JP2987140B2 - Field emission electron source, method of manufacturing the same, flat light emitting device, display device, and solid-state vacuum device - Google Patents

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, a flat light emitting device using the field emission type electron source, and a method of manufacturing the same. The present invention relates to a display device and a solid-state vacuum device.

[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 Patent Application Laid-Open Publication No. H10-209, a porous semiconductor layer (for example, a 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 type electron source (semiconductor cold electron emission device) has been proposed in which a metal thin film is formed on the porous semiconductor layer, and a voltage is applied between the semiconductor substrate and the metal thin film to emit electrons. ing.

Japanese Unexamined Patent Application Publication No. 9-259975 discloses a cold electron emission display device having a field emission type electron source (semiconductor cold electron emission element) having the configuration disclosed in Japanese Patent Application Laid-Open No. 8-250766. Proposed. In this cold electron emission display device, the [100] direction of the single crystal silicon substrate is oriented perpendicular to the surface.
It is said that the porous silicon layer is preferable in terms of the electron emission efficiency. The reason for this is that (10)
0) It is presumed that when anodizing the substrate, holes are formed from the surface to a depth of several μm, and the holes and silicon crystals are oriented perpendicular to the surface.

[0007]

However, in the field emission type electron source described in JP-A-8-250766, since the substrate is limited to a semiconductor substrate, it is difficult to increase the area and reduce the cost. There is. Also, JP-A-8-250766 and JP-A-9-2597
In the field emission type electron source described in Japanese Patent Publication No. 95, so-called popping phenomenon easily occurs at the time of electron emission, and the amount of emitted electrons tends to be uneven. Therefore, when applied to a flat light emitting device or a display device, it is said that uneven emission is generated. There is a defect.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide a low-cost field emission type electron source capable of stably and efficiently emitting electrons, a method of manufacturing the same, a flat light emitting device, and a display. An apparatus and a solid-state vacuum device are provided.

[0009]

According to a first aspect of the present invention, there is provided a porous substrate having a conductive substrate and an oxidized nanometer structure formed on one surface of the conductive substrate. Comprising a polysilicon layer and a metal thin film formed on the porous polysilicon layer, and emitting an electron beam through the metal thin film by applying a voltage with the metal thin film as a positive electrode to a conductive substrate. And the above
Porous polysilicon layer makes each grain surface porous
The crystal state is not maintained at the center of each grain.
Which is caused by the application of a voltage.
The heat conducted to the part where the above crystalline state was maintained
Since electrons are emitted and the temperature rise is suppressed, the dependence of the electron emission characteristics on the degree of vacuum is small, and electrons can be emitted stably with high efficiency without the occurrence of a popping phenomenon during electron emission. In addition to a semiconductor substrate such as a single crystal silicon substrate, a substrate obtained by forming a conductive film 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.

According to a second aspect of the present invention, there is provided a conductive substrate, a porous polysilicon layer formed on one surface side of the conductive substrate and having a structure in units of nanometers, and a porous polysilicon layer formed on the porous polysilicon layer. A metal thin film formed on the conductive substrate, and applying a voltage with the metal thin film as a positive electrode to the conductive substrate to emit an electron beam through the metal thin film.
The porous polysilicon layer is formed on the surface of each grain.
Is made porous and the crystalline state is maintained at the center of each grain.
Which is characterized by comprising a lifting, application of the voltage
The heat generated by the heat is conducted through the part where the above crystalline state is maintained
As a result, since the temperature rise is suppressed by being emitted to the outside, the dependence of the electron emission characteristics on the degree of vacuum is small, and electrons can be stably emitted with high efficiency without the occurrence of a popping phenomenon during electron emission. In addition to a semiconductor substrate such as a single-crystal silicon substrate as a conductive substrate, a substrate obtained by forming a conductive film on a glass substrate or the like can be used. Compared to the case where a layer is used or a Spindt-type electrode, the area of the electron source can be increased and the cost can be reduced.

According to a third aspect of the present invention, in the first or second aspect of the present invention, the porous polysilicon layer is formed by alternately stacking a high-porosity polysilicon layer and a low-porosity polysilicon layer. Characterized in that it is a layer formed.

According to a fourth aspect of the present invention, in the first or second aspect of the present invention, the porous polysilicon layer is a layer whose porosity continuously changes in a thickness direction.

According to a fifth aspect of the present invention, in the first or second aspect of the present invention, the porous polysilicon layer has a thickness in the thickness direction such that the porosity on the conductive substrate side is higher than that on the surface side. It is characterized in that it is a layer whose porosity changes continuously.

The invention of claim 6 is the first to fifth aspects of the present invention.
In the above invention, since the polysilicon layer is a non-doped polysilicon layer, the oxidized or nitrided porous polysilicon layer becomes semi-insulating, and by applying the voltage, the porous polysilicon layer becomes strong. As an electric field, the electrons injected from the conductive substrate side into the porous polysilicon layer drift and reach the surface of the porous polysilicon layer, and the electrons are tunneled through the metal thin film as hot electrons. Since the light is emitted, electrons can be emitted more efficiently and stably than in the case where the polysilicon layer is doped, and the manufacturing becomes easy because doping is unnecessary.

The invention according to claim 7 is the invention according to claims 1 to 6.
In the invention of the above, since the conductive substrate is formed of a substrate having a conductive thin film formed on one surface, the area and cost can be reduced as compared with the case where a semiconductor substrate such as a single crystal silicon substrate is used as the conductive substrate. Will be possible.

According to an eighth aspect of the present invention, there is provided the method for manufacturing a field emission type electron source according to the first aspect, wherein a polysilicon layer is formed on a conductive substrate, and the polysilicon layer is made porous. It oxidizes the oxidized polysilicon layer and forms an electrode made of a metal thin film on the oxidized porous polysilicon layer, which requires a complicated structure and manufacturing process like the conventional Spindt-type electrode. In addition, it is possible to provide a low-cost field emission electron source that can stably and efficiently emit electrons by a relatively simple manufacturing process,
A large-area field emission electron source can be provided.

According to a ninth aspect of the present invention, there is provided the method for manufacturing a field emission type electron source according to the second aspect, wherein a polysilicon layer is formed on a conductive substrate, and the polysilicon layer is made porous. It is characterized by forming a metal thin film electrode on the nitrided porous polysilicon layer by nitriding the polysilicon layer, which requires a complicated structure and manufacturing process like the conventional Spindt-type electrode. In addition, it is possible to provide a low-cost field emission electron source that can stably and efficiently emit electrons by a relatively simple manufacturing process,
A large-area field emission electron source can be provided.

