Superconducting film preparation method, superconducting film, quantum device and quantum chip

Abstract

The present invention discloses a method for preparing a superconducting film, a superconducting film, a quantum device and a quantum chip. The method comprises: raising the first atmosphere environment where the first superconducting film is located from the first temperature to the second temperature, so that the first superconducting film is in the second atmosphere environment, wherein the first superconducting film is a superconducting material deposited on a substrate; after the second atmosphere environment reaches the second temperature, hydrogen atoms are continuously introduced into the second atmosphere environment and maintained for a predetermined time, so that the first superconducting film is in a third atmosphere environment, so that hydrogen atoms fill the crystal structure defects on the microscopic scale of the first superconducting film, wherein the second temperature is used to maintain the free state of hydrogen atoms; after the predetermined time, the temperature of the third atmosphere environment is reduced from the second temperature to the third temperature, and a second superconducting film is prepared, wherein the third temperature is lower than the first temperature. The present invention solves the technical problem that the dynamic inductance of the superconducting film used in the quantum circuit is not high enough.

Description

Technical Field

[0001] The present invention relates to the field of materials, and in particular to a method for preparing a superconducting film, a superconducting film, a quantum device and a quantum chip. Background Art

[0002] The integration of quantum circuits will significantly affect their application prospects. How to integrate more quantum components on the same area is a practical problem faced by the field of quantum chips. In related technologies, in order to improve the integration of quantum circuits, the following solutions have been proposed: adjusting the thickness of the superconducting film in the circuit, changing the chemical composition of the superconducting film, and adjusting the deposition conditions of the superconducting film on the substrate. However, although the above solutions can increase the integration of quantum circuits by increasing the dynamic inductance of the superconducting film, they will have other adverse effects on the quantum circuit, such as reducing the quality factor Q of the circuit, affecting the chemical ratio of the film, and affecting other basic physical parameters of the film.

[0003] To address the above-mentioned problems, no effective solution has been proposed yet. Summary of the invention

[0004] The embodiments of the present invention provide a method for preparing a superconducting film, a superconducting film, a quantum device and a quantum chip, so as to at least solve the technical problem that the dynamic inductance of the superconducting film used in the sub-circuit is insufficient.

[0005] According to one aspect of an embodiment of the present invention, a method for preparing a superconducting film is provided, comprising: raising a first atmosphere environment in which a first superconducting film is located from a first temperature to a second temperature, so that the first superconducting film is in a second atmosphere environment, wherein the first superconducting film is a superconducting material deposited on a substrate; after the second atmosphere environment reaches the second temperature, continuously introducing hydrogen atoms into the second atmosphere environment and maintaining the temperature for a predetermined period of time, so that the first superconducting film is in a third atmosphere environment, so that the hydrogen atoms fill in the crystal structure defects on a microscopic scale of the first superconducting film, wherein the second temperature is used to maintain the free state of the hydrogen atoms; after the predetermined period of time, lowering the temperature of the third atmosphere environment from the second temperature to a third temperature, so as to prepare a second superconducting film, wherein the third temperature is lower than the first temperature.

[0006] Optionally, continuously introducing hydrogen atoms into the second atmosphere and maintaining it for a predetermined period of time includes: continuously introducing a hydrogen-containing gas into the second atmosphere so that the hydrogen-containing gas decomposes at the second temperature to release the hydrogen atoms in a free state, so that the hydrogen atoms fill the crystal structure defects on a microscopic scale of the first superconducting film, wherein the second temperature is not lower than the decomposition temperature of the hydrogen-containing gas.

[0007] Optionally, the chemical element species of the first superconducting film include the chemical element species of the hydrogen-containing gas.

[0008] Optionally, the first superconducting film includes: nitrogen-based superconducting material.

[0009] Optionally, the nitrogen-based superconducting material includes any one of the following: titanium nitride, aluminum nitride, and gallium nitride.

[0010] Optionally, the hydrogen-containing gas includes: nitrogen hydrogen compounds.

[0011] Optionally, the nitrogen hydrogen compound includes ammonia, and the second temperature is not less than 400 degrees Celsius.

