JP3264483B2 - Electron emitting device and method of manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electron-emitting device that emits an electron beam, and more particularly to an electron-emitting device formed using a diamond layer and a method of manufacturing the same.

[0002]

2. Description of the Related Art A conventional electron-emitting device uses a hot cathode which draws electrons by heating a material such as tungsten (W) to a high temperature. In recent years, as an electron beam source replacing such an electron gun, a microelectron emitting device of a cold cathode type has attracted attention. Such types of electron-emitting devices include:
Generally, a field emission type and an avalanche amplification type using a pn and Schottky junction have been reported.

A field emission type electron-emitting device is a cone-shaped emitter made of a refractory metal such as silicon (Si) or molybdenum (Mo) by applying a voltage to an extraction electrode and applying an electric field. It emits electrons from the substrate, and has features such as miniaturization can be achieved by using microfabrication technology.

On the other hand, an avalanche amplification type using a semiconductor material emits electrons from an emitter by emitting avalanche amplification by applying a reverse bias voltage to a pn and Schottky junction to emit electrons from an emitter. It is.

[0005] The characteristics required as a material of such an electron-emitting device are 1) that electrons are easily emitted in a relatively small electric field, that is, the electron affinity of the substance is small, and 2) stable electron emission characteristics. In order to maintain, the surface of the emitter section is chemically stable, and 3) the abrasion resistance and the heat resistance are excellent.

In view of the prior art from such a point of view, the field emission type element has a large dependence of the emission current on the shape of the emitter section, making it very difficult to manufacture and control the field emission element, and to reduce the surface of the material used. There were issues in terms of stability. Also in this scheme, each element is a point electron emission source,
It has been difficult to obtain a planar electron emission flow.

In the avalanche amplification type, since it is generally necessary to apply a very large amount of current to the element, heat is generated in the element, which causes unstable electron emission characteristics and shortens the life of the element. There was a problem. In the avalanche amplification type, the work function amount of the electron emission portion is reduced by providing a cesium layer or the like on the surface of the emitter, but a material having a small work function such as cesium has a chemically unstable surface state. There is also a problem that it is not stable, that is, the electron emission characteristics are not stable. As described above, the materials and structures used so far do not sufficiently satisfy the characteristics required for the electron-emitting device.

On the other hand, diamond is a semiconductor material having a wide bandgap (5.5 eV), and its characteristics are high hardness, abrasion resistance, high thermal conductivity, and chemical inertness. Very suitable as a material. By controlling the surface state of diamond, the energy level at the conduction band edge can be higher than the energy level of vacuum, that is, diamond can be in a state of negative electron affinity. That is, there is an advantage that if electrons are injected into the conduction band of the diamond layer, electrons can be easily emitted. In addition, diamonds
In general, it can be easily formed by a gas phase synthesis method using carbon-based gas species and hydrogen gas as raw material gases, and has an advantage in terms of manufacturing. However, it is not easy to supply electrons to the conduction band of diamond simply by bringing the electrode into contact with the diamond layer because the energy bands of the conduction band of metal and diamond are greatly different. The method and structure for efficiently supplying electrons to the conduction band of diamond have not been studied in detail, and an electron-emitting device that supplies and emits electrons to the conduction band of diamond has not been realized.

[0009]

SUMMARY OF THE INVENTION An object of the present invention is to provide an electron-emitting device which efficiently emits an electron beam in order to solve the above-mentioned problems in the prior art. Also one
An object of the present invention is to provide an electron-emitting device that easily emits an electron beam by forming a structure sandwiching at least an electron supply layer including an insulator layer and a diamond layer with a pair of electrode layers .

[0010]

In order to achieve the above object, an electron-emitting device according to the present invention is an electron-emitting device formed using a diamond layer, comprising a first electrode layer and a second electrode layer.
Of the two electrode layers, at least
An electron supply layer including an insulator layer and a diamond layer are sandwiched.
The first electrode layer and the
Supplying electrons to the diamond layer via a supply layer
It is characterized by.

In the above-mentioned electron-emitting device, an M - I - S - S- M (met) includes an electrode layer pair made of a metal, an electron supply layer made of an insulator layer, and a diamond layer including a p-type diamond layer.
al-insulator-semiconductor-metal) structure,
It is preferable that a positive voltage be applied to the second electrode layer having the MISM structure to supply electrons to the p-type diamond layer.

In the above-mentioned electron-emitting device, the electrode layer
Pair is a metal, comprises a semiconductor layer of the semiconductor layer and the i-type electron supply layer is n-type, M-N-I-P -M diamond layer comprises a p-type diamond layer (metal-n layer-insulat
or M-N-I-P-
It is preferable to apply a positive voltage to the second electrode layer having the M structure.

In the above-mentioned electron-emitting device, the thickness of the diamond layer is preferably 5 μm or less. More preferably, the thickness of the diamond layer is 0.05 μm or more.
1 μm or less.

Preferably, the diamond layer contains at least a p-type diamond layer. Also, p
The electrical resistivity of the diamond layer of the mold is preferably 1 × 10 ⁴ Ω · cm or less. More preferably, the electrical resistivity of the p-type diamond layer is 1 × 10 ⁻² Ω · cm or more and 1 × 10 ² Ω.
・ It is less than cm.

Next, a method for manufacturing an electron-emitting device according to the present invention is as follows.
A continuous film-like diamond layer is formed on a substrate material by a vapor phase synthesis method.

In the above method, the thickness of the diamond layer is preferably 1 μm or less, and more preferably the thickness of the diamond layer is 0.05 μm or more and 1 μm or less.

Further, in the above method, after a diamond layer is formed on a substrate material by a vapor phase synthesis method,
It is preferable that the diamond layer is etched to a predetermined thickness or less from at least one surface selected from the surface of the diamond layer on the substrate material side and the surface of the diamond layer on the surface side. In the above, the predetermined thickness is preferably 0.05 μm or more and 1 μm or less.

Next, the method for manufacturing an electron-emitting device of the present invention is as follows.
A first electrode layer, disposed opposite to the first electrode layer;
A second electrode layer, the first electrode layer, and the second electrode layer
And an electron supply layer disposed between the
Electron-emitting device having a diamond layer provided by
Manufacturing method, which is connected on a substrate material by a vapor phase synthesis method.
Forming a diamond layer in the form of a continuous film;
The surface of the diamond layer on the substrate material side, and the diamond layer
From at least one surface selected from the surface side predetermined surface
Etching the diamond layer to a thickness below the thickness
After the etching step, a part is formed as an electron supply layer.
The surface of the diamond layer used on the substrate material side and the surface side
A step of forming the first and second electrode layers in a predetermined region.
It is characterized by including at least. In the above method,
Before the step of forming the first and second electrode layers, it is preferable to irradiate a predetermined region of the diamond layer with vacuum ultraviolet light having a wavelength of 200 nm or less, more preferably 100 nm or more and 200 nm or less.

In the above method, the diamond layer
And then further etching the die
It is preferable to expose a predetermined region of the almond layer to plasma obtained by subjecting a gas containing hydrogen to electric discharge decomposition.

In the above method, it is preferable that, after forming the diamond layer, a predetermined region of the diamond layer is further exposed to plasma obtained by discharge-decomposing a gas containing oxygen.

In the above method, the diamond layer
After etching, it is preferable to further expose the heated diamond layer to a gas containing hydrogen.

In the above method, after forming the diamond layer, it is preferable to further expose the heated diamond layer to a gas containing oxygen.

