Self-constrained transverse extension ion optical lens device

Abstract

The invention discloses a self-constrained transverse extension ion optical lens device, and belongs to the technical field of cluster ion lens devices. The invention discloses a self-constrained transverse extension ion optical lens device which comprises a cuboid vacuum cavity and an ion lens device. The ion lens device comprises an entrance slit of an ion optical lens, an exit slit of the ion optical lens and an electrode group; the electrode group comprises a conical plate electrode group and a parallel plate electrode group; a crack at the head end of the conical plate electrode group forms an inlet slit of the ion optical lens, the tail end of the conical plate electrode group is connected with the head end of the parallel plate electrode group, and a crack at the tail end of the parallel plate electrode group forms an outlet slit of the ion optical lens; one side of the cuboid vacuum cavity is provided with a cluster beam generation device outlet, and the ion lens device is arranged in the cuboid vacuum cavity. Under the condition that the beam density in the prior art is kept unchanged, the cluster beam intensity entering and leaving the ion optical part is increased, and the cluster yield is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of cluster ion lens devices, and in particular to a self-constrained laterally extended ion optical lens device. Background Art

[0002] Existing ion optical lens devices use a circular stream of cluster ions entering through an inlet. After being focused by the ion optical lens, it enters the mass selector to screen and separate clusters of corresponding mass. Any axisymmetric electrode system can be considered an electrostatic field lens. A characteristic of electrostatic field lenses is that both focusing characteristics and phase difference are independent of the charge-to-mass ratio of the ions, considering only electrostatic effects.

[0003] Application number CN201410685726.3 provides a method and apparatus for tuning an ion lens system. All ion lens combination intervals through which ions can pass are obtained by applying voltage to a cylindrical metal to interfere with the ion path. The ion lens combination intervals include a combination of ion lens voltage values ​​and tuning interval values. Regression analysis is performed on each ion lens combination interval to obtain a regression coefficient for each ion lens combination interval. Based on the regression coefficient, the extreme value of each ion lens combination interval is calculated. The ion lens system is tuned according to the ion lens combination interval corresponding to the maximum extreme value. In the prior art, after a skimmer (ring-shaped skimmer) removes highly divergent cluster ions, the ions enter the entrance of the ion (optical) lens section and pass through an electrostatic lens system composed of multiple cylindrical electrodes to achieve focused control of the charged clusters, with their focal point at the exit of the mass selector. One way to increase cluster beam intensity is to increase the cluster beam density, and another way is to increase the cross-sectional area through which the beam passes. Due to the Coulomb force between charged ions, the beam density cannot be increased indefinitely. However, by proportionally enlarging the tuning device of the patented ion lens system to increase the cluster beam intensity, it is necessary to enlarge the entrance area of ​​the electrostatic lens group composed of multiple cylindrical electrodes by n. 2 times, the space volume needs to be enlarged by n 3 When the required cluster beam intensity is stronger, it cannot be achieved by proportionally amplifying the tuning device of the patented ion lens system.

[0004] Therefore, it becomes crucial to increase the cluster beam intensity entering and leaving the ion optical part while keeping the beam density unchanged in the existing technology. Summary of the Invention

[0005] The purpose of the present invention is to provide a self-constrained laterally extended ion optical lens device, which increases the cluster beam intensity entering and leaving the ion optical part while keeping the beam density unchanged in the prior art, and realizes the focusing and lateral self-constraint functions of the beam of this shape in the direction of the center line, thereby improving the cluster yield.

[0006] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0007] A self-constrained, laterally extended ion optical lens device comprises: a rectangular vacuum chamber and an ion lens device; the ion lens device comprises an entrance slit of the ion optical lens, an exit slit of the ion optical lens, and an electrode group; the electrode group comprises a conical plate electrode group and a parallel plate electrode group; the leading end of the conical plate electrode group forms the entrance slit of the ion optical lens, the trailing end of the conical plate electrode group is connected to the leading end of the parallel plate electrode group, and the trailing end of the parallel plate electrode group forms the exit slit of the ion optical lens;

[0008] A cluster beam generating device outlet is provided on one side of the rectangular parallelepiped vacuum chamber, and the ion lens device is placed in the rectangular parallelepiped vacuum chamber.

