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WO2010123007A1 - Source d'électrons à émission de champ à cathode froide comprenant un hexaborure de terre rare - Google Patents

Source d'électrons à émission de champ à cathode froide comprenant un hexaborure de terre rare Download PDF

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WO2010123007A1
WO2010123007A1 PCT/JP2010/057018 JP2010057018W WO2010123007A1 WO 2010123007 A1 WO2010123007 A1 WO 2010123007A1 JP 2010057018 W JP2010057018 W JP 2010057018W WO 2010123007 A1 WO2010123007 A1 WO 2010123007A1
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Prior art keywords
electron source
single crystal
cold cathode
field emission
cathode field
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Japanese (ja)
Inventor
捷 唐
▲はん▼ 張
禄昌 秦
紀雄 新谷
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National Institute for Materials Science
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J1/00—Details of electrodes, of magnetic control means, of screens, or of the mounting or spacing thereof, common to two or more basic types of discharge tubes or lamps
    • H01J1/02—Main electrodes
    • H01J1/30—Cold cathodes, e.g. field-emissive cathode
    • H01J1/304—Field-emissive cathodes
    • H01J1/3042—Field-emissive cathodes microengineered, e.g. Spindt-type
    • H01J1/3044—Point emitters
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J37/00—Discharge tubes with provision for introducing objects or material to be exposed to the discharge, e.g. for the purpose of examination or processing thereof
    • H01J37/02—Details
    • H01J37/04—Arrangements of electrodes and associated parts for generating or controlling the discharge, e.g. electron-optical arrangement or ion-optical arrangement
    • H01J37/06—Electron sources; Electron guns
    • H01J37/065—Construction of guns or parts thereof
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J37/00—Discharge tubes with provision for introducing objects or material to be exposed to the discharge, e.g. for the purpose of examination or processing thereof
    • H01J37/02—Details
    • H01J37/04—Arrangements of electrodes and associated parts for generating or controlling the discharge, e.g. electron-optical arrangement or ion-optical arrangement
    • H01J37/06—Electron sources; Electron guns
    • H01J37/073—Electron guns using field emission, photo emission, or secondary emission electron sources
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J2201/00—Electrodes common to discharge tubes
    • H01J2201/30—Cold cathodes
    • H01J2201/304—Field emission cathodes
    • H01J2201/30446—Field emission cathodes characterised by the emitter material
    • H01J2201/30492—Borides
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J2237/00—Discharge tubes exposing object to beam, e.g. for analysis treatment, etching, imaging
    • H01J2237/06—Sources
    • H01J2237/063—Electron sources
    • H01J2237/06325—Cold-cathode sources
    • H01J2237/06341—Field emission
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J2237/00—Discharge tubes exposing object to beam, e.g. for analysis treatment, etching, imaging
    • H01J2237/26—Electron or ion microscopes

Definitions

  • the present invention relates to a cold cathode field emission electron source that emits electrons by a high electric field using a rare earth hexaboride nanofiber.
  • tungsten, rare earth hexaboride, or the like is used as an electron source material for a hot cathode electron source, and tungsten is used for a cold cathode field emission electron source.
  • Table 1 shows a hot cathode electron source using tungsten, a hot cathode electron source using lanthanum hexaboride as a rare earth hexaboride (Non-patent Document 1), and a cold cathode field emission type using a high electric field load using tungsten. The characteristics of the electron source are compared and shown.
  • lanthanum hexaboride Comparing the hot cathode electron source 1 using tungsten (W) and the hot cathode electron source 2 using lanthanum hexaboride (LaB 6 ), lanthanum hexaboride has higher brightness and less energy spread than tungsten. It can be seen that it has a long life. Further, the cold cathode field emission electron source 3 using tungsten is an electron beam which is much smaller in luminance, less in energy spread, narrowly focused, and has a longer life than the two types of hot cathode electron sources. It turns out that it is a long and excellent electron source.
