystalline silicon layer 4 with an acid (in the present embodiment, the above-mentioned diluted nitric acid).

Here, the porous polycrystalline silicon layer 4
When oxidizing with dilute nitric acid, if the hole is h ⁺ and the electron is e ⁻ , the following reaction is considered to have occurred. Negative electrode side: HNO ₃ + 3H ⁺ → NO + 2H ₂ O + 3h ⁺ Positive electrode side: 3h ⁺ + Si + 2H ₂ O → SiO ₂ + 4H ⁺ + e ^- The process of forming the strong electric field drift layer 6 by this reaction will be described with reference to the schematic diagram shown in FIG. Due to the above reaction, the holes h ⁺ generated in the porous polycrystalline silicon layer 4 as shown in FIG. Moving to the inner surface of the micropores formed in the crystalline silicon layer 4)
As shown in FIG. 4 (b), a thin silicon oxide film 62 is formed.
The surface of the polycrystalline silicon 61 is covered with the thin silicon oxide film 62 as shown in FIG.

The ratio of dilute nitric acid and the current value of the constant current may be appropriately changed depending on the thickness and film quality of the porous polycrystalline silicon layer 4 to be oxidized. Further, when this oxidation is performed, the voltage between the positive electrode and the negative electrode (potential voltage) increases. However, when managing the time point at which the oxidation is terminated by this potential voltage, the potential voltage is set to several volts to several tens of volts, for example. May be appropriately selected within the range described above. further,
When light irradiation is performed at the time of oxidation, conditions for light irradiation may be appropriately selected, and the temperature of diluted nitric acid may be appropriately selected.

By the way, in the strong electric field drift layer 6, it is considered that the surface of the silicon microcrystal having a nanostructure formed by the above-described anodic oxidation treatment is oxidized by dilute nitric acid. In short, in the present embodiment, as shown in FIG. It is considered that the microcrystalline silicon layer 63 is interposed between the columnar polycrystalline silicon and a silicon oxide film 64 formed on the surface of the microcrystalline silicon layer 63.

In this embodiment, since the porous polycrystalline silicon layer 4 is oxidized with an acid, the porous polycrystalline silicon layer 4 is oxidized by a rapid heating method to form a strong electric field drift layer (the present invention). Those are Japanese Patent Application No. Hei 10-272340.
No., Japanese Patent Application No. 10-272342, Japanese Patent Application No. 10-271
876), the process temperature is lower than in the case described above, the material of the conductive substrate is less restricted,
It is possible to provide a field emission type electron source capable of increasing the area and reducing the cost. Moreover, since the porous polycrystalline silicon layer 4 can be oxidized by wet processing subsequent to the anodic oxidation processing, the process can be simplified as compared with the case where oxidation is performed by rapid thermal oxidation after the anodic oxidation processing.

After the strong electric field drift layer 6 is formed, a conductive thin film 7 made of a gold thin film is formed on the strong electric field drift layer 6 by, for example, vapor deposition to obtain the structure shown in FIG. 2D (FIG. 1). Is obtained. Here, in the present embodiment, the thickness of the conductive thin film 7 is set to about 10 n.
m, but this film thickness is not particularly limited. The field emission electron source 10 has a diode in which the conductive thin film 7 is used as a positive electrode (anode) of the electrode and the ohmic electrode 2 is used as a negative electrode (cathode). In the present embodiment, the conductive thin film 7 is formed by vapor deposition, but the method of forming the conductive thin film 7 is not limited to vapor deposition.
For example, a sputtering method may be used.

In the field emission type electron source 10 of the present embodiment,
It is considered that electron emission occurs in the following model. That is, as shown in FIG. 6, a collector electrode 21 is arranged at a position facing the conductive thin film 7, and a DC voltage Vps is applied between the conductive thin film 7 and the ohmic electrode 2;
DC voltage Vc between collector electrode 21 and conductive thin film 7
When the DC voltage applied to the conductive thin film 7 as a positive electrode with respect to the n-type silicon substrate 1 reaches a predetermined value (critical value), heat is applied to the strong electric field drift layer 6 from the n-type silicon substrate 1 side. Electrons e ^- are injected by the mechanical excitation. On the other hand, since the electric field applied to the strong electric field drift layer 6 is almost applied to the silicon oxide film 64 (see FIG. 5), the injected electrons are accelerated by the strong electric field applied to the silicon oxide film 64, and 6 drifts toward the surface in the direction of arrow A in FIG. 5 (toward the upward direction in FIG. 5), through the oxide layer on the outermost surface of the strong electric field drift layer 6. Then, the conductive thin film 7 is tunneled and released into a vacuum.

The field emission electron source manufactured by the above-described manufacturing method is disclosed in Japanese Patent Application No. 10-272340,
Japanese Patent Application No. 10-272342, Japanese Patent Application No. 10-27187
As in the field emission type electron source proposed in No. 6, the electron emission characteristics have a small dependence on the degree of vacuum and can stably emit electrons without generating a popping phenomenon during electron emission. In addition to a semiconductor substrate such as a single crystal silicon substrate, a conductive film (for example, ITO
It is possible to use a substrate on which a film has been formed.
Compared with the Spindt-type electrode, the area of the electron source can be increased and the cost can be reduced.

In this embodiment, the anodic oxidation treatment
The oxidation with the acid after the anodic oxidation treatment is performed in the same anodic oxidation tank, but it goes without saying that it may be performed in a separate anodic oxidation tank.

(Embodiment 2) The structure and manufacturing method of the field emission type electron source of this embodiment are substantially the same as those of Embodiment 1, and after the anodic oxidation treatment described in Embodiment 1 is completed, The electrolytic solution was removed from the oxidation tank, and about 10% of dilute sulfuric acid was newly added as an electrolyte solution to the anodic oxidation tank. Thereafter, the platinum electrode (shown in FIG. Is a negative electrode and the n-type silicon substrate 1 (ohmic electrode 2) as a positive electrode, except that the porous polycrystalline silicon layer 4 is oxidized by passing a constant current. That is, in the present embodiment, the surface of the silicon microcrystal having a nanostructure formed by the anodic oxidation treatment is oxidized by dilute sulfuric acid.

Here, the porous polycrystalline silicon layer 4
When oxidizing with sulfuric acid, if the holes are h ⁺ and the electrons are e ⁻ , the following reaction is considered to have occurred. Negative electrode side: H ₂ SO ₄ + 2H ⁺ → SO ₂ + 2H ₂ O + 2h ⁺ Positive electrode side: 2h ⁺ + Si + 2H ₂ O → SiO ₂ + 4H ⁺ + 2e
^- The current value of the ratio and the current of the dilute sulfuric acid, may be changed appropriately by thickness and film quality of the porous polycrystalline silicon layer 4 to be oxidized. Further, when this oxidation is performed, the voltage between the positive electrode and the negative electrode (potential voltage) increases. However, when managing the time point at which the oxidation is terminated by this potential voltage, the potential voltage is set to several volts to several tens of volts, for example. May be appropriately selected within the range described above. Furthermore, when light irradiation is performed during oxidation, the conditions for light irradiation may be appropriately selected, and the temperature of dilute sulfuric acid may be appropriately selected.

Next, a specific example of the manufacturing method described in this embodiment will be described.

The n-type silicon substrate 1 has a resistivity of 0.01 to 0.02 Ωcm and a thickness of 525 μm (10
0) A substrate was used. The polycrystalline silicon layer 3 (see FIG. 2A) is formed by an LPCVD method.
The degree of vacuum was 20 Pa, the substrate temperature was 640 ° C., and the flow rate of the monosilane gas was 0.6 L / min (600 scc
m).

In the anodic oxidation treatment, 55 wt.
% Of an aqueous solution of hydrogen fluoride and ethanol were mixed at approximately 1: 1. The anodic oxidation treatment is performed so that only the region of the surface of the polycrystalline silicon layer 3 having a diameter of 10 mm is in contact with the electrolytic solution, the other portions are sealed so as not to contact the electrolytic solution, and the platinum electrode is immersed in the electrolytic solution. While irradiating the polysilicon layer 3 with light at a constant light power using a 500 W tungsten lamp, a predetermined current was passed using the platinum electrode as the negative electrode and the n-type silicon substrate 1 (the ohmic electrode 2) as the positive electrode. Here, the current density was 30 mA / cm ²
And the processing time was 10 seconds.

After forming the porous polycrystalline silicon layer 4
In a 1 mol% sulfuric acid solution heated to 70 ° C.
1 mA with gold electrode as negative electrode and n-type silicon substrate 1 as positive electrode
/ Cm ^TwoIt was oxidized electrochemically at a constant current. Then water
After washing and drying, remove the oxidized porous polycrystalline silicon layer.
15 nm thick gold thin film on the strong electric field drift layer 6
Was formed by a vapor deposition method.

The field emission type electron source 10 manufactured as described above is introduced into a vacuum chamber (not shown), and a collector electrode 21 (emission electron source) is placed at a position facing the conductive thin film 7 as shown in FIG. (Collecting electrode), the degree of vacuum in the vacuum chamber is set to 5 × 10 ⁻⁵ Pa, and a DC voltage Vps is applied between the gold thin film 7 (positive electrode) and the ohmic electrode 2 (negative electrode). By applying a DC voltage Vc of 100 V between the conductive thin film 7 and the conductive thin film 7, the diode current Ips flowing between the conductive thin film 7 and the ohmic electrode 2 and the electric field emission type electron source 10 through the conductive thin film 7 FIG. 7 shows the measurement result of the emission electron current Ie flowing between the collector electrode 21 and the conductive thin film 7 by the emitted electron e ⁻ (the dashed line in FIG. 6 indicates the emission electron flow). . Here, the horizontal axis of FIG. 7 indicates the value of the DC voltage Vps, and the vertical axis indicates the current density. In FIG.
Is shown.

As can be seen from FIG. 7, when the DC voltage Vps is 20 V, the emission electron current Ie of 1 μA / cm ² is obtained.
was gotten. Therefore, although only the low-temperature (70 ° C.) oxidation treatment step (oxidation step using sulfuric acid) is performed, the electron emission current Ie is observed. Even if a substrate requiring a low-temperature process is used, a desired electron source can be manufactured.

(Embodiment 3) The basic structure and manufacturing method of this embodiment are substantially the same as those of Embodiment 1, and after the above-described anodizing treatment is completed, the electrolytic solution is removed from the above-described anodizing tank. The difference is that aqua regia (concentrated hydrochloric acid: concentrated nitric acid = 3: 1) is supplied as an electrolyte solution to the anodizing tank to oxidize the porous polycrystalline silicon layer 4 with the aqua regia. Since silicon gradually oxidizes in aqua regia, in this embodiment,
The surface of the silicon microcrystal is oxidized by aqua regia that has penetrated into the pores of the porous polycrystalline silicon layer 4.

In each of the first to third embodiments, the porosity of the porous polycrystalline silicon layer 4 is made substantially uniform in the thickness direction while the current density during the anodic oxidation treatment is kept constant. May be changed so that a porous polycrystalline silicon layer having a high porosity and a porous polycrystalline silicon layer having a low porosity are alternately laminated, or the porosity is continuous in the thickness direction. The structure may be changed.

In each of the first to third embodiments, the strong electric field drift layer 6 is formed by oxidizing the porous polycrystalline silicon layer with an acid. However, the single crystal silicon is made porous by anodizing. The strong electric field drift layer may be formed by oxidizing the formed porous single crystal silicon with an acid.

(Embodiment 4) Embodiments 1-3
All field emission electron sources 10 are formed by anodizing.
The formed porous semiconductor layer (porous polycrystalline silicon layer 4 or
Or porous single-crystal silicon) with acid
Therefore, the strong electric field drift layer 6 is formed. But
In the first to third embodiments, the electrolytic solution is used in the anodizing treatment.
Using a mixture of aqueous hydrogen fluoride and ethanol
The silicon atoms in the porous semiconductor layer are hydrogen atoms
The strong electric field drift layer
6 contains a relatively large amount of hydrogen and the distribution of hydrogen atoms
Changes over time, resulting in the stability of electron emission efficiency over time.
May be worse. For example, if the conductive thin film 7 has a strong electric field
Such as when patterned on the lift layer 6
When hydrogen atoms escape from the electric field drift layer 6,
The aging stability may be deteriorated. Also, porous semiconductor
That the silicon atoms in the layer are terminated by hydrogen atoms
With, SiO _TwoA dense oxide film like
It was bad.

On the other hand, in the present embodiment, the porous semiconductor layer (porous polycrystalline silicon layer 4 or porous single crystal silicon) formed by the above-described anodic oxidation treatment is treated with an acid (eg, dilute nitric acid, Before being oxidized by sulfuric acid or aqua regia (that is, before electrochemically forming a silicon oxide film), the porous semiconductor layer is oxidized for a period of time sufficient to oxidize the extreme surface of the porous semiconductor layer. by immersion in an oxidizing solvent solution, and substituting the hydrogen atoms terminating the silicon atom to an oxygen atom. Here, as the oxidizing solvent solution, nitric acid (HNO _3), sulfuric acid (H ₂ SO _4), hydrochloric acid (HCl),
It is desirable to use one or more oxidizing agents selected from the group consisting of aqueous hydrogen peroxide (H ₂ O ₂ ).

[0076] Thus, a strong electric field drift layer 6 in the field emission electron source 10 of this embodiment shown in FIG. 8, formed by oxidizing the acid pole surface a porous semiconductor layer is oxidized by the oxidizing dissolved solution because it is a hydrogen atom that the porous semiconductor layer terminating the atoms on the surface of the porous semiconductor layer in forming the anodic oxidation treatment, because they are replaced by an oxygen atom by oxidation solvent solution, strong The hydrogen content in the electric field drift layer 6 can be reduced, and the temporal change in the distribution of hydrogen in the strong electric field drift layer 6 can be reduced, so that the temporal stability is improved. Furthermore, in the present embodiment, since the oxide film obtained by the porous semiconductor layer is oxidized by the acid tends to structure close to the structure or the SiO ₂ structure of SiO _2, improved denseness and film quality of the oxide film,
The electron emission efficiency is improved, and the dielectric strength is increased. Here, the function of the strong electric field drift layer 6 is the same as that of the strong electric field drift layer 6 of the first embodiment.

