Electron emission device and electronic device

Abstract

An electron emission device and an electronic device are proposed in the present disclosure. The electron emission device includes a refractory container and a heating power source. An electron emission material is provided in the cavity portion, and an electron extraction electrode plate is provided below the refractory container. Embodiments of the present disclosure have a relatively high field emission effect of electrons, the consistency of the electron beams of different emission arrays is increased, manufacturing a liquid needle tip using a liquid and a cavity can expand the selection range of the electron emission material, the action of the electron extraction electric field further pulls a liquid needle structure with a smaller radius, improves the field emission effect of electrons, and can significantly increase the efficiency of electron microscopes and electron beam lithography. The life of the electron emission structure is proportional to the quality of the electron emission material it contains. As a result, the electron generation life is significantly extended compared to the life of conventional thermionic emission filaments and cold field emission filaments, and it can meet the applications to electron beam lithography machines, scanning electron microscopes, transmission electron microscopes, and other X-ray sources.

Description

Technical Field

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

Background Art

[0002] Electron emission devices are important modern inventions. Applications in people's daily lives include cathode ray tube displays and electron beam tubes that accelerate an electron beam to a high voltage and then collide with heavy metals to generate X-rays. Cathode ray tube displays have basically disappeared from people's daily lives, but the X-ray sources excited by electron emission devices are still widely applied in medical devices such as chest X-ray examinations and CT scans. Vacuum electron tubes manufactured from electron emission devices play a very important role in high-frequency and high-power microwave technologies such as radar. In scientific research, scanning electron microscopes, transmission electron microscopes, mass spectrometry instruments, etc. cannot do without electron emission devices, and electron beam lithography machines, which are devices for manufacturing photolithography masks in modern chip production technology, also cannot do without electron emission devices.

[0003] In conventional electron generation devices, the main physical mechanisms include photoexcitation, thermal excitation, electric field excitation, secondary electron generation, or a combination thereof. Among them, photoexcitation electron generation technology is mainly used in photomultiplier tubes, and in scanning electron microscopes and electron beam lithography technology, thermal excitation and electric field excitation technologies are mainly used, especially thermionic emission and cold field electron emission technologies. The thermionic emission technology can output a very stable and high electron beam for a long time, so it is widely applied to electron beam lithography machines, high-end scanning electron microscopes, and transmission electron microscopes. The current thermionic emission electron beam device is a thermionic 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, a chemically etched tungsten single crystal is adopted to form a needle tip with a very large aspect ratio. To ensure the strong electric field required for field emission, its tip radius is within 100 nm. Its disadvantages include: 1) The repeatability of the geometric dimensions of the needle tip processed from a chemically etched tungsten single crystal is poor, and the consistency of electron emission of the processed filament is not high, so installation and debugging are troublesome; 2) The filament has large geometric dimensions. Usually, the diameter after the electron microscope filament is assembled is 1 - 2 cm. Such a filament is difficult to be arrayed and installed in an electron microscope or an electron beam lithography machine; 3) The filament has a relatively short lifespan, generally about 10,000 hours; 4) Defects and adsorption in the tungsten needle tip after chemical etching can cause instability and failure of the filament-emitted electron beam; 4) Due to the conventionally adopted needle tip manufacturing process, its materials are currently limited to a few materials such as W and LaB6, and the selection range of materials for electron beam emission devices is restricted.

Summary of the Invention

[0004] Embodiments of the present disclosure have been made in view of the above, and an electron emission device and an electronic device have been proposed to solve the drawbacks of insufficient consistency of conventional solid heat release or thermionic emission filament products, difficulty in manufacturing a compact array of filaments, short lifespan, etc.

[0005] The present disclosure provides an electron emission device including a refractory container having a cavity portion with a certain degree of vacuum and a heating power source. An electron emission material is provided in the cavity portion, and a plurality of through holes are provided at the bottom of the refractory container. After the electron emission material receives heat and melts, it passes through the through holes to form an arcuate convex liquid surface outward, and electron emission to the outside is realized. Below the refractory container, an electron extraction electrode plate is provided with a cavity for passing electrons. The through holes and the cavity correspond one-to-one, and an electron extraction electric field for accelerating electrons is formed between the refractory container and the electron extraction electrode plate.

[0006] In some embodiments, it further includes a lead-out power source in which the negative electrode is connected to the convex liquid surface of the electron emission material through the inner wall of the refractory container, and the positive electrode is connected to the electron extraction electrode plate.

[0007] In some embodiments, the pitch range between the refractory container and the electron extraction electrode plate is 50um - 5000um.

