Electron emission device and electronic device

Abstract

The invention discloses an electron emission device and an electronic device, the electron emission device comprises a fire-resistant container and a heating power supply, the fire-resistant container is provided with a cavity part, the cavity part has a certain vacuum degree, an electron emission material is arranged in the cavity part, at least one through hole is formed in the bottom of the fire-resistant container, and the through hole is communicated with the cavity part. The electron emission material passes through the through hole to form an arc-shaped convex liquid surface after being heated and melted, and electron emission is realized outwards. According to the embodiment of the invention, the electronic field emission effect is relatively high, the product structure consistency degree is high, the debugging is easy, and the service life of the electronic emission device is in direct proportion to the mass of the contained electronic emission material, so that the service life of the disclosed electronic device can be remarkably prolonged compared with the service life of a traditional thermal field emission and cold field emission filament; and the application requirements of electron beam exposure machines, scanning electron microscopes, transmission electron microscopes and other X light sources can be met.

Description

Technical Field

[0001] The present disclosure relates to an electron emission source, and more particularly to an electron emission device. Background Art

[0002] The electron emission device is an important invention in modern times. Its applications in people's daily life include cathode ray tube displays and ray tubes that use the electron beam generated by it to accelerate to a high voltage and then bombard heavy metals to produce x-rays. Although cathode ray tube displays have now faded out of our daily lives, the X-ray source excited by the electron emission device is still widely used in medical equipment such as chest X-rays and CT for examinations. The vacuum electron tube prepared by the electron emission device also has a very important position in high-frequency and high-power microwave technology, such as radar. In scientific research, scanning electron microscopes, transmission electron microscopes, mass spectrometers, etc. are inseparable from electron emission devices. The electron beam exposure machine, which is the manufacturing equipment for photolithography masks in modern chip production technology, is also inseparable from electron generating devices.

[0003] The main physical mechanisms of existing electron generation devices include light excitation, thermal excitation, electric field excitation and secondary electron generation or their combined use. Among them, light excitation electron generation technology is mainly used for photomultiplier tubes; scanning electron microscopes and electron beam exposure technologies mainly use thermal excitation and electric field excitation technologies, especially thermal field emission and cold field emission technologies. Thermal field emission technology is widely used in electron beam exposure machines and high-end scanning electron microscopes and transmission electron microscopes because it can output very stable and high electron beam currents for a long time. The current thermal field emission electron beam device is a thermal field electron emission filament. When electrons are emitted, the filament material is solid, and the strong electric field required for field emission depends on the processing accuracy of the filament tip. Usually, chemical etching of tungsten single crystals is used to form a needle tip with a very large aspect ratio. The tip radius is within 100nm to ensure the strong electric field required for field emission. Its disadvantages are:

[0004] 1) The geometry and size repeatability of the needle tip processed by chemically corroded tungsten single crystal are poor, the consistency of the processed filament electron emission is not high, and the installation and debugging are troublesome;

[0005] 2) The filament has large geometric dimensions. Usually, the diameter of the filament for electron microscope is 1-2 cm after assembly. Such filaments are difficult to be made into arrays and installed in electron microscopes or electron beam lithography machines.

[0006] 3) The life of the filament is relatively short, generally around 10,000 hours;

[0007] 4) Defects and adsorption in the tungsten needle tip after chemical corrosion may cause the filament to emit unstable electron beam or fail;

[0008] 5) The current needle tip preparation process is limited to a few materials such as W and LaB6, which limits the range of materials for electron beam emission devices. Summary of the invention

[0009] In view of this, the embodiments of the present disclosure propose an electron emission device and an electronic device to solve the shortcomings of existing solid thermal emission or thermal field emission filament products, such as insufficient consistency, difficulty in preparing the filament into a compact array, and short life.