[0077] Incidentally, by heating the oxidizing solvent solution,
It is possible to shorten the processing time of the oxidation treatment with an oxidizing solvent solution, it is possible to improve the throughput. Also,
The conductive substrate may be a substrate in which a conductive film (for example, an ITO film) 12 is formed on one surface of an insulating substrate 11 such as a glass substrate (or a ceramic substrate) as shown in FIG. When a substrate in which the conductive film 12 is formed on one surface of the insulating substrate 11 is used, the area of the electron source can be increased and the cost can be reduced as compared with the case where a semiconductor substrate is used.

Next, an example of a method of manufacturing the field emission type electron source according to the present embodiment will be described with reference to FIG. Therefore, the same components as those in the first embodiment are denoted by the same reference numerals, and the similar steps will be described briefly.

In the manufacturing method according to the present embodiment, the ohmic electrode 2
Is formed on the surface of the n-type silicon substrate 1.
LPCVD of non-doped polycrystalline silicon layer 3 of 5 μm
By forming by the method, a structure as shown in FIG. 10A is obtained. In this embodiment, the conductive substrate has a resistivity of 0.01 to 0.02 Ωcm and a thickness of 52
A 5 μm n-type silicon substrate 1 ((100) substrate) is used.

Thereafter, a platinum electrode (not shown) was used by using an anodic oxidation tank containing an electrolytic solution composed of a mixture of a 55 wt% aqueous solution of hydrogen fluoride and ethanol in a ratio of about 1: 1.
Is used as a negative electrode, the n-type silicon substrate 1 (ohmic electrode 2) is used as a positive electrode, and the polycrystalline silicon layer 3 is subjected to anodic oxidation at a constant current while irradiating light, whereby a porous polycrystalline silicon layer 4 is formed. A structure as shown in FIG. 10 (b) is obtained. Here, the conditions of the anodic oxidation treatment are as follows: the current density is constant at 30 mA / cm ² , the anodic oxidation time is 10 seconds, and the surface of the polycrystalline silicon layer 3 is irradiated with light by a 500 W tungsten lamp during the anodic oxidation. Was done. In the present embodiment, the anodic oxidation treatment is performed in such a manner that only the region having a diameter of 10 mm in the surface of the polycrystalline silicon layer 3 is in contact with the electrolytic solution and the other portions are sealed so as not to contact the electrolytic solution. Was. In this embodiment, the entire polycrystalline silicon layer 3 is made porous.

Next, the extreme surface of the porous silicon layer 3 is oxidized.
It is oxidized by gender soluble liquid. In the present embodiment, as the oxidizing solvent solution, 115 ° C. and heated to a concentration of approximately 70%
Oxidation time was 10 minutes using nitric acid.

Thereafter, dilute nitric acid having a concentration of about 10% is newly added to the above-described anodic oxidation tank, and then, using the anodic oxidation tank containing the diluted nitric acid, a platinum electrode is used as a negative electrode and an n-type silicon substrate is used. By oxidizing the porous polycrystalline silicon layer 4 by passing a constant current using 1 as a positive electrode, the structure shown in FIG. 10C is obtained. 6 in FIG. 10 (c) indicates that the pole surface is oxidizing .
Porous polycrystalline silicon layer 4 of an acid oxidized by dissolved solution (in the present embodiment uses a dilute nitric acid mentioned above, may also be used dilute sulfuric acid or aqua regia) is formed by oxidizing the 3 shows a strong electric field drift layer.

After the strong electric field drift layer 6 is formed, the field emission type electron source 10 having the structure shown in FIG. can get. Although the thickness of the conductive thin film 7 is set to 15 nm in the present embodiment, the thickness is not particularly limited.

(Embodiment 5) The basic configuration and manufacturing method of the field emission type electron source of this embodiment are substantially the same as those of Embodiment 4, and the strong electric field drift layer 6 in FIG. 4 (FIG. 10)
(B) the pole surface of the reference) after oxidized by oxidizing solvent liquid, it is characterized in that it is formed by oxidizing by rapid heating method. In the present embodiment, a single-crystal n having a resistivity relatively close to the resistivity of the conductor is used as the conductive substrate.
A silicon substrate 1 (for example, a (100) substrate having a resistivity of about 0.1 Ωcm) is used.

Since the field emission type electron source 10 of the present embodiment has the structure shown in FIG. 8 similarly to the fourth embodiment, the conductive thin film 7 is arranged in On the other hand, by applying a voltage as a positive electrode, n
Electrons injected from the silicon substrate 1 drift in the strong electric field drift layer 6 and are emitted through the conductive thin film 7. Further, also in the present embodiment, the strong electric field drift layer 6 has a dense oxide film with less mixing of hydrogen than in the related art. Here, the oxide film has a dense film close to the structure close to the structure or the SiO ₂ structure of SiO _2.

In the field emission type electron source 10 according to the present embodiment, however, the reduction of the electron emission efficiency due to the temporal change of the distribution of hydrogen as in the related art is caused by the small amount of hydrogen mixed into the strong electric field drift layer 6. Since the oxide film is small and the oxide film becomes denser than before, the dielectric strength is high.

In this embodiment, the strong electric field drift layer 6 is made of an oxidized porous polysilicon layer. However, the strong electric field drift layer 6 may be made of an oxidized porous single crystal silicon. Good.

Hereinafter, the manufacturing method will be described. Since the manufacturing method of this embodiment is substantially the same as that of the fourth embodiment, the description will be made with reference to FIG. 10 described in the fourth embodiment.

First, after an ohmic electrode 2 is formed on the back surface of the n-type silicon substrate 1, a non-doped polycrystalline silicon layer 3 as a semiconductor layer having a predetermined thickness (for example, 1.5 μm) is formed on the surface of the n-type silicon substrate 1. Is formed (film formation), a structure as shown in FIG. 10A is obtained. When the conductive substrate is a semiconductor substrate, the polycrystalline silicon layer 3 may be formed by, for example, an LPCVD method or a sputtering method, or may be formed by forming an amorphous silicon film by a plasma CVD method and then performing an annealing process. Crystallization may be performed to form a film. In addition, when the conductive substrate is a substrate in which a conductive thin film is formed on a glass substrate,
A polycrystalline silicon layer may be formed by forming amorphous silicon on a conductive thin film by a CVD method and then annealing the film with an excimer laser. The method for forming a polycrystalline silicon layer on a conductive thin film is not limited to the CVD method.
A Grain Silicon) method or a catalytic CVD method may be used.

After the non-doped polycrystalline silicon layer 3 is formed, an anodizing tank containing an electrolytic solution comprising a mixture of a 55 wt% aqueous solution of hydrogen fluoride and ethanol in a ratio of about 1: 1 is used. A platinum electrode (not shown) is connected to the negative electrode, n
Type silicon substrate 1 (ohmic electrode 2) as a positive electrode
By performing anodic oxidation treatment under predetermined conditions while irradiating the polycrystalline silicon layer 3, a porous polycrystalline silicon layer 4 is formed, and a structure as shown in FIG. 10B is obtained. Here, in the present embodiment, the conditions of the anodic oxidation treatment are as follows.
Although the light power applied to the surface of the substrate is constant and the current density is constant, this condition may be appropriately changed (for example, the current density may be changed).

[0091] After the anodic oxidation process described above has been completed, the very surface of the porous polycrystalline silicon layer 4 is oxidized by oxidizing solvent solution, a strong electric field drift layer 6 is formed by oxidizing by rapid heating method 10 (c) is obtained. In short, in the present embodiment, the hydrogen atoms of the porous polycrystalline silicon layer 4 terminates the porous polycrystalline silicon atoms of the silicon layer 4 at the time of forming the anodic oxidation treatment, the oxygen atom by oxidizing solvent solution Has been replaced. Here, as the oxidizing solvent solution, nitric acid (HNO _3), sulfuric acid (H ₂ SO _4), hydrochloric acid (HCl), hydrogen peroxide (H
It is desirable to use one or more oxidizing agents selected from the group consisting of ₂ O ₂ ).

After the strong electric field drift layer 6 is formed, a conductive thin film 7 made of a gold thin film is formed on the strong electric field drift layer 6 by, for example, vapor deposition, so that the structure shown in FIG. An electron source 10 is obtained. The thickness of the conductive thin film 7 is not particularly limited, and may be any thickness as long as electrons that have passed through the strong electric field drift layer 6 can tunnel. Further, in the present embodiment, the conductive thin film 7 is formed by vapor deposition, but the method of forming the conductive thin film 7 is not limited to vapor deposition, and for example, a sputtering method may be used. The field emission type electron source 10 has a diode in which the conductive thin film 7 has a positive electrode (anode) and the ohmic electrode 2 has a negative electrode (cathode).

[0093] Thus, according to the manufacturing method described above, rapid thermal oxidation (heat by rapid heating method after oxidation by the porous polycrystalline extreme surface layer of the silicon layer 4 formed by the anodic oxidation treatment oxidizing solvent solution (Oxidation treatment), the amount of hydrogen contained in the strong electric field drift layer 6 can be reduced, and a SiO ₂ structure or a dense oxide film close to the SiO ₂ structure can be formed. A field emission electron source having a small change in electron emission efficiency with time and a high withstand voltage can be realized.

The field emission electron source manufactured by the above-described manufacturing method is disclosed by the present inventors in Japanese Patent Application No. 10-27234.
As in the case of the field emission type electron source proposed in Japanese Patent Application No. 0, Japanese Patent Application No. 10-272342, the electron emission characteristics have a small dependence on the degree of vacuum and emit electrons stably without popping phenomenon at the time of electron emission. In addition to a semiconductor substrate such as a single crystal silicon substrate as a conductive substrate, a substrate on which a conductive film (for example, an ITO film) is formed on a glass substrate or the like can be used. In comparison, the area of the electron source can be increased and the cost can be reduced.

The field emission type electron source 10 was manufactured as an example by the method of manufacturing the field emission type electron source 10 described in this embodiment with reference to FIG. 10 under the following conditions.

The n-type silicon substrate 1 has a resistivity of 0.01 to 0.02 Ωcm and a thickness of 525 μm (10
0) A substrate was used. Polycrystalline silicon layer 3 (FIG. 10A)
The film formation conditions were as follows: LPCVD method, and the film formation conditions were as follows: the degree of vacuum was 20 Pa, the substrate temperature was 640 ° C., and the flow rate of monosilane gas was 0.6 L / min (600 s) under standard conditions.
ccm).

In the anodic oxidation, an electrolytic solution obtained by mixing a 55 wt% aqueous solution of hydrogen fluoride and ethanol at a ratio of about 1: 1 was used. The anodic oxidation is performed so that only the area of the surface of the polycrystalline silicon layer 3 having a diameter of 10 mm is in contact with the electrolytic solution, the other parts are sealed so as not to contact the electrolytic solution, and the platinum electrode is immersed in the electrolytic solution. While irradiating the polycrystalline silicon layer 3 with light at a constant optical power using a 500 W tungsten lamp, a predetermined current was passed using the platinum electrode as a negative electrode and the n-type silicon substrate 1 (ohmic electrode 2) as a positive electrode. Here, the current density was fixed at 30 mA / cm ² , and the processing time was 10 seconds.

[0098] As oxidizing solvent solution with nitric acid heated to 115 ° C. (70% concentration). Incidentally, by previously heating the oxidizing solvent solution, since the oxidation speed increases, oxidizing
It is possible to shorten the processing time by solvent solution.

The conditions for rapid thermal oxidation of the porous polycrystalline silicon layer 4 by the rapid heating method are as follows: the flow rate of oxygen gas is 0.3 L / min (300 sccm) under standard conditions, the oxidation temperature is 900 ° C., and the oxidation time is 1 hour. And The conductive thin film 7 was formed by a vapor deposition method and had a thickness of 15 nm.

The field emission type electron source 10 of this embodiment is introduced into a vacuum chamber (not shown), and a collector electrode 21 (radiation electron collection electrode) is placed at a position facing the conductive thin film 7 as shown in FIG. ) And set the degree of vacuum in the vacuum chamber to 5
As × 10 ^-5 Pa, the conductive thin film 7 (the positive electrode) while applying a DC voltage Vps between the ohmic electrode 2 (anode), between the collector electrode 21 and the conductive thin film 7 100
By applying a DC voltage Vc of V, the diode current I flowing between the conductive thin film 7 and the ohmic electrode 2 is increased.
The collector electrode 21 and the conductive thin film 7 are formed by ps and electrons e ⁻ emitted from the field emission type electron source 10 through the conductive thin film 7 (the dashed line in FIG. 11 indicates a radiated electron flow).
FIG. 12 shows the result of measurement of the emission electron current Ie flowing between. Here, the horizontal axis in FIG. 12 indicates the value of the DC voltage Vps, and the vertical axis indicates the current density. In FIG. 12, （() indicates the diode current Ips of the present embodiment, and ● () indicates the current value. 5 shows the emission electron current Ie of the example.

FIG. 12 also shows, as a comparative example, the results of similar measurements performed on an electron source in which all other conditions were the same without performing treatment with an oxidizing solution before rapid thermal oxidation. It is. That is, □ () in the figure indicates the diode current Ips of the comparative example, and ■ () indicates the emission electron current Ie of the comparative example.

