Method for optimizing superconducting transition temperature of NbN thin film on Si substrate at room temperature and application thereof

Abstract

The application discloses a method for optimizing the superconducting transition temperature of a NbN film on a Si substrate at room temperature and application thereof, and comprises the following steps: fixing the Si substrate temperature as room temperature, setting the sputtering power as 100W-300W, setting the deposition gas pressure as 1mTorr-5mTorr, setting the gas mass flow ratio of the reaction gas N2 and the working gas Ar as 15%-35%, setting the sputtering time as 1200s-1500s, and depositing the NbN superconducting film with high superconducting transition temperature on the Si substrate. The superconducting transition temperature of the NbN superconducting film prepared by the method can reach 14.07K, the deposition temperature is room temperature, the preparation method is simple and reliable, has good repeatability, can be produced in industrial batch, and can provide strong material support for the mechanism research of the subsequent NbN superconducting material, the development of a superconducting dynamic inductance detector and engineering application.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of superconducting niobium nitride thin films, and particularly relates to a method for optimizing the superconducting transition temperature of a NbN thin film on a Si substrate at room temperature and application thereof. BACKGROUND

[0002] A superconducting kinetic inductance detector (KID) is one of the most potential ultra-high sensitivity detectors in the next generation. It is a resonant cavity composed of a superconducting thin film planar inductor and a planar capacitor. Incident photons with energy greater than the energy gap of the superconducting material are absorbed by the superconducting thin film, which breaks the Cooper pair and generates quasi-particles. The surface impedance of the superconducting thin film will change, thereby causing changes in the resonant frequency f and the quality factor Q of the resonant cavity. By measuring these weak changes, the information characteristics of the incident photons can be detected. KID adopts a frequency division multiplexing readout method, and usually one feed line can read the signals in hundreds or thousands of KID units. KID has significant advantages in realizing large array integration and improving imaging resolution. KID has great application value in the fields of cosmic astronomical exploration, single photon detection, dark matter detection, security imaging, and biomedical diagnosis.

[0003] Among many low-energy-gap superconducting materials, the superconducting material niobium nitride (NbN) has a relatively high superconducting transition temperature (T c ~ 17K). The superconducting device based on the NbN thin film can work at a temperature of 4.2K liquid helium low-temperature cooler with low cost. In addition, the NbN thin film also has high dynamic inductance, narrow transition width, small superconducting energy gap (Δ(0) ~ 2.5meV), is easy to prepare by using a reaction magnetron sputtering technology, and has good material stability. These characteristics make the NbN thin film widely researched and applied in the fields of superconducting kinetic inductance detector technology, modern single photon detection technology, and terahertz imaging technology.

[0004] NbN film as an important material for preparing high-performance KID, by controlling the preparation conditions and doping concentration of the film, excellent superconducting performance can be obtained, and the performance index of the detector can be improved. At present, most of the researches can greatly improve the superconducting transition temperature of NbN film by using high deposition temperature (> 500 DEG C), inserting buffer layer or selecting MgO single crystal substrate, etc. However, high deposition temperature limits the preparation process of superconducting thin film device, which cannot be compatible with subsequent device such as lift-off process; the method of inserting buffer layer usually involves multiple deposition methods, which cannot guarantee that the whole process of film preparation is carried out in vacuum environment, and the preparation process of buffer layer also needs system optimization, which is complex, and there is also the risk of introducing other impurity ions which is not conducive to the superconducting performance; in addition, MgO single crystal substrate is easy to hydrolyze, and the micro-nano processing technology of subsequent device is not mature, so the NbN film prepared on the substrate and the device based thereon are limited in service life and stability. The NbN film prepared on the high resistance silicon substrate has advantages in subsequent processing (such as further preparing resonant cavity to improve chip performance) and integration with silicon process. Therefore, in order to meet the research and development needs of superconducting dynamic inductance detector, the room temperature deposition of NbN film on Si substrate is carried out, and the regulation and optimization of superconducting transition temperature are realized by improving the growth conditions, which becomes a problem to be solved in the preparation technology of NbN film at present. SUMMARY

[0005] In view of the above, the purpose of the present application is to provide a method for optimizing the superconducting transition temperature of NbN film on Si substrate at room temperature and its application. The method changes the deposition pressure of magnetron sputtering, cooperates with the mass flow ratio of nitrogen and argon, sputtering power and sputtering time, ensures the ionization to form stable glow, and makes the sputtering ions migrate through the appropriate mean free path before reaching the substrate, which is beneficial to obtain nucleation and crystallization when the sputtering atoms reach the substrate surface, reduces the defects in the film, improves the crystalline quality of the film, and thus improves the superconducting transition temperature of the film. The preparation process is simple, suitable for mass production, and can be applied to the research and development of superconducting dynamic inductance detector and other fields.

