Emitter and electron gun

Abstract

This emitter comprises an emission member (10) that has a tip (100) from which charged particles are emitted. The emission member (10) comprises a base part (19) and an emission part (18). The base part (19) has a side surface (191) and an end surface (192). The emission part (18) protrudes from the end surface (192) of the base part (19) and emits charged particles from the tip (100). Furthermore, the side surface (191) and the end surface (192) are connected via an inclined surface (193) that is inclined with respect to both the side surface (191) and the end surface (192).

Description

Emitter and electron gun

[0001] This invention relates to an emitter and an electron gun.

[0002] Emitters, which release charged particles such as electrons and ions, are used in microscopes, inspection equipment, processing equipment, and the like.

[0003] Patent Document 1 describes a method for manufacturing an emitter, in which a single-crystal material fixed to a support is processed with a focused ion beam to give the ends of the single-crystal material a tapered shape.

[0004] International Publication No. 2021 / 079855

[0005] However, in the emitter described in Patent Document 1, the corners of the support fixed to the single crystal material could potentially adversely affect the electric field concentration at the edges of the single crystal material that are to emit electrons.

[0006] This invention provides a technology that can reduce the draw voltage by preventing electric field concentration at the tip of the emitter.

[0007] According to one embodiment of the present invention, the following emitter and electron gun are provided.

[0008] 1. An emitter comprising a discharge member having a tip for emitting charged particles, wherein the discharge member comprises a base portion having a side surface and an end surface, and a discharge portion protruding from the end surface of the base portion and emitting charged particles from the tip, wherein the side surface and the end surface are connected via an inclined surface that is oblique to both the side surface and the end surface. 2. An emitter according to 1, wherein the angle between the side surface and the inclined surface is 135° or more and 165° or less. 3. An emitter according to 1 or 2, wherein the side surface and the end surface are not directly connected. 4. An emitter according to any one of 1 to 3, wherein the angle between the side surface and the axis of the discharge member is 3° or less. 5. An emitter according to any one of 1 to 4, wherein the angle between the end surface and the side surface is 75° or more and 105° or less. 6. 1. An emitter according to any one of 1 to 5, wherein the inclined surface is a curved surface. 7. An emitter according to any one of 1 to 6, wherein, when viewed with the line of sight perpendicular to the side surface, the distance in the direction parallel to the axis of the emitter between the straight line passing through the point furthest from the tip and the point closest to the tip in the portion of the contour line of the emitter corresponding to the inclined surface, and the tip, is 15 μm or more. 8. An emitter according to any one of 1 to 7, wherein the base portion has four side surfaces. 9. An emitter according to any one of 1 to 8, wherein, when viewed with the line of sight perpendicular to the side surface, the maximum width of the base portion in the direction perpendicular to the axis of the emitter is 50 times or more the maximum width of the emitter in the direction perpendicular to the axis of the emitter. 10. 1 to 9. An emitter according to any one of the above, wherein the radius of curvature of the tip is 20 nm or more and 500 nm or less. 11. An emitter according to any one of the above from 1 to 10, wherein the emission member is MB ６An emitter comprising a crystal, wherein M is at least one of La and Ce. 12. An emitter according to 11, wherein the angle between the axis of the emission member and the <100> direction of the crystal is 5° or less. 13. An emitter according to any one of 1 to 12, wherein it is an electron emitter. 14. An emitter according to any one of 1 to 13, wherein it is a cold cathode. 15. An electron gun comprising an emitter according to any one of 1 to 14.

[0009] According to the present invention, electric field concentration is more likely to occur at the tip of the emitter, and a technology is provided that can reduce the extracted voltage.

[0010] This is a diagram illustrating the configuration of an emitter according to an embodiment. This is a diagram illustrating the configuration of an emitter according to an embodiment. This is a diagram illustrating the structure of an emission member. This is a diagram illustrating the structure of an emission member. This is a diagram showing an enlarged view of the structure of the tip and vicinity of the tip of the emission member. This is a diagram showing an enlarged view of the structure of the tip and vicinity of the tip of an emission member according to a modified example. This is a diagram for explaining distance d. This is a diagram illustrating the configuration of an electron gun according to an embodiment. This is a diagram showing the structure of an emission member according to a comparative example. This is a diagram showing the relationship between the extracted voltage and the total current measured using the emitters according to the example and comparative example.