[0012] Optionally, the first superconducting film includes: phosphorus-based superconducting material.

[0013] Optionally, the hydrogen-containing gas includes: phosphorus hydrogen compounds.

[0014] Optionally, the phosphorus hydrogen compound includes PH3, and the second temperature is not less than 500 degrees Celsius.

[0015] Optionally, the flow rate of the hydrogen-containing gas continuously introduced into the second atmosphere environment is not less than 50 sccm.

[0016] Optionally, the predetermined duration is not less than 600 seconds.

[0017] Optionally, raising the first atmosphere in which the first superconducting film is located from the first temperature to the second temperature includes: continuously introducing a first inert gas into the first atmosphere, and raising the first atmosphere from the first temperature to the second temperature while continuously introducing the first inert gas; lowering the temperature of the third atmosphere from the second temperature to the third temperature includes: continuously introducing a second inert gas into the third atmosphere, and lowering the third atmosphere from the second temperature to the third temperature while continuously introducing the second inert gas.

[0018] Optionally, a flow rate of the first inert gas introduced into the first atmosphere is not less than 3000 sccm, and a flow rate of the second inert gas introduced into the third atmosphere is not less than 3000 sccm.

[0019] According to another aspect of an embodiment of the present invention, a superconducting film is further provided. The superconducting film is prepared by any one of the above methods.

[0020] According to another aspect of the embodiments of the present invention, there is provided a microwave component, comprising: a substrate and the above-mentioned superconducting film, wherein the superconducting film is deposited on the substrate.

[0021] According to another aspect of the embodiments of the present invention, a quantum device is provided, comprising the above-mentioned superconducting film.

[0022] Optionally, the quantum device includes: a Fluxonium quantum bit, wherein the Fluxonium quantum bit is prepared using the superconducting film.

[0023] Optionally, the quantum device includes: a Transmon quantum bit, wherein the Transmon quantum bit is prepared using the superconducting film.

[0024] According to yet another aspect of the embodiments of the present invention, a quantum circuit is provided, comprising the above-mentioned quantum device.

[0025] According to yet another aspect of the embodiments of the present invention, a quantum chip is provided, comprising the above-mentioned quantum device.

[0026] According to yet another aspect of the embodiments of the present invention, there is provided a quantum computer, comprising a quantum memory and the above-mentioned quantum chip.

[0027] In the embodiment of the present invention, the first superconducting film is placed in an atmosphere filled with free hydrogen atoms at a second temperature, and hydrogen atoms are filled into the crystal structure defects on a microscopic scale of the first superconducting film, so as to achieve the purpose of preparing a second superconducting film with significantly improved dynamic inductance without introducing other chemical components, thereby achieving the technical effect of increasing the dynamic inductance of the superconducting film used in the quantum circuit, and further solving the technical problem that the dynamic inductance of the superconducting film used in the quantum circuit is not high enough. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of this application. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0029] Figure 1 is a flow chart of a method for preparing a superconducting thin film according to an embodiment of the present invention;

[0030] Figure 2 is a schematic diagram of a method for preparing a superconducting thin film by introducing ammonia gas according to an optional embodiment of the present invention;

[0031] Figure 3 is a schematic diagram of low-temperature measurement results of photoelectron spectroscopy provided according to an optional embodiment of the present invention. DETAILED DESCRIPTION

[0032] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0033] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0034] First, some nouns or terms that appear in the description of the embodiments of the present application are subject to the following explanations:

[0035] Kinetic Inductance is the inertial mass of mobile charge carriers in an AC electric field as a representation of the equivalent series inductance.

[0036] Geometric Inductance is the inductance caused by the geometric shape and size of the quantum device.