[0006] In order to achieve the above-mentioned purpose of the application, the technical solutions provided by the present application are as follows:

[0007] The method for optimizing the superconducting transition temperature of NbN film on Si substrate at room temperature provided by the embodiment of the present application comprises the following steps:

[0008] The Si substrate temperature is fixed at room temperature, the sputtering power is 100W-300W, the deposition pressure is 1mTorr-5mTorr, the gas mass flow ratio of reaction gas N2 and working gas Ar is 15%-35%, and the sputtering time is 1200s-1500s. The NbN superconducting film with a superconducting transition temperature of 6-14K is deposited on the Si substrate.

[0009] Preferably, the Si substrate temperature is fixed at room temperature, the sputtering power is 300 W, the deposition pressure is 1 mTorr-5 mTorr, the gas mass flow ratio of the reaction gas N2 and the working gas Ar is 30%, and the sputtering time is 1200 s-1500 s, so that the NbN superconducting thin film with a superconducting transition temperature of 6-14 K is deposited on the Si substrate.

[0010] Another embodiment of the present application provides a method for optimizing the superconducting transition temperature of a NbN thin film on a Si substrate at room temperature, comprising the following steps:

[0011] The Si substrate temperature is fixed at room temperature, the sputtering power is 100 W-300 W, the deposition pressure is 1 mTorr-4 mTorr, the gas mass flow ratio of the reaction gas N2 and the working gas Ar is 15%-35%, and the sputtering time is 1300 s-1500 s, so that the NbN superconducting thin film with a superconducting transition temperature of 9-14 K is deposited on the Si substrate.

[0012] Preferably, the Si substrate temperature is fixed at room temperature, the sputtering power is 300 W, the deposition pressure is 1 mTorr-4 mTorr, the gas mass flow ratio of the reaction gas N2 and the working gas Ar is 30%, and the sputtering time is 1300 s-1500 s, so that the NbN superconducting thin film with a superconducting transition temperature of 9-14 K is deposited on the Si substrate.

[0013] Another embodiment of the present application provides a method for optimizing the superconducting transition temperature of a NbN thin film on a Si substrate at room temperature, comprising the following steps:

[0014] The Si substrate temperature is fixed at room temperature, the sputtering power is 100 W-300 W, the deposition pressure is 2 mTorr-3 mTorr, the gas mass flow ratio of the reaction gas N2 and the working gas Ar is 15%-35%, and the sputtering time is 1400 s-1500 s, so that the NbN superconducting thin film with a superconducting transition temperature of 11-14 K is deposited on the Si substrate.

[0015] Preferably, the Si substrate temperature is fixed at room temperature, the sputtering power is 300 W, the deposition pressure is 2 mTorr-3 mTorr, the gas mass flow ratio of the reaction gas N2 and the working gas Ar is 30%, and the sputtering time is 1400 s-1500 s, so that the NbN superconducting thin film with a superconducting transition temperature of 11-14 K is deposited on the Si substrate.

[0016] Another embodiment of the present application provides a method for optimizing the superconducting transition temperature of a NbN thin film on a Si substrate at room temperature, comprising the following steps:

[0017] The Si substrate is fixed at room temperature, the sputtering power is 100-300W, the deposition pressure is 3-4mTorr, the mass flow ratio of the reaction gas N2 and the working gas Ar is 15-35%, and the sputtering time is 1400-1500s, so that the NbN superconducting thin film with a superconducting transition temperature of 9-11K is deposited on the Si substrate.

[0018] Preferably, the Si substrate is fixed at room temperature, the sputtering power is 300W, the deposition pressure is 3-4mTorr, the mass flow ratio of the reaction gas N2 and the working gas Ar is 30%, and the sputtering time is 1400-1500s, so that the NbN superconducting thin film with a superconducting transition temperature of 9-11K is deposited on the Si substrate.