  • lanthanum hexaboride as a rare earth hexaboride shows the physical properties related to the electron source characteristic of cerium hexaboride (CeB 6) and hexaboride gadolinium (GdB 6) compared to tungsten. From this comparison, rare earth hexaboride has a low work function compared to tungsten and is easy to emit electrons by an electric field, and also has excellent hardness and durability, high melting point and low electrical resistance, etc. It can be seen that it has characteristics.
  • the electron source can be improved in brightness, life of the electron source, and energy spread can be suppressed.
  • the inventors have been searching for a new material that is superior to tungsten as the electron source material of the cold cathode field emission electron source.
  • the material used as a cold cathode field emission electron source requires a high electric field at the tip of the electron source, and therefore the electron used because the tip of the electron source must be a single crystal nanofiber sharpened to the nano level. Source materials are limited.
  • the cold cathode field emission has durability that does not cause chemical reaction or damage between the electron source material and the electron source support needle even when exposed to high temperature by flashing treatment while maintaining the high performance of the cold cathode field emission electron source.
  • Development of a type electron source was expected. JP 2008-262794 A JP 2003-7196 A JP-A-56-61734 J. Appl. Phys. 68 (7), 1 October 1990, 3614-3618, H. Nagata, K. Harada, R. Shimizu (first page, Fig. 7) Journal of Crystal Growth 44 (1978) 106-109, S. Motojima, Y. Takahashi, K. Sugiyama (1st page, Fig.
  • An object of the present invention is to provide an electron source that realizes the application of rare earth hexaboride to a cold cathode field emission electron source, prevents damage and deterioration due to a chemical reaction, has excellent durability, and can be used for a long period of time. It is said.
  • the present inventors have used single-crystal nanofibers of rare earth hexaboride as an electron source material, and further used an electron source support needle with a specific material and structure. As a result, it was found that a cold cathode field emission electron source with excellent performance could be obtained, and the present invention was completed based on this finding.
  • the electron source of the present invention is characterized by the following.
  • a cold cathode field emission electron source that emits electrons by a high electric field, wherein a rare earth hexaboride single crystal nanofiber is attached to the surface of an electron source support needle.
  • the rare earth hexaboride single crystal nanofiber is a single crystal nanofiber of at least one of lanthanum hexaboride, cerium hexaboride, and gadolinium hexaboride.
  • the single crystal nanofiber is a single crystal nanofiber having a diameter of 10 to 300 nm manufactured by a vapor phase growth method.
  • the end face of the single crystal nanofiber is the (001) crystal face.
  • the electron source support needle has a connection portion between the electron source support needle and the rare earth hexaboride single crystal nanofiber even when the cold cathode field emission electron source is at a high temperature. Made of materials that do not react chemically.
  • a terrace-shaped flat portion is provided at the tip of the electron source support needle in parallel with the axial direction of the electron source support needle, and the rare earth hexaboride single crystal nanofibers are arranged in parallel with the axial direction. It is bonded by vapor deposition.
  • the electron source support needle is made of rhenium, osnium, platinum or iridium.
  • the surface of the electron source support needle bonded to the rare earth hexaboride single crystal nanofiber is made of a material that does not chemically react with the rare earth hexaboride single crystal nanofiber even at a high temperature.
  • a tip-like flat portion is provided at the tip of the electron source support needle in parallel with the axial direction of the electron source support needle, and the rare earth hexaboride single crystal nanofiber is disposed in parallel with the axial direction, Conductive material is deposited and bonded.
  • the surface to be bonded to the rare earth hexaboride single crystal nanofiber of the electron source support needle is coated with rhenium, osnium, platinum or iridium.
  • the electron source support needle is made of tantalum, titanium, zirconium, hafnium, or nickel, and the surface to be bonded to the rare earth hexaboride single crystal nanofiber is coated with carbide or boride.
  • a rare-earth hexaboride with a low work function was used as a single crystal nanofiber with easy electron emission, used as an electron source, and the type of rare-earth hexaboride was specified.