[0037] According to an embodiment of the present invention, a method embodiment for preparing a superconducting thin film is provided. It should be noted that the steps shown in the flowchart of the accompanying drawings can be executed in a computer system such as a set of computer executable instructions, and although a logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0038] In order to significantly increase the circuit density under the same circuit size and improve the integration of superconducting quantum devices (such as microwave waveguides, superconducting quantum chips, and superconducting parametric amplifiers), the dynamic inductance of the superconducting film can be adjusted. From formula 1: It can be seen that the frequency ω0 of the superconducting quantum device is determined by the inductance L and capacitance C of the superconducting film. According to formula 2: L = L k +L g It can be seen that the inductance L of the superconducting film is composed of the dynamic inductance Lk and geometric inductance L g At the same time, as the integration of superconducting quantum circuits increases and the size of quantum devices decreases, the geometric inductance L g Therefore, under the premise of maintaining the frequency ω0 of the superconducting quantum device, in order to improve the integration of quantum circuits and increase the density of quantum devices per unit circuit area, the dynamic inductance of the superconducting thin film material can be increased.

[0039] However, the methods proposed in the related art to adjust the dynamic inductance of superconducting thin film materials will have negative effects, for example, it is impossible to guarantee that the quality factor Q of the microwave waveguide will not decrease. The quality factor Q is a dimensionless parameter that represents the damping properties of the oscillator and will directly affect the performance of the microwave waveguide. In addition, according to Formula 3: T = Q / ω q It can be seen that the lifetime T of a superconducting quantum bit is directly affected by the quality factor Q of the quantum circuit. Therefore, how to improve the dynamic inductance of superconducting thin film materials without affecting the quality factor Q of the quantum circuit has become an urgent problem to be solved.

[0040] In the current quantum competition, it is crucial to integrate more quantum bits on a chip of the same size and reduce the area of ​​microwave waveguide circuits. This application proposes a post-processing method for adjusting the dynamic inductance of nitrogen-based superconducting materials, which improves the dynamic inductance of the material without affecting the quality factor of the superconductor, thereby effectively increasing the circuit density and providing a feasible solution for large-scale integrated quantum devices.

[0041] This application provides Figure 1 The method for preparing superconducting thin films is shown. Figure 1 is a flow chart of a method for preparing a superconducting thin film according to an embodiment of the present invention. Figure 1 As shown, the method comprises the following steps:

[0042] Step S102, raising the first atmosphere environment where the first superconducting film is located from the first temperature to the second temperature, so that the first superconducting film is in the second atmosphere environment, wherein the first superconducting film is a superconducting material deposited on a substrate.

[0043] In this step, the first superconducting film is a superconducting material with epitaxial quality deposited on a substrate at a first temperature, and optionally, the substrate can be a sapphire wafer. The superconducting film preparation method provided in this embodiment can be implemented in a low-pressure chemical vapor deposition furnace (LPCVD for short), and the atmosphere provided by the low-pressure chemical vapor deposition furnace for the superconducting film at different times and under different conditions is the first atmosphere environment or the second atmosphere environment in which the first superconducting film in step S102 is located, and the third atmosphere environment involved in subsequent steps.

[0044] Optionally, in the process of raising the first atmosphere in which the first superconducting film is located from the first temperature to the second temperature, the first inert gas can be continuously introduced into the first atmosphere, and the first atmosphere is raised from the first temperature to the second temperature while the first inert gas is continuously introduced, so as to obtain a second atmosphere having a temperature of the second temperature and filled with inert gas. The first inert gas can be any one of high-purity nitrogen, helium, argon, or a similar gas that does not interact with the superconducting film. After the atmosphere in the low-pressure vapor deposition furnace is filled with the high-purity first inert gas, the first inert gas is continuously introduced into the low-pressure vapor deposition furnace and the furnace is heated at the same time, and the temperature in the furnace is raised from the first temperature to the second temperature. It should be noted that the flow rate of the first inert gas introduced into the furnace can be maintained at not less than 3000sccm to ensure that the atmosphere is always filled with inert gas, keep the overall chemical properties of the atmosphere inactive, and avoid introducing impurities into the superconducting film.

[0045] Step S104, after the second atmosphere reaches the second temperature, hydrogen atoms are continuously introduced into the second atmosphere for a predetermined period of time, so that the first superconducting film is placed in a third atmosphere, so that the hydrogen atoms fill the crystal structure defects on a microscopic scale of the first superconducting film, wherein the second temperature is used to maintain the free state of the hydrogen atoms.

