WO2013152613A1 - 具有低逸出功和高化学稳定性的电极材料 - Google Patents

具有低逸出功和高化学稳定性的电极材料 Download PDF

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WO2013152613A1
WO2013152613A1 PCT/CN2012/087966 CN2012087966W WO2013152613A1 WO 2013152613 A1 WO2013152613 A1 WO 2013152613A1 CN 2012087966 W CN2012087966 W CN 2012087966W WO 2013152613 A1 WO2013152613 A1 WO 2013152613A1
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emitter
metal
electron
oxide film
electrode material
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PCT/CN2012/087966
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English (en)
French (fr)
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严建新
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吴江炀晟阴极材料有限公司
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Priority to EP12874231.9A priority Critical patent/EP2787522B1/en
Priority to US14/386,884 priority patent/US9812279B2/en
Priority to JP2015504841A priority patent/JP6458727B2/ja
Publication of WO2013152613A1 publication Critical patent/WO2013152613A1/zh

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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
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C16/00—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes
    • C23C16/22—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the deposition of inorganic material, other than metallic material
    • C23C16/30—Deposition of compounds, mixtures or solid solutions, e.g. borides, carbides, nitrides
    • C23C16/40—Oxides
    • 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
    • H01J1/13—Solid thermionic cathodes
    • H01J1/14—Solid thermionic cathodes characterised by the material
    • 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, ion-optical arrangement
    • H01J37/06—Electron sources; Electron guns
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J9/00—Apparatus or processes specially adapted for the manufacture, installation, removal, maintenance of electric discharge tubes, discharge lamps, or parts thereof; Recovery of material from discharge tubes or lamps
    • H01J9/02—Manufacture of electrodes or electrode systems
    • H01J9/022—Manufacture of electrodes or electrode systems of cold cathodes
    • H01J9/025—Manufacture of electrodes or electrode systems of cold cathodes of field emission cathodes
    • 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
    • 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
    • H01J2237/06308—Thermionic sources
    • H01J2237/06316—Schottky emission
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00—Stock material or miscellaneous articles
    • Y10T428/29—Coated or structually defined flake, particle, cell, strand, strand portion, rod, filament, macroscopic fiber or mass thereof
    • Y10T428/2913—Rod, strand, filament or fiber
    • Y10T428/2916—Rod, strand, filament or fiber including boron or compound thereof [not as steel]