[0010] The present disclosure provides an electron emission device, which includes: a refractory container, a heating power supply and an extraction power supply; the refractory container has a cavity portion, and the cavity portion has a certain vacuum degree; the cavity portion is a circular cavity, and its inner diameter is in the range of 1um to 100um; the heating power supply is connected to the outer wall of the refractory container, and the heating power supply heats the electron emission material in the refractory container to its melting temperature or above by adjusting the power; the refractory container is made of conductive material; the heating power supply is a constant voltage DC power supply, and its output The current is between 0A and 10A; an electron emission material is arranged in the cavity, and at least one through hole is arranged at the bottom of the refractory container. After the electron emission material is heated and melted, it passes through the through hole to form an arc-shaped convex liquid surface and realizes electron emission outward; the convex liquid surface is further stretched out into a droplet structure with a smaller radius under the action of a high electric field to form a liquid needle tip structure, thereby further enhancing the local electric field and generating a field emission effect of electrons; a corresponding annular lead-out electrode is arranged below each of the through holes, and the lead-out electrode is arranged opposite to the convex liquid surface. ; The spacing between the through hole and the extraction electrode is 50um to 5000um; The inner diameter of the annular extraction electrode is 1um to 100um; A plurality of through holes are arranged at the bottom of the refractory container to form an electron emission array; The through holes are micron-level through holes formed by micro-nano processing technology, and the diameter of the through holes is between 0.1um and 100um; There is no chemical reaction between the electron emission material and the material of the refractory container, and no alloy is formed; The electron emission material is at least one of a semiconductor material, an electrical insulating material, and a metal material ; The semiconductor material is GaAs or InP; or the electrical insulating material is at least one of CsO2, Zr2O3, Y2O3, BeO, WO3, Rb2O, Ir2O3; or the metal material is at least one of W, Re, Ru, Pt, Zr; the negative electrode of the extraction power supply is connected to the outer convex liquid surface of the electron emission material through the inner wall of the refractory container, and the positive electrode of the extraction power supply is connected to the annular extraction electrode; the extraction power supply is an adjustable DC voltage source, and its output voltage is between 0V and 6kV.

[0011] Optionally, the melting temperature of the refractory container is higher than the melting temperature of the electron emission material and the operating temperature of the electron emission device, and the melting temperature of the electron emission material is lower than the operating temperature of the electron emission device.

[0012] Optionally, the electron emission device further comprises a heating device, which is disposed on a side wall of the refractory container and is used to heat the refractory container and the electron emission material therein.

[0013] Optionally, the electron emission device described above is used, and the electronic device includes at least one of a vacuum electron tube, an X-ray generator, an electronic display and a thermoelectric transducer.

[0014] According to the specific embodiments provided in this application, this application discloses the following technical effects:

[0015] In the embodiment of the present disclosure, the through holes are micron-scale through holes formed by micro-nano processing technology, and the diameter of the through holes is between 0.1um and 100um. When the electron emission material is melted by heat and passes through these tiny through holes to form an arc-shaped convex liquid surface and emit electrons outward, the field emission effect of electrons is improved. A plurality of through holes are arranged at the bottom of the refractory container to form an electron emission array, which improves the consistency of the product structure and facilitates debugging. The life of the electron emission structure is proportional to the mass of the electron emission material contained therein, so that the electron generation life can be significantly extended compared to the life of traditional thermal field emission and cold field emission filaments. The heating power supply is connected to the outer wall of the refractory container to simplify the heating process, which can meet the application of electron beam exposure machines, scanning electron microscopes, transmission electron microscopes and other X-ray sources. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present application or related technologies, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0017] Figure 1 Schematic diagram of the structure of the electron emission device according to the embodiment of the present disclosure.

[0018] Figure 2 A schematic diagram of forming a needle tip for an electron emission device according to an embodiment of the present disclosure.

[0019] Figure 3 FIG. 4 is a functional schematic diagram of an electron emission device according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical solution and advantages of the embodiments of the present disclosure clearer, the technical solution of the embodiments of the present disclosure will be clearly and completely described below in conjunction with the drawings of the embodiments of the present disclosure. Obviously, the described embodiments are part of the embodiments of the present disclosure, not all of the embodiments. Based on the described embodiments of the present disclosure, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present disclosure.