As can be seen from FIG. 12, when the embodiment and the comparative example are compared, the emission electron current Ie is substantially the same, while the diode current Ips is lower in the embodiment. Since the electron emission efficiency is represented by the ratio Ie / Ips of the emission electron current Ie to the diode current Ips, it can be seen that the field emission electron source 10 of the present embodiment has a higher electron emission efficiency than the comparative example. . In the comparative example, the dielectric breakdown occurred when the DC voltage Vps was 22 V. However, in the present embodiment, the dielectric breakdown did not occur even when the DC voltage Vps was increased to 28 V. In short, the present example has a higher dielectric strength than the comparative example.

The conditions up to the formation of the porous polycrystalline silicon layer 4 were as described above, and the subsequent conditions were as follows to produce the field emission electron source 10.

After the formation of the porous polycrystalline silicon layer 4, the platinum electrode is used as a negative electrode and the n-type silicon substrate 1 is used as a positive electrode in a sulfuric acid solution at 25 ° C. to electrochemically oxidize at a constant current of 20 mA / cm ^2. did. Then, after washing with water and drying, auxiliary oxidation was performed by a rapid heating method. The conditions of rapid thermal oxidation by the rapid heating method are as follows.
L / min (300 sccm), oxidation temperature 750 ° C,
The oxidation time was 1 hour. After that, the film thickness of 1
A conductive thin film 7 of a 0 nm gold thin film was formed by an evaporation method.

The field emission type electron source 10 thus manufactured is introduced into a vacuum chamber (not shown),
As shown in FIG.
1 (radiation electron collecting electrode) is arranged, the degree of vacuum in the vacuum chamber is set to 5 × 10 ⁻⁵ Pa, and a DC voltage Vps is applied between the conductive thin film 7 (positive electrode) and the ohmic electrode 2 (negative electrode). FIG. 13 shows the results of measuring the diode current Ips and the emission electron current Ie by applying a DC voltage Vc of 100 V between the collector electrode 21 and the conductive thin film 7. Here, the horizontal axis in FIG.
The vertical axis indicates the current density, and the circle () in the figure indicates the diode current Ips, and the circle () in the figure indicates the emission electron current Ie.

As can be seen from FIG. 13, the DC voltage Vps
Was set to 20 V, an emission electron current Ie of 10 μA / cm ² was obtained. Therefore, the oxidation temperature (800 ° C. to 900 ° C.) when oxidizing only by rapid thermal oxidation by the rapid heating method is used.
C)), the electron emission current Ie having a large value despite performing only an oxidation treatment step (oxidation step using sulfuric acid at 25 ° C. and rapid thermal oxidation at 750 ° C.) at a relatively low temperature (750 ° C. or less). Is observed, it is possible to produce a desired electron source even using a substrate that requires a low-temperature process, such as a glass substrate that is inexpensive compared to a quartz glass substrate. The type, temperature and current density of the acid when oxidizing with an acid are not limited to the above conditions,
The conditions for rapid thermal oxidation are not limited to the above conditions.

(Embodiment 6) By the way, as already described, the strong electric field drift layer 6 in the embodiment 1 has at least a columnar polycrystalline silicon (grain) 51 and a polycrystalline silicon 51 as shown in FIG. A thin silicon oxide film 52 formed on the surface, a microcrystalline silicon layer 63 of nanometer order interposed between the polycrystalline silicon 51, and a crystal grain size of the microcrystalline silicon layer 63 formed on the surface of the microcrystalline silicon layer 63 It is considered to be composed of a silicon oxide film 64 which is an insulating film having a smaller thickness. That is, it is considered that the strong electric field drift layer 6 has a porous surface at each grain and maintains a crystalline state at the center of each grain. Therefore, the strong electric field drift portion 6
Is applied to the silicon oxide film 64, the injected electrons are accelerated by the strong electric field applied to the silicon oxide film 64, and the space between the polycrystalline silicons 51 is directed toward the surface between the polycrystalline silicons 51 as indicated by an arrow A in FIG. Since the drift occurs in the direction (upward in FIG. 5), the electron emission efficiency can be improved. Therefore, the present inventors focused on the silicon oxide film 64 in order to further increase the electron emission efficiency. In other words, when the surface of the microcrystalline silicon layer 63 is completely oxidized, the entire surface of the microcrystalline silicon layer 63 is covered with oxygen atoms 65 as shown in FIG. Therefore, when oxidized by the rapid thermal oxidation method described above, the surface of the microcrystalline silicon layer 63 may not be completely covered with the oxygen atoms 65 as shown in FIG.
Is the coverage of the microcrystalline silicon layer 63 due to the above insufficient?).

The basic structure and manufacturing method of the field emission type electron source of the present embodiment are substantially the same as those of the fifth embodiment. A strong electric field drift layer 6 made of a polycrystalline silicon layer is formed, and a conductive thin film 7 made of a metal thin film (for example, a gold thin film) is formed on the strong electric field drift layer 6. An ohmic electrode 2 is formed on the back surface of the n-type silicon substrate 1. In this embodiment, a single-crystal n-type silicon substrate 1 having a resistivity relatively close to that of a conductor (for example, having a resistivity of 0.1 Ωcm) is used as a conductive substrate.
(100) substrate).

Therefore, in the field emission type electron source 10 of the present embodiment, for example, as shown in FIG. 11, the conductive thin film 7 is disposed in a vacuum and the collector electrode 21 is opposed to the conductive thin film 7. A DC voltage Vps is applied as a positive electrode to the n-type silicon substrate 1 (ohmic electrode 2) using the conductive thin film 7 as a positive electrode.
Is applied to the conductive thin film 7 as a positive electrode and a DC voltage Vc is applied, whereby electrons injected from the n-type silicon substrate 1 serving as the conductive substrate drift in the strong electric field drift portion 6 and are emitted through the conductive thin film 7. . Therefore, as the conductive thin film 7, it is desirable to use a material having a small work function (for example, gold, aluminum, chromium, tungsten, nickel, platinum, or the like). In the present embodiment, the conductive thin film 7 is made of a gold thin film, but may be made of at least two thin film layers stacked in the thickness direction. In the case of a two-layer thin film layer, for example, gold or the like is used as the material of the upper thin film layer, and chromium, nickel, or the like is used as the material of the lower thin film layer (the thin film electrode layer on the strong electric field drift portion 6 side). , Platinum, titanium, iridium and the like may be employed.

Hereinafter, the manufacturing method will be described. Since the manufacturing method of this embodiment is substantially the same as that of the fourth and fifth embodiments, the description will be made with reference to FIG.

First, after forming an ohmic electrode 2 on the back surface of the n-type silicon substrate 1, a non-doped polycrystalline silicon layer 3 having a predetermined thickness (for example, 1.5 μm) is formed on the main surface of the n-type silicon substrate 1. For example, a structure as shown in FIG. 10A is obtained by forming (depositing) by the LPCVD method. The method of forming the polycrystalline silicon layer 3 is the same as in the fourth and fifth embodiments.

After the non-doped polycrystalline silicon layer 3 is formed, an anodizing tank containing an electrolytic solution comprising a mixture of a 55 wt% aqueous solution of hydrogen fluoride and ethanol in a ratio of about 1: 1 is used. A platinum electrode (not shown) is connected to the negative electrode, n
Type silicon substrate 1 (ohmic electrode 2) as a positive electrode
By performing anodic oxidation treatment under predetermined conditions while irradiating the polycrystalline silicon layer 3 with light, a porous polycrystalline silicon layer 4 as a porous layer is formed, and a structure as shown in FIG. 10B is obtained. . Here, in the present embodiment, the surface of the polycrystalline silicon layer 3 is irradiated with light by a 500 W tungsten lamp during the anodic oxidation process while maintaining a constant current density as a condition of the anodizing process. Although the whole is made porous, the polycrystalline silicon layer 3
May be made porous.

Next, a strong electric field drift layer 6 is formed by oxidizing the porous polycrystalline silicon layer 4 as the porous layer, and the structure shown in FIG. 10C is obtained. Here, in oxidizing the porous polycrystalline silicon layer 4, the porous polycrystalline silicon layer 4 is oxidized by irradiating ultraviolet light in a gas atmosphere containing at least one of oxygen (O ₂ ) and ozone (O ₃ ). (Main oxidation process). In addition, as a light source of the ultraviolet light, an ultraviolet lamp (for example, when the main wavelength component is 1).
An 85 nm or 256 nm low pressure mercury lamp) or an excimer laser having a main wavelength component of 172 nm may be used.
The irradiation time of the ultraviolet light may be appropriately set between several minutes and several hours.

After the strong electric field drift layer 6 is formed, a conductive thin film 7 is formed on the strong electric field drift layer 6 by, for example, a vapor deposition method, so that the field emission type electron source 10 having the structure shown in FIG. Is obtained. In the present embodiment,
Although the conductive thin film 7 is formed by an evaporation method, the method of forming the conductive thin film 7 is not limited to the evaporation method, and for example, a sputtering method may be used.

By the way, the aforementioned Japanese Patent Application No. Hei 10-27234 is disclosed.
0, Japanese Patent Application No. 10-272342, Japanese Patent Application No. 10-27
In the manufacturing method proposed in No. 1876, the strong electric field drift layer 6 is formed by oxidizing the porous polycrystalline silicon layer 4 by a rapid heating method, and the oxidation temperature at this time is relatively high (800 ° C. to 900 ° C.). ° C), so it is inevitable to use a conductive film formed on expensive quartz glass as a conductive substrate or a single-crystal silicon substrate. There was a problem that it was difficult to achieve.

On the other hand, according to the method of manufacturing the field emission type electron source of the present embodiment, when oxidizing the porous polycrystalline silicon layer 4, the ultraviolet light is irradiated in a gas atmosphere containing at least one of oxygen and ozone. Is irradiated to oxidize the porous polycrystalline silicon layer 4, which makes it possible to reduce the number of electrons compared to the conventional case where the porous polycrystalline silicon layer 4 is oxidized by a rapid heating method to form a strong electric field drift layer. Emission efficiency (hereinafter, referred to as electron emission efficiency) is increased. The electron emission efficiency is a value obtained by (Ie / Ips) × 100 from the above-described diode current Ips and emission electron current Ie. The reason why the electron emission efficiency is increased as described above is that, for example, when ultraviolet light is irradiated in an ozone atmosphere, ultraviolet light (UV
15), the silicon bond on the outermost surface of the microcrystalline silicon layer 63 shown in FIG.
An i-O bond is formed, and the coverage of the surface of the microcrystalline silicon layer 63 with the oxygen atoms 65 is improved (that is, FIG.
(Approaching the ideal state as shown in FIG. 4). It is needless to say that the decomposition of the gas is promoted by the irradiation of the ultraviolet light.

Thus, according to the manufacturing method of the present embodiment, when the porous polycrystalline silicon layer 4 is oxidized,
By irradiating the porous polycrystalline silicon layer 4 with ultraviolet light in a gas atmosphere containing at least one of oxygen and ozone, the electron emission efficiency can be increased. Further, since the strong electric field drift portion 6 can be formed by oxidizing the porous polycrystalline silicon layer 4 without performing heating, the porous polycrystalline silicon layer 4 is oxidized by the rapid heating method as in the related art, and the strong electric field drift portion 6 is formed. The strong electric field drift portion 6 can be formed at a lower temperature than when the electric field drift portion is formed (in this case, heating to 800 ° C. to 900 ° C.). The restrictions on the substrate are reduced, and the area and cost can be easily reduced.

(Embodiment 7) The method of manufacturing the field emission electron source of this embodiment is substantially the same as that of Embodiment 6, except that the step of oxidizing the porous polycrystalline silicon layer 4 as the porous layer is different. Only the other steps are the same, and the description of the same steps is omitted.

In this embodiment, when oxidizing the porous polycrystalline silicon layer 4 as a porous layer, the porous polycrystalline silicon layer 4 is exposed to plasma in a gas atmosphere containing at least one of oxygen and ozone. Oxidizes (main oxidation process). Here, a high frequency of, for example, 13.56 MHz may be used to generate plasma. 1
It is desirable that the RF power in the case of using a high frequency of 3.56 MHz be appropriately set in a range of several tens of watts to several hundreds of watts, for example. In addition, the processing time for exposing to plasma may be appropriately set between several minutes and several hours. The plasma may be generated by causing a discharge in the gas atmosphere, or the plasma may be generated by another gas (for example, an inert gas) without performing the discharge in the gas atmosphere.

Thus, according to the manufacturing method of this embodiment, when oxidizing the porous polycrystalline silicon layer 4,
By oxidizing the porous polycrystalline silicon layer 4 by exposing it to plasma in a gas atmosphere containing at least one of oxygen and ozone, the porous polycrystalline silicon layer 4 is oxidized by a rapid heating method as in the prior art. The electron emission efficiency can be increased as compared with the case where the strong electric field drift layer 6 is formed. Further, by oxidizing the porous polycrystalline silicon layer 4 without performing heating, the strong electric field drift layer 6 is formed.
In the case where the porous polycrystalline silicon layer 4 is oxidized by the rapid heating method to form a strong electric field drift portion (in this case, it is necessary to heat to 800 ° C. to 900 ° C.). In comparison, the strong electric field drift layer 6 can be formed at a lower temperature, the process temperature is lower, the restriction on the conductive substrate is reduced, and the area and cost can be easily reduced.

(Embodiment 8) The method of manufacturing a field emission electron source of this embodiment is substantially the same as that of Embodiment 6, except that the step of oxidizing the porous polycrystalline silicon layer 4 as the porous layer is different. Only the other steps are the same, and the description of the same steps is omitted.