Definitions

  • the present invention relates to an electrode material.
  • Instruments that use focused electron beams include imaging instruments such as scanning electron microscopy (SEM) and transmission electron microscopy (TEM) Manufacturing equipment such as electron beam etching machines (EBL) and chemical analysis instruments such as energy diffused X-ray energy spectrometers, electron energy loss spectrometers (EELS) ), and Auger electron spectrometer. In order to achieve higher performance, these instruments need to be equipped with an electron source with higher brightness and narrower electron beam energy divergence.
  • SEM scanning electron microscopy
  • TEM transmission electron microscopy
  • EBL electron beam etching machines
  • ELS electron energy loss spectrometers
  • Auger electron spectrometer Auger electron spectrometer
  • the requirement for brightness is to allow the analyzer to achieve a higher signal-to-noise ratio and to achieve higher yields in the etching machine; the requirement for narrow energy divergence is to allow the electromagnetic lens to be better focused, as it is now A certain color difference is unavoidable in terms of lens production level.
  • the brightness and energy divergence of an electron source depends both on the type of electron source material and on the way the electron beam is generated.
  • the bound electrons In order for electrons to be emitted from the surface of the electron source (emitter), we need to give the bound electrons enough energy to overcome the energy barrier between the emitter surface and the vacuum.
  • the height of this energy barrier is defined as the work function of the emitter material. If heating is used to excite bound electrons to overcome this barrier, this mode of emission is called thermal emission, and this source of electrons is called a source of hot electrons.
  • thermal emission this mode of emission
  • a source of electrons is called a source of hot electrons.
  • Typical low work function thermal emissive materials include borides, carbides and oxides of the second, third and fourth elements of the periodic table.
  • the energy barrier becomes so thin that the bound electrons can tunnel directly through the barrier to enter the vacuum, even without any thermal excitation.
  • This type of emission is referred to as field emission and such an emitter is referred to as a field emitter. Since no more heat is needed (more than 1800K Heating, among the three emission modes, the field emission has the highest brightness and the lowest energy divergence.
  • the lower the work function of the emitter material the thinner the energy barrier and the easier the electron tunneling. This results in a field emitter having a lower work function having higher brightness and lower energy divergence than a field emitter having a high work function.
  • an electron emitter Another important aspect of a practical application of an electron emitter is that the electron current density it emits must remain constant for a long period of time. Fluctuating, attenuating or increasing currents increase the design and operational complexity of the instrument in which it is applied.
  • An important factor that causes the emission current to change is the adsorption of the field emitter to the remaining gas molecules present in the incomplete vacuum. These adsorbed molecules change the work function of the surface, thereby changing the emission current density.
  • this adsorption effect is not as important as for low temperature field emitters. This is because the high temperature used in the thermal emission process can desorb any adsorbate from the surface of the emitter to keep the surface work function unchanged.
  • tungsten (W) materials with high work function (4.5 electron volts). When used to focus an electron beam instrument, high-event work limits the maximum brightness that can be achieved with an acceptable energy divergence.
  • tungsten (W) emitters react with residual gases, primarily hydrogen, in a vacuum. Its pre-attenuation platform period is usually shorter than 30 minutes when the vacuum is not as good as 1 ⁇ 10 -10 Torr; it is shorter than 5 hours when the vacuum is not good at 1 ⁇ 10 -12 Torr.
  • Schottky emitters typically emit electrons without attenuation when the vacuum is not good at 1 ⁇ 10 -9 Torr.
  • the oxide is more chemically inert relative to the metal of its constituent elements.
  • oxides themselves cannot be used to make low temperature field emitters because their conductivity is too low for electron transport.
  • a structure in which a low work function oxide film is coated on a conductive substrate can transmit electrons sufficiently to achieve low temperature field emission of the oxide surface.
  • this oxide layer In order to create a stable structure, this oxide layer must be firmly bonded to the conductive substrate to withstand the large electrostatic force generated by the voltage drawn during field emission. The vibration or peeling of the oxide film causes fluctuations and attenuation of the field emission current.
  • a particular substrate material only one or a few specific crystal faces and a specific oxide form a strong bond.
  • the needle-shaped substrate needs to be formed into a single crystal along that specific crystal orientation, so that the surface of the needle tip can firmly bond the upper oxide film.
  • Such a structure has the advantage of converging the beam shape at the same time because the electron emission is concentrated on that particular crystal face, so that only that crystal face has a low work function.
  • people found zirconium The oxide bias of Zr is bonded to the (100) surface of W, so the work function of the W (100) plane is selectively reduced.
  • a tip is a tip of a (100) plane W
  • a field emitter having a low work function 2.6 electron volts
  • W Oxide is not used to reduce the surface work function of the top surface of the tip.
  • Alkaline earth oxides, rare earth oxides, cerium oxide, cerium oxide are stable compounds and are more specific than ZrO and W Oxides have a lower work function. According to the conventional techniques known, no substrate material forms a stable bond with these oxides, so that we can make a lower work function and a higher surface inertia based on these oxides. Field emitter.
  • An object of the present invention is to provide an electrode material having low work function and high chemical stability, comprising an emitter capable of conducting electricity and an electron emission layer disposed on a surface of the emitter, wherein the emitter is composed of The compound substrate is made of a material, and the electron-emitting layer is made of an oxide film.
  • the compound substrate may have various shapes such as a plate shape, a needle shape, a column shape, or a block shape, and the compound substrate has a specific crystal face which can be firmly bonded to the oxide film.
  • the material of the compound substrate is selected from the group consisting of metal borides, metal nitrides or metal carbides, and the metal elements thereof are calcium, lanthanum, cerium, lanthanum, cerium, lanthanide, cerium, titanium, zirconium. A combination of one or more of the sputum.
  • the metal boride may be selected from a single crystal hexaboride of calcium, lanthanum, cerium, lanthanum, cerium or lanthanide, and the crystal orientation of the metal boride is lattice (100), (110) Or ( 111 ) direction.
  • the metal carbide may be selected from a single crystal single carbide of ruthenium, titanium, zirconium or hafnium, and the crystal orientation of the metal carbide is a lattice (100) ), (110) or (111) direction.
  • the oxide film is composed of a metal oxide
  • the metal element other than the oxygen element in the oxide film is selected from the group consisting of calcium, strontium, barium, strontium, cerium, lanthanide, cerium, titanium, zirconium. A combination of one or more of the sputum.
  • the metal element in the compound substrate tends to be the same as the metal element in the oxide film, such that the component elements other than the oxygen element in the oxide film can be directly provided by the emitter itself, thereby Eliminate additional evaporation sources or accumulate source structures.
  • the emitter tends to be needle-shaped, and the oxide film layer is disposed at the needle tip position of the needle-shaped emitter.
  • the top end of the acicular emitter forms a top platform perpendicular to the axial direction of the acicular emitter, and the oxide film layer should cover at least the top platform region.
  • the tip of the acicular emitter should have a sufficiently small size to produce the strong electric field required for the field emission mechanism, and the axial direction of the tip should be parallel to a particular crystal orientation, and the crystal plane perpendicular to this crystal orientation can be oxidized.
  • the film is firmly bonded, and the crystal face is the crystal face of the top platform.
  • the top end of the acicular emitter forms a top cylinder axially parallel or coincident with the axial direction of the emitter, and the top surface of the top cylinder is a top platform perpendicular to the axial direction of the emitter.
  • the oxide film covers at least the top platform region.
  • the arrangement of the top cylinder can concentrate the high electric field on the top platform. This electric field distribution is advantageous for concentrating the electron emission in the top platform region and reducing the structural accumulation of the material in the vicinity of the top platform to the top platform region, thereby further improving The stability of electron emission.
  • Another object of the present invention is to provide a vacuum field electron emitter, comprising an insulating block, two metal columns respectively piercing the insulating block, and a filament welded at both ends to the ends of the two metal columns. And a needle-shaped substrate welded to the middle of the filament; a top of the needle-shaped substrate forming a needle tip, the vacuum field electron emitter further comprising a cylindrical emission disposed at a tip position of the needle-shaped substrate by a bonding layer a block, and an electron emission layer disposed on top of the cylindrical emission block; the cylindrical emission block has a cylindrical area, and a top side of the cylindrical area is contracted toward the axial direction of the emission block to form a tapered surface a top portion of the tapered region forming a top platform perpendicular to an axial direction of the emitter block, the electron emission layer being disposed on the top platform; the emission block being made of a compound substrate, the electron
  • the material of the emissive layer is an oxide film.
  • the material of the emission block is selected from the group consisting of metal borides, metal nitrides or metal carbides, and the metal elements thereof are calcium, strontium, barium, strontium, strontium, lanthanide, cerium, titanium, zirconium and hafnium. a combination of one or more of them.
  • the oxide film is composed of a metal oxide
  • the metal element other than the oxygen element in the oxide film is selected from the group consisting of calcium, strontium, barium, strontium, strontium, lanthanide, cerium, titanium, zirconium and hafnium. a combination of one or more of them.
  • the acicular substrate is made of a high melting point conductive material, and the high melting point conductive material is selected from the group consisting of carbon, tungsten, tantalum, niobium or molybdenum.
  • the bonding layer is composed of carbon, platinum or tungsten elements.
  • a top cylinder axially parallel or coincident with the axial direction of the emitter is formed on the tapered surface of the emission block, and a top surface of the top cylinder is a top platform perpendicular to the axial direction of the emission block.
  • a third object of the present invention is to provide a method for preparing a top cylinder at the tip of a needle or columnar emitter made of metal hexaboride, comprising the steps of:
  • the top end of the emitter forms a hemispherical surface, the top end of the hemispherical surface is a (100) crystal plane;
  • the top when the hemispherical surface corrodes with corrosive gases, the top (100 The etching speed of the crystal face is slower than the etching speed of the other crystal faces, and when the hemispherical surface forms a cylindrical shape perpendicular to the axial direction of the emitter, the applied positive voltage and the corrosive gas are removed, and the top cylinder is Has been formed.
  • the etching gas described in the above method is oxygen, nitrogen or water vapor.
  • a fourth object of the present invention is to provide another vacuum field electron emitter comprising an insulating block, two metal pillars respectively piercing the insulating block, and respectively ending with the ends of the two metal pillars
  • Two filaments welded, two graphite heating plates welded between the two filaments, and a block-shaped base body sandwiched between the two graphite heating plates;
  • the central portion of the block-shaped substrate is convex upward a needle-like emitter having a tip end, the tip position of the needle-shaped emitter forming a top platform perpendicular to an axial direction of the needle-shaped emitter
  • the vacuum field electron emitter further comprising a needle-shaped emitter disposed a top electron-emitting layer;
  • the needle-shaped emitter is made of a compound substrate, and the electron-emitting layer is made of an oxide film.
  • the material of the block substrate and the acicular emitter is selected from the group consisting of metal borides, metal nitrides or metal carbides, and the metal elements thereof are calcium, strontium, barium, strontium, strontium and lanthanide. a combination of one or more of cerium, titanium, zirconium and hafnium.
  • the oxide film is composed of a metal oxide, and a metal element other than the oxygen element in the oxide film is selected from the group consisting of calcium, strontium, barium, strontium, strontium, lanthanide, cerium, titanium, zirconium, and A combination of one or more of the sputum.
  • a fifth object of the present invention is to provide a method of providing an oxide thin film layer on a top stage of a needle-like or columnar emitter, comprising the steps of:
  • the applied voltage is stopped, and the oxide film layer is already disposed on the top platform of the emitter.
  • step a is achieved by heating the emitter in an oxygen-containing gas.
  • step a can also be achieved by depositing an oxide on the adjacent surface of the top platform using a thin film deposition technique.
  • step b is accompanied by heating to a temperature which increases the mobility of the oxide, and step b is completed to stop the heating.
  • the above method further comprises the step d after the completion of the step c :
  • the emitter is heated to a temperature below the evaporation point of the oxide film to achieve a firm bond between the oxide film layer and the top platform.
  • step d It may also be a method of maintaining the emitter at a certain oxygen-containing gas pressure for a period of time with or without heating to achieve a firm bond of the oxide film layer to the top platform.
  • the electrode material of the present invention can be used for an electron source capable of providing electrons, and the electrode material is suitable for emitting electrons by field emission.
  • the electrode material is accompanied by heating during operation, but the heating temperature should be lower than the temperature at which the electrode material can emit electrons by thermal emission.
  • the electrode material of the present invention can be used as a vacuum electron source for an electron beam apparatus, an electron injection electrode of an organic or inorganic light emitting diode, and an organic or inorganic solar cell, an organic or inorganic transistor, and a cathode of an electrochemical device.
  • the electron beam apparatus includes a scanning electron microscope, a transmission electron microscope, a scanning transmission electron microscope, an electron beam etching machine, and an energy diffusion x Ray energy spectrometer, electron energy loss spectrometer, etc.
  • the invention has the following advantages:
  • the electrode material of the present invention has a lower work function when emitting electrons, and the oxide film layer is more strongly bonded to the emitter and has higher chemical stability.
  • the vacuum field electron emitter of the present invention can realize electron emission with high current density for a long time and keeping current density unchanged.
  • FIG. 1 is an overall structural view of a vacuum field electron emitter of Embodiment 1;
  • Figure 2 is an enlarged view of the needle tip of Figure 1;
  • Figure 3 is a plan view of Figure 2;
  • Figure 4 is an enlarged view of the top platform of Figure 2;
  • Figure 5 is an enlarged view of a needle tip of the vacuum field electron emitter of Example 2.
  • Figure 6 is a view showing the overall structure of a vacuum field electron emitter of Embodiment 3.
  • Figure 7 is a flow chart for fabricating the vacuum field electron emitter of the present invention.
  • FIG. 8 is a flow chart showing an oxide thin film layer disposed in a vacuum field electron emitter of the present invention.
  • Figure 9 is a structural view of an electron beam apparatus using the vacuum field electron emitter of the present invention.
  • the oxide thin film layer of the present invention can be firmly bonded to a metal boride, carbide or nitride compound substrate, so that long-time high current density electron emission can be realized without maintaining current density.
  • the compound substrate of the present invention has a better bonding strength with the oxide film layer than the high-temperature metal substrate used in the conventional method, the reason for this is not fully understood, but at least partly due to the oxide film layer.
  • the fact that the atoms of the compound substrate are bonded by covalent bonds allows the oxide film layer to have better compatibility with the compound substrate.
  • the second possible reason is that when both the oxide film layer and the compound substrate are composed of the same metal element, the lattice size of the oxide film layer and the compound substrate should be similar, thereby reducing the poor interface matching between the two. .
  • the reason why we tend to make the oxide film layer and the compound substrate have the same metal composition is that, in this case, the oxide film layer can be directly reacted with oxygen and the compound substrate to realize the compound base. The adhesion of the surface of the material, which brings convenience to the manufacture and operation of the electron gun.
  • the metal component contained in the oxide film layer having a low work function is usually low in melting point and highly reactive. Therefore, it is very difficult to fabricate an emitter substrate, an evaporation source or a diffusion accumulation source using the elemental form of these metal components.
  • the corresponding boride, carbide or nitride of these metals are high melting point, high mechanical strength and low reactivity, and they can be directly used as a suitable emitter substrate. Because of this, we can simply select any metal oxide with low work function as the electron-emitting layer of the emitter, without being limited by metal selection. It is further claimed that the electrode material of the present invention can be used as a vacuum electron emission source in addition to a needle-like structure.
  • the present invention can be used as a plate or a block for organic use.
  • an electron injection electrode of an inorganic light emitting diode, an organic or inorganic solar cell, an organic or inorganic transistor, and a cathode of an electrochemical device can be used as a plate or a block for organic use.
  • the vacuum field electron emitter 100 of the present embodiment is a base pin 104 soldered to the filament 106.
  • filament Both ends of the 106 are welded to the two metal posts 108, respectively.
  • the two metal posts 108 are mechanically joined together by an insulating block 110 and provide electrical insulation.
  • Base needle 104 The tip 102 has a small radius of curvature which should be less than 10 microns and greater than 100 nanometers.
  • the filament 106 is used to heat the base needle in a Joule heating manner by a certain current.
  • the base pin 104 is made of a high melting point conductive material. These materials include, but are not limited to, C, W, Re, Ta, and Mo.
  • Base needle 104 The material should have a higher melting point than the cleaning temperature and use temperature of the vacuum field electron emitter. In a specific example, the cleaning temperature and operating temperature are expected to be as high as 1300K. Base needle 104 It can be either single crystal or polycrystalline. Its tip 102 can be of any crystal structure orientation.
  • FIG. 2 shows an enlarged view of the needle tip 102 of the base needle 104, the base needle 104 A platform is cut out and two additional sections are built on top of the platform: a cylindrical launch block 200 and a bond layer 208.
  • the launch block 200 is required to have at least the following three parts: a top platform 202 , a tapered area 204 and a cylindrical area 206 .
  • At least the top platform 202 is covered by an oxide film layer for emitting electrons.
  • the radius of the top platform 202 tends to be less than 500 Nano, more inclined to less than 100 nanometers, most inclined to less than 10 nanometers.
  • the top platform 202 is comprised of several atoms or even a single atom.
  • Cylindrical area 206 The radius should be greater than or equal to the radius of the top platform 202.
  • the cylindrical area 206 Can be used to form a new top platform and a new cone area. But the cylinder area 206 The length should not exceed a critical value. Above this value, the vibration becomes severe and thus affects the stability of the emission pattern. Those skilled in the art should readily recognize that this critical length value is associated with the launch block 200. The material and radius vary.
  • Figure 3 is a top view of Figure 2 to help better visualize the three components of the launch block 200.
  • Launch block 200 It tends to be made of conductive metal borides, carbides, or nitrides.
  • the metal element includes a combination of one or more of the following elements: a second group element comprising Ca, Sr and Ba; Y , and the third family of elements of the lanthanide; the fourth group of elements containing Zr , Hf and Th .
