An electronic source structure for boosting supply current and a method of manufacturing the same

Abstract

The present application relates to the technical field of vacuum micro-nano electron source, and more particularly to an electron source structure for increasing supply current and a preparation method thereof, which utilizes an insulating layer with uniform thickness to cover the surface of a P-type semiconductor protruding structure in series with an emitter, a control electrode on the outer surface of the covering insulating layer is at a high potential relative to the P-type semiconductor, a large-area carrier depletion layer is formed on the side surface of the protruding structure, and heat-generated electrons in the carrier depletion layer are used to supply field emission current to the emitter, so as to increase the heat-generated current supplied to the emitter per unit substrate area, increase the emission current intensity and current density, and effectively solve the problems of small supply current density, limited emission current intensity and current density in the prior art electron source based on an integrated control electrode of a P-type semiconductor substrate.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of vacuum micro-nano electron sources, and more particularly to an electron source structure for improving supply current and a preparation method thereof. BACKGROUND

[0002] High-energy-resolution mass spectrometers, micro-thruster charge neutralizers, electrodynamic cables, and ultra-high-vacuum ionization gauges require electron sources with high current density, high current stability, and long working life. Field emission electron sources prepared on P-type semiconductor substrates have high current stability and can be used as high-quality electron sources in the above-mentioned fields. However, since electrons are minority carriers in P-type semiconductors, field emission electron sources prepared on P-type semiconductor substrates have saturation emission characteristics, and the emission current intensity and current density need to be improved.

[0003] In the conventional integrated control electrode field emission electron source based on a P-type semiconductor substrate, the insulating layer and the control electrode are both planar thin layers that are tiled on the substrate. The control electrode is at a high potential relative to the substrate, inducing the formation of a carrier depletion layer on the surface of the substrate. The thermally generated electrons in the depletion layer supply the field emission current. The depletion layer is a quasi-two-dimensional thin layer structure, and the thermally generated current is proportional to the area of the depletion thin layer. For a specific depletion thin layer area, the amount of current supply is constant, and increasing the number of emitters does not help to improve the emission current intensity and current density. Tightly packing the emitters in a small area of the depletion thin layer will result in uneven distribution of supply electrons and inconsistent emission current, which is not conducive to the improvement of the total emission current intensity and current density. Meanwhile, increasing the area of the depletion thin layer and the distance between adjacent emitters helps to improve the emission current but is not conducive to the improvement of the emission current density, and leads to an increase in the size of the device and a decrease in the manufacturing yield.

[0004] Therefore, in the conventional integrated planar control electrode electron source based on a P-type semiconductor substrate, the control electrode and the carrier depletion region induced by the control electrode are planar thin layer structures, and there is a problem of small supply current density and limited emission current intensity and current density in the integrated control electrode electron source based on a P-type semiconductor substrate. SUMMARY

[0005] The present application aims to overcome the deficiencies of small supply current per unit substrate area and limited emission current intensity and current density in the prior art, and provides an electron source structure for improving supply current and a preparation method thereof.

[0006] To solve the above technical problems, the technical solution adopted by the present application is as follows:

[0007] An electron source structure for supplying current, comprising a substrate, a plurality of protruding structures, a plurality of emitters, an insulating layer and a control electrode; the substrate and the protruding structures are both P-type doped semiconductor materials; the substrate, the protruding structures and the emitters are stacked in order from bottom to top; the side surface area of the protruding structures is greater than one-tenth of the square of the horizontal spacing of the adjacent emitters; the insulating layer has a uniform thickness and is attached to the surface of the protruding structures and the substrate, and the control electrode covers the outer surface of the insulating layer; the insulating layer and the control electrode are provided with a plurality of micro-holes with spatially overlapping areas, and the emitters are accommodated in the micro-holes; the control electrode is at a high potential relative to the protruding structures and the substrate, inducing the formation of an electron inversion layer and a carrier depletion layer on the P-type semiconductor surface covered by the control electrode.

