JPH07254367A - Fine multi-electrode vacuum tube and manufacture thereof - Google Patents

Abstract

PURPOSE:To enhance efficiency, uniformity at the time of arraying, reliability of operation, and durability. CONSTITUTION:A first insulation layer 13 is disposed in a portion except for the tip of a projecting emitter 26 having a sharp end provided in on an emitter member layer 1. A gate electrode layer 21 where a portion surrounding the emitter 26 is formed into a cylindrical tapered shape along the circumferential surface of the emitter is superposed on the insulative layer 13. A second insulative layer 22 is mounted on the gate electrode layer 21. An anode electrode layer 23 where a portion surrounding the emitter 26 is formed into a cylindrical tapered shape along the circumferential surface of the emitter is mounted on the second insulative layer 22. At least the circumferential surfaces of the tips of the cylindrical portions in the gate electrode layer 21 and the anode electrode layer 23 are exposed at a solid angle viewed from the tip of the emitter 26.

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 micro-multipolar vacuum tube and a method for manufacturing the same.

[0002]

2. Description of the Related Art The operation speed of a semiconductor switching device is
Since it is determined by the mobility of carriers in the solid,
It is much slower than that of a triode tube that moves electrons in a vacuum. At present, various studies have been conducted to improve the operation speed of semiconductor switching elements, but they are already nearing the limit.

Under these circumstances, research on a micro multipole vacuum tube using a field emission type cold cathode (emitter) formed by utilizing a semiconductor processing technique has recently been actively conducted. A typical example is Spindt (CASpind
t) et al., Journal of Applied Physics, Vol.47, 5248 (19
Those described in 76) are known.

In the device described in the above-mentioned document, after forming a SiO ₂ insulating layer and a gate electrode layer on a Si single crystal substrate, a hole having a diameter of about 1.5 μm is made in both layers and A conical emitter for field emission is formed by vapor deposition. Specifically, Si on a Si single crystal substrate
An O ₂ insulating layer is formed by a deposition method such as a CVD method, and M is formed thereon.
A gate electrode layer made of an o layer or an Al layer is formed by a sputtering method. Then, after pinholes are formed in both layers by etching, a metal serving as an emitter, for example, Mo is vacuum-deposited from the vertical direction while rotating the substrate,
Utilizing the phenomenon that the diameter of the opening end of the pinhole gradually decreases as Mo is deposited on the gate electrode,
A conical emitter is deposited and formed on the substrate in the pinhole. Then, the anode electrode is arranged so as to face these emitters to complete the micro-multipolar vacuum tube.

However, in this method, since the conical emitter is formed in the pinhole by utilizing the rotary evaporation method, when a large number of emitters are simultaneously formed on the same substrate, the height of each emitter and Not only is the shape of the tip easily varied, but it is difficult to increase the sharpness of the emitter tip, which is essential for improving the field emission efficiency.

On the other hand, as another typical example, as described in Applied Physics, Vol. 59, p146 (1990), Si is used.
It is also known that a conical field emission type emitter is manufactured by using anisotropic etching on a single crystal substrate.

FIG. 5 shows the manufacturing process and structure. First, as shown in FIG. 3 (a), a SiN film 2 is deposited on the upper surface of a Si single crystal substrate 1 to a thickness of about 4 μm by sputtering, and on this SiN film 2, as shown in FIG. 1 (b). To
The photoresist 3 is provided in a circular shape. Next, a mask 4 for anisotropic etching is produced by the reactive ion etching method using SF ₆ . Next, as shown in FIG. 3C, the lower portion of the mask 4 is under-etched using an anisotropic etching solution to produce a conical emitter 5 with the mask 4 still attached.

Next, as shown in FIG. 3D, insulating layers 6 and 7 made of SiO ₂ and electrode layers 8 and 9 made of Ta or the like are alternately deposited twice. The electrode layer 8 is for a gate electrode, and the electrode layer 9 is for an anode electrode.

