CN111953308B - A kind of magnetic flux-driven Josephson parametric amplifier and preparation method thereof - Google Patents

Abstract

The invention provides a magnetic flux-driven Josephson parametric amplifier and a preparation method thereof. The preparation method includes: forming a Nb/Al-AlOx/Nb laminated structure on the surface of a substrate; etching the Nb/Al-AlOx/Nb laminated layer structure to form a coplanar waveguide resonator structure, a pump line structure, a ground line structure, a signal input wiring structure and a pump input wiring structure, and Nb/Al‑AlOx/Nb Josephson is formed in the coplanar waveguide resonator structure. junction; an insulating layer is formed on the surface of the above-mentioned structure, and the insulating layer is etched to form a Josephson junction via hole, a ground via hole, an input signal pin via hole and a pump input pin via hole; a superconducting thin film layer is formed on the surface of the above structure , etch the superconducting thin film layer to electrically connect the Josephson junction via and the ground via, and at the same time form the ground pin in the ground via, the input signal pin in the input signal pin via, and the pump input The pump input pins are formed in the pin vias.

Description

Magnetic flux-driven Josephson parametric amplifier and preparation method thereof

technical field

The invention belongs to superconducting electronics, in particular to a magnetic flux-driven Josephson parametric amplifier and a preparation method thereof.

Background technique

As a new type of computing tool, quantum computer uses the superposition principle of quantum mechanics and the characteristics of quantum entanglement, and has powerful parallel computing capabilities. Superconducting qubits have become one of the most likely solutions to realize quantum computers due to their low loss, good scalability, and compatibility with traditional micro-nano processing technologies. In the qubit measurement experiment, in order to protect the state of the qubit, the measurement signal power is very small, and an external amplifier is required at the output end of the circuit to amplify the output signal. Commercial HEMTs (High Electron Mobility Transistors) have noise temperatures around 4K and are difficult to use for single shot read out non-destructive readout of qubits.

Josephson Parametric Amplifier (JPA) is based on the nonlinear inductance characteristics of the Josephson junction. Under the action of an appropriate pump frequency, the energy of the pump signal is converted into the energy of the frequency of the amplified signal, so as to realize the amplification of the input signal. enlarge. The noise level of JPA is close to the quantum limit noise, and it can be used as the first-stage amplifier of the superconducting qubit circuit, which greatly improves the signal-to-noise ratio of the readout signal and realizes the single-shot non-destructive readout of the qubit.

In the prior art, the Josephson junction, a key circuit element of JPA, adopts an Al/AlOx/Al three-layer film structure. The preparation method of the structure is as follows: first, the double-layer photoresists 102 and 103 on the substrate 101 are exposed and developed to form Suspended bridge 104 or asymmetric undercut structure (as shown in Fig. 1-2), and then Al/AlOx/Al tunnel junction 108 (as shown in Fig. 3-5) is prepared by electron beam double-angle oblique evaporation and in-situ oxidation process shown), and finally strip the double-layer photoresist (as shown in Figure 6). The existing preparation method has the following shortcomings: 1) Al Josephson junction prepared by double-angle evaporation, although the process steps are few, but because the suspension bridge itself is relatively fragile, it is difficult to use plasma on the surface of the substrate or the Josephson junction before evaporating the film. Etching and cleaning; 2) Using double-layer photoresist to prepare Al Josephson junction, there will be redundant patterns (shown in the dotted box in Figure 6), which is not conducive to the realization of the scale of integrated circuits; 3) Superconductivity of Al thin films The transition temperature is lower (about 1K or so), and it needs to work at a lower temperature.

SUMMARY OF THE INVENTION

In view of the above shortcomings of the prior art, the purpose of the present invention is to provide a magnetic flux-driven Josephson parametric amplifier and a preparation method thereof, which are used to solve many problems existing in the preparation process of the existing Al/AlOx/Al tunnel junction.

