Second-order Gradient Independent Input Feedback Type Superconducting Quantum Interference Device and Its Preparation Method

Abstract

The present disclosure relates to a two-step gradient independent input feedback type superconducting quantum interference device and a preparation method thereof, including: eight superconducting pads, the eight superconducting pads include four input superconducting pads and four negative feedback superconducting pads, one input superconducting pad and one negative feedback superconducting pad form a superconducting loop, and the four superconducting loops are connected in parallel and arranged in a centrosymmetric manner; an input coil, the input coil is coupled with the four superconducting input superconducting pads; a negative feedback coil, the negative feedback coil is coupled with the four negative feedback superconducting pads. The present disclosure can effectively reduce the crosstalk phenomenon between the input coil and the feedback coil, and improve the coupling coefficient and transmission efficiency of the input coil and the feedback coil.

Description

Technical Field

[0001] The present disclosure relates to the technical field of superconducting electronics, and particularly to a second-order gradient independent input feedback type superconducting quantum interference device and a preparation method thereof. Background Art

[0002] A Superconducting Quantum Interference Device (SQUID) is currently the most sensitive magnetic field sensor, and its equivalent energy resolution can approach the quantum limit level, being widely used in biomagnetic measurement and geomagnetic exploration. The current sensor based on SQUID can precisely measure signals such as tiny currents that can be equivalently converted into magnetic fluxes, and it is the only readout device for instruments such as Transition-Edge Sensor (TES), Metallic Magnetic Calorimeter (MMC), and Cryogenic Current Comparator (CCC). Therefore, as a key core device in modern large-scale scientific installations in cosmology and biomedicine, research on its preparation process, configuration design, principle theoretical simulation, and amplification readout technology is of great importance.

[0003] The noise level of the SQUID current sensor determines its measurement sensitivity and is one of the important indicators of the SQUID current sensor. Moreover, the interference of the environmental magnetic field on the SQUID loop cannot be ignored. Therefore, the second-order gradiometer type SQUID came into being. By paralleling four superconducting loops, the influence of the environmental magnetic field can be effectively reduced.

[0004] In related technologies, generally, the input coil and the feedback coil are coupled to the same superconducting gasket, and crosstalk is likely to occur between the input coil and the negative feedback coil, and the coupling coefficient and transfer efficiency of the input coil and the negative feedback coil are both low. Summary of the Invention

[0005] Based on this, it is necessary to provide a second-order gradient independent input feedback type superconducting quantum interference device and a preparation method thereof for the above technical problems, which can at least effectively reduce the crosstalk phenomenon between the input coil and the feedback coil, and improve the coupling coefficient and transfer efficiency of the input coil and the feedback coil.

[0006] To achieve the above and other objectives, in a first aspect, the present disclosure provides a second-order gradient independent input feedback type superconducting quantum interference device, including: eight superconducting pads, the eight superconducting pads include four input superconducting pads and four negative feedback superconducting pads, one input superconducting pad and one negative feedback superconducting pad form a superconducting loop, and the four superconducting loops are connected in parallel and arranged in central symmetry; an input coil, the input coil is coupled to the four superconducting input superconducting pads; a negative feedback coil, the negative feedback coil is coupled to the four negative feedback superconducting pads.

[0007] In the second-order gradient independent input feedback type superconducting quantum interference device in the above embodiment, four input superconducting pads, four negative feedback superconducting pads are formed and four superconducting loops arranged in central symmetry are composed, and the input coil is coupled to the four superconducting input superconducting pads, and the negative feedback coil is coupled to the four negative feedback superconducting pads, avoiding the crosstalk that easily occurs between the input coil and the negative feedback coil in the prior art when the input coil and the feedback coil are coupled to the same superconducting pad, and the problems that the coupling coefficient and transfer efficiency of the input coil and the negative feedback coil are relatively low, and at least can effectively reduce the crosstalk phenomenon between the input coil and the feedback coil, and improve the coupling coefficient and transfer efficiency of the input coil and the feedback coil.

[0008] In one embodiment, the input coil surrounds the four input superconducting pads and forms an input port on the horizontal symmetry line of the eight superconducting pads; the negative feedback coil surrounds the four negative feedback superconducting pads and forms a negative feedback port.