In the present embodiment, when oxidizing the porous polycrystalline silicon layer 4 as the porous layer, the porous polycrystalline silicon layer is oxidized by heating in a gas atmosphere containing at least ozone (main oxidation treatment). process). Here, the heating temperature may be set to 100 ° C. to 600 ° C., and the heating time may be appropriately set to several minutes to several hours. In addition,
The heating temperature may be higher than 600 ° C., but the restriction on the conductive substrate is reduced (a conductive film is formed on a glass substrate that is less expensive than an expensive quartz glass substrate). From this point, 100 ℃ ~ 60
It is desirable to set appropriately between 0 ° C.

Thus, according to the manufacturing method of this embodiment, when the porous polycrystalline silicon layer 4 is oxidized,
Since the porous polycrystalline silicon layer 4 is oxidized by heating in a gas atmosphere containing at least ozone to form the strong electric field drift layer 6, the porous layer is oxidized by a rapid heating method as in the related art. The electron emission efficiency can be increased as compared with the case where the strong electric field drift layer 6 is formed. Further, the temperature is lower than in the conventional case where the porous polycrystalline silicon layer is oxidized by the rapid heating method to form the strong electric field drift layer 6 (in this case, heating to 800 to 900 ° C.). Thus, the strong electric field drift layer 6 can be formed, the process temperature is lowered, the restriction on the conductive substrate is reduced, and the area and cost can be easily reduced.

(Embodiment 9) The method of manufacturing a field emission electron source of this embodiment is substantially the same as that of Embodiment 6, except that the step of oxidizing the porous polycrystalline silicon layer 4 as the porous layer is different. Only the other steps are the same, and the description of the same steps is omitted.

In the present embodiment, in oxidizing the porous polycrystalline silicon layer 4 as a porous layer, the porous polycrystalline silicon layer 4 is oxidized by irradiating ultraviolet light and heating (the main oxidation treatment step). ). Here, the heating temperature may be set to 100 ° C. to 600 ° C., and the heating time may be appropriately set to several minutes to several hours. The heating temperature is 600 ° C.
Although a higher temperature may be used, the restriction of the conductive substrate is reduced (from the viewpoint of using a substrate in which a conductive film or the like is formed on an inexpensive glass substrate as compared with an expensive quartz glass substrate, as the conductive substrate), It is desirable to set appropriately between 100 ° C and 600 ° C.

Thus, according to the manufacturing method of the present embodiment, when the porous polycrystalline silicon layer 4 is oxidized,
Since the porous polycrystalline silicon layer 4 is oxidized to form the strong electric field drift layer 6 by irradiating ultraviolet light and heating, the porous polycrystalline silicon layer is oxidized by a rapid heating method as in the prior art. Thus, the electron emission efficiency can be increased as compared with the case where the strong electric field drift layer 6 is formed. Further, the strong electric field drift layer 6 can be formed at a lower temperature than in the case where the strong electric field drift layer 6 is formed by oxidizing the porous layer by the rapid heating method as in the related art, and the process temperature becomes lower. The restriction on the conductive substrate is reduced, and the area and cost can be easily reduced.

(Embodiment 10) The method of manufacturing a field emission electron source of this embodiment is substantially the same as that of Embodiment 6, except that the step of oxidizing the porous polycrystalline silicon layer 4 as the porous layer is different. Only the other steps are the same, and the description of the same steps is omitted.

In the present embodiment, when oxidizing the porous polycrystalline silicon layer 4 as the porous layer, the porous polycrystalline silicon layer 4 is irradiated with ultraviolet light and heated in a gas atmosphere containing at least one of oxygen and ozone. The crystalline silicon layer 4 is oxidized (main oxidation process). Here, the heating temperature may be set to 100 ° C. to 600 ° C., and the heating time may be appropriately set to several minutes to several hours. The heating temperature is 6
Although the temperature may be higher than 00 ° C., the restriction on the conductive substrate is reduced (from the viewpoint of using a substrate having a conductive film formed on a cheap glass substrate as compared with an expensive quartz glass substrate). Is desirably set appropriately between 100 ° C. and 600 ° C.

Thus, according to the manufacturing method of this embodiment, when oxidizing the porous polycrystalline silicon layer 4,
Since the porous polycrystalline silicon layer 4 is oxidized by irradiating ultraviolet light and heating in a gas atmosphere containing at least one of oxygen and ozone to form the strong electric field drift layer 6, a conventional method is employed. The porous polycrystalline silicon layer is oxidized by a rapid heating method to form a strong electric field drift layer 6.
It is possible to increase the electron emission efficiency as compared with the case of forming. Further, the strong electric field drift layer 6 can be formed at a lower temperature than in the case where the strong electric field drift layer 6 is formed by oxidizing the porous layer by the rapid heating method as in the related art.
As the process temperature becomes lower, the restriction on the conductive substrate is reduced, and it is easy to increase the area and reduce the cost.

(Embodiment 11) The manufacturing method of the field emission type electron source of this embodiment is substantially the same as any one of Embodiments 6 to 10, and is different from that before the main oxidation process in each embodiment. At least one of the following
The present invention is characterized in that an auxiliary oxidation process for oxidizing the porous polycrystalline silicon layer 4 by a rapid heating method is provided.
The conditions of the auxiliary oxidation treatment process by the rapid heating method include, for example, using a lamp annealing apparatus, in dry oxygen, at an oxidation temperature of 600 ° C. to 900 ° C. and an oxidation time of 30 minutes to 30 minutes.
It may be 120 minutes.

However, according to the manufacturing method of the present embodiment, it is possible to compensate for the lack of oxidation in the oxidation treatment by the conventional rapid heating method, and to further increase the electron emission efficiency.

(Embodiment 12) The manufacturing method of the field emission type electron source of this embodiment is substantially the same as any one of Embodiments 6 to 10, and is different from that before the main oxidation process in each embodiment. At least one of the following
The present invention is characterized in that an auxiliary oxidation process for oxidizing the porous polycrystalline silicon layer 4 with an acid is provided. That is, as the manufacturing method of the present embodiment, for example, “auxiliary oxidation treatment step with acid → main oxidation treatment step”, “main oxidation treatment step → auxiliary oxidation treatment step with acid” "Auxiliary oxidation process by acid → Main oxidation process → Auxiliary oxidation process by thermal oxidation method (eg, rapid heating method)", “Auxiliary oxidation process by acid → Assistance by thermal oxidation method (eg, rapid heating method)” Oxidation process → main oxidation process ”,“ main oxidation process → thermal oxidation method (for example,
Auxiliary oxidation process by rapid heating method → Auxiliary oxidation process by acid ”,“ Auxiliary oxidation process by thermal oxidation method (for example, rapid heating method) → Main oxidation process → Auxiliary oxidation process by acid ”,“ Heat Auxiliary oxidation process by oxidation method (for example, rapid heating method) → Auxiliary oxidation process with acid → Main oxidation process ”,“ Main oxidation process → Auxiliary oxidation process with acid → Thermal oxidation method (for example, rapid heating method) Auxiliary oxidation process by thermal oxidation method (eg, rapid heating method) → Auxiliary oxidation process by thermal oxidation method (eg, rapid heating method), “Auxiliary oxidation process by thermal oxidation method (eg, rapid heating method)” The strong electric field drift layer 6 may be formed by performing a process such as “process”.

Here, the condition of the auxiliary oxidation treatment process with an acid is to use a treatment tank containing an acid (eg, HNO ₃ , H ₂ SO ₄ , aqua regia, etc.).
The treatment tank used for the anodic oxidation treatment described in the first embodiment may be used), a platinum electrode (not shown) as a negative electrode, and an n-type silicon substrate 1 (ohmic electrode 2) as a conductive substrate as a positive electrode. What is necessary is just to flow a predetermined electric current.

For example, when the porous polycrystalline silicon layer 4 is oxidized with, for example, dilute nitric acid (for example, 10% dilute nitric acid) before the main oxidation process, the holes are defined as h ⁺ and the electrons are defined as e ⁻ . It is considered that the following reaction has occurred. Negative electrode side: HNO ₃ + 3H ⁺ → NO + 2H ₂ O + 3h ⁺ Positive electrode side: 3h ⁺ + Si + 2H ₂ O → SiO ₂ + 4H ⁺ + e ^- Also, before the main oxidation process, the porous polycrystalline silicon layer 4 is formed.
Is oxidized with diluted sulfuric acid (for example, 10% diluted sulfuric acid), the following reaction is considered to have occurred. Negative electrode side: H ₂ SO ₄ + 2H ⁺ → SO ₂ + 2H ₂ O + 2h ⁺ Positive electrode side: 2h ⁺ + Si + 2H ₂ O → SiO ₂ + 4H ⁺ + 2e
^- Thus, according to the manufacturing method of this embodiment, it is possible to compensate for the oxidation lack of oxidation treatment with conventional rapid heating methods, it is possible to further improve the electron emission efficiency.

(Embodiment 13) In the manufacturing methods of Embodiments 6 to 10, since a mixed solution of an aqueous solution of hydrogen fluoride and ethanol is used as an electrolytic solution in the anodic oxidation treatment, silicon atoms are reduced. It will be terminated by a hydrogen atom. For this reason, the hydrogen content in the strong electric field drift layer 6 is relatively large, the withstand voltage is reduced, and the distribution of hydrogen in the strong electric field drift layer 6 changes with time, so that the electron emission efficiency with time stability May be worse.

On the other hand, the manufacturing method of the field emission type electron source according to the present embodiment is substantially the same as any one of the sixth to tenth embodiments. Is characterized in that a pre-oxidation step of oxidizing the porous polycrystalline silicon layer 4 with an oxidizing solution is provided before the step (b). That is, in the manufacturing method of the present embodiment, the strong electric field drift layer 6 is formed by oxidizing the extreme surface of the porous polycrystalline silicon layer 4 with an oxidizing solution and then performing a main oxidation process. in short,
In this embodiment, the hydrogen atoms of the porous polycrystalline silicon layer 4 terminates the porous polycrystalline silicon atoms of the silicon layer 4 at the time of forming the anodic oxidation treatment, was replaced by an oxygen atom by oxidation solvent solution ing.

Here, as the oxidizing solution, it is desirable to use one or more oxidizing agents selected from the group consisting of nitric acid, sulfuric acid, hydrochloric acid and aqueous hydrogen peroxide.

[0138] Thus, according to the manufacturing method of this embodiment, the porous polycrystalline extreme surface layer of the silicon layer 4 formed by the anodic oxidation treatment after the oxidation by oxidizing solvent solution, which primarily oxidation process Therefore, the amount of hydrogen contained in the strong electric field drift layer 6 can be reduced, and a field emission type electron source having a high withstand voltage with little change in electron emission efficiency with time can be realized.

In the manufacturing method according to each of Embodiments 11 and 12, the pre-oxidation process in which the porous polycrystalline silicon layer 4 is oxidized with the oxidizing solution before the main oxidation process and the auxiliary oxidation process is performed. It may be provided. Further, by heating the oxidizing solution, the oxidation rate is increased, so that the treatment time with the oxidizing solution can be shortened.

A field emission electron source was manufactured under the following conditions in the manufacturing method of the present embodiment.

As the n-type silicon substrate 1, a (100) substrate having a resistivity of 0.1 Ωcm and a thickness of 525 μm was used. The polycrystalline silicon layer 3 (see FIG. 10A) is formed by an LPCVD method.
0 Pa, the substrate temperature was 640 ° C., and the flow rate of the monosilane gas was 0.6 L / min (600 sccm) in a standard state.

In the anodic oxidation treatment for making the polycrystalline silicon layer 3 porous, an electrolytic solution obtained by mixing a 55 wt% aqueous solution of hydrogen fluoride and ethanol at a ratio of about 1: 1 is used as the electrolytic solution. Touch the surface to the electrolyte,
A predetermined current was passed using the platinum electrode immersed in the electrolyte as a negative electrode and the n-type silicon substrate 1 (ohmic electrode 2) as a positive electrode. Here, the current density during the anodization period is 30 mA.
/ Cm ² , and the anodic oxidation time was 10 seconds.

In the pre-oxidation process, an oxidizing solution composed of a mixture of sulfuric acid and hydrogen peroxide was used as the oxidizing solution, and the sample on which the porous polycrystalline silicon layer 4 was formed was added to the oxidizing solution for 30 minutes. Soaked for minutes.

After the pre-oxidation process, an auxiliary oxidation process was performed. The auxiliary oxidation process is performed in a 1 mol% by weight sulfuric acid solution using a platinum electrode as a negative electrode and an n-type silicon substrate 1 (ohmic electrode 2) as a conductive substrate as a positive electrode at 20 mA / c.
It was electrochemically oxidized at a constant current of m ² .

Thereafter, after washing with water and further drying, a main oxidation treatment step was performed. In the main oxidation process, ultraviolet rays having main wavelengths of 185 nm and 254 nm were irradiated on the main surface side in a gas atmosphere containing ozone and oxygen while heating the substrate temperature to 500 ° C. The oxidation time in the main oxidation process was 1 hour.

The conductive thin film 7 was formed by patterning a gold thin film deposited on the entire surface of the strong electric field drift portion 6 by a vapor deposition method using a photolithography technique, an etching technique, or the like. The thickness of the conductive thin film 7 was 10 nm.

The field emission type electron source manufactured under the above conditions was introduced into a vacuum chamber (not shown),
The collector electrode 21 (radiated electron collecting electrode) is arranged at a position facing the conductive thin film 7 as shown in FIG. 3, the degree of vacuum in the vacuum chamber is set to 5 × 10 ⁻⁵ Pa, and the collector electrode 21 and the conductive thin film 7 are A DC voltage Vc of 100 V is applied between the conductive thin film 7 (positive electrode) and the ohmic electrode 2 (negative electrode).
And the diode current Ips flowing between the conductive thin film 7 and the ohmic electrode 2 and the conductive thin film 7 from the field emission type electron source 10 '.
The emission electron current Ie flowing between the collector electrode 21 and the conductive thin film 7 due to the electrons e ⁻ emitted through the electrode was measured. As a result, the emission electron current Ie was 10 μA / c
A good emission electron current of m ² was obtained.

