JPH0765700A - Electron emission device and manufacture of electron emission device - Google Patents

Abstract

PURPOSE:To easily manufacture an electron emission device with high electron emission characteristics, high safety, and long performance maintaining capability by effectively utilizing the crystal structure of a diamond with (III) planes. CONSTITUTION:Diamond particles are deposited on the surfaces of seed crystals selectively arranged on a board 2 by the epitaxial growth of diamond in a vapor phase process. Or an emitter of diamond particles 3 is formed on the surfaces of seed crystals selectively arranged on the board 2 by the epitaxial growth of a diamond in a vapor phase process. An insulating layer 4 and a collector 5 are formed on the board 2 to manufacture an electron emission device 1. Since the diamond particle is idiomorphic by the growth of (III) planes, it has high electron emission characteristics.

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 and a method for manufacturing an electron-emitting device. An electron-emitting device that can be suitably used in a wide range of fields including electric and electronic fields such as a cathode, a flat CRT, an electron gun, and a high-frequency device, and an electron that can easily and simply manufacture such an electron-emitting device. The present invention relates to a method for manufacturing an emitting device.

[0002]

2. Description of the Related Art Conventionally, a display, an electron beam drawing apparatus,
Electron-emitting devices used in vacuum tubes, electron beam printers, etc.
It was formed of a material such as silicon, molybdenum, SiC, SiN ₄ . However, these materials do not have sufficient oxidation resistance, sputtering resistance, stability, etc., and the conventional electron-emitting device formed of these materials cannot emit electrons stably for a long period of time. Had.

By the way, diamond has a negative electronegativity, thermal conductivity, oxidation resistance, sputtering resistance,
It has the characteristics of excellent stability. In addition, (11
1) It has a unique crystal structure having a face. Recently, there have been proposed some electron-emitting devices in which the diamond is applied to an emitter to solve the conventional problems.

For example, US Pat. No. 4,943,7
No. 20 discloses an emitter in which a diamond thin film is coated on the tip of a steel rod-shaped substrate whose tip is cut into a conical shape to form a diamond tip.
However, in this case, since the angle of the tip of the diamond tip is large and not sharp, there is a problem that electrons cannot be efficiently and stably emitted. Further, Japanese Patent Laid-Open No. 4-67527 proposes a semiconductor electron emitting device using diamond for a p-type semiconductor layer.
However, this semiconductor electron-emitting device is a device that emits electrons by a specific amplification mechanism called avalanche amplification, and differs from a normal electron-emitting device in the principle of emitting electrons. In this device, the unique crystal structure of diamond having the (111) plane is not effectively utilized. Therefore, these electron-emitting devices still have problems, and an electron-emitting device without such a problem is desired.

The present invention effectively utilizes the crystal structure of diamond having a (111) plane to have high electron emission characteristics and stability, and its performance is not deteriorated for a long period of time. An electron-emitting device that can be suitably used in a wide field including electric / electronic fields such as flat CRTs, electron guns, and high-frequency devices, and an electron-emitting device that can easily and easily manufacture such an electron-emitting device. It aims at providing the manufacturing method of.

[0006]

The invention according to claim 1 for solving the above problems is a diamond obtained by epitaxially growing diamond by a vapor phase method on the surface of a seed crystal selectively provided on a substrate. An electron-emitting device having particles, wherein the invention according to claim 2 is characterized in that diamond particles are formed by epitaxially growing diamond on a surface of a seed crystal selectively provided on a substrate by a vapor phase method. Is formed, and then a collector is formed on the substrate.

Hereinafter, the electron-emitting device according to the present invention will be described in detail together with a method of manufacturing the electron-emitting device.

The electron-emitting device according to the present invention can be manufactured by the following method for manufacturing an electron-emitting device. In the method of manufacturing the electron-emitting device, 1) a step of selectively providing a seed crystal on a substrate (hereinafter referred to as a pretreatment step),
2) a step of forming diamond particles by epitaxially growing diamond on the surface of the seed crystal (hereinafter referred to as a diamond particle growing step);
3) A step of forming a collector on a substrate on which diamond particles are formed (hereinafter referred to as an element forming step).

1) Pretreatment Step In this pretreatment step, a seed crystal is selectively provided by forming a pattern on the substrate with a resist material containing a specific amount of the seed crystal.