  • the emission block 200 is composed of Ca , Sr , Ba , Y , La , Ce Hexaboride or a single carbide of Ti, Zr, Hf, Ta, Th.
  • Launch block 200 It tends to be single crystal.
  • the axial direction of this single crystal is perpendicular to the crystal plane which can selectively bond the selected oxide film layer. In some instances, this single crystal orientation tends to be ⁇ 100> ⁇ 110> or ⁇ 111> direction.
  • a polycrystalline emitter block with a single grain at the tip of the tip naturally plays the same role.
  • Bonding layer 208 should be electrically conductive and its radius should be greater than or equal to the radius of emitter block 200. Bonding layer 208 The materials used should be those materials which are so high that the cleaning and use temperatures of such vacuum field electron emitters do not react with either the emitter block 200 nor the matrix needle 104. When bonding layer 208 When there is a slow reaction between the bonded portion and the bonded portion, the thickness of the bonding layer 208 should be greater than the loss generated during the entire lifetime of the vacuum field electron emitter. In some examples, bonding layer 208 can be composed of C , W or Pt is made. Bonding layer 208 It can be formed by some methods such as, for example, selective deposition or by degrading a paste containing a desired component.
  • the emitter block 200 and the base needle 104 are used with a mechanical manipulator. Electron beam induced deposition or ion beam induced deposition can be used to deposit the bonding layer 208 when in close proximity. Epoxy droplets can also be used to connect the emitter block 200 to the base needle 104. . The epoxy droplets can then be changed to a C-bonded layer by vacuum thermal carbonization.
  • the oxide film layer 402 is coated over the top stage 202 for use as an electron emission layer.
  • the element other than the oxygen element in the oxide thin film layer contains a combination of one or more of the following elements: a second group element containing Ca, Sr, Ba; or a group containing Sc, Y and a lanthanoid element a tri-family element; or a fourth-element element that contains Zr, Hf, and Th.
  • the oxide film layer 402 tends to have the same metal composition as the emitter block 200 because it can have a small interface mismatch and can directly form the oxide film by reacting the emitter block 200 with oxygen.
  • the oxide film layer 402 and the underlying emitter block 200 can form a small interface matching difference despite the difference in the component metals, and the film can be firmly bonded over the emitter block 200
  • the oxide film layer 402 can also be used.
  • the emitter block 200 uses a different component metal.
  • La and Ce have similar size and chemistry. Therefore, it is obvious that we can attach a CeO x (x is unknown) film layer on LaB 6 or a LaO x (x is unknown) film layer on CeB 6 . Also, it is apparent that we can attach a mixed oxide film layer such as La x Ce y O on a mixed compound substrate such as La z Ce ( 1 - z ) B 6 .
  • any combination can be used as long as the hybrid combination provides a good interface combination.
  • the difference in interface matching may be greater than if they had different elements.
  • the metal element in the oxide thin film layer 402 may be more likely to be used and the metal contained in the emission block 200. Elements with different elements.
  • the top stage 202 of the emitter block 200 tends to be completely coated with an oxide film having at least a monolayer thickness.
  • the thickness of the oxide film layer 402 should not exceed a critical value. That is, after exceeding this critical thickness, the structural stability of such a vacuum field electron emitter is deteriorated or the electric resistance of the oxide thin film layer 402 is increased to affect the electron emission performance.
  • the transmitting block 500 in this embodiment is composed of at least four parts: a top platform 502, a top cylinder 504, a tapered surface area 506, and a cylindrical surface area 508. Except for the top cylinder 504, the rest of the transmitting block 500 of this embodiment should have the same structure and function as the tip 102 of the embodiment 1.
  • the top cylinder 504 is used to reduce the electric field strength of the tapered region 506 to concentrate the high electric field on the top platform 502.
  • the resulting electric field distribution facilitates concentration of electron emission to the top platform 502 and reduces material buildup of the material on the tapered surface 506 onto the top platform 502.
  • Such a structure further enhances the emission stability of the vacuum field electron emitter of the present embodiment.
  • the emitter block structure with the top cylinder of this embodiment can be fabricated based on the principle that the etching speeds are different between crystal planes of different orientations in the compound substrate emitter. For example, when a gas containing oxygen is used as an etchant, the (100) crystal plane of the metal hexaboride structure has a lower corrosion rate than the other crystal faces.
  • a specific method for forming such a structure includes the steps of: first, forming a (100) crystal plane on the surface of the emitter tip in a vacuum vessel; and then applying a positive on the emitter relative to an adjacent electrode on the opposite side. The voltage and simultaneously introduce an oxygen-containing gas into this vacuum.
  • the top platform 502 of the launch block is a (100) crystal plane
  • the top platform 502 will have the slowest corrosion rate.
  • a higher material removal rate experienced by a crystal face that is not (100) in the periphery will form a top cylinder 504.
  • a (100) crystal plane is formed on the tip end surface of the metal hexaboride, and techniques such as field assisted hydrogen etching, vacuum field evaporation, and thermal annealing can be selected.
  • a top platform 502 on the top cylinder 504 is fabricated using the following parameters: the applied voltage is between 2000V and 8000V, and the corrosive gas pressure is 1 ⁇ 10 -8 Torr ⁇ 1 ⁇ Between 10 and 5 Torr, the corrosive gas is oxygen or water and the temperature is room temperature. From the above, it will be apparent to those skilled in the art that the above-described top cylinder 504 can be formed by selecting different voltages, etchant types, pressures, temperatures, and operating times using conventional techniques.
  • This embodiment provides another vacuum field electron emitter which also has an insulating block, two metal posts disposed on the insulating block, and a filament welded to the two metal posts.
  • the vacuum field electron emitter of the present embodiment The 600 further includes a bulk emitter 601 which is divided into two parts: an emitter tip 602 and a base 604 that are raised in the middle of the upper surface of the block emitter 601. Two filaments 608 The ends are respectively welded to the heating plate 606, and the block emitter 601 is disposed between the two heating plates 606.
  • the heating plate 606 serves two purposes: one is a mechanical support for the bulk emitter 601; Another function is to generate heat when passing current.
  • the heating plate 606 tends to be made of graphite.
  • the block emitter 601 It tends to be made of conductive metal borides, metal carbides or metal nitrides.
  • the metal constituent elements of these compounds include: a second group element containing Ca, Sr, Ba; or contain Sc, Y. And the third family of elements of the actinide; or the fourth family of elements that contain Zr, Hf, and Th; or a combination of these elements.
  • the bulk emitter 601 consists of Ca , Sr , Ba , Y , La, Ce hexaboride or a single carbide of Ti, Zr, Hf, Ta, Th.
  • Bulk emitter 601 It tends to be a single crystal, and the crystal axis is perpendicular to those crystal faces that need to be selectively bonded to the selected oxide film layer. In some instances, the crystal axis tends to be ⁇ 100>, ⁇ 110> Or ⁇ 111> direction. Polycrystalline bulk emitters having a single crystal of the emitting tip can also be used to achieve the same purpose.
  • the tip structure of the emitter tip 602 tends to be as shown in Figure 2 and Figure 5.
  • the launch tip 602 can be fabricated using micromachining. For example, a single crystal can be first cut into the shape of the substrate 604, and then a focused ion beam (FIB) Milling to remove material around the substrate 604 until an emitter tip 602 is formed.
  • FIB focused ion beam
  • the material and shape of the emitter, as well as the material and size of the oxide film layer, can affect the use of the resulting field electron emitter product.
  • This example provides a plurality of operational examples of vacuum field electron emitters prepared in accordance with the present invention to demonstrate that the products of the present invention are capable of achieving stable operation for longer periods of time at higher gas pressures than prior art techniques.
  • the Applicant tested an electron field emitter product: an extraction voltage of less than 800 V, an emission current of less than 3 ⁇ A, a heating temperature of less than 1000 K, a current fluctuation of less than 5%, and less than 3
  • the field electron emitters are stable for more than 100 hours under a vacuum of 10 -9 Torr;
  • the Applicant tested an electron field emitter product: an extraction voltage of less than 500 volts, an emission current of less than 1 microamperes, a heating temperature of less than 800 K, a current fluctuation of less than 5%, and a worse than
  • the field-induced electron emitter is stable for more than 30 hours under a vacuum of 2 ⁇ 10 -10 Torr;
  • the Applicant tested an electron field emitter product: an extraction voltage of less than 1000 V, an emission current of less than 10 ⁇ A, a heating temperature of less than 1100 K, a current fluctuation of less than 5%, and a worse than
  • the field-induced electron emitter is stable for more than 60 hours under a vacuum of 3 ⁇ 10 -9 Torr;
  • the Applicant tested an electron field emitter product: an extraction voltage of less than 700 V, an emission current of less than 5 ⁇ A, a heating temperature of less than 700 K, a current fluctuation of less than 10%, and a worse than
  • the field electron emitters were stable for more than 40 hours under a vacuum of 1 ⁇ 10 -10 Torr.
  • This embodiment provides a method and flow for making a vacuum field electron emitter of the present invention.
  • a length of the base wire is welded to the middle of a filament structure. Both ends of the filament structure are respectively welded to a metal lead post.
  • the lead post is mounted in an insulating block (see Figure 1).
  • the top of the base wire is invaded into an etchant solution and a voltage is applied relative to an adjacent Pt ring.
  • the type of corrosive agent, the concentration, and the type of applied voltage vary with the type of the base wire.
  • the base wire is corroded into a matrix needle by an electrochemical etching process.
  • the tip of the substrate is coated with a protective layer to prevent the tip material from reacting with the emitter material to be placed on the tip of the substrate.
  • the protective layer described above is made of C.
  • a variety of techniques can be used to coat the substrate with such a protective layer, such as chemical vapor deposition, thermal degradation of epoxy resin, or charged particle beam induced deposition.
  • a parallel step 708 is used to make the shot block.
  • a method of specifically fabricating an emission block includes the steps of: taking a single crystal of a desired emission block material; if the single crystal does not satisfy a desired three-dimensional size, the single crystal is processed to have a width by a focused ion beam milling technique.
  • step 720 the prepared emitter block having the desired size is placed adjacent to the base needle tip via a protective layer such that the height of the emitter block coincides with the axial parallel or alignment of the base pin. Accurate alignment can be achieved using, for example, an electrically driven mechanical operator.
  • a bond layer is applied over the joint of the emitter block and the base tip to mechanically secure the structure and provide electrical conduction.
  • the protective layer may be omitted in step 716 when the bonding layer is sufficiently thick and the emitter block is not in direct contact with the substrate pin material.
  • the top of the firing block is machined into a tip having a small radius of curvature. Preferably, the tip has a radius of curvature between 5 nanometers and 200 nanometers.
  • the top of the launch block is a top platform that has an area that tends to be less than 400 square nanometers. Techniques that can be used to make this platform include: focused ion beam milling, field assisted hydrogen, nitrogen or oxygen corrosion, vacuum or inert gas field evaporation, and thermal annealing.
  • the emitter block tends to be flush with the crystal orientation perpendicular to the closely packed atomic planes, including the ⁇ 100>, ⁇ 110> and ⁇ 111> directions.
  • an oxide film layer is formed on the top platform of the emitter block as an electron emission layer.
  • Such an oxide thin film layer can be formed by various techniques. In an example where MO x is exemplified, where M is the desired metal element and x is an unknown stoichiometry, by heating a source material containing M to the evaporation temperature, the evaporation source is used to provide M-containing elements. Vapor, oxygen may be included in the source material or may be introduced as additional oxygen.
  • oxygen can be introduced to form MO x during M vapor deposition, or M layer can be converted into MO x layer by a subsequent oxidation process.
  • a method of diffusing MO x from the portion other than the vacuum field electron emitter through the surface to the tip platform can also be used to form such an oxide film layer. A detailed description of this method is shown in the block diagram of FIG.
  • this embodiment provides an example for forming an oxide film layer on the top platform of the emitter block and for use in a charged particle instrument.
  • an electron field emitter having an emitter block as depicted in Fig. 2 or Fig. 5 is fabricated and a top platform is fabricated on the tip end of the emitter block.
  • the emitter block in this embodiment tends to be a MB 6 material, that is, a hexaboride of the metal element M.
  • the metal element M tends to be Ca, Sr, Ba, Y, La, or Ce.
  • the MB 6 emitter block is oriented in the crystal ⁇ 100> direction.
  • the top platform is the (100) crystal plane of the hexaboride MB 6 .
  • the electron field emitter is mounted into a charged particle instrument as an electron emission source, and the instrument chamber is then evacuated.
  • the vacuum in the vacuum environment corresponding to the field electron emitter of the present invention should be better than 1 ⁇ 10 -7 Torr.
  • the firing block is heated to a cleaning temperature that is high enough to desorb the vaporizable material adsorbed on the surface of the electron field emitter, which is substantially water and organic molecules. In one example, this cleaning temperature does not exceed 1000K. It should be appreciated that the cleaning temperature should not exceed the temperature at which the oxide of the component metal begins to evaporate. In one example, the cleaning temperature does not exceed 1300K, or more preferably does not exceed 1200K.
  • step 816 it is detected whether the desired oxide film layer is formed on the top stage of the emitter block.
  • One result of the formation of the oxide film layer is a reduction in the work function of the top stage. Therefore, any means that can be used to determine the value of the work function or the change in work function can be used to carry out this test. For example, it can be recorded that the emission current changes with different extraction voltages to form an IV curve.
  • a so-called fowler-nordheim plot can be made.
  • the slope of this plot can then be used to determine the work function of the emitter.
  • the work function can be determined prior to the oxide coating process and used to compare the work function values obtained after a particular coating process.
  • Another method used in the measurement method is that the field emission current increases sharply as the work function of the emitter decreases.
  • the emission current corresponding to a fixed extraction voltage can be recorded before any coating process. After a specific process, the emission current corresponding to the same extraction voltage can be measured again.
  • Another method is based on the phenomenon that the selective coating of the oxide film layer on the top of the emitter will only result in a reduction in the work function on the top platform, resulting in a convergent field emission pattern having a divergence angle of less than 30 degrees. .
  • the field emission pattern can be recorded using an imaging device such as a fluorescent screen.
  • an imaging device such as a fluorescent screen.
  • the emitter block can be heated to a reaction temperature either after oxygen exposure or during oxygen exposure to ensure a reaction between M and O.
  • the reaction temperature should be lower than the evaporation point of the oxide MO x (x unknown) at the pressure used for the oxygen-containing gas.
  • the reaction time should be sufficient for the oxide MO x to be formed. In general, higher oxygen exposure pressures require lower reaction temperatures and shorter reaction times. In one example, the oxygen pressure used is between 1 x 10 -7 Torr and 1 atmosphere, the reaction temperature is between 600K and 1400K, and the reaction time is between 10 seconds and 5 minutes. Those skilled in the art will readily recognize that other combinations of oxygen-containing gas species, gas pressure, reaction temperature, and reaction time are considered to be within the scope of the present invention.
  • the oxide has been formed on the surface of the emitter block during preparation or processing before the emitter block is installed into the vacuum chamber.
  • step 820 becomes an optional step rather than a required link.
  • a process of diffusing the oxide is performed to selectively form an oxide film layer on the top stage.
  • the surface oxide of the emitter block can diffuse to the (100) face of MB 6 , which in this embodiment is the face of the top platform.
  • the voltage applied to the emitter block is negatively biased relative to an adjacent electrode, and it is capable of producing an emission current between 10 nanoamperes and 10 microamps.
  • the emitter can help this diffusion process and thus the time required for the (100) plane to completely coat the oxide can be shorter.
  • this temperature accompanying heating is between 600K and 1000K.
  • the oxide can be exposed on the (100) surface by exposing the emitter to an oxygen-containing gas for voltage-free aging treatment. Completely covered.
  • the oxygen pressure is between 1 x 10 -8 Torr and 1 x 10 -9 Torr, and the aging time is between 20 hours and 60 hours.
  • step 816 After the above oxide coating process, it is again passed to step 816 to detect whether the oxide film layer has been completely formed. Step 816, step 820 and step 824 should be recycled until it is confirmed that the oxide film layer has been completely formed. In some cases, such as when a screen is used to view the field emission pattern, step 816 can be performed concurrently with step 824. If the oxide film layer is confirmed to have formed, then go to the next step 828. In step 828, a voltage is applied to the electron field emitter to produce a desired field emission current. The field electron emitters tend to operate at temperatures not exceeding 400 K, since low temperature operation can result in the narrowest energy divergence.
  • step 832 the emission volatility of the electron field emitter is examined. This operation can be performed simultaneously with step 828 when the field emission current is monitored by the ammeter. During operation, contaminants or excess oxidizing species may form on the surface of the oxide film layer, causing fluctuations in emission current.
  • the emission current fluctuation is defined as the variation of the emission current over the average of the upper emission current in one minute. In one example, 10% is used as the emission fluctuation threshold.
  • step 812 When the emission current fluctuates beyond this threshold, it is directed to step 812 where the electron field emitter is heated to achieve a clean temperature to restore stable emission characteristics.
  • step 832 stable electron emission that can be practically applied by the electron beam instrument can be realized.
  • FIG. 9 the electron beam apparatus in this embodiment is a field emission scanning electron microscope (SEM) 900.
  • the field electron emitter 100 of this embodiment is selected as shown in FIG. 1
  • the field electron emitter shown is mounted in a vacuum chamber 924 of the SEM, the two filament current pin posts of the emitter being connected to the exterior of the cavity 924.
  • One filament power supply 904 Used to provide the heating current used by the filament.
  • An extraction electrode 916 is placed adjacent the tip end of the field electron emitter 100 to enable the emitter block to release electrons. The extraction electrode 916 is introduced into the terminal and the cavity through the vacuum The outside world of 924 is connected.
  • An extraction voltage source 908 is used to maintain the extraction voltage difference between the field electron emitter 100 and the extraction electrode 916. From the emitter 100 by applying an extraction voltage An electron beam 912 is generated. A scanning and focusing system 920 is used to focus the electron beam 912 into a small electron probe and scan the surface of the sample 936 with the probe. Sample 936 It is mounted on a mobile station 932 that is used to help observe the sample. A signal detector 928 is mounted adjacent to sample 936 for collecting signals generated by the interaction between the electron probe and the sample. a vacuum pump The 944 is used to create the vacuum required within the cavity 924. An oxygen source 940 is used to introduce an oxygen-containing gas at a desired pressure within the chamber 924. Oxygen-containing gas can also be reduced by vacuum pump 944 The pumping force is supplied by the surrounding environment or by leakage to the outside of the cavity 924. Thus, in this example, oxygen source 940 is optional and not required.