[0011] Embodiments of the present invention will be described below with reference to the drawings. In all drawings, similar components are denoted by the same reference numerals, and their descriptions are omitted as appropriate.

[0012] Figures 1 and 2 illustrate the configuration of the emitter 50 according to the embodiment. Figures 3 and 4 illustrate the structure of the emission member 10.

[0013] The emitter 50 according to this embodiment includes an emission member 10 having a tip 100 that emits charged particles. The emission member 10 includes a base portion 19 and an emission portion 18. The base portion 19 has a side surface 191 and an end surface 192. The emission portion 18 protrudes from the end surface 192 of the base portion 19 and emits charged particles from the tip 100. The side surface 191 and the end surface 192 are connected via a slanted surface 193 that is oblique to both the side surface 191 and the end surface 192. This will be explained in detail below.

[0014] In the example shown in Figure 1, the emitter 50 further comprises a cup 21, a conductive member 30, an insulating member 40, a first terminal 41, and a second terminal 42.

[0015] In all figures, the x, y, and z axes are mutually orthogonal triaxial axes. Charged particles are emitted from the tip 100 of the emission member 10 in the +z direction. Figure 1 shows an example of the emitter 50 configuration as viewed with the +x direction as the line of sight. Figure 2 shows an example of the emitter 50 configuration as viewed with the -z direction as the line of sight. The first terminal 41 and the second terminal 42 are aligned in the y-axis direction.

[0016] In the discharge member 10, the side opposite to the tip 100 is called the root side. In the example shown in this figure, the axis 105 is parallel to the z-axis. The axis 105 can be said to be a straight line passing through the centroid of the first reference cross-section, which is the cross-section of the discharge member 10, and the centroid of the second reference cross-section of the discharge member 10. Here, the first reference cross-section is the cross-section of the discharge member 10 at a position 1 μm from the tip 100 toward the root. The second reference cross-section is the cross-section of the discharge member 10 at a position 2 μm from the tip 100 toward the root. The cross-section can be taken at multiple angles, but the first and second reference cross-sections are the cross-sections at the angles that result in the smallest cross-sectional area.

[0017] In the emission member 10, "thickness" corresponds to the area of ​​the cross-section perpendicular to the axis 105. In the emission member 10, "length" means the length in the direction parallel to the axis 105 (i.e., the length in the z-axis direction). In the emission member 10, "width" means the width in the direction perpendicular to the axis 105 (i.e., the length in the y-axis direction) of the contour of the emission member 10 as identified by observation with an electron microscope. The contour line of the emission member 10 can be identified, for example, using an image obtained by imaging the emission member 10 with an electron microscope, with the line of sight parallel to the x-axis.

[0018] Returning to Figure 1, the configuration of the emitter 50 will be explained in detail.

[0019] The emitter 50 is, for example, an electron emitter that emits electrons as charged particles. However, the emitter 50 may also be an emitter that emits ions as charged particles.

[0020] The emitter 50 is preferably a cold field emitter (CFE). In this case, the emitter 50 does not require heating of the emission member 10 and emits electrons by applying an electric field. However, the emitter 50 is not limited to a cold cathode and may be a thermal field emitter (TFE). When the emitter 50 is a cold cathode, a higher brightness electron beam can be obtained compared to when it is a thermal field emitter.

[0021] A portion of the base of the discharge member 10 is covered by the cup 21. The cup 21 is made of a metal such as tantalum and is conductive. The base portion of the discharge member 10 is located inside the cup 21. In other words, the other portion of the discharge member 10 protrudes and is exposed from the opening of the cup 21.