[0046] Step S104 is a key step in the method for preparing a superconducting film provided in this embodiment. By maintaining the atmosphere of free hydrogen atoms in the third atmosphere environment for a predetermined period of time, hydrogen atoms and nitrogen atoms can be diffused into the microscopic crystal structure defects in the superconducting film, and the microscopic crystal structure defects of the superconducting film can be uniformly filled, so that the dynamic inductance of the superconducting film is significantly improved. Therefore, the quantum circuit or quantum chip made of the superconducting film treated by this method can significantly reduce the device size, so that the circuit integration can be significantly improved.

[0047] It should be noted that in the process adopted by the embodiments and optional embodiments of the present application, the key step is to control hydrogen atoms to participate in filling the microscopic crystal structure defects in the first superconducting film, wherein the microscopic crystal structure defects in the superconducting material are defects on the atomic or chemical bond scale in the material, and specific structural defect types may include, for example, lattice vacancies, hole defects or isolated bond defects. In this step, by controlling the intrinsic elements in the film to fill such defects, the film density per unit volume can be increased, and the internal gap of the superconducting metal film can be reduced. Since the scattering of Cooper pairs is prohibited when the energy is lower than the gap energy of the superconducting metal, and Cooper pairs are bosons, the dynamic inductance of the superconducting film can be effectively increased.

[0048] At the same time, the first superconducting film is a superconducting material, and the introduction of hydrogen atoms into the film does not change the chemical composition of the superconducting film. Therefore, it can avoid affecting other basic physical parameters of the superconducting film, and can also avoid the decrease of the quality factor Q of the superconducting film. Even due to the processing of step S104, the quality factor Q of the superconducting film using superconducting materials will increase to a certain extent, making the present superconducting film preparation method more valuable in application.

[0049] In addition, in order to maintain the free state of hydrogen atoms in the atmosphere and ensure that hydrogen atoms do not combine with other atoms in the atmosphere in large quantities, the second temperature should be set to a temperature at which hydrogen atoms will not react in the direction of forming chemical bonds, that is, hydrogen atoms can diffuse freely at the second temperature without being bound.

[0050] It should be noted that the above process can be described as the "passivation" of the superconducting film. However, those skilled in the art can understand that calling the phenomenon of using hydrogen atoms to fill the crystal structure defects on the microscopic scale of the nitrogen-based superconducting material "passivation" is a way of expression that is easy to understand and spread, and does not mean that the surface of the superconducting film prepared by the present preparation method has undergone a passivation phenomenon in the macroscopic sense, that is, the passivation phenomenon corresponding to the material surface becoming inactive due to oxidation in the conventional sense.

[0051] As an optional embodiment, the following method can be used to continuously introduce hydrogen atoms into the second atmosphere: continuously introduce hydrogen-containing gas into the second atmosphere, so that the hydrogen-containing gas decomposes at the second temperature to produce free hydrogen atoms, so that the hydrogen atoms fill the microscopic crystal structure defects of the first superconducting film, wherein the second temperature is not lower than the decomposition temperature of the hydrogen-containing gas. Optionally, the chemical element types of the first superconducting film include the chemical element types of the hydrogen-containing gas.

[0052] In the above optional embodiment, the hydrogen-containing gas introduced into the atmosphere preferably has the following properties, that is, all chemical elements included in the hydrogen-containing gas are intrinsic chemical elements of the first superconducting film, that is, one or more free atoms generated after the hydrogen-containing gas is decomposed will not introduce impurity atoms into the first superconducting film during the process of diffusing into the crystal structure defects on the microscopic scale of the first superconducting film, thereby avoiding changes in physical properties of the prepared second superconducting film due to the introduction of impurity atoms.

[0053] Optionally, in order to ensure the stability of the atmosphere and to ensure that the superconducting film is fully, comprehensively and uniformly "passivated", the flow rate of the ammonia hydrogen-containing gas continuously introduced into the atmosphere can be set to no less than 50 sccm, and the predetermined time for treating the first superconducting film can be set to no less than 600 seconds to ensure that the dynamic inductance of the superconducting film can be significantly improved.

[0054] Step S106, after a predetermined period of time, lowering the temperature of the third atmosphere from the second temperature to a third temperature to prepare a second superconducting thin film, wherein the third temperature is lower than the first temperature.