According to a tenth aspect of the present invention, in the invention of the eighth or ninth aspect, when the polysilicon layer is made porous, a polysilicon layer having a high porosity and a polysilicon layer having a low porosity are alternately formed. It is characterized in that the conditions for making porous are changed so that the layers are stacked.

According to an eleventh aspect of the present invention, in the invention of the eighth or ninth aspect, when the polysilicon layer is made porous, the porosity on the conductive substrate side is higher than that on the surface side, and the thickness in the thickness direction is increased. It is characterized in that the conditions for making porous are changed so that the porosity changes continuously.

According to a twelfth aspect of the present invention, there is provided the field emission type electron source according to any one of the first to seventh aspects, and a transparent electrode disposed to face the metal thin film, and a visible light is emitted by the electron beam. Phosphor is provided on the transparent electrode, and the emission angle of electrons emitted from the field emission type electron source is aligned in a direction substantially perpendicular to the surface of the metal thin film. Further, it is not necessary to provide a focusing electrode, so that the structure is simplified and a thin flat light emitting device can be realized.

According to a thirteenth aspect of the present invention, the field emission type electron source according to any one of the first to seventh aspects is configured in a matrix, and the voltage applied to each field emission type electron source is controlled. Means, and a transparent electrode disposed opposite to the metal thin film, wherein a phosphor which emits visible light by the electron beam is provided on the transparent electrode. Since the emission angle of the electrons emitted from the source is substantially perpendicular to the surface of the metal thin film, there is no need to provide a complicated shadow mask or electron focusing lens, and a high-definition display device can be realized.

The invention of claim 14 provides at least claim 1
The field emission type electron source and the anode according to any one of claims 7 to 7 are arranged in a vacuum vessel, and the field emission type electron source constitutes a cold cathode.
Unlike conventional solid-state vacuum devices having a hot cathode utilizing thermionic emission, there is no need to provide a heating means, which makes it possible to reduce the size and suppress evaporation and deterioration of the cathode material, and to provide a long-life solid. A vacuum device can be realized.

By the way, the present inventors have conducted intensive studies,
In the structures described in JP-A-8-250766 and JP-A-9-259975 described in the related art,
Since the main surface side of a semiconductor substrate such as a single crystal silicon substrate is made porous to form a porous layer into which electrons are injected, the field emission electron source has high heat insulation, and a voltage is applied and a current flows. It has been found that the rise in the substrate temperature in this case is relatively large. Furthermore, the electrons are thermally excited by the temperature rise, and the resistance of the semiconductor substrate is reduced, and the amount of emitted electrons is increased. Therefore, a popping phenomenon is likely to occur at the time of emitting electrons, and the amount of emitted electrons tends to be uneven. Was obtained. Then, the inventor carried out the present invention based on the above findings.

[0024]

(Embodiment 1) FIG. 1 is a schematic configuration diagram of a field emission type electron source 10 according to this embodiment, and FIGS.
(E) is a sectional view of a main step in the method for manufacturing the field emission electron source 10. In this embodiment, an n-type silicon substrate 1 (a (100) substrate having a resistivity of about 0.1 Ωcm) is used as the conductive substrate.

In the field emission type electron source 10 of the present embodiment, as shown in FIG. 1, a polysilicon layer 5 which is rapidly thermally oxidized is formed on a main surface of an n-type silicon substrate 1, and the polysilicon layer 5 is formed. Porous polysilicon layer 6 on which rapid thermal oxidation has been performed
Is formed, and a gold thin film 7 as a metal thin film is formed on the porous polysilicon layer 6. An ohmic electrode 2 is formed on the back surface of the n-type silicon substrate 1.

In this embodiment, the n-type silicon substrate 1 is used as the conductive substrate. The conductive substrate constitutes the negative electrode of the field emission type electron source 10 and has the above-mentioned porous polycrystalline structure in a vacuum. Support the silicon layer 6,
In addition, electrons are injected into the porous polysilicon layer 6. Therefore, the conductive substrate is not limited to the n-type silicon substrate, and is not limited to the n-type silicon substrate, as long as it can constitute the negative electrode of the field emission electron source 10 and support the porous polysilicon layer 6. Or a conductive film formed on one surface of an insulating substrate such as glass. In the case where a substrate in which a conductive film is formed on one surface of a glass substrate is used, the area and cost of the electron source can be increased as compared with the case where a semiconductor substrate is used.

Further, the above-mentioned porous polysilicon layer 6
This is a layer into which electrons are injected when a voltage is applied between the conductive substrate and the metal thin film. The porous polysilicon 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). Porous polysilicon layer 6
In order for the electrons injected into the nanostructure to reach the surface of the porous polysilicon layer 6 without colliding with the nanostructure (that is, without electron scattering), the size of the nanostructure is determined by the size of the electron in the single crystal silicon. Should be smaller than the mean free path of about 50 nm. Specifically, the size of the nanostructure is preferably smaller than 10 nm, and more preferably smaller than 5 nm. In the present embodiment, the porous polysilicon layer 6 is rapidly thermally oxidized, but is not limited to rapid thermal oxidation, and may be oxidized by a chemical method, or may be nitrided. Is also good.

Further, in this embodiment, the gold thin film 7 is used as the metal thin film. The metal thin film constitutes the positive electrode of the field emission electron source 10, and the electric field is applied to the porous polysilicon layer 6 by the electric field. Is applied. Electrons that reach the surface of the porous polysilicon layer 6 by applying the electric field are emitted from the surface of the metal thin film by a tunnel effect. Therefore, the energy obtained by subtracting the work function of the metal thin film from the energy of the electron obtained by the DC voltage applied between the conductive substrate and the metal thin film becomes the ideal energy of the emitted electrons. The smaller the function, the better. In the present embodiment, gold is used as the material of the metal thin film. However, the material of the metal thin film is not limited to gold, and may be any metal having a small work function, such as aluminum, chromium, and tungsten. ,
Nickel, platinum, or the like may be used. Here, the work function of gold is 5.10 eV, and the work function of aluminum is 4.2.
8 eV, the work function of chromium is 4.50 eV, the work function of tungsten is 4.55 eV, the work function of nickel is 5.15 eV, and the work function of platinum is 5.65 eV.