  • cold-cathode field emission electron sources that use this have an excellent current-voltage characteristic of the electron source, are extremely stable with almost no fluctuations in current due to electron emission, and are used for a long time. Thus, an excellent cold cathode field emission electron source can be obtained.
  • the single crystal nanofiber is manufactured by the vapor phase growth method, the diameter is specified, and the crystal face of the end face is specified, the material can be further suitable for the cold cathode field emission electron source.
  • the position of the rare earth hexaboride single crystal nanofiber is controlled and arranged, and then it is configured to deposit in a patch from a specific material on the single crystal nanofiber.
  • the position fixing of the single crystal nanofiber can be ensured, and the mechanically and electrically continuous continuous bonding can be achieved.
  • the electron source support needle is made of a heat-resistant metal that is stable at a high temperature such as rhenium and does not react with the rare earth hexaboride as the material of the electron source support needle.
  • the electron source support needle and the single crystal nanofiber By coating only the joint surface with a heat-resistant metal such as rhenium that does not react at high temperatures, and further coating only the joint surface with carbide or boride, damage and deterioration of the single crystal nanofiber can be prevented. .
  • the present invention it is possible to solve the problems of bonding rare earth hexaboride single crystal nanofibers to an electron source support needle and damage / deterioration problems associated with use at high temperatures as an electron emission source. As a source, it can be used stably for a long time.
  • the graph showing the current-voltage characteristic of the lanthanum hexaboride single crystal nanofiber electron source by a field emission characteristic apparatus The graph showing the comparison of the current-voltage characteristic of a rare earth hexaboride cold cathode field emission electron source and an existing tungsten and zirconium oxide coated tungsten Schottky electron source.
  • Schematic which shows the basic structure of the electron source which uses a rare earth hexaboride single crystal nanofiber as an electron emission source.
  • FIG. 1 Schematic showing the shape which produces the electron source support needle
  • FIG. 1 is a side view
  • FIG. 1 is a front view
  • FIG. 1 is a side view
  • FIG. 1 is a front view
  • FIG. 1 is a side view
  • FIG. 1 is a front view
  • FIG. 1 is a top view.
  • (A) is a photograph from the top surface
  • (b) is a photograph from the side surface. Schematic showing the production shape by electrolytic processing of the tungsten support needle which uses platinum, osmium, iridium, carbon, or rhenium as a barrier layer.
  • (A) is a side view
  • (b) is a front view
  • (c) is a top view.
  • (A) is a side view
  • (b) is a front view
  • (c) is a top view.
  • FIG. 1 Schematic representing the coating of a barrier layer such as platinum on a tungsten support needle to prevent reaction between the tungsten support needle and the rare earth hexaboride nanofiber.
  • A is a side view
  • (b) is a front view
  • (c) is a top view.
  • FIG.) is a side view
  • (b) is a front view
  • (c) is a top view.
  • the schematic diagram showing the process by the focused ion beam apparatus of the electron source support needle tip parts, such as tantalum, produced by electrolytic processing, and the process of a terrace-like flat part.
  • (A) is a side view
  • (b) is a front view
  • (c) is a top view.
  • (A) is a side view
  • (b) is a front view
  • (c) is a top view.
  • (A) is a side view
  • (b) is a front view
  • (c) is a top view.
  • the left figure is a photograph before heating, and the right figure is a photograph after heating.
  • hook with a carbon vapor deposition barrier layer and lanthanum hexaboride nanofiber which are shown in FIG.
  • the left figure is a photograph before heating, and the right figure is a photograph after heating.
  • the rare earth hexaboride has excellent physical properties necessary for use as an electron source material as shown in Table 2 above.
  • a cold cathode field emission method that emits electrons only by an electric field instead of thermionic emission by heating, the luminance is improved by orders of magnitude and the spread of energy is suppressed as shown in Table 1 above. be able to.
  • a single crystal nanofiber of rare earth hexaboride is used as an electron source material, so that electrons are emitted without heating and under the voltage load conditions conventionally used for hot cathode electron sources. It was revealed for the first time that it would be a cold cathode field emission electron source.