[0008] In some embodiments, the axis of the cavity is collinear with the axis of the corresponding through hole.

[0009] In some embodiments, the refractory container has a melting temperature higher than the melting temperature of the electron emission material and the operating temperature of the electron emission device, and the electron emission material has a melting temperature lower than the operating temperature of the electron emission device.

[0010] In some embodiments, the refractory container has a cross-section that is at least one of circular, rectangular, square, and elliptical, and the cavity portion is a circular cavity.

[0011] In some embodiments, the electron-emitting material is at least one of a semiconductor material, an electrical insulating material, and a metallic material.

[0012] In some embodiments, 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 metallic material is at least one of W, Re, Ru, Pt, and Zr.

[0013] In some embodiments, a plurality of the through holes are provided at the bottom of the refractory container, and forming the electron emission array can be facilitated by providing the plurality of through holes.

[0014] In some embodiments, it is provided on the side wall of the refractory container and further includes a heating device for heating the refractory container and the electron-emitting material therein.

[0015] The present disclosure further provides an electronic device employing the electron-emitting device according to any one of the above claims, the electronic device including at least one of a vacuum electron tube, an X-ray generator, an electronic display, and a thermoelectric converter.

[0016] Embodiments of the present disclosure have a relatively high field emission effect of electrons, a relatively high degree of consistency in product structure, easy debugging, high consistency of electron beams of different emission arrays, and the use of liquid and cavities to manufacture liquid tips can expand the selection range of electron emission materials. Under the action of the electron extraction electric field, a liquid needle structure with a smaller radius is further pulled, the local electric field is further increased, the field emission effect of electrons is improved, the efficiency of electron microscopes and electron beam lithography can be significantly increased, and the life of the electron emission structure is proportional to the quality of the electron emission material accommodated. As a result, the electron generation life is significantly extended compared to the life of conventional thermionic emission filaments and cold field emission filaments, and can meet the applications of electron beam lithography machines, scanning electron microscopes, transmission electron microscopes, and other X-ray sources.

Brief Description of the Drawings

[0017]

Figure 1

Figure 2

Figure 3

Modes for Carrying Out the Invention

[0018] To make the objectives, technical solutions, and advantages of the embodiments of the present disclosure clearer, the following will clearly and completely describe the technical solutions of the embodiments of the present disclosure in combination with the drawings of the embodiments of the present disclosure. It goes without saying that the embodiments described herein are only some, not all, of the embodiments of the present disclosure. All other embodiments obtained by those skilled in the art based on the embodiments of the present disclosure described herein without creative labor belong to the protection scope of the present disclosure.

[0019] Unless otherwise specified, technical terms or scientific terms used in this disclosure should have the ordinary meanings understood by those with ordinary skills in the field to which this disclosure belongs. The "first", "second" and similar terms used in this disclosure do not represent any order, number, or importance, but are only used to distinguish different components. Similar terms such as "comprising" or "included" mean that the elements or things appearing before this term cover the elements or things listed after this term and their equivalents without excluding other elements or things. Similar terms such as "connected" or "linked" are not limited to physical or mechanical connections, and can include electrical connections regardless of direct or indirect connections. Terms such as "above", "below", "left", "right" are only used to represent relative positional relationships, and when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0020] To clarify and simplify the following description of the embodiments of the present disclosure, the present disclosure omits detailed descriptions of known functions and known components.

[0021] Embodiments of the present disclosure relate to an electron emission device, where the electron emission device here is mainly applied to electron microscopes and electron beam lithography technology. Of course, it may also be used in devices such as vacuum electron tubes, X-ray generators, electronic displays, and thermoelectric converters. As shown in FIGS. 1 to 3, embodiments of the present disclosure relate to an electron emission device 100 that can be installed at the tip of the electron lens barrel of devices such as a scanning electron microscope, a transmission electron microscope, and an electron beam lithography machine. Specifically, the electron emission device 100 includes a refractory container 1, and the cross-section of the refractory container 1 may be circular, or may be other shapes such as rectangular, square, or elliptical. The refractory container 1 has a cavity portion 11, and the cavity portion 11 here is a vacuum chamber with a certain degree of vacuum. The cavity portion 11 here may be a circular cavity, and its inner diameter is in the range of 1 um to 100 um. An electron emission material with a certain melting temperature is provided in the cavity portion 11 of the refractory container 1.