[0008] An electron source structure for supplying current, comprising a substrate, a plurality of protruding structures, a plurality of emitters, an insulating layer and a control electrode; the substrate and the protruding structures are both P-type doped semiconductor materials; the substrate, the protruding structures and the emitters are stacked in order from bottom to top; the side surface area of the protruding structures is greater than one-tenth of the square of the horizontal spacing of the adjacent emitters; the insulating layer has a uniform thickness and is attached to the surface of the protruding structures and the substrate, and the control electrode covers the outer surface of the insulating layer; the insulating layer and the control electrode are provided with a plurality of micro-holes with spatially overlapping areas, and the emitters are accommodated in the micro-holes; the control electrode is at a high potential relative to the protruding structures and the substrate, inducing the formation of an electron inversion layer and a carrier depletion layer on the P-type semiconductor surface covered by the control electrode.

[0009] It should be noted that the device structure with the emitter in series with the protruding structure has been applied to the integrated control electrode electron source, but the device structure and function thereof are quite different from those of the present application. The existing structure adopts the emitter and a large height-diameter ratio N-type doped semiconductor nanocolumn (diameter of 100 nm, height > 10 μm) in series integration, the insulating layer completely fills the horizontal gap between the emitters and the protruding structure, and the control electrode is a planar electrode. This structure uses the nanocolumn as a current limiting element to limit the current transported from the N-type semiconductor substrate to the emitter, thereby weakening the current of the emitter with excellent emission characteristics in the device and improving the emission current uniformity. In the present application, a large-area carrier depletion layer is required to be formed on the side surface of the P-type semiconductor protruding structure, and the characteristic size of the cross section of the protruding structure is generally microns, thereby improving the heat generation current supplied to the emitter. At the same time, the present application uses the insulating layer with uniform thickness to adhere to and cover the surface of the P-type semiconductor protruding structure in series with the emitter, and the control electrode covering the surface of the insulating layer is placed at a high potential relative to the protruding structure and the substrate, thereby inducing the formation of a carrier depletion layer on the surfaces of the two, and supplying heat generation current to the emitter. If the existing device structure is used, and the N-type doped semiconductor therein is replaced by a P-type doped semiconductor, it is difficult to induce the formation of a depletion region and supply generation current due to the long distance from the control electrode to the middle and lower parts of the side surface of the protruding structure and the substrate. Even if a depletion region is formed, the electron concentration in the above surface electron inversion layer is much smaller than that on the upper part of the side surface of the protruding structure, forming a negative electron concentration gradient, which is not conducive to the diffusion and transport of electrons in the depletion layer to the emitter, and cannot achieve the improvement of the supply current intensity and current density.

[0010] Further, the protruding structure is a cylinder, a prism, a circular truncated pyramid, a prismatic truncated pyramid, or an irregular protruding shape with a height-diameter ratio greater than 5.

[0011] Further, the emitter is one or more of a micro-tip, a nanowire, a nanotube, a nanoparticle, and a two-dimensional film.

[0012] Further, the material constituting the substrate and the protruding structure is one or more of P-type doped elemental silicon, elemental germanium, gallium arsenide, gallium nitride, silicon carbide, indium phosphide, gallium oxide, zinc oxide, and diamond.

[0013] Further, the impurity concentration of the P-type semiconductor substrate and the protruding structure is higher than the intrinsic carrier concentration of the substrate material at room temperature and lower than 10 20 cm -3 .

[0014] Further, the material of the control electrode is one or more of gold, silver, aluminum, chromium, molybdenum, nickel, niobium, tantalum, graphite, heavily doped polysilicon, and lanthanum hexaboride.

[0015] The application also provides a preparation method of the electron source structure for supplying current, comprising the following steps:

[0016] S11. Preparing a plurality of the emitters on the substrate, depositing a sacrificial layer, and wrapping the emitters in the sacrificial layer;

[0017] S12. Spinning photoresist to define a photoresist pattern covering each of the emitters;

[0018] S13. Etching the sacrificial layer not covered by the photoresist, and removing the photoresist;

[0019] S14. Deep etching the material of the substrate not covered by the sacrificial layer in a direction perpendicular to the surface of the substrate to form the protruding structure under each of the emitters, and removing the sacrificial layer;

[0020] S15. Sequentially depositing the material of the insulating layer and the material of the control electrode;

[0021] S16. Spinning photoresist to cover the material of the control electrode, defining a photoresist pattern as the profile of the control electrode;

[0022] S17. Etching the photoresist to thin the photoresist until the control electrode protruding above the emitter is exposed, removing the control electrode not covered by the photoresist to form the micropore;

[0023] S18. Removing the photoresist, and removing the insulating layer by wet etching to form the micropore until the top end of the emitter is exposed.