  • the rare earth hexaboride used as the electron source material of the cold cathode field emission electron source of the present invention at least one of lanthanum hexaboride, cerium hexaboride and gadolinium hexaboride can be used, and it has been conventionally used.
  • Electron source material for the hot cathode electron source and the electron source material for the cold cathode field emission electron source. Can be a source.
  • Table 3 shows the characteristics predicted from the measurement data of the cold cathode field emission electron source using the lanthanum hexaboride single crystal nanofiber implemented in the present invention.
  • the cold cathode field emission electron source using rare earth hexaboride as an electron source material is much more effective than the conventional hot cathode electron sources shown in Table 1 and cold cathode field emission electron sources using tungsten. It can be seen that the performance is improved.
  • the cold cathode field emission electron source using the rare earth hexaboride of the present invention as an electron source material is a transmission type instead of a conventional hot cathode electron source or a cold cathode field emission electron source using tungsten as an electron source material. It can be incorporated in an electron gun of an electron microscope, a scanning electron microscope, or an electron beam drawing apparatus, and the performance of these apparatuses can be remarkably improved. Taking a transmission electron microscope as an example, it is predicted how much the resolution will be improved, and Table 4 shows a comparison with a conventional electron source.
  • the resolution of the transmission electron microscope can be 1 mm or less.
  • the degree to which the resolution can be improved will depend on future research, but there is no doubt that it will be much better than the current field-emission electron source using tungsten.
  • the ability to reduce the resolution to 1 mm or less is significant because most atoms can be clearly observed.
  • the single-crystal nanofibers used in the following examples can be produced using chemical vapor deposition (CVD) disclosed in Patent Document 1.
  • CVD chemical vapor deposition
  • single crystal nanofibers of lanthanum hexaboride are reacted in a tubular furnace based on the following reaction formula (1) shown in Non-Patent Document 3, and are formed on a silicon substrate in the furnace.
  • Lanthanum hexaboride single crystal nanofibers can be produced.
  • cerium hexaboride and gadolinium hexaboride can also be produced based on the reaction formulas shown in the following chemical formulas (2) and (3).
  • the effectiveness of the rare earth hexaboride single crystal nanofiber produced by the above method as an electron source material for a cold cathode field emission electron source can be estimated by the following method.
  • the tip of the electron source material of the cold cathode field emission electron source needs to have a high potential and concentrate the electric field in order to emit electrons by the quantum mechanical tunnel effect.
  • the potential at the tip of the electron source is expressed by the following equation (Non-patent Document 6).
  • E 1.2V (2.5 + h / r) 0.9 [1 + 0.013d / (dh) -0.033 (1-h / d)] / d (1)
  • V load voltage
  • r radius of the tip of the electron source
  • h length of the electron source
  • d distance between the anode and the tip of the electron source
  • the rare earth hexaboride single crystal nanofiber in the present invention is compared with the potential at the tip of the cone type bulk electron source material used as the hot cathode electron source.
  • the radius of the single crystal nanofiber was 10 nm, and the length of the electron source material beyond the support needle was 5 ⁇ m.
  • the conventional cone type bulk electron source has a radius of 2.5 ⁇ m and a length of 5 ⁇ m, and the distance (d) between the anode and the electron source tip is the same.
  • the tip of the single crystal nanofiber electron source has a potential about 250 times that of the bulk electron source. Therefore, it can be confirmed that the single crystal nanofiber of the present invention can be used as a cold cathode electron source material even for a power supply system used in a conventional electron source.
  • the dimensions of the rare-earth hexaboride single-crystal nanofiber used as the cold cathode field emission electron source material of the present invention are 10 to 300 nm in diameter, and the dimensions of the tip portion ahead of the support needle are as follows. A length of 1 to 10 ⁇ m is preferred.
