Charged particle energy analysis device

Abstract

The charged particle energy analysis device comprises a deflection cavity, an inlet of the deflection cavity is connected with an incident channel, and an outlet of the deflection cavity is connected with an emergent channel; an incident diaphragm and a front lens are sequentially arranged in the incident channel along the moving direction of the charged particles; a deflection magnetic field and a built-in lens are arranged in the deflection cavity; due to the coupling effect of the deflection magnetic field and the built-in lens, the charged particles entering the deflection cavity move to generate deflection; and in the emergent channel, an emergent diaphragm and a detector are sequentially arranged along the moving direction of the charged particles, so that space imaging of the charged particles is realized. The device designed by the invention not only can obtain the effect of deflection focusing of the charged particle beam, but also can meet the requirements of miniaturization and high precision of the device.

Description

Technical Field

[0001] The present invention relates to the technical field of electron energy analysis, and in particular to a charged particle energy analysis device. Background Art

[0002] Electron Energy Analyzer (EEA) is a key instrument for measuring the distribution of electron kinetic energy or binding energy. It is widely used in fields such as surface science (such as XPS, UPS), electron spectroscopy and plasma diagnostics. Common types of electron energy analyzers include hemispherical analyzers, cylindrical mirror analyzers, deceleration field analyzers, time-of-flight analyzers, parallel plate analyzers, magnetic bottle analyzers, multi-channel plate energy analyzers, etc. Among them, the electrons of the hemispherical analyzer pass through the electrostatic field (radial electric field) between two concentric hemispheres, and only electrons that meet a specific kinetic energy / charge ratio can be deflected through the exit slit; it has high resolution, but a complex structure. For example, the electrostatic hemispherical electron energy analyzer disclosed in US005185524A obtains a radial electric field through an electrostatic hemisphere as energy resolution and focusing, which has the disadvantages of high cost and large size. The electron energy loss spectrometer disclosed in US2022 / 0148849A1 uses a magnetic field for 90° offset. After completing the basic separation, the spherical aberration is large, requiring the back-end to correct the spherical aberration and amplify the separation effect, which will increase the size and cost of the device.

[0003] Therefore, in view of the defects of existing energy analysis devices, there is an urgent need for an energy analysis device with a compact structure, high analysis accuracy and lower cost. Summary of the Invention

[0004] In order to address the deficiencies in the prior art, this application proposes a charged particle energy analysis device that couples an electrostatic multipole lens with a deflection magnetic field to achieve the effect of deflecting and focusing a charged particle beam, while also taking into account the requirements of miniaturization and high precision of the device.

[0005] The technical solutions adopted in the present invention are as follows:

[0006] A charged particle energy analysis device, comprising:

[0007] An incident channel, in which an incident aperture and a front lens are sequentially arranged along the moving direction of the charged particles;

[0008] a deflection cavity connected to the incident channel, wherein a deflection magnetic field is configured in the deflection cavity, and a built-in lens is provided in the deflection cavity; spatial imaging is achieved by coupling the deflection magnetic field and the built-in lens;

[0009] An exit channel communicated with the deflection cavity, wherein an exit aperture and a detector are sequentially arranged in the exit channel along the moving direction of the charged particles;

[0010] The incident channel, the exit channel and the deflection cavity are all kept in vacuum and grounded.

[0011] Furthermore, the interior of the deflection cavity is hemispherical, and charged particles entering the deflection cavity from the deflection cavity entrance will turn under the combined action of the deflection magnetic field and the built-in lens, and then leave from the deflection cavity exit.

[0012] Furthermore, the front lens adopts an electrostatic multipole lens or a magnetic multipole lens for compensation calibration.

[0013] Furthermore, the built-in lens adopts an electrostatic multipole lens.

[0014] Furthermore, an external device is provided before the incident channel, and the charged particle beam is accelerated or decelerated by the external device, so that charged particles of different energies pass through the exit aperture and are recorded by the detector.

[0015] Furthermore, two electromagnets are symmetrically arranged in the deflection cavity, and a deflection magnetic field is generated by the two electromagnets, and the magnetic field strength of the deflection magnetic field is adjustable.

[0016] Furthermore, by adjusting the magnetic field strength, charged particles with different energies in the deflection cavity are separated and ejected.

[0017] Furthermore, an electric lens or a magnetic lens is provided before the entrance of the incident channel to focus and adjust the incoming charged particle beam.

[0018] Beneficial effects of the present invention:

[0019] 1. The present application designs a charged particle energy analysis device, in which the deflection magnetic field in the deflection cavity plays the role of high-precision energy spatial distribution separation. Through the electromagnetic coupling structure in the 180° rotation path, the built-in electrostatic multipole lens is embedded in the deflection magnetic field to obtain a new charged particle energy analysis device, which achieves the effect of charged particle beam deflection and focusing, thereby improving the high precision of detection.