[0023]

DETAILED DESCRIPTION OF THE INVENTION As described in the background section, diamond has a negative electron affinity and is suitable as an electron-emitting device material. It is necessary to supply electrons to the conduction band of diamond. Also, in order to easily emit electrons, it is necessary to control the surface state of the emitter. That is, in order to form a highly efficient electron-emitting device using a diamond layer, (1) a method of supplying electrons to the emitter region and (2) a method of controlling the surface of the emitter section are important.

According to the embodiment of the present invention, there is provided an electron-emitting device formed using a diamond layer, comprising :
Since the electrode has a laminated structure including the electrode layer pair , the electron supply layer including at least the insulator layer, and the diamond layer, the following effects are exhibited.

FIG. 1 is a schematic diagram of an element showing the present embodiment. By applying a bias between the first and second electrode layers 11a and 11b, an electric field can be easily applied to the sandwiched electron supply layer 12 and diamond layer 13. At this time, an appropriate electric field can be applied to the electron supply layer 12 by controlling the magnitude of the applied bias. As a result, electrons can be easily injected from the first electrode layer 11a to the electron supply layer 12 and further from the electron supply layer 12 to the diamond layer 13, and by controlling the state of the surface 14 of the diamond layer. Since a state of negative electron affinity can be achieved, electrons can be efficiently extracted to the outside. The state of the surface 14 of the diamond layer having a negative electron affinity is not particularly limited, but can be easily realized by bonding hydrogen atoms to carbon atoms on the outermost surface of the diamond layer 13. The electron supply layer is not particularly limited, but an insulating diamond, an insulator layer, or the like is used.

In the case of such an embodiment, since an electric field only needs to be applied to the electron supply layer 12 to supply electrons to the diamond layer 13, it is not always necessary to contact the diamond layer 13 like the second electrode 11b in FIG. There is no need to provide them, and they may be installed in the space on the diamond layer side with an interval like the electrode 11c.
In this embodiment, the following operation is exhibited. That is, when electrons are injected into the electron supply layer 12 from the first electrode layer 11a by any method, for example, a method such as tunneling injection, light excitation, or thermal excitation, electrons are supplied from the electron supply layer 12 to the conduction band of the diamond layer 13. You. In this way, the electrons supplied to the conduction band of diamond having a negative electron affinity are easily extracted from the diamond layer surface 14 to the outside. As a result, it is possible to efficiently obtain emitted electrons (indicated by arrow 15) with smaller energy than before.

In the above embodiment, the two electrodes 11
a, b at least electron supply layer 12 and diamond layer
Although 13 is sandwiched between the diamond layer and the electron supply layer, it is only necessary to apply an electric field to supply electrons to the diamond layer. Therefore, even if a voltage is applied only to the electron supply layer, the electron-emitting device of the present invention can be realized. In this case, the arrangement of the two electrode layers has a structure sandwiching only the electron supply layer. The diamond layer is formed on the same electron emission surface as the electrode in contact with the electron supply layer.

In the diamond layer 13 used in these embodiments, since the Fermi level exists near the valence band edge, a negative electron affinity state in which the conduction band edge level is higher than the vacuum level is remarkable. A p-type diamond layer is suitable and has a thickness and an electric resistivity of 5 μm or less and 1 × 10 ⁴ Ω · cm or less, more preferably 1 μm or less and 1 × 10 ² Ω · cm or less. The reason is that, when the film thickness is small as described above, electrons supplied from the electron supply layer 12 to the conduction band of the diamond layer 13 easily reach the surface 14 of the diamond layer and are extracted to the outside as emitted electrons 15 This is because, when the film thickness is large, the emission efficiency is lowered due to transition to the valence band or attraction to the electrode before reaching the surface. If the electric resistivity value is larger than the above value, the Fermi level of the diamond approaches the center of the forbidden band, and the negative electron affinity characteristic decreases. Further, when the electric resistivity value is high, the ratio of the electric field applied to the electron supply layer is relatively reduced, so that the electron supply efficiency is reduced.

The concentration of boron (B) atoms contained in the p-type diamond layer is 1 × 10 ¹⁶ / cm ³ or more.
× 10 ²⁰ pieces / cm ³ or less, more preferably 1 × 10 ¹⁷ pieces / cm ³
cm ³ or more. Such a value can be easily realized by controlling the conditions for forming the p-type diamond layer.
When the boron atom concentration is lower than the above, the device efficiency is reduced corresponding to the case where the electrical resistivity value of the diamond layer is large.

When the electron emission surface of the diamond layer is terminated with hydrogen, the electron emission surface has excellent negative electron affinity, and is coated with Cs, Ni, W, a-C (a is amorphous) or the like. Function as an electron-emitting device. The density of attached atoms is 1 × 10 ¹⁵ atoms
It is suitable that the concentration is not less than / cm ^{2 and not} more than 1 × 10 ¹⁷ atoms / cm ² . The surface of diamond terminated with hydrogen generally has conductivity, and this surface conductive layer is also effective as an electron emission surface of diamond.

The range of the bias applied between the electrodes also depends on the thickness and the electric resistance of the electron supply layer 12 and the diamond layer 13, but an electron emitting element operating at 0.1V or more and 100V or less can be realized.

According to another embodiment of the present invention,
An electron-emitting device formed using a diamond layer, which has a structure including at least an electrode layer, an electron supply layer, a diamond layer, and an insulator layer stacked in contact with the diamond layer. Therefore, the following operation can be achieved.

FIG. 2 is a schematic view of an element showing the present embodiment. By applying a bias between the two different electrode layers 21a and 21b, an electric field can be easily applied to the sandwiched electron supply layer 22 and diamond layer 23. At this time, an appropriate electric field can be applied to the electron supply layer 22 by controlling the magnitude of the applied bias. As a result, electrons can be easily injected from one electrode layer 21a to the electron supply layer 22 and further from the electron supply layer 22 to the diamond layer 23, and the other of the injected electrons is not taken out to the outside. The part flowing to the electrode 21b is an insulator layer
25, the electrons (arrows) can be efficiently generated from the surface 24 of the diamond layer having a negative electron affinity.
26) can be taken out.

The range of the applied bias between the two electrodes also depends on the thickness and the electric resistance of the electron supply layer 22 and the diamond layer 23 as described above. Electrons are emitted from the surface.

As the diamond layer used in the present invention, a p-type diamond layer is suitable as described above, and the desired characteristics are also the same.

As the insulator layer 25, one having a thickness and an electric resistivity that does not affect the electric field applied to the electron supply layer 22 and that interrupts a current to the electrode layer 21b is used. Are suitable. Specifically, the thickness is 1 μm or less, and 1
The resistivity is preferably from 10 ⁴ Ω · cm to 1 × 10 ¹² Ω · cm, and more preferably from 1 × 10 ⁸ Ω · cm or more. This is because, as the film thickness increases, the ratio of the electric field applied between the electrodes 21a and 21b to the insulator layer 25 increases, and the efficiency of supplying electrons from the electron supply layer decreases. The material and the like of the insulator layer 25 are not particularly limited, but an insulating diamond layer, a silicon dioxide layer, or the like is often used.

According to the preferred embodiment of the present invention in which the diamond layer includes at least a p-type diamond layer, it is suitable for an electron-emitting device for the above-described reasons. Further, in the embodiment of the present invention, the thickness and resistivity of the p-type diamond layer contained in the diamond layer is 0.05 μm or more and 5 μm or less and 1 × 10 ⁻² Ωcm or more and 1 × 10 ⁴ Ωcm or less,
More preferably, according to a preferred example of 1 μm or less and 1 × 10 ² Ω · cm or less, electron emission with lower energy becomes possible.