[0022] The cup 21 is fixed to the conductive member 30. That is, the emission member 10 is fixed to the conductive member 30. The conductive member 30 electrically connects the first terminal 41, the second terminal 42, and the emission member 10 to each other. In the example in Figures 1 and 2, the emitter 50 comprises two conductive members 30. One end of one conductive member 30 is fixed to the outer surface of the cup 21 facing the +x side, and the other end is fixed to the first terminal 41. One end of the other conductive member 30 is fixed to the outer surface of the cup 21 facing the -x side, and the other end is fixed to the second terminal 42. This stabilizes the potential of the emission member 10 and allows current to flow effectively through the cup 21. The cup 21 may be welded to the conductive member 30. The joint between the cup 21 and the conductive member 30 may be covered with conductive paste.

[0023] The conductive member 30 can be made from a material that is heat-resistant and electrically conductive. Examples of constituent elements of the conductive member 30 include tungsten, rhenium, molybdenum, platinum, aluminum, silicon, and potassium. The conductive member 30 is, for example, a metal wire. The diameter of the conductive member 30 can be, for example, 1 μm to 500 μm, from the viewpoint of easily ensuring the strength necessary to support the discharge member 10, or from the viewpoint of optimizing the resistance value of the conductive member 30.

[0024] The conductive member 30 may be a filament. The conductive member 30 can also be used, for example, to heat the emission member 10 in flushing. The conductive member 30 may be a tungsten filament, or a tungsten-rhenium (tungsten-rhenium alloy) filament. By passing current from the first terminal 41 through the conductive member 30 to the second terminal 42, the conductive member 30 can be heated, and consequently the emission member 10 can be heated. Flushing is an operation to restore the emitter 50 from a decrease in emission current. Examples of flushing include cleaning the emission member 10 by heating and cleaning the emission member 10 by field evaporation. Specifically, flushing by heating can be performed by passing current through the first terminal 41 and the second terminal 42 to the conductive member 30 and the emission member 10 to generate Joule heat.

[0025] The insulating member 40 is made of an insulating material such as resin or ceramic. The first terminal 41 and the second terminal 42 form a terminal pair. The first terminal 41 and the second terminal 42 are spaced apart from each other and penetrate the insulating member 40. In the examples in Figures 1 and 2, one conductive member 30 is fixed to the +x side of the first terminal 41, and the other conductive member 30 is fixed to the -x side of the second terminal 42. The distance between the first terminal 41 and the second terminal 42 in the y-axis direction is preferably 0.1 mm or more from the viewpoint of suppressing inter-terminal discharge, and preferably 10 mm or less from the viewpoint of easily miniaturizing the emitter 50.

[0026] The emission member 10 will be described in detail with reference to Figures 3 and 4. Figure 3 shows an example of the configuration of the emission member 10 as viewed with the +x direction as the line of sight. Figure 4 shows an example of the configuration of the emission member 10 as viewed with the -z direction as the line of sight. The emission member 10 comprises an emission section 18 and a base section 19. The emission section 18 has a tip 100 that emits charged particles. The base section 19 is connected to the end of the emission section 18 opposite to the tip 100. In the example in Figure 3, the emission section 18 and the base section 19 are adjacent to each other. That is, there are no other parts interposed between the emission section 18 and the base section 19.

[0027] The base portion 19 has, for example, a columnar shape such as a quadrangular prism shape or a cylindrical shape. The shape of a cross-section perpendicular to the axis 105 at at least any position of the base portion 19 may be circular or elliptical, or may be a polygon such as a triangle, a quadrangle, a pentagon, or a hexagon. When the emission member 10 includes the base portion 19, the handling property of the emission member 10 is improved, the connection strength with the conductive member 30 is improved, and the processability and processing efficiency of the tip 100 are improved.

[0028] From the viewpoint of handling properties, the length of the base portion 19 in the direction parallel to the axis 105 is preferably 100 µm or more. From the viewpoint of handling properties, in the thickest portion of the base portion 19, the area of the cross-section perpendicular to the axis 105 of the base portion 19 is 100 µm ２ or more is preferable. In the example of Fig. 1, a part of the base portion 19 of the emission member 10 is covered by the cup 21. The entire emission portion 18 is located outside the cup 21.