[0019] Preferably, the metal Nb target is selected when depositing the NbN superconducting thin film, the metal Nb target is loaded into the plating cavity of the magnetron sputtering equipment before deposition, and the vacuum is extracted to ultrahigh vacuum, the base vacuum degree of the ultrahigh vacuum is less than 5.0*10 -8 Torr.

[0020] Preferably, the high-resistance Si substrate is selected when depositing the NbN superconducting thin film, and the high-resistance Si substrate is subjected to ion cleaning before use to remove impurity ions on the substrate surface, wherein the ion beam of the ion cleaning is an argon ion beam, the ion cleaning vacuum environment is less than 5.0*10 -8 Torr, the argon flow is 20-100sccm, the ion source power is 30-100W, the working pressure is 1.0-10.0mTorr, and the ion cleaning time is 60-300s.

[0021] Preferably, the NbN thin film is pre-sputtered before depositing the NbN superconducting thin film, and the mass flow ratio of the reaction gas N2 and the working gas Ar is set to 5-50% during pre-sputtering, the sputtering power is 50-800W, the deposition pressure is 1.0-10.0mTorr, and the sputtering time is 60-300s.

[0022] The embodiment of the present application also provides a NbN superconducting thin film with a high superconducting transition temperature, which is prepared by the above method, and the thickness of the NbN superconducting thin film is 140-160nm.

[0023] The embodiment of the present application also provides an application of the method for optimizing the superconducting transition temperature of the NbN thin film on a room-temperature Si substrate in a superconducting dynamic inductance detector, and the NbN superconducting thin film with a high superconducting transition temperature prepared by the method is used as a superconducting thin film planar inductor in the superconducting dynamic inductance detector.

[0024] Compared with the prior art, the present application has the beneficial effects at least including:

[0025] The present application provides a method for optimizing the superconducting transition temperature of NbN thin film on Si substrate at room temperature and its application. In the embodiment, the superconducting transition temperature of the prepared NbN superconducting thin film can reach 14.07 K, which is significantly higher than the level reported in the literature under the same conditions. The deposition temperature is room temperature, the preparation method is simple and reliable, has good repeatability, can be mass-produced, and at the same time provides strong material support for the subsequent mechanism research of NbN superconducting material, the development of superconducting dynamic inductance detector and its engineering application. BRIEF DESCRIPTION OF DRAWINGS

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or prior art description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0027] Figure 1 is the XRD diffraction pattern of the NbN thin film deposited under the condition of nitrogen argon flow ratio 30%, sputtering power 300 W and deposition pressure 1.0 mTorr-8.0 mTorr provided by the embodiment of the present application;

[0028] Figure 2 is the SEM photo of the NbN superconducting thin film deposited under the condition of nitrogen argon flow ratio 30%, sputtering power 300 W and deposition pressure 1.0 mTorr provided by the embodiment of the present application;

[0029] Figure 3 is the SEM photo of the NbN superconducting thin film deposited under the condition of nitrogen argon flow ratio 30%, sputtering power 300 W and deposition pressure 2.0 mTorr provided by the embodiment of the present application;

[0030] Figure 4 is the curve of the normalized resistance of the NbN superconducting thin film changing with temperature under the condition of nitrogen argon flow ratio 30%, sputtering power 300 W and deposition pressure 1 mTorr, 2 mTorr, 3 mTorr, 4 mTorr and 5 mTorr provided by the embodiment of the present application;

[0031] Figure 5 is the curve of the superconducting transition temperature of the NbN superconducting thin film changing with deposition pressure under the condition of nitrogen argon flow ratio 30%, sputtering power 300 W and deposition pressure 1 mTorr, 2 mTorr, 3 mTorr, 4 mTorr and 5 mTorr provided by the embodiment of the present application. DETAILED DESCRIPTION

[0032] In order to make the objects, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and do not limit the protection scope of the present application.