Finally, as shown in FIG. 1E, the portions of the insulating layers 6 and 7 and the electrode layers 8 and 9 located above the mask 4, the mask 4 and the mask 4 of the insulating layer 6.
After removing the portions located below, the final processing of the tip of the emitter 5 and the light etching of the insulating layer are performed with an anisotropic etching solution and hydrofluoric acid to complete the micromultipole vacuum tube. There is.

Since this method uses the anisotropic etching method for the Si single crystal, the sharpening of the tip of the emitter and the homogenization of the shape can be improved to some extent as compared with the above-mentioned rotary evaporation method. . However, it is difficult to control the under-etching time, and variations in peeling of the mask 4 are likely to occur, so that the sharpness of the emitter tip, the uniformity of the shape, and the reproducibility are not sufficient. Also,
Also in this method, there is a problem that the existence of the mask 4 becomes an obstacle, the gate cannot be brought sufficiently close to the emitter, and the distance between the emitter and the gate, which greatly affects the field emission efficiency, cannot be set accurately. The same applies to the anode, and the presence of the mask 4 becomes an obstacle, and it is necessary to provide a hole 10 larger than the diameter of the base portion of the emitter 5 in the portion facing the emitter 5. Therefore, in the anode, the portion receiving the electron flow emitted from the emitter 5 is limited to the edge portion located on the emitter side at the peripheral edge portion of the hole 10, and this portion is easily damaged by heat and is not only poor in durability. However, there is a problem that a part of the electron flow easily flows into the gate, resulting in poor efficiency. Further, the emitter material is required to have a small work function value and be physically and chemically stable. However, in this method, both properties are unsatisfactory.
However, there is also a problem that it cannot be used as an emitter material.

[0011]

As described above, in the conventional field emission type micro-multipole vacuum tube, it is difficult to increase the sharpness of the tip of the emitter, and it is difficult to improve the field emission efficiency. , It is difficult to make the shape of the emitter uniform, it is difficult to set the distance between the gate and emitter with high accuracy, the durability of the anode is poor, the efficiency is poor, There was a problem that the emitter material was specified. Therefore, the present invention is
It is an object of the present invention to provide a field emission type micro-multipolar vacuum tube capable of solving the above-mentioned problems and a method for manufacturing the same.

[0012]

In order to solve the above-mentioned problems, in a micro-multipolar vacuum tube according to claim 1, an emitter member having a projecting emitter portion having a sharp tip, and the emitter of the emitter member. A first insulating layer provided on a portion of the surface of the projecting portion other than the tip portion of the emitter section, and the first insulating layer provided on the first insulating layer,
And a second insulating layer provided on the gate electrode layer, wherein a portion surrounding the emitter section is formed in a tapered cylindrical shape along the peripheral surface section of the emitter section through the insulating layer of And a portion that is provided on the second insulating layer and that surrounds the emitter section with the second insulating layer, the gate electrode layer, and the first insulating layer interposed therebetween, is a peripheral surface section of the emitter section. At least one of the gate electrode layer and the anode electrode layer formed in the tube shape within a solid angle that can be seen from the tip of the emitter section. It is characterized in that the inner peripheral surface of the tip portion is located in an exposed state.

Here, when the diameter of the base portion of the emitter portion is D ₁ and the inner diameter of the distal end portion of the cylindrical portion of the anode electrode layer is D ₂ , a relationship satisfying D ₂ / D ₁ ≦ 0.8, In particular, it is preferable to satisfy D ₂ / D ₁ <0.5.

Further, the emitter member is formed of a surface material layer formed of a material having a small work function and being physically and chemically stable, and a material having a larger specific resistance than the constituent material of the surface material layer. It is preferably formed in a composite structure with the core material layer.