[0029] A side surface 191 of the base portion 19 may be a flat surface or a curved surface. Further, the base portion 19 may have both the flat side surface 191 and the curved side surface 191. The base portion 19 can have one or more side surfaces 191. When the base portion 19 is cylindrical, it can be said that the base portion 19 includes one curved side surface 191. When the base portion 19 includes a plurality of side surfaces 191, it is preferable that the preferable conditions related to the side surface 191 described below are satisfied for at least any one of the side surfaces 191, and it is more preferable that the conditions are satisfied for all the side surfaces 191.

[0030] From the viewpoint of handling properties, the side surface 191 and the axis 105 are preferably approximately parallel. That is, the angle formed between the side surface 191 and the axis 105 of the emission member 10 is preferably 3° or less, more preferably 2° or less, and even more preferably 1° or less. Note that the angle formed between a surface and the axis 105 means the smallest angle among the angles formed between the surface and the axis 105. That is, the angle formed between a surface and the axis 105 is represented by a value of 0° or more and 90° or less. The same applies to the following description.

[0031] The end face 192 is located on the distal end 100 side of the base portion 19. The end face 192 may be a flat surface or a curved surface. When the base portion 19 has a plurality of faces facing the +z side, the end face 192 means the face on which the emission portion 18 is formed. It is preferable that the end face 192 is approximately perpendicular to the axis 105. For example, an angle formed between the end face 192 and the axis 105 of the emission member 10 is preferably not less than 75° and not more than 90°. Further, it is preferable that the end face 192 is approximately perpendicular to the side face 191. For example, an angle α formed between the end face 192 and the side face 191 is preferably not less than 75°, more preferably not less than 80°, and still more preferably not less than 85°. The angle α formed between the end face 192 and the side face 191 is preferably not more than 120°, more preferably not more than 110°, and still more preferably not more than 105°.

[0032] The area of the end face 192 is not particularly limited, but for example, from the viewpoint of production efficiency, it is preferable that the area is not less than 1 / 350 and not more than 1 / 4 of the maximum cross-sectional area of the base portion 19 taken perpendicular to the axis 105.

[0033] The side surface 191 and the end surface 192 are connected via a bevel 193. This makes it easier for electric field concentration to occur at the tip 100 of the discharge member 10 compared to the case where there is no bevel 193, i.e., where the entire perimeter of the side surface 191 and the end surface 192 is directly connected and a sharp edge is formed. Consequently, the extracted voltage can be reduced. The bevel 193 is oblique to both the side surface 191 and the end surface 192. The orientation of the bevel 193 is not particularly limited, but the angle β between the side surface 191 and the bevel 193 is preferably 135° or more, more preferably 140° or more, and even more preferably 145° or more. The angle β between the side surface 191 and the bevel 193 is preferably 165° or less, more preferably 160° or less, and even more preferably 155° or less. The angle γ between the end face 192 and the inclined surface 193 is preferably 105° or more, more preferably 110° or more, and even more preferably 120° or more. The angle γ between the end face 192 and the inclined surface 193 is preferably 145° or less, and more preferably 135° or less. The side surface 191 and the end face 192 are preferably not directly connected, but they may be directly connected in part.

[0034] Preferably, the inclined surface 193 is formed over an area of ​​15% or more of the total length of the base portion 19 in a direction parallel to the axis.

[0035] In the examples shown in Figures 3 and 4, the base portion 19 has a shape in which a part of the tip 100 side of a rectangular prism is cut off with a conical surface. That is, the base portion 19 has four sides 191. The cross-sectional shape of the first portion of the base portion 19 perpendicular to the axis 105 is rectangular. The cross-sectional shape of the second portion of the base portion 19 perpendicular to the axis 105 is circular. The second portion is located closer to the tip 100 than the first portion. The inclined surface 193 connecting the base portion 19 and the discharge portion 18 is a curved surface oblique to the base portion 19 and the discharge portion 18, and more specifically, it is a conical surface. When viewed with the -z direction as the line of sight, the end face 192 is surrounded all around by the inclined surface 193.