In order to achieve the above purpose and other related purposes, the present invention provides a preparation method of a magnetic flux-driven Josephson parametric amplifier, the preparation method comprising:

1) provide a substrate;

2) forming a Nb/Al-AlOx/Nb laminated structure on the upper surface of the substrate;

3) The upper Nb layer, the Al-AlOx layer and the lower Nb layer in the Nb/Al-AlOx/Nb laminated structure are sequentially etched to form a coplanar waveguide resonator structure and a pump line structure, and at the same time A ground wire structure is formed between the coplanar waveguide resonator structure and the pump line structure, a signal input wiring structure is formed on the other side of the coplanar waveguide resonator structure, and a signal input wiring structure is formed on the other side of the pump line structure. A pump input wiring structure is formed on one side; wherein, a Nb/Al-AlOx/Nb Josephson junction is formed in the coplanar waveguide resonator structure;

4) An insulating layer is formed on the upper surface of the structure in step 3), and the insulating layer is etched to form a Josephson junction via on the surface of the Nb/Al-AlOx/Nb Josephson junction, and A ground via hole is formed on the surface of the ground wire structure, an input signal pin via hole is formed on the surface of the signal input wiring structure, and a pump input pin via hole is formed on the surface of the pump input wiring structure;

5) A superconducting thin film layer is formed on the upper surface of the structure in step 4), and the superconducting thin film layer is etched to electrically connect the Josephson junction via and the ground via, and at the same time A ground pin is formed in the ground via hole, an input signal pin is formed in the input signal pin via hole, and a pump input pin is formed in the pump input pin via hole.

Optionally, the preparation method further includes: cleaning the substrate in step 1).

Optionally, the method for forming the Nb/Al-AlOx/Nb laminated structure in step 2) includes: firstly using a DC magnetron sputtering in-situ growth method to sequentially form a lower Nb layer and an Al layer on the upper surface of the substrate. Then, an AlOx layer is formed on the surface of the Al layer by a static oxidation method to obtain an Al-AlOx layer, and finally a DC magnetron sputtering in-situ growth method is used to form an upper Nb layer on the upper surface of the Al-AlOx layer.

Optionally, the thickness of the lower Nb layer is greater than its magnetic field penetration depth, the thickness of the Al layer is less than the coherence length of the lower Nb layer, and the thickness of the AlOx layer is related to the critical current density of the Josephson junction. Inversely proportional, the thickness of the upper Nb layer is greater than its magnetic field penetration depth.

Optionally, the method for forming the coplanar waveguide resonant cavity structure, the pump line structure, the ground line structure, the signal input wiring structure, and the pump input wiring structure in step 3) includes: :

3-1) etching the upper Nb layer until the Al-AlOx layer is exposed, to define a Josephson junction region based on the upper Nb layer remaining after etching;

3-2) etching the Al-AlOx layer until the lower Nb layer is exposed, wherein the Al-AlOx layer remaining after etching is located in the Josephson junction region;

3-3) Etching the lower Nb layer until the substrate is exposed to form the coplanar waveguide resonator structure, the pump line structure, the ground line structure, and the signal input wiring The structure and the pump input wiring structure; wherein, the Josephson junction region is formed at the end of the coplanar waveguide resonator structure, and the Nb/Al-AlOx/Nb Josephson junction is formed therein.

Optionally, the area of the Al-AlOx layer remaining after the etching is larger than the area of the upper Nb layer remaining after the etching.

Optionally, the material of the insulating layer includes SiO ₂ , and the material of the superconducting thin film layer includes Nb.

The present invention also provides a magnetic flux-driven Josephson parametric amplifier prepared by the above preparation method, the Josephson parametric amplifier comprising:

substrate;

a coplanar waveguide resonator structure, formed on the upper surface of the substrate, wherein an Nb/Al-AlOx/Nb Josephson junction is formed;

a pump line structure formed on the upper surface of the substrate and located on one side of the coplanar waveguide resonator structure;

a ground wire structure formed on the upper surface of the substrate and located between the coplanar waveguide resonator structure and the pump wire structure;

a signal input wiring structure, formed on the upper surface of the substrate and located on the other side of the coplanar waveguide resonator structure;

a pumping input wiring structure formed on the upper surface of the substrate and located on the other side of the pumping line structure;

an insulating layer formed on the coplanar waveguide resonator structure, the pump line structure, the ground line structure, the signal input wiring structure, the pump input wiring structure and part of the substrate upper surface, and a Josephson junction via hole is formed on the surface of the Nb/Al-AlOx/Nb Josephson junction, a ground via hole is formed on the surface of the ground wire structure, and a surface of the signal input wiring structure is formed with input signal pin via holes, and pump input pin via holes are formed on the surface of the pump input wiring structure;