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

First, an ohmic electrode 2 is formed on the back surface of the n-type silicon substrate 1, and then a non-doped polysilicon layer 3 having a thickness of about 1.5 μm is formed on the surface of the n-type silicon substrate 1 as shown in FIG. A structure as shown in FIG. The polysilicon layer 3 is formed by the LPCVD method under the conditions of a vacuum degree of 20 Pa and a substrate temperature of 64.
At 0 ° C., the flow rate of the monosilane gas was set at 600 sccm.
Note that the polysilicon 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. Thus, the film may be crystallized to form a film. When the conductive substrate is a glass substrate on which a conductive thin film is formed,
By forming amorphous silicon on the conductive thin film by CVD method and annealing with excimer laser,
A polysilicon layer may be formed. Further, the method of forming a polysilicon layer on a conductive thin film is not limited to the CVD method. For example, a CGS (Continuous Grain S
(ilicon) method or catalytic CVD method.

After the non-doped polysilicon layer 3 is formed, a platinum electrode (not shown) is connected to a negative electrode by using an electrolytic solution consisting of a mixture of a 55 wt% aqueous solution of hydrogen fluoride and ethanol at a ratio of about 1: 1. By performing anodization at a constant current while irradiating the polysilicon layer 3 with light using the n-type silicon substrate 1 (ohmic electrode 2) as a positive electrode,
A porous polysilicon layer 4 (hereinafter, referred to as PPS 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 polysilicon layer 3 is irradiated with light by a 500 W tungsten lamp during the anodic oxidation. Irradiation was performed.
As a result, in this embodiment, the porous polysilicon layer 4 having a thickness of about 1 μm was formed. In the present embodiment,
Although part of the polysilicon layer 3 is made porous, the entire polysilicon layer 3 may be made porous.

Next, rapid thermal oxidation (RTO: Rapid Therm)
The structure shown in FIG. 2C is obtained by performing rapid thermal oxidation of the PPS layer 4 and the polysilicon layer 3 by the Al Oxidation (Al Oxidation) technique. Here, reference numeral 5 in FIG. 2C indicates a polysilicon layer which has been rapidly thermally oxidized, and reference numeral 6 indicates a PPS layer which has been rapidly thermally oxidized (hereinafter, referred to as an RTO-PPS layer 6). The conditions of the rapid thermal oxidation are as follows:
The oxidation time was 1 hour. In the present embodiment, PP
Since the oxidation of the S layer 4 and the polysilicon layer 3 is performed by rapid thermal oxidation, it is possible to raise the temperature to the oxidation temperature in a few seconds. Entrapment oxidation can be suppressed. Also,
In the embodiment, the PPS layer 4 and the polysilicon layer 3 are rapidly thermally oxidized by the rapid thermal oxidation technique, but not limited to the rapid thermal oxidation, and may be oxidized by a chemical method or oxidized by oxygen plasma. Good. In addition, nitriding may be performed instead of oxidation. In the case of nitriding, a method such as nitriding by nitrogen plasma or thermal nitriding may be used.

Next, a gold thin film 7 as a metal thin film is formed on the RTO-PPS layer 6 by, for example, vapor deposition.
Field emission type electron source 10 having the structure shown in FIG. 2D (FIG. 1).
Is obtained. Here, in the present embodiment, the thickness of the gold thin film 7 is set to approximately 10 nm, but this thickness is not particularly limited. The field emission electron source 10 has a diode in which the gold 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). Further, in this embodiment, the metal thin film is formed by vapor deposition, but the method of forming the metal thin film is not limited to vapor deposition, and for example, a sputtering method may be used.

Hereinafter, the field emission type electron source 10 of this embodiment will be described.
Will be described.

The above-mentioned field emission type electron source 10 is introduced into a vacuum chamber (not shown), and a collector electrode 21 (radiation electron collection electrode) is arranged at a position facing the gold thin film 7 as shown in FIG. And reduce the degree of vacuum in the vacuum chamber to about 5 × 10 ^−5.
As Pa, a DC voltage Vps is applied between the gold thin film 7 and the ohmic electrode 2, and a DC voltage Vc is applied between the collector electrode 21 and the gold thin film 7. Between the collector electrode 21 and the gold thin film 7 due to the diode current Ips flowing between the collector electrode 21 and the electron e ⁻ (the dashed line in FIG. 3 indicates the radiated electron flow) emitted from the field emission type electron source 10 through the gold thin film 7. FIG. 4 shows the result of measurement of the emission electron current Ie flowing between. Here, the gold thin film 7 is connected to the ohmic electrode 2 (that is, n
A DC voltage Vps is applied as a positive electrode to the silicon substrate 1), and a DC voltage Vc is applied to the collector electrode 21 as a positive electrode to the thin gold film 7.

The horizontal axis of FIG. 4 shows the value of the DC voltage Vps, and the vertical axis shows the current density. In FIG.
ps, and b (●) in the figure indicates the emission electron current Ie. Note that the DC voltage Vc was kept constant at 100V.

As can be seen from FIG. 4, the emission electron current I
e is observed only when the DC voltage Vps is positive.
As the value of ps was increased, both the diode current Ips and the emission electron current Ie increased. For example, when the DC voltage Vps is 15 V, the current density of the diode current Ips is approximately 100 mA / cm ² , and the current density of the emission electron current Ie is approximately 1
0 μA / cm ² , and the value of the emission electron current Ie is larger than that of the field emission electron source realized by making the surface of the single crystal silicon substrate porous as described in the conventional example (for example, , IEICE ED96-14
1, P41-46, when the DC voltage Vps is 15 V, the current density of the diode current Ips is approximately 40 mA /
cm ² , and the current density of the emission electron current Ie is approximately 1 μA / cm ²
It can be seen that the electron emission efficiency of the field emission electron source 10 of the present embodiment is high.

FIG. 5 shows data on the emission electron current Ie and the DC voltage Vps by Fowler-Nordhei.
The result of m (Fowler-Nordheim) plot is shown. From FIG. 5, since each data is on a straight line, it is inferred that this emission electron current Ie is a current due to emission of electrons due to the quantum tunnel effect. The electron emission mechanism at this time will be described with reference to the energy band diagram of FIG. In FIG. 6, n ⁺ -Si denotes the n-type silicon substrate 1 and RT
O-PPS is the RTO-PPS layer 6 described above, SiO _X is silicon oxide thin film formed on the outermost surface of the RTO-PPS layer 6, Au is gold thin film 7, E _F is the Fermi level, E
_VAC indicates the vacuum level, respectively. FIG. 6 (a)
6 shows a state before the DC voltage Vps is applied, and FIG. 6B shows a state when the DC voltage Vps is applied. Gold thin film 7
A DC voltage Vps is applied to the silicon substrate 1 as a positive electrode, and when the DC voltage Vps reaches a predetermined value (critical value), as shown in FIG. Electrons e ⁻ are injected into the PPS layer 6 by thermal excitation. At this time, since most of the DC voltage Vps is applied to the semi-insulating RTO-PPS layer 6, the injected electrons e ⁻ are exposed to the strong electric field existing in the RTO-PPS layer 6 (the average electric field is approximately 10 ⁵ V). / Cm), and moves toward the surface while losing kinetic energy due to scattering of irregular potentials and lattices. (In this process, electron doubling due to impact ionization may occur.) RTO-P
The electrons e ⁻ arriving at the surface of the PS layer 6 are considered to be so-called hot electrons (hot electrons) having a higher kinetic energy than the thermal equilibrium state, and the RTO-P
The thin gold film 7 is easily inferred as being tunnel release to the outside through the SiO _X subbands outermost surface of the PS layer 6.