In the method for manufacturing a micro multi-electrode vacuum tube according to a fourth aspect of the present invention, a step of providing a recess having a sharpened lower portion on the auxiliary substrate,
Providing a first insulating layer on the surface of the auxiliary substrate including the inner surface of the recess, forming an emitter member layer on one exposed surface of the first insulating layer, and the auxiliary substrate To expose the other surface of the first insulating layer, a step of forming a gate electrode layer on the other surface of the first insulating layer, and the step of exposing the gate electrode layer. Forming a second insulating layer on the exposed surface, forming an anode electrode layer on the exposed surface of the second insulating layer, and forming on the emitter member layer due to the recess The raised portion as an emitter portion, and targeting the portions of the first insulating layer, the gate electrode layer, the second insulating layer, and the anode electrode layer that cover the emitter portion,
Each of the layers encloses the emitter section in a tapered cylindrical shape along the peripheral surface section of the emitter section, and within the solid angle that can be seen from the tip of the emitter section, the cylindrical sections of the gate electrode layer and the anode electrode layer are formed. And a step of removing a part of each of the layers so that at least the inner peripheral surface of the tip portion is located in an exposed state.

In the step of forming the emitter member layer, the work function is small on one exposed surface of the first insulating layer formed on the surface of the auxiliary substrate, and the physical / physical A step of forming a surface material layer made of a chemically stable material, and a core material layer made of a material having a larger specific resistance than the material forming the surface material layer on the exposed surface of the surface material layer. May be included.

[0017]

In the micromultipolar vacuum tube according to the first aspect, the portion of the gate electrode layer that surrounds the emitter section is formed into a tapered cylindrical shape along the peripheral surface section of the emitter section. By adjusting the thickness of the insulating layer, the gate can be brought sufficiently close to the emitter, and the distance between the gate and the emitter can be set accurately, so that the field emission efficiency can be improved. Also, with respect to the anode electrode layer, the portion surrounding the emitter portion is formed in a cylindrical shape that is tapered along the peripheral surface portion of the emitter portion. Therefore, by adjusting the thickness of the second insulating layer,
The gate-anode distance and the emitter-anode distance can be set accurately.

Further, in this case, by adopting the above-mentioned shape, the anode can be brought close to the extension line of the tip of the emitter, whereby the area of the portion for receiving the electron flow emitted from the emitter can be widened. Therefore, not only the thermal destruction of the anode can be prevented and the durability can be improved, but also the ratio of the electron flow emitted from the emitter toward the gate can be reduced, so that the efficiency can be improved.

The diameter of the base portion of the emitter is set to D ₁
And D ₂ is the inner diameter of the tip of the tubular portion of the anode electrode layer, D ₂ / D ₁ ≦ 0.8, preferably D ₂
By setting the relationship of / D ₁ <0.5, the area of the portion of the anode that receives the electron flow can be made sufficiently wide, and the above-described effect can be further exerted.

Further, the emitter member is composed of a surface material layer formed of a material having a small work function and being physically and chemically stable, and a core formed of a material having a specific resistance larger than that of the constituent material of the surface material layer. When formed into a composite structure with the material layer, each micromultipole vacuum tube can be stably operated when formed into an array. That is, the current flowing to the tip of the emitter section flows via the core material layer and the surface material layer. Since the core material layer is made of a material having a larger specific resistance than the surface material layer,
When a current is concentrated and flows in a specific emitter portion when arrayed, the voltage drop in the portion corresponding to the specific emitter portion in the core material layer automatically increases,
As a result, the current concentration on a specific emitter section is alleviated. Therefore, each micro multipole vacuum tube can be stably operated.

In the method for manufacturing a micro-multipolar vacuum tube according to a fourth aspect of the present invention, the emitter section can be provided with high precision, high sharpness, and evenness if the recessed portion provided in the auxiliary substrate is first provided with high precision. Can be made.

For example, if a Si single crystal substrate is used as the auxiliary substrate and anisotropic etching is performed by utilizing the crystal orientation of this substrate, a highly accurate recess such as an inverted pyramid can be formed. Then, a SiO ₂ thermal oxide film is formed on the surface including the inner surface of the recess of the auxiliary substrate, and this is used as the first insulating layer. The SiO ₂ thermal oxide film is dense and its thickness can be easily controlled, and the inward growth of the tip of the recess makes the tip of the inverted pyramidal space surrounded by the SiO ₂ thermal oxide film sharper. Let

According to the manufacturing method of the fourth aspect, finally, the emitter section is formed of the emitter member layer provided so as to fill the above-mentioned inverted pyramidal space having the sharpened tip. become. Therefore, with high accuracy,
In addition, it is possible to manufacture an emitter portion having a high sharpness and a uniform shape. Moreover, since the emitter portion can be made of a physically and chemically stable material having a small work function value, efficiency and durability can be improved.