[0009] Preferably, the entrance slit of the optical lens, the exit slit of the ion optical lens, the cuboid vacuum chamber and the center line of the cluster ion beam are on the same horizontal plane.

[0010] Preferably, the conical flat plate electrode group consists of one or more pairs of conical flat plate electrodes; the flat plate electrode group includes N groups of parallel plate electrodes parallel to each other.

[0011] Preferably, the width W3 of the rectangular vacuum chamber is greater than the width W2 of the parallel plate electrode, which is greater than the width W1 of the cluster ion beam. When the parallel plate electrode width W2 is significantly longer than the cluster beam generator's exit slit W1, the ions are weakly confined by the electric field forces on both sides. When the parallel plate electrode width W2 is approximately the same as the cluster beam generator's exit slit W1, the ions are significantly confined by the electric field forces on both sides.

[0012] By extending the ion optical lens laterally, when the electrode width W2 is much larger than the cluster beam generator's exit slit W1, the ion beam at the center of the vacuum chamber is essentially unconstrained by the electric field forces on both sides. When the electrode width W2 approaches the cluster beam generator's exit slit W1, the ion beam diverges to both sides. As it approaches the electrode plate edge, it is subjected to inward electric field forces, preventing it from leaving the range of the parallel electrode plates, thus achieving lateral self-confinement of the cluster ions.

[0013] Preferably, the rectangular vacuum chamber is grounded, with a potential of 0V. Because cluster ions are positively charged, the parallel plate electrode groups are all connected to a negative voltage, and each of the N parallel plate electrode groups is connected to an external, adjustable DC power supply. This results in a potential of 0V on both sides of the rectangular vacuum chamber. Since the parallel plate electrode groups are all connected to a negative voltage, a potential difference exists from the two sides of the rectangular vacuum chamber to the electrode groups. Positively charged cluster ions are subjected to an inward electric force at this point, preventing them from continuing to disperse outward and contaminating the chamber walls.

[0014] Preferably, the voltage amplitude of the adjustable DC power supply is controlled within the range of 0 to 3000V.

[0015] Preferably, the parallel electrode plate group realizes the focusing of cluster ions by adjusting the voltage parameters. Different voltage parameters will cause different focusing effects of the cluster ion beam, and the focal positions of the cluster ion beam convergence are different. The method for focusing cluster ions using the above-mentioned cluster ion ion lens device can achieve the best focusing effect by adjusting the voltage parameters. The cluster beam entering the ion optical lens cannot leave the range where the electrode plates are located, and the cluster can be constrained to move between the plates without adding additional conditions. It can be considered that the cluster beams of parallel incidence converge at point F, just like a beam of light is focused on the focus when passing through an optical lens. F is the focus of the electrostatic lens, and the different voltages of the two electrodes will cause the focus of the electrostatic lens to be different. By combining a multi-stage electrostatic lens (a plurality of parallel plate electrodes), the best convergence effect can be achieved.

[0016] The basic principle of focusing is that cluster ions or other charged ions are deflected at the junction of two electrodes. Their axial velocity changes with the potential of their spatial position, and the electric field force acts on them. The further to the sides, the stronger the electric field force. After passing through the electrostatic lens, the cluster ions cannot resume their axial motion and ultimately converge at a single point.

[0017] Compared with the prior art, the present invention achieves the following beneficial effects: a self-constrained, laterally extended ion optical lens device of the present invention increases the intensity of the cluster beam entering and leaving the ion optical section while maintaining the beam density of the prior art, and achieves the focusing of the beam shape toward the centerline and the lateral self-constraint function, ultimately contributing to an increase in cluster yield. The device can increase the ion beam intensity, ultimately increasing the yield of collected clusters. The parallel electrode plate group can achieve focusing of cluster ions, and by adjusting the voltage parameters, the optimal focusing effect can be achieved. The cluster beam entering the ion optical lens cannot leave the range of the electrode plates, and the clusters can be self-constrained to move between the plates without adding additional conditions. The laterally extended ion optical lens can extend the width of the parallel electrode plates as needed, thereby increasing the intensity of the ion beam passing through and the cluster yield, making it an essential device for the commercial production of cluster atoms. The device of the invention can achieve a self-constraint function laterally, so that cluster ions move within the range of the electrode plates and can only exit through the ion optical exit slit, which is beneficial for the mass selector to achieve the screening and separation of corresponding mass clusters. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0019] Figure 1 2. It is a schematic structural diagram of a laterally extended ion optical lens device according to the present invention;