  • the cold cathode field emission electron source using a conventional tungsten fiber has a diameter of 3 nm (Table 1). However, since rare earth hexaboride has a work function much lower than that of tungsten, the electric field is within the range of 10 to 300 nm. Electron emission due to occurs easily. The smaller the diameter of the nanofiber, the larger the electric field concentration and the easier the electron emission.
  • the diameter limit of 300 nm is determined from the electric field concentration (formula (1)) and the work function. The longer the electron source, the greater the electric field concentration (formula (1)). Moreover, when shorter than 1 micrometer, there exists a possibility that stability of an electron source may become unstable.
  • a field emission characteristic measuring device was prototyped and a large amount of electrons were emitted at a voltage load of 3 kV.
  • the current-voltage characteristics of the electron source were orders of magnitude higher than those of conventional electron sources.
  • the rare earth hexaboride single crystal nano-crystals were clarified for the first time such as superiority, almost no fluctuation of current due to electron emission, extremely stable, little influence by long-time use, and excellent durability. It was confirmed that the fiber can be used for a cold cathode field emission electron source, and further, is an extremely excellent electron source.
  • the crystal structure and characteristics of the electron source are also examined.
  • the single crystal nanofiber with the crystal orientation (001) has no crystal disorder and little damage.
  • the (001) crystal plane, in which the end face of the nanofiber emitting electrons is perpendicular to the crystal orientation, is particularly easy to emit electrons, stable, and can be an excellent cold cathode field emission electron source nanofiber. I found it.
  • FIG. 9 shows the basic structure of an electron source using a rare earth hexaboride single crystal nanofiber as an electron source material.
  • This has a structure in which a rare earth hexaboride single crystal nanofiber is bonded to the tip of an electron source support needle, and the electron source support needle is bonded to a conventional filament.
  • a flushing process of heating to about 1000 ° C. is performed in order to remove contamination on the surface of the electron emission source.
  • the material of the electron source support needle of the present invention does not cause a reaction at the interface with the single crystal nanofiber in order to prevent damage and deterioration associated with the flushing treatment of the rare earth hexaboride single crystal nanofiber at a high temperature.
  • a material that does not diffuse and penetrate into the nanofiber and does not produce a deteriorated phase is selected and used.
  • Such materials include rhenium, osnium, platinum, and iridium. These materials can be used not only as the material itself but also as a coating only on the surface of the junction with the rare earth hexaboride single crystal nanofiber.
  • the material of the electron source support can be tantalum, titanium, zirconium, hafnium, nickel.
  • the surface of the joint portion with the rare earth hexaboride single crystal nanofiber is coated with carbide or boride. Can be used.
  • the electron source support needle of the present invention can be attached with a single crystal nanofiber by providing a flat terrace-like flat part parallel to the axial direction of the needle at the tip part.
  • the terrace-shaped formation method is not particularly limited, but formation by a focused ion beam is preferable from the viewpoint of formability.
  • rare earth hexaboride single crystal nanofibers By arranging rare earth hexaboride single crystal nanofibers on the terrace-like flat part with the central axis aligned, and depositing carbon or platinum from the center axis, continuous mechanically and electrically bonding can be achieved. can do.
  • FIG. 10 is a side view of the electron source support needle
  • FIG. 10B is a front view
  • FIG. 10C is a top view.
  • the tip portion of the electron source support needle is cut off, and a terrace-like flat portion is processed inside thereof, Make it.
  • the flat portion has a width of 1 to 20 ⁇ m and a length of 1 to 100 ⁇ m, and is processed by a focused ion beam apparatus.
  • Tungsten is often used as an electron emission source.
  • it is used as an electron source support needle for supporting a rare earth hexaboride single crystal nanofiber.
  • the shape of FIG. 13 is processed by electrolytic processing of tungsten wire.
  • (A), (b), and (c) in the figure are a side view, a front view, and a top view after electrolytic processing.
  • the tip of the tungsten needle having the shape shown in FIG.
  • the width of the terrace-shaped flat portion whose shape is shown in FIG. 14 is 1 to 20 ⁇ m and the length is 1 to 100 ⁇ m.