(Embodiment 14) FIG. 16 shows an example of a display using a field emission electron source 10 having substantially the same configuration as that of Embodiment 6. Note that the field emission electron source 10 of the present embodiment is different from the field emission electron source 10 of the first embodiment in that the conductive thin film 7 is formed in a stripe shape.

The display shown in FIG. 16 includes a glass substrate 33 arranged to face the conductive thin film 7 of the field emission type electron source 10, and a stripe-shaped surface of the glass substrate 33 facing the field emission type electron source 10. A collector layer 31 that emits visible light by an electron beam emitted from the conductive thin film 7 is formed so as to cover the collector electrode 31. The space between the field emission electron source 10 and the glass substrate 33 is evacuated.

In this display, the conductive thin film 7 is formed in a stripe shape, and the collector electrode 31 is formed in a stripe shape in a direction perpendicular to the conductive thin film 7, and the collector electrode 31 and the conductive thin film 7 are appropriately formed. By selectively applying a voltage (electric field), electrons are emitted only from the conductive thin film 7 to which the voltage is applied. As for the emitted electrons, only the electrons emitted from the region where the voltage is applied to the opposing collector electrode 31 in the conductive thin film 7 from which the electrons have been emitted are accelerated, and the phosphor covering the collector electrode 31 is accelerated. Flash.

In short, in the display having the configuration shown in FIG. 16, a specific conductive thin film 7 and a specific collector electrode 31 are provided.
By applying a voltage to the phosphor layer 32, a portion of the phosphor layer 32 corresponding to a region where the conductive thin film 7 to which the voltage is applied and the collector electrode 31 intersect can be illuminated.
Then, by appropriately switching the conductive thin film 7 to which a voltage is applied and the collector electrode 31, it is possible to display images, characters, and the like.

The method of manufacturing the field emission type electron source 10 of the present embodiment is substantially the same as that of the sixth embodiment, and after forming the conductive thin film 7 patterned in a predetermined shape (a stripe shape in the present embodiment). A process of irradiating ultraviolet light in a gas atmosphere containing at least one of oxygen and ozone as described in the sixth embodiment, and a plasma in a gas atmosphere containing at least one of oxygen and ozone as described in the seventh embodiment. Ninth Embodiment, Heating in a gas atmosphere containing at least ozone as described in the eighth embodiment, Ninth Embodiment
At least one of the processing of irradiating ultraviolet light and heating as described in the above, and the processing of irradiating ultraviolet light and heating in a gas atmosphere containing at least one of oxygen and ozone as described in Embodiment 10 There is a feature in performing processing. Thus, according to the manufacturing method of the present embodiment, by performing the treatment, in addition to oxidizing the porous polycrystalline silicon layer 4, it is possible to remove contamination due to organic substances in a process before the treatment. Release efficiency increases.

In order to form the conductive thin film 7 in a stripe shape, for example, a conductive thin film 7 is formed on the entire surface of the strong electric field drift layer 6 and then a photoresist layer is formed on the conductive thin film 7 by coating. Then, after patterning the photoresist layer by a photolithography technique,
The conductive thin film 7 may be etched using the photoresist layer as a mask to remove the photoresist layer. Alternatively, the conductive thin film 7 in a stripe shape may be formed on the strong electric field drift layer 6 by an evaporation method or the like using a metal mask having a stripe-shaped opening pattern.

FIG. 17 is a schematic sectional view of a display provided with a field emission type electron source 10 'using a substrate having a conductive film 12 formed on one surface of an insulating substrate 11 made of a glass substrate as a conductive substrate. Is shown.

The display shown in FIG. 17 includes a glass substrate 33 arranged opposite to the conductive thin film 7 of the field emission type electron source 10 ′.
The collector electrode 31 is striped on the surface facing 0 '.
Is formed, and a phosphor layer 32 that emits visible light by an electron beam emitted from the conductive thin film 7 is formed on the collector electrode 31 on the side facing the field emission electron source 10 ′ (here, Each phosphor layer 32 in FIG. 17 constitutes a pixel). The space between the field emission electron source 10 'and the glass substrate 33 is evacuated. FIG.
In the display shown in FIG. 2, the insulating substrate 11 constitutes a rear plate, the glass substrate 33 constitutes a face plate, and a supporting spacer 40 is interposed between the opposing plates 11 and 33 so as to form both plates. 11,33
It is configured to keep the space between them at a vacuum. In short, an airtight space is formed between the plates 11 and 33. A reinforcing spacer 41 is interposed between the field emission electron source 10 ′ and the face plate 33.

In the display shown in FIG. 17, the conductive thin film 7 is formed in a stripe shape, and the conductive film 12 is formed in a stripe shape in a direction orthogonal to the conductive thin film 7. By appropriately selecting the conductive film 12 and applying a voltage (electric field), electrons are emitted only from the conductive thin film 7 to which the voltage is applied, and the opposing phosphor layer 32 emits light. Therefore, images and characters can be displayed by appropriately switching the conductive thin film 7 and the conductive film 12 to which a voltage is applied.

Incidentally, the field emission type electron source 1 shown in FIG.
The manufacturing method of 0 ′ is substantially the same as that of the sixth embodiment. After forming the conductive thin film 7 patterned in a predetermined shape (a stripe shape in the present embodiment), oxygen A process of irradiating ultraviolet light in a gas atmosphere containing at least one of ozone, a process of exposing to plasma in a gas atmosphere containing at least one of oxygen and ozone as described in Embodiment 7, and a process as described in Embodiment 8. A process of performing heating in a gas atmosphere containing at least ozone,
The process of irradiating ultraviolet light and heating as described in Embodiment 9 and the process of irradiating ultraviolet light and heating in a gas atmosphere containing at least one of oxygen and ozone as described in Embodiment 10 It is characterized in that at least one process is performed. Thus, according to the manufacturing method of the present embodiment, by performing the treatment, in addition to oxidizing the porous polycrystalline silicon layer 4, it is possible to remove contamination due to organic substances in a process before the treatment. Release efficiency increases.

A field emission electron source was manufactured as an example employing the following conditions in the manufacturing method of the present embodiment.

As the n-type silicon substrate 1, a (100) substrate having a resistivity of 0.1 Ωcm and a thickness of 525 μm was used. The polycrystalline silicon layer 3 (refer to FIG. 1A) is formed by an LPCVD method.
0 Pa, the substrate temperature was 640 ° C., and the flow rate of the monosilane gas was 0.6 L / min (600 sccm) in a standard state.

In the anodic oxidation treatment for making the polycrystalline silicon layer 3 porous, an electrolytic solution obtained by mixing a 55 wt% aqueous solution of hydrogen fluoride and ethanol at a ratio of about 1: 1 is used as the electrolytic solution. Touch the surface to the electrolyte,
A predetermined current was passed using the platinum electrode immersed in the electrolyte as a negative electrode and the n-type silicon substrate 1 (ohmic electrode 2) as a positive electrode. Here, the current density during the anodization period is 30 mA.
/ Cm ² , and the anodic oxidation time was 10 seconds.

The conditions for rapid thermal oxidation of the porous polysilicon layer 4 are such that the flow rate of oxygen gas is 0.3 L / min under standard conditions.
(300 sccm), the oxidation temperature was 900 ° C., and the oxidation time was 1 hour.

The conductive thin film 7 was formed by patterning a gold thin film deposited on the entire surface of the strong electric field drift portion 6 by a vapor deposition method using a photolithography technique, an etching technique, or the like. The thickness of the conductive thin film 7 was 10 nm.

Processing after forming the conductive thin film 7 (hereinafter referred to as
As post-treatment, oxygen (O _Two) And ozone (O_Three)
Of UV light in a mixed gas (2000 ppm) atmosphere
Was done. 110W low-pressure mercury lamp as an ultraviolet light source
Using a pump, the heating temperature was 200 ° C and the processing time was 30 minutes.
did. The post-treatment is an oxidation treatment step.

Also, as Comparative Example 1, a field emission type electron source without the above-mentioned post-processing was manufactured, and as Comparative Example 2, a conductive thin film 7 was formed using a metal mask, and the above-mentioned field emission without the above-mentioned post-processing was performed. Type electron source was manufactured. Note that the difference between this embodiment and Comparative Example 1 is only the presence or absence of the post-processing.
The difference between the present embodiment and Comparative Example 2 is that in the present embodiment, the conductive thin film 7 is patterned by using a photolithography technique or the like, and then the above-mentioned post-processing is performed. Is that the conductive thin film 7 is patterned at the time of film formation using a metal mask, and the above-mentioned post-processing is not performed thereafter.

The field emission type electron source 10 of this embodiment is
Introduced into the chamber (not shown) and shown in FIG.
The collector electrode 21 at a position facing the conductive thin film 7
(Radiation electron collecting electrode)
Degree 5 × 10^-FivePa, the collector electrode 21 and the conductivity
A DC voltage Vc of 100 V is applied between the thin film 7 and
Between the conductive thin film 7 (positive electrode) and the ohmic electrode 2 (negative electrode)
By changing the applied DC voltage Vps variously, the conductive thin film 7
Diode current Ips flowing between the resistor and ohmic electrode 2
From the field emission type electron source 10 through the conductive thin film 7.
Electron e ^-The collector electrode 21 and the conductive thin film
7 was measured. That
The results are shown in FIG.

In FIG. 18, the horizontal axis represents the value of the DC voltage Vps, the left vertical axis represents the current densities of the diode current Ips and the emission electron current Ie, and the right vertical axis represents the electron emission efficiency (Ie / Ip).
s × 100). Also, the solid line (同) in the figure indicates the diode current Ips of the present embodiment, and the one-dot chain line (■)
Indicates the emission electron current Ie of this example, and the broken line (■) indicates the electron emission efficiency of this embodiment. Similarly, the solid line (□) in the figure indicates the diode current Ips of Comparative Example 1.
And the dashed line (□) indicates the emission electron current Ie of Comparative Example 1.
, And the broken line (□) indicates the electron emission efficiency of Comparative Example 1. In the same figure, the solid line (線) represents the diode current Ips of Comparative Example 2, the dashed line (○) represents the emission electron current Ie of Comparative Example 2, and the broken line (○) represents the electron emission efficiency of Comparative Example 2. Are respectively shown.

In FIG. 18, first, Comparative Example 1 and Comparative Example 2
Compared with the above, the current density of the diode current Ips is substantially the same (see,), whereas the current density of the emission electron current Ie is smaller in Comparative Example 1 than in Comparative Example 2 (see,). You can see that. Therefore, the electron emission efficiency of Comparative Example 1 is smaller than that of Comparative Example 2 (see,). This result indicates that in Comparative Example 1, the contamination of the organic matter due to the residual resist of the photoresist layer used for patterning the conductive thin film 7 remains, whereas in Comparative Example 2, the metal mask was used for patterning the conductive thin film 7. It is presumed that this is due to the fact that organic materials are less contaminated by using.

Next, when this embodiment is compared with Comparative Example 1, the emission electron current Ie of this embodiment is greater than that of Comparative Example 1.
, The current density of the diode current Ips is smaller in this example than in Comparative Example 1 (see), and the current density of this embodiment is smaller than that of Comparative Example 1. The electron emission efficiency is higher than that of (see,). For example, when the DC voltage Vps is 20 V, in the present embodiment, the current density of the emission electron current Ie is approximately 30 times that of Comparative Example 1, the current density of the diode current Ips is approximately 1/4 of that of Comparative Example 1, The release efficiency is about 12 of Comparative Example 1.
It is 0 times. That is, in this embodiment, the electron emission efficiency is much higher than in Comparative Example 1. further,
Even when the present embodiment is compared with the comparative example 2, the present embodiment has a higher current density of the emission electron current Ie, and the present embodiment has a higher electron emission efficiency than the comparative example 2. Has become. Here, the reason why the current density of the emission electron current Ie is higher in the present example than in the comparative example 2 is because the effect of cleaning the surface of the field emission type electron source 10 ′ by the above-described post-processing or strong effect. It is supposed that one or both effects of improving the film quality (improving the coverage by oxygen atoms) of the silicon oxide film 64 (see FIG. 5) on the surface of the microcrystalline silicon layer 63 constituting the electric field drift layer 6.

[0169]

According to a first aspect of the present invention, there is provided a conductive substrate, a strong electric field drift layer formed on one surface side of the conductive substrate, and a conductive thin film formed on the strong electric field drift layer. ,
A field emission type electron source in which electrons injected from the conductive substrate are drifted through the strong electric field drift layer and emitted through the conductive thin film by applying a voltage with the conductive thin film as a positive electrode with respect to the conductive substrate, The strong electric field drift layer is formed by a process including an oxidation step of electrochemically oxidizing the porous semiconductor layer in an electrolyte solution,
The porous semiconductor layer is oxidized by a process including an oxidation step of electrochemically oxidizing the porous semiconductor layer in an electrolyte solution to form a strong electric field drift layer. As compared with the case of forming the drift layer, the process temperature is lower, the restrictions on the material of the conductive substrate are reduced, and there is an effect that the area and the cost can be easily reduced. The invention according to claim 2 includes a conductive substrate, a strong electric field drift layer formed on one surface side of the conductive substrate, and a conductive thin film formed on the strong electric field drift layer. A field emission type electron source in which electrons injected from the conductive substrate drift through the strong electric field drift layer and are emitted through the conductive thin film when a voltage is applied as a positive electrode to the conductive substrate. is formed by a process comprising oxidation step of oxidizing the porous polycrystalline silicon layer is a porous semiconductor layer at a ratio <br/> comparatively low temperatures, even without low, it is formed on the first surface side of the conductive substrate Columnar polycrystalline silicon, a microcrystalline silicon layer comprising a nanostructure interposed between the polycrystalline silicon, and silicon formed on the surface of the microcrystalline silicon layer and having a thickness smaller than the crystal grain size of the microcrystalline silicon layer. Oxide film And it made of, so to form a strong electric field drift layer is oxidized by a process comprising oxidation step of oxidizing the porous semiconductor layer porous polycrystalline silicon layer is <br/> at relatively low temperatures, porous Process temperature is lower than in the case of forming a strong electric field drift layer by oxidizing a high-quality semiconductor layer only by a rapid heating method, and there are fewer restrictions on the material of the conductive substrate, resulting in a larger area and lower cost. In addition, the strong electric field drift layer has at least a columnar polycrystalline silicon formed on the one surface side of the conductive substrate and a microcrystal comprising a nanostructure interposed between the polycrystalline silicon. Since the silicon layer and the silicon oxide film formed on the surface of the microcrystalline silicon layer and having a thickness smaller than the crystal grain size of the microcrystalline silicon layer, the dependence of electron emission characteristics on the degree of vacuum is small. One during electron emission popping phenomenon there is an effect that it is possible to release the stable electron does not occur.