In order to confirm this theory, the energy N of electrons emitted from the field emission type electron source 10 of this embodiment is
FIG. 7 shows the result of measuring the energy distribution of (E). In FIG. 7, A is when the DC voltage Vps is 12 V, B is when the DC voltage Vps is 15 V, and C is the DC voltage Vps.
Is 18 V, respectively. From FIG. 7, the energy distribution of the energy N (E) of the electrons is relatively broad and includes a high energy component of several eV.
It has been found that the peak position shifts to the higher energy side as the applied DC voltage Vps increases. Therefore, R
The electron scattering in the TO-PPS layer 6 is small, and the RTO-PP
The electrons reaching the surface side of the S layer 6 are considered to be hot electrons having sufficient energy. FIG.
The figure in the circle A indicated by the two-dot chain line in the figure qualitatively shows the relationship between the energy distribution n (E) of the electrons immediately before emission and the tunnel emission probability T (E). The shape of the energy distribution of energy N (E) is determined by multiplying n (E) by T (E) (N (E) = n (E) T (E)).
For example, when the voltage of the DC voltage Vps increases, n (E) changes so as to increase the tail component on the high energy side, and as a result, N (E) also shifts to the high energy side as a whole.

It should be noted that the fact that the electrons do not receive strong scattering that relaxes to the thermal equilibrium state means that the RTO-P
This means that the energy loss in the PS layer 6, that is, the thermal loss is small, and it is considered that the efficiency of the emission electron current Ie is high and electrons can be stably emitted. FIG. 8 is a graph showing the time-dependent changes of the diode current Ips and the emission electron current Ie of the field emission electron source 10 according to the present embodiment. The horizontal axis represents time, and the vertical axis represents current density. A indicates the diode current Ips, and B in the figure indicates the emission electron current Ie. FIG. 8 shows the result when the DC voltage Vps is fixed at 15 V and the DC voltage Vc is fixed at 100 V. As can be seen from FIG. 8, in the field emission type electron source 10 of the present embodiment, neither the diode current Ips nor the emission electron current Ie shows a popping phenomenon.
A substantially constant diode current Ips and emission electron current Ie can be maintained over time. This is RTO
In the PPS layer 6, the surface of each grain is porous, and the crystal state is maintained in the central portion of each grain, and the heat generated by applying a voltage is conducted to the portion where the crystal state is maintained and is released to the outside. It is presumed that the temperature rise is suppressed. Such a stable characteristic of the emission electron current Ie with little change with time is a characteristic that cannot be obtained by a conventional MIM method or a field emission electron source realized by making the surface of a single crystal silicon substrate porous. And the characteristics obtained by employing the structure of the present invention.

Next, the field emission type electron source 10 of this embodiment
The dependence of the emission electron current Ie on the degree of vacuum will be described.
FIG. 9 shows a case in which the periphery of the field emission type electron source 10 of this embodiment is Ar.
The change of the diode current Ips and the emission electron current Ie when the degree of vacuum is changed as a gas atmosphere is shown. In FIG. 9, the horizontal axis represents the degree of vacuum and the vertical axis represents the current density.
Indicates the diode current Ips, and b (●) in the figure indicates the emission electron current Ie. From FIG. 9, when the degree of vacuum is in the range of about 10 ⁻⁵ Pa to about 1 Pa, a substantially constant emission electron current Ie is obtained.
It turns out that the degree of vacuum dependence of the emission electron current Ie is small. That is, since the field emission electron source 10 of the present embodiment has a small dependence of the electron emission characteristics on the degree of vacuum, even if the degree of vacuum changes somewhat, electrons can be stably and efficiently emitted (emitted). Good electron emission characteristics can be obtained even at a degree of vacuum, and there is no need to use the device in a high vacuum as in the prior art. Therefore, the cost of an apparatus using the field emission type electron source 10 can be reduced and handling can be facilitated.

In this embodiment, the n-type silicon substrate 1 ((100) substrate having a resistivity of about 0.1 Ωcm) is used as the conductive substrate, but the conductive substrate is limited to the n-type silicon substrate. Instead, for example, a transparent conductive thin film (for example, ITO: Indium) is formed on a metal substrate or a glass substrate.
A substrate on which a conductive film such as Tin Oxide or Platinum or Chromium is formed may be used, and the area and cost can be reduced as compared with the case where a semiconductor substrate such as an n-type silicon substrate is used.

(Embodiment 2) The basic configuration of the field emission type electron source 10 of this embodiment is substantially the same as that of Embodiment 1 shown in FIG. 1, so that the illustration is omitted, and the manufacturing method is shown in FIGS. 10 and 11. I will explain while. In this embodiment, as shown in FIG. 11C, the porous polysilicon layer 6 of the first embodiment is formed by alternately stacking a high-porosity polysilicon layer 6b and a low-porosity polysilicon layer 6a. The difference is that they are constituted by layers. In this embodiment, as in the first embodiment, an n-type silicon substrate 1 (a (100) substrate having a resistivity of about 0.1 Ωcm) is used as the conductive substrate.
Is used.

First, after forming an ohmic electrode 2 on the back surface of the n-type silicon substrate 1, a non-doped polysilicon layer 3 having a thickness of about 1.5 μm is formed on the surface of the n-type silicon substrate 1 as shown in FIG. A structure as shown in FIG.

