Ion source for high energy ion implanter

Abstract

This invention relates to an ion source for a high-energy ion implanter, comprising an inlet, a cathode, a discharge chamber, and an extraction system. The cathode is installed in the discharge chamber, one end of which is connected to the inlet, and the other end to the extraction system. The central axes of the inlet, cathode, discharge chamber, and extraction system are all aligned. The inlet is used to introduce gas. The cathode emits electrons in the discharge chamber, creating an electric field between the chamber and the cathode. The electrons emitted by the cathode gain kinetic energy under the influence of this field and collide with the introduced gas, ionizing the gas into gaseous ions. These gaseous ions then collide with sputtering electrodes in the discharge chamber, sputtering solid atoms and further ionizing them to generate a solid particle ion beam. The extraction system extracts and transmits the ion beam. A modular design allows for switchable operation in both gas and sputtering modes, enabling the generation of various ions, including non-metallic and metallic ions.

Description

Technical Field

[0001] This invention belongs to the field of ion sources, and specifically relates to an ion source for high-energy ion implanters. Background Technology

[0002] Ion sources are mainly used in equipment such as ion accelerators, mass spectrometers, ion implanters, electromagnetic isotope separators, ion beam etching devices, ion thrusters, and neutral beam injectors in controlled fusion devices.

[0003] Traditional ion sources typically produce only a single or specific type of ion, and their fixed structure makes disassembly, maintenance, and replacement of key components difficult, severely limiting their flexibility in multi-ion beam applications. For example, common gas ion sources can only ionize specific working gases, while metal ion sources rely on specific target materials and cannot achieve rapid switching between multiple ion types within the same device. Traditional filament structures using U-shaped cathodes suffer from low electron emission efficiency, directly affecting beam intensity and stability. Furthermore, previous sputtering sources for generating metal ions also faced the risk of cesium contamination, as well as the manufacturing and maintenance costs associated with corrosion resistance. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide an ion source for a high-energy ion implanter. Through modular design, it enables switchable operation in both gas mode and sputtering mode, flexibly generating ion sources including B... + P + As + Non-metallic ions and Fe + It contains a variety of ions, including metal ions, and supports the generation of ions with higher charge states.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is: an ion source for a high-energy ion implanter, the ion source comprising an inlet, a cathode, a discharge chamber, and an extraction system, wherein the cathode is installed in the discharge chamber via a first connecting flange, one end of the discharge chamber is connected to the inlet via the first connecting flange, and the other end is connected to the extraction system via a second connecting flange, the inlet, the cathode, the central axis of the discharge chamber, and the central axis of the extraction system are all on the same straight line, the inlet is used to introduce gas, the cathode is used to emit electrons in the discharge chamber, the discharge chamber is used to form an electric field with the cathode, so that the electrons emitted by the cathode gain kinetic energy under the action of the electric field and collide with the introduced gas, ionizing the gas into gaseous ions, and the gaseous ions collide with the sputtering electrode in the discharge chamber to sputter out solid atoms, which are further ionized to generate solid particle ions, and the extraction system is used to extract the generated ions and transport them backward.

[0006] Furthermore, the cathode includes a cathode tube, a filament, and a cathode disk. The air inlet is connected to the outer flange of the first connecting flange. One end of the cathode tube is installed on the inner flange of the first connecting flange, and the other end of the cathode tube is installed on the cathode disk. One end of the filament is fixed on the cathode disk and is evenly arranged around the cathode tube.

[0007] Furthermore, a reflective electrode is provided between the cathode tube and the inner flange of the first connecting flange.

[0008] Furthermore, the filament is in the shape of a spiral spring.

[0009] Furthermore, the filament is made of tantalum wire.

[0010] Furthermore, the discharge chamber includes an anode, an ionization chamber, and a sputtering electrode. The anode is disposed at the top of the ionization chamber and is powered to initiate an arc. The ionization chamber provides space for the ionization of the introduced gas. The sputtering electrode is disposed at the outlet of the ionization chamber to generate a solid ion beam after being bombarded by gaseous ions.