The invention of claim 7 is the invention of claims 1 to
In the invention of the fifth aspect , since the porous semiconductor layer is made of porous polycrystalline silicon, the electron emission characteristics have a small dependence on the degree of vacuum, and a popping phenomenon does not occur at the time of electron emission, and electrons are stably emitted with high efficiency. There is an effect that can be.

According to the invention of claim 8, a strong electric field drift layer comprising a conductive substrate, an oxidized porous semiconductor layer formed on one surface side of the conductive substrate, and a strong electric field drift layer formed on the strong electric field drift layer An electric field emission, wherein electrons injected from the conductive substrate are drifted through the strong electric field drift layer and emitted through the conductive thin film by applying a voltage with the conductive thin film as a positive electrode with respect to the conductive substrate. A method of manufacturing a porous electron source, comprising: oxidizing the porous semiconductor layer at a relatively low temperature when oxidizing the porous semiconductor layer, wherein the main oxidation processing step comprises: Since the layer is electrochemically oxidized in the electrolyte solution, the process temperature can be reduced compared to the case where the porous semiconductor layer is oxidized by a rapid heating method to form a strong electric field drift layer, and the conductivity is reduced. Constraint plate material is reduced, there is an effect that it is possible to provide a field emission electron source that can have a large area and low cost. The invention according to claim 9 is a conductive substrate, and a strong electric field drift layer formed of an oxidized porous semiconductor layer formed on one surface side of the conductive substrate;
A conductive thin film formed on the strong electric field drift layer, wherein the oxidized porous semiconductor layer is a strong electric field drift layer.
But at least a polycrystalline silicon columnar formed on the first surface side of the conductive substrate, and a microcrystalline silicon layer of nanostructures interposed between the polycrystalline silicon, the formed on the surface of the microcrystalline silicon layer It consists of a silicon oxide film with a thickness smaller than the crystal grain size of the microcrystalline silicon layer. When a voltage is applied to the conductive thin film as a positive electrode against the conductive substrate, electrons injected from the conductive substrate become strong electric fields. A method for manufacturing a field emission type electron source that drifts a drift layer and is emitted through a conductive thin film, wherein the porous semiconductor layer is oxidized by a main oxidation process of oxidizing the porous semiconductor layer at a relatively low temperature. Therefore, the process temperature can be lowered as compared with the case where the porous semiconductor layer is oxidized by the rapid heating method to form the strong electric field drift layer, and the material of the conductive substrate is formed. , The area can be increased and the cost can be reduced. In addition, the electron emission characteristics have a small dependence on the degree of vacuum and can stably emit electrons without generating a popping phenomenon during electron emission. There is an effect that a field emission electron source can be provided. According to a tenth aspect, in the eighth aspect, the electrolyte solution is made of an acid, which is a preferable embodiment.

According to an eleventh aspect of the present invention, in the ninth aspect of the present invention, the main oxidation treatment step oxidizes the porous semiconductor layer in a liquid. In the case of forming by this, the porous semiconductor layer can be oxidized by wet treatment subsequent to the anodic oxidation treatment, so that the process can be simplified as compared with the case of oxidizing by the rapid heating method after the anodic oxidation treatment. This has the effect.

[0173]

A thirteenth aspect of the present invention is the invention according to the eighth to twelfth aspects, wherein at least one of the steps before and after the main oxidation treatment step is performed by oxidizing the porous semiconductor layer by a thermal oxidation method. Since the oxidation process is provided, there is an effect that the electron emission efficiency can be increased.

According to a fourteenth aspect of the present invention, in the invention of the eighth to twelfth aspects, a pre-oxidation step of oxidizing the porous semiconductor layer with an oxidizing solution is provided before the main oxidation step. This has the effect of increasing the electron emission efficiency . The invention according to claim 15 is electrically conductive.
The substrate and the oxidized multi-layer formed on one surface side of the conductive substrate
A strong electric field drift layer comprising a porous semiconductor layer;
And a conductive thin film formed on the lift layer.
Applying voltage with the film as the positive electrode to the conductive substrate
Electron injected from conductive substrate due to strong electric field drift
Field emission drifting through a layer and emitted through a conductive thin film
A method for producing a type electron source, comprising:
In the conversion, the porous semiconductor layer is acidified at a relatively low temperature.
The main oxidation treatment step is
At least one of before and after, the thermal oxidation method
It has an auxiliary oxidation process for oxidizing the porous semiconductor layer.
Oxidizes the porous semiconductor layer by the rapid heating method
Process temperature lower than when forming a drift layer
Less restrictions on conductive substrate materials
Field emission type, which enables large area and low cost.
It has the effect of being able to provide offspring,
At least one of before and after the main oxidation treatment step.
On the other hand, the porous semiconductor layer is oxidized by a thermal oxidation method.
Efficiency of electron emission by having auxiliary oxidation process
There is an effect that can be increased. Claim 16
The invention comprises a conductive substrate and a conductive substrate formed on one surface side.
Field drift layer composed of a oxidized porous semiconductor layer
And a conductive thin film formed on the strong electric field drift layer.
Voltage with the conductive thin film as the positive electrode with respect to the conductive substrate.
The electrons injected from the conductive substrate by applying
Drift strong electric field drift layer and emit through conductive thin film
Method for producing a field emission type electron source,
The porous semiconductor layer is oxidized at a relatively low temperature.
A main oxidation treatment step of oxidizing the porous semiconductor layer, wherein the main acid
Before the chemical treatment process, the porous semiconductor
Since it has a pre-oxidation treatment step to oxidize the layer,
The conductor layer is oxidized by the rapid heating method to form a strong electric field drift layer.
The process temperature can be reduced compared to when forming
It is possible to reduce the restrictions on the material of the conductive substrate,
To provide a reduction and cost reduction can be field emission electron source
The main oxidation
Before the processing step, the porous semiconductor layer is oxidized with an oxidizing solution.
By providing a pre-oxidation process for oxidizing
This has the effect of increasing the efficiency of release of water.

According to a seventeenth aspect of the present invention, a strong electric field drift layer comprising a conductive substrate, an oxidized porous semiconductor layer formed on one surface side of the conductive substrate, and a strong electric field drift layer formed on the strong electric field drift layer An electric field emission, wherein electrons injected from the conductive substrate are drifted through the strong electric field drift layer and emitted through the conductive thin film by applying a voltage with the conductive thin film as a positive electrode with respect to the conductive substrate. In the method of manufacturing a porous electron source, the oxidation of the porous semiconductor layer is performed by oxidizing the porous semiconductor layer with an oxidizing solution before oxidizing the porous semiconductor layer by a thermal oxidation method. Since it has a treatment process, the thermal oxidation method is applied to the porous semiconductor layer whose surface is oxidized by the oxidizing solution, compared with the case where the rapid heating method is applied immediately after the anodizing treatment. Since there is little mixing of hydrogen into the electric field drift layer, there is little decrease in electron emission efficiency due to a change over time in the distribution of hydrogen as in the past, and the oxide film tends to be denser and the withstand voltage increases. is there. The invention according to claim 18 provides a conductive substrate, a strong electric field drift layer comprising an oxidized porous semiconductor layer formed on one surface side of the conductive substrate, and a conductive thin film formed on the strong electric field drift layer Oxidized porous material that is a strong electric field drift layer
The semiconductor layer is formed on at least a surface of the microcrystalline silicon layer formed of a columnar polycrystalline silicon formed on the one surface side of the conductive substrate, a nanostructure interposed between the polycrystalline silicon, and a microcrystalline silicon layer. And a silicon oxide film having a film thickness smaller than the crystal grain size of the microcrystalline silicon layer. Electrons injected from the conductive substrate are applied by applying a voltage to the conductive thin film as a positive electrode with respect to the conductive substrate. A method for manufacturing a field emission type electron source that drifts through a strong electric field drift layer and is emitted through a conductive thin film, wherein the porous semiconductor layer is oxidized before the porous semiconductor layer is oxidized by a thermal oxidation method. Since the pre-oxidation process of oxidizing the porous semiconductor layer with an oxidizing solution is provided, the surface of the porous semiconductor layer oxidized by the oxidizing solution is subjected to a thermal oxidation method. As compared with the case where the rapid heating method is applied immediately after the anodic oxidation treatment, the amount of hydrogen mixed into the strong electric field drift layer is small, so that the electron emission efficiency due to the temporal change of the hydrogen distribution as in the conventional case is obtained. Of the oxide film is likely to be dense, and the dielectric strength is increased. In addition, there is an effect that it is possible to provide a field emission type electron source which has a small degree of vacuum dependence of the electron emission characteristics and is capable of stably emitting electrons without generating a popping phenomenon during electron emission.

The invention of claim 19 is the invention of claim 13 or
In the invention according to claim 15, a pre-oxidation step of oxidizing the porous semiconductor layer with an oxidizing solution is provided before the main oxidation step and the auxiliary oxidation step, so that the electron emission efficiency is improved. There is an effect that can be.

According to a twentieth aspect of the present invention, in the ninth aspect of the present invention, the main oxidizing step is a step of irradiating the porous semiconductor layer with ultraviolet light in a gas atmosphere containing at least one of oxygen and ozone. Exposing the porous semiconductor layer to plasma in a gas atmosphere containing at least one of ozone and ozone, heating the porous semiconductor layer in a gas atmosphere containing at least ozone, and irradiating the porous semiconductor layer with ultraviolet light. And heating the porous semiconductor layer and heating the porous semiconductor layer while irradiating the porous semiconductor layer with ultraviolet light in a gas atmosphere containing at least one of oxygen and ozone. Since the porous semiconductor layer is oxidized by the two treatments, the porous semiconductor layer is oxidized by a rapid heating method to form a strong electric field drift layer. It is possible to increase the electron emission efficiency as compared with the case, and to form the strong electric field drift layer at a lower temperature than in the case where the porous semiconductor layer is oxidized by the rapid heating method to form the strong electric field drift layer. As a result, there is an effect that the process temperature is lowered, the restriction on the conductive substrate is reduced, and the area and cost can be easily reduced.

According to a twenty-first aspect of the present invention, a strong electric field drift layer comprising a conductive substrate, an oxidized porous semiconductor layer formed on one surface side of the conductive substrate, and a high electric field drift layer formed on the strong electric field drift layer An electric field emission, wherein electrons injected from the conductive substrate are drifted through the strong electric field drift layer and emitted through the conductive thin film by applying a voltage with the conductive thin film as a positive electrode with respect to the conductive substrate. A method of manufacturing a type electron source, comprising: forming a conductive thin film, irradiating ultraviolet light in a gas atmosphere containing at least one of oxygen and ozone, and performing plasma treatment in a gas atmosphere containing at least one of oxygen and ozone. , Heat treatment in a gas atmosphere containing at least ozone, heat treatment while irradiating ultraviolet light, gas atmosphere containing at least one of oxygen and ozone Since at least one of the processes of irradiating ultraviolet light and heating is performed in the process, it is possible to remove contamination by organic substances in a process before the process by performing the process, and to increase an electron emission efficiency. There is an effect that can be.

The invention according to claim 22 is the invention according to claim 20 or 21 , wherein at least one of before and after the main oxidation step, an auxiliary oxidation method for oxidizing the porous semiconductor layer by a thermal oxidation method. Since the processing step is provided, there is an effect that the electron emission efficiency can be increased.

[0181] The invention of claim 23 is the invention of claim 20 or claim 21, in at least one of the previous and subsequent of the main oxidation process, the auxiliary oxidation process for oxidizing the porous semiconductor layer by an acid Since the process is provided, there is an effect that the electron emission efficiency can be increased.

