Gas and solid dual-mode ion source

Abstract

The invention discloses a gas and solid dual-mode ion source, which comprises an ECR (electron cyclotron resonance) cavity, a magnet, a cylindrical sample target, a microwave window, a microwave waveguide, a gas inlet, an ion exit slit and a grid, according to the dual-mode ion source, when the positive electrode of a direct-current power supply is connected to an ECR cavity, and the negative electrode of the direct-current power supply is connected to a grid electrode, the dual-mode ion source is in a gas ion source working state; when the positive electrode of a sputtering power supply is connected to the ECR cavity, the negative electrode of the sputtering power supply is connected to the cylindrical sample target, and after stable sputtering is achieved, when the positive electrode of a direct-current power supply is connected to the ECR cavity, and the negative electrode of the direct-current power supply is connected to the grid electrode, the dual-mode ion source is in a solid ion source working state. The dual-mode ion source is compact in structure, reliable and stable in work, low in use cost and high in ionization rate. The ion source can be used as a gas ion source, can also be used as a solid ion source, can be switched in the working process, and can be applied to mass spectrometers, ion injection equipment, etching equipment and the like.

Description

Technical Field

[0001] The invention belongs to the technical field of ion sources, and in particular relates to a gas and solid dual-mode ion source. Background Art

[0002] An ion source is a device that ionizes neutral atoms or molecules and draws out an ion beam from them. The ion source is one of the key components of various types of ion accelerators, mass spectrometers, electromagnetic isotope separators, ion implanters, ion beam etching devices, ion thrusters and other equipment. There are two main ways to generate ions: by discharging in the gas and by bombarding or evaporating solids. According to the classification of the ions produced, ion sources are divided into gas ion sources and solid ion sources.

[0003] A Chinese patent application with application number CN202180027304.5 discloses a microwave-driven plasma ion source for ionizing a sample to be ionized into sample ions, comprising a sample inlet (6), a microwave generator (10), and a plasma torch (20), wherein the plasma ion source comprises a shielding layer (4) for shielding microwaves transmitted from the interior (3) of the microwave-driven plasma ion source to the exterior of the microwave-driven plasma ion source, wherein the shielding layer (4) comprises a shielding outlet (5) for discharging the plasma (101) and the sample ions from the interior (3) of the microwave-driven plasma ion source to the exterior of the microwave-driven plasma ion source substantially along the directional direction of the plasma torch, and the shielding outlet (5) has a shielding aperture; wherein the shielding outlet (5) is fluidically coupled to the torch outlet (22) to discharge the plasma (101) and the sample ions from the interior (21) of the plasma torch (20) to the exterior of the microwave-driven plasma ion source substantially along the directional direction of the plasma torch. The invention can optimize its operating parameters simply and stably to maximize the generation of sample ions, but the invention cannot meet the process that requires both gas ions and solid ions. The Chinese patent with application number CN201811617306.6 discloses a high-current ion source device that can generate multiple ions. The laser microwave ion source includes: a magnetron 1, a waveguide system 2, a discharge chamber 3, a magnet system 4, a gas supply system, a solid target 8 and a laser generator 5, a galvanometer 6, a field mirror 7, etc. When the ion source is working, the discharge chamber 3 hits the target 8, which can ionize the gas in the discharge chamber 3 to generate electrons and ions, and can evaporate the material on the target 8 to form corresponding vapor in the discharge chamber 3; the magnetron 1 generates microwaves through the waveguide system 2 into the plasma cavity 3, and under the influence of the magnet system 4, the electrons in the cavity cyclotron run at the same frequency as the microwave frequency, and the two resonate, and the electrons obtain very high energy, so that the gas in the discharge chamber 3 is further ionized to form an iso-high density plasma. This invention uses an additional high-energy laser to generate electrons or evaporate solids. It has a complex structure and large size. It cannot switch between generating electrons or evaporating solids, and the target material needs to be replaced. More importantly, the method of exciting evaporated solids easily contaminates the chamber, especially the optical lens, and affects the incidence of the laser. Therefore, it is urgent to develop a gas and solid dual-mode ion source that does not require additional electron or evaporation sources, can switch freely between gas ions and solid ions, and does not require the replacement of target materials. Summary of the invention

[0004] In order to solve the above problems, the present invention provides a gas-solid dual-mode ion source, which can achieve a high ionization rate and is suitable for direct ionization of solid samples. Gas can also be used as an ionization source. The ion beam generated by sputtering is highly controllable and has little pollution. It also has a compact structure, stable operation and low cost.