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Abstract

本发明公开了一种电极材料。此电极材料易于电子注射且不会和接触物质反应。此电极材料的结构包括一个导电的化合物基材，以及覆设在这个化合物基材表面的氧化物电子发射层。本发明的氧化物电子发射层能够与作为发射基体的化合物基材牢固结合，且具有低逸出功和高化学稳定性。

Description

具有低逸出功和高化学稳定性的电极材料
技术领域
本发明涉及一种电极材料 。
背景技术
使用聚焦电子束的仪器包括成像仪器，比如扫瞄电子显微镜（ SEM ）和透射电子显微镜（ TEM ）；制造仪器比如电子束刻蚀机器（ EBL ）以及化学分析仪器比如能量漫散 X 射线能谱仪，电子能量损失能谱仪（ EELS ），和俄歇电子能谱仪。为了实现更高的性能，这些仪器需要配备一个亮度更高并且电子束能量发散更窄的电子源。关于亮度的要求是为了让分析仪器实现更高的信噪比以及让刻蚀机器实现更高的产出率；对于窄能量发散的要求是为了让电磁透镜能更好的聚焦，因为就现在的透镜生产水平而言，一定的色差是无法避免的。一个电子源的亮度和能量发散既取决于电子源材料种类又取决于电子束的产生方式。
为了让电子能从电子源（发射体）表面发射出来，我们需要给予束缚的电子足够的能量去克服发射体表面和真空之间存在的能量壁垒。此能量壁垒的高度被定义为发射体材料的逸出功。如果加热被用来激发束缚电子去克服这个壁垒，这种发射模式被称为热发射，这种电子源被称为热电子源。当发射体材料的逸出功较低的时候，则需要较低的温度来实现同样程度的热激发。这样就能同时提高发射的亮度和降低能量发散。典型的低逸出功热发射材料包括周期表中第二，第三，第四族元素的硼化物，碳化物和氧化物。当加热到同样的温度的时候，这些低逸出功材料相对于传统的热发射体材料钨（ W ）能发射出更高的电流密度，因为钨（ W ）具有高的逸出功。当我们在这个发射体上相对于一个邻近的电极加一个负电压的时候，那个能量壁垒会因为肖特基效应随着电场强度的增强而降低。当加热仍用来激发电子的时候，壁垒高度的降低会帮助电子更容易的逃离发射体表面。这个发射模式被称为肖特基发射或者场增强型热发射。此发射体被称为肖特基发射体。当发射体材料为 ZrO ／ W （逸出功约 2.6 电子伏）的时候，肖特基发射体比热发射体具有更高的亮度和更低的能量发散。当我们继续增加所加电场强度的时候，能量壁垒会变的如此之薄以至于束缚电子能够直接隧穿过壁垒从而进入真空，甚至不需要任何的热激发。此种发射模式被称为场发射，此种发射体被称为场发射体。由于不再需要高温（超过 1800K ）加热，在三种发射模式当中，场发射具有最高的亮度和最低的能量发散。在同样的电场强度下，发射体材料的逸出功越低，能量壁垒就越薄，电子隧穿就越容易。这就造成了相较于高逸出功的场发射体，低逸出功的场发射体具有更高的亮度和更低的能量发散。
对于一个实际应用的电子发射体来说，另一个重要的方面是它所发射的电子电流密度必须在一个长时间内能保持不变。波动的，衰减的或者渐增的电流都会增加应用它的仪器的设计和使用复杂性。一个使得发射电流变化的重要因素就是场发射体对于不完全真空之中存在的剩余气体分子的吸附。这些吸附的分子改变了表面的逸出功，从而改变了发射电流密度。对于一个热发射体来说，这个吸附效应不如对于低温场发射体来说那么重要。这是因为热发射过程中使用的高温能从发射体表面脱附任何吸附物从而保持住表面逸出功不变。对于低温场发射体来说，因为没有除去这些吸附物的机制，后果就是发射电流的波动和随时间的衰减。为了减轻来自于吸附物的影响，一个直观的方法就是创造更好的真空来减少剩余气体。但是，对于更高真空的要求会增高仪器的费用并且牺牲操作的方便性。
目前商业使用的场发射体是具有高逸出功（ 4.5 电子伏）的钨（ W ）材料。当用于聚焦电子束仪器的时候，高逸出功制约了在一个可以接受的能量发散之下能达到的最高亮度。另外，我们知道钨（ W ）发射体会和真空里的主要是氢气的残余气体反应。它的衰减前平台期当真空不好于 1 × 10-10 托的时候通常短于 30 分钟；当真空不好于 1 × 10-12 托的时候短于 5 个小时。比较而言，在真空不好于 1 × 10-9 托的时候，肖特基发射体通常可以无衰减的发射电子。更短的平稳时期和更高的真空要求使得低温场发射体不像肖特基发射体那样受欢迎，尽管场发射体可以提供更高的亮度和更窄的能量发散。所以，特别需要设计出一个具有低逸出功和高表面惰性的可以在更差的真空环境里更长时间的稳定工作的低温场发射体材料。
普遍认为氧化物相对于它组成元素的金属来说化学惰性更大。但是，氧化物本身不能被用来做成低温场发射体，因为它们的导电性对于电子传输来说太低。一个低逸出功氧化物薄膜被覆在一个导电基板上的结构就可以足够好的传输电子来实现氧化物表面的低温场发射。为了造出一个稳定的结构，这个氧化物层必须很牢固的结合在导电基板上从而可以承受场发射过程中引出电压所产生的巨大静电力。氧化膜的震动或者剥落都会造成场发射电流的波动和衰减。通常，对于一种特定的基板材料，其只有一种或几种特定的晶面和一种特定的氧化物形成牢固的结合。所以，针状基板需要被做成一根沿着那个特定晶向的单晶，从而针尖的表面可以牢固的结合上一层氧化物薄膜。这样的结构同时具有汇聚束形状的优点，因为电子发射集中于那个特定的晶面，从而只有那个晶面具有低的逸出功。在往常的技术中，人们发现锆 Zr 的氧化物偏向性的结合在 W 的（ 100 ）表面，所以选择性的降低了 W （ 100 ）面的逸出功。当一根顶端是（ 100 ）晶面的尖的 W 针被用作基板并且镀上 ZrO 的时候，一个具有低逸出功（ 2.6 电子伏）的场发射体就做成了。（美国专利 3374386 ）一般认为， ZrO 在 W （ 100 ）表面形成稳定的薄膜的原因是基于 Zr 原子和 W （ 100 ）面晶格结构的晶格尺寸匹配。进一步的结果显示 W 的氧化物还能够在 W （ 110 ）面和（ 112 ）面之上形成薄膜。当针尖被加热到一个足以保证 W 原子高迁移率的温度的时候，这个薄膜帮助了 W 原子堆积到以（ 100 ）或（ 111 ）作为轴向的针尖顶上去。这种堆积针尖比原来没有堆积之前的 W 针尖更加的惰性。（美国专利 3817592, 7888654 B2 ）在这两种情况下， W 氧化物不是用来降低针尖顶面的表面逸出功。碱土氧化物，稀土氧化物，氧化钍，氧化铪都是稳定的化合物，而且比 ZrO 和 W 氧化物具有更低的逸出功。据所知的往常技术来看，没有一种基板材料和这些氧化物形成稳定的结合，以使我们可以基于这些氧化物做出一种既有更低的逸出功又有更高的表面惰性的场发射体。
关于制作一种具有凸起的顶点的针尖形貌，除了上文所述的堆积法以外，还有一个往常的技术（美国专利 7431856 B2 ）可以实现，那就是在施加一个电场的情况下，腐蚀气体会偏向于腐蚀针尖上面柱状的区域而不是顶点的区域，这种通过腐蚀来制作具有凸起顶点的针尖形貌的方法只跟针尖的形状有关，而与针尖材料的结晶性或者晶体取向无关 。
发明内容
本发明的目的之一是提供一种具有低逸出功和高化学稳定性的电极材料，包括能够导电的发射体和设置在所述发射体表面的电子发射层，其中，所述发射体由化合物基材制成，所述电子发射层的材质为氧化物薄膜。
所述化合物基材可以是板状、针状、柱状或块状等多种形状，该化合物基材具有可以和氧化物薄膜形成牢固结合的特定晶面。
根据本发明，所述化合物基材的材质选自金属硼化物、金属氮化物或金属碳化物，且其中的金属元素为钙、锶、钡、钪、钇、镧系元素、钍、钛、锆和铪中的一种或多种的组合。
优选地，所述金属硼化物可选自钙、锶、钡、钪、钇或镧系元素的单结晶六硼化物，且所述金属硼化物的结晶取向为晶格（ 100 ）、（ 110 ）或（ 111 ）方向。
优选地，所述金属碳化物可选自钍、钛、锆或铪的单结晶单碳化物，且所述金属碳化物的结晶取向为晶格（ 100 ）、（ 110 ）或（ 111 ）方向。
根据本发明，所述氧化物薄膜由金属氧化物构成，且所述氧化物薄膜中除氧元素以外的金属元素选自钙、锶、钡、钪、钇、镧系元素、钍、钛、锆和铪中的一种或多种的组合。
进一步地，所述化合物基材中的金属元素倾向于与所述氧化物薄膜中的金属元素组成相同，这样氧化物薄膜中除氧元素以外的组分元素可以直接由发射体自身提供，从而可省去另外的蒸发源或者蓄积源结构。
优选地，尤其当本发明电极材料用作电子束仪器的电子源时，发射体倾向于为针状，而氧化物薄膜层设置在该针状发射体的针尖位置。
进一步地，所述针状发射体的顶端形成垂直于所述针状发射体轴向的顶平台，所述氧化物薄膜层应至少覆盖住所述顶平台区域。该针状发射体的针尖应具有足够小的尺寸来产生场发射机制所需要的强电场，并且针尖的轴向应和一个特定的晶向平行，而垂直于这个晶向的晶面能够和氧化物薄膜形成牢固结合，此晶面就是顶平台所在晶面。
更进一步地，所述针状发射体的顶端形成轴向与所述发射体轴向平行或重合的顶圆柱，所述顶圆柱的顶面为垂直于所述发射体轴向的顶平台，所述氧化物薄膜至少覆盖住所述顶平台区域。顶圆柱的设置可以将高电场集中于顶平台，这种电场分布有利于将电子发射集中于顶平台区域，并减少顶平台周围邻近区域的物质向顶平台区的结构性堆积，因而能进一步提升电子发射的稳定性。
本发明的另一个目的是提供一种真空场致电子发射体，包括绝缘块、分别穿设于所述绝缘块上的两根金属柱、两端分别焊接在两根金属柱末端的一条灯丝，以及焊接在所述灯丝中部的针状基体；所述针状基体的顶部形成一个针尖，所述真空场致电子发射体还包括通过结合层设置在所述针状基体的针尖位置的柱形发射块，以及设置在所述柱形发射块顶部的电子发射层；所述柱形发射块具有柱面区，所述柱面区的顶边向着所述发射块的轴向向内收缩形成锥面区，所述锥面区的顶部形成垂直于所述发射块轴向的顶平台，所述电子发射层即设置在所述顶平台上；所述发射块由化合物基材制成，所述电子发射层的材质为氧化物薄膜。
优选地，所述发射块的材质选自金属硼化物、金属氮化物或金属碳化物，且其中的金属元素为钙、锶、钡、钪、钇、镧系元素、钍、钛、锆和铪中的一种或多种的组合。
优选地，所述氧化物薄膜由金属氧化物构成，所述氧化物薄膜中除氧元素以外的金属元素选自钙、锶、钡、钪、钇、镧系元素、钍、钛、锆和铪中的一种或多种的组合。
优选地，所述针状基体由高熔点导电材料制成，且所述高熔点导电材料选自碳、钨、铼、钽或钼。
优选地，所述结合层由碳、铂或钨元素构成。
优选地，所述发射块的锥面区上形成一个轴向与所述发射体轴向平行或重合的顶圆柱，所述顶圆柱的顶面为垂直于所述发射块轴向的顶平台。
本发明的第三个目的是提供一种在材质为金属六硼化物的针状或柱状发射体顶端制备顶圆柱的方法，包括如下步骤：
a 、真空下，使所述发射体的顶端形成一个半球形表面，该半球形表面的顶端为（ 100 ）晶面；
b 、在一定腐蚀气体的气压下，相对于所述发射体的一个邻近电极在所述发射体上施加正电压；
c 、当所述半球形表面随着腐蚀气体的腐蚀，顶端的（ 100 ）晶面的腐蚀速度慢于其它晶面的腐蚀速度，而使得所述半球形表面形成垂直于所述发射体轴向的圆柱形时，撤除所加正电压和腐蚀气体，所述顶圆柱即已形成。
优选地，上述方法中所述的腐蚀气体为氧气、氮气或者水汽。
本发明的第四个目的是提供另一种真空场致电子发射体，它包括绝缘块、分别穿设于所述绝缘块上的两根金属柱、分别与所述两根金属柱的末端相焊接的两根灯丝、焊接在所述两根灯丝之间的两块石墨加热板，以及夹设在所述两块石墨加热板中间的块状基体；所述块状基体的中央向上凸起形成具有尖端的针状发射体，所述针状发射体的尖端位置形成垂直于所述针状发射体轴向的顶平台，所述真空场致电子发射体还包括设置在所述针状发射体顶端的电子发射层；所述针状发射体由化合物基材制成，所述电子发射层的材质为氧化物薄膜。
优选地，所述块状基体和所述针状发射体的材质选自金属硼化物、金属氮化物或金属碳化物，且其中的金属元素为钙、锶、钡、钪、钇、镧系元素、钍、钛、锆和铪中的一种或多种的组合。
优选地，所述氧化物薄膜由金属氧化物构成，且所述氧化物薄膜中除氧元素以外的金属元素选自钙、锶、钡、钪、钇、镧系元素、钍、钛、锆和铪中的一种或多种的组合。
本发明的第五个目的是提供一种在针状或柱状发射体的顶平台上设置氧化物薄膜层的方法，包括如下步骤：
a 、在发射体的顶平台邻近表面设置氧化物；
b 、真空下，相对于顶平台的一个邻近电极在所述发射体上施加电压，使氧化物扩散到顶平台上；
c 、当顶平台被氧化物完全覆盖后，停止所加电压，所述氧化物薄膜层即已在发射体的顶平台上设置完成。
优选地，步骤 a 是通过在含氧气体中加热所述发射体来实现。
优选地，步骤 a 还可以通过利用薄膜沉积技术在顶平台的邻近表面沉积氧化物来实现。
优选地，步骤 b 中还伴随加热到一个使氧化物迁移率增加的温度，至步骤 b 完成停止加热。
优选地，上述方法在步骤 c 完成后还包括步骤 d ：把发射体加热到一个低于氧化物薄膜蒸发点的温度来实现氧化物薄膜层与顶平台的牢固结合。
优选地，步骤 d 还可以是如下的方法：在加热或不加热的情况下，使发射体在一段时间内保持在一定的含氧气体气压下以实现氧化物薄膜层与顶平台的牢固结合。