[0182] The invention of claim 24 is the invention of claim 20 or claim 21, in front of the main oxidation process,
Since the pre-oxidation process for oxidizing the porous semiconductor layer with an oxidizing solution is provided, hydrogen atoms that terminate atoms on the surface of the porous semiconductor layer when the porous semiconductor layer is formed by anodic oxidation treatment are removed. Since the oxygen atoms are substituted by the oxidizing solution, the amount of hydrogen contained in the strong electric field drift layer can be reduced, and the temporal change in the distribution of hydrogen in the strong electric field drift layer can be reduced. To improve the stability over time . Contract
25. The invention according to claim 25, wherein the conductive substrate and one surface of the conductive substrate
Electric field consisting of oxidized porous semiconductor layer formed on the side
A drift layer, and a conductive layer formed on the strong electric field drift layer.
A conductive thin film and a conductive thin film
Injected from the conductive substrate by applying a voltage as
Electrons drift in the strong electric field drift layer to form a conductive thin film.
Of producing a field emission type electron source emitted through
Therefore, the oxidation of the porous semiconductor layer is relatively low.
A main oxidation treatment step for oxidizing the porous semiconductor layer at a temperature
In addition, the above main oxidation treatment process includes at least oxygen and ozone.
UV light is applied to the porous semiconductor layer in a gas atmosphere containing
Irradiation, including at least one of oxygen and ozone.
Exposing the porous semiconductor layer to plasma in a gas atmosphere
Processing, porous at least in a gas atmosphere containing ozone
Heat treatment of the semiconductor layer, ultraviolet light on the porous semiconductor layer
Irradiate light and heat the porous semiconductor layer
Processing, gas atmosphere containing at least one of oxygen and ozone
The porous semiconductor layer is irradiated with ultraviolet light by
Among the processes for heating the porous semiconductor layer, at least
By one treatment, the porous semiconductor layer is oxidized,
Before and / or after the main oxidation process, heat
An auxiliary oxidation treatment for oxidizing the porous semiconductor layer by an oxidation method
Process, so that the porous semiconductor layer is
Compared with the case of forming a strong electric field drift layer by oxidation
The electron emission efficiency can be increased, and the porous semiconductor
The body layer is oxidized by the rapid heating method to form a strong electric field drift layer.
Form a strong electric field drift layer at a lower temperature than when forming
The process temperature can be lowered and the conductive substrate
Restrictions, making it easy to increase area and reduce costs
Has the effect of becoming The invention according to claim 26 is an electroconductive device.
The substrate and the oxidized multi-layer formed on one surface side of the conductive substrate
A strong electric field drift layer comprising a porous semiconductor layer;
And a conductive thin film formed on the lift layer.
Applying voltage with the film as the positive electrode to the conductive substrate
Electron injected from conductive substrate due to strong electric field drift
Field emission drifting through a layer and emitted through a conductive thin film
A method for producing a type electron source, comprising:
In the conversion, the porous semiconductor layer is acidified at a relatively low temperature.
A main oxidation treatment step, wherein the main oxidation treatment step comprises:
In a gas atmosphere containing at least one of oxygen and ozone
Treatment of irradiating the porous semiconductor layer with ultraviolet light, oxygen and oxygen
In a gas atmosphere containing at least one of
Exposing the conductor layer to plasma, including at least ozone
Heating the porous semiconductor layer in a gas atmosphere,
Irradiating the porous semiconductor layer with ultraviolet light,
A treatment for heating the porous semiconductor layer, and a reduction in oxygen and ozone
In a gas atmosphere containing at least one, purple
The porous semiconductor layer is heated while irradiating external light.
Porosity by at least one of the treatments
Before and after the main oxidation process
And at least one of the above-mentioned porous semiconductor layer
Since it has an auxiliary oxidation process for oxidation,
The body layer is oxidized by the rapid heating method to form a strong electric field drift layer.
The electron emission efficiency can be increased compared to when forming
And a rapid addition of the porous semiconductor layer.
When oxidizing by a thermal method to form a strong electric field drift layer
It is possible to form a strong electric field drift layer at a lower temperature than
Process temperature is low and the restrictions on conductive substrates are
And it is easy to increase the area and reduce the cost.
Has the effect. The invention of claim 27 is characterized in that the conductive substrate
Oxidized porous semiconductor formed on one side of conductive substrate
Electric field drift layer consisting of a layer and on the strong electric field drift layer
And a conductive thin film formed on the conductive film.
Conduction by applying voltage as positive electrode to substrate
Electrons injected from the conductive substrate drift the strong electric field drift layer
Of a field emission electron source emitted through a thin conductive film
A method for producing the porous semiconductor layer, the method comprising:
A main acid that oxidizes the porous semiconductor layer at a relatively low temperature.
The main oxidation treatment step comprises oxygen and oxygen.
In a gas atmosphere containing at least one of
Processing of irradiating ultraviolet light to the conductor layer, little of oxygen and ozone
The porous semiconductor layer is pressed in a gas atmosphere containing at least one of them.
Plasma exposure treatment, gas atmosphere containing at least ozone
Heating the porous semiconductor layer with air,
The semiconductor layer is irradiated with ultraviolet light and the porous semiconductor
Treatment of heating the layer, at least one of oxygen and ozone
Irradiates the porous semiconductor layer with ultraviolet light in a gas atmosphere containing
And heating the porous semiconductor layer.
That is, the porous semiconductor layer is formed by at least one process.
And oxidize it with an oxidizing solution before the main oxidation process.
Pre-oxidation process for oxidizing the porous semiconductor layer
Oxidize the porous semiconductor layer by the rapid heating method.
Emission of electrons compared to the case of forming a strong electric field drift layer
The effect is that the efficiency can be increased.
Electric field drift by oxidizing porous semiconductor layer by rapid heating method
In comparison with the case of forming a
Can be formed, process temperature becomes low and conductive
Less restrictions on flexible substrates, larger area and lower cost
This has the effect of making it easier. Moreover, the main oxidation treatment
Before the process, the porous semiconductor layer is oxidized with an oxidizing solution.
Since it has a pre-oxidation process for oxidation, it is a porous semiconductor
When the layer is formed by anodizing, the porous semiconductor layer
Hydrogen atoms that terminate atoms on the surface are
The strong electric field drift
The amount of hydrogen contained in the layer can be reduced
The time-dependent change in the distribution of hydrogen in the strong electric field drift layer
The effect of improving the stability over time.
There is fruit.

[0183] The invention of claim 28 is the invention of claim 22 or claim 23 or claim 25 or claim 26, before the main oxidation process and the auxiliary oxidation process, the by oxidizing solution Since the pre-oxidation process for oxidizing the porous semiconductor layer is provided, hydrogen atoms terminating atoms on the surface of the porous semiconductor layer when the porous semiconductor layer is formed by anodic oxidation are treated with an oxidizing solution. Since it is substituted with oxygen atoms, the amount of hydrogen contained in the strong electric field drift layer can be reduced, and the temporal change in the distribution of hydrogen in the strong electric field drift layer can be reduced. There is an effect that stability is improved.

According to a twenty- ninth aspect of the present invention, in the eighth to twenty- eighth aspects of the present invention, the porous semiconductor layer is made of porous single-crystal silicon, so that the strong electric field drift layer is made of Si.
An oxide film having a high density close to the structure of O ₂ or SiO ₂ is provided, so that the density and quality of the oxide film are improved, the electron emission efficiency is improved, and the withstand voltage is increased. There is.

According to the invention of claim 30, in the invention of claims 8 to 28 , since the porous semiconductor layer is made of porous polycrystalline silicon, the strong electric field drift layer is made of Si.
An oxide film having a high density close to the structure of O ₂ or SiO ₂ is provided, so that the density and quality of the oxide film are improved, the electron emission efficiency is improved, and the withstand voltage is increased. There is.

[0186] The invention of claim 32 is the invention of claim 8 through claim 30, the conductive substrate is so composed of a formed on one surface side of the insulating substrate and the insulating substrate conductive film, There is an effect that the area can be increased and the cost can be reduced as compared with the invention of claim 24.

[0187] The invention of claim 38 is the invention of claim 37, said oxidizing solvent solution, because it is heated to the oxidation speed increases, it is possible to shorten the processing time by the oxidizing solution This has the effect of improving the throughput.

According to a thirty-ninth aspect of the present invention, there is provided a space between the field emission type electron source according to any one of the first to seventh aspects and a field emission type electron source which is disposed to face the field emission type electron source. Is maintained in a vacuum, a collector electrode provided on the face plate on the side facing the field emission electron source, and a field emission type provided on the collector electrode on the side facing the field emission electron source. 7. A field emission type according to claim 1, further comprising: a phosphor layer which emits light in a visible light region by receiving an electron beam from an electron source. Since the electron source is provided, there is an effect that the area can be increased and the cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing a first embodiment.

FIG. 2 is a main process sectional view for explaining the manufacturing process of the above.

FIG. 3 is a schematic sectional view of another configuration example of the above.

FIG. 4 is an explanatory view schematically illustrating the oxidation process of the above.

FIG. 5 is a diagram illustrating the principle of the electron emission mechanism of the above.

FIG. 6 is an operation explanatory view of the above.

FIG. 7 is a voltage-current characteristic diagram of the example of the above.

FIG. 8 is a schematic sectional view showing a fourth embodiment.

FIG. 9 is a schematic sectional view showing another configuration example of the above.

FIG. 10 is a main process sectional view for explaining the manufacturing process of the above.

FIG. 11 is an operation explanatory diagram of the fifth embodiment.

FIG. 12 is a voltage-current characteristic diagram of the example of the above.

FIG. 13 is a voltage-current characteristic diagram of another embodiment of the above.

FIG. 14 is an explanatory diagram of an oxidized state of a microcrystalline silicon layer according to the sixth embodiment.

FIG. 15 is an explanatory diagram of an oxidation state of a microcrystalline silicon layer relating to the above.

FIG. 16 is a schematic perspective view of a display using the field emission type electron source according to the fourteenth embodiment.

FIG. 17 is a schematic sectional view of a display using the same field emission electron source as that of the above.

FIG. 18 is a characteristic diagram of the above.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 n-type silicon substrate 2 ohmic electrode 3 polycrystalline silicon layer 6 strong electric field drift layer 7 conductive thin film 10 field emission electron source

──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Takuya Komoda 1048 Kadoma Kadoma, Osaka Prefecture Matsushita Electric Works, Ltd. Inventor Tsutomu Ishihara 1048, Kazuma Kadoma, Kadoma City, Osaka Prefecture, Japan (72) Inventor Yukihiro Kondo 1048, Kazuma Kadoma, Kadoma City, Osaka Prefecture Inside Matsushita Electric Works, Ltd. 6-5-10-203 Mizumotocho (56) References JP-A-9-259795 (JP, A) JP-A-8-162668 (JP, A) JP-A-10-269932 (JP, A) 6-21509 (JP, A) Patent 2968442 (JP, B1) Takabe Takashi et al., "Cold electron emission from porous SiC diode", Proceedings of the 46th Joint Lecture Meeting on Applied Physics March 1999, 29p-YC-8 (58 ) investigated the field (Int.Cl. ^7, DB name) H01J 1/312 H01J 9/02 H01J 31/12 H01L 33/00

Claims (39)