[0010] - a substrate - The substrate is not particularly limited for its material, etc., for example Si, gallium - arsenic, SiC, SiO _2,
Si ₃ N ₄ , SrTiO ₃ , MgO, alumina, Al
Substrates that can be used as substrates for semiconductors such as N, ceramics, sapphire, and cemented carbide can be given. Of these, a Si substrate is preferable. In the present invention, a silicon wafer can be preferably used as the substrate. Further, the substrate may be a P-type or N-type semiconductor. The specific resistance of the substrate is usually 10 ⁻⁶ to 10 ³ Ω · cm.

-Formation of Pattern- To form the pattern, various known methods such as a lithography technique can be used. For example,
First, a resist material containing a specific amount of seed crystals is applied onto the substrate and dried. Next, the coating surface is exposed to light such as ultraviolet rays through a photomask having a light-shielding portion having a pattern of a desired shape or a pattern opposite thereto. Then, the unexposed portion is removed using a developing solution, a rinsing solution, a solvent, etc., whereby a pattern containing a seed crystal can be selectively formed on the substrate.

Examples of the seed crystal include fine particles of silicon, diamond and the like. In the present invention, these single crystal fine particles are preferable, and diamond single crystal fine particles are particularly preferable. The diamond fine particles may be natural or synthetic.

The particle size distribution of the seed crystal is usually 0 to 100 μm, preferably 0 to 10 μm, particularly preferably 0 to 0.5 μm or 0 to 0.2.
It is 5 μm. If the particle size distribution exceeds 100 μm,
It becomes difficult to uniformly disperse the seed crystal in the resist material,
It may not be possible to manufacture a device suitable as an emitter.

The content of the seed crystal in the resist material is usually 0.001 to 10% by weight, preferably 0.1 to 5% by weight. If the content is less than 0.001% by weight, an element suitable as an emitter may not be formed. On the other hand, if it exceeds 10% by weight, the dispersibility of the seed crystal in the resist material is deteriorated, and the resist material may not be uniformly applied onto the substrate.

Examples of the resist material include photoresists and resists for electron beams and X-rays.

The photoresist may be a negative photoresist or a positive photoresist. In addition to the commonly used resists, various known resin-based or rubber-based photoresists can be used. Examples of commercially available negative photoresists include LMR-3 manufactured by Fuji Yakuhin Kogyo Co., Ltd.
3 and OMR-83, OMR-8 manufactured by Tokyo Ohka Kogyo Co., Ltd.
5 etc. can be mentioned. In addition, as a commercially available product of the positive type photoresist, OF manufactured by Tokyo Ohka Kogyo Co., Ltd.
PR-2, OFPR-800, etc. can be mentioned.

The method for preparing the resist material is not particularly limited, and various known methods can be adopted. For example, first, the seed crystal is mixed with the resist material. Next, the resist material containing this seed crystal is irradiated with ultrasonic waves. Then, the seed crystals are uniformly mixed and dispersed in the resist material. Then, for example, this is 5 μm in diameter.
Filter with a Teflon filter or the like. Then, a uniform resist material from which secondary particles and large particles are removed can be prepared.

The application of the resist material can be carried out by a method such as spraying, spinner, dipping, brush coating, etc., and particularly preferably using a spinner.

The thickness of the resist material applied on the substrate is not particularly limited, but is usually 0.5 to 10
It is about μm.

Examples of the exposure method include a contact exposure method, a proximity exposure method, and a projection exposure method. These can be appropriately selected according to the purpose.

As described above, the pattern of the resist material containing the specific amount of the seed crystal is selectively formed on the substrate.

In this pretreatment step, it is preferable to remove the seed crystal remaining in the non-patterned portion on the substrate by performing the following cleaning operation. As the cleaning operation, a cleaning operation known per se can be adopted, and an ultrasonic cleaning operation can be preferably used.

The conditions of the ultrasonic cleaning are not particularly limited, and it is possible to use an ultrasonic cleaning device known per se, and to carry out the conditions appropriately selected. As a cleaning liquid used in the ultrasonic cleaning, for example, a resist rinsing liquid can be preferably cited.

Further, in this pretreatment step, it is preferable that the substrate is coated with a thin film of a carbon compound prior to the formation of the pattern.