[0024] Further, step S15 can be replaced by: sequentially depositing the material of the insulating layer and the material of the control electrode until the material of the control electrode completely fills the horizontal gap between the insulating layers covering adjacent protruding structures, using a surface planarization technique to make the upper surface of the control electrode planar and remove the material of the control electrode above the emitter to form the micropore; and step S17 is not required to etch the photoresist.

[0025] Further, a preparation method of the electron source structure for supplying current can be replaced by the following steps:

[0026] S21. Depositing a sacrificial layer on the substrate, spinning photoresist to define a photoresist pattern, etching the sacrificial layer not covered by the photoresist, and removing the photoresist;

[0027] S22. Deep etching the material of the substrate not covered by the sacrificial layer in a direction perpendicular to the substrate to form the protruding structure, and removing the sacrificial layer;

[0028] S23. Sequentially depositing the material of the insulating layer and the material of the control electrode;

[0029] S24. Spin coating photoresist, defining the pattern of the control electrode profile and the micropores above the protruding structure;

[0030] S25. Etching the control electrode and the insulating layer successively, which are not covered by photoresist, to form the micropores;

[0031] S26. Depositing the material of the emitter, preparing the emitter in the micropores, and simultaneously depositing the material of the emitter on photoresist;

[0032] S27. Removing photoresist, and the material of the emitter above it is also removed.

[0033] Further, step S23 can be replaced by: successively covering and depositing the material of the insulating layer and the material of the control electrode until the material of the control electrode completely fills and covers the horizontal gap between the insulating layers adjacent to the protruding structure, and using surface planarization technology to make the upper surface of the control electrode planar.

[0034] Compared with the prior art, the beneficial effects of the present application are:

[0035] The electronic source structure of the present application for increasing supply current uses the insulating layer with uniform thickness to adhere and cover the surface of the P-type semiconductor protruding structure in series with the emitter, the control electrode covering the outer surface of the insulating layer is at a high potential relative to the P-type semiconductor, a large area of carrier depletion layer is formed on the side surface of the protruding structure, and the heat generated electrons are used to supply field emission to the emitter, thereby increasing the heat generated current supplied to the emitter per unit substrate area, and improving the emission current intensity and current density, effectively solving the technical problems of small supply current density, limited emission current intensity and current density in the integrated control electrode electronic source based on the P-type semiconductor substrate in the prior art. BRIEF DESCRIPTION OF DRAWINGS

[0036] Figure 1 Structure diagram of the electronic source structure of the present application for increasing supply current with uniform thickness of control electrode in Example 1;

[0037] Figure 2 Structure diagram of the electronic source structure of the present application for increasing supply current with planar upper surface of control electrode in Example 2;

[0038] Figure 3 Structure diagram of the integrated control electrode electronic source structure in Comparative Example 1;

[0039] Figure 4 Structure diagram of the integrated control electrode electronic source structure in Comparative Example 2.

[0040] In the drawing: 1, emitter; 2, convex structure; 3, insulating layer; 4, control electrode; 5, substrate; 6, micropore. DETAILED DESCRIPTION

[0041] The application will be further described below in connection with the specific embodiments. In the drawings, only for exemplary illustration, the representation is only a schematic diagram, not a physical diagram, and cannot be understood as a limitation of the patent; in order to better illustrate the embodiments of the application, some components of the drawings will be omitted, enlarged or reduced, and do not represent the size of the actual product; for those skilled in the art, it is understandable that some well-known structures and their descriptions in the drawings can be omitted.

[0042] The same or similar reference numerals in the drawings of the embodiments of the application correspond to the same or similar components; in the description of the application, it should be understood that if the terms "upper", "lower", "left", "right" and the like indicate the orientation or positional relationship shown in the drawings, only for the convenience of describing the application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, therefore the positional relationship described in the drawings is only for exemplary illustration, and cannot be understood as a limitation of the patent, for those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0043] Embodiment one

[0044] As Figure 1 shown is a first embodiment of the electronic source structure for improving the supply current.