[0021] Unless otherwise defined, the technical terms or scientific terms used in the present disclosure should be understood by people with ordinary skills in the field to which the present disclosure belongs. The "first", "second" and similar words used in the present disclosure do not indicate any order, quantity or importance, but are only used to distinguish different components. "Include" or "comprise" and similar words mean that the elements or objects appearing before the word cover the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0022] In order to keep the following description of the embodiments of the present disclosure clear and concise, the present disclosure omits detailed descriptions of well-known functions and well-known components.

[0023] The embodiments of the present disclosure relate to an electron emission device, which is mainly used in electron microscopes and electron beam exposure technology, and can also be used in vacuum electron tubes, X-ray generators, electronic displays, thermoelectric transducers and other devices. Figure 1 As shown, the embodiment of the present disclosure relates to an electron emission device 100, which can be set at the top of the electron lens barrel of a scanning electron microscope, a transmission electron microscope, an electron beam exposure machine, etc.; specifically, the electron emission device 100 includes a refractory container 1, the cross section of the refractory container 1 can be circular, or can be rectangular, oblong, elliptical, etc. The refractory container 1 has a cavity 11, where the cavity 11 is a vacuum cavity with a certain vacuum degree, where the cavity 11 can be a circular cavity, and its inner diameter is in the range of 1um to 100um. An electron emission material 2 is set in the cavity 11 of the refractory container 1, and the electron emission material 2 has a fixed melting temperature.

[0024] Furthermore, the refractory container 1 is made of a material with a relatively high melting temperature, such as a metal material. The melting temperature of the material of the refractory container 1 is higher than the melting temperature of the electron emission material 2 and also higher than the operating temperature of the electron emission device 100. The melting temperature of the electron emission material 2 is lower than the operating temperature of the electron emission device 100. Thus, when the electron emission device 100 is operating, the electron emission material 2 will melt into a liquid state, while the refractory container 1 will not be melted. It should be noted that between room temperature and the melting temperature of the refractory container 1, no chemical reaction occurs between the electron emission material 2 and the material of the refractory container 1, and no alloy is formed.

[0025] Further, the electron emission material 2 here refers to a material that absorbs a certain amount of energy, thereby causing electrons to escape from the constraints of atomic nuclei and be emitted from atoms. The electron emission material 2 here can be a semiconductor material. As a preferred embodiment, a semiconductor material with a low work function, such as GaAs, InP, etc., can be used. The energy band gap of such a material at room temperature is between 0.2eV and 5eV; in addition, the electron emission material 2 can also be an electrical insulating material. As a preferred embodiment, an oxide material with a low work function, such as CsO2, Zr2O3, Y2O3, BeO, WO3, Rb2O, Ir2O3, etc. can be used; of course, the electron emission material 2 can also be a metal material. As a preferred embodiment, a metal material with a low work function, such as W, Re, Ru, Pt, Zr, etc. can be used.

[0026] Furthermore, at least one through hole 3 is provided at the bottom of the refractory container 1, and the electron emission material 2 realizes electron emission outward from the through hole 3. The through hole 3 here is a micron-level through hole formed by micro-nano processing technology, and the diameter of the through hole 3 is between 0.1um and 100um. The micro-nano processing technology can make the structure processed with a high degree of consistency. In another embodiment, a plurality of through holes 3 can be provided at the bottom of the refractory container 11, and the plurality of through holes 3 can be provided so as to form an electron emission array.