The superconducting thin film layer is formed on the upper surface of the Josephson junction via hole, the ground via hole, the input signal pin via hole, the pump input pin via hole and part of the insulating layer, so as to The Josephson junction via and the ground via are electrically connected, and a ground pin is formed in the ground via, an input signal pin is formed in the input signal pin via, and an input signal pin is formed in the pump The pump input pin is formed in the pump input pin via.

As described above, a magnetic flux-driven Josephson parametric amplifier and a preparation method thereof of the present invention utilize the existing micro-nano processing technology to etch the Nb/Al-AlOx/Nb laminated structure to form a Nb/Al-AlOx /Nb Josephson junction coplanar waveguide resonant cavity series superconducting quantum interference instrument structure, and a pump line structure is also formed, which solves the problems of difficulty in cleaning the substrate, redundant patterns and low superconducting transition temperature in the prior art. The performance of the Josephson parametric amplifier is greatly improved; the preparation method of the present invention is compatible with the traditional semiconductor process, and the prepared Josephson parametric amplifier can achieve a gain of 20dB, a noise temperature below 400mK, and has good cold-heat cycle. High operating temperature (can work in liquid helium temperature region (4.2K)), good junction uniformity, and easy large-scale expansion of integrated circuits.

Description of drawings

FIG. 1 is a schematic diagram showing the structure of forming a double-layer photoresist on a substrate in the prior art.

FIG. 2 is a schematic diagram showing the structure of forming a suspension bridge by exposing and developing a double-layer photoresist in the prior art.

FIG. 3 shows a schematic structural diagram of an Al layer prepared by an angle oblique evaporation process in the prior art.

FIG. 4 is a schematic diagram showing the structure of an AlOx layer prepared by an in-situ oxidation process in the prior art.

FIG. 5 shows a schematic structural diagram of an Al layer prepared by an angle oblique evaporation process in the prior art, wherein the inclination angles of the angle oblique evaporation process in FIG. 5 and FIG. 3 are different.

FIG. 6 is a schematic diagram showing the structure of stripping a double-layer photoresist in the prior art.

Figure 7 shows a flow chart of the preparation method of the present invention.

FIG. 8 is a schematic diagram showing the structure of the Nb/Al-AlOx/Nb stacked structure formed on the substrate.

FIG. 9 shows a schematic diagram of the structure after etching the upper Nb layer.

FIG. 10 shows a schematic diagram of the structure after etching the Al-AlOx layer.

FIG. 11 shows a schematic diagram of the structure after etching the lower Nb layer.

FIG. 12 is a schematic diagram showing the structure of forming the insulating layer.

FIG. 13 shows a schematic diagram of the structure after etching the insulating layer.

FIG. 14 is a schematic diagram showing the structure of forming a superconducting thin film layer.

FIG. 15 shows a schematic diagram of the structure after the superconducting thin film layer is etched.

Component label description

101 Substrate

102 The first layer of photoresist

103 Second layer photoresist

104 Suspension Bridge

105, 107 Al layer

106 AlOx layer

108 Al/AlOx/Al tunnel junction

201 Substrate

202 Nb/Al-AlOx/Nb stack structure

2021 Lower Nb layer

2022 Al-AlOx layer

2023 Upper Nb layer

203 Coplanar waveguide resonator structure

204 Pump Line Structure

205 Ground wire structure

206 Signal input wiring structure

207 Pump input wiring structure

208 Nb/Al-AlOx/Nb Josephson junction

209 Insulation layer

210 Josephson Junction Via

211 Ground Via

212 Input signal pin via

213 Pump input pin via

214 superconducting thin film layer

215 Ground pin

216 Input signal pin

217 Pump input pin

Detailed ways

The embodiments of the present invention are described below through specific specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

See Figures 7 to 15. It should be noted that the diagrams provided in this embodiment are only to illustrate the basic concept of the present invention in a schematic way, although the diagrams only show the components related to the present invention rather than the number, shape and the number of components in actual implementation. For dimension drawing, the shape, quantity and proportion of each component can be arbitrarily changed during actual implementation, and the component layout shape may also be more complicated.