[0005] The technical solution of the present invention is as follows:

[0006] One of the purposes of the present invention is to provide a gas and solid dual-mode ion source, comprising:

[0007] ECR cavity;

[0008] Magnet: Wrapped outside the ECR cavity, forming an axial magnetic field inside the ECR cavity, forming an electronic ECR resonance surface at a distance of / to / radius from the inner cavity wall of the ECR cavity, and by adjusting the microwave power and gas pressure, the microwave resonates in the magnetic field of the magnet, so that the gas in the ECR cavity can achieve stable plasma discharge;

[0009] Cylindrical sample target: arranged on the inner surface of the ECR cavity, the cylindrical sample target is consistent with the axial height of the magnet, and the cylindrical sample target is insulated from the ECR cavity;

[0010] Microwave window: It is set on the ECR cavity, and microwaves are transmitted into the ECR cavity through the microwave window;

[0011] Microwave waveguide: It is arranged outside the microwave window and is used to transmit microwaves into the ECR cavity through the microwave window;

[0012] Gas inlet: It is set on the ECR chamber, and the gas enters the ECR chamber through the gas inlet;

[0013] Ion exit slit: set on the ECR cavity;

[0014] Grid: It is set outside the ion exit slit and is used to extract the ions generated by the ionization of the gas or cylindrical sample target from the ion exit slit;

[0015] When the positive pole of the DC power supply is connected to the ECR cavity and the negative pole is connected to the grid, the dual-mode ion source is in a gas ion source working state; when the positive pole of the sputtering power supply is connected to the ECR cavity and the negative pole is connected to the cylindrical sample target, after stable sputtering is achieved, the positive pole of the DC power supply is connected to the ECR cavity and the negative pole is connected to the grid, the dual-mode ion source is in a solid ion source working state.

[0016] Furthermore, insulating ceramics are arranged between the cylindrical sample target and the ECR cavity, and the cylindrical sample target is insulated from the ECR cavity by the insulating ceramics.

[0017] Furthermore, when the dual-mode ion source is in a gas ion source working state, the gas entering the ECR chamber through the gas inlet is a raw material gas.

[0018] Furthermore, when the dual-mode ion source is in a solid ion source working state, the gas entering the ECR chamber through the gas inlet is an inert gas.

[0019] Furthermore, the ECR cavity is a cylindrical structure.

[0020] Furthermore, the ECR cavity is made of stainless steel.

[0021] Furthermore, the cylindrical sample target is made of a conductive material.

[0022] Furthermore, the conductive material is metal or graphite.

[0023] Furthermore, the microwave window is made of dielectric material.

[0024] Furthermore, the dielectric material is quartz, boron nitride or diamond.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] 1. The present invention provides a gas and solid dual-mode ion source, which realizes the solid sputtering and gas ionization capabilities under the same magnetic field constraint through an innovative sputtering-assisted ECR ion source structure, greatly reduces the complexity of the ion source, and realizes a highly reliable gas ion and solid ion shared structure. The present invention can be used as a gas ion source or a solid ion source, and can be switched during operation. In the gas ion source working mode, the microwave waveguide transmits microwaves to the ECR cavity through the microwave window, and the microwave-driven electrons are cyclotron accelerated in the magnetic field generated by the magnet, exciting the working gas to produce high-density plasma, and the ion exit slit extracts the ions under the action of the bias voltage and enters the corresponding equipment. In the solid ion source working mode, the microwave waveguide transmits microwaves to the ECR cavity through the microwave window. In the magnetic field generated by the magnet, microwaves drive electrons to perform cyclotron acceleration, excite the inert gas to produce high-density plasma, and bombard the solid sample target under the action of bias voltage to produce some solid ions and some solid atoms. In the magnetic field generated by the magnet, microwaves drive electrons to perform cyclotron acceleration, excite the solid atoms to further ionize and produce high-density plasma. Under the action of bias voltage, the ion exit slit extracts the ions and enters the corresponding equipment.

[0027] 2. The gas and solid dual-mode ion source provided by the present invention has a high ionization rate in the working mode of the solid ion source. After the atoms are sputtered from the solid surface, they are ionized after repeated collisions with high-energy electrons bound in the magnetic field, and further collide with gas ions after entering the vicinity of the central area of ​​the ECR chamber, and finally extracted from the ion exit slit. The present invention has a compact structure, reliable and stable operation, and low cost, and can be applied to mass spectrometers, ion implantation equipment, etching equipment, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 A cross-sectional view of a gas and solid dual-mode ion source provided by the present invention;

[0029] Figure 2 A top view of a gas and solid dual-mode ion source provided by the present invention.