In the step of forming the emitter member layer, the work function is small on one exposed surface of the first insulating layer formed on the surface of the auxiliary substrate, and physically and chemically. Form a surface material layer made of a stable material, and then form a core material layer made of a material having a larger specific resistance than the material forming the surface material layer on the exposed surface of the surface material layer. Then, as described above, it is possible to manufacture a device having a function of balancing the currents flowing to the respective emitters.

Materials having a small work function and stable physically and chemically include W, Mo, Ta and the like. When these materials are used to form the surface material layer by, for example, the sputtering method, the stress in the film formation is large.
It is not possible to make a thick film, but by adding a core material layer,
Substantially dense and thick emitter member layers can be formed. For the core material layer, ruthenium, carbon, silicon or the like can be used as a material having a large specific resistance.

[0026]

Embodiments will be described below with reference to the drawings. 1 (a) to 1 (h) show a manufacturing process of a micro multipole vacuum tube according to an embodiment of the present invention. The manufacturing method and structure of the micro multipole vacuum tube according to this embodiment will be described with reference to FIG. In this figure, one micro-multipolar vacuum tube is taken out and shown, but in reality, a plurality of micro-multipolar vacuum tubes are arranged in an array.

First, as shown in FIG. 1A, a Si single crystal substrate 11 as an auxiliary substrate is prepared, and a recess 12 having a sharp bottom is formed on one surface of the Si single crystal substrate 11.
As a method of forming such a recess 12, anisotropic etching on the Si single crystal substrate 11 is used. That is, first, a p-type Si single crystal substrate 1 having a (100) crystal plane orientation 1
An SiO ₂ thermal oxide film having a thickness of 0.1 μm is formed on the substrate 1 by a dry oxidation method, and a photoresist is applied on the thermal oxide film by a spin coating method. Next, using an optical stepper, the photoresist layer is subjected to patterning such as exposure and development so that a square opening of, for example, 0.8 μm square is obtained, and then the exposed SiO ₂ thermal oxide film is mixed with NH ₄ F / HF. Etch with solution. 30w after removing photoresist
Anisotropic etching is performed using a t% KOH aqueous solution to form an inverted pyramidal recess 12 having a depth of 0.56 μm in the Si single crystal substrate 11 as shown in FIG.

Next, using a mixed solution of NH ₄ F and HF,
The remaining SiO ₂ oxide film is removed. Next, Fig. 1 (b)
As shown in, a SiO ₂ thermal oxide film (hereinafter simply referred to as a first insulating layer) 13 is formed on the surface of the Si single crystal substrate 11 including the inner surface of the recess 12. In this example,
The first insulating layer 13 was formed by the dry oxidation method so as to have a thickness of 0.2 μm. When forming the first insulating layer 13, it can be formed by depositing SiO ₂ by a CVD method or the like. However, the SiO ₂ thermal oxide film is dense and the thickness can be easily controlled. It is preferable that the tip end portion of the inverted pyramid-like space surrounded by the SiO ₂ thermal oxide film is made sharper by the growth action to the.

Next, on the exposed one surface of the first insulating layer 13, the surface material layer 1 to be the surface layer of the emitter member layer 14.
5 is formed of, for example, a layer of W, Mo, Ta or the like. These materials have small work functions and are physically and chemically stable. In this embodiment, the surface material layer 15 has a thickness of 0.2.
A μm W layer was formed by a sputtering method. Next, on the surface material layer 15, a core material layer 16 serving as a core material of the emitter member layer 14 is provided with Lu having a larger specific resistance than the constituent material of the surface material layer 15,
The core material layer 16 is formed by sputtering to a thickness such that the surface becomes flat with C, Si or the like, and the conductive layer 17 such as ITO is formed on the core material layer 16 by sputtering, for example, with a thickness of 1 μm.
To be formed. The conductive layer 17 can be omitted depending on the material of the core material layer 16, and in that case, the core material layer 16 also serves as the cathode electrode layer.