[0045] An electronic source structure for improving the supply current, comprising a substrate 5, a plurality of convex structures 2, a plurality of emitters 1, an insulating layer 3 and a control electrode 4; the substrate 5 and the convex structure 2 are both P-type doped semiconductor materials (in this embodiment, the P-type doped semiconductor material is boron-doped silicon, the impurity concentration is 10 15 cm -3); the substrate 5, the protruding structure 2 and the emitter 1 (in this embodiment, the emitter 1 is a silicon micro-tip with a horizontal interval of 10 μm) are stacked in sequence from bottom to top; the side surface area of the protruding structure 2 (in this embodiment, the protruding structure 2 is a micro-pillar with a diameter of 5 μm and a height of 50 μm) is greater than one-tenth of the square of the horizontal interval of the adjacent emitter 1; the insulating layer 3 (in this embodiment, the insulating layer 3 is silicon dioxide with a thickness of 1 μm) is attached to cover the surface of the protruding structure 2 and the substrate 5, and the control electrode 4 (in this embodiment, the control electrode 4 is chromium with a thickness of 200 nm) covers the outer surface of the insulating layer 3; the insulating layer 3 and the control electrode 4 are provided with a plurality of micro-holes 6 with spatial area overlap, and the emitter 1 is accommodated in the micro-hole 6; the control electrode 4 is at a high potential (in this embodiment, the potential difference is 100 V) relative to the substrate 5, so as to induce the surface of the P-type semiconductor covered by the control electrode 4 to form an electron inversion layer and a carrier depletion layer.

[0046] In this embodiment, as shown in Figure 1 , the control electrode 4, the insulating layer 3, the P-type semiconductor protruding structure 2 attached to the insulating layer 3 and the surface of the substrate 5 together form a metal-oxide-semiconductor (MOS) structure; the control electrode 4 is at a high potential relative to the substrate 5, so as to form a carrier depletion layer on the surface of the protruding structure 2 and the substrate 5, and the heat-generated electrons in the depletion layer are transported to the emitter 1 to supply field emission current. The heat-generated current is proportional to the volume of the depletion layer. According to the calculation of the ideal semiconductor device physical model, the thickness of the carrier depletion layer is about 0.86 μm, which is smaller than the radius of the protruding structure (2.5 μm), and the carrier depletion layer on the side surface of the protruding structure does not penetrate the protruding structure. Therefore, the depletion layer is a quasi-two-dimensional thin layer structure, and the depletion layer area at different positions can be used to compare the volume of the depletion layer, and then the generated current intensity supplied by the depletion layer can be compared. The top surface area of a single micro-pillar is 2.5×2.5×π=20 μm 2 , the side surface area is 5×π×50=785 μm 2 , and the surface area of the substrate 5 at the shortest distance to the micro-pillar is 10×10-20=80 μm 2 . It can be seen that the depletion layer on the side surface of the micro-pillar is the main source of generated current supply, the depletion layer is perpendicular to the substrate 5, and the horizontal area occupied by the depletion layer is small, which effectively improves the current supplied to the emitter 1 per unit area of the substrate 5, supplies sufficient electrons, and at the same time realizes the dense arrangement of the emitter 1, and provides high-intensity and high-density emission current. It effectively solves the technical problems of small current density, limited emission current intensity and current density in the existing technology of integrated control electrode 4 electron source based on P-type semiconductor substrate 5.