Further, according to the embodiment of the present invention, there is provided an electron-emitting device formed by using a diamond layer, comprising : a pair of electrode layers; an electron supply layer formed of an insulator such as an i-type diamond layer; M-I-S consisting of a diamond layer
By applying a positive voltage to the second electrode layer having the -M structure and supplying electrons to the p-type diamond layer via the electron supply layer, the following effects are exhibited. That is, a suitable positive electrode is formed on the second electrode layer of the MISM structure.
When a voltage is applied, electrons tunnel through an energy barrier existing at the metal / insulator layer interface from an electrode layer of metal or the like, and are efficiently injected into the p-type diamond layer, and the injected electrons are negative. Of the electron affinity state of
It can be easily released outside from the surface of the diamond layer of the mold.

FIG. 3 shows an embodiment of the electron-emitting device according to the present invention. In this embodiment, an i-type diamond layer is used as the electron supply layer (insulator layer) 33,
An energy barrier is formed at the interface with the electrode layer 32. On the i-type diamond layer, a p-type diamond layer 34 whose surface state is controlled to be in a negative electron affinity state is laminated. On a part of the surface of the p-type diamond layer 34, an electrode layer 35 for applying a bias to the element is formed.

FIG. 4 is a diagram schematically showing the state of the energy band of the embodiment. In FIG. 4, Metal indicates a metal electrode layer 32, and i-type and p-type indicate an electron supply layer (edge layer: i-type diamond layer) 33 and a p-type diamond layer 34, respectively. In addition, ε _C , ε _V , ε _F , and ε _Vac represent the conduction band edge, the valence band edge, the Fermi level, and the energy level of the vacuum level, respectively.

In the equilibrium state (applied bias: 0, FIG. 4A), although the surface of the p-type diamond layer 34 is in a negative electron affinity state, there is no electron serving as a minority carrier in the conduction band. Can not be released.
However, when an appropriate forward bias is applied (FIG. 4B), most of the bias is applied to the electron supply layer (insulator layer) 33, so that the band is bent as shown in FIG. The width of the energy barrier existing at the interface between the layers is reduced, and electrons are injected from the electrode layer 32 into the conduction band of the p-type diamond layer 34 by a tunneling phenomenon. The degree of this implantation depends on the energy at the electrode layer / insulator layer interface.
The electron supply layer (insulator layer) depends largely on the energy height (△ ε = εC−εF) or barrier width of the energy barrier.
By making 33 an appropriate thickness, it is possible to inject efficiently. The electrons injected into the p-type diamond layer 34 move to the emitter where the electrons are emitted due to diffusion or the like, and the surface of the p-type diamond layer 34 has a negative electron affinity (εV> εVac). Released to Electrode layer 32 having such appropriate thickness, the electron supply layer (insulating layer: i-type diamond layer) 33, a second electrode of a p-type diamond layer 34 M-I-S-M structure layer
By applying an appropriate positive voltage to the electrodes, emitted electrons can be stably and efficiently obtained. In the above description, an i-type diamond layer is used as the electron supply layer (insulator layer) 33. However, the present invention is not limited to this, and a silicon dioxide layer or the like may be used. Although the material used for the electrode layer 32 is not particularly limited, aluminum (Al) or tungsten (W) is generally used.

According to the preferred embodiment of the present invention, in which the thickness of the p-type diamond layer is 5 μm or less, preferably 1 μm or less, the injected electrons are efficiently supplied to the surface in the negative electron affinity state. It is possible to do. In the present invention, the concentration of boron atoms contained in the p-type diamond layer is not less than 1 × 10 ¹⁶ / cm ^{3 and not} less than 1 × 10 ²⁰ / cm ³
Hereinafter, according to a preferred example of desirably 1 × 10 ¹⁷ / cm ³ or more, a p-type diamond layer suitable for the element configuration can be obtained. In the present invention, the resistivity of the p-type diamond layer is 1 × 10 ⁻² Ω · cm or more and 1 × 10 ⁴ Ω · c
According to a preferred example of not more than m, more preferably not more than 1 × 10 ² Ω · cm, it is possible to suppress the loss due to resistance.

In the present invention, the electric resistivity of an i-type diamond layer used as an electron supply layer (insulator layer) is 1 × 10 ⁴ Ω · cm to 1 × 10 ¹² Ω · cm, preferably 1 × 10 ¹² Ω · cm. ⁸
According to a preferred example of Ω · cm or more, the applied bias can be efficiently applied to the high resistance region, so that injection of electrons by tunneling becomes easy.

FIG. 5 is a diagram showing an example of an electron-emitting device according to the reference example . In this example, an n-type diamond layer is formed on the electrode layer 52 as an electron supply layer 53 of an n-type semiconductor layer. On the n-type diamond layer 53,
P whose surface state is controlled to be in a negative electron affinity state
A diamond layer 54 of a mold is laminated. And the p
An electrode layer 55 for applying a bias to the element is formed on a part of the surface of the diamond pattern layer 54.

FIGS. 6A and 6B are views schematically showing the state of the energy band of the reference example . 6A and 6
Metal in B indicates a metal electrode layer 52, and n-type and p-type indicate an electron supply layer (n-type semiconductor layer: n-type diamond layer) 53 and a p-type diamond layer 54, respectively. In the equilibrium state (applied bias: 0, FIG. 6A), the p-type diamond layer 54 has a negative electron affinity state, but cannot emit electrons because there are no electrons in the conduction band.
However, in a state where an appropriate forward bias is applied (FIG. 6B), electrons are injected from the n-type semiconductor layer 53 (n-type diamond layer) into the conduction band of the p-type diamond layer 54. The electrons move to the emitter portion by diffusion or the like and are emitted to the outside from the p-type diamond layer 54. By applying a forward bias to the pn structure composed of the electrode layer 52 having an appropriate thickness, the n-type semiconductor layer 53 (n-type diamond layer), and the p-type diamond layer 54, the efficiency can be stabilized. Emitted electrons can be obtained well.

Further, according to the present invention, there is provided an electron-emitting device formed using a diamond layer, wherein
An electron supply layer comprising a semiconductor layer of an i-type and an i-type semiconductor layer;
M-N-I-P-M (met comprising a p-type diamond layer)
second electrodeposition al-n layer-insulator-p layer-metal) structure
To apply an appropriate positive voltage to the pole layer ,
Electrons are efficiently injected from the n-type semiconductor layer into the p-type diamond layer through the tunneling of the i-type semiconductor layer, and the injected electrons are applied to the surface of the p-type diamond layer in a negative electron affinity state. It can be more easily released to the outside. In this manner, an MNIPM (metal-n layer-insulator-p-metal) comprising an electrode layer having an appropriate thickness, an n-type semiconductor layer, an i-type semiconductor layer, and a p-type diamond layer.
By applying an appropriate positive voltage to the second electrode layer having a layer-metal structure , emitted electrons can be obtained stably and efficiently.

According to the preferred embodiment of the present invention, in which the thickness of the p-type diamond layer is 0.05 μm to 5 μm, preferably 1 μm or less, the injected electrons can be efficiently converted into a surface having a negative electron affinity state. It is possible to supply up to. In the present invention, the concentration of boron atoms contained in the p-type diamond layer is 1 × 10 ¹⁶ / cm ³ to 1 × 10 ²⁰ / c
According to a preferred example of m ³ , desirably 1 × 10 ¹⁷ / cm ³ or more, a p-type diamond layer suitable for the element structure can be obtained. Further, in the present invention, the resistivity of the p-type diamond layer and the n-type semiconductor layer is 1 × 10 ⁻² Ω · c
According to a preferred example of m to 1 × 10 ⁴ Ω · cm, desirably 1 × 10 ² Ω · cm or less, it is possible to suppress loss due to resistance.