[0055] Among them, the second superconducting film is a product in which the dynamic inductance obtained after preparation is significantly improved compared with the first superconducting film, and the quality factor Q of the second superconducting film is not significantly reduced compared with the first superconducting film. Therefore, the size of the quantum circuit can be reduced without affecting the quality of the quantum circuit, thereby increasing the circuit integration in the quantum chip.

[0056] It should be noted that the third temperature should be ensured to be lower than the first temperature during the cooling process. The purpose of this is to prevent the superconducting film after filling the microscopic crystal structure defects from reacting with the atmosphere gas in the atmosphere at the third temperature, so that the prepared second superconducting film has higher purity and better performance. If the third temperature is not ensured to be lower than the first temperature, additional by-products may be generated in the film during the cooling process, and the physical properties of the film may be changed, and the purpose of preparing a high-purity superconducting film with increased dynamic inductance cannot be achieved.

[0057] As an optional embodiment, in the process of lowering the temperature of the third atmosphere from the second temperature to the third temperature, the second inert gas can be continuously introduced into the third atmosphere in a manner similar to the heating process, and the third atmosphere can be lowered from the second temperature to the third temperature while the second inert gas is continuously introduced. Optionally, the second inert gas can be any one of high-purity nitrogen, helium, argon, or a similar gas that does not interact with the superconducting film. The second inert gas can be the same as the first inert gas or different from the first inert gas. After the atmosphere in the low-pressure vapor deposition furnace is filled with the high-purity second inert gas, the cooling action is started to lower the second temperature to the third temperature, and the second inert gas is continuously introduced into the furnace during the cooling process to keep the overall chemical properties of the environment inactive and avoid introducing impurities into the superconducting film.

[0058] As an optional embodiment, the process of preparing a superconducting film with improved dynamic inductance can occur in a LPCVD reaction tube; the first inert gas and the second inert gas can be pre-stored in a high-purity gas cylinder, and when the first inert gas or the second inert gas is introduced into the atmosphere, the first inert gas and the second inert gas can be introduced into the reaction tube through the gas path provided by LPCVD. Optionally, when the first inert gas and the second inert gas are nitrogen or argon, the purity of the inert gas can be controlled to be above 99.999%. When the hydrogen-containing gas provided to the reaction tube is ammonia, the purity of the ammonia can be controlled to be above 99.9999%, so as to ensure that only hydrogen atoms and nitrogen atoms are introduced into the prepared second superconducting film relative to the first superconducting film, and no other impurities are introduced, so as to ensure that the dynamic inductance of the prepared second superconducting film is significantly improved compared with the first superconducting film and the other physical properties of the film itself are not changed.

[0059] When the temperature of the third atmosphere environment drops to the third temperature, the preparation process is completed, and a second superconducting film with significantly improved dynamic inductance is obtained.

[0060] Through the above steps, the first superconducting film is placed in an atmosphere filled with free hydrogen atoms at a second temperature, and hydrogen atoms are filled into the crystal structure defects on a microscopic scale of the first superconducting film, so as to achieve the purpose of preparing a second superconducting film with significantly improved dynamic inductance without introducing other chemical components, thereby achieving the technical effect of increasing the dynamic inductance of the superconducting film used in the quantum circuit, and further solving the technical problem that the dynamic inductance of the superconducting film used in the quantum circuit is not high enough.

[0061] As an optional embodiment, the superconducting material used in the first superconducting film may be a nitrogen-based superconducting material, a phosphorus-based superconducting material, or a metal-rich carbide superconducting material. In order to ensure that no impurities are introduced into the superconducting material during the process of filling the microscopic crystal structure defects of the first superconducting film, the selection of the hydrogen-containing gas used to split the hydrogen atoms may follow the following principle, that is, the chemical element type of the hydrogen-containing gas does not exceed the chemical element type of the superconducting material of the first superconducting film.

[0062] Optionally, in the case where the superconducting material of the first superconducting film is a nitrogen-based superconducting material, the hydrogen-containing gas can be a nitrogen-hydrogen compound gas containing only two chemical elements, hydrogen and nitrogen, such as ammonia (NH3), and when the hydrogen-containing gas is ammonia, considering that ammonia will decompose into free hydrogen atoms and nitrogen atoms at temperatures of 400 degrees Celsius and above, the second temperature should be set to not less than 400 degrees Celsius.