[0033] The inventive concept of the present application is that, in order to solve the problem that the superconducting transition temperature is reduced due to a large lattice mismatch in the prior art of depositing a NbN thin film directly on a Si substrate, the embodiments of the present application provide a method for optimizing the superconducting transition temperature of a NbN thin film on a Si substrate at room temperature and an application thereof. The method comprises the following steps: preparing a NbN thin film on a high-resistance Si substrate by a reactive magnetron sputtering method, fixing the temperature of the Si substrate at room temperature, and adopting a proper mass flow ratio of nitrogen gas to argon gas, a sputtering power and a sputtering time, and intentionally adjusting a deposition pressure to control the speed and energy of sputtering particles when reaching the Si substrate, so as to change the phase formation mode and crystal nucleation mode in the growth process of the NbN superconducting thin film, effectively change the defect area, interface area and kinetic process state generated in the crystal growth process, and finally realize the control of the superconducting transition temperature of the NbN thin film.

[0034] The embodiments provide a method for optimizing the superconducting transition temperature of a NbN thin film on a Si substrate at room temperature, which comprises the following steps:

[0035] Step 1: target material preparation and processing

[0036] A metal Nb target material with a purity of 99.99% is prepared, and the metal Nb target material is loaded into a film plating cavity of a high-vacuum magnetron sputtering system and is pumped to ultra-high vacuum. When the vacuum degree is insufficient, the motion of the plasma may be affected, the controllability and repeatability of the thin film deposition process may be reduced, therefore, the base vacuum degree of the film plating cavity is less than 5.0*10 -8 Torr.

[0037] Step 2: selection and processing of the substrate

[0038] The substrate is a high-resistance Si substrate. The Si substrate is compatible with a mature semiconductor process, and the growth of a high superconducting transition temperature thin film on the Si substrate at room temperature is helpful to promote the preparation and application of the material in a superconducting detector.

[0039] As for the processing of the Si substrate, the Si substrate is placed into a sample transfer cavity of a magnetron sputtering device and is pumped to vacuum. When the vacuum degree is less than 5.0*10 -6 Torr, the substrate is placed into a film plating cavity of the magnetron sputtering device. Before pre-sputtering, the substrate needs to be ion cleaned for 1-3 minutes to remove impurity ions on the surface of the substrate. The ion beam of the ion cleaning can be an argon ion beam, and the vacuum environment of the ion cleaning is less than 5.0*10 -8Torr, argon flow rate of 20sccm ~ 100sccm, ion source power of 30W ~ 100W, working pressure of 1.0mTorr ~ 10.0mTorr, ion cleaning time control in 60s ~ 300s.

[0040] Step 3, NbN film pre-sputtering:

[0041] The main reason for pre-sputtering is that the target material is easy to attach impurities when not used for a long time, and many target materials are easy to oxidize after the surface is exposed to air. If direct sputtering is performed, it is easy to cause the composition of the thin film to be impure and the quality to be poor. A certain pre-sputtering time can ensure the purity of the target sputtering.

[0042] When pre-sputtering, first set the mass flow ratio of the reaction gas N2 and the working gas Ar to 5% ~ 50%, then open the power source to set the sputtering power to 50W ~ 800W, adjust the working pressure of the chamber to 1.0mTorr ~ 10.0mTorr, turn on the power source to start the glow, and after the glow is successfully started, a layer of glow can be seen on the surface of the target from the observation window. At this time, the working pressure can be reduced for pre-sputtering, and the sputtering time is 60s ~ 300s.

[0043] Step 4, NbN film deposition:

[0044] After pre-sputtering is completed, open the baffle plate above the target, fix the Si substrate temperature at room temperature, the sputtering power is 100W ~ 300W and the deposition pressure is 1mTorr-8mTorr, at this time, check and adjust the gas mass flow ratio of the reaction gas N2 and the working gas Ar to 15% ~ 35%, set the sputtering time according to the expected sputtering rate 1200 ~ 1500s, open the baffle plate above the target, and sputter the main NbN film layer. The thickness of the obtained NbN main film layer is 150 ± 10 nm.

[0045] Step 5, sampling:

[0046] After the set sputtering time is reached, the sputtering is completed. The instrument timer is 0, which automatically turns off the power source, then closes the baffle plate, closes the plug valve, and transfers the substrate to the sample transfer chamber. Open the air inlet valve of the sample transfer chamber to ventilate until the air pressure in the sample transfer chamber returns to atmospheric pressure, then open the chamber door and take out the sample.