As shown in FIG. 7 , this embodiment provides a preparation method of a magnetic flux-driven Josephson parametric amplifier, and the preparation method includes:

1) providing a substrate 201;

2) forming a Nb/Al-AlOx/Nb laminated structure 202 on the upper surface of the substrate 201;

3) Etch the upper Nb layer 2023, the Al-AlOx layer 2022 and the lower Nb layer 2021 in the Nb/Al-AlOx/Nb laminated structure 202 in sequence to form the coplanar waveguide resonator structure 203 and the pump line At the same time, a ground wire structure 205 is formed between the coplanar waveguide resonator structure 203 and the pump line structure 204, and a signal input wiring structure is formed on the other side of the coplanar waveguide resonator structure 203. 206. A pump input wiring structure 207 is formed on the other side of the pump line structure 204; wherein, an Nb/Al-AlOx/Nb Josephson junction 208 is formed in the coplanar waveguide resonator structure 203;

4) forming an insulating layer 209 on the upper surface of the structure in step 3), and etching the insulating layer 209 to form Josephson junction vias on the surface of the Nb/Al-AlOx/Nb Josephson junction 208 210. Form a ground via hole 211 on the surface of the ground wire structure 205, form an input signal pin via hole 212 on the surface of the signal input wiring structure 206, and form a pump input on the surface of the pump input wiring structure 207 Pin vias 213;

5) A superconducting thin film layer 214 is formed on the upper surface of the structure in step 4), and the superconducting thin film layer 214 is etched to electrically connect the Josephson junction via 210 and the ground via 211. connection, at the same time, the ground pin 215 is formed in the ground via hole 211, the input signal pin 216 is formed in the input signal pin via hole 212, and the pump is formed in the pump input pin via hole 213. Input pin 217.

In the following, please refer to FIG. 7 and FIGS. 8 to 15 to describe the manufacturing method of the magnetic flux-driven Josephson parametric amplifier in this embodiment in detail.

In step 1), as shown in FIG. 8, a substrate 201 is provided; wherein, the substrate 201 includes silicon wafer or sapphire; of course, other substrate materials for preparing the magnetic flux-driven Josephson parametric amplifier are the same applies to this example.

As an example, the preparation method further includes the step of cleaning the substrate 201 to remove impurities on its surface and improve the quality of subsequent thin film growth, thereby improving the quality factor of the device and improving the quality of the Josephson junction.

Specifically, a buffered hydrofluoric acid (BHF) solution can be used to clean the surface of the substrate 201; of course, other suitable solutions can also be used to clean the surface of the substrate 201, such as using food Mermaid solution (a mixture of concentrated sulfuric acid and hydrogen peroxide), etc.

In step 2), as shown in FIG. 8 , a Nb/Al-AlOx/Nb stacked structure 202 is formed on the upper surface of the substrate 201 .

As an example, the method for forming the Nb/Al-AlOx/Nb layered structure 202 includes: firstly using a DC magnetron sputtering in-situ growth method to sequentially form a lower Nb layer 2021 and an Al layer ( (not shown in the figure), then an AlOx layer (not shown in the figure) is formed on the surface of the Al layer by a static oxidation method to obtain an Al-AlOx layer 2022, and finally a DC magnetron sputtering in-situ growth method is used on the surface of the Al layer. An upper Nb layer 2023 is formed on the upper surface of the Al-AlOx layer 2022.

Specifically, the thickness of the lower Nb layer 2021 is greater than its magnetic field penetration depth, and the thickness of the upper Nb layer 2023 is greater than its magnetic field penetration depth; it should be noted that the magnetic field penetration depth here is mainly determined by the material It is determined by itself, so the corresponding magnetic field penetration depth can be determined when the material is selected. Optionally, the thickness of the lower Nb layer 2021 is equal to the thickness of the upper Nb layer 2023, for example, 150 nm.