[0027] In actual application, under the same working voltage, the intensity of the electrons emitted by the liquid electron source is related to the curvature of the convex liquid surface formed by the liquid at the bottom of the through hole. The greater the curvature, the higher the electric field at the top of the liquid surface, and the higher the emitted electron beam. Generally, the radius of curvature of the convex liquid surface is smaller than the radius of the through hole. The smaller the aperture of the through hole, the better the liquid electron emission effect. To maintain the mechanical strength of the container at high temperatures, its material needs to be a metal material with high hardness and high melting point, and the bottom thickness needs to reach a certain thickness, such as 200um or thicker. When a through hole with a diameter of less than 100um is selected, mechanical processing cannot meet the product processing accuracy. If a through hole with a diameter of less than 10um is selected, the mechanical processing method cannot meet the requirements. Therefore, the through hole with a diameter of 0.1um-100um implemented by the micro-nano processing technology implemented in the present disclosure can achieve product consistency and high electron emission performance of high-efficiency liquid electron emission devices.

[0028] In the range of 0.1um-100um in diameter, silicon wafers are used as substrates, and micro-nano processing processes such as photolithography and silicon deep etching can be used to manufacture through-hole templates. After electroplating seed layer deposition, container metal electroplating and silicon substrate etching, the bottom structure of the container with a through-hole with a high aspect ratio can be manufactured. Compared with mechanical processing, the advantages of micro-nano processing are:

[0029] 1) It is possible to manufacture through-hole structures with a high aspect ratio and a diameter of 0.1um-100um.

[0030] 2) Micro-nano manufacturing precision is higher than mechanical processing, which can ensure the consistency of product performance.

[0031] 3) It is easy to manufacture through-hole arrays, and the array period can be between 10um-200um.

[0032] 4) Realize wafer-level production of multiple liquid electron emission filament containers to improve production efficiency.

[0033] In addition, the electron emission device 100 also includes a heating device 4 and a heating power supply 6. The heating device 4 is arranged on the side wall of the refractory container 1, and is used to heat the refractory container 1 and the electron emission material 2 therein. It can be, for example, a device such as a resistance wire; the heating power supply 6 is connected to the heating device 4 to provide electrical energy to heat the electron emission material 2 in the refractory container 1 to its melting temperature or above through the heating device 4. It is arranged outside the refractory container 1, and it adjusts the power to adjust the electrical energy provided to the heating device 4, wherein the heating power supply 6 is a constant voltage DC power supply, and its output current is between 0A and 10A.

[0034] In some embodiments, if the refractory container 1 is made of a conductive material, such as a metal material, the heating device 4 may not be provided, and the heating power supply 6 may be directly connected to the outer wall of the refractory container 1, so that the electron emission material 2 in the refractory container 1 can be heated to its melting temperature or above by adjusting the power.

[0035] As described above, when the electron emission material 2 is heated to or above its melting temperature, the electron emission material 2 will be in a liquid state after melting, and the liquid electron emission material 2 will pass through the through hole 3 under the action of gravity and the like to form an arc-shaped convex liquid surface 8. Specifically, since the operating temperature range of the electron emission device 100 is higher than the melting temperature of the electron emission material 2, the liquid will have an infiltration effect with the solid between the melting temperature of the electron emission material 2 and the operating temperature of the electron emission device 100, that is, the liquid electron emission material 2 will form an arc-shaped convex liquid surface 8 at the opening of the through hole 3 after passing through the through hole 3 under the action of gravity and the like.

[0036] In this way, when the electron emission material 2 reaches the melting temperature, i.e., melts due to heat, the liquid electron emission material 2 passes through the through hole 3 of the refractory container 1 under the wetting effect between the solid and the liquid on the side wall of the through hole 3 under the action of gravity or capillary force, and forms an arc-shaped convex liquid surface 8 at the opening of the through hole 3. The convex liquid surface 8 can emit an electron beam under the action of a strong electric field. Further, as Figure 2 As shown, the convex liquid surface 8 can be further stretched into a droplet structure with a smaller radius under the action of a high electric field, that is, a structure of a liquid needle tip 9 is formed, thereby further enhancing the local electric field and generating a field emission effect of electrons.

[0037] In order to construct an electric field to facilitate the convex liquid surface 8 to emit an electron beam, a corresponding annular extraction electrode 5 is arranged below each through hole 3, and the extraction electrode 5 is arranged opposite to the convex liquid surface 8, that is, the central axis of the extraction electrode 5 coincides with the symmetry axis of the convex liquid surface 8. The spacing between the through hole 3 and the extraction electrode 5 is 50um to 5000um; wherein the extraction electrode 5 has an annular structure, and the inner diameter of the annular structure is 1um to 100um.

