CN112164644A

CN112164644A - Penning ion source

Info

Publication number: CN112164644A
Application number: CN202011156701.6A
Authority: CN
Inventors: 郭方准; 石晓倩
Original assignee: Dalian Jiaotong University
Current assignee: Dalian Jiaotong University
Priority date: 2020-10-26
Filing date: 2020-10-26
Publication date: 2021-01-01

Abstract

The invention relates to a penning ion source which mainly comprises a magnet mechanism, an ion generating and extracting mechanism and an ion accelerating mechanism. Argon ions are generated in this core configuration and acceleration of the ions is accomplished. The magnet mechanism is composed of a magnet outer cover and a magnet, Lorentz force is applied to electrons, the electrons do spiral line motion, and the collision probability of the electrons and argon atoms is increased; the ion generating and extracting mechanism comprises an anode cylinder, a cathode pressing sheet with holes and a cathode shielding cover, wherein argon enters the anode cylinder, because of the existence of partial electrons, the electrons collide with argon atoms under the action of an electric field and a magnetic field to generate argon ions, the generated argon ions are ejected out through the cathode pressing sheet with holes, and the pointing direction of ion beam current can be restrained by the action of the holes, and the size of the beam current can also be adjusted; the invention also comprises an accelerating cylinder which is grounded and used for attracting ions to accelerate and eject from the small hole. The invention has simple and compact structure and can continuously and reliably work.

Description

Penning ion source

Technical Field

The invention relates to a small charged particle emission device of ultrahigh vacuum equipment, in particular to a penning ion source.

Background

The research content of surface science mainly comprises surface state, surface diffusion, surface reconstruction, surface phonon, surface plasmon polariton, electron emission and tunneling effect, spin electron, self-assembly, nano structure and the like. The structure for obtaining and controlling the surface atom precision is the foundation of surface science and is the premise of nanotechnology. Typical surface treatments are dissociation, annealing and ion sputtering, which are almost standard configurations for surface analysis instruments. Annealing is relatively simple, as long as accurate temperature control can be achieved. Ion sputtering is performed by using an ion source gun, which ionizes and accelerates large-mass and inactive argon (Ar) atoms to thousands of electron volts and irradiates the surface of a sample. There are many types of ion sources, including cold cathode penning ion sources, hot cathode ion sources, electron cyclotron resonance ion sources, and the like. The penning ion source is a relatively early-researched ion source, and is developed to the present day and becomes a relatively mature ion source. The existing penning ion source has long service life, but has poor sustainable capability and poor high-temperature baking resistance, and cannot be widely applied.

Disclosure of Invention

In accordance with the above-mentioned technical problem, there is provided a penning ion source: the technical means adopted by the invention are as follows:

a penning ion source comprises a magnet mechanism, an ion generating and extracting mechanism, and an ion accelerating mechanism.

The magnet mechanism is covered outside the outer cover and used for applying Lorentz force to electrons;

the ion generating and extracting mechanism comprises an outer cover, a cathode shielding cover, cathode pressing sheets and an anode cylinder, wherein the outer cover is connected with an electrode flange, the anode cylinder is connected with an air inlet flange, the cathode pressing sheets are arranged at two ends of the cathode shielding cover and are insulated by insulating ceramics, and one of the cathode pressing sheets is provided with a hole and used as an ion output port;

the ion accelerating mechanism comprises an accelerating cylinder, a fixing ring and a pressing plate, wherein the accelerating cylinder, the fixing ring and the pressing plate are connected through threads, and the pressing plate is further connected with an interface flange.

Further, the magnet mechanism comprises a magnet and a magnet cover, and the magnet cover are attracted together through magnetic force.

Furthermore, magnetic stainless steel is arranged between the accelerating cylinder and the cathode pressing sheet with the hole.

Compared with the prior art, the invention has the following beneficial effects:

1. the penning ion source is a cold cathode ion source, the problems of filament breakage and the like do not exist, and the cruising ability is strong.

2. The ion energy is adjustable, and the maximum is 5 kV; the beam current is adjustable, and the size of the small hole is adjusted.

3. The cathode has no extra heat source, the structure is simple and compact, and the device can continuously and reliably work.

4. The acceleration cylinder can accelerate and focus.

5. The penning ion source is made of SUS304, SUS430, magnetite and ceramic, so that the penning ion source can resist high-temperature baking at 220 ℃.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.

FIG. 1 is a schematic diagram of the penning ion source.

Fig. 2 is a cross-sectional view of a penning ion source.

Fig. 3 is a partially enlarged view.

In the figure: 1. a magnet mechanism; 2. an electrode flange; 3. an air inlet flange; 4. a magnet; 5. a magnet housing; 6. a housing; 7. an insulating plate; 8. an interface flange; 9. a cathode shield; 10. cathode tabletting; 11. an anode cylinder; 12. an insulating ceramic; 13. cathode tabletting with holes; 14. magnetic stainless steel; 15. a collimating aperture; 16. an acceleration cylinder; 17. a fixing ring; 18. and (7) pressing a plate.