On the other hand, as shown in FIG. 1 (c), a 1 mm thick Pyrex glass substrate 19 having a 0.4 μm thick Al layer 18 coated on its back surface is prepared as a structural substrate and is electrically connected to this glass substrate 19. The layer 17 is adhered. For this adhesion, for example, an electrostatic adhesion method can be applied. The electrostatic bonding method contributes to weight reduction and thickness reduction of the finally completed vacuum tube.

Next, as shown in FIG. 1D, the Al layer 18 on the back surface of the glass substrate 19 is covered with HNO ₃ .CH ₃ COOH.
After removing with a mixed acid solution of HF, an aqueous solution consisting of ethylenediamine / pyrocatechol / pyrazine (ethylenediamine: pyrocatechol: pyrazine: water = 75cc: 12g: 3mg
: 10 cc) to remove only the Si single crystal substrate 11 by etching to expose the other surface of the first insulating layer 13. By exposing the other surface of the first insulating layer 13, the surface becomes the first surface.
The pyramid-shaped convex portion 20 covered with the insulating layer 13 of FIG. The inside of the pyramid-shaped convex portion 20 is formed by the emitter member layer 14 described above.

Next, as shown in FIG. 1 (e), a W layer having a thickness of 0.2 μm to be the gate electrode layer 21 is sputtered on the first insulating layer 13 along the shape of the protrusion 20. Form by the method. Then, a 0.4 μm-thick SiO ₂ film to be the second insulating layer 22 is formed on the gate electrode layer 21 by an electron beam evaporation method, and then an anode electrode layer 23 is formed on the second insulating layer 22. A W layer having a thickness of 0.3 μm is formed by a sputtering method. Subsequently, a photoresist 24 is spin-coated on the anode electrode layer 23 to a thickness of about 0.
It is applied to a thickness of about 3 μm, that is, a thickness such that the tip of the pyramidal part is hidden.

Next, as shown in FIG. 1 (f), dry etching is carried out by oxygen plasma so that the photoresist 24 is exposed so that the tip of the pyramid-shaped portion is exposed to about 0.4 μm.
Are removed by etching.

Next, as shown in FIG. 1 (g), the portion of the anode electrode layer 23 forming the tip of the pyramid is removed by reactive ion etching, and an opening 25 is formed in this portion.

Next, after removing the photoresist 24,
A portion of the second insulating layer 22 located below the opening 25 and a portion located around the opening 25 are removed using a mixed solution of NH ₄ F and HF. Next, the photoresist is applied again. Then, the photoresist is removed by dry etching using oxygen plasma so that a portion of the gate electrode layer 21 located under the opening 25 is exposed by about 0.2 μm, and the photoresist is located under the opening 25 in the first insulating layer 13. Expose the part to be exposed.

Next, the photoresist is removed, followed by N
The exposed portion of the first insulating layer 13 was removed by using a mixed solution of H ₄ F and HF, and as shown in FIG.
A pyramidal emitter member layer 14 present therein,
That is, the tip of the emitter 26 is exposed.

Through these series of steps, the emitter member layer 14 having the protruding emitter portion 26 having a sharp tip is formed.
And a first insulating layer 13 provided on the surface of the emitter member layer 14 on the side where the emitter section 26 protrudes, excluding the tip of the emitter section 26, and the first insulating layer 1
And a gate electrode layer 21 in which a portion surrounding the emitter portion 26 via the first insulating layer 13 is formed in a tapered cylindrical shape along the peripheral surface portion of the emitter portion 26, and the gate electrode layer 21. Second insulating layer 22 provided on the layer 21
And a portion which is provided on the second insulating layer 22 and surrounds the emitter section 26 with the second insulating layer 22, the gate electrode layer 21 and the first insulating layer 13 interposed therebetween is a peripheral surface section of the emitter section 26. And a portion of the gate electrode layer 21 and the anode electrode layer 23 formed in the tubular shape within a solid angle that can be seen from the tip of the emitter section 26. This means that the minute multi-pole vacuum tube in which the inner peripheral surface of the tip portion is located in the exposed state is formed.