[0020] Figure 2 This is a rear view of the laterally extended ion optical lens device of the present invention;

[0021] Figure 3 This is a schematic diagram of the inward electric field force exerted on cluster ions that diverge to both sides in this embodiment;

[0022] Figure 4 2. This is a schematic diagram of the focusing effect of the laterally extended ion optical lens device of this embodiment;

[0023] Figure 5 is an elongated top view of the laterally extended ion optical lens device of this embodiment;

[0024] In the figure: 1. Rectangular vacuum chamber; 2. Cluster beam generating device outlet; 3. Entrance slit of ion optical lens; 4. Exit slit of ion optical lens; 5. Parallel plate electrode group; 6. Conical flat plate electrode group. DETAILED DESCRIPTION

[0025] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0026] Example 1

[0027] A self-constrained laterally extended ion optical lens device ( Figure 1 ), comprising: a rectangular vacuum chamber 1 and an ion lens device; the ion lens device comprises an entrance slit 3 of the ion optical lens, an exit slit 4 of the ion optical lens and an electrode group; the electrode group comprises a conical plate electrode group 6 and a parallel plate electrode group 5; the front end gap of the conical plate electrode group 6 constitutes the entrance slit 3 of the ion optical lens, the rear end of the conical plate electrode group 6 is connected to the front end of the parallel plate electrode group 5, and the rear end gap of the parallel plate electrode group 5 constitutes the exit slit 4 of the ion optical lens; a cluster beam generating device outlet 2 is provided on one side of the rectangular vacuum chamber 1, and the ion lens device is placed in the cavity of the rectangular vacuum chamber 1.

[0028] The entrance slit 3 of the optical lens, the exit slit 4 of the ion optical lens, the rectangular parallelepiped vacuum chamber 1 and the center line of the cluster ion beam are on the same horizontal plane.

[0029] Among them, the conical flat plate electrode group 6 is composed of three pairs of conical flat plate electrodes; the flat plate electrode group 5 includes 6 groups of parallel plate electrodes parallel to each other. The parallel electrode plates are cut from 3mm thick 6061 aluminum profiles in one piece, and the straightness and deformation error of the overall material are maintained. The parallel electrode plates are composed of 6 groups, and the width of each group from the entrance to the exit is: 120mm, 50mm, 25mm, 50mm, 50mm, and 98mm respectively. The length is 750mm. After the 6 groups of parallel electrode plates are assembled with the frame, the distance between the electrode plates is 54mm, the height of the beam entrance is 31mm, and the overall length of the device is 894mm, the width is 362mm, and the height is 164mm.

[0030] In this embodiment, 2040 aluminum profile is used as the frame to support the electrode plate, and 304 stainless steel is used as the limit and fixing device of the profile. The electrode plate adopts 6061 aluminum alloy as the main material. The aluminum profile frame and the electrode plate are not in contact, and a 30kV ceramic insulator is used to separate them. The 30kV ceramic insulators are respectively fixed on the three supporting points of the 6061 aluminum profile and fixed with M4 flat head screws. Use screws to fasten the 6061 aluminum alloy and the insulator, and then fix the electrode plate to the 2040 aluminum profile frame. Stud pins are used at the four corners of the profile frame so that the entire structure can be adjusted in the up and down and horizontal directions and play a role in supporting the entire device.

[0031] The outlet height of the cluster beam generating device is 2 mm and its width is W1 (cluster ion beam width); the entrance slit 3 of the ion optical lens is 16 mm high and its width is W2, which is larger than W1 and can reach more than 500 mm. The outlet slit 4 of the ion optical lens is 5 mm high and its width is W4, which can be the same as or different from the entrance slit 3 of the ion optical lens.