[0063] Figure 2It is a schematic diagram of a method for preparing a superconducting film by introducing ammonia provided in accordance with an optional embodiment of the present invention. Those skilled in the art will understand that ammonia can be decomposed into hydrogen atoms and nitrogen atoms at an ambient temperature of 400 degrees Celsius. Therefore, when the second temperature is not less than 400 degrees Celsius, the ammonia slowly introduced into the low-pressure vapor deposition furnace can be decomposed into free hydrogen atoms and nitrogen atoms by a higher temperature and filled in the atmosphere, so that the hydrogen atoms and nitrogen atoms gradually diffuse into the crystal structure defects on the microscopic scale of the first superconducting film, so as to achieve the purpose of changing the dynamic inductance of the superconducting film.

[0064] As an optional embodiment, the nitrogen-based superconducting material may include any one of the following: titanium nitride, aluminum nitride, gallium nitride. It should be noted that those skilled in the art can foresee that the superconducting film preparation method provided in the above embodiment is also effective for other nitrides with superconducting properties.

[0065] Optionally, in the case where the superconducting material of the first superconducting film is a phosphorus-based superconducting material, the hydrogen-containing gas may be a phosphine compound gas containing only two chemical elements, hydrogen and phosphorus, such as phosphine (PH3), and when the hydrogen-containing gas is phosphine, the second temperature should be set to a temperature at which phosphine can be decomposed into free hydrogen atoms in consideration of the chemical properties of phosphine. For example, if phosphine can be decomposed into free hydrogen atoms and phosphorus atoms at a temperature of 500 degrees Celsius or above in the physical environment for preparing the second superconducting film, the second temperature may be set to be no less than 500 degrees Celsius.

[0066] Optionally, when the superconducting material of the first superconducting film is a metal-rich carbide superconducting material, the hydrogen-containing gas may be a hydrocarbon gas containing only two chemical elements, hydrogen and carbon, such as methane or acetylene. Optionally, the metal-rich carbide superconducting material may be WRe2C or MoRe2C.

[0067] Table 1 shows the changes in physical parameters of the superconducting film before and after the titanium nitride superconducting film is treated by the superconducting film preparation method provided by an optional embodiment of the present invention. The first superconducting film is a superconducting film before the "passivation" treatment is performed by the above-mentioned superconducting film preparation method, and the second superconducting film is a superconducting film after the "passivation" treatment is performed by the above-mentioned superconducting film preparation method. Rs shown in Table 1 is the surface resistance of the material, and the surface resistance is a physical quantity obtained by dividing the resistivity ρ by the thickness of the material. As shown in Table 1, after the superconducting film is treated by the above-mentioned preparation method, its Rs increases by an average of 37%, and the overall uniformity of the superconducting film also increases. According to the formula: It can be seen that as the R s By increasing the inductance by 37%, the dynamic inductance of the superconducting film can be significantly improved by 17% without affecting the uniformity of the entire film.

[0068] Table 1

[0069] Rs(ohm / ^2) Uniformity Rs(ohm / ^2) The first superconducting film 11.6±0.451 + / -5.9％ About 11.6 The second superconducting film 15.9±0.857 + / -8.4％ About 15.9

[0070] In addition, Table 2 shows the change of the quality factor Q of the resonator prepared by the superconducting film before and after the titanium nitride superconducting film is processed by the superconducting film preparation method provided by the optional embodiment of the present invention. The Q shown in Table 2 i Represents the internal quality factor of the circuit, Q i It is a dimensionless physical quantity, and its reciprocal is 1 / Q i It can be used to directly quantify the loss of the circuit. In Table 2, high energy Q i and low energy Q i They correspond to the power of microwave input, usually the high energy input is greater than 10db, and the low energy is -40db. As shown in Table 2, the quality factor Q of the second superconducting film prepared by the superconducting film preparation method provided by the above embodiment and the optional embodiment does not decrease, and in some cases it is greatly improved, so it has a good market application prospect.