FIG. 2 is a perspective view in which the vicinity of the emitter section 26 is partially cut away at the time when the step shown in FIG. 1 (h) is completed. The micro-multipolar vacuum tube thus formed is used by being housed in a vacuum atmosphere.

As described above, in the micromultipole vacuum tube according to the above-mentioned embodiment, first, the recess 12 is formed in the Si single crystal substrate 11 as the auxiliary substrate by anisotropic etching, and then the Si single crystal substrate including the recess 12 is formed. A first insulating layer 13 made of a SiO ₂ thermal oxide film is formed on the surface of 11, and an emitter member layer 14 is formed on the surface of the first insulating layer 13. Therefore, the emitter portion 26 corresponding to the shape of the recess 12 is formed.
Can be formed with good reproducibility. In addition to the shape reproducibility due to the anisotropic etching described above,
Recess 12 by first insulating layer 13 made of O ₂ thermal oxide film
Of the pyramid-shaped emitter portion 26 with a sharp tip and excellent height uniformity due to the growth action of
Can be stably formed. Therefore, the field emission efficiency and the uniformity of the field emission efficiency of each emitter 26 can be improved.

Further, since the portion of the gate electrode layer 21 that surrounds the emitter portion 26 is formed in a tapered cylindrical shape along the peripheral surface portion of the emitter portion 26, the thickness of the first insulating layer 13 is reduced. By adjusting, the gate can be brought sufficiently close to the emitter and the distance between the gate and the emitter can be accurately set. Therefore, it is possible to improve the field emission efficiency.

Also, with respect to the anode electrode layer 23, the portion surrounding the emitter portion 26 is formed in a cylindrical shape which is tapered along the peripheral surface portion of the emitter portion 26, so that the second insulating layer 22 is formed. By adjusting the thickness, the gate-anode distance and the emitter-anode distance can be set accurately.

Further, since the above-described shape is adopted, the anode electrode layer 23 can be brought sufficiently close to the extension line of the tip of the emitter section 26, whereby the area of the portion for receiving the electron flow emitted from the emitter section 26. Can be widened. Therefore, not only the thermal destruction of the anode can be prevented and the durability can be improved, but also the ratio of the electron flow emitted from the emitter toward the gate can be reduced, so that the efficiency can be improved. As can be seen from the above description, the smaller the diameter of the opening 25 provided in the anode electrode layer 23, the better. As shown in FIG. 3, when the diameter of the base portion of the emitter portion 26 is D ₁ and the inner diameter of the opening portion 25 is D ₂ , D ₂ / D ₁ ≦
It is preferable to satisfy the relationship of 0.8, particularly D ₂ / D ₁ <0.5.

Further, since the emitter member layer 14 has a composite structure of the surface material layer 15 and the core material layer 16, it is possible to use a material satisfying the characteristics required for the emitter. That is, as in the embodiment, it is possible to use a physically and chemically stable material having a small work function as the surface material layer 15.
Further, when the core material layer 16 is formed of a material having a larger specific resistance than the constituent material of the surface material layer 15 as in the embodiment, the core material layer 16 can balance the currents flowing to the respective emitter portions 26. That is, when an electric current is attempted to flow in a specific emitter portion 26 when arrayed, the voltage drop in the portion of the core material layer 16 corresponding to the specific emitter portion automatically increases, and as a result, As a result, the concentration of current on a specific emitter section is alleviated. Therefore, it is possible to stably operate each of the arrayed minute multi-electrode vacuum tubes and prevent the occurrence of thermal breakdown caused by current concentration.

Although the emitter 26 is formed in a pyramid shape in the above-described embodiment, when it is desired to have a current capacity, the emitter 26a is formed in a roof shape as shown in FIG. Good to do. Such a shape can be realized by setting the shape of the opening of the mask to a rectangle when performing the anisotropic etching process on the Si single crystal auxiliary substrate. Further, a semiconductor layer containing boron is interposed between the first insulating layer 13 and the gate electrode layer 21,
The semiconductor layer may be used as an etching stop layer when the single crystal auxiliary substrate is removed by etching.