[0047] The above-mentioned electron source structure can be prepared by the following method:

[0048] S11. A plurality of silicon micro-tip emitters 1 with a pitch of 10 μm are prepared on a substrate 5, a 2 μm-thick silicon dioxide is deposited by chemical vapor deposition to wrap the silicon micro-tip in silicon dioxide;

[0049] S12. A photoresist is spin-coated to define a photoresist circular pattern with a diameter of 5 μm, and the silicon micro-tip is located within the photoresist pattern;

[0050] S13. The silicon dioxide not covered by the photoresist is etched, and the photoresist is removed;

[0051] S14. The substrate 5 material not covered by the silicon dioxide is etched along a direction perpendicular to the surface of the substrate 5 to a depth of 50 μm to form a protrusion structure 2 under each silicon micro-tip emitter 1, and the silicon dioxide is removed;

[0052] S15. A 1 μm-thick silicon dioxide insulation layer 3 is deposited by chemical vapor deposition, and a 200 nm-thick chromium is deposited by magnetron sputtering;

[0053] S16. A photoresist is spin-coated to cover the chromium, and a photoetching pattern is defined to be the profile of the chromium control electrode 4;

[0054] S17. The photoresist is thinned by etching until the chromium protruding above the silicon micro-tip is exposed, and the chromium not covered by the photoresist is removed to form a micro-hole 6;

[0055] S18. The photoresist is removed, and the silicon dioxide is removed by wet etching to form the micro-hole 6 until the top end of the silicon micro-tip emitter 1 is exposed.

[0056] Embodiment Two

[0057] As shown in FIG. 2, a second embodiment of the electron source structure of the present application is shown. Figure 2

[0058] The embodiment is similar to the first embodiment, except that the control electrode 4 completely fills the horizontal gap between the insulation layers 3 covering the protrusion structures 2. In the preparation step S15, after the insulation layer 3 is deposited along the surface of the substrate 5 and the protrusion structure 2, the control electrode 4 (metallic chromium) is deposited by magnetron sputtering until the horizontal gap between the insulation layers 3 covering the adjacent protrusion structures 2 is completely filled, the surface of the chromium is planarized by chemical mechanical polishing, and the chromium above the emitter 1 is removed, which is beneficial to the reliability of the electron source structure in the subsequent process steps and in the working process of the device; in step S17, the photoresist does not need to be thinned. In the embodiment, the shortest distance from the control electrode 4 to the surface of the P-type semiconductor protrusion structure 2 and the substrate 5 is the same as in the first embodiment, which can induce a large-area carrier depletion layer on the side surface of the protrusion structure 2 to improve the heat generation current supplied to the emitter 1. ​

[0059] Comparative Example 1

[0060] like Figure 3 As shown, the integrated electrode electron source structure commonly used in the field is similar to that of Example 1, except that: the aspect ratio of the protruding structure 2 is 0, that is, the protruding structure 2 does not exist, and the field emission current of the emitter 1 is supplied by the thermally generated electrons in the planar thin layer of the carrier depletion region on the surface of the substrate 5. The current supplied to the emitter 1 per unit area of ​​the substrate 5 is small, and the field emission current intensity and current density are limited.

[0061] Comparative Example 2

[0062] like Figure 4 The structure of a concentrated electrode electron source shown is similar to that of Example 1, except that the thickness of the insulating layer 3 is uneven and completely fills the horizontal gap between the protruding structures 2. The distance between the control electrode 4 and the middle and lower part of the side of the protruding structure 2 and the substrate 5 is relatively far. The voltage of the control electrode 4 makes it difficult for the surface of the above-mentioned P-type semiconductor to reach a strong inversion state. The volume of the device depletion region is small, and it is difficult to fully supply field emission. Even if the surface of the above-mentioned P-type semiconductor reaches a strong inversion state, the electron concentration in its surface inversion layer is much lower than the electron concentration in the inversion layer on the upper part of the protruding structure 2. There is a negative electron concentration gradient, and it is difficult for electrons to effectively diffuse and transport to the emitter 1 to supply field emission. Therefore, the emission current and current density are limited.

[0063] Example 3

[0064] This embodiment is the third embodiment of an electron source structure for increasing supply current according to the present invention.