The carbon compound is a compound which can be coated as a thin film on the substrate and has a property of burning at a temperature for forming diamond particles, specifically, a property of burning in plasma for forming diamond particles. If so, there is no particular limitation. Examples of such carbon compounds include compounds such as diamond-like carbon (DLC), glassy carbon, graphite and amorphous carbon, and compounds such as polyethylene, polystyrene, polypropylene and ABS resin, which include carbon and hydrogen, and polycarbonate and polyester. Carbon such as ethylene-vinyl acetate copolymer (EVA resin), ethylene-ethyl acrylate copolymer (EEA resin), polymethyl methacrylate resin, novolac resin, etc.
Mention may be made of compounds consisting of hydrogen and oxygen.
Further, in the present invention, a general resist agent for lithography can be used as the carbon compound. Among these, diamond-like carbon, glassy carbon, polyethylene, polystyrene, polycarbonate, and polyester are preferable, and particularly diamond-like carbon is preferable because generation of initial nuclei for forming diamond particles can be effectively suppressed. These may be used alone or in combination of two or more.

The method of coating the thin film on the substrate is not particularly limited and may be appropriately selected depending on the type of the carbon compound to be coated, but for example, CVD
Examples thereof include various known coating methods such as coating method, PVD method, plasma polymerization method, or coating method such as spin coater method and dip method.

The thickness of the thin film is usually 500 Å
It is 100 μm, preferably 1,000 Å to 10 μm, and particularly preferably 3,000 Å to 5 μm. When the thickness is within the above range, generation of initial nuclei for diamond formation in the non-diamond forming region can be effectively suppressed. As a result, diamond particles can be formed with high selectivity. On the other hand, if the thickness is less than 500 Å, the effect of forming the thin film of the carbon compound on the substrate is not sufficient, and the substrate due to the seed crystal remaining on the thin film of the carbon compound during the subsequent ultrasonic cleaning. Can be damaged. Also,
If it is thicker than 100 μm, the upper part of the pattern may be displaced during combustion in plasma.

2) Diamond grain growth step-In this diamond grain growth step, a diamond single crystal is epitaxially grown on the surface of the seed crystal according to various diamond vapor phase formation methods known per se using an apparatus known per se. .

The apparatus is not particularly limited, but an epitaxial growth apparatus can be preferably used in the present invention. Examples of the epitaxial growth apparatus include a molecular beam epitaxial growth apparatus, a gas source molecular beam epitaxial growth apparatus, an atomic layer epitaxial growth apparatus, a vapor phase epitaxial growth apparatus, a normal pressure vapor phase epitaxial growth apparatus, a reduced pressure epitaxial growth apparatus, a metal organic epitaxial growth apparatus, a photo vapor phase epitaxial growth apparatus, A liquid phase epitaxial growth apparatus, a solid phase epitaxial growth apparatus, etc. can be mentioned.

Examples of the diamond vapor phase forming method include CVD, PVD, PCVD, or a combination thereof. Among these,
Usually, various hot filament methods including the EACVD method, various direct current plasma CVD methods including the thermal plasma method, and microwave plasma CVD methods including the thermal plasma method are preferable.

Examples of the carbon source gas used in the diamond vapor phase formation method include paraffin hydrocarbons such as methane, ethane, propane and butane; olefin hydrocarbons such as ethylene, propylene and butylene; acetylene;
Acetylene-based hydrocarbons such as arylene; Diolefin-based hydrocarbons such as butadiene and allene; Alicyclic hydrocarbons such as cyclopropane, cyclobutane, cyclopentane and cyclohexane; Aromatic such as cyclobutadiene, benzene, toluene, xylene and naphthalene Hydrocarbons; Ketones such as acetone, diethyl ketone, benzophenone; Alcohols such as methanol, ethanol; Other oxygen-containing hydrocarbons; Amines such as trimethylamine and triethylamine; Other nitrogen-containing hydrocarbons; Carbon dioxide gas, one Carbon oxide,
Carbon peroxide etc. can be mentioned.

Among these, paraffin hydrocarbons such as methane, ethane and propane, alcohols such as ethanol and methanol, ketones such as acetone and benzophenone, amines such as trimethylamine and triethylamine, carbon dioxide and carbon monoxide. Is preferred, and carbon monoxide is particularly preferred.

Incidentally, these may be used alone,
Alternatively, two or more kinds may be used together as a mixed gas or the like.

Further, these may be used as a mixture with an active gas such as hydrogen or an inert gas such as helium, argon, neon, xenon or nitrogen.