[0009] In the second-order gradient independent input feedback type superconducting quantum interference device in the above embodiment, the current to be detected is input through the input coil surrounding the four input superconducting pads, and the flux-locked working mode is realized through the negative feedback port, and the output voltage corresponding to the current to be detected can be accurately detected.

[0010] In one embodiment, the second-order gradient independent input feedback type superconducting quantum interference device further includes: a bias coil, the bias coil is connected to the four superconducting loops and forms a bias port.

[0011] In one embodiment, the bias coil includes a first Josephson junction, a second Josephson junction, a first resistor, a second resistor, and an attenuation resistor, and the first resistor and the second resistor are parallel resistors in the bias circuit.

[0012] In the second-order gradient independent input feedback type superconducting quantum interference device in the above embodiment, through the modulation effect of the two Josephson junctions, the two resistors and the attenuation resistor on the magnetic flux, the bias circuit can accurately output the detection voltage through the bias port.

[0013] In one embodiment, each input superconducting gasket includes: a substrate; a first superconducting layer located on the substrate; a first insulating layer located on the first superconducting layer; and a superconducting coil layer located on the first insulating layer.

[0014] In the two-step gradient independent input feedback type superconducting quantum interference device in the above embodiment, through the structure of the substrate, superconducting layer and insulating layer, an input superconducting gasket is formed, which can accurately capture the magnetic flux of the input loop.

[0015] In one embodiment, each negative feedback superconducting gasket includes: a substrate; a first superconducting layer located on the substrate; a first insulating layer located on the first superconducting layer; and a superconducting coil layer located on the first insulating layer.

[0016] In the two-step gradient independent input feedback type superconducting quantum interference device in the above embodiment, through the structure of the substrate, superconducting layer and insulating layer, a negative feedback superconducting gasket is formed, which can realize the flux-locked working mode of the two-step gradient independent input feedback type superconducting quantum interference device.

[0017] In one embodiment, the bias coil includes: a substrate; a first superconducting layer located on the substrate; a first insulating layer located on the first superconducting layer; a second superconducting layer located on the first insulating layer; a second insulating layer located on the second superconducting layer; a superconducting coil layer located on the second insulating layer; and a resistance layer located on the superconducting coil layer for forming a first resistor, a second resistor and an attenuation resistor; wherein, the second superconducting layer, the superconducting coil layer and the resistance layer together form the bias coil.

[0018] In the two-step gradient independent input feedback type superconducting quantum interference device in the above embodiment, the bias coil is formed by two superconducting layers and one resistance layer, which ensures the detection accuracy and sensitivity of the two-step gradient independent input feedback type superconducting quantum interference device.

[0019] In one embodiment, the first superconducting layer, the first insulating layer and the second superconducting layer form the first Josephson junction and / or the second Josephson junction.

[0020] In the two-step gradient independent input feedback type superconducting quantum interference device in the above embodiment, by forming the Josephson junction structure, a highly sensitive two-step gradient independent input feedback type superconducting quantum interference device can be formed.

[0021] In one embodiment, the winding directions of the input coil and the negative feedback coil are opposite.

[0022] Second aspect, embodiments of the present disclosure further provide a method for manufacturing a two-step gradient independent input feedback type superconducting quantum interference device, including: providing a substrate; forming a first superconducting layer on the substrate, and etching the first superconducting layer to obtain a first superconducting layer with a first target pattern; forming a first insulating layer on the first superconducting layer; forming a second superconducting layer on the first insulating layer; forming a second insulating layer on the second superconducting layer; forming a superconducting coil layer on the second insulating layer, etching the superconducting coil layer to obtain a superconducting coil layer for forming an input coil, a negative feedback coil, and a bias coil, and forming a plurality of grooves penetrating the second insulating layer in the superconducting coil layer, and depositing superconducting material in the grooves to connect the superconducting coil layer and the second superconducting layer; forming a resistance layer on the superconducting coil layer, and the resistance layer is used to form a first resistor, a second resistor, and an attenuation resistor.