[0036] The discharge section 18 has a columnar shape that extends in a direction parallel to the axis 105. The shape of the cross-section of the discharge section 18 perpendicular to the axis 105 may or may not be uniform. The shape of the cross-section perpendicular to the axis 105 at at least one position of the discharge section 18 may be circular or elliptical, or it may be a polygon such as a triangle, square, pentagon, or hexagon.

[0037] The boundary portion of the discharge portion 18 with the base portion 19 is thicker than the tip 100. When viewed with the line of sight in a direction parallel to the axis 105, it is preferable that the discharge portion 18 coincides with the centroid of the figure formed by the contour of the base portion 19. When viewed with the line of sight in a direction parallel to the axis 105, it is preferable that the discharge portion 18 coincides with the centroid of the figure formed by the contour of the end face 192.

[0038] In at least a portion of the discharge portion 18, the diameter of the discharge portion 18 tapers towards the tip 100. In at least a portion of the discharge portion 18, the diameter of the discharge portion 18 may be approximately constant along the axis 105. Note that the diameter of the discharge portion 18 being approximately constant means that the rate of change of the cross-sectional area in the direction parallel to the axis 105 is 400 nm. ２ This means that the particle size is less than or equal to / μm. Preferably, the discharge portion 18 does not have a portion that is thicker towards the tip 100. However, the discharge portion 18 may have a portion that is thicker towards the tip 100.

[0039] From the viewpoint of easily causing electric field concentration at the tip 100, the length of the discharge portion 18 in the direction parallel to the axis 105 is preferably 2 μm or more, more preferably 10 μm or more, and even more preferably 15 μm or more. From the viewpoint of ensuring the strength of the discharge portion 18, the length of the discharge portion 18 in the direction parallel to the axis 105 is preferably 300 μm or less, more preferably 200 μm or less, and even more preferably 150 μm or less.

[0040] The emission portion 18 is thinner than the base portion 19. For example, when viewed with the direction perpendicular to the side surface 191 as the line of sight, the maximum width of the base portion 19 in the direction perpendicular to the axis 105 of the emission member 10 is preferably 40 times or more, more preferably 50 times or more, the maximum width of the emission portion 18 in the direction perpendicular to the axis 105 of the emission member 10. When viewed with the direction perpendicular to the side surface 191 as the line of sight, the minimum width of the base portion 19 in the direction perpendicular to the axis 105 of the emission member 10 is preferably 10 times or more, more preferably 20 times or more, the maximum width of the emission portion 18 in the direction perpendicular to the axis 105 of the emission member 10.

[0041] From the viewpoint of work function, the emission member 10 contains MB ６ crystals. M is at least one of La and Ce. From the viewpoint of increasing the current value due to emitted charged particles, M is preferably La. 90% or more of the total volume of the emission member 10 is preferably composed of MB ６ crystals.

[0042] However, the constituent material of the emission member 10 is not limited to MB ６ crystals. The emission member 10 may contain one or more selected from the group consisting of tungsten, iridium, and lanthanoids. Examples of lanthanoids include lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, and lutetium. The emission member 10 may contain, as a constituent material, at least any one of tungsten, borides containing lanthanoids, CeB ６ , HfC, and a compound containing iridium and a lanthanoid. In particular, the emission member 10 may contain, as a constituent material, at least any one of a single crystal of tungsten, a single crystal of LaB ６ , a single crystal of CeB ６ , a single crystal of HfC, an IrCe compound, and an IrLa compound. As the IrCe compound, Ir ２ Ce, Ir ３ Ce, Ir ７ Ce ２ , Ir５ Examples include Ce. The constituent material of the discharge member 10 may be used alone or in combination of two or more materials. Preferably, the melting point of the discharge member 10 is 2000°C or higher.

[0043] The release member 10 is MB ６ If it contains crystals, the shaft 105 of the release member 10 and MB ６ It is preferable that the <100> direction of the crystal is approximately parallel to the axis 105 of the discharge member 10 and MB ６ The angle between the crystal and the <100> direction is preferably 5° or less, and more preferably 3° or less. This allows the work function at the emission surface of charged particles to be lowered.