The conditions for forming the diamond particles are not particularly limited, but for example, the reaction pressure is usually 10 ^−6.
10 to ³ Torr, preferably 1 to 760 Torr. When the reaction pressure is lower than 10 ⁻⁶ Torr, the formation rate of diamond particles may be slow. on the other hand,
Above 10 ³ Torr, as compared to the effect obtained when the 10 ³ Torr, it may not be more effective.

The surface temperature of the substrate cannot be unconditionally specified because it depends on the means for activating the carbon source gas and the like, but it is usually room temperature to 1200 ° C.
Room temperature-1100 degreeC is preferable. If the surface temperature of the substrate is lower than room temperature, diamond may not be able to grow sufficiently epitaxially. On the other hand, 1,2
When the temperature exceeds 00 ° C, the formed diamond particles may be easily etched.

The reaction time is not particularly limited, and it is preferable to set it appropriately according to the growth rate of diamond so that the diamond particles have a desired size.

The growth amount of the diamond particles is as follows.
Usually, the particle size is about 1.005 to 10 times, preferably 1.05 to 5 times. If it is less than 1.005 times, it may not grow sufficiently over the entire surface, and 1
Even if it grows beyond 0 times, the effect corresponding to it may not be obtained.

As described above, diamond can be epitaxially grown on the surface of the seed crystal selectively provided on the substrate, and diamond particles can be grown. The diamond particles thus obtained function as an emitter in an electron-emitting device. The diamond particles have a self-shape in which the (111) plane is grown,
It has high electron emission characteristics.

3) Element forming step In this element forming step, the collector is formed on the substrate on which the diamond particles as the emitter are formed, and further the gate (hereinafter sometimes referred to as the base) is formed if necessary. By doing so, an electron-emitting device is manufactured.

The electron-emitting device may be a tripolar device composed of an emitter, a gate and a collector, or a bipolar device composed of an emitter and a collector. The structure may be a point type or a wedge type, and these may be horizontal or vertical. Examples of the vertical type include a planar type, and a non-planar type such as a closed type, an open type, and an FET type.

As the collector, for example, silicon,
Examples thereof include Al, Au, Pt, Ti, Cr and Mo. The size and shape of the collector can be appropriately selected according to the size and shape of the emitter.

The collector can be formed, for example, as follows. That is, on the surface of the substrate, around the portion where the diamond thin film is formed,
A layer of an insulating material having a thickness thicker than the diamond thin film is formed. Then, it can be formed by disposing the collector on the surface of the layer made of the insulating material.

As the insulating material, for example, polyimide,
Examples thereof include silica and alumina. Among these, silica is preferable.

In the case of the triode element, the gate is further provided outside the emitter and collector. The material of the gate is Al, Au, Pt, Ti, C
r, Mo, etc. can be mentioned. The gate can be provided at a position between the collector and the diamond thin film, with a size and a shape selected appropriately.

The electron-emitting device can be manufactured by an appropriately selected method known per se.

Here, the production of the sandwich type electron-emitting device composed of the bipolar device will be specifically described. In this case, first, an insulating layer made of polyamide resin is formed around the portion where the diamond particles are formed on the substrate so that the insulating layer is thicker than the diamond particles. Then, a collector is arranged on the insulating layer made of the polyimide resin so as to cover and seal the diamond particles. Then, the diamond particles 3 formed on the surface of the substrate 2 as shown in FIG.
It is possible to manufacture the electron-emitting device 1 having the emitter, the insulating layer 4, and the collector 5.

The electron-emitting device manufactured as described above has diamond particles having a sharp tip as an emitter, and therefore has high electron-emitting characteristics and stability, and is suitable for electronic and electrical fields. It can be suitably used in a wide range of fields including the first.

[0049]

【Example】

(Example 1) 1) Pretreatment step-Substrate-A 30 × 10 mm p-type silicon wafer was used as a substrate.

-Pattern formation-First, a resist material containing diamond fine particles as seed crystals was prepared as follows. That is, a positive photoresist (manufactured by Tokyo Ohka Kogyo Co., Ltd., OFPR-80)
0, specific gravity; 1.02 g / cm ³ ) 3 ml was mixed with 0.05 g of synthetic diamond fine particles having a particle size distribution of 0 to 0.25 μm (manufactured by Tomei Diamond Industrial Co., Ltd .; fine grade type IMM). The mixture is irradiated with ultrasonic waves to uniformly disperse the diamond fine particles in the positive photoresist, and then the mixture is added with a diameter of 5
A diamond fine particle-containing resist material was prepared by filtering with a μm filter.