(57) [Claims] 1. A conductive substrate comprising: a conductive substrate; a strong electric field drift layer formed on one surface side of the conductive substrate; and a conductive thin film formed on the strong electric field drift layer. A field emission type electron source in which electrons injected from the conductive substrate are drifted through the strong electric field drift layer and emitted through the conductive thin film by applying a voltage as a positive electrode to the substrate, and the strong electric field drift layer is Electrolyte porous semiconductor layer
A field emission type electron source formed by a process including an oxidation step of electrochemically oxidizing in a solution . 2. A conductive substrate comprising: a conductive substrate; a strong electric field drift layer formed on one surface side of the conductive substrate; and a conductive thin film formed on the strong electric field drift layer. A field emission type electron source in which electrons injected from the conductive substrate are drifted through the strong electric field drift layer and emitted through the conductive thin film by applying a voltage as a positive electrode to the substrate, and the strong electric field drift layer is Many porous semiconductor layers
Is formed by a process comprising oxidation step of relatively oxidized at low temperatures porous polycrystalline silicon layer, even without small, the polycrystalline silicon of the pillar formed on the first surface side of the conductive substrate, between the polycrystalline silicon A field emission type comprising a microcrystalline silicon layer having an interposed nanostructure and a silicon oxide film formed on the surface of the microcrystalline silicon layer and having a thickness smaller than the crystal grain size of the microcrystalline silicon layer. Electron source. 3. The method according to claim 1, wherein the oxidizing step comprises the steps of :
3. The field emission type electron source according to claim 2 , wherein the step is a step of oxidizing a body layer . 4. The field emission type electron source according to claim 3 , wherein said liquid comprises an acid . 5. The method according to claim 1, wherein the acid is HNO ₃ , H ₂ SO ₄ or aqua regia.
The field emission type electron source according to claim 4, which is selected from the group consisting of: 6. The method according to claim 1, wherein the porous semiconductor layer is made of porous single crystal silicon.
6. The field emission type electron source according to any one of 5 . 7. The porous semiconductor layer is formed of a porous polycrystalline silicon.
Claim 1 or Claim 2 comprising a recon.
6. The field emission type electron source according to any one of 5. 8. A conductive substrate and one surface side of the conductive substrate.
Strong electric field drill consisting of oxidized porous semiconductor layer formed
And a conductive thin film formed on the strong electric field drift layer.
A conductive thin film as a positive electrode with respect to the conductive substrate.
Injected from the conductive substrate by applying a voltage
Electrons drift in the strong electric field drift layer and pass through the conductive thin film
A method for producing a field emission electron source emitted by
When oxidizing the porous semiconductor layer,
A main oxidation process for oxidizing the porous semiconductor layer;
In the main oxidation treatment step, the porous semiconductor layer is placed in an electrolyte solution.
In the manufacturing method of to that electric field emission electron source, characterized in that the electrochemically oxidized. 9. A conductive substrate, a strong electric field drift layer formed of an oxidized porous semiconductor layer formed on one surface side of the conductive substrate, and a conductive thin film formed on the strong electric field drift layer. Oxidized porous semi-conductor, which is a strong electric field drift layer
The conductor layer is formed on at least the surface of the columnar polycrystalline silicon formed on the one surface side of the conductive substrate, the microcrystalline silicon layer having a nanostructure interposed between the polycrystalline silicon, and the surface of the microcrystalline silicon layer. And a silicon oxide film having a thickness smaller than the crystal grain size of the microcrystalline silicon layer,
A method of manufacturing a field emission type electron source in which electrons injected from a conductive substrate are drifted through a strong electric field drift layer and emitted through the conductive thin film by applying a voltage with the conductive thin film as a positive electrode with respect to the conductive substrate. A method of manufacturing a field emission type electron source, comprising: oxidizing the porous semiconductor layer at a relatively low temperature with a main oxidation process. 10. The method according to claim 8 , wherein said electrolyte solution comprises an acid . 11. The main oxidation treatment step includes the step of:
The method according to claim 9, wherein the porous semiconductor layer is oxidized . 12. The method according to claim 11 , wherein the liquid comprises an acid . 13. The method according to claim 1, wherein said pre- oxidation process is performed before and after said main oxidation process .
At least one manufacturing method of a field emission electron source according to any one of claims 8 to 12 by thermal oxidation, characterized in that it comprises a row intends auxiliary oxidation process the oxidation of the porous semiconductor layer . 14. An oxidizing solution prior to the main oxidation treatment step.
Claims 8 to the liquid you, comprising an oxidation process before performing the oxidation of the porous semiconductor layer 12
Method for producing the electric field emission electron source according to any one of. 15. A conductive substrate, and one surface side of the conductive substrate.
Electric field composed of oxidized porous semiconductor layer formed on
Lift layer and a conductive layer formed on the strong electric field drift layer.
And a thin film, wherein the conductive thin film is
Is injected from the conductive substrate by applying a voltage
Electrons drift in the strong electric field drift layer and pass through the conductive thin film.
A method for manufacturing a field emission electron source emitted as
In oxidizing the above porous semiconductor layer, at a relatively low temperature
Comprising a main oxidation process of oxidizing the porous semiconductor layer,
At least one of before and after the main oxidation process
In addition, supplementary oxidation of the porous semiconductor layer by a thermal oxidation method
Method of manufacturing to that electric field emission electron source, wherein the obtaining Bei auxiliary oxidation process. 16. A conductive substrate and one surface side of the conductive substrate.
Electric field composed of oxidized porous semiconductor layer formed on
Lift layer and a conductive layer formed on the strong electric field drift layer.
And a thin film, wherein the conductive thin film is
Is injected from the conductive substrate by applying a voltage
Electrons drift in the strong electric field drift layer and pass through the conductive thin film.
A method for manufacturing a field emission electron source emitted as
In oxidizing the above porous semiconductor layer, at a relatively low temperature
Comprising a main oxidation process of oxidizing the porous semiconductor layer,
Prior to the main oxidation process, the porous
Method of manufacturing features and to that electric field emission electron source further comprising an oxidation process before performing the oxidation of the quality semiconductor layer. 17. A conductive substrate, a strong electric field drift layer formed of an oxidized porous semiconductor layer formed on one surface side of the conductive substrate, and a conductive thin film formed on the strong electric field drift layer. Manufacturing of a field emission type electron source in which electrons injected from a conductive substrate drift in a strong electric field drift layer and are emitted through the conductive thin film by applying a voltage with the conductive thin film as a positive electrode with respect to the conductive substrate. there is provided a method,
In oxidizing the porous semiconductor layer, a thermal oxidation method is used.
Before oxidizing the porous semiconductor layer,
The pre-oxidation process for oxidizing the porous semiconductor layer
A method for manufacturing a field emission type electron source, comprising: 18. A conductive substrate, a strong electric field drift layer comprising an oxidized porous semiconductor layer formed on one surface side of the conductive substrate, and a conductive thin film formed on the strong electric field drift layer. Oxidized porous with strong electric field drift layer
The semiconductor layer is formed on at least a surface of the microcrystalline silicon layer formed of a columnar polycrystalline silicon formed on the one surface side of the conductive substrate, a nanostructure interposed between the polycrystalline silicon, and a microcrystalline silicon layer. And a silicon oxide film having a film thickness smaller than the crystal grain size of the microcrystalline silicon layer. Electrons injected from the conductive substrate are applied by applying a voltage to the conductive thin film as a positive electrode with respect to the conductive substrate. A method for manufacturing a field emission type electron source that drifts through a strong electric field drift layer and is emitted through a conductive thin film, wherein the porous semiconductor layer is oxidized before the porous semiconductor layer is oxidized by a thermal oxidation method. Further comprising a pre-oxidation process of oxidizing the porous semiconductor layer with an oxidizing solution. 19. The main oxidation treatment over extent and the auxiliary acid
Before the treatment process, the production of the field emission electron source according to claim 13 or claim 15 wherein, characterized in that it comprises more said porous line power sale before the oxidation process the oxide semiconductor layer to an oxidizing solution Method. 20. extent the main oxidation process over the oxygen and ozone
The above porous semiconductor in a gas atmosphere containing at least one of
Irradiation of body layer with ultraviolet light, less oxygen and ozone
The porous semiconductor layer in a gas atmosphere containing
Exposure to zuma, gas atmosphere containing at least ozone
Heating the porous semiconductor layer with the porous semiconductor layer
Irradiating the conductor layer with ultraviolet light and the porous semiconductor layer
Heat treatment, at least one of oxygen and ozone
Irradiating the porous semiconductor layer with ultraviolet light in a gas atmosphere containing
And heating the porous semiconductor layer.
That is, the porous semiconductor layer is formed by at least one process.
Method of manufacturing a field emission electron source according to claim 9, wherein the oxidation of. 21. A conductive substrate and one surface side of the conductive substrate
Electric field composed of oxidized porous semiconductor layer formed on
Lift layer and a conductive layer formed on the strong electric field drift layer.
And a thin film, wherein the conductive thin film is
Is injected from the conductive substrate by applying a voltage
Electrons drift in the strong electric field drift layer and pass through the conductive thin film.
A method for manufacturing a field emission electron source emitted as
After forming the conductive thin film, at least oxygen and ozone
Irradiation with ultraviolet light in a gas atmosphere containing one, oxygen
Plasma in a gas atmosphere containing at least one of
Exposure to a gas atmosphere containing at least ozone
Heating treatment, UV light irradiation and heating
Processing, gas atmosphere containing at least one of oxygen and ozone
Of the process of irradiating UV light with air and heating
Method of manufacturing to that electric field emission electron source comprising: a main oxidation process for performing at least one process. 22. A method according to claim 1, wherein said pre-oxidation process is performed before and after said main oxidation process.
At least one of the porous semiconductor layers is formed by a thermal oxidation method.
22. The method for manufacturing a field emission type electron source according to claim 20, further comprising an auxiliary oxidation treatment step of oxidizing . 23. A method according to claim 1, wherein said pre-oxidation process is performed before and after said main oxidation process.
Oxidation of the porous semiconductor layer by an acid
22. The method for manufacturing a field emission electron source according to claim 20 , further comprising an auxiliary oxidation treatment step of performing . 24. An oxidizing solution prior to the main oxidation treatment step.
Pre-oxidation treatment for oxidizing the porous semiconductor layer with a liquid
21. The method according to claim 20, further comprising the steps of :
2. The method for manufacturing a field emission electron source according to claim 1 . 25. A conductive substrate and one surface side of the conductive substrate
Electric field composed of oxidized porous semiconductor layer formed on
Lift layer and a conductive layer formed on the strong electric field drift layer.
And a thin film, wherein the conductive thin film is
Is injected from the conductive substrate by applying a voltage
Electrons drift in the strong electric field drift layer and pass through the conductive thin film.
A method for manufacturing a field emission electron source emitted as
In oxidizing the above porous semiconductor layer, at a relatively low temperature
Comprising a main oxidation process of oxidizing the porous semiconductor layer,
The main oxidation treatment step includes at least one of oxygen and ozone.
Irradiating the porous semiconductor layer with ultraviolet light in a gas atmosphere containing
Irradiation, gas containing at least one of oxygen and ozone
Exposing the porous semiconductor layer to plasma in a gas atmosphere.
In a gas atmosphere containing at least ozone,
Heat treatment of the conductor layer, ultraviolet light on the porous semiconductor layer
And heating the porous semiconductor layer.
Gas atmosphere containing at least one of oxygen and ozone
Irradiate the porous semiconductor layer with ultraviolet light with
Chi processing sac for heating the porous semiconductor layer, at least one
The porous semiconductor layer is oxidized by the
At least one of before and after the oxidation process, thermal acid
Oxidation treatment to oxidize the porous semiconductor layer by the oxidation method
Manufacturing method of that electric field emission electron source to, characterized in that it comprises a process. 26. A conductive substrate and one surface side of the conductive substrate
Electric field composed of oxidized porous semiconductor layer formed on
Lift layer and a conductive layer formed on the strong electric field drift layer.
And a thin film, wherein the conductive thin film is
Is injected from the conductive substrate by applying a voltage
Electrons drift in the strong electric field drift layer and pass through the conductive thin film.
A method for manufacturing a field emission electron source emitted as
In oxidizing the above porous semiconductor layer, at a relatively low temperature
Comprising a main oxidation process of oxidizing the porous semiconductor layer,
The main oxidation treatment step includes at least one of oxygen and ozone.
Irradiating the porous semiconductor layer with ultraviolet light in a gas atmosphere containing
Irradiation, gas containing at least one of oxygen and ozone
Exposing the porous semiconductor layer to plasma in a gas atmosphere.
In a gas atmosphere containing at least ozone,
Heat treatment of the conductor layer, ultraviolet light on the porous semiconductor layer
And heating the porous semiconductor layer.
Gas atmosphere containing at least one of oxygen and ozone
Irradiate the porous semiconductor layer with ultraviolet light with
At least one of the treatments for heating the porous semiconductor layer
The porous semiconductor layer is oxidized by the
Before and / or after the oxidation process, acid
Auxiliary oxidation process for oxidizing the porous semiconductor layer
Method of manufacturing to that electric field emission electron source comprising: a. 27. A conductive substrate and one surface side of the conductive substrate
Electric field composed of oxidized porous semiconductor layer formed on
Lift layer and a conductive layer formed on the strong electric field drift layer.
And a thin film, wherein the conductive thin film is
Is injected from the conductive substrate by applying a voltage
Electrons drift in the strong electric field drift layer and pass through the conductive thin film.
A method for manufacturing a field emission electron source emitted as
In oxidizing the above porous semiconductor layer, at a relatively low temperature
Comprising a main oxidation process of oxidizing the porous semiconductor layer,
The main oxidation treatment step includes at least one of oxygen and ozone.
Irradiating the porous semiconductor layer with ultraviolet light in a gas atmosphere containing
Process of elevation, gas containing at least one of oxygen and ozone
Exposing the porous semiconductor layer to plasma in a gas atmosphere.
In a gas atmosphere containing at least ozone,
Heat treatment of the conductor layer, ultraviolet light on the porous semiconductor layer
And heating the porous semiconductor layer.
Gas atmosphere containing at least one of oxygen and ozone
Irradiate the porous semiconductor layer with ultraviolet light with
At least one of the treatments for heating the porous semiconductor layer
The porous semiconductor layer is oxidized by the
Prior to the oxidation process, the porous semiconductor is oxidized with an oxidizing solution.
Manufacturing method of that electric field emission electron source to <br/> further comprising a pre-oxidation process of performing oxidation of the material layer. 28. The main oxidation treatment step and the auxiliary acid
Prior to the oxidation treatment step, the porous half
26. The method according to claim 22, further comprising a pre-oxidation process for oxidizing the conductor layer.
A method for manufacturing a field emission electron source according to claim 26 . 29. The porous semiconductor layer is a porous single crystal.
9. The method according to claim 8 , wherein the material is made of silicon.
Item 29. The method for manufacturing a field emission electron source according to any one of Items 28 to 28 . 30. The porous semiconductor layer is formed of a porous polycrystalline
9. The method according to claim 8 , wherein the material is made of silicon.
Item 29. The method for manufacturing a field emission electron source according to any one of Items 28 to 28 . 31. The conductive substrate is an n-type silicon substrate.
Characterized in that it claims 8 to 30 Neu
A method for manufacturing a field emission electron source according to any of the above . 32. The conductive substrate is insulated from an insulating substrate.
Serial to any one of claims 8 to 30 you characterized <br/> be composed of a formed on one surface side of the sexual substrate conductive film
Of manufacturing the field emission type electron source described above. 33. The insulating substrate is made of a glass substrate.
33. The field emission type electron source according to claim 32, wherein:
Manufacturing method. 34. The insulating substrate is a ceramic substrate.
33. The field emission type electric device according to claim 32, wherein
The method of manufacturing the source. 35. The semiconductor device according to claim 35, wherein the porous semiconductor layer is provided on the semiconductor layer.
Extreme oxidation treatment Characterized by being formed by
The field emission according to any one of claims 8 to 34.
Method of manufacturing a type electron source. 36. The acid comprises nitric acid, sulfuric acid, and aqua regia.
11. The method according to claim 10, wherein the group is selected from a group.
The electric field according to claim 12 or claim 23 or claim 26.
A method for manufacturing a radiation type electron source. 37. The oxidizing solution comprises nitric acid, sulfuric acid, salt
One selected from the group consisting of acids and aqueous hydrogen peroxide
2. The method according to claim 1, wherein the oxidizing agent comprises two or more oxidizing agents.
Claim 4 or Claim 16 or Claim 17 or Claim 18
Or claim 19 or claim 24 or claim 27
A method for manufacturing a field emission electron source according to claim 28. 38. The oxidizing solvent solution, a method of manufacturing a field emission electron source according to claim 37, wherein the formed by heating to the oxidation speed increases. 39. Any of claims 1 to 7
The field emission type electron source described above, and the field emission type electron source
The space between the placed field emission electron source is kept in vacuum
Faceplate and the electric field at the faceplate
Collector electrode provided on the side facing the emission electron source
Of the collector electrode facing the field emission electron source
Side to receive the electron beam from the field emission type electron source.
A phosphor layer that emits light in the visible light region.
Display to be characterized.