[0038] Furthermore, the electron emission device 100 further includes an extraction power source 7, which can be arranged outside the refractory container 1, the negative electrode of the extraction power source 7 is connected to the outer convex liquid surface 8 of the electron emission material 2 through the inner wall of the refractory container 1, and the positive electrode of the extraction power source 7 is connected to the annular extraction electrode 5. The extraction power source 7 is an adjustable DC voltage source, and its output voltage is between 0V and 6kV.

[0039] In the embodiment of the present disclosure, the convex liquid surface can be formed by using the combination of the melted liquid of the electron emission material and the through hole, and the convex liquid surface forms a liquid needle tip under the action of a strong DC electric field, thereby expanding the selection range of electron emission materials. The structural life of this electron emission device is proportional to the mass of the electron emission material contained, so the electron emission life of the electron emission device can be much longer than the life of the traditional thermal field emission and cold field emission filaments.

[0040] In the process of using the electron emission device 100 of the embodiment of the present disclosure, Figure 3 As shown, it can be carried out in the following manner: if it is in a scanning electron microscope, a transmission electron microscope and an electron beam exposure machine, the refractory container 1 in the electron emission device 100 is set at the top of the electron lens barrel therein, and the electron emission material 2 in the above embodiment is further set in the cavity 11 of the refractory container 1, and the heating power supply 6 is connected to the heating device 5 and the heating device 5 is connected to the refractory container 1. If the refractory container 1 is made of metal material, the heating power supply 6 can be directly connected to the refractory container 1.

[0041] Further, the cavity 11 of the refractory container 1 located at, for example, the top of the electron lens barrel is evacuated to a high vacuum state. For example, after the vacuum degree in the cavity 11 is adjusted to 1 micropascal, the power V1 of the heating power supply 6 is adjusted until the temperature of the electron emission material 2 reaches the melting temperature, so that the electron emission material 2 begins to melt, and then the power V1 of the heating power supply 6 is slowly increased until the electron emission material 2 melted to a liquid state in the refractory container 1 passes through the through hole 3 at the lower end of the refractory container 1 and continues to fall under the action of gravity or capillary force. In this way, at the lower end opening of the through hole 3, a stable arc-shaped convex liquid surface 8 is formed due to the wetting effect between the liquid electron emission material 2 and the solid through hole 3 and the liquid surface energy. Then, the voltage of the extraction power supply 7 is continued to be slowly increased, so that a strong electric field is formed under the action of the extraction electrode 7, and the convex liquid surface 8 emits an electron beam under the action of the strong electric field, thereby achieving the purpose of electron emission. Of course, the convex liquid surface 8 can also form a stable liquid needle tip 9 under the action of a strong electric field and liquid surface energy. The liquid needle tip 9 can further enhance the local electric field strength, thereby increasing the field emission effect of the emitted electron beam and achieving the purpose of forming a high-brightness electron emission device.

[0042] Here, in the process of emitting electron beams through the electron emission device, the capillary action of the liquid, the structure of the micron-level capillary channel, the wetting effect of the material, the electric field effect, etc. are used. It has a high electron field emission effect, a high degree of structural consistency, and easy debugging. The life of the electron emission structure is proportional to the mass of the electron emission material contained, so that the electron generation life can be significantly extended compared to the traditional thermal field emission and cold field emission filament life.

[0043] An embodiment of the present disclosure also provides an electronic device, which adopts the electron emission device in any of the above technical solutions, and the electronic device here includes at least one of a vacuum electron tube, an X-ray generator, an electronic display and a thermoelectric transducer.