Next, this resist material was applied onto a substrate using a spin coater at a speed of 3 × 10 ³ rpm to a thickness of about 1 μm, and the applied surface was heated at 85 ° C. for 30 minutes.
Prebaked over a minute. After that, a photomask having a circular light-shielding portion with a diameter of 5 mm in the center is arranged on the coated surface, and the coated surface is exposed for 3 seconds using a resist aligner (PLA-501FA manufactured by Canon Sales Co., Ltd.). (13 mW / cm ² ). After the exposure, it was developed with a developer NMD-3 manufactured by Tokyo Ohka Kogyo Co., Ltd. for 60 seconds,
After rinsing with pure water, the exposed positive photoresist was removed and the substrate was heated at 135 ° C. for 30 minutes.

Next, the substrate on which the pattern of the resist material containing fine diamond particles was formed in this manner was subjected to ultrasonic cleaning, which was carried out by immersing the substrate in pure water for 5 minutes and repeating the pure water exchange three times. . The equipment used for ultrasonic cleaning is the Branson tabletop type manufactured by Yamato Scientific Co., Ltd.
The format is 2200.

2) Diamond grain growth step CO / H ₂ as a raw material gas was supplied at a rate of 10/90 scc by a microwave plasma CVD method (2.45 GHz).
at a flow rate of m, a reaction pressure of 40 Torr, a substrate temperature of 900 ° C., and a reaction time of 1 hour to form diamond particles as an emitter having a size of about 1 μm on the substrate. did.

3) Element Forming Step An insulating layer made of a polyimide resin having a thickness of 35 μm was formed around the portion where the diamond particles were formed on the substrate. Next, a p-type silicon substrate was used as a collector on the surface of the insulating layer, and the diamond particles functioning as the emitter were arranged so as to be sealed to form a sandwich type electron-emitting device composed of two poles. .

The IV characteristics of the obtained electron-emitting device were measured. Regarding the IV characteristics, a circuit was formed by connecting the substrate on which an emitter was formed to a cathode of a power source and connecting the collector to an anode of a power source, and installing an ammeter and a voltmeter in this circuit. After that, electricity was supplied, the current value and the voltage value were measured, and the measured values were assigned to the Fowler-Nordheim theoretical formula. The results are shown in the graph shown in FIG. 2 and as a white circle plot. In the graph shown in FIG. 2, A means current and V means voltage. As a result, good electron emission characteristics were observed, and
A current of 15 μA was obtained at 70V.

(Comparative Example 1) In order to observe whether or not the diamond fine particles as the seed crystal function as an emitter, the same as in Example 1 except that 2) the diamond particle growing step was not performed in Example 1. Then, an electron-emitting device was manufactured, and its IV characteristic was measured. The results are shown in the graph shown in FIG. 2 and as a black circle plot.
As a result, almost no electron emission was observed.

(Comparative Example 2) In Example 1, a diamond thin film synthesized without using a seed crystal was used.
An electron-emitting device was manufactured in the same manner as in 1. and its IV characteristic was measured. As a result, almost no electron emission was observed from the diamond thin film formed on the substrate.

[0058]

The electron-emitting device of the present invention is (111)
Since the crystal structure of diamond having a plane is effectively utilized, it has high electron emission characteristics and stability, and its performance does not deteriorate for a long time.
It can be suitably used in a wide range of fields including electric and electronic fields such as T, electron guns, and high frequency devices. Further, the electron-emitting device manufacturing method of the present invention can easily and simply manufacture such an electron-emitting device.

[Brief description of drawings]

FIG. 1 is a schematic cross sectional view showing an embodiment of an electron-emitting device according to the present invention.

FIG. 2 is an explanatory diagram showing an example of electron emission characteristics in the electron emitting device of the present invention.

[Explanation of sign]

1 ... Electron emitting device, 2 ... Substrate, 3 ... Diamond particles, 4 ... Insulating layer, 5 ... Collector,

Claims (2)

[Claims] 1. An electron-emitting device characterized in that it has diamond particles formed by epitaxially growing diamond by a vapor phase method on the surface of a seed crystal selectively provided on a substrate. 2. An emitter of diamond particles is formed by epitaxially growing diamond by a vapor phase method on the surface of a seed crystal selectively provided on a substrate, and then a collector is formed on the substrate. Method of manufacturing electron-emitting device.