Next, a platinum electrode (not shown) was used as a negative electrode, an n-type silicon substrate 1 (an ohmic electrode) was used, using an electrolytic solution consisting of a mixture of a 55 wt% aqueous solution of hydrogen fluoride and ethanol in a ratio of about 1: 1. Using the electrode 2) as a positive electrode, anodization is performed at a constant current while irradiating the polysilicon layer 3 with light. Here, the anodic oxidation treatment was performed in the following procedure.
As a condition of the anodizing treatment, the current density was set to 2.5 mA / c.
The first condition in which the anodizing time is 4 seconds and the constant m ^{2 is} constant, and the second condition in which the current density is 20 mA / cm ² and the anodizing time is 5 seconds are set. Anodizing treatment and anodizing treatment under the second condition were alternately repeated three times. However, during the anodization, the surface was irradiated with light by a 500 W tungsten lamp. Here, when the anodic oxidation under the first condition is completed, a porous polysilicon layer 4a having low porosity (hereinafter, referred to as a PPS layer 4a) is formed on the surface side of the polysilicon layer 3 as shown in FIG.
A structure as shown in FIG. After that, when the anodic oxidation under the second condition is completed, the PPS is placed closer to the n-type silicon substrate 1 than the porous polysilicon layer 4a.
Porous polysilicon layer 4b having higher porosity than layer 4a
(Hereinafter, referred to as PPS layer 4b) is formed as shown in FIG.
The structure as shown in FIG. Thus, the first condition,
When the anodic oxidation under the second condition is completed three times,
FIG. 1 in which PPS layers 4a and PPS layers 4b are alternately stacked
The structure shown in FIG. 1 (a) is obtained. In the present embodiment, the thickness of the porous polysilicon layer having a laminated structure of the PPS layer 4a and the PPS layer 4b is approximately 1 μm. In this embodiment, a part of the polysilicon layer 3 is made porous, but the entire polysilicon layer 3 may be made porous.

Next, rapid thermal oxidation (RTO)
al Oxidation) technology for all PPS layers 4a, 4
By performing rapid thermal oxidation of b and the polysilicon layer 3, the structure shown in FIG. 11B is obtained. Here, FIG.
5B shows a polysilicon layer which has been rapidly thermally oxidized, and 6a and 6b show the porous polysilicon layers which have been rapidly thermally oxidized (hereinafter referred to as RTO-PPS layers 6a and 6b). The conditions for rapid thermal oxidation are as follows:
C. and the oxidation time was 1 hour. In the present embodiment,
Since the PPS layers 4a and 4b and the polysilicon layer 3 are oxidized by rapid thermal oxidation, the temperature can be raised to the oxidation temperature in a few seconds, which is a problem in an ordinary furnace tube type oxidation apparatus. Entrapment oxidation at the time can be suppressed.

Thereafter, a gold thin film 7 as a metal thin film is formed on the uppermost RTO-PPS layer 6a, for example, by vapor deposition, whereby the field emission type electron source 10 having the structure shown in FIG. 11C is obtained. Here, in the present embodiment, the gold thin film 7
Was about 10 nm, but this thickness is not particularly limited. The field emission type electron source 10 is a gold thin film 7.
Is a positive electrode (anode) of the electrode, and the ohmic electrode 2 is a negative electrode (cathode).

Hereinafter, the field emission type electron source 10 of this embodiment will be described.
Will be described.

The above-mentioned field emission type electron source 10 is introduced into a vacuum chamber (not shown), and the same as in the first embodiment, FIG.
The collector electrode 2 is located at a position facing the gold thin film 7 as shown in FIG.
1 (emission electron collecting electrode), the degree of vacuum in the vacuum chamber is set to about 5 × 10 ⁻⁵ Pa, and a DC voltage Vps is applied between the gold thin film 7 and the ohmic electrode 2. By applying a DC voltage Vc to the gold thin film 7, a diode current Ips flowing between the gold thin film 7 and the ohmic electrode 2, and electrons e ⁻ emitted from the field emission type electron source 10 through the gold thin film 7. (Note that a dashed line in FIG. 3 indicates a radiated electron flow.)
FIG. 12 shows the result of measurement of the emission electron current Ie flowing between the sample 1 and the gold thin film 7. Here, the gold thin film 7 applies a DC voltage Vps as a positive electrode to the ohmic electrode 2 (that is, the n-type silicon substrate 1), and the collector electrode 21 applies a DC voltage Vc to the gold thin film 7 as a positive electrode. I have.

The horizontal axis in FIG. 12 shows the value of the DC voltage Vps, and the vertical axis shows the current density. A (図) in FIG. 12 indicates the diode current Ips, and (b) in FIG. 12 indicates the emission electron current. Ie.
Note that the DC voltage Vc was kept constant at 100V.

As can be seen from FIG. 12, in the present embodiment, as in the first embodiment, the emission electron current Ie is observed only when the DC voltage Vps is positive, and as the value of the DC voltage Vps increases, the diode current Ips and the emission current Ie increase. Emitted electron current I
e also increased. For example, when the DC voltage Vps is 15 V, the current density of the diode current Ips is approximately 1 mA / cm.
^2. The current density of the emission electron current Ie is approximately 4 μA / cm ² , and the value of the emission electron current Ie is the field emission type realized by making the surface of the single crystal silicon substrate porous as described in the conventional example. This value is larger than that of an electron source (see JP-A-8-250766). For example, according to the Institute of Electronics, Information and Communication Engineers, ED96-141 and P41-46, when the DC voltage Vps is 15 V, the diode current Ips The current density is about 40 mA / cm ² and the emission electron current Ie is about 1 μA / cm ² ), indicating that the field emission electron source of this embodiment has a high electron emission efficiency.

FIG. 13 shows the data on the emission electron current Ie and the DC voltage Vps in Fowler-Nordhe.
The result of im (Fowler-Nordheim) plot is shown. From FIG. 13, since each data is on a straight line, it is inferred that this emission electron current Ie is a current due to the emission of electrons due to the quantum tunnel effect, as in the first embodiment.

FIG. 14 shows a field emission type electron source 1 of this embodiment.
0 is a graph showing the time-dependent changes of the diode current Ips and the emission electron current Ie of 0, wherein the horizontal axis represents time and the vertical axis represents current density.
In the figure, b indicates the emission electron current Ie. FIG.
4 indicates that the DC voltage Vps is constant at 21 V and the DC voltage Vc is 10
This is the result when 0 V is fixed. As can be seen from FIG. 14, also in the field emission type electron source 10 of the present embodiment,
As in the first embodiment, no popping phenomenon is observed in both the diode current Ips and the emission electron current Ie, and the diode current Ips and the emission electron current I
e can be maintained. Such an emission electron current Ie
The stable characteristics with little change over time are characteristics that cannot be obtained with the conventional MIM method or the field emission type electron source realized by making the surface of a single crystal silicon substrate porous, and the structure of the present invention is adopted. This is a characteristic obtained by performing

The anodic oxidation process may be performed under the following conditions. That is, FIG.
As shown in, in the course of increasing the current density anodic oxidation starts as 0 mA / cm ^2, the current density from 0 mA / cm @ 2 to 20 mA / cm ² for 20 seconds, the current density 2
A period of ^2.5 mA / cm ² for only seconds may be provided three times. However, it is a matter of course that the surface is irradiated with light by a 500 W tungsten lamp during the anodic oxidation. In this case, the porous polysilicon layer 4a having low porosity is formed during the period when the current density is set to ^2.5 mA / cm ² .