  • platinum, osnium, iridium, carbon or rhenium is vapor-deposited, and the coating layer is formed. Make it.
  • a rare earth hexaboride single crystal nanofiber is disposed on the coating layer, and carbon or platinum is deposited in a patch shape to produce the tip of the electron emission source.
  • ⁇ Preparation example of electron source support needle using carbide or boride as barrier layer> An example of manufacturing a barrier layer by using cheaper and common tantalum, titanium, zirconium or nickel as an electron source support needle, and forming these carbides or borides with a rare-earth hexaboride single crystal nanofiber. It is. Tantalum, titanium, zirconium or nickel is processed into the shape shown in FIG. 16 by electrolytic processing. The electron source support needle of this shape is processed as shown in FIG. 17 by a focused ion beam device, the tip portion is cut off, and a terrace-like flat portion is processed inside thereof.
  • the terrace-shaped flat portion has a width of 1 to 20 ⁇ m and a length of 1 to 100 ⁇ m.
  • Carbon or boron is deposited on the terrace-like flat portion.
  • FIG. 18 shows an electron source support needle deposited with carbon or boron. When the electron source support needle deposited with carbon or boron is heated, the carbon or boron reacts with the underlying tantalum, titanium, zirconium, or nickel to form respective carbides or borides.
  • FIG. 19 shows carbide or boride formation and barrier layer formation. Rare earth hexaboride single crystal nanofibers are arranged, and carbon or platinum is deposited in a patch shape to produce an electron emission source tip.
  • an electron source in which a rare-earth hexaboride single crystal nanofiber is bonded to an electron source support needle is not damaged or deteriorated even when it is repeatedly flushed at a high temperature, and it is stable and durable.
  • a long-life cold cathode field emission electron source can be obtained.
  • Example 1 ⁇ Production of lanthanum hexaboride single crystal nanofiber (10-300 nm)> Based on the method for synthesizing rare earth hexaboride single crystal nanofibers disclosed in Patent Document 1, lanthanum hexaboride single crystal nanofibers were reaction-generated based on the chemical formula (1). Reaction was performed at 1150 degreeC and the lanthanum hexaboride single crystal nanofiber was grown on the silicon substrate.
  • FIG. 1 shows an electron micrograph of a lanthanum hexaboride single crystal nanofiber synthesized and grown starting from platinum particles on a silicon substrate. It was confirmed that it was growing vertically with respect to the substrate.
  • FIG. 2 shows a transmission electron micrograph. From this, it was confirmed that it was a complete single crystal nanofiber with no damage or defect. Further, from the diffraction pattern of this crystal, the crystal orientation was (001), and the end face of the single crystal nanofiber was confirmed to be a (001) crystal plane as shown in FIG. This is a crystal structure that is extremely suitable as an electron source material.
  • Example 2 ⁇ Production of lanthanum hexaboride single crystal nanofiber electron source>
  • an electron source using the single crystal nanofiber was fabricated.
  • Tungsten and platinum were used as the electron source support needle, and the tip of the support needle was processed into a flat shape as shown in FIG. 4 by a focused ion beam.
  • a single crystal nanofiber having a size of about 40 to 100 nm is selected and picked up, and the flat surface of the electron source support needle is The tip side was arranged so as to protrude.
  • Table 5 shows the material, size, crystal face of the end face, and material of the support needle of the nine types of electron sources produced.
  • FIG. 4 Carbon was deposited on the flat surface of the electron source support needle by vapor deposition on the arranged single crystal nanofibers (FIG. 4).
  • a photograph taken by a scanning electron microscope of the tip of the produced electron source is shown in FIG. (Example 3) ⁇ Cold cathode field emission characteristics of lanthanum hexaboride single crystal nanofiber electron source> The field emission characteristics of the lanthanum hexaboride single crystal nanofiber electron source were measured using a field emission characteristic measuring device.
  • FIG. 6 shows a current-voltage characteristic of current due to electrons emitted only by the voltage load of the electron source. When the current exceeds 2400 V, it rapidly increases and exponentially increases to become a large current.