[0022] Furthermore, the refractory container 1 here is made of a material with a high melting temperature, such as a metal material. The material of the refractory container 1 has a melting temperature higher than that of the electron-emitting material and higher than the operating temperature of the electron-emitting device 100. And the electron-emitting material has a melting temperature lower than the operating temperature of the electron-emitting device 100. Thus, when the electron-emitting device 100 operates, the electron-emitting material melts and becomes liquid, while the refractory container 1 does not melt. Note that between the room temperature and the melting temperature of the refractory container 1, no chemical reaction occurs between the electron-emitting material and the material of the refractory container 1, nor is an alloy formed.

[0023] Furthermore, the electron-emitting material here refers to a material that absorbs a certain amount of energy so that electrons are released from the bondage of the atomic nucleus and atoms are emitted. The electron-emitting material here may be a semiconductor material. Preferably, semiconductor materials with a low work function such as GaAs and InP can be used. Such materials have a band gap at room temperature between 0.2 eV and 5 eV. Also, the electron-emitting material may be an electrical insulating material. Preferably, oxide materials with a low work function such as CsO2, Zr2O3, Y2O3, BeO, WO3, Rb2O, and Ir2O3 can be used. Of course, the electron-emitting material may be a metal material. Preferably, metal materials with a low work function such as W, Re, Ru, Pt, and Zr can be used.

[0024] Furthermore, a plurality of through holes 3 are provided at the bottom of the refractory container 1. After the electron-emitting material receives heat and melts, it passes through the through holes 3 to form an arc-shaped convex liquid surface outward, and electron emission to the outside is realized. The through holes 3 here are micron-level through holes formed by micro-nano processing technology. The diameter of the through holes 3 is between 0.1 um and 100 um. By micro-nano processing technology, the consistency of the processed structure can be improved. Among them, by providing a plurality of through holes 3, the formation of an electron emission array can be facilitated.

[0025] In order to construct an electric field so that the convex liquid surface 8 is likely to emit an electron beam, an electron extraction electrode plate 2 with a cavity 21 for passing electrons is provided below the refractory container 1. The through holes 3 and the cavities 21 correspond to each other one by one. An electron extraction electric field 22 for accelerating electrons is formed between the refractory container 1 and the electron extraction electrode plate 2. After the electron-emitting material melts, due to the action of gravity or capillary force, it flows outside the through hole 3 through the through-hole array below the refractory container 1, and then receives the infiltration action of the side wall of the through hole 3, forming an arc-shaped convex surface outside each through hole 3. Each convex surface is further pulled by the action of the electron extraction electric field 22 to form a liquid needle structure with a smaller radius, further increasing the local electric field and improving the field emission effect of electrons. Each liquid needle constitutes an electron emission array as an electron emission source, and this array can emit a very large electron beam. If the electron sources emitted from each liquid needle are focused and then scanning and switching are realized, it can be used in a multi-beam scanning electron microscope or a multi-beam electron beam exposure device, and the efficiency of the electron microscope and electron beam exposure can be greatly improved.

[0026] Among them, the cavity 21 has a circular cross-section, and the diameter range of the cavity 21 is 1 um to 120 um.

[0027] Specifically, the electron emission device 100 may be installed separately from the refractory container 1, and further includes a lead-out power supply 7 whose negative electrode is connected to the convex liquid surface of the electron-emitting material through the inner wall of the refractory container 1 and whose positive electrode is connected to the electron extraction electrode plate 2. The lead-out power supply 7 is an adjustable DC voltage source with an output voltage between 0 V and 6 kV. The lead-out power supply 7 is used to establish an electron extraction electric field 22 between the refractory container 1 and the electron extraction electrode plate 2.

[0028] In some embodiments, the pitch range between the refractory container 1 and the electron extraction electrode plate 2 is 50 um to 5000 um.

[0029] In some embodiments, the axis of the cavity 21 is collinear with the axis of the corresponding through hole 3. More specifically, the axis of the cavity 21 overlaps with the axis of symmetry of the corresponding arcuate convex liquid surface. After the liquid needle is formed, the tip of the liquid needle can surely point to the middle part of the cavity 21, ensuring the emission of electrons.

[0030] Further, the electron emission device 100 includes a heating device 4 provided on the side wall of the refractory container 1, which can be, for example, a resistance wire or the like for heating the refractory container 1 and the electron emission material therein, and a heating power supply 6 connected to the heating device 4. The heating power supply 6 supplies electrical energy to heat the electron emission material in the refractory container 1 to a temperature above its melting temperature. The heating power supply 6 is provided separately from the refractory container 1 and adjusts the electrical energy supplied to the heating device 4 by adjusting the power. Here, the heating power supply 6 is a constant voltage DC power supply with an output current between 0 A and 10 A.