[0071] Table 2

[0072] <![CDATA[Q i (low-power)]]> Qi (high-power) Resonator frequency (MHz) The first superconducting film About 658k About 2873k 5002 The second superconducting film About 759k About 6742k 4888

[0073] Figure 3 include Figure 3 (a) and Figure 3 (b) is a schematic diagram of low temperature measurement results of photoelectron spectroscopy provided according to an optional embodiment of the present invention, such as Figure 3 As shown, the ordinate in the figure is the atomic percentage of the material, and the abscissa is the time for detection using a photoelectron spectrometer. Figure 3 (a) is the detection result of the superconducting film after being processed by the above-mentioned superconducting film preparation method, that is, the depth distribution of the element concentration in the superconducting film sample after the reaction, Figure 3 (b) is the detection result of the superconducting film before being treated by the above superconducting film preparation method, that is, the depth distribution of the element concentration in the superconducting film sample before the reaction. Obviously, before and after the treatment, from the change relationship between the main element concentration of the superconducting film and the depth of the film, the distribution trend of its atomic concentration with the depth is consistent, so the composition ratio of nitrogen, oxygen and titanium in the superconducting film has not changed significantly, so the chemical composition of the superconducting film before and after the treatment is very stable.

[0074] The above-mentioned embodiment and optional embodiment propose an effective post-processing method for superconducting film, which performs "passivation" treatment on the nitrogen-based superconducting film, improves the dynamic inductance of the material without affecting the subsequent process, and no impact on the quality factor Q of the superconducting resonator is found under the test in the microwave frequency domain. Therefore, it provides an effective way to regulate the dynamic inductance of the material, which can be used as an effective solution to increase circuit density.

[0075] It should be noted that, for the above-mentioned method embodiments, for the sake of simplicity, they are all described as a series of action combinations, but those skilled in the art should know that the present invention is not limited by the described action sequence, because according to the present invention, certain steps can be performed in other sequences or simultaneously. Secondly, those skilled in the art should also know that the embodiments described in the specification are all preferred embodiments, and the actions and modules involved are not necessarily required by the present invention.

[0076] The present invention also provides a superconducting film and a microwave component prepared by the above-mentioned superconducting film preparation method, wherein the microwave component can be a microwave waveguide or a microwave resonator, and the microwave component includes a superconducting film grown on a substrate, and the substrate can be a sapphire wafer, and the superconducting film is a superconducting film prepared by any of the above-mentioned embodiments or optional embodiments.

[0077] The present invention also provides a quantum device prepared using the above superconducting film, a quantum circuit and a quantum chip using the quantum device, and a quantum computer including a quantum memory and the above quantum chip. It can be understood by those skilled in the art that the use of the above superconducting film with significantly improved dynamic inductance can reduce the size of the quantum device, thereby improving the integration of quantum circuits and quantum chips, and greatly improving the circuit complexity per unit area.

[0078] Optionally, the quantum device may include a Fluxonium qubit, or the quantum device may also include a Transmon qubit, where the Fluxonium qubit and the Transmon qubit are quantum devices prepared using the superconducting film provided by any of the above embodiments or optional embodiments of the present application.

[0079] The serial numbers of the above embodiments of the present invention are only for description and do not represent the advantages or disadvantages of the embodiments.

[0080] In the above embodiments of the present invention, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0081] In the several embodiments provided in the present application, it should be understood that the disclosed technical content can be implemented in other ways. Among them, the above embodiments can also be implemented in combination with a device for executing program code, wherein the division of the units included in the device is only a logical function division, and there may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of units or modules, which can be electrical or other forms.

[0082] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0083] In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0084] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or all or part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions for a computer device (which can be a personal computer, a server or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), mobile hard disk, magnetic disk or optical disk and other media that can store program codes.