[0044] Figure 5 is a magnified view showing the structure of the tip 100 and the vicinity of the tip 100 of the emission member 10. The radius of curvature of the tip 100 of the emission member 10 is not particularly limited, but from the viewpoint of the stability of the emitted charged particle beam, it is preferably 20 nm or more, and more preferably 30 nm or more. The stability of the emitted charged particle beam includes the stability of the obtained current and the stability of the electron beam pattern. Furthermore, from the viewpoint of reducing the beam diameter of the emitted charged particles, the radius of curvature of the tip 100 of the emission member 10 is preferably 500 nm or less, more preferably 200 nm or less, and even more preferably 60 nm or less. Note that the radius of curvature of the tip 100 refers to the radius of the smallest circle 107 that can be drawn superimposed on the tip 100 in the contour line 109 confirmed by the electron microscope image, as illustrated in Figure 5 and Figure 6 described later.

[0045] Figure 6 is an enlarged view showing the structure of the tip 100 and the vicinity of the tip 100 of the discharge member 10 according to a modified example. Facets may be formed on the tip 100 of the discharge member 10. The discharge member 10 may have a first plane 101 at its tip 100 that is approximately perpendicular to the axis 105. Specifically, the discharge member 10 may have a first plane 101 at its tip 100 whose angle with the axis 105 of the discharge member 10 is 85° or more and 90° or less. ６ If it contains crystals, the first plane 101 is MB ６It is preferable that the plane is parallel to the (100) plane of the crystal. The first plane 101 can be an emission surface that emits charged particles. By having the first plane 101 at the tip 100, the work function of the emission surface can be lowered.

[0046] The work function of the emission surface at the tip 100 is preferably 5 eV or less, and more preferably 3 eV or less.

[0047] Figure 7 is a diagram illustrating the distance d. In the example in Figure 7, the contour line 109 corresponds to the contour line of the emission member 10 when viewed with the line of sight perpendicular to the side surface 191. From the viewpoint of further reducing the influence of the base portion 19 on electric field concentration at the tip 100, and from the viewpoint of improving the manufacturing efficiency of the emission member 10, the distance d is preferably 15 μm or more, and more preferably 20 μm or more. The distance d is a straight line L when viewed from a direction perpendicular to the side surface 191. １ This is the distance between the tip 100 and the discharge member 10 in a direction parallel to the axis 105. １ Point P １ and point P ２ It is a straight line passing through point P. １ Point P is the point furthest from the tip 100 in the portion of the contour line 109 of the discharge member 10 that corresponds to the slope 193, when viewed with the line of sight perpendicular to the side surface 191. ２ This is the point closest to the tip 100 among the portion of the contour line 109 of the discharge member 10 that corresponds to the slope 193, when viewed with the line of sight perpendicular to the side surface 191. The width of the slope 193, i.e., point P １ and point P ２ The distance from point P is preferably 300 μm or more, and more preferably 400 μm or more. １ and point P ２ The distance to the object is preferably 700 μm or less, and more preferably 600 μm or less.

[0048] An example of a manufacturing method for the emission member 10 and the emitter 50 will be described below.

[0049] A columnar crystal is prepared as the constituent material for the discharge member 10. Next, a bonding material is applied to a part of the columnar crystal, and the cup 21 is heated and pressed onto it, thereby covering a part of the columnar crystal with the cup 21. Then, the first terminal 41, which penetrates the insulating member 40, and one side of the cup 21 are connected with a conductive member 30. In addition, the second terminal 42, which penetrates the insulating member 40, and the opposite side of the cup 21 are connected with another conductive member 30. In this way, the cup 21 and the columnar crystal are fixed to the member formed by the first terminal 41 and the second terminal 42 penetrating the insulating member 40.

[0050] Next, the portion of the columnar crystal exposed from the cup 21 is processed with a focused ion beam (FIB) to form the emission portion 18, thereby obtaining the emitter 50 according to this embodiment. In other words, the emission portion 18 and the base portion 19 of the emission member 10 are formed from a single columnar crystal.