[0030] In the figure: 1. ECR cavity; 2. magnet; 3. insulating ceramic; 4. cylindrical sample target; 5. microwave window; 6. microwave waveguide; 7. gas inlet; 8. ion exit slit; 9. gate. DETAILED DESCRIPTION

[0031] The following is combined with the preferred embodiment and with reference to the attached Figure 1-2 , the present invention is further described. The endpoints and any values ​​of the ranges disclosed in the present invention are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values; for numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be regarded as specifically disclosed herein; the materials, reagents, etc. used in the following examples, unless otherwise specified, can be obtained from commercial channels; the experimental methods in the following examples, unless otherwise specified, are all conventional methods.

[0032] Example 1

[0033] This embodiment provides a gas and solid dual-mode ion source, such as Figure 1-2 As shown, including:

[0034] ECR chamber 1, in this embodiment, the ECR chamber 1 is a cylindrical structure and is made of stainless steel;

[0035] Magnet 2: Wrapped outside the ECR cavity 1, an axial magnetic field is formed inside the ECR cavity 1, and an electron ECR resonance surface is formed at a radius of 1 / 5 to 1 / 2 of the inner cavity wall of the ECR cavity 1. By adjusting the microwave power and gas pressure, the microwave resonates in the magnetic field of the magnet 2, so that the gas in the ECR cavity 1 can achieve stable plasma discharge;

[0036] In this embodiment, an insulating ceramic 3 is provided between the cylindrical sample target 4 and the ECR cavity 1, and the cylindrical sample target 4 is insulated from the ECR cavity 1 by the insulating ceramic 3;

[0037] Cylindrical sample target 4: arranged on the inner surface of the ECR cavity 1, the axial height of the cylindrical sample target 4 is consistent with that of the magnet 2, and the cylindrical sample target 4 is insulated from the ECR cavity 1;

[0038] In this embodiment, the cylindrical sample target 4 is graphite; in another embodiment, the cylindrical sample target 4 can also be metal;

[0039] Microwave window 5: arranged on the ECR cavity 1, microwaves are transmitted into the ECR cavity 1 through the microwave window 5;

[0040] In this embodiment, the microwave window 5 is made of quartz; in another embodiment, the microwave window 5 may also be made of boron carbide or diamond;

[0041] Microwave waveguide 6: arranged outside the microwave window 5, used for transmitting microwaves into the ECR cavity 1 through the microwave window 5;

[0042] Gas inlet 7: arranged on the ECR chamber 1, through which the gas enters the ECR chamber 1;

[0043] Ion exit slit 8: arranged on the ECR cavity 1;

[0044] Grid 9: arranged outside the ion exit slit 8, used to extract ions generated by ionization of the gas or cylindrical sample target 4 from the ion exit slit 8;

[0045] When the positive pole of the DC power supply is connected to the ECR chamber 1 and the negative pole is connected to the gate 9, the dual-mode ion source is in a gas ion source working state; when the positive pole of the sputtering power supply is connected to the ECR chamber 1 and the negative pole is connected to the cylindrical sample target 4, after stable sputtering is achieved, the positive pole of the DC power supply is connected to the ECR chamber 1 and the negative pole is connected to the gate 9, and the dual-mode ion source is in a solid ion source working state.

[0046] Specifically, in the gas ion source working mode, the raw material gas A enters the ECR chamber 1 from the gas inlet 7, and when the pressure in the ECR chamber 1 reaches the working pressure (10 -2-10Pa), the external microwave generator generates 2.45GHz microwaves which are transmitted into the ECR cavity 1 through the microwave window by the microwave waveguide 5. By adjusting the microwave power to 150W and the gas pressure to 2Pa, the microwaves resonate in the magnetic field of the magnet 2, so that the raw material gas in the ECR cavity 1 achieves stable plasma discharge, and the gate DC power supply is turned on. The positive pole of the DC power supply is connected to the ECR cavity 1, and the negative pole is connected to the gate 9. The dual-mode ion source is in the gas ion source working state, and the ions generated by the ionization of the raw material gas are extracted from the ion exit slit 8 through the gate 9.

[0047] The working principle of the gas ion source is as follows: the microwave waveguide 6 transmits microwaves to the ECR cavity 1 through the microwave window 5, and the microwaves drive the electrons to perform cyclotron acceleration in the magnetic field generated by the magnet 2, exciting the working gas to produce high-density plasma, and the ion exit slit 8 extracts the ions under the action of the bias voltage and enters the corresponding equipment.