[0020] 2. Compared with the same type of device in the prior art that adds a rear end spherical aberration elimination component, this device does not need to add a rear end spherical aberration elimination component, the vacuum cavity is reduced, and the device is miniaturized.

[0021] 3. This device uses the principle that charged particles of different energies have different turning radii in the same magnetic field to separate particle beams of different energies, ultimately achieving energy resolution of mixed charged particles of different energies.

[0022] 4. This device can be applied to XPS and PEEM and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1A schematic diagram of a charged particle energy analysis device structure.

[0024] Figure 2 A resolved image detected by the detector of the present application.

[0025] Figure 3 A simulated resolved image without post-processing of the electron energy loss spectrometer disclosed in prior art US2022 / 0148849 A1.

[0026] In the figure, 101, charged particle beam, 102, entrance aperture, 103, pre-lens, 104, built-in lens, 105, deflection magnetic field, 106, exit aperture, 107, detector, 108, entrance channel, 109, exit channel, 110, deflection cavity. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical scheme and advantages of the present application more clear, the present application is further described in detail below in combination with the drawings and examples. It should be understood that the specific examples described herein are only used to explain the present application and do not limit the present application.

[0028] In combination with the drawings Figure 1 The present application proposes a charged particle energy analysis device, which obtains the effect of deflection and focusing of the charged particle beam by coupling the lens group with the semi-circular magnetic field. At the same time, different energy charged particles are separated by using the principle that the turning radius of different energy charged particles in the same magnetic field is different, and finally the energy resolution of mixed different energy charged particles is achieved. The specific structure of the device is as follows:

[0029] A charged particle energy analysis device, comprising: an entrance channel 108, an exit channel 109, a deflection cavity 110, a pre-lens 103, a built-in lens 104, a deflection magnetic field 105, an aperture, and a detector 107. The installation of each component is as follows:

[0030] One end of the entrance channel 108 is connected with the entrance of the deflection cavity 110; in the entrance channel 108, an entrance aperture 102 and a pre-lens 103 are sequentially arranged along the direction of motion of the charged particles, and the pre-lens 103 plays a compensation and calibration function.

[0031] The deflection cavity 110 is in the shape of a hemisphere inside, and the deflection cavity 110 is configured with a deflection magnetic field 105; a built-in lens 104 is arranged at the middle position of the deflection magnetic field 105; the charged particles entering the deflection cavity 110 from the entrance of the deflection cavity 110 will make a 180° turn under the joint action of the magnetic field and the lens and then exit from the outlet of the deflection cavity 110.

[0032] One end of the exit channel 109 is connected to the exit of the deflection cavity 110 ; in the exit channel 109 , an exit aperture 106 and a detector 107 are sequentially arranged along the moving direction of the charged particles.

[0033] More specifically, the front lens 103 adopts an electrostatic multipole lens or a magnetic multipole lens, and specifically an electrostatic dipole, a quadrupole, a magnetic octupole, etc. can be selected.

[0034] More specifically, the built-in lens 104 adopts an electrostatic multipole lens, and specifically an electrostatic dipole, a quadrupole, an electrostatic octupole, etc. can be selected.

[0035] More specifically, an external device can be added before the incident channel 108 to accelerate or decelerate the charged particle beam 101. By using the external device to accelerate or decelerate the charged particle beam 101 as a whole while keeping other components unchanged, charged particles of different energies can pass through the exit aperture 106 smoothly, and the detector 107 records them. The charged particle beam can distinguish the energy and number of charged particles of different energies in 101, and obtain the following information: Figure 2 The resolved image is shown.

[0036] More specifically, in order to analyze charged particles of different energies in the charged particle beam 101, the front lens 103, the deflection magnetic field 105, and the built-in lens 104 of the device can be adjusted so that charged particle beams 101 of different energies pass through the exit aperture 106 separately and are recorded by the detector 107, so as to distinguish the energy and quantity of charged particles of different energies in the charged particle beam 101, and obtain the following information: Figure 2 The resolved image is shown.

[0037] The specific adjustment principles are as follows:

[0038] For charged particles with too high energy, since the turning radius of high-energy charged particles in the deflection cavity 110 is too large, it is necessary to adjust the front lens 103, the deflection magnetic field 105, and the built-in lens 104. By increasing the strength, the restraint force on the charged particle beam can be stronger and the turning radius can be smaller, so that high-energy charged particles can pass through the exit aperture 106 and be recorded by the detector 107.

[0039] For charged particles with too low energy, since the turning radius of low-energy charged particles in the deflection cavity 110 is too small, it is necessary to adjust the front lens 103, the deflection magnetic field 105, and the built-in lens 104. By reducing the intensity, the restraint force on the charged particle beam can be weaker and the turning radius can be larger, so that the low-energy charged particles can pass through the exit aperture 106 and be recorded by the detector 107.

[0040] More specifically, the incident channel 108 , the exit channel 109 , and the deflection cavity 110 all need to maintain a vacuum environment and be grounded.