本发明的电极材料可用于能够提供电子的电子源，且该电极材料适于通过场发射形式来发射电子。
为增加上述电子材料发射电子的稳定性，该电极材料在运行时还伴随加热，但加热温度应低于能够使所述电极材料通过热发射形式发射电子的温度。
本发明的电极材料能够作为电子束仪器的真空电子源、有机或无机发光二极管的电子注射电极，以及有机或无机太阳能电池、有机或无机晶体管和电化学装置的阴极而应用。
所述的电子束仪器包括扫描电子显微镜、透射电子显微镜、扫描透射电子显微镜、电子束刻蚀机器、能量漫散 x 射线能谱仪、电子能量损失能谱仪等。
本发明与现有技术相比具有如下优点：
本发明的电极材料在发射电子时具有更低的逸出功，同时氧化物薄膜层与发射体结合更牢固，化学稳定性更高。本发明真空场致电子发射体可以实现长时间高电流密度且保持电流密度不变化的电子发射。
附图说明
下面结合附图和具体的实施方式对本发明做进一步详细的说明：
图 1 为实施例 1 的真空场致电子发射体的整体结构图；
图 2 为图 1 中针尖的放大图；
图 3 为图 2 的俯视图；
图 4 为图 2 中顶平台的放大图；
图 5 为实施例 2 的真空场致电子发射体的针尖放大图；
图 6 为实施例 3 的真空场致电子发射体的整体结构图；
图 7 为制作本发明真空场致电子发射体的流程图；
图 8 为本发明真空场致电子发射体中设置氧化物薄膜层的流程图；
图 9 为使用本发明真空场致电子发射体的电子束仪器结构图。
具体实施方式
本发明的氧化物薄膜层可以牢固的结合在金属硼化物、碳化物或者是氮化物的化合物基材之上，从而可以实现长时间的高电流密度的电子发射，且保持电流密度不变化。虽然为什么相对于往常方法中所使用的高温金属基材，本发明的化合物基材具有更好的和氧化物薄膜层的结合强度，其原因尚未完全清楚，但是起码部分原因是基于氧化物薄膜层和化合物基材的原子都是由共价键结合的事实，从而使得氧化物薄膜层与化合物基材具有更好的相容性。第二个可能的原因就是当氧化物薄膜层和化合物基材都由相同的金属元素组成时，氧化物薄膜层和化合物基材的晶格尺寸应该相似，从而减小了两者的界面匹配差。我们倾向于使氧化物薄膜层和化合物基材两者具有相同的金属组成的另一层原因是，在此种情况下，氧化物薄膜层可以直接由氧气和化合物基材反应来实现在化合物基材表面的附着，这就给电子枪的制造和运行带来了方便。
低逸出功的氧化物薄膜层所包含的金属组分通常都是低熔点高反应活性的。所以，用这些金属组分的单质形态来制作发射体基材，蒸发源或者扩散蓄积源都是非常困难的。而这些金属对应的硼化物、碳化物或者氮化物都是高熔点、高机械强度和低反应活性的，它们就可以直接用作一个合适的发射体基材。正因如此，我们就可以很简单地选择任何具有低逸出功的金属氧化物来作为发射体的电子发射层，而不受金属选择的限制。需要更进一步声明的是本发明的这种电极材料除了做成针状结构而作为真空电子发射源外，还可以有其他的应用，例如，本发明可以做成板状或块状而用作有机或无机发光二极管的电子注射电极，有机或无机太阳能电池，有机或无机晶体管以及电化学装置的阴极等。
以下的内容将给出对于本发明的具体描述和实例。需要向本领域中的专业人士指出的是，以下给出的实例可以直接用来改造出其他薄膜／化合物基材的组合结构，但是都应该被认定为不偏离本专利核心内容的自然延伸。
下面结合具体的实施例对本发明做进一步详细的说明，但不限于这些实施例。
实施例 1
如图 1 所示，本实施例的真空场致电子发射体 100 为一个基体针 104 焊接在灯丝 106 上。灯丝 106 的两端分别焊接在两个金属柱 108 上。该两个金属柱 108 由一个绝缘块 110 机械的联在一起并且提供电绝缘。基体针 104 具有一个小曲率半径的针尖 102 ，此曲率半径应小于 10 微米而大于 100 纳米。灯丝 106 是用来通过一定的电流从而以焦尔加热的方式加热基体针 104 。基体针 104 由高熔点导电材料做成。这些材料包括但不限于 C ， W ， Re ， Ta ，和 Mo 。基体针 104 的材料应该具有比此真空场致电子发射体的清洁温度和使用温度更高的熔点。在一个具体的实例中，清洁温度和运行温度预期高至 1300K 。基体针 104 既可以是单结晶又可以是多晶。其针尖 102 可以是任意晶体结构取向。
图 2 展示了基体针 104 的针尖 102 的放大视图，基体针 104 被截出一个平台，另外有两个部分被建造在这个平台之上：柱形发射块 200 和结合层 208 。发射块 200 要求具有至少以下三部分：一个顶平台 202 ，一个锥面区 204 以及一个柱面区 206 。至少顶平台 202 被氧化物薄膜层覆盖以用来发射电子。顶平台 202 的半径倾向于小于 500 纳米，更倾向于小于 100 纳米，最倾向于小于 10 纳米。在某些实例中，顶平台 202 由几个原子甚至或者是一个单一原子构成。柱面区 206 的半径应大于或等于顶平台 202 的半径。在基体针 104 的再生过程中，当原有的顶平台 202 和锥面区 204 需要被去处的情况下，柱面区 206 可以被用来形成一个新的顶平台和一个新的锥面区。但柱面区 206 的长度不应该超过一个临界值。超过这个值，振动变的严重，因而会影响发射图案的稳定性。本领域的专业人士应该容易的认识到这个临界长度值是随着发射块 200 的材料和半径的不同而变化的。图 3 为图 2 的俯视图用来帮助更好的看清发射块 200 的三个构成部分。
发射块 200 倾向于由导电的金属硼化物，碳化物，或者氮化物做成。其中的金属元素包括以下元素中的一种或多种的组合：包含 Ca ， Sr 和 Ba 的第二族元素；包含 Sc ， Y ，和镧系元素的第三族元素；包含 Zr ， Hf 和 Th 的第四族元素。例如，发射块 200 由 Ca ， Sr ， Ba ， Y ， La ， Ce 的六硼化物或者 Ti ， Zr ， Hf ， Ta ， Th 的单碳化物构成。发射块 200 倾向于为单结晶。此单结晶的轴向垂直于那个可以选择性结合所选氧化物薄膜层的晶面。在某些实例中，此单结晶方向倾向于为 <100> ， <110> 或 <111> 方向。针尖顶具有单个晶粒的多晶发射块自然也起到一样的作用。
结合层 208 应该导电并且它的半径应大于或等于发射块 200 的半径。结合层 208 所用材料应该为那些高至此种真空场致电子发射体的清洁和使用温度都既不和发射块 200 也不和基体针 104 反应的材料。当结合层 208 和所结合部分之间有缓慢反应的时候，结合层 208 的厚度应大于此种真空场致电子发射体整个使用寿命中所产生的损耗。在某些实例中，结合层 208 可以由 C ， W 或者 Pt 做成。结合层 208 可以用以下的一些方法形成：例如，区域选择沉积或者通过降解含有所需组分的糊剂的方法。伴随着引入前驱气体，当利用机械操纵器将发射块 200 和基体针 104 靠近的时候，电子束诱发沉积或者离子束诱发沉积可以用来沉积结合层 208 。环氧树脂液滴也可以用来连接发射块 200 和基体针 104 。环氧树脂液滴可以接下来通过真空热碳化来变为 C 结合层。
图 4 为发射块 200 的顶平台 202 的放大视图。氧化物薄膜层 402 被覆在顶平台 202 之上用来作为电子发射层。此氧化物薄膜层中除氧元素以外的元素含有以下元素中的一种或多种的组合：包含了 Ca ， Sr ， Ba 的第二族元素；或包含了 Sc ， Y 和镧系元素的第三族元素；或包含了 Zr ， Hf 和 Th 的第四族元素。氧化物薄膜层 402 倾向于同发射块 200 具有同样的金属组分，因为这样可以具有小界面匹配差而且可以直接通过让发射块 200 与氧气反应来生成这种氧化物薄膜。当尽管组分金属不同，但氧化物薄膜层 402 与底下的发射块 200 仍能形成小的界面匹配差，从而可以牢固的结合在发射块 200 之上的情况下，氧化物薄膜层 402 也可以和发射块 200 使用不同的组分金属。例如， La 和 Ce 具有相似的尺寸和化学性质。所以，很明显我们可以在 LaB6 上面附着 CeOx （ x 为未知）薄膜层或者在 CeB6 上面附着 LaOx （ x 为未知）薄膜层。同样，很明显我们可以在混合的化合物基板比如 LazCe （ 1 － z ） B6 上面附着混合的氧化物薄膜层比如 LaxCeyO 。只要混合组合能够提供好的界面结合，任何组合都是可以使用的。本领域专业人士应该可以认识到，即使氧化物薄膜层 402 和发射块 200 具有同样的金属元素，其界面的匹配差也许比当他们具有不同元素的情况还要大。例如，当硼化物作为发射块 200 的材料时， O 和 B 的尺寸不同所带来的额外的尺寸差别会造成这种情况。在这些情况下，当相对于氧化物薄膜层 402 的形成便捷来说，更需要最佳的结合强度的时候，氧化物薄膜层 402 中的金属元素也许更倾向于使用与发射块 200 所含金属元素不同的元素。发射块 200 的顶平台 202 倾向于完全被覆一层至少具有单分子层厚度的氧化物薄膜。氧化物薄膜层 402 的厚度不应超过一个临界值。那就是超过这个临界厚度之后，使得此种真空场致电子发射体的结构稳定性变差或者由于氧化物薄膜层 402 的电阻变大至影响电子发射性能。
实施例 2
本实施例提供了另一种与实施例 1 产品稍有不同的真空场致电子发射体，此种真空场致电子发射体与实施例 1 产品的区别在于发射块的结构不同。如图 5 所示，本实施例中的发射块 500 由至少 4 部分组成：顶平台 502 ，顶圆柱 504 ，锥面区 506 以及柱面区 508 。除了顶圆柱 504 以外，本实施例发射块 500 的其余部分应与实施例 1 中的针尖 102 具有相同的结构和功能。顶圆柱 504 是用来减小锥面区 506 的电场强度从而将高电场集中于顶平台 502 上。这样造成的电场分布有利于将电子发射集中于顶平台 502 并且减少锥面区 506 上的物质向顶平台 502 上进行结构性堆积。这样的结构进一步的提升了本实施例真空场致电子发射体的发射稳定性。本实施例带有顶圆柱的发射块结构可基于以下原则制造：化合物基材发射体中不同取向的晶面之间，腐蚀速度不一样。例如，当含有氧元素的气体作为腐蚀剂的时候，金属六硼化物结构的（ 100 ）晶面具有低于其他晶面的腐蚀速度。一个用来形成这种结构的具体方法包括以下步骤：首先，于一个真空容器中，在发射体针尖表面形成（ 100 ）晶面；然后，在发射体上相对于对面的一个邻近电极施加一个正电压并且同时将含氧气体引入此真空。当发射块的顶平台 502 为（ 100 ）晶面的时候，顶平台 502 将具有最慢的腐蚀率。周边不是（ 100 ）的晶面所遭受的更高的材料去除率将形成顶圆柱 504 。在金属六硼化物的针尖顶端表面制作出（ 100 ）晶面，可以选择诸如场协助氢气腐蚀、真空场蒸发以及热退火等技术。在第二个步骤中，更高的所加电压、更强的腐蚀剂类型、更高的腐蚀剂气体压力、更高的温度和更长的时间都能带来顶平台 502 周围区域的更快的材料去除。在一个关于第二步的实例中，使用以下参数制作了一个上述在顶圆柱 504 上的顶平台 502 ：所加电压在 2000V 到 8000V 之间，腐蚀气体压力在 1 × 10-8 托 ~1 × 10-5 托之间，腐蚀气体为氧气或者水，温度为室温。从以上可知，对于本领域的专业人士来说，只要用通常的技术，通过选择不同的电压、腐蚀剂种类、压力、温度和操作时间就可以形成上述的顶圆柱 504 。
实施例 3
本实施例提供了另一种真空场致电子发射体，它也具有绝缘块、设置在所述绝缘块上的两根金属柱和与两根金属柱焊接的灯丝。如图 6 所示，本实施例的真空场致电子发射体 600 还包括块状发射体 601 ，块状发射体 601 分为两个部分：凸起于块状发射体 601 上表面中部的发射尖 602 和基体 604 。两根灯丝 608 的端部分别和加热板 606 焊在一起，而块状发射体 601 即设置在两个加热板 606 中间。加热板 606 起到两个作用：一个是机械的支撑起块状发射体 601 ；另一个功能是当通过电流的时候产生热。加热板 606 倾向于由石墨做成。本实施例中，块状发射体 601 倾向于由导电的金属硼化物、金属碳化物或者金属氮化物做成，这些化合物的金属构成元素包括：包含了 Ca ， Sr ， Ba 的第二族元素；或包含了 Sc ， Y 和镧系元素的第三族元素；或包含了 Zr ， Hf 和 Th 的第四族元素；或这些元素的组合。例如，块状发射体 601 由 Ca ， Sr ， Ba ， Y ， La ， Ce 的六硼化物或者 Ti ， Zr ， Hf ， Ta ， Th 的单碳化物构成。块状发射体 601 倾向于为单晶，且晶体轴向垂直于那些需要选择性地和所选氧化物薄膜层结合的晶面。在一些实例中，晶体轴向倾向于为 <100> ， <110> 或 <111> 方向。具有一个发射尖单晶晶粒的多晶块状发射体也可以用来实现相同的目的。发射尖 602 的针尖顶结构倾向于和图 2 以及图 5 中所描述的遵循一样的原则。发射尖 602 可以用微观加工来制作。例如，一块单晶可以先被切成基体 604 的形状，然后，利用聚焦离子束（ FIB ）铣加工来去除基体 604 周围的材料直到一个发射尖 602 形成。