Specifically, the thickness of the Al layer is smaller than the coherence length of the lower Nb layer 2021, such as 10 nm; it should be noted that the coherence length here is also determined by the material itself, so when the material is selected, its corresponding coherence length length can be determined.

Specifically, the thickness of the AlOx layer is inversely proportional to the critical current density of the Josephson junction. In specific applications, the thickness of the AlOx layer may be determined according to the critical current density of the Josephson junction actually required.

In step 3), as shown in FIGS. 9-11, the upper Nb layer 2023, the Al-AlOx layer 2022 and the lower Nb layer 2021 in the Nb/Al-AlOx/Nb stacked structure 202 are etched in sequence, A coplanar waveguide resonator structure 203 and a pump line structure 204 are formed, and a ground line structure 205 is formed between the coplanar waveguide resonator structure 203 and the pump line structure 204, and a ground line structure 205 is formed between the coplanar waveguide resonator structure 203 and the pump line structure 204. A signal input wiring structure 206 is formed on the other side of the structure 203, and a pump input wiring structure 207 is formed on the other side of the pump line structure 204; wherein, the coplanar waveguide resonator structure 203 is formed with Nb /Al-AlOx/Nb Josephson junction 208.

As an example, the method of forming the coplanar waveguide resonator structure 203 , the pump line structure 204 , the ground line structure 205 , the signal input wiring structure 206 and the pump input wiring structure 207 includes: :

3-1) The upper Nb layer 2023 is etched until the Al-AlOx layer 2022 is exposed, so as to define a Josephson junction region based on the upper Nb layer 2023 remaining after etching (that is, to define the retention after etching) The area where the upper Nb layer 2023 is located is the Josephson junction area), as shown in Figure 9;

3-2) The Al-AlOx layer 2022 is etched until the lower Nb layer 2021 is exposed, wherein the Al-AlOx layer 2022 remaining after etching is located in the Josephson junction region, as shown in FIG. 10 . Show;

3-3) The lower Nb layer 2021 is etched until the substrate 201 is exposed to form the coplanar waveguide resonator structure 203, the pump line structure 204, the ground line structure 205, the The signal input wiring structure 206 and the pump input wiring structure 207; wherein, the Josephson junction region is formed at the end of the coplanar waveguide resonator structure 203, and the Nb/Al- AlOx/Nb Josephson junction 208, as shown in FIG. 11 .

Specifically, the area of the Al-AlOx layer 2022 remaining after etching is larger than the area of the upper Nb layer 2023 remaining after etching, so as to prevent the upper Nb layer 2023 and the lower Nb layer 2021 from being damaged due to contact cause a short circuit.

In step 4), as shown in Figs. 12-13, an insulating layer 209 is formed on the upper surface of the structure in step 3), and the insulating layer 209 is etched to form the Nb/Al-AlOx/ Josephson junction vias 210 are formed on the surface of the Nb Josephson junction 208 , grounding vias 211 are formed on the surface of the ground wire structure 205 , input signal pin vias 212 are formed on the surface of the signal input wiring structure 206 , and Pump input pin vias 213 are formed on the surface of the pump input wiring structure 107 .

As an example, the material of the insulating layer 209 includes SiO ₂ . Of course, other suitable insulating materials are also applicable to this example.

In step 5), as shown in FIGS. 14-15, a superconducting thin film layer 214 is formed on the upper surface of the structure in step 4), and the superconducting thin film layer 214 is etched to The junction via hole 210 is electrically connected to the ground via hole 211 , and the ground pin 215 is formed in the ground via hole 211 , the input signal pin 216 is formed in the input signal pin via hole 212 , and the ground pin 216 is formed in the ground via hole 211 . A pump input pin 217 is formed in the pump input pin via hole 213 .

As an example, the material of the superconducting thin film layer 214 includes Nb; in this example, the same Nb as the superconducting material in the Nb/Al-AlOx/Nb laminated structure 202 is selected as the lead material, so as to improve the device performance .