(Embodiment 3) The basic configuration of a field emission type electron source 10 of this embodiment is substantially the same as that of Embodiment 1 shown in FIG. 1, so that the illustration is omitted and the manufacturing method will be described with reference to FIG. I do. The present embodiment is characterized in that the porous polysilicon layer 6 in the first embodiment is a layer whose porosity continuously changes in the thickness direction. In this embodiment, as in the first embodiment, an n-type silicon substrate 1 (a (100) substrate having a resistivity of about 0.1 Ωcm) is used as the conductive substrate.

First, after forming an ohmic electrode 2 on the back surface of the n-type silicon substrate 1, a non-doped polysilicon layer 3 having a thickness of about 1.5 μm is formed on the surface of the n-type silicon substrate 1 as shown in FIG. A structure as shown in FIG.

Next, a platinum electrode (not shown) was used as a negative electrode, an n-type silicon substrate 1 (an ohmic electrode) was used using an electrolytic solution consisting of a mixture of a 55 wt% aqueous hydrogen fluoride solution and ethanol in a ratio of about 1: 1. Using the electrode 2) as a positive electrode, anodization is performed at a constant current while irradiating the polysilicon layer 3 with light. Here, the anodic oxidation treatment is performed by setting the current density to 0 mA.
/ Cm ² anodizing begins as continuously (gradually) the current density from 0 mA / cm ² with time until 20 mA / cm ² is increased. However, 500 during anodization
The surface was irradiated with light by a tungsten lamp of W. However, when the anodizing process is completed,
A porous polysilicon layer 4c (hereinafter referred to as a PPS layer 4c) having a high porosity on the side close to the n-type silicon substrate 1 and a low porosity near the surface and having a continuously changed porosity in the thickness direction is formed. A structure as shown in FIG. 16B is obtained. In this embodiment, the thickness of the PPS layer 4c is approximately 1
μm. In this embodiment, a part of the polysilicon layer 3 is made porous, but the entire polysilicon layer 3 may be made porous.

Next, the PPS layer 4 is formed by a rapid thermal oxidation technique.
c and the polysilicon layer 3 are subjected to rapid thermal oxidation (the conditions of rapid thermal oxidation are an oxidation temperature of 900 ° C. and an oxidation time of 1
Then, the field emission electron source 10 having the structure shown in FIG. 16C is obtained by forming the metal thin film 7 as the gold thin film by, for example, vapor deposition. Here, in the present embodiment, the thickness of the gold thin film 7 is set to approximately 10 nm, but this thickness is not particularly limited. The field emission electron source 10 has a diode in which the gold 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 FIG. 16C, reference numeral 5 denotes a polysilicon layer subjected to rapid thermal oxidation, and reference numeral 6 denotes PPS subjected to rapid thermal oxidation.
5 shows a layer 4c (RTO-PPS layer 6).

In the present embodiment, the porosity is changed by gradually increasing the current density in the anodic oxidation treatment. However, the porosity may be changed by gradually decreasing the current density. In the latter case, the side near the n-type silicon substrate 1 has low porosity and the side near the surface has high porosity.

(Embodiment 4) FIG. 17 shows a schematic configuration diagram of a flat light emitting device using the field emission electron source 10 of Embodiment 1. The same components as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted. Here, the field emission electron source 10 of the second or third embodiment may be used as the field emission electron source 10.

The planar light emitting device of the present embodiment includes a field emission type electron source 10 and a transparent electrode 31 disposed to face the gold thin film 7 of the field emission type electron source 10. A phosphor 32 that emits visible light by an electron beam emitted from the source 10 is applied. In addition, the transparent electrode 3
Numeral 1 is applied and formed on a transparent plate 33 such as a glass substrate.
Here, the transparent plate 33 on which the transparent electrode 31 and the phosphor 32 are formed is integrated with the field emission type electron source 10 via the spacer 34, and the transparent plate 33, the spacer 34 and the field emission type electron source 10 The enclosed inner space has a predetermined degree of vacuum. Therefore, by emitting electrons from the field emission type electron source 10, the phosphor 32 can emit light, and the emission of the phosphor 32 is emitted by the transparent electrode 31 and the transparent plate 3.
3 can be displayed externally.

In the flat light emitting device of this embodiment, the field emission type electron is applied while the transparent electrode 31 is used as a positive electrode with respect to the gold thin film 7 and a DC voltage Vc of 1 kV is applied between the transparent electrode 31 and the gold thin film 7. When a DC voltage Vps of about 15 V is applied between the gold thin film 7 of the source 10 and the ohmic electrode 2 to emit (emit) electrons, the area (size) of the gold thin film 7 is increased.
A fluorescent pattern corresponding to was obtained. This indicates that the density of the emission electron current Ie emitted from the field emission electron source 10 is substantially uniform in the plane of the gold thin film 7 and that the emitted electrons e ⁻ are substantially perpendicular to the gold thin film 7. Radiated,
It is a schematic evidence showing that are parallel without or narrowed or spread the flow ^- electron e. Therefore,
In the present embodiment, since the electrons e ⁻ are radiated almost uniformly in the substantially vertical direction in the plane of the gold thin film 7, there is no need to provide a focusing electrode used in the conventional flat light emitting device, and the structure becomes simpler. Cost reduction becomes possible. In addition, since popping does not occur when electrons are emitted from the field emission electron source 10, display unevenness can be reduced.

(Embodiment 5) FIG. 18 is a schematic configuration diagram of an electron source section when the field emission electron source 10 according to any one of Embodiments 1 to 3 is used for a display device. In the present embodiment, as shown in FIG. 18, the field emission electron sources 10 according to any one of Embodiments 1 to 3 are configured in a matrix (array), and each field emission electron source 10 is X for each pixel
The DC voltage Vps described above (described in the first embodiment) applied to each of the field emission electron sources 10 is turned on and off by the matrix control circuit 41 and the Y matrix control circuit 42, respectively. That is, in the present embodiment, the field emission electron source 10 to which the DC voltage Vps is applied is selected by the X matrix control circuit 41 and the Y matrix control circuit 42.
Electrons are emitted only from the selected field emission electron source 10.

Although not shown, in the display device of the present embodiment, similarly to the fourth embodiment, the display device is opposed to the electron source (that is, opposed to the gold thin film 7 of the field emission type electron source 10). ) A transparent electrode is provided, and a phosphor that emits visible light by an electron beam emitted from the field emission electron source 10 is applied to the transparent electrode. The transparent electrode is formed by coating on a transparent plate such as a glass substrate.