  • Electrons are emitted at a low voltage and high current density.
  • lanthanum hexaboride as a single-crystal nanofiber, the potential gradient at the tip becomes extremely large, and electron emission from the tip is easy. It is shown that.
  • FIG. 7 compares the obtained current-voltage characteristics with those of an electron source (ZrO / W Schottky Emitter) in which zirconium oxide is coated on existing tungsten and tungsten needles that are said to have the highest practicality. Show. In the practical voltage range, the rare earth hexaboride cold cathode field emission electron source of the present invention has a much higher current density than the existing electron source, indicating that it is an unprecedented high performance electron source. ing.
  • FIG. 8 shows the results of continuous measurement of the emission current at a vacuum of 3 ⁇ 10 ⁇ 9 torr in order to investigate the stability of the prototype lanthanum hexaboride single crystal nanofiber electron source. The current fluctuation is 5% or less, which shows that the stability is extremely excellent.
  • the lanthanum hexaboride single crystal nanofiber electron source is a cold cathode field emission electron source that has far higher performance than existing ones, and also has stability and durability. It was confirmed that it was excellent and practical.
  • Example 4 ⁇ Preparation of electron source consisting of rare earth hexaboride single crystal nanofiber and rhenium electron source support needle>
  • an electron source support needle having the shape shown in FIG. 11 is fabricated using rhenium, and the single crystal nanofiber is placed on the terrace-like flat portion. Arranged.
  • a rare earth hexaboride single crystal nanofiber As a rare earth hexaboride single crystal nanofiber, a lanthanum hexaboride nanofiber having a diameter of about 40 nm is picked up from a substrate synthesized and grown by a chemical vapor deposition (CVD) method, and an electron source support needle is formed on a terrace-like flat portion. It was arranged along the central direction of the axis.
  • (A) of FIG. 12 is a scanning electron micrograph from the upper surface of the arrangement
  • (b) is a scanning electron micrograph from the side surface.
  • carbon or platinum is vapor-deposited on the nanofiber using an electron beam or ion beam to form a joining patch.
  • vapor deposition was performed using carbon.
  • the electron emission part of the rare earth hexaboride nanofiber electron source was produced.
  • this electron emission part By incorporating this electron emission part into an existing filament or electrode, it can be used as a thermionic emission type or a cold cathode field emission type electron source.
  • Tungsten is widely used as a filament and an electron emission source, and there are significant economic and production advantages using tungsten as an electron source support needle.
  • tungsten can react with the rare earth hexaboride and thus can react with the rare earth hexaboride nanofibers used in the present invention. Therefore, the reaction between tungsten and lanthanum hexaboride single crystal nanofibers and the effect of the barrier layer developed here were confirmed.
  • the tip of the electron source in which the lanthanum hexaboride single crystal nanofiber was bonded to the tungsten electron source support needle was heated at 900 ° C.
  • Lanthanum hexaboride reacts with tungsten support needles, and single crystal nanofibers are degraded and thinned by the reaction layer.
  • a scanning electron micrograph of the reaction layer at the junction between the tungsten support needle and the lanthanum hexaboride single crystal nano nanofiber is shown in FIG.
  • a reaction layer is formed in the single crystal nanofiber portion in contact with the tungsten electron source support needle, and the single crystal nanofiber is deteriorated and damaged.
  • a scanning electron at the tip of the electron emission source is formed by depositing chemically stable carbon on a tungsten electron source support needle and bonding a lanthanum hexaboride single crystal nanofiber on it.
  • a photomicrograph is shown in FIG. Scanning electron micrograph comparing the part of the carbon barrier layer after heating the tungsten electron source support needle with the carbon layer barrier and the tip of the lanthanum hexaboride single crystal nanofiber electron emission source at 900 ° C. before heating. Is shown in FIG.
  • Example 6 shows the results of the presence or absence of a reaction at a high temperature between the electron source support needle and the rare earth hexaboride lanthanum hexaboride in various structural examples.