Detailed Description

The present invention will be described in detail below with reference to the drawings and examples, but the present invention is not limited to the specific examples.

As shown in fig. 1-3, the penning ion source comprises a magnet mechanism 1, an ion generating and extracting mechanism, and an ion accelerating mechanism.

The magnet mechanism includes a magnet 4 and a magnet cover 5. The magnetite passes through magnetic force with the magnetite dustcoat and closely adsorbs together, covers the magnetite system on dustcoat 6, is equipped with insulation board 7 between dustcoat 6 and the cathode shield cover 9, the dustcoat is connected with electrode flange 2, and the magnetite system can apply the lorentz power for the electron, and the helix motion is done to the electron, increases the collision probability of electron and argon gas atom, and in this embodiment, magnetite dustcoat 5 can be dismantled, and its below is equipped with the breach that matches two electrode flanges 2 and air intake flange 3.

The ion generating and extracting mechanism comprises a cathode shielding cover 9, a cathode pressing sheet 10, an anode cylinder 11, a cathode pressing sheet 13 with holes and magnetic stainless steel 14. Argon can get into in the anode cylinder 11 through air inlet flange 3, and the partial electron in the anode cylinder can make the helix motion under the effect of electric field and magnetic field this moment, collides with argon atom and produces argon ion in the motion process. The cathode pressing sheet 10 is arranged in the cathode shielding case and is insulated by three insulating ceramics 12, and the cathode pressing sheet of the cathode shielding case is a perforated cathode pressing sheet 13 with a small hole at one end and is used as an ion output port. The magnetic stainless steel 14 can enable a magnetic field to penetrate through the magnetic stainless steel, so that magnetic lines of force are bound, the cathode pressing sheet 13 with the holes can be replaced, and the size of the small holes determines the density of ejected deionized water, so that the beam intensity is determined. A collimation hole 15 is also arranged between the acceleration cylinder and the cathode pressing sheet with the hole and used for collimating ions, so that the diffused ions can collide with the collimation hole to disappear.

The ion accelerating mechanism includes an accelerating cylinder 16, a fixing ring 17, and a pressing plate 18. The fixed ring of the acceleration cylinder is in threaded connection with the pressing plate, the pressing plate is simultaneously connected with the interface flange 8 through threads, the acceleration cylinder is an uncharged cylinder, ions are positively charged, the acceleration cylinder is lower than the ion potential, the ions can be attracted and drawn out, the acceleration effect is achieved, and the focusing effect is also realized because the ions with partial divergence can collide with the wall to die.

The interface flange of the penning ion source is connected with the flange of the ultra-vacuum chamber, and the penning ion source is an electron impact type ion source excited by reciprocating oscillation electrons. The penning ion source is filled with gas to be ionized, when discharging, a stable strong magnetic field passes through the ion source in the axial direction, and a discharge voltage is applied between the cathode and the anode cylinder. The electrons are accelerated by the electric field in the gap between the anode and the cathode to obtain a certain initial velocity. The movement of electrons in the anode cylinder can be decomposed into a movement perpendicular to the axis of the anode cylinder and a movement parallel to the axis of the anode cylinder: in the direction vertical to the axis of the anode cylinder, electrons are restrained by an electric field and a magnetic field in a discharge area consisting of a cathode and an anode to do spiral motion; meanwhile, in the direction parallel to the axis of the anode cylinder, electrons are acted by axial electric field force and oscillate back and forth between the cathodes. Therefore, the movement distance of electrons before collision and extinction is greatly increased, the probability of collision between each electron and space neutral particles is improved, the concentration of plasma in the discharge cavity is improved, and the discharge structure can normally discharge under very low pressure. The pressure and plasma density in the discharge chamber are higher than those in the outer vacuum environment. If the direct current discharge ion source can discharge without applying a magnetic field, the ion beam density is increased after the magnetic field is applied. The ion energy can be adjusted at will within the range of 0-5 KV, and proper energy can be selected according to scenes.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A penning ion source characterized by: comprises a magnet mechanism, an ion generating and extracting mechanism and an ion accelerating mechanism,

the ion generating and extracting mechanism comprises an outer cover, a cathode shielding cover, cathode pressing sheets and an anode cylinder, wherein the outer cover is connected with an electrode flange, the anode cylinder is connected with an air inlet flange, the cathode pressing sheets are arranged at two ends of the cathode shielding cover and are insulated by insulating ceramics, and at least one cathode pressing sheet is provided with a hole and is used as an ion output port;

2. The penning ion source of claim 1, wherein the magnet mechanism comprises a magnet and a magnet housing, and the magnet housing are attracted together by magnetic force.

3. The penning ion source of claim 1, wherein a magnetic stainless steel is disposed between the acceleration cylinder and the perforated cathode plate.