[0047] The NbN thin films of the following specific examples and comparative examples are prepared based on the above steps 1 ~ 5 as shown in Table 1:

[0048] Table 1

[0049]

[0050]

[0051] Figure 1 XRD diffraction patterns of the NbN thin film deposited under the conditions of a nitrogen argon flow ratio of 30%, a sputtering power of 300 W and a deposition pressure of 1.0 mTorr to 8.0 mTorr. By analyzing the XRD diffraction patterns, it can be obtained that the NbN thin film is a face-centered cubic δ-NbN phase and a polycrystalline thin film, when the deposition pressure is 1 mTorr, the diffraction peaks of the NbN thin film are very weak; with the increase of the deposition pressure, the diffraction peaks of NbN(111) and NbN(200) first increase and then weaken, when the pressure is greater than 3.0 mTorr, the diffraction peak of (200) diffraction peak weakens. This is mainly because when the deposition pressure is low, the ionization of the gas is relatively difficult, the concentration of the sputtering particles reaching the substrate is limited, and the crystallization ability decreases; when the overall pressure is large (>3 mTorr), the concentration of N2 molecules in the preparation environment increases, and the probability of collision between Nb ions and N ions increases during the process of reaching the substrate surface, resulting in a large kinetic energy loss, thereby causing the crystallinity of the thin film to be poor. When the deposition pressure is appropriate, under the premise of ensuring that a stable glow can be formed, the sputtering particles can obtain a more suitable kinetic energy under the action of the voltage, find a suitable lattice position for film formation, thereby facilitating the nucleation and crystallization of the sputtering atoms when they reach the substrate surface, thereby reducing the defects in the thin film and improving the crystalline quality of the thin film, thereby improving the superconducting transition temperature of the thin film.

[0052] Figure 2 is an SEM photo of the NbN superconducting thin film provided by the embodiment of the present application under the conditions of a nitrogen argon flow ratio of 30%, a sputtering power of 300 W and a deposition pressure of 1.0 mTorr, Figure 3 is an SEM photo of the NbN superconducting thin film provided by the embodiment of the present application under the conditions of a nitrogen argon flow ratio of 30%, a sputtering power of 300 W and a deposition pressure of 2.0 mTorr. By analyzing the SEM photo, it can be obtained that for example 1, when the deposition pressure is 1 mTorr, the surface of the NbN thin film is very smooth, and under the condition of a magnification of 100,000, there is no clear crystal grain, which indicates that the crystalline quality of the thin film at this time is poor, which is also consistent with the fact that Figure 1 the diffraction peaks of the NbN thin film in the XRD are weak; for example 2, when the deposition pressure is 2 mTorr, under the same magnification condition, the surface crystal grains of the NbN thin film are clearly visible and uniform in size, which indicates that the thin film at this time has high crystalline quality.

[0053] Figure 4 is a curve of the normalized resistance of the NbN superconducting thin film provided by the embodiment of the present application changing with temperature under the conditions of a nitrogen argon flow ratio of 30%, a sputtering power of 300 W and a deposition pressure of 1 mTorr, 2 mTorr, 3 mTorr, 4 mTorr and 5 mTorr, Figure 5 is a curve of the normalized resistance of the NbN superconducting thin film provided by the embodiment of the present application changing with temperature under the conditions of a nitrogen argon flow ratio of 30%, a sputtering power of 300 W and a deposition pressure of 1 mTorr, 2 mTorr, 3 mTorr, 4 mTorr and 5 mTorr, Figure 4The superconducting transition temperature of the corresponding NbN superconducting thin film under the same conditions changes with the deposition pressure. Analysis shows that the superconducting transition temperature of the NbN thin film prepared by examples 1-5 increases first and then decreases with the increase of the deposition pressure. The superconducting transition temperature of the NbN thin film is 8.8K, 14.07K, 11.3K, 9.07K and 6.69K. When the deposition pressure is 2mTorr, the superconducting transition temperature of the NbN thin film is the highest, which is 14.07K. This is mainly because when the deposition pressure is low, the ionization of the gas is relatively difficult, the concentration of the sputtering particles reaching the substrate is limited, and the crystalline quality of the thin film is poor. When the overall deposition pressure is large (5mTorr), the concentration of N2 molecules in the preparation environment increases, and the probability of collision between Nb ions and N ions increases during the process of reaching the substrate surface, which leads to a large loss of kinetic energy, and also leads to poor crystallinity of the thin film. When the deposition pressure is appropriate, under the premise of ensuring that a stable glow discharge can be formed, the sputtering particles can obtain a more suitable kinetic energy under the action of voltage, find a suitable lattice position for film formation, thereby facilitating the nucleation and crystallization of the sputtering atoms reaching the substrate surface, thereby reducing the defects in the thin film and improving the crystalline quality of the thin film. The crystalline quality of the thin film directly determines the superconducting transition temperature of the thin film.