As shown in FIG. 15 , this embodiment also provides a magnetic flux-driven Josephson parametric amplifier prepared based on the above preparation method, the Josephson parametric amplifier includes:

substrate 201;

A coplanar waveguide resonator structure 203 is formed on the upper surface of the substrate 201, and a Nb/Al-AlOx/Nb Josephson junction 208 is formed therein;

The pump line structure 204 is formed on the upper surface of the substrate 201 and located on one side of the coplanar waveguide resonator structure 203;

a ground wire structure 205, formed on the upper surface of the substrate 201 and located between the coplanar waveguide resonator structure 203 and the pump wire structure 204;

The signal input wiring structure 206 is formed on the upper surface of the substrate 201 and located on the other side of the coplanar waveguide resonator structure 203;

a pumping input wiring structure 207, formed on the upper surface of the substrate 201 and located on the other side of the pumping wiring structure 204;

The insulating layer 209 is formed on the coplanar waveguide resonator structure 203, the pump line structure 204, the ground line structure 205, the signal input wiring structure 206, the pump input wiring structure 207 and the A part of the upper surface of the substrate 201, and a Josephson junction via 210 is formed on the surface of the Nb/Al-AlOx/Nb Josephson junction 208, a ground via 211 is formed on the surface of the ground structure 205, An input signal pin via hole 212 is formed on the surface of the signal input wiring structure 206, and a pump input pin via hole 213 is formed on the surface of the pump input wiring structure 207;

The superconducting thin film layer 214 is formed on the Josephson junction via 210, the ground via 211, the input signal pin via 212, the pump input pin via 213 and part of the insulating layer 209 to electrically connect the Josephson junction vias 210 and the ground vias 211, and at the same time form ground pins 215 in the ground vias 211, and form the input signal pin vias 212 in the ground vias 211. An input signal pin 216 is formed in the pump input pin via hole 213 , and a pump input pin 217 is formed in the pump input pin via hole 213 .

To sum up, a magnetic flux-driven Josephson parametric amplifier and a preparation method thereof of the present invention use the existing micro-nano processing technology to etch the Nb/Al-AlOx/Nb laminated structure to form Nb/Al- The AlOx/Nb Josephson junction coplanar waveguide resonator series superconducting quantum interference instrument structure is also formed with a pump line structure, which solves the problem of the difficulty in cleaning the substrate, the existence of redundant patterns and the low superconducting transition temperature in the prior art. The performance of the Josephson parametric amplifier is greatly improved; the preparation method of the present invention is compatible with the traditional semiconductor process, and the prepared Josephson parametric amplifier can achieve a gain of 20dB, a noise temperature below 400mK, and has a good thermal cycle. , High operating temperature (can work in the liquid helium temperature region (4.2K)), good junction uniformity, easy to large-scale expansion of integrated circuits. Therefore, the present invention effectively overcomes various shortcomings in the prior art and has high industrial application value.

The above-mentioned embodiments merely illustrate the principles and effects of the present invention, but are not intended to limit the present invention. Anyone skilled in the art can modify or change the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or changes made by those with ordinary knowledge in the technical field without departing from the spirit and technical idea disclosed in the present invention should still be covered by the claims of the present invention.

Claims (8)

1. A method of making a magnetic flux driven josephson parametric amplifier, the method comprising:

1) providing a substrate;

2) forming a Nb/Al-AlOx/Nb laminated structure on the upper surface of the substrate;

3) sequentially etching an upper Nb layer, an Al-AlOx layer and a lower Nb layer in the Nb/Al-AlOx/Nb laminated structure to form a coplanar waveguide resonant cavity structure and a pumping line structure, simultaneously forming a ground wire structure between the coplanar waveguide resonant cavity structure and the pumping line structure, forming a signal input wiring structure on the other side of the coplanar waveguide resonant cavity structure, and forming a pumping input wiring structure on the other side of the pumping line structure; wherein, a Nb/Al-AlOx/Nb Josephson junction is formed in the coplanar waveguide resonant cavity structure;

4) forming an insulating layer on the upper surface of the structure obtained in the step 3), and etching the insulating layer to form a Josephson junction via hole on the surface of the Nb/Al-AlOx/Nb Josephson junction, a ground via hole on the surface of the ground wire structure, an input signal pin via hole on the surface of the signal input wiring structure, and a pumping input pin via hole on the surface of the pumping input wiring structure;

5) forming a superconducting thin film layer on the upper surface of the structure obtained in the step 4), etching the superconducting thin film layer to electrically connect the Josephson junction via hole and the ground via hole, and simultaneously forming a ground pin in the ground via hole, an input signal pin in the input signal pin via hole, and a pumping input pin in the pumping input pin via hole.