[0011] Furthermore, the extraction system includes an interface flange, an insulating support, an extraction cavity, a ground electrode, and a suppression electrode. The interface flange is connected to the extraction cavity. There is a potential difference between the anode of the ionization chamber and the ground electrode of the extraction system, which allows the ion beam generated in the ionization chamber to be transmitted backward. The insulating support is used to isolate the high voltage potential generated by the anode from the ground potential generated by the ground electrode. The suppression electrode is used to prevent the returned electrons from interfering with the beam measurement at the Faraday tube at the rear end of the ion source.

[0012] Furthermore, the discharge chamber includes an outer copper wall and an internal ionization space, with several permanent magnets arranged in an array on the circumference of the outer copper wall in a direction parallel to the cathode tube.

[0013] Furthermore, the N and S poles of the permanent magnets are arranged alternately on the same circumference, and several permanent magnets are evenly arranged along the circumference of the outer copper wall, with the magnetized surface pointing towards the center of the ionization chamber, forming a longitudinal tangential magnetic field in the internal ionization space.

[0014] Furthermore, the permanent magnet is an Nd-Fe-B permanent magnet.

[0015] The beneficial technical effects of this invention are as follows: First, the modular structure design of the detachable cathode chamber, discharge chamber, and extraction system greatly improves the maintainability of the equipment. Second, the flexible switching between three operating modes significantly expands the application range of the ion source. Finally, compared with the traditional U-shaped cathode, the unique helical spring-shaped cathode structure increases the surface area of ​​the filament emitting electrons, significantly improving electron emission efficiency and beam intensity. The method of generating metal ions by sputtering also avoids the chemical pollution risk caused by the introduction of cesium vapor. Furthermore, since there is no cesium consumption issue, it can operate stably for a long time, making it suitable for continuous production environments and improving system stability. It has significant application value in fields such as semiconductor doping, material modification, and nuclear physics research. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of an ion source for a high-energy ion implanter, as shown in Embodiment 1 of the present invention.

[0017] Figure 2 This is a schematic diagram of the structure of an ion source for a high-energy ion implanter, as shown in Embodiment 1 of the present invention.

[0018] Wherein: 1-interface flange; 2-insulating support; 3-ionization chamber; 4-anode; 5-air inlet; 6-cathode tube; 7-filament; 8-cathode disk; 9-sputtering electrode; 10-suppression electrode; 11-ground electrode. Detailed Implementation

[0019] The present invention will now be further described with reference to the accompanying drawings and specific embodiments.

[0020] Example 1

[0021] like Figure 1 As shown, this embodiment of the invention provides an ion source for a high-energy ion implanter, including a cathode, a discharge chamber, and an extraction system. The cathode is installed in the discharge chamber via a first connecting flange. One end of the discharge chamber is connected to the gas inlet 5 via the first connecting flange, and the other end is connected to the extraction system. The discharge chamber and the extraction system are connected via a second connecting flange. The gas inlet 5, the cathode, the central axis of the discharge chamber, and the central axis of the extraction system are all on the same straight line. The gas inlet 5 is used to introduce gas. The cathode is used to emit electrons in the discharge chamber. The discharge chamber is used to form an electric field with the cathode, so that the electrons emitted by the cathode gain kinetic energy under the action of the electric field and collide with the introduced gas, ionizing the gas into gaseous ions. The gaseous ions then bombard the sputtering electrode 9, sputtering out solid atoms and further ionizing them to generate a solid particle ion beam. The extraction system is used to extract the ion beam and transmit it backward.

[0022] The cathode comprises a cathode tube 6, a filament 7, and a cathode disk 8. The air inlet 5 is connected to the outer flange of the first connecting flange. One end of the cathode tube 6 is mounted on the inner flange of the first connecting flange, and the other end is mounted on the cathode disk 8. One end of the filament 7 is fixed to the cathode disk 8 and evenly distributed around the cathode tube 6. A reflective electrode is placed between the cathode tube 6 and the inner flange of the first connecting flange. The reflective electrode confines the ionization space, increasing the probability that electrons emitted by the cathode will collide with the incoming gas and ionize it, thus improving ionization efficiency.

[0023] In this embodiment of the invention, the filament 7 is made of tantalum wire with a diameter of 0.5 mm, wound into a spring shape, with a total of four filaments 7. The four filaments 7 are fixed in parallel on the cathode disk 8. In fact, there is no limitation on the diameter of the tantalum wire or the number of filaments 7.

[0024] The discharge chamber includes an anode 4, an ionization chamber 3, and a sputtering electrode 9. The anode 4 is located at the top of the ionization chamber 3 and is powered to initiate an arc. The ionization chamber 3 provides space for the ionization of the introduced gas. The sputtering electrode 9 is located at the outlet of the ionization chamber 3 to generate a solid ion beam after being bombarded by gaseous ions.

[0025] The extraction system includes an interface flange 1, an insulating support 2, an extraction cavity, a ground electrode 11, and a suppression electrode 10. The interface flange 1 is connected to the extraction cavity. There is a potential difference between the anode 4 of the ionization chamber 3 and the ground electrode 11 of the extraction system, which allows the ion beam generated in the ionization chamber 3 to be transmitted backward. The insulating support 2 isolates the high voltage potential generated by the anode 4 from the ground potential generated by the ground electrode 11. The suppression electrode 10 prevents the returned electrons from interfering with the beam measurement at the Faraday tube at the rear end of the ion source.

[0026] This invention provides an ion source for a high-energy ion implanter. Because its components are mounted via connecting flanges, overall disassembly and installation are flexible and convenient. This allows for flexible selection of suitable source components for given charge materials, preferred ionization states, and extraction systems. Each source type can be easily adapted to new tasks by replacing individual components.

[0027] In this embodiment of the invention, the discharge chamber has a diameter of 80 mm and a length of 56 mm. In fact, these parameters can be adjusted according to specific needs. The discharge chamber includes an outer copper wall and an internal ionization space, such as... Figure 2As shown, eight Nd-Fe-B permanent magnets are arrayed on the circumference of the outer copper wall cross-section. The N and S poles of the permanent magnets are alternately arranged on the same circumference. The eight permanent magnets are evenly distributed along the circumference of the outer copper wall cross-section, with the magnetized surfaces pointing towards the center of the ionization chamber. This creates a longitudinal tangential magnetic field in the internal ionization space, used to confine primordial electrons and plasma. Four filaments 7, each made of 0.5mm diameter tantalum wire wound into a spring shape, are mounted on the cathode disk 8 of the discharge chamber. These four filaments 7 are connected in parallel and fixed to the cathode disk 8, located at the center of the tangential magnetic field generated by the eight permanent magnets. Electrons emitted from the filaments 7 precess in the tangential magnetic field, increasing the probability of collisions between electrons and gas, thus producing more ions.

[0028] The method of using the ion source described in this invention is as follows: In gas mode, no voltage is applied to the sputtering electrode. After gas is introduced through the gas inlet 5, electrons emitted by the energized filament 7 gain kinetic energy under the influence of the electric fields of the cathode and anode and collide with the gas, ionizing the gas into gaseous ions, i.e., generating non-metallic ions. In sputtering mode, a voltage is applied to the sputtering electrode. The gaseous ions that gain kinetic energy collide with the sputtering electrode 9, sputtering solid atoms and further ionizing them to generate solid particle ions, i.e., generating metallic ions. Under the action of the extraction system, the generated ions are extracted and transported backward.

[0029] As can be seen from the above embodiments, the ion source for high-energy ion implanters disclosed in this invention has broad application prospects. It is a multi-mode switchable ion source that, through modular design and a helical spring cathode structure, successfully solves the key problems of traditional ion sources, such as single function and difficult maintenance, and possesses the characteristics of high current and long lifespan. When gas is introduced, it can generate corresponding gaseous ions; additionally, by applying a sputtering voltage to the sputtering electrode, corresponding solid ions can be generated through gas ion collisions with the sputtering electrode, realizing flexible switching between gas mode and sputtering mode, significantly improving electron emission efficiency and beam stability. Experimental verification shows that the ion source for high-energy ion implanters disclosed in this invention exhibits excellent adaptability and performance in fields such as semiconductor doping, nuclear physics research, and space propulsion, possessing broad application potential. In the future, its applicability under extreme conditions can be further expanded through the integration of intelligent control systems and novel cathode materials, providing important support for the innovative development of ion source technology.

[0030] The device described in this invention is not limited to the embodiments described in the specific implementation. Other implementation methods derived by those skilled in the art based on the technical solution of this invention also fall within the scope of technical innovation of this invention.

Claims

1. An ion source for a high-energy ion implanter, wherein the ion source is used in the ion implanter, characterized in that: The ion source includes an inlet, a cathode, a discharge chamber, and an extraction system. The cathode is installed in the discharge chamber via a first connecting flange. One end of the discharge chamber is connected to the inlet via the first connecting flange, and the other end is connected to the extraction system via a second connecting flange. The inlet, the cathode, the central axis of the discharge chamber, and the central axis of the extraction system are all on the same straight line. The inlet is used to introduce gas. The cathode is used to emit electrons in the discharge chamber. In gas mode, the discharge chamber forms an electric field with the cathode, so that the electrons emitted by the cathode gain kinetic energy under the action of the electric field and collide with the introduced gas, ionizing the gas into gaseous ions. In sputtering mode, the gaseous ions collide with the sputtering electrodes in the discharge chamber to sputter solid atoms out and further ionize them to generate solid particle ions. The extraction system is used to extract the generated ions and transport them backward. The cathode includes a cathode tube, a filament, and a cathode disk. The air inlet is connected to the outer flange of the first connecting flange. One end of the cathode tube is installed on the inner flange of the first connecting flange, and the other end of the cathode tube is installed on the cathode disk. One end of the filament is fixed on the cathode disk and is evenly arranged around the cathode tube. The filament is in the shape of a spiral spring and is fixed in parallel on the cathode disk. The discharge chamber includes an anode, an ionization chamber, and a sputtering electrode. The anode is located at the top of the ionization chamber and is powered to initiate an arc. The ionization chamber provides space for the ionization of the introduced gas. The sputtering electrode is located at the outlet of the ionization chamber to generate a solid ion beam after being bombarded by gaseous ions. The discharge chamber includes an outer copper wall and an inner ionization space. Several permanent magnets are arrayed on the circumference of the outer copper wall in a direction parallel to the cathode tube. The N and S poles of the permanent magnets are arranged alternately on the same circumference. The several permanent magnets are evenly arranged along the circumference of the outer copper wall, with the magnetized surface pointing towards the center of the ionization chamber, forming a longitudinal tangential magnetic field in the inner ionization space.

2. The ion source for a high-energy ion implanter as described in claim 1, characterized in that: A reflective electrode is installed between the cathode tube and the inner flange of the first connecting flange.

3. An ion source for a high-energy ion implanter as described in claim 1, characterized in that: The filament is made of tantalum wire.

4. An ion source for a high-energy ion implanter as described in claim 1, characterized in that: The extraction system includes an interface flange, an insulating support, an extraction cavity, a ground electrode, and a suppression electrode. The interface flange is connected to the extraction cavity. There is a potential difference between the anode of the ionization chamber and the ground electrode of the extraction system, which allows the ion beam generated in the ionization chamber to be transmitted backward. The insulating support is used to isolate the high voltage potential generated by the anode from the ground potential generated by the ground electrode. The suppression electrode is used to prevent the returned electrons from interfering with the beam measurement at the Faraday tube at the rear end of the ion source.

5. An ion source for a high-energy ion implanter as described in claim 1, characterized in that: The permanent magnet is an Nd-Fe-B permanent magnet.

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