实施例 4
发射体的材质和形状，以及氧化物薄膜层的材质和尺寸不同，都会对所制得的场致电子发射体产品的使用造成影响。本实施例提供了多个本发明制备的真空场致电子发射体的运行实例，以说明本发明产品相对于现有技术能够实现在更高的气体压力下更长时间的稳定运行。
在一个例子中，本申请人测试了一个场致电子发射体产品：在小于 800v 的引出电压，小于 3 微安的发射电流，小于 1000K 的加热温度，小于 5 ％的电流波动和不好于 3 × 10-9 托的真空下，该场致电子发射体运行稳定时间超过 100 小时；
在另一个例子中，本申请人测试了一个场致电子发射体产品：在小于 500v 的引出电压，小于 1 微安的发射电流，小于 800K 的加热温度，小于 5 ％的电流波动和不好于 2 × 10-10 托的真空下，该场致电子发射体运行稳定时间超过 30 小时；
在另一个例子中，本申请人测试了一个场致电子发射体产品：在小于 1000v 的引出电压，小于 10 微安的发射电流，小于 1100K 的加热温度，小于 5 ％的电流波动和不好于 3 × 10-9 托的真空下，该场致电子发射体运行稳定时间超过 60 小时；
在另一个例子中，本申请人测试了一个场致电子发射体产品：在小于 700v 的引出电压，小于 5 微安的发射电流，小于 700K 的加热温度，小于 10 ％的电流波动和不好于 1 × 10-10 托的真空下，该场致电子发射体运行稳定时间超过 40 小时。
上面给出的运行参数应当理解为仅为例子，而并不是本发明的限制。
实施例 5
本实施例提供了一种用来制作本发明真空场致电子发射体的方法和流程。如图 7 所示，在步骤 704 中，一段基体线材被焊在一个灯丝结构的中部。此灯丝结构的两端分别和一个金属引脚柱焊在一起。引脚柱被镶嵌在一个绝缘块之中（可参见图 1 ）。在步骤 712 中，基体线材的顶部被侵入到一个腐蚀剂溶液中，并且相对于一个邻近的 Pt 圈被加上一个电压。腐蚀剂种类、浓度和所加电压的类型随着基体线材的种类不同而不同。基体线材经过电化学腐蚀过程被腐蚀成一个基体针。对于本领域技术人员来说，在该基体针上做成一个具有小于 10 微米曲率半径的针尖是很容易的事情。对于是否使基体针的针尖截成平台形式不是必须的，当然最好是使针尖处形成一个平台，以便于设置发射块。该平台可以用微加工技术来制作，例如聚焦离子束铣加工等。在步骤 716 中，基体的针尖被覆上一层保护层从而可避免针尖材料和接下来将要设置到该基体针尖上的发射块材料相反应。在一个例子中，上述保护层由 C 制成。多种技术可以用来给基体针覆上这种保护层，例如化学气相沉积、环氧树脂热降解或者带电粒子束诱发沉积等。一个平行步骤 708 用来制作发射块。一个具体制作发射块的方法包括如下步骤：拿来一块所需发射块材料的单晶体；若此单晶体不满足所需的三维尺寸，则用聚焦离子束铣加工技术将此单晶加工成具有宽、厚、高三个所需维度的块体或柱体。该块体或柱体的所需宽度和厚度均在 10 纳米 ~10 微米之间，所需高度则在 500 纳米 ~50 微米之间。在步骤 720 中，将制备好的具有所需尺寸的发射块隔着保护层放置在基体针尖邻近，使发射块的高和基体针的轴向平行或对齐重合。可以使用例如电驱动的机械操作仪来实现精确的对齐。接下来在发射块和基体针尖的接合处覆上结合层来机械的固定住这个结构并且提供电传导。当结合层足够厚并且发射块不是直接和基体针材料相接触的情况下，步骤 716 中所述保护层可以省略。在步骤 724 中，发射块的顶部被加工成一个具有小曲率半径的针尖，优选地，该针尖的曲率半径在 5 纳米 ~200 纳米之间。如果直接从步骤 708 中所制作出的发射块不符合此尺寸要求，可使用聚焦离子束铣加工来减小针尖曲率半径到所需尺寸。在步骤 728 中，如图 2 和图 5 中所示，将发射块顶部做一个顶平台，该平台的面积倾向于小于 400 平方纳米。可以用来制作这个平台的技术包括：聚焦离子束铣加工，场协助氢气，氮气或者氧气腐蚀，真空或者堕性气体场蒸发以及热退火等。发射块倾向于与那些密堆积原子面垂直的晶向平齐，这些晶向包括 <100>, <110> 和 <111> 方向。场腐蚀、场蒸发或者热退火所造成的表面小平面化都会形成密堆积面，而这些密堆积面就可以用作针尖顶部的平台。步骤 732 中，在发射块顶平台上形成氧化物薄膜层作为电子发射层。可以通过多种技术来形成这种氧化物薄膜层。在一个以 MOx 为例的实例中，其中 M 表示所需金属元素， x 表示一个未知的化学计量，通过加热一个含有 M 的源材料到蒸发温度，此蒸发源被用来提供含有 M 元素的蒸气，氧可以被包括进源材料，也可以被作为另外的氧而引入。同时，既可以在 M 蒸气沉积的时候引入氧从而形成 MOx ，也可以通过一个后续的氧化过程将 M 沉积层转化为 MOx 层。将 MOx 从此真空场致电子发射体以外的部分通过表面扩散到针尖平台的方法也可以用来形成这种氧化物薄膜层。对这种方法的具体描述在图 8 的框图中展示。
实施例 6
如图 8 所示，本实施例提供了一种用来在发射块的顶平台上形成氧化物薄膜层、并且在带电粒子仪器中使用的实例。在步骤 804 中，制作一个具有如图 2 或者图 5 所描述的发射块的场致电子发射体并且在发射块的尖端上制作一个顶平台。本实施例中的发射块倾向于为 MB6 材质，即金属元素 M 的六硼化物。金属元素 M 倾向于为 Ca ， Sr ， Ba ， Y ， La ，或者 Ce 。 MB6 发射块取向为晶体 <100> 方向。这样，顶平台就是该六硼化物 MB6 的（ 100 ）晶面。在步骤 808 中，将该场致电子发射体安装进一个带电粒子仪器作为电子发射源，然后对该仪器腔体进行真空排气。本发明中的的场致电子发射体所对应运行的真空环境中真空度均应好于 1 × 10-7 托。在步骤 812 中，发射块被加热到一个清洁温度，此清洁温度应当足够高到可以脱附掉该场致电子发射体表面吸附的可蒸发物质，这些可蒸发物质基本上为水和有机分子。在一个实例中，此清洁温度不超过 1000K 。应当知晓的是，清洁温度不应该超过会让组分金属的氧化物开始蒸发的温度。在一个实例中，清洁温度不超过 1300K ，或更倾向于不超过 1200K 。因为不同的所需金属元素的氧化物具有不同的蒸发点，很明显当使用不同的发射块材料时，清洁温度将有不同的上限。且加热清洁时间也会改变，这取决于场发射体上的吸附物数量以及所用的清洁温度。在一个实例中，所用清洁时间不超过 1 分钟。在步骤 816 中，检测所需的氧化物薄膜层是否在发射块的顶平台上形成，氧化物薄膜层形成的一个结果就是顶平台逸出功的降低。所以，任何可以用来测定逸出功数值或者逸出功变化的手段都可以用来实施这个检测。例如，可以记录下发射电流随着不同引出电压的变化来形成一个 I-V 曲线。从 I-V 曲线中，可以做出所谓的 fowler － nordheim 标绘。之后，此标绘的斜率可以用来测定发射体的逸出功。在一个实例中，可以在氧化物被覆处理之前测定逸出功，并且用来比较那些在经过特定被覆处理之后得到的逸出功数值。另一个测定的方法利用的现象就是：场发射电流随着发射体逸出功的降低会急剧的升高。在这个方法中，可以在任何被覆处理之前纪录一个固定的引出电压所对应的发射电流。在特定的处理之后，可以再次测定相同引出电压所对应的发射电流。当我们在实施了一个特定的被覆处理之后，可以重复的获得一个相对稳定的发射电流值并且那个值高过未经被覆处理的电流值的时候，我们就可以得出结论：氧化物层已经形成。另一个方法基于的现象就是：氧化物薄膜层在发射体顶部平台选择性的被覆将仅仅在顶平台上造成逸出功的降低，从而造成一个具有小于 30 度发散角的汇聚型的场发射图案。可以利用譬如荧光屏的成像装置纪录下场发射图案。当我们可以重复性的得到较为稳定的小发散角的场发射图案的时候，我们可以得出结论：氧化物薄膜层已经形成。如果氧化物薄膜层没有在顶平台上被覆形成，我们转去步骤 820 。在步骤 820 中，将含有氧的气体引入 MB6. 发射块附近从而在发射块的表面形成 MOx （ x 未知）氧化物。既可以在氧暴露之后，也可以在氧暴露之时把发射块加热到一个反应温度，从而确保 M 和 O 之间的反应。反应温度应低于在该含氧气体的所用压力下氧化物 MOx （ x 未知）的蒸发点。反应时间应足够让氧化物 MOx 生成。普遍来说，更高的氧暴露压力需要更低的反应温度以及更短的反应时间。在一个实例中，使用的氧气压力为 1 × 10-7 托到 1 个大气压之间，反应温度为 600K 到 1400K 之间，反应时间为 10 秒到 5 分钟之间。本领域的技术人员应很容易认识到，别的关于含氧气体种类、气压、反应温度和反应时间的组合都应被认作在本发明的范围之内。在某些情况下，氧化物已经在发射块安装进真空腔体之前，在制备或者处理过程中已经在发射块表面形成了。在这些情况下，步骤 820 变为可选环节而不是必须环节。在步骤 824 中，一个使氧化物扩散的过程被执行来选择性的在顶平台上形成氧化物薄膜层。我们发现，在电场存在下，发射块的表面氧化物可以扩散到 MB6 的（ 100 ）面上，在本实施例中，这个面也就是顶平台所在面。在一个优选的实例中，加到发射块上的电压相对于一个邻近电极是负偏压，并且它能够对应产生强度为 10 纳安 ~10 微安之间的发射电流。同时我们发现，伴随加电压，将发射体加热到一个适当的温度，可以帮助这个扩散过程从而使（ 100 ）面完全被覆氧化物所需要的时间能够更短。在一个优选的实例中，这个伴随加热的温度在 600K~1000K 之间。另一个发现就是：氧化物在电场下开始扩散之后，无论是加热或者不加热，都可以通过将发射体暴露在含氧气体中进行无电压的老化处理来实现氧化物在（ 100 ）面上的完全被覆。在一个例子中，此氧气压力在 1 × 10-8 托和 1 × 10-9 托之间，老化时间在 20 小时 ~60 小时之间。在经过上述氧化物被覆的处理过程之后，应再转到步骤 816 去检测氧化物薄膜层是否已完全形成。步骤 816 ，步骤 820 和步骤 824 应被循环使用直到确认氧化物薄膜层已完全形成。在某些情况下，比如当荧光屏被用来观测场发射图案的时候，步骤 816 可以和步骤 824 同时实施。如果氧化物薄膜层确认已形成，则转到下一步骤 828 。在步骤 828 中，加引出电压到该场致电子发射体上，从而产生一个想要的场发射电流。该场致电子发射体倾向于在不超过 400K 的温度下运行，因为低温运行可以带来最窄的能量发散。更高的运行温度则可以让本发明的场致电子发射体能够更长时间的稳定运行在更高的剩余气体压力下。运行温度不应该超过当前剩余气体压力下氧化物薄膜层 MOx （ x 未知）的蒸发点。在一个实例中，不应超过 1300K 。在步骤 832 中，检查该场致电子发射体的发射波动度。当场发射电流被电流表监视的时候，这个操作可以和步骤 828 同时进行。在运行之中，污染物或者多余的氧化物质会在氧化物薄膜层表面形成，从而造成发射电流波动。在这里，发射电流波动定义为在一分钟的时间内，发射电流的变化比上发射电流的平均值。在一个实例中， 10 ％作为发射波动临界值。当发射电流波动超过这个临界值的时候，应转向步骤 812 ，对该场致电子发射体加热使达到一个清洁温度从而恢复稳定的发射特性。通过在步骤 812 和步骤 832 之间的循环，能够实现可被电子束仪器实际应用的稳定电子发射。
实施例 7
本实施例提供了将本发明真空场致电子发射体安装在一个带电粒子仪器中的应用实例。如图 9 所示，本实施例中的电子束仪器是一个场发射扫描电子显微镜（ SEM ） 900 。本实施例的场致电子发射体 100 选用图 1 中所示的场致电子发射体，将该发射体安装在 SEM 的真空腔体 924 中，该发射体的两个灯丝电流引脚柱连接到腔体 924 的外部。一个灯丝电源 904 用来提供灯丝所用的加热电流。一个引出电极 916 放在该场致电子发射体 100 的尖端邻近用来使发射块能够释放出电子。引出电极 916 通过真空导入端子和腔体 924 的外界相连。一个引出电压电源 908 被用来维持该场致电子发射体 100 和引出电极 916 之间的引出电压差。通过施加引出电压，从该发射体 100 上产生出了电子束 912 。一个扫描和聚焦系统 920 用来将此电子束 912 聚焦成一个小的电子探针并且在样品 936 表面用此探针扫描。样品 936 是装在一个用来帮助观察样品的移动台 932 上的。一个信号探测器 928 装设在样品 936 邻近用来采集由电子探针和样品之间相互作用所产生的信号。一个真空泵 944 被用来生成腔体 924 内所需的真空。一个氧气源 940 用来引入腔体 924 内所需压力的含氧气体。含氧气体同样也可以通过降低真空泵 944 的抽气力来由周围环境提供，或者通过向腔体 924 外部泄漏而引入。因此，在这个实例中，氧气源 940 是可选的，而不是必须的。
以上对本发明做了详尽的描述，其目的在于让熟悉此领域技术的人士能够了解本发明的内容并加以实施，并不能以此限制本发明的保护范围，凡根据本发明的精神实质所作的等效变化或修饰，都应涵盖在本发明的保护范围内。