[0031] Among them, in some embodiments, when the refractory container 1 is made of a conductive material, for example, 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, and the electron emission material in the refractory container 1 may be heated to a temperature above its melting temperature by adjusting the power.

[0032] As described above, after the electron emission material is heated to a temperature above its melting temperature, the electron emission material melts and becomes liquid. The liquid electron emission material passes through the through hole 3 under the action of gravity or the like to form an arcuate 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, there is an infiltration effect between the liquid and the solid from the melting temperature of the electron emission material to the operating temperature of the electron emission device 100. That is, the liquid electron emission material forms the arcuate convex liquid surface 8 at the opening of the through hole 3 after passing through the through hole 3 under the action of gravity or the like.

[0033] In this way, after the electron-emitting material reaches its melting temperature, that is, after it melts upon receiving heat, due to the infiltration effect between the solid and liquid on the side wall of the through-hole 3, the electron-emitting material in a liquid state forms, under the action of gravity or capillary force, an arc-shaped convex liquid surface 8 at the opening of the through-hole 3 after passing through the through-hole 3 of the refractory container 1 based on the infiltration effect on the side wall 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 shown in FIG. 3, the convex liquid surface 8 can be further pulled by a high electric field to form a droplet structure with a smaller radius, that is, the structure of a liquid tip 9, thereby further increasing the local electric field and improving the field emission effect of electrons. Each liquid tip in the electron emission array emits high-brightness electrons, and the liquid tip array emits a high-brightness electron source array, thus realizing a high-brightness electron emission source array.

[0034] In an embodiment of the present disclosure, by the combination of the melted liquid of the electron-emitting material and the through-hole 3, the convex liquid surface 8 can be formed. The convex liquid surface 8 forms a liquid tip 9 under the action of a strong direct current electric field, and the selection range of the electron-emitting material can be expanded. The structural life of such an electron emission device 100 is proportional to the quality of the electron-emitting material contained therein. Therefore, the electron emission life of the electron emission device 100 may be significantly longer than the lives of conventional thermionic emission filaments and cold field emission filaments.

[0035] In the process of adopting the electron emission device 100 according to the embodiment of the present disclosure, referring to the contents shown in FIGS. 1 to 3, it can be implemented as follows. That is, in the case of a scanning electron microscope, a transmission electron microscope, or an electron beam lithography machine, the refractory container 1 in the electron emission device 100 is installed at the tip of the electron lens barrel therein, and further, the electron-emitting material in the above embodiment is provided in the cavity portion 11 of the refractory container 1. The heating power supply 6 is connected to the heating device 5, and the heating device 5 is connected to the refractory container 1. However, when the refractory container 1 is made of a metal material, the heating power supply 6 may be directly connected to the refractory container 1.

[0036] Furthermore, for example, the cavity portion 11 of the refractory container 1 located at the tip of the electron lens barrel is evacuated to a high vacuum state. For example, after adjusting the degree of vacuum in the cavity portion 11 to 1 micropascal, the power V1 of the heating power supply 6 is adjusted until the temperature of the electron-emitting material reaches the melting temperature. Then, the electron-emitting material starts to melt in this way, and until the melted electron-emitting material in a liquid state in the refractory container 1 continues to fall through the through hole 3 at the lower end of the refractory container 1 under the action of gravity or capillary force, the power V1 of the heating power supply 6 is gradually increased. In this way, due to the combined action of the infiltration action between the liquid electron-emitting material and the solid through hole 3 at the lower end opening of the through hole 3 and the liquid surface energy, a stable arcuate convex liquid surface 8 is formed. Then, a strong electric field is formed under the action of the extraction power supply 7, and the convex liquid surface 8 emits an electron beam under the action of the strong electric field. Subsequently, the voltage of the extraction power supply 7 is gradually increased to achieve the purpose of electron emission. Of course, the convex liquid surface 8 can also form a stable liquid tip 9 under the action of the strong electric field and the liquid surface energy. The liquid tip 9 can further increase the local electric field strength and improve the field emission effect of the electron beam emission, thereby achieving the purpose of forming a high-brightness electron emission device. At this time, an array of liquid tips 9 is formed outside the array of through holes 3, and each liquid tip 9 in the array emits high-brightness electrons. The array of liquid tips 9 emits a high-brightness electron source array, and a high-brightness electron emission source array is realized.