[0054] In summary, the present application provides a method for optimizing the superconducting transition temperature of NbN thin film on Si substrate at room temperature. The NbN thin film is prepared on high resistance Si substrate by reactive magnetron sputtering method. The Si substrate temperature is fixed at room temperature. The mass flow ratio of nitrogen and argon, the sputtering power and the sputtering time are appropriately adjusted. The deposition pressure is intentionally adjusted to control the speed and energy of the sputtering particles reaching the Si substrate, thereby changing the phase formation mode and crystal nucleation mode during the growth of the NbN thin film, effectively changing the defect zone, interface zone and kinetic process state generated during the crystal growth process, and finally realizing the regulation and optimization of the superconducting transition temperature of the NbN thin film. The NbN thin film with high superconducting transition temperature is prepared. The preparation method is simple and reliable, has good repeatability, can be produced in industrial batch, and can be applied to the superconducting thin film planar inductance in the superconducting dynamic inductance detector and other applications.

[0055] The above specific embodiments have described the technical solutions and advantages of the present application in detail. It should be understood that the above description is only the most preferred embodiment of the present application and is not intended to limit the present application. Any modification, supplement and equivalent replacement made within the principle range of the present application should be included in the protection scope of the present application.

Claims

1. A method for optimizing the superconducting transition temperature of NbN thin films on Si substrates at room temperature, characterized in that, Includes the following steps: With the Si substrate temperature fixed at room temperature, sputtering power at 300 W, deposition gas pressure at 2 mTorr, gas mass flow rate ratio of reactive gas N2 to working gas Ar at 30%, and sputtering time at 1500 s, an NbN superconducting thin film with a superconducting transition temperature of 14.07 K was deposited on the Si substrate.

2. The method for optimizing the superconducting transition temperature of NbN thin films on Si substrates at room temperature according to claim 1, characterized in that, When depositing NbN superconducting thin films, a metallic Nb target is selected. Before deposition, the metallic Nb target is loaded into the deposition chamber of the magnetron sputtering equipment, and the vacuum is evacuated to an ultra-high vacuum level, with a base vacuum degree of <5.0×10⁻⁶. -8 Torr.

3. The method for optimizing the superconducting transition temperature of NbN thin films on Si substrates at room temperature according to claim 1, characterized in that, High-resistivity Si substrates were selected for depositing NbN superconducting thin films. Before use, the high-resistivity Si substrates underwent ion cleaning to remove impurity ions from their surface. The ion beam used for ion cleaning was an argon ion beam, and the ion cleaning vacuum environment was <5.0 × 10⁻⁶. -8 Torr, argon flow rate of 20 sccm~100 sccm, ion source power of 30W~100W, working pressure of 1.0 mTorr~10.0 mTorr, ion cleaning time of 60s~300s.

4. The method for optimizing the superconducting transition temperature of NbN thin films on Si substrates at room temperature according to claim 1, characterized in that, Before depositing NbN superconducting thin films, NbN thin film pre-sputtering is performed. During pre-sputtering, the mass flow rate ratio of reactive gas N2 to working gas Ar is set to 5%~50%, the sputtering power is 50W~800W, the deposition gas pressure is 1.0mTorr~10.0mTorr, and the sputtering time is 60s~300s.

5. A NbN superconducting thin film with a high superconducting transition temperature, characterized in that, The NbN superconducting thin film with a high superconducting transition temperature is prepared by the method described in any one of claims 1-4, and the thickness of the NbN superconducting thin film is 160 nm.

6. The application of a method for optimizing the superconducting transition temperature of NbN thin films on Si substrates at room temperature as described in any one of claims 1-4 in a superconducting dynamic inductive detector, characterized in that, The method described above is used to prepare NbN superconducting thin films with high superconducting transition temperatures, which are then used as superconducting thin-film planar inductors in superconducting dynamic inductance detectors.

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