Claims (30)

1. 一种具有低逸出功和高化学稳定性的电极材料，其特征在于：所述电极材料包括能够导电的发射体和设置在所述发射体表面的电子发射层，其中，所述发射体由化合物基材制成，所述电子发射层的材质为氧化物薄膜。
2. 根据权利要求 1 所述的电极材料，其中，化合物基材的材质为金属硼化物或金属氮化物或金属碳化物，且其中的金属元素为钙、锶、钡、钪、钇、镧系元素、钍、钛、锆和铪中的一种或多种的组合。
3. 根据权利要求 2 所述的电极材料，其中，金属硼化物选自钙、锶、钡、钪、钇或镧系元素的单结晶六硼化物，且所述金属硼化物的结晶取向为晶格（ 100 ）、（ 110 ）或（ 111 ）方向。
4. 根据权利要求 2 所述的电极材料，其中，金属碳化物选自钍、钛、锆或铪的单结晶单碳化物，且所述金属碳化物的结晶取向为晶格（ 100 ）、（ 110 ）或（ 111 ）方向。
5. 根据权利要求 1 所述的电极材料，其中，氧化物薄膜由金属氧化物构成，且所述氧化物薄膜中除氧元素以外的金属元素选自钙、锶、钡、钪、钇、镧系元素、钍、钛、锆和铪中的一种或多种的组合。
6. 根据权利要求 1 所述的电极材料，其中，化合物基材选自金属硼化物、金属氮化物或金属碳化物，氧化物薄膜由金属氧化物构成，且化合物基材中的金属元素与氧化物薄膜中的金属元素组成相同。
7. 根据权利要求 1-6 中任一项所述的电极材料，其中，发射体呈针状，氧化物薄膜设置在针状的发射体的针尖位置。
8. 根据权利要求 7 所述的电极材料，其中，针状的发射体的顶端形成垂直于发射体轴向的顶平台，氧化物薄膜至少覆盖住顶平台区域。
9. 根据权利要求 8 所述的电极材料，其中，针状发射体的顶端形成轴向与发射体轴向平行或重合的顶圆柱，顶圆柱的顶面为垂直于发射体轴向的顶平台。
10. 一种真空场致电子发射体，包括绝缘块、分别穿设于所述绝缘块上的两根金属柱，其特征在于：所述真空场致电子发射体还包括
一灯丝，其两端分别焊接在所述两根金属柱末端；
针状基体，该针状基体焊接在所述灯丝中部，所述针状基体的顶部形成一针尖；
柱形发射块，该柱形发射块通过一结合层设置在所述针状基体的针尖位置，所述柱形发射块具有柱面区，所述柱面区的顶边朝着发射块的轴线向内收缩形成锥面区，所述锥面区的顶部形成垂直于发射块轴向的顶平台，发射块由化合物基材制成，所述电子发射层的材质为氧化物薄膜；
电子发射层，所述电子发射层设置在柱形发射块顶部的顶平台上。
11. 根据权利要求 10 所述的真空场致电子发射体，其中，发射块的材质选自金属硼化物、金属氮化物或金属碳化物，且其中的金属元素为钙、锶、钡、钪、钇、镧系元素、钍、钛、锆和铪中的一种或多种的组合。
12. 根据权利要求 10 所述的真空场致电子发射体，其中，氧化物薄膜由金属氧化物构成，且氧化物薄膜中的金属元素选自钙、锶、钡、钪、钇、镧系元素、钍、钛、锆和铪中的一种或多种的组合。
13. 根据权利要求 10 所述的真空场致电子发射体，其中，针状基体由高熔点导电材料制成，所述高熔点导电材料选自碳、钨、铼、钽或钼。
14. 根据权利要求 10 所述的真空场致电子发射体，其中，结合层由碳、铂或钨元素构成。
15. 根据权利要求 10 所述的真空场致电子发射体，其中，发射块的锥面区上形成一轴向与发射体轴向平行或重合的顶圆柱，所述顶圆柱的顶面为垂直于发射块轴向的顶平台。
16. 一种电极材料的制备方法，其特征在于：所述电极材料包括能够导电的发射体和设置在所述发射体表面的电子发射层，其中，所述发射体由化合物基材制成，所述电子发射层的材质为氧化物薄膜；
当所述化合物基材为金属六硼化物，所述发射体的结构为针状或柱状，且所述发射体的顶端形成轴向与所述发射体轴向平行或重合的顶圆柱时，所述电极材料的制备方法包括制备所述顶圆柱的步骤，且制备顶圆柱的具体过程如下：
a 、真空下，使发射体的顶端形成一半球形表面，该半球形表面的顶端为（ 100 ）晶面；
b 、在一定腐蚀气体的气压下，相对于发射体的一个邻近电极在发射体上施加正电压；
c 、当半球形表面随着腐蚀气体的腐蚀，顶端的（ 100 ）晶面的腐蚀速度慢于其它晶面的腐蚀速度，而使得所述半球形表面形成垂直于发射体轴向的圆柱形时，撤除所加正电压和腐蚀气体，所述顶圆柱即已形成。
17. 根据权利要求 16 所述的制备方法，其中，腐蚀气体为氧气、氮气或者水汽。
18. 一种真空场致电子发射体，包括绝缘块、分别穿设于所述绝缘块上的两根金属柱，其特征在于：所述真空场致电子发射体还包括分别与所述两根金属柱的末端相焊接的两根灯丝、焊接在所述两根灯丝之间的两块石墨加热板，以及夹设在所述两块石墨加热板中间的块状基体；所述块状基体的中央向上凸起形成具有尖端的针状发射体，所述针状发射体的尖端位置形成垂直于所述针状发射体轴向的顶平台，所述真空场致电子发射体还包括设置在所述针状发射体顶端的电子发射层；所述针状发射体由化合物基材制成，所述电子发射层的材质为氧化物薄膜。
19. 根据权利要求 18 所述的真空场致电子发射体，其中，块状基体和针状发射体的材质选自金属硼化物、金属氮化物或金属碳化物，且其中的金属元素为钙、锶、钡、钪、钇、镧系元素、钍、钛、锆和铪中的一种或多种的组合。
20. 根据权利要求 18 所述的真空场致电子发射体，其中，氧化物薄膜由金属氧化物构成，氧化物薄膜中的金属元素选自钙、锶、钡、钪、钇、镧系元素、钍、钛、锆和铪中的一种或多种的组合。
21. 一种电极材料的制备方法，其特征在于：所述电极材料包括能够导电的发射体和设置在所述发射体表面的电子发射层，其中，所述发射体由化合物基材制成，所述电子发射层的材质为氧化物薄膜；
当所述化合物基材为金属硼化物、金属氮化物或金属碳化物，所述发射体为针状或柱状，且发射体的顶端形成垂直于发射体轴向的顶平台时，所述电极材料的制备方法包括在发射体的顶平台上设置氧化物薄膜层的步骤，该步骤的过程如下：
a 、在发射体的顶平台邻近表面设置氧化物；
b 、真空下，相对于顶平台的一个邻近电极在所述发射体上施加电压，使氧化物扩散到所述顶平台上；
c 、当顶平台被氧化物完全覆盖后，停止所加电压，所述氧化物薄膜层即已在发射体的顶平台上设置完成。
22. 根据权利要求 21 所述的制备方法，其中，步骤 a 通过在含氧气体中加热发射体来实现。
23. 根据权利要求 21 所述的制备方法，其中，步骤 a 是通过利用薄膜沉积技术在顶平台的邻近表面沉积氧化物来实现。
24. 根据权利要求 21 所述的制备方法，其中，步骤 b 中还伴随加热到一使氧化物迁移率增加的温度，至步骤 b 完成而停止加热。
25. 根据权利要求 21 所述的制备方法，其中，该方法在步骤 c 完成后还包括步骤 d ：把发射体加热到一低于氧化物薄膜蒸发点的温度来实现氧化物薄膜层与顶平台的牢固结合。
26. 根据权利要求 21 所述的制备方法，其中，该方法在步骤 c 完成后还包括步骤 d ：在加热或不加热的情况下，使发射体在一段时间内保持在一定的含氧气体气压下以实现氧化物薄膜层与顶平台的牢固结合。
27. 权利要求 1-6 中任一项所述的电极材料作为能够提供电子的电子源的用途，所述电极材料运行时通过场发射形式而发射电子。
28. 权利要求 27 所述的电极材料的用途，其中，电极材料运行时伴随加热，且加热温度低于能够使所述电极材料通过热发射形式发射电子的温度。
29. 权利要求 1-6 中任一项所述的电极材料作为电子束仪器的真空电子源、有机或无机发光二极管的电子注射电极，以及有机或无机太阳能电池、有机或无机晶体管和电化学装置的阴极的用途。
30. 权利要求 29 中所述的电子束仪器包括扫描电子显微镜、透射电子显微镜、扫描透射电子显微镜、电子束刻蚀机器、能量漫散 x 射线能谱仪、电子能量损失能谱仪。
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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US10083812B1 (en) * 2015-12-04 2018-09-25 Applied Physics Technologies, Inc. Thermionic-enhanced field emission electron source composed of transition metal carbide material with sharp emitter end-form
WO2020206445A1 (en) * 2019-04-05 2020-10-08 Modern Electron, Inc Thermionic energy converter with thermal concentrating hot shell