[0045]

As described above, according to the present invention,
The field emission efficiency is high, the uniformity when arrayed can be satisfied, and the reliability and durability of the operation when arrayed can be improved.

[Brief description of drawings]

FIG. 1 is a diagram for explaining a manufacturing process of a micro multipole vacuum tube according to an embodiment of the present invention.

FIG. 2 is a perspective view showing a partially cutaway micromultipolar vacuum tube manufactured through the manufacturing process.

FIG. 3 is an enlarged vertical cross-sectional view of a micro multipole vacuum tube manufactured through the manufacturing process.

FIG. 4 is a perspective view showing another shape of the emitter section.

FIG. 5 is a diagram for explaining an example of a conventional manufacturing process of a micro multipole vacuum tube.

[Explanation of symbols]

11 ... Auxiliary substrate 12 ... Recess 13 ... 1st insulating layer 14 ... Emitter member layer 15 ... Surface material layer 16 ... Core material layer 17 ... Conductive layer 20 ... Convex part 21 ... Gate electrode layer 22 ... Second insulating layer 23 ... Anode electrode layer 25 ... Openings 26, 26a ... Emitter section

Claims (5)

[Claims] 1. An emitter member having a tip-shaped sharp emitter portion, and an emitter member provided on a portion of the surface of the emitter member on which the emitter portion protrudes except the tip portion of the emitter portion. A first insulating layer and a portion provided on the first insulating layer and surrounding the emitter section with the first insulating layer interposed therebetween are formed in a tapered cylindrical shape along a peripheral surface section of the emitter section. And a second insulating layer provided on the gate electrode layer, and the second insulating layer, the gate electrode layer, and the second insulating layer provided on the second insulating layer. A portion surrounding the emitter portion via a first insulating layer, and an anode electrode layer formed in a tapered cylindrical shape along the peripheral surface portion of the emitter portion, and a solid angle which can be seen from the tip of the emitter portion. The gate electrode layer and the anode Micro multipolar vacuum tube, characterized in that at least the tip portion inner peripheral surface of the cylindrical shape portion formed of the cathode electrode layer is located in each exposure condition. Wherein the diameter of the base portion of the emitter section and D _1, when the tip inner diameter of the tubular portion in the anode electrode layer and a D _2, it meets D ₂ / D ₁ ≦ 0.8 The micromultipole vacuum tube according to claim 1, wherein 3. The work function of the emitter member is small,
In addition, it is characterized by being formed into a composite structure of a surface material layer formed of a physically and chemically stable material and a core material layer formed of a material having a larger specific resistance than the constituent material of the surface material layer. The micro multipole vacuum tube according to claim 1. 4. A step of providing a recess having a sharpened lower portion on the auxiliary substrate, and a first step on a surface of the auxiliary substrate including an inner surface of the recess.
Providing an insulating layer, forming an emitter member layer on one exposed surface of the first insulating layer, and removing the auxiliary substrate to the other surface of the first insulating layer. Exposing, a step of forming a gate electrode layer on the other surface of the first insulating layer, and a step of forming a second insulating layer on the exposed surface of the gate electrode layer. The step of forming an anode electrode layer on the exposed surface of the second insulating layer, and the convex portion formed in the emitter member layer due to the concave portion as an emitter portion, Layer, the gate electrode layer, the second insulating layer, and the anode electrode layer covering the emitter portion, the layers taper the emitter portion along the peripheral surface portion of the emitter portion. Enclosed in a cylinder and can be seen from the tip of the emitter section. And a step of removing a part of each of the layers so that at least the inner peripheral surfaces of the distal end portions of the cylindrical portions of the gate electrode layer and the anode electrode layer are exposed in a solid angle. And a method for manufacturing a triode vacuum tube. 5. The step of forming the emitter member layer has a small work function on one exposed surface of the first insulating layer formed on the surface of the auxiliary substrate, and a physical / physical A step of forming a surface material layer made of a chemically stable material, and a core material layer made of a material having a larger specific resistance than the material forming the surface material layer on the exposed surface of the surface material layer. 5. The method for manufacturing a micromultipole vacuum tube according to claim 4, further comprising: