Superconducting thin film and preparation process equipment thereof

Abstract

The invention provides a superconducting thin film and preparation process equipment thereof. In the process equipment, a sputtering system and a substrate system are opposite up and down in a reaction chamber; the working gas inlet channel is located at the position, close to the target, of the shell of the reaction chamber, the reaction gas inlet channel is located at the position, close to the substrate system, of the shell of the reaction chamber, and the exhaust port is located in the shell of the side wall of the reaction chamber. The reaction gas inlet channel is arranged to be far away from the target material, the target poisoning phenomenon is avoided, and the magnetron sputtering efficiency and the superconducting thin film deposition rate are improved; meanwhile, the working gas inlet channel is arranged close to the target material, so that plasmas generated by the target material are more stable, and the critical temperature and the critical current density of the superconducting thin film material are enhanced; in addition, the reaction gas inlet channel is higher than the substrate, reaction products are prevented from depositing on the surface of the gas inlet channel, and the deposition rate of the superconducting film is improved. And finally, a working gas inlet channel is arranged to be lower than the target material, so that target material atoms are prevented from being sputtered by bombardment on the surface of the gas inlet channel to pollute the reaction chamber and the superconducting film.

Description

Technical Field

[0001] The present invention belongs to the technical field of semiconductor integrated circuit manufacturing, and in particular relates to a superconducting film and a preparation process equipment thereof. Background Art

[0002] In recent years, NbTiN thin films, as a superconducting material, have been widely used in superconducting devices such as superconducting nanowire single-photon detectors (SNSPDs), hot electron bolometers (Hot Electron Bolometer), and superconductor-insulator-superconductor (SIS) due to their low resistivity (ρ), high critical temperature (Tc), high critical current density (Jc), and high critical magnetic field (Bc2).

[0003] Magnetron reactive sputtering deposition is a commonly used process for preparing NbTiN thin films. Previous studies have shown that this process can be used to prepare high-Tc δ-NbTiN thin films at room temperature. However, the quality of Nb(Ti)N superconducting thin films prepared using conventional reactive magnetron sputtering technology is highly dependent on the substrate type. High-quality Nb(Ti)N superconducting thin films can only be deposited on substrates with low lattice mismatch, such as MgO. Therefore, depositing high-quality Nb(Ti)N on any flat, lattice-free surface is crucial for developing ultra-low-temperature superconducting transmission lines and applications such as high-sensitivity antennas, resonators, filters, and delay lines. Furthermore, because contact between the reactive gas and the target surface is difficult to avoid during conventional reactive sputtering, target poisoning can occur during film preparation. This can alter the target surface composition, reducing the deposition rate and affecting the composition of the resulting film. This further hinders the stable preparation of high-performance thin films using this process.

[0004] Therefore, there is an urgent need for a structure or method that can improve the deposition quality, deposition rate and applicable range of substrate materials of superconducting thin films.

[0005] It should be noted that the above introduction to the technical background is only for the convenience of providing a clear and complete description of the technical solutions of this application and for the convenience of understanding by those skilled in the art. It cannot be considered that the above technical solutions are well known to those skilled in the art simply because these solutions are explained in the background technology part of this application. Summary of the Invention

[0006] In view of the above shortcomings of the prior art, the object of the present invention is to provide a superconducting film and a preparation process equipment thereof, so as to solve the problems of poor quality and low preparation rate of superconducting films deposited by magnetron reactive sputtering in the prior art.

[0007] To achieve the above-mentioned object, the present invention provides a superconducting thin film preparation process equipment, the process equipment comprising: a reaction chamber, a sputtering system, a substrate system and a gas control system; the sputtering system and the substrate system are located opposite each other in the reaction chamber, and the gas control system is located in the shell of the reaction chamber;

[0008] The sputtering system includes a magnetic field generating structure, a target material, a magnetron sputtering cathode, and a magnetron sputtering anode; the magnetic field generating structure surrounds the end of the magnetron sputtering cathode extending into the reaction chamber, and the target material is fixed to the end surface of the magnetron sputtering cathode extending into the reaction chamber;

[0009] The substrate system includes a substrate clamp and a substrate heating system, wherein the substrate clamp is used to clamp the substrate on which the superconducting thin film is to be provided, and the substrate heating system is used to heat the substrate;

[0010] The gas control system includes a working gas inlet channel, a reaction gas inlet channel and an exhaust port. The working gas inlet channel is located in the shell of the reaction chamber close to the target material, the reaction gas inlet channel is located in the shell of the reaction chamber close to the substrate system, and the exhaust port is located in the shell of the side wall of the reaction chamber.

[0011] Optionally, the substrate system is located at the top of the reaction chamber, and the magnetic field generating structure, the target material and the magnetron sputtering cathode are all located at the bottom of the reaction chamber.

[0012] Optionally, the reaction gas inlet channel is located in a shell at the top of the reaction chamber, and the working gas inlet channel is located in a shell at the bottom of the reaction chamber.

[0013] Optionally, a gas inlet port of the reaction gas inlet channel extending into the reaction chamber is higher than the substrate clamped by the substrate clamp.

[0014] Optionally, the working gas inlet channel extends into the reaction chamber at an inlet port lower than the position of the target material.

[0015] Optionally, the magnetron sputtering anode is located in the reaction chamber near the substrate system.

[0016] Optionally, the sputtering system includes two or more magnetron sputtering cathodes, each of which is evenly distributed around the central axis of the substrate fixture, and one end of each magnetron sputtering cathode for fixing the target material is oriented toward the center point of the substrate fixture.

[0017] Optionally, the gas control system includes the same number of working gas inlet channels as the magnetron sputtering cathodes, and each of the working gas inlet channels extends in the same direction as one end of a fixed target of the magnetron sputtering cathode.

[0018] Optionally, the reaction gas inlet channel is used to input nitrogen, the working gas inlet channel is used to input argon, the target material includes a Nb target and a Ti target, and the superconducting film preparation process equipment is used to prepare NbTiN superconducting film on a substrate.

[0019] The present invention also provides a superconducting film, which is prepared by using any one of the above-mentioned superconducting film preparation process equipment.

[0020] As described above, the superconducting film and the manufacturing process equipment thereof of the present invention have the following beneficial effects:

[0021] The present invention avoids target poisoning caused by the generation of a large amount of nitride on the target by arranging the reaction gas inlet channel away from the target material, thereby greatly improving the magnetron sputtering efficiency and the deposition rate of the superconducting film, and improving the quality and performance of the obtained superconducting film;

[0022] The present invention arranges the working gas inlet channel near the target material, so that the plasma generated near the target material is more stable, and can be ignited and maintained at a lower gas pressure, which can further enhance the critical temperature and critical current density of the superconducting thin film material;

[0023] The present invention prevents reaction products from being deposited on the surface of the inlet channel and affecting the deposition rate of the superconducting film by setting the height relationship between the reaction gas inlet channel and the substrate;

[0024] The present invention sets a height relationship between the working gas inlet channel and the target material to prevent the surface of the working gas inlet channel from being bombarded by accelerated electrons, secondary electrons and working gas ions and sputtering atoms on the surface of the working gas inlet channel, thereby reducing contamination of the reaction chamber and the superconducting film. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 The figure shows the internal structure of a process equipment for depositing superconducting thin films by magnetron sputtering in the prior art during the deposition process.

[0026] Figure 2A schematic diagram of the structure of the superconducting thin film preparation process equipment in Example 1 of the present application is shown.

[0027] Figure 3 A fitting curve diagram of the normalized resistance of the superconducting thin film obtained by the superconducting thin film preparation process equipment in Example 1 of the present application on different substrates near the critical temperature with respect to temperature is shown.

[0028] Figure 4 A critical temperature distribution point diagram of the superconducting thin film obtained by the superconducting thin film preparation process equipment in Example 1 of the present application on different substrates through fitting calculation of the normalized resistance is shown.

[0029] BRIEF DESCRIPTION OF DRAWINGS

[0030] 10, reaction chamber; 11, housing;

[0031] 21, magnetic field generating structure; 22, target material; 23, magnetron sputtering cathode; 24, direct current source;

[0032] 31, substrate clamp; 32, substrate heating system; 33, substrate; 34, tray rotating shaft;

[0033] 41, working gas inlet channel; 42, reaction gas inlet channel; 43, exhaust port; 44, gas inlet; 45, valve;

[0034] 51, superconducting thin film / NbTiN; 52, reaction gas / nitrogen; 53, working gas / argon; 54, plasma; 55, Nb atom; 56, Ti atom; 57, TiN molecule; 58, NbN molecule;

[0035] 61, N ion; 62, Ar ion. DETAILED DESCRIPTION

[0036] The embodiments of the present application will be described in detail by specific examples, and those skilled in the art can easily understand other advantages and effects of the present application from the disclosure. The present application can also be implemented or applied by other different embodiments, and various modifications or changes can be made to the details in the specification based on different views and applications without departing from the spirit of the present application.

[0037] As in the detailed description of the embodiments of the present application, the schematic diagrams showing the structure of the device are partially enlarged without the general scale for the convenience of description, and the schematic diagrams are only examples, which should not limit the scope of protection of the present application. In addition, three-dimensional spatial dimensions including length, width and depth should be included in actual production.

[0038] For convenience of description, spatially relative terms such as "under," "below," "below," "below," "above," and "upper" may be used herein to describe the relationship of one element or feature to other elements or features shown in the drawings. It will be understood that these spatially relative terms are intended to encompass other orientations of the device in use or operation in addition to the orientation depicted in the drawings.

[0039] In the context of the present application, a structure described as a first feature being "above" a second feature may include embodiments where the first and second features are in direct contact, and may also include embodiments where additional features are formed between the first and second features, such that the first and second features may not be in direct contact.

[0040] It should be noted that the diagrams provided in this embodiment are only used to schematically illustrate the basic concept of the present invention. Therefore, the diagrams only show components related to the present invention rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component can be changed at will, and the component layout type may also be more complex. The quantity range given in the present invention defaults to including the two boundary values ​​of the quantity range without special restrictions.

[0041] In the prior art, during the process of magnetron reactive sputtering deposition of the NbTiN superconducting film 51, as shown in FIG. Figure 1 As shown, a mixed gas of nitrogen as a reaction gas 52 and argon as a working gas 53 is input into the reaction chamber 10 through a gas inlet 44 located on the side wall shell 11 of the reaction chamber 10 . The mixed gas collides with the accelerated electrons under the action of the electric field, ionizing a large number of Ar ions 62, N ions 61 and new secondary electrons. The ions are accelerated under the action of the electric field to bombard the target material 22, sputtering out neutral target material atoms, which combine with N atoms to form nitride TiN molecules 57 and NbN molecules 58, and are deposited on the substrate to form a superconducting thin film 51. At the same time, a large number of secondary electrons are bound to the surface of the target material 22 by the magnetic field. Under the combined action of the circular magnetic field and the electric field, they move in a circular motion on the surface of the target material 22, thereby further ionizing a large number of Ar ions 62 to bombard the target material 22, thereby increasing the deposition rate of the superconducting thin film 51. In this process, nitrogen will also directly contact the surface of the target material 22, and chemically react with the target material 22 under the combined action of the bombardment of the Ar ions 62 and the temperature of the target material 22, thereby forming a layer of nitride on the surface of the target material 22.

[0042] Ideally, the nitride formed on the surface of the target 22 is bombarded by ions to be stripped off the surface of the target 22, thereby exposing the surface of the target 22 to form the nitride again, and the cycle is repeated. However, when the amount of the reaction gas 52 is too large, the generation rate of the nitride on the surface of the target 22 is greater than the stripping rate, which deepens the target poisoning phenomenon, thereby reducing the sputtering reaction efficiency and affecting the composition of the superconducting thin film 51, so that the performance of the thin film changes, which is difficult to meet the performance requirements of the superconducting thin film 51.

[0043] The application provides a superconducting thin film preparation process equipment, such as Figure 2 As shown in the figure, the process equipment comprises a reaction chamber 10, a sputtering system, a substrate system and a gas control system; the sputtering system and the substrate system are opposite to each other in the reaction chamber 10, and the gas control system is located in the shell 11 of the reaction chamber 10.

[0044] The sputtering system comprises a magnetic field generating structure 21, a target 22, a magnetron sputtering cathode 23 and a magnetron sputtering anode; the magnetic field generating structure 21 surrounds the end of the magnetron sputtering cathode 23 extending into the reaction chamber 10, and the target 22 is fixed to the surface of the end of the magnetron sputtering cathode 23 extending into the reaction chamber 10.

[0045] The substrate system comprises a substrate clamp 31 and a substrate heating system 32, the substrate clamp 31 is used for clamping a substrate 33 to be provided with a superconducting thin film 51, and the substrate heating system 32 is used for heating the substrate 33.

[0046] The gas control system comprises a working gas inlet channel 41, a reaction gas inlet channel 42 and an exhaust port 43; the working gas inlet channel 41 is located at the position close to the target 22 of the shell 11 of the reaction chamber 10, the reaction gas inlet channel 42 is located at the position close to the substrate system of the shell 11 of the reaction chamber 10, and the exhaust port 43 is located at the shell 11 of the side wall of the reaction chamber 10.

[0047] The present invention arranges the sputtering system and the substrate system in the reaction chamber 10 so that they are opposite to each other in the upper and lower parts, and arranges the reaction gas inlet channel 42 at a position close to the substrate system and the working gas inlet channel 41 at a position close to the target material 22, thereby maximizing the distance between the reaction gas 52 and the target material 22, avoiding the target poisoning phenomenon caused by the generation of a large amount of nitride on the target material 22 due to excessive flow of the reaction gas 52, thereby greatly improving the magnetron sputtering efficiency and the deposition rate of the superconducting film 51, and improving the quality and performance of the obtained superconducting film 51; at the same time, when the quality of the superconducting film 51 is better, its uniformity, The composition, thickness and other properties are relatively stable, so that the superconducting film 51 is less affected by the lattice mismatch between the superconducting film 51 and the substrate 33. The substrate 33 materials suitable for the superconducting film 51 can be expanded, and the flexibility of selecting the substrate 33 of the superconducting film 51 is improved, especially the substrate 33 materials with similar properties to the NbTiN film; in addition, by arranging the working gas inlet channel 41 near the target material 22, the plasma generated near the target material 22 is more stable, and can be ignited and maintained at a lower gas pressure. The critical temperature and critical current density of the superconducting film 51 material can be further enhanced.

[0048] Specifically, the working gas inlet channel 41 and the reaction gas inlet channel 42 in the present invention can be channels originally provided in the original reaction chamber 10, and can be directly provided by controlling the opening of the channels; or they can be channels additionally provided in the reaction chamber 10 to meet the requirements; Figure 2 As shown, when magnetron sputtering deposition of the superconducting film 51 is performed simultaneously, the valve 45 of the gas inlet 44 located on the side wall of the original reaction chamber 10 needs to be closed to prevent the entry of irrelevant external gas.

[0049] Specifically, if Figure 2 As shown, the exhaust port 43 of the reaction chamber 10 is also provided with a valve 45. The exhaust port 43 of the reaction chamber 10 is connected to a vacuum pump (not shown in the figure) to extract additional gas as needed to ensure that the reaction rate in the reaction chamber 10 meets the requirements.

[0050] In one embodiment, the tray shaft 34 is connected to the substrate fixture 31 to control the substrate 33 to rotate at a constant speed during the magnetron sputtering process, so that the superconducting thin film 51 obtained on the substrate 33 is deposited uniformly.

[0051] Specifically, the magnetron sputtering cathode 23 is connected to a DC source 24 outside the shell 11 of the reaction chamber 10 to generate glow discharge.

[0052] In one embodiment, Figure 2As shown, the substrate system is located at the top of the reaction chamber 10 , and the magnetic field generating structure 21 , the target material 22 and the magnetron sputtering cathode 23 are all located at the bottom of the reaction chamber 10 .

[0053] The present invention arranges the substrate system at the top and the magnetic field generating structure 21, the target material 22 and the magnetron sputtering cathode 23 at the bottom, so that the movement trajectory of the sputtered particles during the deposition process from the surface of the target material 22 to the substrate 33 is relatively simple, especially when coating a large area substrate 33, the uniformity of the film thickness can be better controlled.

[0054] In one embodiment, Figure 2 As shown, the reaction gas inlet channel 42 is located in the shell 11 at the top of the reaction chamber 10 , and the working gas inlet channel 41 is located in the shell 11 at the bottom of the reaction chamber 10 .

[0055] The present invention arranges the reaction gas inlet channel 42 in the shell 11 at the top of the reaction chamber 10, and the working gas inlet channel 41 is located in the shell 11 at the bottom of the reaction chamber 10, so that the reaction gas 52 is close to the substrate 33 and the working gas 53 is close to the target material 22. At the same time, by adjusting the input directions of the reaction gas 52 and the working gas 53 to face each other, the efficiency of depositing the superconducting film 51 can be further improved.

[0056] In one embodiment, Figure 2 As shown, the gas inlet port 44 of the reaction gas inlet channel 42 extending into the reaction chamber 10 is higher than the substrate 33 clamped by the substrate clamp.

[0057] The present invention prevents reaction products from being deposited on the surface of the inlet channel and affecting the deposition rate of the superconducting thin film 51 by setting a height relationship between the reaction gas inlet channel 42 and the substrate 33. At the same time, after the reaction gas 52 enters the reaction gas inlet channel 42, since its position is higher than the substrate 33, it fully contacts and reacts with the target atoms of the magnetron sputtering during the sinking process, which can increase the chance of collision reaction between the reaction gas 52 and the target atoms and improve the reaction utilization rate of nitrogen. Moreover, the reaction gas inlet channel 42 higher than the substrate 33 helps to establish a relatively uniform concentration field of the reaction gas 52, which is conducive to forming uniform reaction products on the surface of the substrate 33, making the composition and structure of the formed superconducting thin film 51 more uniform, and improving the quality and performance of the film.

[0058] In one embodiment, Figure 2 As shown, the gas inlet port 44 of the working gas inlet channel 41 extending into the reaction chamber 10 is lower than the position of the target 22 .

[0059] The present invention arranges the working gas inlet channel 41 below the target material 22 to prevent the working gas inlet channel 41 from being located on the moving path of the sputtered particles and contacting the plasma 54, thereby preventing the surface of the working gas inlet channel 41 from being bombarded by accelerated electrons, secondary electrons and working gas 53 ions and sputtering atoms from the surface of the working gas inlet channel 41, thereby reducing contamination of the reaction chamber 10 and the superconducting film 51 and improving the service life of the working gas inlet channel 41; at the same time, a high-concentration area can be formed near the target material 22, thereby increasing the probability of collision between the working gas 53 and the surface of the target material 22, and enhancing the bombardment effect of the working gas 53 ions on the target material 22, thereby improving the sputtering efficiency of the target material 22 and improving the deposition rate of the thin film.

[0060] Specifically, the distance between the working gas inlet channel 41 and the target material 22 needs to be set according to actual applications to ensure that the introduction position of the working gas 53 is close to the target material 22 and away from the substrate, while avoiding the working gas 53 being too close to the surface of the target material 22, sputtering atoms on the surface of the working gas inlet channel 41, and contaminating the reaction chamber 10 and the superconducting film 51 obtained by magnetron sputtering.

[0061] In one embodiment, the substrate system is located at the bottom of the reaction chamber 10 , and the magnetic field generating structure 21 , the target material 22 , and the magnetron sputtering cathode 23 are all located at the top of the reaction chamber 10 .

[0062] The present invention arranges the substrate system at the bottom and the magnetic field generating structure 21, target material 22 and magnetron sputtering cathode 23 at the top, so that when the sputtered particles are sputtered downward from the target material 22 to the substrate 33, the particles are subjected to relatively few collisions during the flight process and can maintain a higher energy, thereby better ensuring the performance of the film, forming a denser structure on the substrate 33, and improving the hardness and wear resistance of the deposited film.

[0063] In one embodiment, the magnetron sputtering anode (not shown) is located in the reaction chamber 10 near the substrate system.

[0064] The present invention increases the electric field strength E near the substrate 33 by setting the magnetron sputtering anode close to the substrate system, which helps to accelerate the ions (such as argon ions) in the plasma to move toward the surface of the substrate 33, thereby enhancing the ion bombardment effect; ion bombardment can clean the surface of the substrate 33, remove surface pollutants and oxides, provide a cleaner surface for the deposition of the film, and help improve the adhesion between the formed superconducting film 51 and the substrate 33; in addition, ion bombardment can also cause a certain degree of roughening of the surface of the substrate 33, increase the adhesion area of ​​the film, and further improve the adhesion; at the same time, the enhanced ion bombardment near the substrate 33 can also provide additional energy for the growth of the superconducting film 51, thereby making it easier for the material of the superconducting film 51 to migrate and rearrange on the surface of the substrate 33, forming a denser and more uniform film structure, thereby improving the performance of the film. Specifically, the magnetron sputtering anode can also be set at other suitable positions as needed, all within the scope of protection of the present invention.

[0065] In one embodiment, the reaction gas inlet passage 42 is used to input nitrogen, the working gas inlet passage 41 is used to input argon, the target material 22 includes a Nb target and a Ti target, and the superconducting thin film 51 preparation process apparatus is used to prepare a NbTiN superconducting thin film 51 on a substrate 33. Specifically, the present invention is primarily used to address target poisoning caused by the formation of nitrides on the target material 22 during the formation of the NbTiN superconducting thin film 51. However, it can also be applied to other target poisoning issues caused by reaction products deposited on the surface of the target material 22 being difficult to bombard the thin film due to excessive reaction gas 52 during magnetron sputtering deposition, and all such issues fall within the scope of protection of the present invention.

[0066] Specifically, if Figure 2As shown, when forming the NbTiN superconducting film 51, argon gas is passed through the working gas inlet channel 41 to the vicinity of the Ti target 22 and the Nb target 22, where it is used to ionize and generate plasma 54, which then bombards the target 22 to produce target atoms Nb atoms 55 and Ti atoms 56; nitrogen gas is passed through the reaction gas inlet channel 42 to the vicinity of the substrate 33. When the target atoms approach the substrate 33, they come into contact with the nitrogen gas and react to form nitride TiN 57 molecules and NbN molecules 58, which are ultimately deposited on the substrate 33 to form the NbTiN solid solution superconducting film 51. Because the nitrogen source is far away from the target 22, no large amount of nitride will be generated on the surface of the target 22, thereby effectively avoiding the occurrence of target poisoning. For a reaction chamber 10 originally equipped with the inlet channel position requirements of this solution, this process only requires controlling the gas path of the equipment to achieve this, without the need for equipment adjustment, and has a significant effect on avoiding target poisoning and improving process stability. Because only argon gas is introduced near the target 22, the plasma near the target gun is more stable. The target gun can ignite and maintain a stable plasma at a lower pressure, further enhancing the critical temperature and critical current density of the NbTiN superconducting film 51. Furthermore, due to the significantly reduced nitrogen ion concentration near the surface of the target 22, the deposition rate of the NbTiN film is increased. Measurements have shown that the deposition rate is more than twice that of conventional deposition techniques.

[0067] In one embodiment, the sputtering system includes a magnetron sputtering cathode 23 , which passes through the central axis of the substrate fixture 31 . The magnetron sputtering cathode 23 fixes one end of the target 22 toward the center point of the substrate fixture 31 .

[0068] Specifically, when forming the NbTiN superconducting thin film 51 and providing a magnetron sputtering cathode 23 , the target material 22 on the magnetron sputtering cathode 23 is an alloy target material 22 of Nb and Ti.

[0069] In one embodiment, the sputtering system includes two or more magnetron sputtering cathodes 23, and each of the magnetron sputtering cathodes 23 is evenly distributed around the central axis of the substrate fixture 31, and one end of each magnetron sputtering cathode 23 that fixes the target material 22 is facing the center point of the substrate fixture 31.

[0070] The present invention arranges multiple magnetron sputtering cathodes 23 in a confocal arrangement to perform confocal magnetron sputtering, which can accurately control and customize the coating composition of the target material 22 and achieve a variety of coating characteristics; at the same time, the substrate 33 can be rotated in the system, and magnetron sputtering deposition can be performed at a certain angle by a smaller sputtering source, so that the thickness of the obtained superconducting film 51 is more uniform at all locations; and more thin film material can be deposited per unit time, thereby improving production efficiency and shortening the preparation cycle.

[0071] Specifically, if Figure 2 As shown, when a NbTiN superconducting thin film 51 is formed and two magnetron sputtering cathodes 23 are provided, the targets 22 on the two magnetron sputtering cathodes 23 are a Nb target 22 and a Ti target 22 respectively.

[0072] Specifically, when a NbTiN superconducting film 51 is formed and more than two magnetron sputtering cathodes 23 are set, the targets 22 on the magnetron sputtering cathodes 23 are respectively Nb targets 22 and Ti targets 22, and the number of Nb targets 22 and Ti targets 22 is adjusted according to the composition of the obtained superconducting film 51 so that it can better meet the requirements for the composition of the superconducting film 51.

[0073] In one embodiment, Figure 2 As shown, the gas control system includes the same number of working gas inlet channels 41 as the magnetron sputtering cathodes 23 , and each of the working gas inlet channels 41 extends in the same direction as one end of the magnetron sputtering cathode 23 fixing the target 22 .

[0074] The present invention sets a working gas inlet channel 41 corresponding to the same extension direction as the target material 22 near each magnetron sputtering cathode 23, so that during magnetron sputtering, the gas molecules of the working gas 53 can be more evenly distributed around the cathode, thereby improving the gas utilization efficiency and reducing gas waste, while ensuring that the generation of plasma is more stable and a more uniform plasma distribution is formed, ensuring that the surface of the target material 22 is uniformly bombarded by ions, improving the uniformity of the sputtering rate, and thus making the thickness and composition of the film more uniform; in addition, the gas flow path of the working gas 53 is consistent with the direction of the sputtering process, reducing the eddy current and unevenness of the gas flow during the sputtering process, thereby improving the stability and efficiency of the sputtering process, improving the microstructure of the film, and improving the density and adhesion of the film, thereby improving the overall quality and performance of the film; and the uniform gas distribution and plasma density help to reduce uneven wear on the surface of the target material 22 and extend the service life of the target material 22.

[0075] In one embodiment, an MPS-6000 ultra-high vacuum magnetron sputtering device is used to simultaneously deposit NbTiN thin films on different substrates. The process parameters are as follows: Nb target power 125W, Ti target power 100W, and the thickness of the formed NbTiN thin films is about 300nm. The substrate 33 materials selected in this embodiment include single crystal Si substrate (100), SiO2 / Si substrate prepared by LPCVD (Low Pressure Chemical Vapor Deposition), commercial microscope slides, MgO <100> MgO <110> and MgO <111> , where MgO is the substrate grown along different crystal directions. After the deposition is completed, the PPMS (Physical Property Measurement System) is used to measure the change of the normalized resistance of the NbTiN film formed on different substrate materials near the critical temperature with the temperature using the four-wire method, and the following is obtained: Figure 3 The data points in the 3D superconducting material are fitted to the measured data obtained from this physical process using the fluctuation conductivity of the 3D superconducting material. The specific fitting formula is: in, represents the normal conductivity of the bulk material, represents the fluctuation conductivity σ of the three-dimensional superconducting material s , the constant C is: represents the normalized Planck constant, ξ(0) represents the superconducting coherence length, and e represents the unit electron charge. According to the fitting formula, we can get Figure 3 The fitting line shown as the solid line in the figure is used to obtain the critical temperature of the NbTiN film on different substrates 33 under zero field, as shown in FIG. Figure 4 As shown, the critical temperatures are all around 14K, the maximum difference is 0.752K, the average is 14.159K, and the deviation from the average is only 5.3%, indicating that the superconducting film 51 preparation process equipment of the present invention can stably prepare NbTiN films with high Tc and excellent performance on different substrate 33 materials.

[0076] The present invention further provides a superconducting film 51 , which is prepared using any of the above-mentioned superconducting film 51 preparation process equipments.

[0077] In summary, the superconducting thin film and the preparation process equipment thereof can avoid the target poisoning phenomenon caused by a large amount of nitride generated on the target material by setting the reaction gas inlet channel away from the target material, thereby greatly improving the magnetron sputtering efficiency and the deposition rate of the superconducting thin film, and improving the quality and performance of the obtained superconducting thin film. At the same time, by setting the working gas inlet channel near the target material, the plasma generated near the target material is more stable, can be ignited at a lower gas pressure and maintain a stable plasma, and can further enhance the critical temperature and critical current density of the superconducting thin film material. In addition, by setting the height relationship between the reaction gas inlet channel and the substrate, the deposition of the reaction product on the surface of the inlet channel is avoided, and the deposition rate of the superconducting thin film is not affected. Finally, by setting the height relationship between the working gas inlet channel and the target material, the surface of the working gas inlet channel is prevented from being bombarded by accelerated electrons, secondary electrons and working gas ions to sputter atoms on the surface of the working gas inlet channel, thereby reducing the pollution of the reaction chamber and the superconducting thin film.

[0078] Therefore, the present application effectively overcomes the shortcomings of the prior art and has high industrial utilization value.

[0079] The above embodiments only exemplarily illustrate the principles and effects of the present application, and are not used to limit the present application. Any person skilled in the art can modify or change the above embodiments without departing from the spirit and scope of the present application. Therefore, all equivalent modifications or changes completed by those skilled in the art without departing from the spirit and technical thought disclosed by the present application should be covered by the claims of the present application.

Claims

1. A superconducting thin film preparation process equipment, characterized in that: The process equipment includes: a reaction chamber, a sputtering system, a substrate system and a gas control system; the sputtering system and the substrate system are opposite to each other in the reaction chamber, and the gas control system is located in the shell of the reaction chamber; The sputtering system includes a magnetic field generating structure, a target material, a magnetron sputtering cathode, and a magnetron sputtering anode; the magnetic field generating structure surrounds the end of the magnetron sputtering cathode extending into the reaction chamber, and the target material is fixed to the end surface of the magnetron sputtering cathode extending into the reaction chamber; The substrate system includes a substrate clamp and a substrate heating system, wherein the substrate clamp is used to clamp the substrate on which the superconducting thin film is to be provided, and the substrate heating system is used to heat the substrate; The gas control system includes a working gas inlet channel, a reaction gas inlet channel and an exhaust port. The working gas inlet channel is located in the shell of the reaction chamber close to the target material, the reaction gas inlet channel is located in the shell of the reaction chamber close to the substrate system, and the exhaust port is located in the shell of the side wall of the reaction chamber.

2. The superconducting thin film preparation process equipment according to claim 1, characterized in that: The substrate system is located at the top of the reaction chamber, and the magnetic field generating structure, the target material and the magnetron sputtering cathode are all located at the bottom of the reaction chamber.

3. The superconducting thin film preparation process equipment according to claim 2, characterized in that: The reaction gas inlet channel is located at a shell at the top of the reaction chamber, and the working gas inlet channel is located at a shell at the bottom of the reaction chamber.

4. The superconducting thin film preparation process equipment according to claim 2, characterized in that: The gas inlet port of the reaction gas inlet channel extending into the reaction chamber is higher than the base clamped by the substrate clamp.

5. The superconducting thin film preparation process equipment according to claim 2, characterized in that: The gas inlet of the working gas inlet channel extending into the reaction chamber is located below the position of the target.

6. The superconducting thin film preparation process equipment according to any one of claims 1 to 5, characterized in that: The magnetron sputtering anode is located in the reaction chamber near the substrate system.

7. The superconducting thin film preparation process equipment according to any one of claims 1 to 5, characterized in that: The sputtering system includes two or more magnetron sputtering cathodes, each of which is evenly distributed around the central axis of the substrate fixture, and one end of each magnetron sputtering cathode for fixing the target material faces the center point of the substrate fixture.

8. The superconducting thin film preparation process equipment according to claim 7, characterized in that: The gas control system includes the same number of working gas inlet channels as the magnetron sputtering cathodes, and each of the working gas inlet channels extends in the same direction as one end of a fixed target of the magnetron sputtering cathode.

9. The superconducting thin film preparation process equipment according to claim 1, characterized in that: The reaction gas inlet channel is used to input nitrogen, the working gas inlet channel is used to input argon, the target materials include Nb target and Ti target, and the superconducting film prepared by the superconducting film preparation process equipment on the substrate is NbTiN.

10. A superconducting film, characterized in that: The superconducting film is prepared by using the superconducting film preparation process equipment described in any one of claims 1 to 9.

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