As described above, the electrons emitted from the field emission type electron source 10 are emitted almost uniformly in the plane of the gold thin film 7 from the gold thin film 7 in a substantially vertical direction, and the electron flows are substantially parallel. Therefore, in the display device of the present embodiment, only the phosphor portion facing the field emission electron source 10 can emit light. Therefore, it is not necessary to provide a complicated shadow mask as in the related art, and a high-definition display device can be realized.

(Embodiment 6) FIG. 19 is a schematic configuration diagram of a solid-state vacuum device using the field emission electron source 10 described in Embodiment 1. The same components as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted. The structure of the second or third embodiment may be adopted as the field emission electron source 10.

The solid-state vacuum device of this embodiment is of a triode type, in which the field emission type electron source 10 is used as a cathode, and the anode electrode 51 (anode) faces the gold thin film 7 of the field emission type electron source 10. Are arranged, and a mesh grid 52 is provided between the anode electrode 51 and the cathode. The anode electrode 51, the grid 52, and the cathode are vacuum-sealed by sealing materials 53 and 54. In this embodiment, a vacuum container is constituted by the sealing members 53 and 54 and the conductive substrate made of the n-type silicon substrate 1.

In the solid-state vacuum device of the present embodiment, when the above-described DC voltage Vps is applied to the field emission type electron source 10, electrons are emitted from the field emission type electron source 10, ie, the cathode, and the anode electrode 51 and the gold thin film 7, the anode current Va flows between the anode 51 and the cathode. The magnitude of the anode current Ia can be controlled by changing the value of the DC voltage Vg applied between the grid 52 and the ohmic electrode 2 using the grid 52 as a negative electrode.

A conventional vacuum device mainly uses a cathode using thermionic emission. However, if the field emission type electron source of the present invention is used, a solid-state vacuum device having a long life with a cold cathode can be realized.

In this embodiment, a triode-type solid vacuum device has been described. However, a triode-type solid vacuum device may of course be used.

[0071]

According to the first aspect of the present invention, there is provided a conductive substrate, a porous polysilicon layer formed on one surface side of the conductive substrate and having an oxidized nanometer structure, and the porous polysilicon layer. A metal thin film formed on the layer, and radiating an electron beam through the metal thin film by applying a voltage with the metal thin film as a positive electrode to the conductive substrate.
The porous polysilicon layer is formed on the surface of each grain.
Is made porous and the crystalline state is maintained at the center of each grain.
The heat generated by the application of the voltage
Conducted through the part where the above crystalline state is maintained and released to the outside
As a result, the temperature rise is suppressed and the dependence of the electron emission characteristics on the degree of vacuum is small, and a popping phenomenon does not occur at the time of electron emission, so that electrons can be emitted stably and with high efficiency. In addition to a semiconductor substrate such as a single-crystal silicon substrate, a substrate formed with a conductive film on a glass substrate or the like can be used. There is an effect that the area of the electron source can be increased and the cost can be reduced as compared with the Spindt-type electrode.

A second aspect of the present invention is a conductive substrate, a porous polysilicon layer formed on one surface side of the conductive substrate and having a structure in units of nanometers, and a porous polysilicon layer on the porous polysilicon layer. A metal thin film formed on the conductive substrate, and applying a voltage with the metal thin film as a positive electrode to the conductive substrate to emit an electron beam through the metal thin film.
The porous polysilicon layer is formed on the surface of each grain.
Is made porous and the crystalline state is maintained at the center of each grain.
The heat generated by the application of the voltage
Conducted through the part where the above crystalline state is maintained and released to the outside
As a result, the temperature rise is suppressed and the dependence of the electron emission characteristics on the degree of vacuum is small, and a popping phenomenon does not occur at the time of electron emission, so that electrons can be emitted stably and with high efficiency. In addition to a semiconductor substrate such as a single-crystal silicon substrate, a substrate formed with a conductive film on a glass substrate or the like can be used. There is an effect that the area of the electron source can be increased and the cost can be reduced as compared with the Spindt-type electrode.

The invention of claim 6 is the invention of claims 1 to 5
In the above invention, since the polysilicon layer is a non-doped polysilicon layer, the oxidized or nitrided porous polysilicon layer becomes semi-insulating, and by applying the voltage, the porous polysilicon layer becomes strong. As an electric field, the electrons injected from the conductive substrate side into the porous polysilicon layer drift and reach the surface of the porous polysilicon layer, and the electrons are tunneled through the metal thin film as hot electrons. Since the light is emitted, electrons can be emitted more efficiently and stably than in the case where the polysilicon layer is doped, and there is an effect that manufacturing is easy because doping is unnecessary.

The invention of claim 7 is the invention of claims 1 to 6
In the invention of the above, since the conductive substrate is formed of a substrate having a conductive thin film formed on one surface, the area and cost can be reduced as compared with the case where a semiconductor substrate such as a single crystal silicon substrate is used as the conductive substrate. There is an effect that it becomes possible.

According to an eighth aspect of the present invention, there is provided the method for manufacturing a field emission type electron source according to the first aspect, wherein a polysilicon layer is formed on a conductive substrate, and the polysilicon layer is made porous. The oxidized polysilicon layer is oxidized, and an electrode made of a metal thin film is formed on the oxidized porous polysilicon layer, eliminating the need for complicated structures and manufacturing processes like conventional Spindt-type electrodes. It is possible to provide a low-cost field-emission electron source capable of stably and efficiently emitting electrons by a simple manufacturing process, and to provide a large-area field-emission electron source. is there.

According to a ninth aspect of the present invention, there is provided the method for manufacturing a field emission type electron source according to the second aspect, wherein a polysilicon layer is formed on a conductive substrate, and the polysilicon layer is made porous. Nitrided polysilicon layer, and an electrode made of a metal thin film is formed on the nitrided porous polysilicon layer, eliminating the need for complicated structures and manufacturing processes like conventional Spindt-type electrodes. It is possible to provide a low-cost field-emission electron source capable of stably and efficiently emitting electrons by a simple manufacturing process, and to provide a large-area field-emission electron source. is there.

According to a twelfth aspect of the present invention, there is provided the field emission type electron source according to any one of the first to seventh aspects, and a transparent electrode disposed to face the metal thin film, wherein visible light is generated by the electron beam. Since the phosphor that emits light is provided on the transparent electrode, the emission angle of the electrons emitted from the field emission electron source is aligned in a direction substantially perpendicular to the surface of the metal thin film, so it is necessary to provide a focusing electrode. Therefore, there is an effect that the structure can be simplified and a thin planar light emitting device can be realized.