[0044] The above description is only a preferred embodiment of the present disclosure and an explanation of the technical principles used. Those skilled in the art should understand that the scope of disclosure involved in the present disclosure is not limited to the technical solutions formed by a specific combination of the above technical features, but should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the above disclosed concept. For example, the above features are replaced with the technical features with similar functions disclosed in the present disclosure (but not limited to) by each other to form a technical solution.

[0045] In addition, although each operation is described in a specific order, this should not be understood as requiring these operations to be performed in the specific order shown or in a sequential order. Under certain circumstances, multitasking and parallel processing may be advantageous. Similarly, although some specific implementation details are included in the above discussion, these should not be interpreted as limiting the scope of the present disclosure. Some features described in the context of a separate embodiment can also be implemented in a single embodiment in combination. On the contrary, the various features described in the context of a single embodiment can also be implemented in multiple embodiments individually or in any suitable sub-combination mode.

[0046] Although the subject matter has been described in language specific to structural features and / or methodological logical actions, it should be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or actions described above. On the contrary, the specific features and actions described above are merely example forms of implementing the claims.

[0047] Multiple embodiments of the present disclosure are described in detail above, but the present disclosure is not limited to these specific embodiments. Those skilled in the art can make various variations and modifications to the embodiments based on the concepts of the present disclosure, and these variations and modifications should all fall within the scope of protection required by the present disclosure.

Claims

1. An electron emission device, characterized in that: The electron emission device comprises: a refractory container, a heating power supply and an extraction power supply; The refractory container has a cavity portion, and the cavity portion has a certain degree of vacuum; the cavity portion is a circular cavity, and its inner diameter is in the range of 1um to 100um; The heating power supply is connected to the outer wall of the refractory container, and the heating power supply heats the electron emission material in the refractory container to a melting temperature or above by adjusting the power; the refractory container is made of conductive material; the heating power supply is a constant voltage DC power supply, and its output current is between 0A and 10A; An electron emission material is arranged in the cavity portion, and at least one through hole is arranged at the bottom of the refractory container. After the electron emission material is heated and melted, it passes through the through hole to form an arc-shaped convex liquid surface and realizes electron emission outward; the convex liquid surface is further stretched out into a droplet structure with a smaller radius under the action of a high electric field to form a liquid needle tip structure, thereby further enhancing the local electric field and generating a field emission effect of electrons; a corresponding annular lead-out electrode is arranged below each of the through holes, and the lead-out electrode is arranged opposite to the convex liquid surface; the spacing between the through hole and the lead-out electrode is 50um to 5000um; the inner diameter of the annular lead-out electrode is 1um to 100um; the refractory A plurality of through holes are arranged at the bottom of the fire container to form an electron emission array; the through holes are micrometer-level through holes formed by micro-nano processing technology, and the diameter of the through holes is between 0.1um and 100um; the electron emission material does not chemically react with the material of the refractory container and will not form an alloy; the electron emission material is at least one of a semiconductor material, an electrical insulating material, and a metal material; the semiconductor material is GaAs or InP; or the electrical insulating material is at least one of CsO2, Zr2O3, Y2O3, BeO, WO3, Rb2O, and Ir2O3; or the metal material is at least one of W, Re, Ru, Pt, and Zr; The negative pole of the extraction power supply is connected to the outer convex liquid surface of the electron emission material through the inner wall of the refractory container, and the positive pole of the extraction power supply is connected to the annular extraction electrode; the extraction power supply is an adjustable DC voltage source, and its output voltage is between 0V and 6kV.

2. The electron emission device according to claim 1, characterized in that The melting temperature of the refractory container is higher than the melting temperature of the electron emission material and the operating temperature of the electron emission device, and the melting temperature of the electron emission material is lower than the operating temperature of the electron emission device.

3. The electron emission device according to claim 1, characterized in that The electron emission device further comprises a heating device, which is disposed on a side wall of the refractory container and is used to heat the refractory container and the electron emission material therein.

4. An electronic device, characterized in that: The electron emission device described in any one of claims 1 to 3 is used, wherein the electron device comprises at least one of a vacuum electron tube, an X-ray generator, an electronic display and a thermoelectric transducer.

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