In the present invention, the resistivity of the i-type semiconductor layer is 1 × 10 ⁴ Ω · cm to 1 × 10 ¹² Ω · cm or more, preferably 1 × 10 ¹² Ω · cm.
According to a preferred example of being not less than × 10 ⁸ Ω · cm, the applied bias can be efficiently applied to the high resistance region, so that injection of electrons by tunneling becomes easy.

Further, in the present invention, according to a preferred example in which the emitter portion from which electrons are emitted is the surface of the p-type diamond layer, a negative electron affinity state can be easily formed by controlling the surface state. Along with
Since the injected electrons can be efficiently extracted to the outside, an efficient electron-emitting device can be realized.

Further, according to the preferred embodiment of the present invention, in which the p-type diamond layer has a structure in which carbon atoms on the outermost surface are terminated by bonds to hydrogen atoms, the carbon atoms on the outermost surface can be easily converted to carbon atoms on the outermost surface. A structure bonded to hydrogen atoms can be formed, and p-type diamond can be in a very stable negative electron affinity state.

Further, in the present invention, the amount of hydrogen atoms bonded to carbon atoms on the outermost surface of the p-type diamond layer is
1 × 10 ¹⁵ pieces / cm ² to 1 × 10 ¹⁷ pieces / cm ² , preferably 2 × 10 ¹⁵ pieces / cm ²
According to a preferred example of being not less than cm ² , almost all outermost carbon atoms are bonded to hydrogen atoms, so that a more stable negative electron affinity state can be maintained.

According to a preferred embodiment of the present invention, in which the emitter from which electrons are emitted is near the interface between the p-type diamond layer and the layer in contact with the p-type diamond layer, the p-type layer conduction band Since the diffusion distance of the injected electrons becomes shorter, a more efficient electron-emitting device can be realized.

Further, according to the preferred embodiment of the present invention, in which a diamond surface conductive layer is used as the p-type diamond layer, the thickness can easily be reduced to 1 μm or less without a step of forming a new p-type diamond layer. Since a layer acting as a p-type diamond layer having a thickness can be obtained, an efficient electron-emitting device can be easily realized.

Further, according to the preferred embodiment of the present invention, the surface conductive layer of diamond has a structure in which carbon atoms on the outermost surface of the diamond layer are terminated by bonds to hydrogen atoms. Type diamond can be in a very stable negative electron affinity state.

Further, in the present invention, the amount of hydrogen atoms bonded to carbon atoms on the outermost surface of the diamond layer is 1 × 10
According to a preferred example of ¹⁵ pieces / cm ² to 1 × 10 ¹⁷ pieces / cm ² , desirably 2 × 10 ¹⁵ pieces / cm ² or more, since almost all the outermost surface carbon atoms are bonded to hydrogen atoms, A more stable negative electron affinity state can be maintained.

Further, in the present invention, according to a preferred example in which the thickness of the entire diamond layer is 0.05 to 5 μm or less, preferably 1 μm or less, electrons are efficiently emitted without losing electrons inside the diamond layer. It becomes possible.

Further, in the present invention, the structure of the electron-emitting device formed using the diamond layer has a width of 0.05 to 5 mm.
According to a preferred example of a thin line having a thickness of 1 μm or less, preferably 1 μm or less, electrons can be efficiently emitted without losing electrons inside the device, and electrons can be emitted linearly. Becomes

Further, according to the preferred embodiment of the present invention, in which the diamond layer is formed by a vapor phase synthesis method, it is possible to obtain a surface conductive layer on the surface of the diamond layer immediately after the growth without any treatment as a subsequent step. It becomes possible.

According to the structure of the method of the present invention as a method of forming the above structure, there is provided a method of manufacturing an electron-emitting device formed using a diamond layer, the method comprising the steps of: By providing a step of forming a continuous film-like diamond layer having a thickness of 1 μm or less, a high-efficiency electron-emitting device having a thin diamond layer can be easily formed.

Similarly, according to the method of the present invention, there is provided a method of manufacturing an electron-emitting device formed using a diamond layer, comprising the steps of: forming a diamond layer on a substrate material by vapor phase synthesis; Etching the diamond layer from the surface of the diamond layer on the substrate material side or the surface side of the diamond layer to a predetermined thickness or less, so that high-efficiency electron emission having a desired structure can be easily performed. An element can be formed.

As described above, in the electron-emitting device, it is very important to control the structure of the surface of the emitter. Generally, the method of forming a structure suitable as an emitter portion is not particularly limited, but it is easy to control the conductivity of the diamond surface, that is, to control the elements that bond to carbon atoms on the diamond surface. . As a specific example, diamond can be brought into a negative electron affinity state by using a hydrogen-terminated surface (conductive) as described above, and can be brought into a positive electron affinity state by using an oxygen-terminated surface (insulating). It can be. By arbitrarily controlling such a change in the surface state, the device configuration and manufacturing process of the high-efficiency electron-emitting device can be simplified.

Therefore, according to the method of the present invention, there is provided a method of manufacturing an electron-emitting device formed using a diamond layer, wherein the wavelength is 200 nm in a predetermined region of the diamond layer.
Since the method has the following step of irradiating vacuum ultraviolet light, it is possible to selectively remove elements bonded to the diamond surface and form new bonds. As a result, the electron affinity state of the diamond surface is positive (insulating)
And negative (conductivity).

According to the method of the present invention, there is provided a method of manufacturing an electron-emitting device formed by using a diamond layer.
A step of exposing a predetermined region of the etched diamond layer to plasma obtained by discharge-decomposing a gas containing at least hydrogen to selectively bond hydrogen atoms to the outermost carbon atoms of diamond. As a result, it is possible to easily form a region having a negative electron affinity state.

Further, according to the method of the present invention, there is provided a method for manufacturing an electron-emitting device formed using a diamond layer, comprising a step of exposing the heated diamond layer to a gas containing at least hydrogen. Therefore, a hydrogen atom can be selectively bonded to the outermost carbon atom of diamond, and as a result, a region in a negative electron affinity state can be easily formed.

Further, according to the method of the present invention, there is provided a method of manufacturing an electron-emitting device formed using a diamond layer, wherein a predetermined region of the diamond layer is obtained by discharge-decomposing at least a gas containing oxygen. Is characterized by having a step of exposing to oxygen, which makes it possible to selectively bind oxygen atoms to the outermost carbon atoms of diamond, thereby easily forming a region having a positive electron affinity state. Become.

According to the method of the present invention, there is provided a method for manufacturing an electron-emitting device formed using a diamond layer, comprising a step of exposing the heated diamond layer to a gas containing at least oxygen. Therefore, an oxygen atom can be selectively bonded to the outermost carbon atom of diamond, and as a result, a region having a positive electron affinity state can be easily formed.

As described above, by arbitrarily controlling the surface state of the diamond layer, the device configuration and manufacturing process of the high-efficiency electron-emitting device can be simplified.

It is also possible to form a planar electron-emitting device that emits electrons from the surface of a p-type diamond by forming the electron-emitting device including a diamond layer. In the conventional cone-shaped emitter, electron emission occurs only at the tip of the protruding portion. However, in the electron-emitting device including the diamond layer of the present invention, surface electron emission from an area of 1 to 10,000 square μm was confirmed. .

[0069]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples.