[0037] Here, in the process of emitting an electron beam by the electron emission device, by utilizing the capillary action of the liquid, the structure of the micron-level capillary pipeline, the infiltration action of the material, the electric field effect, etc., it has a relatively high field emission effect of electrons, a relatively high degree of structural consistency, is easy to debug, and the service life of the electron emission structure is proportional to the quality of the electron-emitting material that accommodates it. Thereby, the electron generation life can be significantly extended compared to the service lives of the conventional thermionic emission filament and the cold field emission filament.

[0038] Embodiments of the present disclosure further provide an electronic device employing an electron-emitting device in the technical solution of any one of the above items. Here, the electronic device includes at least one of a vacuum electron tube, an X-ray generator, an electronic display, and a thermoelectric converter.

[0039] The above description is only an explanation of the preferred embodiments of the present disclosure and the technical principles applied. The scope of the disclosure according to the present disclosure is not limited to the technical solutions formed by specific combinations of the above technical features. It should be understood by those skilled in the art that other technical solutions formed by arbitrarily combining the above technical features or their equivalent features should also be covered when not departing from the above disclosure idea. For example, it is a replacement of the above features with technical features having similar functions (but not limited to this) disclosed in the present disclosure.

[0040] Also, although each operation is depicted in a specific order, it should not be understood as being required to be performed in the shown specific order or sequentially. In certain environments, multitasking and parallel processing may be advantageous. Similarly, although the above discussion includes some specific implementation details, it should not be construed as a limitation on the scope of the present disclosure. Some features described in the context of individual embodiments may be implemented in combination in a single embodiment. Conversely, various features described in the context of a single embodiment may be implemented separately or in any suitable sub-combination in multiple embodiments.

[0041] Although this subject matter has been described using specific words for structural features and / or methodological logical operations, it should be understood that the subject matter defined by the appended claims is not necessarily limited to the specific features or operations described above. Conversely, the above specific features and operations are merely exemplary forms for implementing the claims.

[0042] Although some embodiments of the present disclosure have been described in detail above, the present disclosure is not limited to these specific embodiments, and those skilled in the art can make various changes and modifications to the embodiments based on the idea of the present disclosure, and these variations and modifications should be included in the scope of the present disclosure.

Claims

1. An electron emission device including a refractory container having one cavity portion with a certain degree of vacuum, and a heating power source, wherein an electron emission material is provided in the cavity portion, a plurality of through holes are provided at the bottom of the refractory container, and after the electron emission material receives heat and melts, it passes through the through holes to form an arcuate convex liquid surface outward, and electron emission to the outside is realized, below the refractory container, an electron extraction electrode plate is provided with a cavity for passing electrons, the through holes and the cavity correspond one-to-one, an electron extraction electric field for accelerating electrons is formed between the refractory container and the electron extraction electrode plate, characterized in that it is an electron emission device.

2. Further including a lead-out power source in which the negative electrode is connected to the convex liquid surface of the electron emission material through the inner wall of the refractory container, and the positive electrode is connected to the electron extraction electrode plate, characterized in that it is the electron emission device according to Claim 1.

3. The pitch range between the refractory container and the electron extraction electrode plate is 50 μm to 5000 μm, characterized in that it is the electron emission device according to Claim 1.

4. The axis of the cavity is collinear with the axis of the corresponding through hole, characterized in that it is the electron emission device according to Claim 1.

5. The refractory container has a melting temperature higher than the melting temperature of the electron emission material and the operating temperature of the electron emission device, and the electron emission material has a melting temperature lower than the operating temperature of the electron emission device, characterized in that it is the electron emission device according to Claim 1.

6. The refractory container has at least one of a circular, rectangular, rectangular, or elliptical cross section, the cavity portion is a circular cavity, characterized in that it is the electron emission device according to Claim 1.

7. The electron emission material is at least one of a semiconductor material, an electrical insulating material, and a metal material, characterized in that it is the electron emission device according to Claim 1.

8. The semiconductor material is GaAs or InP, Alternatively, the electrical insulating material is CsO ２ , Zr ２ O ３ , Y ２ O ３ , BeO, WO ３ , Rb ２ O, Ir ２ O ３ and is at least one of them, alternatively, the metal material is at least one of W, Re, Ru, Pt, Zr, characterized in that it is the electron emission device according to Claim 7.

9. Further including a heating device provided on the side wall of the refractory container for heating the refractory container and the electron emission material therein, characterized in that it is the electron emission device according to Claim 1.

10. An electronic device employing the electron-emitting device according to any one of claims 1 to 9, comprising at least one of a vacuum electron tube, an X-ray generator, an electronic display, and a thermoelectric converter. An electronic device characterized by the above.

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