[0048] Specifically, in the solid ion source working mode, an inert gas is introduced into the ECR chamber 1 from the gas inlet 7, and the pressure in the ECR chamber 1 reaches the working pressure (10 -2 -10Pa), the microwave generator generates 2.45G microwaves which are transmitted into the ECR cavity 1 through the microwave window by the microwave waveguide 5. By adjusting the microwave power to 100W and the gas pressure to 0.3Pa, the microwaves resonate in the magnetic field of the magnet 2, so that the inert gas in the ECR cavity 1 achieves stable plasma discharge, and the sputtering power supply is turned on. The positive pole of the sputtering power supply is connected to the ECR cavity 1, and the negative pole is connected to the cylindrical sample target 4. Increase the voltage of the sputtering power supply so that the sputtering voltage is 325V and the current is 52mA to achieve stable sputtering. Gradually reduce the chamber pressure to 0.01Pa, at which time most of the ions are solid ions. Turn on the gate DC power supply. The dual-mode ion source is in the solid ion source working state, and the ions generated by the ionization of the cylindrical sample target 4 are extracted from the ion exit slit 8 through the gate 9.

[0049] The working principle of the solid ion source is as follows: the microwave waveguide 6 transmits the microwave to the ECR cavity 1 through the microwave window 5, and the microwave drives the electrons to perform cyclotron acceleration in the magnetic field generated by the magnet 2, exciting the inert gas to produce high-density plasma, and bombarding the cylindrical sample target 4 under the action of bias voltage, generating some solid ions and some solid atoms, and the microwave drives the electrons to perform cyclotron acceleration in the magnetic field generated by the magnet 2, exciting the solid atoms to further ionize and generate high-density plasma, and the ion exit slit 8 extracts the ions under the action of bias voltage and enters the corresponding equipment.

[0050] The above is only a preferred embodiment of the present invention. It should be pointed out that a person skilled in the art can make several modifications and improvements without departing from the inventive concept of the present invention, which all belong to the protection scope of the present invention.

Claims

1. A gas and solid dual-mode ion source, characterized in that: include: ECR chamber (1); A magnet (2) is wrapped around the outside of the ECR cavity (1), forming an axial magnetic field inside the ECR cavity (1), and forming an electron ECR resonance surface at a radius of 1 / 5 to 1 / 2 of the inner cavity wall of the ECR cavity (1). By adjusting the microwave power and the gas pressure, the microwave resonates in the magnetic field of the magnet (2), so that the gas in the ECR cavity (1) can achieve stable plasma discharge; A cylindrical sample target (4) is arranged on the inner surface of the ECR cavity (1), the axial height of the cylindrical sample target (4) and the magnet (2) are consistent, and the cylindrical sample target (4) is insulated from the ECR cavity (1); A microwave window (5) is arranged on the ECR cavity (1), and microwaves are transmitted into the ECR cavity (1) through the microwave window (5); A microwave waveguide (6) is arranged outside the microwave window (5) and is used to transmit microwaves into the ECR cavity (1) through the microwave window (5); A gas inlet (7) is arranged on the ECR chamber (1), and gas enters the ECR chamber (1) through the gas inlet (7); Ion exit slit (8): arranged on the ECR cavity (1); A grid (9) is arranged outside the ion exit slit (8) and is used to extract ions generated by ionization of the gas or cylindrical sample target (4) from the ion exit slit (8); When the positive electrode of the DC power supply is connected to the ECR chamber (1) and the negative electrode is connected to the grid (9), the dual-mode ion source is in a gas ion source working state; when the positive electrode of the sputtering power supply is connected to the ECR chamber (1) and the negative electrode is connected to the cylindrical sample target (4), after stable sputtering is achieved, the positive electrode of the DC power supply is connected to the ECR chamber (1) and the negative electrode is connected to the grid (9), and the dual-mode ion source is in a solid ion source working state.

2. A gas and solid dual-mode ion source according to claim 1, characterized in that: An insulating ceramic (3) is arranged between the cylindrical sample target (4) and the ECR cavity (1), and the cylindrical sample target (4) is insulated from the ECR cavity (1) by the insulating ceramic (3).

3. A gas-solid dual-mode ion source according to claim 1, characterized in that: When the dual-mode ion source is in a gas ion source working state, the gas entering the ECR chamber (1) through the gas inlet (7) is the raw material gas.

4. A gas-solid dual-mode ion source according to claim 1, characterized in that: When the dual-mode ion source is in a solid ion source working state, the gas entering the ECR chamber (1) through the gas inlet (7) is an inert gas.

5. The gas-solid dual-mode ion source according to claim 1, characterized in that: The ECR chamber (1) is a cylindrical structure.

6. The gas-solid dual-mode ion source according to claim 1, characterized in that: The ECR chamber (1) is made of stainless steel.

7. The gas-solid dual-mode ion source according to claim 1, characterized in that: The cylindrical sample target (4) is made of conductive material.

8. A gas and solid dual-mode ion source according to claim 7, characterized in that: The conductive material is metal or graphite.

9. The gas-solid dual-mode ion source according to claim 1, characterized in that: The microwave window (5) is made of dielectric material.

10. The gas-solid dual-mode ion source according to claim 9, characterized in that: The dielectric material is quartz, boron nitride or diamond.

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