[0070]

First Embodiment First, an insulating diamond layer as an electron supply layer and a p-type diamond layer were formed on a 2 × 2 × 0.5 mm silicon (Si) substrate by a vapor phase synthesis method.
The method of vapor phase synthesis of the diamond layer is not particularly limited, but generally, a hydrocarbon gas such as methane, ethane, ethylene, acetylene, an organic compound such as alcohol or acetone, and carbon monoxide are used as a raw material gas. Is performed by using a carbon source diluted with hydrogen gas and applying energy to the raw material gas to decompose it. At that time, oxygen, water or the like can be added to the raw material gas as appropriate. In this embodiment, an insulating and p-type diamond layer is formed by a microplasma CVD method, which is a kind of a gas phase synthesis method. Microwave plasma CVD
The method is a method of forming a diamond by applying a microwave to a source gas to form diamond. As specific conditions, a carbon monoxide gas diluted to about 1 to 10 vol% with hydrogen was used as a source gas. At the time of p-type conversion, diborane gas was added to the source gas. The reaction temperature and pressure are 800-900C and 25-40 Torr, respectively. The film thicknesses of the formed insulating and p-type diamond layers were 2 μm and 0.5 μm, respectively. The p-type film was confirmed to contain 1 × 10 ¹⁸ boron atoms / cm ³ by secondary ion mass spectrometry.
× 10 ² Ω · cm or less. Hydrogen is bonded to the outermost surface of the p-type diamond layer obtained by the vapor phase synthesis, and as a result of evaluating the electron affinity state of the p-type diamond surface by irradiation with ultraviolet light, it is found that the electron affinity state is negative. all right.

Then, a part of the Si substrate was removed with a nitric acid-based etchant to form a hole, and the surface in contact with the substrate, that is,
An aluminum (Al) electrode was formed on the insulating diamond layer by vacuum evaporation. Further, a gold / titanium (Au / Ti) electrode was formed on a part of the p-type diamond layer by electron beam evaporation. As a result, a structure having an insulating (electron supply layer) and a p-type diamond layer sandwiched between two electrode layers as shown in FIG. 1 was produced.

The electron-emitting device manufactured by the above method was placed in a vacuum of about 10 ⁻⁹ Torr, and a positive voltage was applied to the Al electrode side up to about 100 V. Was confirmed to have been released. The emission current ratio (emission efficiency) is about 0.1 to 10%,
It was confirmed that electrons were emitted more efficiently than before.

Similar results were obtained when the p-type diamond layer was formed under other forming conditions, when the substrate material was changed, and when the electrode type was changed from Al to tungsten (W). .

[0074]

[Second Embodiment] As in the first embodiment, 2 × 2 × 0.5 mm
A diamond layer was formed on the Si substrate by microwave plasma CVD. In this example, only the insulating diamond layer was formed. Specific forming conditions are:
This is the same as the first embodiment. Generally, a diamond film formed by a microwave plasma CVD method has a surface conductive layer which is considered to be caused by hydrogen atoms bonded to the surface, and the surface conductive layer may function as a p-type. Are known. Therefore, the insulating diamond layer having the surface conductive layer is different from the p-type diamond layer as in the first embodiment in that the insulating diamond layer (electron supply layer) is used.
The structure can be considered to be the same as that of the case in which the layers are stacked. Therefore, as a result of evaluating the surface of the insulating diamond layer having the surface conductive layer, it was found that hydrogen was bonded to the outermost surface and the surface was in a negative electron affinity state.
Then, a part of the Si substrate was removed with a nitric acid-based etchant to form a hole, and an Al electrode was formed on the surface in contact with the substrate, and an Au / Ti electrode was formed on a part of the surface conductive layer. As a result, FIG.
A structure in which a diamond layer is sandwiched between two electrode layers as shown in FIG.

The electron-emitting device manufactured by the above method was placed in a vacuum of about 10 ⁻⁹ Torr, and a positive voltage was applied to the Al electrode side up to about 100 V. As a result, electrons were emitted from the surface conductive layer of diamond. The release was confirmed. The emission current ratio (emission efficiency) is about 0.1 to 10%,
It was confirmed that electrons were emitted more efficiently than before.

When the insulating diamond layer is formed under other forming conditions or when the substrate material is changed, the type of the electrode is changed to Al.
When W was changed to W, similar results were obtained.

[0077]

Third Embodiment As in the second embodiment, an insulative diamond layer having a surface conductive layer is formed on a Si substrate by microwave plasma CVD, and Al is formed on the surface in contact with the substrate. After forming the electrode, an insulating thickness of 0.1 μm is formed on a part of the surface of the insulating diamond layer (on the surface conductive layer).
A silicon dioxide layer (SiO ₂ ) was formed. The SiO ₂ film was formed by an rf sputtering method using a quartz disk as a target. Further, an Al electrode was formed on the SiO2 layer. As a result, a structure in which the electron supply layer, the diamond layer, and the insulator layer were interposed between the two electrode layers as shown in FIG. 2 was produced.

The electron-emitting device manufactured by the above method was placed in a vacuum of about 10 ^-9 Torr, and a positive voltage of about 100 V was applied to the Al electrode on the substrate surface. It was confirmed that more electrons were emitted, and that almost no current flowed through the Al electrode on the surface side.

Similar results were obtained when the insulating diamond layer was formed under other forming conditions, when the substrate material was changed, and when the type of electrode material was changed.

[0080]

Fourth Embodiment FIG. 7 shows an M-type semiconductor device using a diamond layer.
FIG. 3 is a diagram showing a basic structure of an embodiment of an electron-emitting device having an I-S-M structure . As shown in FIG. 7, the present electron-emitting device has, as main components, a first electrode layer 71, an insulator layer 72 such as i-type diamond as an electron supply layer, and a p-type diamond layer 73. , A base (conductive) 74 and an electrode layer 75 for applying an electric field to the element. By applying a positive voltage to the second electrode layer 75 of this device, the electrons injected from the electrode layer 71 are changed to an electron supply layer (insulator layer) 7.
2. Base material 74, electrode layer 75 via p-type diamond layer 73
, Resulting in a MISM structure diode current. The electron flow that flows near the surface of the p-type diamond layer 73 is emitted to the outside by diffusion or the like. Since this structure is a surface-emitting device, the surface current density can be increased.

FIG. 8A to FIG. 8F show the MI-
1 schematically shows a process used to fabricate an embodiment of an electron-emitting device having an SM structure .

First, as shown in FIG. 8A, a base material 74 was prepared. The substrate material is not particularly limited as long as it is electrically conductive, but a metal such as Si or molybdenum (Mo) is generally used in consideration of a post-process. In this example, a low-resistance Si substrate was used.

Next, as shown in FIG. 8B, an insulator film was formed as an electron supply layer 72 on the base material 74. The material of the electron supply layer (insulator layer) 72 is not particularly limited, but it is optimal to use an insulating i-type diamond to which impurities formed by vapor phase synthesis are not added.
Also in this embodiment, an i-type diamond layer was formed mainly by the microwave plasma CVD method as the electron supply layer (insulator layer) 72.

Subsequently, as shown in FIG. 8C, a part 76 of the back surface of the base material 74 was removed by etching. The etching method is not particularly limited, and is appropriately selected depending on the material of the base material 74 and the like. For example, when the base material 74 is Si, a wet etching method using hydrofluoric nitric acid can be used.

Further, as shown in an etching surface 77 of FIG. 8D, an electron supply layer (insulator layer: i-type diamond layer) 72
Was etched from the back side to reduce the thickness of the i-type diamond layer to less than 5 μm. The diamond layer was etched by ECR ion etching using oxygen gas or reactive ion etching (RIE). The conditions for ECR ion etching are as follows: gas pressure: 0.01 Torr, bias voltage: -30 V, bias current:
² mA / cm ² , microwave output: 650 W, substrate temperature: 280 ° C.