  • the tungsten electron source support needle (Experiment Nos. 1 to 3) reacts with the rare earth hexaboride single crystal nanofiber even at 900 ° C. or lower, causing damage to the nanofiber.
  • the LaB 6 Table 7 shows the results of theoretically deriving materials that do not react at high temperatures.
  • the cold cathode field emission electron source using the rare earth hexaboride single crystal nanotube of the present invention and the electron source support needle is an unprecedented high-performance electron source, a transmission electron microscope, a scanning electron By incorporating it into an electron gun such as a microscope or an electron beam drawing apparatus, it is possible to improve the performance of these apparatuses and to dramatically improve the durability.

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  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Cold Cathode And The Manufacture (AREA)
  • Electron Sources, Ion Sources (AREA)
  • Solid Thermionic Cathode (AREA)

Abstract

L'invention porte sur une source d'électrons à émission de champ à cathode froide sur laquelle un hexaborure de terre rare a été appliqué et qui est empêchée d'être endommagée ou détériorée par des réactions chimiques, qui présente une excellente durabilité, et qui peut être utilisée longtemps. La source d'électrons à émission de champ à cathode froide émet des électrons au moyen d'un champ électrique élevé, et est caractérisée en ce qu'une nanofibre monocristalline d'un hexaborure de terre rare a été fixée à la surface d'une aiguille de support de source d'électrons. La source d'électrons à émission de champ à cathode froide est en outre caractérisée en ce que l'aiguille de support de source d'électrons est constituée d'une matière qui ne subit aucune réaction chimique au niveau de la section de liaison entre l'aiguille de support de source d'électrons et la nanofibre monocristalline d'un hexaborure de terre rare même lorsque la source d'électrons à émission de champ à cathode froide chauffe jusqu'à une température élevée.
PCT/JP2010/057018 2009-04-20 2010-04-20 Source d'électrons à émission de champ à cathode froide comprenant un hexaborure de terre rare Ceased WO2010123007A1 (fr)

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JP2011014529A (ja) * 2009-04-20 2011-01-20 National Institute For Materials Science 希土類六ホウ化物冷陰極電界放出型電子源
WO2014007121A1 (fr) * 2012-07-03 2014-01-09 独立行政法人物質・材料研究機構 Émetteur à effet de champ froid en hexaborure métallique, son procédé de fabrication et canon à électrons
EP2787522A4 (fr) * 2012-04-13 2016-04-27 Jianxin Yan Matériau d'électrode avec fonction de faible travail et stabilité chimique élevée
CN109804450A (zh) * 2016-10-13 2019-05-24 株式会社日立高新技术 电子束装置
WO2020158297A1 (fr) * 2019-01-30 2020-08-06 国立研究開発法人物質・材料研究機構 Émetteur, canon à électrons l'utilisant, et dispositif électronique
CN115410886A (zh) * 2022-09-15 2022-11-29 中国科学技术大学 一种场发射电子源及其制备方法
CN115410880A (zh) * 2022-09-15 2022-11-29 中国科学技术大学 一种低维结构电子源及其制备方法
CN115424908A (zh) * 2022-09-15 2022-12-02 中国科学技术大学 一种电子源发射器

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US9984846B2 (en) * 2016-06-30 2018-05-29 Kla-Tencor Corporation High brightness boron-containing electron beam emitters for use in a vacuum environment
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WO2014007121A1 (fr) * 2012-07-03 2014-01-09 独立行政法人物質・材料研究機構 Émetteur à effet de champ froid en hexaborure métallique, son procédé de fabrication et canon à électrons
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CN115410886A (zh) * 2022-09-15 2022-11-29 中国科学技术大学 一种场发射电子源及其制备方法
CN115410880A (zh) * 2022-09-15 2022-11-29 中国科学技术大学 一种低维结构电子源及其制备方法
CN115424908A (zh) * 2022-09-15 2022-12-02 中国科学技术大学 一种电子源发射器

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