Families Citing this family (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102629538B (zh) 2012-04-13 2014-03-19 吴江炀晟阴极材料有限公司 具有低逸出功和高化学稳定性的电极材料
JP6459135B2 (ja) * 2015-03-02 2019-01-30 国立研究開発法人物質・材料研究機構 エミッタの製造方法
JP2016207319A (ja) * 2015-04-17 2016-12-08 株式会社日立ハイテクノロジーズ 電界放出型電子源及びその製造方法
CN104880579B (zh) * 2015-06-02 2019-02-12 苏州明志金科仪器有限公司 超高真空自旋极化扫描隧道显微镜探针的制备方法和装置
JP6529920B2 (ja) * 2016-03-01 2019-06-12 株式会社日立ハイテクノロジーズ 電界放出電子源、その製造方法および電子線装置
US10545258B2 (en) * 2016-03-24 2020-01-28 Schlumberger Technology Corporation Charged particle emitter assembly for radiation generator
US9984846B2 (en) * 2016-06-30 2018-05-29 Kla-Tencor Corporation High brightness boron-containing electron beam emitters for use in a vacuum environment
CN109791862A (zh) 2016-08-08 2019-05-21 Asml荷兰有限公司 电子发射器及其制造方法
US20190198284A1 (en) * 2016-09-06 2019-06-27 Hitachi High-Technologies Corporation Electron source and electron beam irradiation device
CN109804450B (zh) 2016-10-13 2020-12-01 株式会社日立高新技术 电子束装置
CN106783460A (zh) * 2017-01-05 2017-05-31 武汉科技大学 一种低逸出功阴极
WO2019107113A1 (ja) * 2017-11-29 2019-06-06 国立研究開発法人物質・材料研究機構 エミッタ、それを用いた電子銃、それを用いた電子機器、および、その製造方法
CN111048383B (zh) * 2018-10-12 2021-01-15 中国电子科技集团公司第三十八研究所 电子源和电子枪
CN111048373B (zh) 2018-10-12 2021-04-27 中国电子科技集团公司第三十八研究所 一种电子源再生方法
CN111048382B (zh) * 2018-10-12 2021-03-23 中国电子科技集团公司第三十八研究所 电子源制造方法
CN111048372B (zh) * 2018-10-12 2021-04-27 中国电子科技集团公司第三十八研究所 一种电子源工作方法
GB2583359A (en) * 2019-04-25 2020-10-28 Aquasium Tech Limited Electron beam emitting assembly
US11948769B2 (en) 2022-01-12 2024-04-02 Applied Physics Technologies, Inc. Monolithic heater for thermionic electron cathode

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3374386A (en) 1964-11-02 1968-03-19 Field Emission Corp Field emission cathode having tungsten miller indices 100 plane coated with zirconium, hafnium or magnesium on oxygen binder
US3817592A (en) 1972-09-29 1974-06-18 Linfield Res Inst Method for reproducibly fabricating and using stable thermal-field emission cathodes
US20030127593A1 (en) * 2002-01-09 2003-07-10 Hitachi High-Technologies Corporation Apparatus and method for wafer pattern inspection
US6680562B1 (en) * 1999-08-20 2004-01-20 Fei Company Schottky emitter having extended life
US7431856B2 (en) 2005-05-18 2008-10-07 National Research Council Of Canada Nano-tip fabrication by spatially controlled etching
US7888654B2 (en) 2007-01-24 2011-02-15 Fei Company Cold field emitter
CN102629538A (zh) * 2012-04-13 2012-08-08 吴江炀晟阴极材料有限公司 具有低逸出功和高化学稳定性的电极材料

Family Cites Families (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1210007A (en) * 1968-07-05 1970-10-28 Mullard Ltd Cathode
JPS5617780B2 (zh) * 1973-03-26 1981-04-24
JPS53114660A (en) * 1977-03-16 1978-10-06 Jeol Ltd Cathode for thermal electron emission
US4137476A (en) * 1977-05-18 1979-01-30 Denki Kagaku Kogyo Kabushiki Kaisha Thermionic cathode
JPS5588233A (en) * 1978-12-26 1980-07-03 Denki Kagaku Kogyo Kk Hexaboride single crystal cathode
JPS57128436A (en) * 1981-02-02 1982-08-10 Koichi Kanetani Manufacture of lanthanum-boride thermionic emission electrode
US4468586A (en) * 1981-05-26 1984-08-28 International Business Machines Corporation Shaped electron emission from single crystal lanthanum hexaboride with intensity distribution
JPS5971232A (ja) * 1982-10-14 1984-04-21 Natl Inst For Res In Inorg Mater 表面酸化型炭化物フィールドエミッターの製造法
US6190579B1 (en) * 1997-09-08 2001-02-20 Integrated Thermal Sciences, Inc. Electron emission materials and components
JP2000021290A (ja) * 1998-07-03 2000-01-21 Canon Inc 電子放出素子、電子源、画像形成装置及びそれらの製造方法
US6387717B1 (en) * 2000-04-26 2002-05-14 Micron Technology, Inc. Field emission tips and methods for fabricating the same
CN100372047C (zh) * 2005-09-09 2008-02-27 清华大学 一种薄膜场发射显示器件及其场发射阴极的制备方法
JP2009146705A (ja) * 2007-12-13 2009-07-02 Sumitomo Electric Ind Ltd 電子放出素子、電子源、電子線装置、及び電子放出素子の製造方法
CN102394204B (zh) * 2008-03-19 2014-10-08 清华大学 场发射电子源
JP2010157490A (ja) * 2008-12-02 2010-07-15 Canon Inc 電子放出素子および該電子放出素子を用いた表示パネル
JP5660564B2 (ja) * 2009-04-20 2015-01-28 独立行政法人物質・材料研究機構 希土類六ホウ化物冷陰極電界放出型電子源

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3374386A (en) 1964-11-02 1968-03-19 Field Emission Corp Field emission cathode having tungsten miller indices 100 plane coated with zirconium, hafnium or magnesium on oxygen binder
US3817592A (en) 1972-09-29 1974-06-18 Linfield Res Inst Method for reproducibly fabricating and using stable thermal-field emission cathodes
US6680562B1 (en) * 1999-08-20 2004-01-20 Fei Company Schottky emitter having extended life
US20030127593A1 (en) * 2002-01-09 2003-07-10 Hitachi High-Technologies Corporation Apparatus and method for wafer pattern inspection
US7431856B2 (en) 2005-05-18 2008-10-07 National Research Council Of Canada Nano-tip fabrication by spatially controlled etching
US7888654B2 (en) 2007-01-24 2011-02-15 Fei Company Cold field emitter
CN102629538A (zh) * 2012-04-13 2012-08-08 吴江炀晟阴极材料有限公司 具有低逸出功和高化学稳定性的电极材料

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US10083812B1 (en) * 2015-12-04 2018-09-25 Applied Physics Technologies, Inc. Thermionic-enhanced field emission electron source composed of transition metal carbide material with sharp emitter end-form
WO2020206445A1 (en) * 2019-04-05 2020-10-08 Modern Electron, Inc Thermionic energy converter with thermal concentrating hot shell
US11626273B2 (en) 2019-04-05 2023-04-11 Modern Electron, Inc. Thermionic energy converter with thermal concentrating hot shell

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