Thereafter, as shown in FIG. 8E, a p-type diamond layer 73 was formed on the etching surface 77 of the electron supply layer (insulator layer) 72. This p-type diamond layer may be formed by a new deposition by a gas phase synthesis method using a source gas to which a p-type impurity such as boron is added, or as described in the second embodiment, When i-type diamond is used as the insulator layer, a surface conductive layer whose surface is terminated with hydrogen by irradiating the etched surface with hydrogen plasma or the like may be formed as a p-type diamond layer.

Finally, as shown in FIG. 8F, the electrode layers 71 and 75
Was formed on an electron supply layer (insulator layer) 72 and a substrate 74, respectively. These electrode materials are generally appropriately selected from aluminum (Al), tungsten (W), gold / titanium (Au / Ti), and the like.

[0088] The above-described method by applying a voltage to the electron-emitting device manufactured by a current - results of evaluation of the voltage characteristic, rectification is obtained, it is operating as a M-I-S-M diode Was confirmed. Furthermore the present electron-emitting device 10 ^-9
The device was placed in a vacuum of about Torr, a forward bias was applied, and the electron emission characteristics were measured. As a result, the ratio of the emission current to the diode current flowing through the device (emission efficiency) was 0.1 to 1
It was about 0%, and it was confirmed that electrons were emitted more efficiently than in the past.

Further, in this embodiment, the electron supply layer (insulator layer: i-type diamond layer) 72 is thinned by etching from the back surface side. Even when a similar structure was formed by forming a surface conductive layer by hydrogenation, it was confirmed that electrons were emitted more efficiently than in the conventional case.

Also, when the nucleation density of the CVD diamond film is increased in advance to form a thin continuous film (thickness: 0.5 μm or less) and an electrode is formed without etching to produce an element. It was confirmed that electrons were emitted more efficiently than before.

Similar results were obtained when the diamond layer was formed under other forming conditions, when the substrate material was changed, and when the type of electrode material was changed.

First, a substrate was prepared. Although the substrate material is not particularly limited, Si is generally used in consideration of the post-process. In this embodiment, a high-resistance Si substrate was used.

Next, an n-type semiconductor layer was formed on the substrate as a part of the electron supply layer. The material of the n-type semiconductor layer is not particularly limited, but may be phosphorus (P) or nitrogen (N).
In general, n-type diamond or n-type silicon carbide doped with N is used. In particular, in the case of n-type diamond formed by a vapor phase synthesis method, an i-type or p-type diamond layer is formed in the same manner. Is most suitable because it can be easily formed. Therefore, in this embodiment, n-type diamond was used as the n-type semiconductor layer. The method of forming the n-type diamond layer is the same as described above, except that trimethyl phosphonate was added to the source gas as a P dopant. The addition amount of phosphorus is 1 × 10 ¹⁸ particles / cm ³ and the film thickness is 3 μm.
m. Then, an i-type diamond layer (thickness: about 1 μm) and a p-type diamond layer (thickness: 1 μm) as insulator layers included in the electron supply layer are successively formed thereon by microwave plasma CVD. Formed.

Subsequently, a part of the back surface of the substrate was removed by etching. The etching method is not particularly limited, and is appropriately selected depending on the material of the base material and the like. When the substrate is Si as in this embodiment, a wet etching method using hydrofluoric nitric acid can be used.

Finally, the surface of the electron supply layer on the substrate side and p
An ohmic electrode layer was formed on the surface of the mold diamond layer 94 on the front side. These electrode materials are generally Au
A / Ti two-layer electrode or the like is used.

The voltage was applied to the electron-emitting device manufactured by the above method, and the current-voltage characteristics were evaluated.
It was confirmed that the device operated as an n-junction diode. Further, the present electron-emitting device was placed in a vacuum of about 10 ^-9 Torr, a forward bias was applied, and the electron emission characteristics were measured. As a result, the ratio of the emission current to the diode current flowing through the element (emission efficiency) was 0.1. It was about 10%, which confirmed that electrons were emitted more efficiently than in the past.

Similar results were obtained when another material such as a silicon dioxide film was used as the i-layer.

[0098]

Fifth Embodiment (Reference Example 1) FIG. 9 shows the structure of a reference example of a pn junction type electron-emitting device using a diamond layer. As shown in FIG. 9, the present electron-emitting device has, as main components, a base material 91, an electrode layer 92,
An electron supply layer includes an n-type semiconductor layer 93 such as n-type diamond, a p-type diamond layer 94, and an electrode layer 95. By applying a forward bias between the electrode layers 92 and 95 of this element, the electron supply layer (n-type semiconductor layer)
From 93, electrons are injected into the p-type diamond layer 94, and pn
It becomes the junction diode current. A part of the electron flow that reaches the surface of the p-type diamond layer is emitted to the outside due to the negative electron affinity state. Also in this structure, since it is a surface emitting device, the surface current density can be increased.

FIG. 10A to FIG. 10F show the pn values shown in FIG.
FIG. 3 schematically shows a process used for manufacturing a reference example of a junction type electron-emitting device. First, the base material 91 was prepared. Although the substrate material is not particularly limited, Si is generally used in consideration of the post-process. In this embodiment, a high-resistance Si substrate was used.

Next, as shown in FIG. 10B, an n-type semiconductor layer was formed as an electron supply layer 93 on the base material 91. Although the material of the n-type semiconductor layer is not particularly limited, it is general to use n-type diamond or n-type silicon carbide doped with phosphorus (P) or nitrogen (N). The case of n-type diamond formed by a vapor phase synthesis method is optimal because a p-type diamond layer 94 can be easily formed by the same method. Therefore, in this embodiment, n-type diamond was used as the electron supply layer (n-type semiconductor layer) 93. The method of forming the n-type diamond layer is the same as described above, except that trimethyl phosphonate was added to the source gas as a P dopant. The addition amount of phosphorus was 1 × 10 ¹⁸ / cm ³ , and the film thickness was about 3 μm.

Further, as shown in FIG. 10C, a 1 μm-type p-type diamond layer 94 was formed thereon by microwave plasma CVD. The method for forming the p-type diamond layer is the same as described above.

Subsequently, as shown in FIG. 10D, a part 96 of the back surface of the base material 91 was removed by etching. The etching method is
It is not particularly limited, and is appropriately selected depending on the material of the base material 91 and the like. If the substrate 91 as in this reference example is Si can be used a method of wet etching with hydrofluoric-nitric acid.

Next, as shown in FIG. 10E, an ohmic electrode layer 92 was formed on a part of the etched portion 96 on the back surface of the base material 91 (the surface on the front side of the p-type diamond layer 94). As the electrode material, a two-layer Au / Ti electrode was used.

Finally, as shown in FIG. 10F, an ohmic electrode is formed on the surface of the electron supply layer (n-type semiconductor layer: n-type diamond layer) 93 on the substrate side and the surface of the p-type diamond layer 94 on the surface side. Layer 95 was formed. Similarly, as an electrode material,
An Au / Ti two-layer electrode was used.

As a result of applying a voltage to the electron-emitting device manufactured by the above-described method and evaluating current-voltage characteristics, it was confirmed that rectification was obtained and the device was operated as a pn junction diode. Furthermore, this electron-emitting device was placed in a vacuum of about 10 ^-9 Torr, a forward bias was applied to about 100 V, and the electron emission characteristics were measured. As a result, the ratio of the emission current to the diode current flowing through the element (emission efficiency) )is 0.
It was about 1 to 10%, and it was confirmed that electrons were emitted more efficiently than before.

In addition to the formation of an n-type diamond layer by the CVD method, P or N
Also function as an n-type diamond layer (electron supply layer) in the same manner as described above.