[0032] Example 2

[0033] A self-constrained, laterally extended ion optical lens device based on Example 1 is described. A rectangular vacuum chamber 1 is grounded to a potential of 0V. The parallel plate electrode groups 5 are all connected to a negative voltage. Six parallel plate electrode groups are each connected to six external adjustable DC power supplies, with voltages ranging from V1 to V6. Different voltage parameters result in different focusing effects on the ion beam and different focal locations of the ion beam. When the potential on both sides of the vacuum chamber is 0V and the parallel plate electrode groups are all connected to a negative voltage, a potential difference exists from the two sides of the vacuum chamber to the electrode groups. Positively charged cluster ions are subjected to an inward electric field force at this point, preventing them from continuing to diverge outward and contaminating the chamber walls.

[0034] When the ion beam has an incident angle of 20°, an incident kinetic energy of 50 eV, and a total of 1000 particles are emitted, a suitable set of parameters is V1 = -400V, V2 = -1700V, V3 = -2400V, V4 = -1250V, V5 = -1550V, and V6 = -2000V. The external vacuum chamber is connected to 0V. The cluster beam is focused longitudinally toward the centerline through an electrostatic lens array composed of six sets of parallel electrode plates. The final ion pass rate through the mass selector is 15%.

[0035] Among them, the cluster ions diverging to both sides are subjected to the inward electric field force as follows Figure 3 And the schematic diagram of the focusing effect of the laterally extended ion optical lens device is as follows Figure 4 shown.

[0036] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus.

[0037] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art will be able to modify the technical solutions described in the aforementioned embodiments or substitute equivalents for some of the technical features. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A self-constrained laterally extended ion optical lens device, characterized in that: include: A rectangular parallelepiped vacuum chamber (1) and an ion lens device; the ion lens device comprises an entrance slit (3) of an ion optical lens, an exit slit (4) of the ion optical lens, and an electrode group; the electrode group comprises a conical plate electrode group (6) and a parallel plate electrode group (5); the front end slit of the conical plate electrode group (6) constitutes the entrance slit (3) of the ion optical lens, the rear end of the conical plate electrode group (6) is connected to the front end of the parallel plate electrode group (5), and the rear end slit of the parallel plate electrode group (5) constitutes the exit slit (4) of the ion optical lens; A cluster beam generating device outlet (2) is provided on one side of the rectangular parallelepiped vacuum chamber (1), and the ion lens device is placed inside the rectangular parallelepiped vacuum chamber (1).

2. The self-constrained laterally extended ion optical lens device according to claim 1, characterized in that: The entrance slit (3) of the optical lens, the exit slit (4) of the ion optical lens, the rectangular parallelepiped vacuum chamber (1) and the center line of the cluster ion beam are on the same horizontal plane.

3. The self-constrained laterally extended ion optical lens device according to claim 1, characterized in that: The conical flat plate electrode group (6) is composed of one or more pairs of conical flat plate electrodes; the flat plate electrode group (5) includes N groups of parallel plate electrodes that are parallel to each other.

4. The self-constrained laterally extended ion optical lens device according to claim 3, characterized in that: The width W3 of the rectangular parallelepiped vacuum chamber (1) is greater than the width W2 of the parallel plate electrode and greater than the width W1 of the cluster ion beam.

5. The self-constrained laterally extended ion optical lens device according to claim 1, characterized in that: The rectangular parallelepiped vacuum chamber (1) is grounded, and its potential is 0V. The parallel plate electrode groups (5) are all connected to a negative voltage, and the N groups of parallel plate electrodes are respectively connected to N adjustable DC power supplies.

6. The self-constrained laterally extended ion optical lens device according to claim 5, characterized in that: The voltage amplitude of the adjustable DC power supply is controlled within the range of 0 to 3000V.

7. The self-constrained laterally extended ion optical lens device according to claim 1, characterized in that: The parallel electrode plate group (5) achieves cluster ion focusing by adjusting voltage parameters. Different voltage parameters will result in different focusing effects of the cluster ion beam and different focal positions of the cluster ion beam.

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