2. The method of making a magnetic flux driven josephson parametric amplifier of claim 1, further comprising: and cleaning the substrate in the step 1).

3. The method of fabricating a flux-driven josephson parametric amplifier of claim 1, wherein the method of forming the Nb/Al-AlOx/Nb laminate structure in step 2) comprises: sequentially forming a lower Nb layer and an Al layer on the upper surface of the substrate by adopting a direct current magnetron sputtering in-situ growth method, forming an AlOx layer on the surface of the Al layer by adopting a static oxidation method to obtain an Al-AlOx layer, and finally forming an upper Nb layer on the upper surface of the Al-AlOx layer by adopting the direct current magnetron sputtering in-situ growth method.

4. The method of making a magnetic flux driven josephson parametric amplifier of claim 3, wherein the thickness of the lower Nb layer is greater than its magnetic field penetration depth, the thickness of the Al layer is less than the coherence length of the lower Nb layer, the thickness of the AlOx layer is inversely proportional to the critical current density of the josephson junction, and the thickness of the upper Nb layer is greater than its magnetic field penetration depth.

5. The method of manufacturing a magnetic flux driven josephson parametric amplifier according to claim 1, wherein the method of forming the coplanar waveguide resonant cavity structure, the pump line structure, the ground line structure, the signal input wiring structure, and the pump input wiring structure in step 3) comprises:

3-1) etching the upper Nb layer until the Al-AlOx layer is exposed to define a Josephson junction region based on the upper Nb layer remaining after etching;

3-2) etching the Al-AlOx layer until the underlying Nb layer is exposed, wherein the Al-AlOx layer remaining after etching is located at the Josephson junction region;

3-3) etching the lower Nb layer until the substrate is exposed to form the coplanar waveguide resonant cavity structure, the pumping line structure, the ground line structure, the signal input wiring structure and the pumping input wiring structure; wherein the Josephson junction region is formed at an end of the coplanar waveguide resonant cavity structure and wherein the Nb/Al-AlOx/Nb Josephson junction is formed.

6. The method of making a magnetic flux driven josephson parametric amplifier according to claim 5, wherein the area of the Al-AlOx layer remaining after etching is greater than the area of the upper Nb layer remaining after etching.

7. The method of claim 1, wherein the insulating layer comprises SiO₂And the material of the superconducting thin film layer comprises Nb.

8. A flux-driven josephson parametric amplifier prepared by the preparation method of any one of claims 1 to 7, comprising:

a substrate;

a coplanar waveguide resonant cavity structure formed on the upper surface of the substrate, wherein Nb/Al-AlOx/Nb Josephson junctions are formed;

the pumping line structure is formed on the upper surface of the substrate and is positioned on one side of the coplanar waveguide resonant cavity structure;

the ground wire structure is formed on the upper surface of the substrate and is positioned between the coplanar waveguide resonant cavity structure and the pumping wire structure;

the signal input wiring structure is formed on the upper surface of the substrate and is positioned on the other side of the coplanar waveguide resonant cavity structure;

the pumping input wiring structure is formed on the upper surface of the substrate and is positioned on the other side of the pumping line structure;

an insulating layer formed on the coplanar waveguide resonant cavity structure, the pump line structure, the ground line structure, the signal input wiring structure, the pump input wiring structure and a portion of the upper surface of the substrate, and formed with a josephson junction via on the Nb/Al-AlOx/Nb josephson junction surface, a ground via on the ground line structure surface, an input signal pin via on the signal input wiring structure surface, and a pump input pin via on the pump input wiring structure surface;

a superconducting thin film layer formed on the Josephson junction via, the ground via, the input signal pin via, the pumping input pin via, and a portion of the upper surface of the insulating layer to electrically connect the Josephson junction via and the ground via, while forming a ground pin in the ground via, an input signal pin in the input signal pin via, and a pumping input pin in the pumping input pin via.

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