[0051] The manufacturing methods for the emission member 10 and the emitter 50 are not limited to the examples described above. The emission portion 18 and the base portion 19 may be formed by removing a portion of the crystalline material by a method other than FIB processing, or the emission member 10 may be manufactured by joining the emission portion 18 to the base portion 19.

[0052] Figure 8 is a diagram illustrating the configuration of the electron gun 60 according to this embodiment. The electron gun 60 according to this embodiment includes an emitter 50 according to this embodiment. In the example in Figure 8, the electron gun 60 further includes an extraction electrode 62 facing the emitter 50. The electron gun 60 may be used in combination with power supplies 64 and 65. However, the electron gun 60 does not have to include these power supplies.

[0053] The extraction electrode 62 can be used to provide an electric field for emitting electrons from the emission member 10. The extraction electrode 62 may have a through hole 620 through which electrons emitted from the emission member 10 pass. When electrons are emitted, the extraction electrode 62 may have a positive potential relative to the first terminal 41 and the second terminal 42. A positive voltage V is applied to the extraction electrode 62 with the potential of the first terminal 41 as the reference. ｅｘThe power supply 64 may be connected to the extraction electrode 62 to apply a voltage. The voltage from the power supply 65 does not need to be applied when electrons are emitted. That is, the first terminal 41 and the second terminal 42 may be at the same potential when electrons are emitted.

[0054] The power supply 65 is used to heat the discharge member 10 during the flashing process described above. The power supply 65 can be connected to the first terminal 41 and the second terminal 42 so that current flows from the power supply 65 to the conductive member 30. While current is flowing through the conductive member 30, the first terminal 41 has a positive potential relative to the second terminal 42.

[0055] The electron gun 60 according to this embodiment may further include an accelerating electrode (not shown) facing the extraction electrode 62 at a position opposite to the emitter 50 with respect to the extraction electrode 62. In this case, the extraction electrode 62 is positioned between the emitter 50 and the accelerating electrode. The accelerating electrode can be used to accelerate electrons emitted from the emission member 10. The accelerating electrode may have a through hole through which electrons emitted from the emission member 10 pass. When electrons are emitted, the accelerating electrode may have a positive potential with respect to the potential of the extraction electrode 62.

[0056] A power supply is connected to the accelerating electrode to apply a voltage to it, and a positive voltage can be output to the accelerating electrode with the potential of the extraction electrode 62 as a reference.

[0057] The electron gun 60 according to this embodiment can be used in an electron beam apparatus. The electron beam apparatus may be equipped with the electron gun according to this embodiment. Examples of electron beam apparatuses include X-ray generators, electron microscopes, semiconductor manufacturing equipment, analytical equipment (inspection equipment: e.g., electron probe microanalyzers), processing equipment (e.g., electron beam deposition equipment), etc.

[0058] Next, the operation and effects of this embodiment will be described. According to this embodiment, the side surface 191 and the end surface 192 of the base portion 19 are connected via a slanted surface 193 that is oblique to both the side surface 191 and the end surface 192. This makes it easier for electric field concentration to occur at the tip 100 of the emitter 50, thereby reducing the extracted voltage.

[0059] This embodiment will be described in detail below with reference to the examples provided. However, this embodiment is not limited in any way to the examples described.

[0060] <Example> LaB ６ By FIB processing a single crystal, an emission member having the shape shown in Figures 3 and 4 was prepared. The axis of the emission member was LaB ６ The crystal was aligned parallel to the <100> direction. α was 103°, β was 153°, and γ was 130°. The distance d was 50 μm. The angle between the side surface and the axis of the emission member was 0°. The tip radius of curvature was 90 nm. The length of the emission section was 140 μm. When viewed with the line of sight perpendicular to the side surface of the base, the maximum width of the base in the direction perpendicular to the axis of the emission member was 50 times or more the maximum width of the emission section in the direction perpendicular to the axis of the emission member. When viewed with the line of sight perpendicular to the side surface of the base, the minimum width of the base in the direction perpendicular to the axis of the emission member was 20 times or more the maximum width of the emission section in the direction perpendicular to the axis of the emission member. An emitter equipped with the prepared emission member was prepared, and electron emission was initiated.