[0065] This embodiment is similar to the first or second embodiment, except that the protruding structure 2 is a cylinder, prism, truncated cone, truncated pyramid or irregular protrusion with a height-to-diameter ratio greater than 5. The emitter 1 is one or more of a micro-cone, a nanowire, a nanotube, a nanoparticle, and a two-dimensional film. The material constituting the substrate 5 and the protruding structure 2 is one or more of P-type doped elemental silicon, elemental germanium, gallium arsenide, gallium nitride, silicon carbide, indium phosphide, gallium oxide, zinc oxide, and diamond. The impurity concentration of the P-type semiconductor substrate 5 and the protruding structure 2 is higher than the intrinsic carrier concentration of the substrate 5 material at room temperature and is lower than 10 20 cm -3 The material of the control electrode 4 is one or an alloy of two or more materials selected from the group consisting of gold, silver, aluminum, chromium, molybdenum, nickel, niobium, tantalum, graphite, heavily doped polysilicon, and lanthanum hexaboride.

[0066] This embodiment can be prepared by the following method:

[0067] S21 deposits a sacrificial layer on the substrate 5, spin-coats a photoresist, defines a photoresist pattern, etches the sacrificial layer not covered by the photoresist, and removes the photoresist;

[0068] S22. Etching the material of the substrate not covered by the sacrificial layer in a direction perpendicular to the substrate to form the protruding structure 2, and removing the sacrificial layer;

[0069] S23. Depositing the material of the insulating layer 3 and the control electrode 4 successively;

[0070] S24. Spinning photoresist to define the pattern of the control electrode 4 profile and the micropore above the protruding structure 2;

[0071] S25. Etching the control electrode 4 and the insulating layer 3 successively to form the micropore 6, which is not covered by the photoresist;

[0072] S26. Depositing the material of the emitter 1 in the micropore to form the emitter 1, and simultaneously depositing the material of the emitter 1 on the photoresist;

[0073] S27. Removing the photoresist, and the material of the emitter 1 above the photoresist is removed as well.

[0074] In the above embodiment, the step S23 can be replaced by: depositing the material of the insulating layer 3 and the material of the control electrode 4 successively until the material of the control electrode 4 completely fills the horizontal gap between the insulating layers 3 covering the adjacent protruding structures 2, and using surface planarization technology to make the upper surface of the control electrode 4 planar.

[0075] In the specific contents of the above embodiment, any technically feasible combination of the technical features can be made, and for the sake of brevity, not all possible combinations of the above technical features are described, however, as long as the combination of the technical features does not exist, it should be considered as the scope of the present disclosure.

[0076] Obviously, the above-mentioned embodiments of the present application are only examples for clearly illustrating the present application, and are not intended to limit the implementation modes of the present application. Based on the above description, other different forms of changes or variations can be made by those skilled in the art. Here, it is not necessary and also impossible to exhaust all the implementation modes. Any modification, equivalent replacement and improvement, etc. made within the spirit and principle of the present application should be included in the protection scope of the claims of the present application.

Claims

1. An electron source structure for increasing supply current, characterized in that: The invention comprises a substrate (5), a plurality of protruding structures (2), a plurality of emitters (1), an insulating layer (3) and a control electrode (4); the substrate (5) and the protruding structures (2) are both made of P-type doped semiconductor materials; the substrate (5), the protruding structures (2) and the emitters (1) are stacked in sequence from bottom to top; the side surface area of ​​the protruding structures (2) is greater than one tenth of the square of the horizontal spacing between adjacent emitters (1); the insulating layer (3) has a uniform thickness and is laminated and covered along the surfaces of the protruding structures (2) and the substrate (5); the control electrode (4) covers the insulating layer (3) ) outer surface; the insulating layer (3) and the control electrode (4) are provided with a plurality of micropores (6) with spatially overlapping regions, and the emitter (1) is accommodated in the micropores (6); the control electrode (4) is at a high potential relative to the protruding structure (2) and the substrate (5), inducing the formation of an electron inversion layer and a carrier depletion layer on the surface of the protruding structure (2) and the substrate (5) covered by the control electrode (4); the carrier depletion layer is perpendicular to the substrate (5), and thermally generated electrons in the carrier depletion layer are transported to the emitter (1) to supply field emission current.

2. The electron source structure for increasing supply current according to claim 1, characterized in that: The protruding structure (2) is in the shape of a cylinder, a prism, a frustum, a pyramid or an irregular protrusion with a height-to-diameter ratio greater than 5.

3. The electron source structure for increasing supply current according to claim 1, wherein: The emitter (1) is one or more of a micro-cone, a nanowire, a nanotube, a nanoparticle, and a two-dimensional film.