Similar results were obtained when the diamond layer was formed under other forming conditions, when the substrate material was changed, and when the type of electrode material was changed.

[0108]

Sixth Embodiment (Reference Example 2) As a method of controlling the surface structure of a diamond layer, a predetermined region of diamond was irradiated with vacuum ultraviolet light having a wavelength of 200 nm or less. First, a diamond layer having oxygen bonded to the surface was prepared. As a result of evaluating the electron affinity state of the diamond layer, it was found that the diamond layer was in a positive electron affinity state. Therefore, a part of the diamond layer having a positive electron affinity was irradiated with a vacuum ultraviolet light having a wavelength of 200 nm or less in a vacuum atmosphere of about 10 ⁻⁷ Torr or a hydrogen atmosphere. The irradiation amount of vacuum ultraviolet light at that time is not particularly limited because it depends on the irradiation rate and the like, but in this reference example, it is 10 ¹¹ per second.
The photons were irradiated for 15 minutes. As a result, the bond between oxygen and the outermost surface of the region irradiated with vacuum ultraviolet light is broken,
It was confirmed that the bond had changed to hydrogen. That is, it was found that the state of the electron affinity changed from positive to negative by changing the bonding state on the diamond layer surface. It has been confirmed that by using this process, it is possible to control the electron emission region serving as the emitter.

[0109]

Seventh Embodiment (Reference Example 3) As a method of controlling the surface structure of a diamond layer, a predetermined region of the diamond layer was exposed to plasma obtained by discharge-decomposing hydrogen gas. First, a diamond layer having oxygen bonded to the surface was prepared. This diamond layer is in a positive electron affinity state as described above. Then ECR of hydrogen gas
A part of the diamond layer having a positive electron affinity was exposed to the discharge plasma. The hydrogen plasma irradiation time at that time is 20 seconds. As a result, it was confirmed that the outermost carbon in the region exposed to the hydrogen plasma was changed to a bond with hydrogen. That is, it was found that the state of the electron affinity changed from positive to negative by changing the bonding state on the diamond layer surface. It has been confirmed that by using this process, it is possible to control the electron emission region serving as the emitter.

The same applies to the case where the time for exposing the hydrogen gas to the ECR discharge plasma is changed, the case where the hydrogen gas is diluted to about 10% with argon or nitrogen, and the case where the hydrogen gas is exposed to the hydrogen plasma formed by another method. Was obtained.

[0111]

Eighth Embodiment (Reference Example 4) As a method of controlling the surface structure of a diamond layer, a heated diamond layer was exposed to hydrogen gas. First, a diamond layer having oxygen bonded to the surface was prepared. This diamond layer is in a positive electron affinity state as described above. Therefore, a diamond layer having a positive electron affinity was set in a cylindrical container in which hydrogen gas was flown, and heated to 600 ° C.
The processing time at that time is 10 minutes. As a result, it was confirmed that the outermost surface carbon of the diamond layer heated in the hydrogen atmosphere was changed to a bond with hydrogen. That is, it was found that the state of the electron affinity changed from positive to negative by changing the bonding state on the diamond layer surface. It has been confirmed that by using this process, it is possible to control the electron emission region serving as the emitter.

Similar results were obtained when the hydrogen gas flowing into the container was diluted to about 10% with argon or nitrogen, or when the heating temperature was changed in the range of 400 to 900 ° C.

[0113]

Ninth Embodiment (Reference Example 5) As a method of controlling the surface structure of a diamond layer, a predetermined region of the diamond layer was exposed to plasma obtained by discharge-decomposing oxygen gas. First, a diamond layer having hydrogen bonded to the surface was prepared. As a result of evaluating the electron affinity state of the diamond layer, it was found that the diamond layer was in the negative electron affinity state as described above. Therefore, a part of the diamond layer having a negative electron affinity was exposed to oxygen gas ECR discharge plasma. The oxygen plasma irradiation time at that time is 20 seconds. As a result, it was confirmed that the outermost carbon in the region exposed to the oxygen plasma was changed to a bond with oxygen. That is, it was found that the state of the electron affinity changed from negative to positive by changing the bonding state on the surface of the diamond layer. It has been confirmed that by using this process, it is possible to control the electron emission region serving as the emitter.

The same applies when the time of exposing oxygen gas to ECR discharge plasma is changed, when oxygen gas is diluted to about 10% with argon or nitrogen, or when it is exposed to oxygen plasma formed by another method. Was obtained.

[0115]

Tenth Embodiment (Reference Example 6) As a method of controlling the surface structure of a diamond layer, a heated diamond layer was exposed to oxygen gas. First, a diamond layer having hydrogen bonded to the surface was prepared. This diamond layer is in a negative electron affinity state as described above. Therefore, a diamond layer having a negative electron affinity was set in a cylindrical container in which oxygen gas was flown, and heated to 600 ° C.
The processing time at that time is 10 minutes. As a result, it was confirmed that the outermost surface carbon of the diamond layer heated in the oxygen atmosphere was changed to a bond with oxygen. That is, it was found that the state of the electron affinity changed from negative to positive by changing the bonding state on the surface of the diamond layer. It has been confirmed that by using this process, it is possible to control the electron emission region serving as the emitter.

Similar results were obtained when the oxygen gas flowing through the container was diluted to about 10% with argon or nitrogen, or when the heating temperature was changed in the range of 400 to 650 ° C.

[0117]

As described above, according to the electron-emitting device of the present invention, there is provided an electron-emitting device formed using a diamond layer, comprising an electrode layer, an electron supply layer including at least an insulator layer, and a diamond layer. By applying an electric field to the electron supply layer, electrons can be efficiently supplied to the conduction band of diamond, and electrons can be easily extracted to the outside at low voltage and low temperature.

[Brief description of the drawings]

FIG. 1 is a view showing one embodiment of an electron-emitting device having a laminated structure including an electrode layer, an electron supply layer, and a diamond layer according to the present invention.

FIG. 2 is a view showing one embodiment of an electron-emitting device having a laminated structure including an electrode layer, an electron supply layer, a diamond layer, and an insulator layer according to the present invention.

FIG. 3 is a view showing one embodiment of a MIS type electron-emitting device using a diamond layer of the present invention.

FIGS. 4A and 4B are schematic diagrams showing energy bands of a MIS-type electron-emitting device using the diamond layer of the present invention.

FIG. 5 is a diagram showing a reference example of a pn junction type electron-emitting device using a diamond layer.

FIGS. 6A and 6B are schematic diagrams showing energy bands of a pn junction type electron-emitting device using a diamond layer of a reference example.

FIG. 7 is a cross-sectional view showing one embodiment of a MIS type electron-emitting device using the diamond layer of the present invention.

FIGS. 8A to 8F are views showing a process for forming an embodiment of the MIS type electron-emitting device using the diamond layer of the present invention.

FIG. 9 is a sectional view showing a reference example of a pn junction type electron-emitting device using a diamond layer.

10A to 10F are diagrams showing a process of a reference example of a pn junction type electron-emitting device using a diamond layer.