[0061] <Comparative example> LaB ６ A release member having the shape shown in Figure 9 was prepared by FIB processing a single crystal. That is, the base part was a rectangular parallelepiped and did not have a slope connecting the side and end faces. The axis of the release member was LaB ６ The crystal was aligned parallel to the <100> direction. The tip radius of curvature was 100 nm. When viewed with the line of sight perpendicular to the side surface of the base, the width of the base in the direction perpendicular to the axis of the emission member was more than 50 times the maximum width of the emission member in the direction perpendicular to the axis of the emission member. An emitter equipped with the prepared emission member was prepared and electron emission was initiated.

[0062] Figure 10 shows the relationship between the extracted voltage and total current measured using the emitters of the example and comparative example. As shown in Figure 10, the extracted voltage was reduced in the example compared to the comparative example.

[0063] In the comparative example, the electric field tended to concentrate at the sharp edge where the side surface and end surface intersected, which is thought to have negatively affected the concentration of the electric field at the tip of the discharge member. In contrast, in the embodiment, the electric field tended to concentrate at the tip of the discharge member.

[0064] The embodiments and examples of the present invention have been described above with reference to the drawings, but these are illustrative examples of the present invention, and various other configurations can be adopted. For example, the execution order of the steps performed in the embodiments is not limited to the order in which they are described. In the embodiments, the order of the steps can be changed to the extent that it does not impede the content. Furthermore, the embodiments described above can be combined to the extent that their content is not contradictory.

[0065] This application claims priority based on Japanese Patent Application No. 2025-037686, filed on 10 March 2025, and incorporates all of its disclosures herein.

[0066] 10 Discharge member 18 Discharge section 19 Base section 21 Cup 30 Conductive member 40 Insulating member 41 First terminal 42 Second terminal 50 Emitter 60 Electron gun 62 Lead electrode 64 Power supply 65 Power supply 100 Tip 101 First plane 105 Shaft 191 Side surface 192 End face 193 Inclined surface 620 Through hole

Claims

1. An emitter comprising a discharge member having a tip for emitting charged particles, wherein the discharge member comprises a base portion having a side surface and an end surface, and a discharge portion protruding from the end surface of the base portion and emitting charged particles from the tip, wherein the side surface and the end surface are connected via an inclined surface that is oblique to both the side surface and the end surface.

2. An emitter according to claim 1, wherein the angle between the side surface and the inclined surface is 135° or more and 165° or less.

3. An emitter according to claim 1 or 2, wherein the side surface and the end surface are not directly connected.

4. An emitter according to claim 1 or 2, wherein the angle between the side surface and the axis of the emission member is 3° or less.

5. An emitter according to claim 1 or 2, wherein the angle between the end face and the side surface is 75° or more and 105° or less.

6. An emitter according to claim 1 or 2, wherein the inclined surface is a curved surface.

7. An emitter according to claim 1 or 2, wherein, when viewed with the line of sight perpendicular to the side surface, the distance in a direction parallel to the axis of the emitter between the tip and the point closest to the tip in the portion of the contour line of the emitter corresponding to the slope is 15 μm or more.

8. An emitter according to claim 1 or 2, wherein the base portion is an emitter having four sides.

9. An emitter according to claim 1 or 2, wherein, when viewed with the direction perpendicular to the side surface as the line of sight, the maximum width of the base portion in the direction perpendicular to the axis of the emission member is 50 times or more the maximum width of the emission portion in the direction perpendicular to the axis of the emission member.

10. An emitter according to claim 1 or 2, wherein the radius of curvature of the tip is 20 nm or more and 500 nm or less.

11. In the emitter according to claim 1 or 2, the emission member is MB ６ An emitter containing a crystal, where M is at least one of La and Ce.

12. An emitter according to claim 11, wherein the angle between the axis of the emission member and the <100> direction of the crystal is 5° or less.

13. An emitter according to claim 1 or 2, wherein the emitter is an electron emitter.

14. An emitter according to claim 1 or 2, wherein the emitter is a cold cathode.

15. An electron gun comprising the emitter according to claim 1 or 2.

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