4. The electron source structure for increasing supply current according to claim 1, wherein: The materials constituting the substrate (5) and the protruding structure (2) are one or more of P-type doped elemental silicon, elemental germanium, gallium arsenide, gallium nitride, silicon carbide, indium phosphide, gallium oxide, zinc oxide, and diamond.

5. The electron source structure for increasing supply current according to claim 1, wherein: The impurity concentration of the substrate (5) and the protruding structure (2) is higher than the intrinsic carrier concentration of the substrate (5) material at room temperature and is lower than 10 20 cm -3 .

6. The electron source structure for increasing supply current according to claim 1, characterized in that: The material of the control electrode (4) is one or an alloy composed of two or more materials selected from the group consisting of gold, silver, aluminum, chromium, molybdenum, nickel, niobium, tantalum, graphite, heavily doped polysilicon, and lanthanum hexaboride.

7. A method for preparing an electron source structure for improving supply current, for preparing the electron source structure for improving supply current according to any one of claims 1 to 6, characterized in that: The following steps are involved: S11. Preparing a plurality of emitters (1) on the substrate (5), depositing a sacrificial layer, and encapsulating the emitters (1) in the sacrificial layer; S12 spin-coating a photoresist, defining a photoresist pattern covering each of the emitters (1); S13 etching the sacrificial layer not covered by the photoresist to remove the photoresist; S14. Deeply etching the material of the substrate (5) not covered by the sacrificial layer in a direction perpendicular to the surface of the substrate (5) to form the protruding structure (2) below each of the emitters (1), and removing the sacrificial layer; S15. Sequentially covering and depositing the insulating layer (3) and the control electrode (4) material; S16 spin-coating a photoresist, the photoresist covering the material of the control electrode (4), defining a photolithographic pattern as the outline of the control electrode (4); S17. etching and thinning the photoresist to expose the control electrode (4) protruding above the emitter (1), and removing the control electrode (4) not covered by the photoresist to form the micropore (6); S18. Remove the photoresist, and remove the insulating layer (3) by wet etching to form the microhole (6) until the top of the emitter (1) is exposed.

8. A method for preparing an electron source structure for improving supply current, for preparing the electron source structure for improving supply current according to any one of claims 1 to 6, characterized in that: The following steps are involved: S21. Depositing a sacrificial layer on the substrate (5), spin-coating a photoresist, defining a photoresist pattern, etching the sacrificial layer not covered by the photoresist, and removing the photoresist; S22. Deeply etching the material of the substrate (5) not covered by the sacrificial layer in a direction perpendicular to the substrate (5) to form the protruding structure (2), and removing the sacrificial layer; S23 sequentially covering the insulating layer (3) and the control electrode (4) material is deposited; S24. Spin-coating a photoresist to define the contour of the control electrode (4) and the pattern of the micropores (6) located above the protruding structure (2); S25. Sequentially etching the control electrode (4) and the insulating layer (3) not covered by the photoresist to form the micropore (6); S26. depositing the material of the emitter (1), preparing the emitter (1) in the microhole (6), and simultaneously depositing the material of the emitter (1) on the photoresist; S27. Remove the photoresist, and also remove the material of the emitter (1) above it.

9. The method for preparing an electron source structure for improving supply current according to claim 7, characterized in that: Step S15 is replaced by: sequentially depositing the material of the insulating layer (3) and the material of the control electrode (4) until the material of the control electrode (4) completely fills the horizontal gap between the insulating layers (3) covering the adjacent protruding structures (2), using a surface flattening technique to make the upper surface of the control electrode (4) flat and removing the material of the control electrode (4) above the emitter (1) to form the micropore (6); and in step S17, there is no need to etch and thin the photoresist.

10. The method for preparing an electron source structure for improving supply current according to claim 8, characterized in that: Step S23 is replaced by: sequentially depositing the material of the insulating layer (3) and the material of the control electrode (4) until the material of the control electrode (4) completely fills the horizontal gap between the insulating layers (3) covering adjacent protrusion structures (2), and using surface flattening technology to make the upper surface of the control electrode (4) flat.

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