[Explanation of symbols]

11a, 11b, 11c, 21a, 21b, 21c, 35,52,55,75,92,95 Electrode layer 12,22 Electron supply layer 13,23 Diamond layer 14,24 Diamond layer surface 15,26 Emitted electrons 25 Insulation Body layer 31,51,91 Base material 32,71 Electrode layer (Schottky electrode) 33 Insulator layer (electron supply layer) 34,54,73,94 p-type diamond layer 53 n-type diamond layer 72 electron supply layer Insulator layer (i-type diamond layer) 74 Base material (conductive) 93 Electron supply layer n-type semiconductor layer (n-type diamond layer)

────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Akimitsu Hatta 2-2-1-17 Katayamacho, Suita-shi, Osaka (72) Inventor Nobuhiro Sakamori 4--18 Koyamacho, Kariya-shi, Aichi No.2 Koyama Dormitory (72) Inventor Makoto Kitabatake 1006 Kadoma Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (56) References JP-A-7-94081 (JP, A) JP-A-7-182994 (JP, A) JP-A-8 -222122 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) H01J 1/304 H01J 9/02

Claims (36)

(57) [Claims] A first electrode layer; a second electrode layer disposed opposite to the first electrode layer; and a second electrode layer disposed between the first electrode layer and the second electrode layer. An electron supply layer, comprising: a doped electron supply layer; and a diamond layer provided in contact with the electron supply layer, wherein the electron supply layer has an insulator layer, and a bias is applied to the electron supply layer. An electron-emitting device, wherein, when the electrons are emitted, electrons are supplied from the first electrode layer to the diamond layer via the insulator layer, and electrons are emitted from the diamond layer. 2. The electron-emitting device according to claim 1, wherein an electric field is applied to an electron supply layer sandwiched between the two electrodes by applying a voltage between the first electrode layer and the second electrode layer. . 3. The electron-emitting device according to claim 2, wherein the device operates at a voltage applied between the first electrode layer and the second electrode layer of 100 V or less. 4. The electron-emitting device according to claim 1, wherein the diamond layer has a thickness of 5 μm or less. 5. The diamond layer has at least an electric resistivity.
2. The electron-emitting device according to claim 1, comprising a conductive layer of 1 × 10 ⁴ Ω · cm or less. 6. The area of an electron emission surface of a diamond layer is 1
2. The electron-emitting device according to claim 1, which has a square μm or more. 7. The electron-emitting device according to claim 1, wherein the diamond layer includes at least a p-type diamond layer. 8. The electron-emitting device according to claim 7, wherein the boron (B) atom concentration in the p-type diamond layer is 1 × 10 ¹⁶ atoms / cm ³ or more. 9. The electron-emitting device according to claim 7, wherein the p-type diamond layer contained in the diamond layer has an electric resistivity of 1 × 10 ⁴ Ω · cm or less. 10. The method according to claim 1, wherein the electron emission surface of the diamond layer is C
The electron-emitting device according to claim 1, wherein the electron-emitting device is coated with at least one material selected from s, Ni, Ti, W, H, and amorphous-C. 11. The electron-emitting device according to claim 10, wherein the substance covering the electron-emitting surface of the diamond layer has an attached atom density of 1 × 10 ¹⁷ atoms / cm ² or less. 12. The first electrode layer and the second electrode layer are made of metal, the electron supply layer is an insulator layer, and the diamond layer contains a p-type diamond layer. -i
nsulator-semiconductor-metal) structure,
The electron-emitting device according to claim 1, wherein a positive voltage is applied to the second electrode layer having the SM structure to supply electrons to the p-type diamond layer. 13. The electron-emitting device according to claim 12, wherein the insulator layer of the electron supply layer is an i-type diamond layer. 14. The p-type diamond layer has a thickness of 5 μm.
The electron-emitting device according to claim 12, wherein: 15. The electron-emitting device according to claim 12, wherein the concentration of boron (B) atoms contained in the p-type diamond layer is 1 × 10 ¹⁶ atoms / cm ³ or more. 16. The electron-emitting device according to claim 12, wherein the p-type diamond layer has an electric resistivity of 1 × 10 ⁴ Ω · cm or less. 17. The electron-emitting device according to claim 13, wherein the electrical resistivity of the i-type diamond layer is 1 × 10 ⁴ Ω · cm or more. 18. The electric resistivity of the insulator layer is 1 × 10 ⁴ Ω ·
13. The electron-emitting device according to claim 12, which is not less than cm. 19. The semiconductor device according to claim 1, wherein the first electrode layer and the second electrode layer are made of metal, the electron supply layer includes an n-type semiconductor layer and an i-type semiconductor layer, and the diamond layer includes a p-type diamond layer. −N−I−P−M (metal-n layer-insulator-play
The er-metal) structure according to claim 1, wherein a positive voltage is applied to the second electrode layer of the MNIMP structure to supply electrons to the p-type diamond layer. Electron-emitting device. 20. The electron-emitting device according to claim 19, wherein the thickness of the p-type diamond layer is 5 μm or less. 21. The boron (B) atom concentration contained in the p-type diamond layer is 1 × 10 ¹⁶ atoms / cm ³ or more.
3. The electron-emitting device according to item 1. 22. The electron-emitting device according to claim 19, wherein the p-type diamond layer has an electric resistivity of 1 × 10 ⁴ Ω · cm or less. 23. An n-type semiconductor layer having an electric resistivity of 1 × 1
0 ⁴ Omega · electron-emitting device according to claim 19 cm or less. 24. The electric resistivity of the i-type semiconductor layer is 1 × 10 ⁴
20. The electron-emitting device according to claim 19, which has an ohm-cm or more. 25. An emitter part from which electrons are emitted is p
20. The surface of a diamond layer of a mold.
3. The electron-emitting device according to item 1. 26. The electron-emitting device according to claim 25, wherein a carbon atom on the outermost surface of the p-type diamond layer is terminated by a bond with a hydrogen atom. 27. The electron-emitting device according to claim 26, wherein the amount of hydrogen atoms bonded to carbon atoms on the outermost surface of the p-type diamond layer is 1 × 10 ¹⁵ atoms / cm ² or more. 28. The electron-emitting device according to claim 12, wherein a diamond surface conductive layer is used as the p-type diamond layer. 29. The electron-emitting device according to claim 28 , wherein the surface conductive layer of diamond has a structure in which carbon atoms on the outermost surface of the diamond layer are terminated by bonding to hydrogen atoms. 30. The electron-emitting device according to claim 29 , wherein the amount of hydrogen atoms bonded to carbon atoms on the outermost surface of the diamond layer is 1 × 10 ¹⁵ atoms / cm ² or more. 31. The electron-emitting device according to claim 12, wherein the structure of the electron-emitting device is a thin line having a width of 5 μm or less. 32. The electron-emitting device according to claim 12, wherein the diamond layer is formed by a vapor phase synthesis method. 33. A semiconductor device comprising : a first electrode layer; and a first electrode layer.
A second electrode layer disposed opposite to the first electrode layer;
An electron supply layer disposed between the second electrode layer and the second electrode layer;
A diamond layer provided in contact with the electron supply layer.
A method of manufacturing a continuous film-like diamond on a substrate material by a vapor phase synthesis method.
Forming a layer, a surface of the diamond layer on the substrate material side, and the diamond
At least one surface selected from the surface side of the monde layer
Etch the diamond layer from below to a predetermined thickness
A step of graying, after the etching step, to act a part as an electron supply layer
Of the substrate material side and the surface side of the diamond layer
And forming a first and second electrode layers in the region, producing side of the electron-emitting device, which comprises at least
Law. 34. Forming the first and second electrode layers
The method for manufacturing an electron-emitting device according to claim 33 , further comprising , before the step, irradiating a predetermined region of the diamond layer with vacuum ultraviolet light having a wavelength of 200 nm or less. 35. Forming the first and second electrode layers
Prior to the step, predetermined areas of the etched diamond layer are
Exposing hydrogen-containing gas to plasma obtained by discharge decomposition
The method for manufacturing an electron-emitting device according to claim 33 , comprising a step . 36. Forming the first and second electrode layers
The method for manufacturing an electron-emitting device according to claim 33 , further comprising , before the step, heating the diamond layer and exposing the diamond layer to a gas containing hydrogen.