[0085] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for preparing a superconducting thin film, characterized in that: include: Raising a first atmosphere environment where a first superconducting film is located from a first temperature to a second temperature, so that the first superconducting film is in a second atmosphere environment, wherein the first superconducting film is a superconducting material deposited on a substrate; After the second atmosphere reaches the second temperature, hydrogen atoms are continuously introduced into the second atmosphere for a predetermined period of time, so that the first superconducting film is in a third atmosphere, so that the hydrogen atoms fill in the crystal structure defects on a microscopic scale of the first superconducting film, wherein the second temperature is used to maintain the free state of the hydrogen atoms; After the predetermined time, lowering the temperature of the third atmosphere from the second temperature to a third temperature to prepare a second superconducting film, wherein the third temperature is lower than the first temperature; The first atmosphere environment, the second atmosphere environment, and the third atmosphere environment are atmosphere environments provided by the low-pressure vapor deposition furnace for the superconducting film at different times and under different conditions.

2. The method according to claim 1, characterized in that The step of continuously introducing hydrogen atoms into the second atmosphere environment for a predetermined period of time comprises: A hydrogen-containing gas is continuously introduced into the second atmosphere environment so that the hydrogen-containing gas decomposes the hydrogen atoms in a free state at the second temperature, so that the hydrogen atoms fill the crystal structure defects on a microscopic scale of the first superconducting film, wherein the second temperature is not lower than the decomposition temperature of the hydrogen-containing gas.

3. The method according to claim 2, characterized in that The chemical element types of the first superconducting thin film include the chemical element types of the hydrogen-containing gas.

4. The method according to claim 2, characterized in that: The first superconducting film includes: nitrogen-based superconducting material.

5. The method according to claim 4, characterized in that The nitrogen-based superconducting material includes any one of the following: titanium nitride, aluminum nitride, and gallium nitride.

6. The method according to claim 4, characterized in that The hydrogen-containing gas includes nitrogen-hydrogen compounds.

7. The method according to claim 6, characterized in that The nitrogen-hydrogen compound includes ammonia, and the second temperature is not less than 400 degrees Celsius.

8. The method according to claim 2, characterized in that: The first superconducting film includes: phosphorus-based superconducting material.

9. The method according to claim 8, characterized in that The hydrogen-containing gas includes: phosphorus hydrogen compounds.

10. The method according to claim 9, characterized in that The phosphorus hydrogen compound includes PH3, and the second temperature is not less than 500 degrees Celsius.

11. The method according to any one of claims 2 to 10, characterized in that The hydrogen-containing gas is continuously introduced into the second atmosphere at a flow rate of not less than 50 sccm.

12. The method according to claim 11, characterized in that The predetermined duration is not less than 600 seconds.

13. The method according to any one of claims 1 to 10, characterized in that The step of raising the first atmosphere environment where the first superconducting film is located from the first temperature to the second temperature comprises: continuously introducing a first inert gas into the first atmosphere, and raising the first atmosphere from the first temperature to the second temperature while continuously introducing the first inert gas; The step of lowering the temperature of the third atmosphere from the second temperature to a third temperature comprises: The second inert gas is continuously introduced into the third atmosphere, and the third atmosphere is lowered from the second temperature to the third temperature while the second inert gas is continuously introduced.

14. The method according to claim 13, characterized in that The flow rate of the first inert gas introduced into the first atmosphere is not less than 3000 sccm, and the flow rate of the second inert gas introduced into the third atmosphere is not less than 3000 sccm.

15. A superconducting film, characterized in that: The superconducting film is prepared by any one of the methods of claims 1 to 14.

16. A microwave component, characterized in that: include: A substrate and a superconducting thin film as claimed in claim 15, wherein the superconducting thin film is deposited on the substrate.

17. A quantum device, characterized in that: Comprising the superconducting thin film as claimed in claim 15.

18. The quantum device according to claim 17, characterized in that The quantum device includes: a Fluxonium quantum bit, wherein the Fluxonium quantum bit is prepared by using the superconducting film.

19. The quantum device according to claim 17, characterized in that The quantum device includes: a Transmon quantum bit, wherein the Transmon quantum bit is prepared by using the superconducting film.

20. A quantum circuit, characterized in that: A quantum device comprising any one of claims 17 to 19.

21. A quantum chip, characterized in that: A quantum device comprising any one of claims 17 to 19.

22. A quantum computer, characterized in that: include: A quantum memory and a quantum chip as claimed in claim 21.

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