[0041] More specifically, the deflection magnetic field 105 is provided by two electromagnets, which are symmetrically arranged on two sides of the deflection cavity 110, that is, the two electromagnets sandwich the deflection cavity 110 and provide the deflection cavity 110 with the same magnetic field as shown in FIG. Figure 1 A uniform magnetic field perpendicular to the plane. The magnetic field strength in the deflection field 105 is controlled by the coil current. Charged particles in the magnetic field are subject to the Lorentz force, causing them to move in a circular motion. Charged particles of different energies have different motion radii. The design controls the range of the magnetic field, allowing charged particles of different energies to separate and be ejected when they leave the magnetic field after only half of their movement.

[0042] More specifically, before the charged particle beam 101 enters the incident channel 108 , it can be focused and adjusted by an axisymmetric electric lens or magnetic lens.

[0043] The following is a detailed introduction to the working process of this device:

[0044] The focused charged particle beam 101 enters the device and is focused at the entrance aperture 102. After being screened by the entrance aperture 102, the charged particle beam 101 is sorted by the front lens 103 and then enters the deflection magnetic field 105. Under the joint action of the deflection magnetic field 105 and the built-in lens 104, it makes a 180° turn and is focused at the exit aperture 106. At this time, the charged particle beam 101 with appropriate energy just passes through the microhole of the exit aperture 106. At the same time, charged particles with too high or too low energy are blocked by the exit aperture 106 because the turning radius is too large or too small. The charged particle beam 101 with appropriate energy that passes through the exit aperture 106 is finally incident on the detector 107 and is detected, and the image is obtained as follows. Figure 2 The resolved image is shown.

[0045] Attachment Figure 2 What is shown is a simulated image of the resolution of particles of different energies that can be captured by the detector end 107 of the present invention. Figure 3 This is a simulated image of the analyzer outlet of the electron energy loss spectrometer disclosed in US2022 / 0148849 A1. By comparison, it can be seen that Figure 2 The electron beam separation effects of 39eV, 40eV and 41eV are respectively; Figure 2 It can be seen that the spacing is about 3.5mm for every increase of 1eV, and the resolution is obvious, which is high-precision resolution.

[0046] The above embodiments are intended only to illustrate the design concepts and features of the present invention. Their purpose is to enable those skilled in the art to understand the contents of the present invention and implement them accordingly. The scope of protection of the present invention is not limited to the above embodiments. Therefore, any equivalent changes or modifications made based on the principles and design concepts disclosed in the present invention are within the scope of protection of the present invention.

Claims

1. A charged particle energy analysis device, characterized in that: include: An incident channel (108), wherein an incident aperture (102) and a front lens (103) are sequentially arranged in the incident channel (108) along the moving direction of the charged particles; A deflection cavity (110) communicated with the incident channel (108), wherein a deflection magnetic field (105) is disposed in the deflection cavity (110), and a built-in lens (104) is provided in the deflection cavity (110); spatial imaging is achieved by coupling the deflection magnetic field (105) and the built-in lens (104); An exit channel (109) communicated with the deflection cavity (110), wherein an exit aperture (106) and a detector (107) are sequentially arranged in the exit channel (109) along the moving direction of the charged particles; The incident channel (108), the exit channel (109), and the deflection cavity 110 are all kept in vacuum and grounded.

2. A charged particle energy analysis device according to claim 1, characterized in that: The interior of the deflection cavity (110) is hemispherical. Charged particles entering the deflection cavity (110) from the entrance of the deflection cavity (110) are turned under the combined action of the deflection magnetic field (105) and the built-in lens (104), and then leave from the exit of the deflection cavity (110).

3. The magnetic electrostatic coupled charged particle energy analysis device according to claim 1, characterized in that: The front lens (103) adopts an electrostatic multipole lens or a magnetic multipole lens for compensation calibration.

4. The magnetic electrostatic coupled charged particle energy analysis device according to claim 1, characterized in that: The built-in lens (104) is an electrostatic multipole lens.

5. The charged particle energy analysis device according to claim 1, characterized in that: An external device is provided before the incident channel (108), and the external device is used to accelerate or decelerate the charged particle beam (101), so that charged particles of different energies pass through the exit aperture (106) and are recorded by the detector (107).

6. The charged particle energy analysis device according to claim 1, characterized in that: Two electromagnets are symmetrically arranged in the deflection cavity (110), and a deflection magnetic field (105) is generated by the two electromagnets, and the magnetic field intensity of the deflection magnetic field (105) is adjustable.

7. The charged particle energy analysis device according to claim 6, characterized in that: By adjusting the magnetic field strength, charged particles with different energies in the deflection cavity (110) are separated and ejected.

8. The charged particle energy analysis device according to claim 1, characterized in that: An electric lens or a magnetic lens is arranged before the entrance of the incident channel (108) to focus and adjust the incoming charged particle beam.

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