According to a thirteenth aspect of the present invention, the field emission type electron source according to any one of the first to seventh aspects is configured in a matrix, and the voltage applied to each field emission type electron source is controlled. Means, and a transparent electrode disposed opposite to the metal thin film, wherein a phosphor which emits visible light by the electron beam is provided on the transparent electrode. Since the angle of emission of electrons emitted from the source is substantially perpendicular to the surface of the metal thin film, there is no need to provide a complicated shadow mask or electron focusing lens, and a high-definition display device can be realized. effective.

The invention of claim 14 provides at least claim 1
Since the field emission type electron source according to any one of claims 7 to 7 and the anode are arranged in a vacuum vessel, the field emission type electron source constitutes a cold cathode, so that conventional thermionic emission is used. It is not necessary to provide a heating means unlike a solid-state vacuum device having a heated hot cathode, which makes it possible to reduce the size and suppress evaporation and deterioration of the cathode material, thereby realizing a long-life solid-state vacuum device. There is an effect that can be.

[Brief description of the drawings]

FIG. 1 is a cross-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 an explanatory diagram of a principle of measuring emitted electrons according to the first embodiment.

FIG. 4 is a voltage-current characteristic diagram of the above.

FIG. 5 shows the data of FIG. 4 as Fowler-Nordhei.
It is a graph which plotted m.

FIG. 6 is a band diagram for explaining an electron emission mechanism of the above.

FIG. 7 is an explanatory diagram of an energy distribution of emitted electrons in Embodiment 1;

FIG. 8 is a graph showing a temporal change of the current in the above.

FIG. 9 is a graph showing the degree of vacuum dependency of the above current.

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

FIG. 11 is a main process sectional view for explaining the manufacturing process of the above.

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

FIG. 13 shows the data of FIG. 12 as Fowler-Nordh
It is the graph which carried out eim plot.

FIG. 14 is a graph showing a temporal change of the current in the above.

FIG. 15 is an explanatory diagram of an anodic oxidation treatment of another configuration example of the embodiment.

FIG. 16 is a main process sectional view for illustrating the manufacturing process of the third embodiment.

FIG. 17 is a schematic configuration diagram showing a fourth embodiment.

FIG. 18 is a schematic configuration diagram of a main part showing a fifth embodiment.

FIG. 19 is a schematic configuration diagram showing a sixth embodiment.

[Explanation of symbols]

 Reference Signs List 1 n-type silicon substrate 2 ohmic electrode 5 rapidly thermally oxidized polysilicon layer 6 rapidly thermally oxidized porous polysilicon layer 7 gold thin film 10 field emission electron source

──────────────────────────────────────────────────続 き Continuation of the front page (51) Int.Cl. ⁶ Identification symbol FI H01J31 / 12 H01J31 / 12C (56) References JP-A-9-259795 (JP, A) JP-A-10-269932 ( JP, A) Xia Sheng at al. , "Properties of Poor Silicon EL Diodes as Surface-Emitting Cold Cathode (IV)", Proceedings of the 44th Joint Lecture on Applied Physics, March 1997, 29p-Y12 (58). Cl. ^6, DB name) H01J 1/30 H01J 9/02 H01J 19/24 H01J 21/10 H01J 29/04 H01J 31/12 JICST file (JOIS)

Claims (14)

(57) [Claims] 1. A conductive substrate, a porous polysilicon layer formed on one surface side of the conductive substrate and having an oxidized nanometer structure, and a metal formed on the porous polysilicon layer. A thin film, which emits an electron beam through the metal thin film by applying a voltage to the conductive substrate as a positive electrode with respect to the conductive substrate.
The silicon layer is made porous by making the surface of each grain porous.
A field emission type electron source characterized in that a crystalline state is maintained in the central part of the rain . 2. A conductive substrate, a porous polysilicon layer formed on one surface side of the conductive substrate and having a structure in units of nanometers, and a metal formed on the porous polysilicon layer. A thin film that emits an electron beam through the metal thin film by applying a voltage to the conductive substrate as a positive electrode with respect to the conductive substrate.
The silicon layer is made porous by making the surface of each grain porous.
A field emission type electron source characterized in that a crystalline state is maintained in the central part of the rain . 3. The porous polysilicon layer according to claim 1, wherein a high-porosity polysilicon layer and a low-porosity polysilicon layer are alternately stacked.
Or the field emission type electron source according to claim 2. 4. The field emission type electron source according to claim 1, wherein the porous polysilicon layer is a layer whose porosity continuously changes in a thickness direction. 5. The porous polysilicon layer according to claim 1, wherein the porosity is continuously changed in the thickness direction such that the porosity on the conductive substrate side is higher than that on the surface side. The field emission type electron source according to claim 1. 6. The field emission electron source according to claim 1, wherein the polysilicon layer is a non-doped polysilicon layer. 7. The field emission electron source according to claim 1, wherein the conductive substrate comprises a substrate having a conductive thin film formed on one surface. 8. The method according to claim 1, wherein a polysilicon layer is formed on the conductive substrate, the polysilicon layer is made porous, and the porous polysilicon layer is made. A field emission type electron source characterized by forming an electrode made of a metal thin film on an oxidized porous polysilicon layer. 9. The method for manufacturing a field emission type electron source according to claim 2, wherein a polysilicon layer is formed on the conductive substrate, the polysilicon layer is made porous, and the porous polysilicon layer is made. And forming an electrode made of a metal thin film on the nitrided porous polysilicon layer. 10. The method of manufacturing a semiconductor device according to claim 10, wherein the step of changing the porosity of the polysilicon layer includes changing the porosity of the polysilicon layer so that the high porosity polysilicon layer and the low porosity polysilicon layer are alternately stacked. The method for manufacturing a field emission electron source according to claim 8 or 9, wherein: 11. When making the polysilicon layer porous, conditions for making the polysilicon layer porous are set such that the porosity on the conductive substrate side is higher than the surface side and the porosity changes continuously in the thickness direction. The method for manufacturing a field emission type electron source according to claim 8, wherein the method is changed. 12. A phosphor, comprising: the field-emission electron source according to claim 1; and a transparent electrode disposed to face the metal thin film, wherein the phosphor emits visible light by the electron beam. Is provided on the transparent electrode. 13. A field emission type electron source according to claim 1, wherein said field emission type electron source is arranged in a matrix, and said voltage is applied to each of said field emission type electron sources. A display device comprising: a transparent electrode disposed to face a thin film; and a phosphor that emits visible light by the electron beam, provided on the transparent electrode. 14. A solid-state vacuum device comprising at least the field emission electron source according to claim 1 and an anode disposed in a vacuum vessel.