[0023] In the method for manufacturing a two-step gradient independent input feedback type superconducting quantum interference device in the above embodiments, four superconducting input pads and four negative feedback superconducting pads are formed to form four superconducting loops arranged in central symmetry, and the input coil is coupled with the four superconducting input pads, and the negative feedback coil is coupled with the four negative feedback superconducting pads, avoiding the crosstalk that easily occurs between the input coil and the feedback coil in the prior art when the input coil and the feedback coil are coupled to the same superconducting pad, and the problems that the coupling coefficient and transfer efficiency between the input coil and the negative feedback coil are relatively low. At least it can effectively reduce the crosstalk phenomenon between the input coil and the feedback coil, and improve the coupling coefficient and transfer efficiency of the input coil and the feedback coil. Description of the Drawings

[0024] In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present disclosure. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0025] In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present disclosure. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0026] Figure 1 It is a schematic structural diagram of a two-step gradient independent input feedback type superconducting quantum interference device provided in an embodiment;

[0027] Figure 2 It is a schematic structural diagram of another two-step gradient independent input feedback type superconducting quantum interference device provided in an embodiment;

[0028] Figure 3 The equivalent circuit diagram of a second-order gradient independent input feedback type superconducting quantum interference device provided in an embodiment;

[0029] Figure 4 The flowchart of the preparation method of a second-order gradient independent input feedback type superconducting quantum interference device provided in an embodiment.

[0030] Explanation of reference numerals:

[0031] 1. Input superconducting gasket; 2. Input superconducting gasket; 3. Input superconducting gasket; 4. Input superconducting gasket; 5. Negative feedback superconducting gasket; 6. Negative feedback superconducting gasket; 7. Negative feedback superconducting gasket; 8. Negative feedback superconducting gasket; 9. First Josephson junction; 10. Second Josephson junction; 11. First resistor; 15. Second resistor; 12. Attenuation resistor; 13. First superconducting layer; 14. Superconducting coil layer; 201. Substrate; 202. Second superconducting layer; 203. First insulating layer; 204. Second insulating layer; 205. Resistor layer; 301. Input coil; 302. Negative feedback coil; 303. Bias coil; A. Input port; B. Negative feedback port; C. Bias port; D. Horizontal symmetry line. Detailed implementation manners

[0032] To facilitate the understanding of the present disclosure, the present disclosure will be described more comprehensively below with reference to the relevant drawings. The preferred embodiments of the present disclosure are given in the drawings. However, the present disclosure can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, these embodiments are provided to make the disclosure of the present disclosure more thorough and comprehensive.

[0033] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present disclosure belongs. The terms used in the description of the present disclosure herein are only for the purpose of describing specific embodiments and are not intended to limit the present disclosure.

[0034] It should be understood that when an element or layer is referred to as being "on", "adjacent to", "connected to", or "coupled to" another element or layer, it can be directly on, adjacent to, connected to, or coupled to the other element or layer, or intervening elements or layers may be present. In contrast, when an element is referred to as being "directly on", "directly adjacent to", "directly connected to", or "directly coupled to" another element or layer, there are no intervening elements or layers. It should be understood that although the terms first, second, third, etc. may be used to describe various elements, components, regions, layers, doping types, and / or portions, these elements, components, regions, layers, doping types, and / or portions should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer, doping type, or portion from another element, component, region, layer, doping type, or portion. Thus, without departing from the teachings of the present disclosure, the first element, component, region, layer, doping type, or portion discussed below may be denoted as the second element, component, region, layer, or portion; for example, the first doping type may be referred to as the second doping type, and similarly, the second doping type may be referred to as the first doping type; the first doping type and the second doping type are different doping types, for instance, the first doping type may be P-type and the second doping type may be N-type, or the first doping type may be N-type and the second doping type may be P-type.

[0035] Spatial relationship terms such as "under", "below", "beneath", "underneath", "above", "over", etc. are used herein to describe the relationship of one element or feature shown in the figures to other elements or features. It should be understood that, in addition to the orientation shown in the figures, spatial relationship terms also encompass different orientations of the device in use and operation. For example, if the device in the figures is flipped, an element or feature described as "under" or "beneath" or "underneath" another element or feature will be oriented "above" the other element or feature. Thus, the exemplary terms "under" and "beneath" can include both an upper and a lower orientation. Additionally, the device may also include additional orientations (such as a 90-degree rotation or other orientations), and the spatial descriptors used herein are to be interpreted accordingly.

[0036] As used herein, the singular forms "a", "an", and "the" may also include the plural forms unless the context clearly dictates otherwise. It should also be understood that when the terms "comprise" and / or "include" are used in this specification, the presence of features, integers, steps, operations, elements, and / or components can be ascertained, but one or more other features, integers, steps, operations, elements, components, and / or groups are not precluded from existence or addition. Also, as used herein, the term "and / or" includes any and all combinations of the associated listed items.

[0037] Embodiments of the invention are described herein with reference to cross-sectional views that are schematic illustrations of ideal embodiments (and intermediate structures) of the present disclosure, so that variations in the shapes shown are to be expected, for example, due to manufacturing techniques and / or tolerances. Thus, embodiments of the present disclosure should not be limited to the specific shapes of regions shown herein, but include shape deviations due to, for example, manufacturing techniques. For example, an implantation region shown as rectangular will typically have rounded or curved features at its edges and / or an implantation concentration gradient, rather than a binary change from the implantation region to the non-implantation region. Similarly, a buried region formed by implantation can result in some implantation in the region between the buried region and the surface through which the implantation occurs. Thus, the regions shown in the figures are substantially schematic, and their shapes do not represent the actual shapes of the regions of the device and do not limit the scope of the present disclosure.

[0038] Please refer to Figures 1 - 3 It should be noted that the illustrations provided in this embodiment only schematically illustrate the basic concept of the present application. The illustrations only show the components related to the present application and are not drawn according to the number, shape, and size of the components in actual implementation. The types, quantities, and proportions of the components in actual implementation can be arbitrarily changed, and the component layout type may also be more complex.

[0039] Please refer to Figure 3 , Figure 3 is an equivalent circuit diagram of a two-step gradient independent input feedback type superconducting quantum interference device provided in an embodiment. It should be noted that a SQUID (superconducting quantum interference device) is an extremely sensitive magnetic field sensor based on superconductors and Josephson junctions. It uses the quantum interference effect to detect extremely weak magnetic field changes and is widely used in fields such as physics research, medical imaging, and geological exploration. A SQUID consists of two Josephson junctions connected in parallel on a superconducting loop. The superconducting loop (Superconducting Loop) is used to capture and measure magnetic flux. The two parallel Josephson junctions respond to changes in magnetic flux through the Josephson effect and the flux quantization effect.

[0040] As Figure 3 shown in, the superconducting loop can capture the current input by the input coil 301. The negative feedback port B is used to implement the flux-locked operating mode, and the bias port C is used to input a bias current to make the superconducting quantum interference device work properly, thereby achieving high-precision detection and measurement of the input tiny current.

[0041] Please continue to refer to Figure 1, As an example, one aspect of the present application provides a schematic structural diagram of a second-order gradient independent input feedback type superconducting quantum interference device, including: eight superconducting pads, where the eight superconducting pads include four input superconducting pads and four negative feedback superconducting pads. One input superconducting pad and one negative feedback superconducting pad form a superconducting loop, and the four superconducting loops are arranged in central symmetry; an input coil 301, which is coupled to the four superconducting input superconducting pads; and a negative feedback coil 302, which is coupled to the four negative feedback superconducting pads.

[0042] Please continue to refer to Figure 1 , Figure 1 The input superconducting pad 1, input superconducting pad 2, input superconducting pad 3, and input superconducting pad 4 in Figure 1 are the four input superconducting pads, and the negative feedback superconducting pad 5, negative feedback superconducting pad 6, negative feedback superconducting pad 7, and negative feedback superconducting pad 8 in

[0043] are the four input superconducting pads.

[0044] Among them, an input superconducting pad 1 and a negative feedback superconducting pad 5 form a superconducting loop, an input superconducting pad 2 and a negative feedback superconducting pad 6 form a superconducting loop, an input superconducting pad 3 and a negative feedback superconducting pad 7 form a superconducting loop, and an input superconducting pad 4 and a negative feedback superconducting pad 8 form a superconducting loop.

[0044] Here, as shown in Figure 1 , one input superconducting pad and one negative feedback superconducting pad in each superconducting loop are superconducting-connected.

[0045] Among them, as shown in Figure 1 , the four superconducting loops are arranged in central symmetry, and the four input superconducting pads are also arranged in central symmetry, and the four negative feedback superconducting pads are also arranged in central symmetry.

[0046] Among them, as shown in Figure 1 , the superconducting coil layer 14 surrounding the four input superconducting pads is the input coil 301, and the input coil 301 is coupled to the four superconducting input superconducting pads.

[0047] Here, it should be noted that Figure 1 the position of the input coil 301 in

[0048] is only an example, and the present application does not limit the position of the input coil 301. Those skilled in the art can adjust the position of the input coil 301 according to needs. For example, the number of turns and the diameter of the input coil can be increased or decreased. Figure 1 Among them, as shown in

[0049] Here, it should be noted that Figure 1 The position of the negative feedback coil 302 in

[0049] is only an example. The present application does not limit the position of the negative feedback coil 302. Those skilled in the art can adjust the position of the negative feedback coil 302 according to needs. For example, increase or decrease the number of turns and diameter of the coil.

[0050] In the two - step gradient independent input feedback type superconducting quantum interference device in the above - mentioned embodiment, four input superconducting pads and four negative feedback superconducting pads are formed to form four superconducting loops arranged in central symmetry. The input coil 301 is coupled with the four input superconducting pads, and the negative feedback coil 302 is coupled with the four negative feedback superconducting pads, avoiding the crosstalk that easily occurs between the input coil 301 and the negative feedback coil 302 in the prior art when the input coil 301 and the feedback coil are coupled to the same superconducting pad, and the problems of relatively low coupling coefficient and transfer efficiency between the input coil 301 and the negative feedback coil 302. It can at least effectively reduce the crosstalk phenomenon between the input coil 301 and the feedback coil, and improve the coupling coefficient and transfer efficiency of the input coil 301 and the feedback coil.

[0051] Specifically, please continue to refer to Figure 1 , the input coil 301 surrounds the four input superconducting pads and forms an input port A on the horizontal symmetry line D of the eight superconducting pads; the negative feedback coil 302 surrounds the four negative feedback superconducting pads and forms a negative feedback port B.

[0052] In the two - step gradient independent input feedback type superconducting quantum interference device in the above - mentioned embodiment, the current to be detected is input through the input coil 301 surrounding the four input superconducting pads, the flux - locked working mode is realized through the negative feedback port B, and the bias current is input through the bias port C, so that the superconducting quantum interference device can accurately detect the voltage of the current to be detected.

[0053] Please continue to refer to Figure 1 , the two - step gradient independent input feedback type superconducting quantum interference device further includes: a bias coil, the bias coil is connected to the four superconducting loops and forms a bias port C.

[0054] Please continue to refer to Figure 1 , the bias coil includes a first Josephson junction 9, a second Josephson junction 10, a first resistor 11, a second resistor 15, and an attenuation resistor 12. The first resistor 11 and the second resistor 15 are parallel resistors in the bias circuit.

[0055] In the two - step gradient independent input feedback type superconducting quantum interference device in the above - mentioned embodiment, through the modulation effect of the two Josephson junctions, the two resistors and the attenuation resistor 12 on the magnetic flux, the bias coil can accurately output a detection voltage through the bias port C.

[0056] Please refer to Figure 1 and Figure 2 Each input superconducting gasket includes: a substrate 201; a first superconducting layer 13 located on the substrate 201; a first insulating layer 203 located on the first superconducting layer 13; and a superconducting coil layer 14 located on the first insulating layer 203.

[0057] As an example, please continue to refer to Figure 1 The superconducting coil layer 14 first winds around most of a circle on the input superconducting gasket 1, then winds around one circle on the input superconducting gasket 2, then winds around a small part of a circle on the input superconducting gasket 1, then winds around most of a circle on the input superconducting gasket 3, then winds around one circle on the input superconducting gasket 4, then winds around a small part of a circle on the input superconducting gasket 3, and finally forms two input ports of the input port A through the first superconducting layer 13 and the superconducting coil layer 14.

[0058] Specifically, please continue to refer to Figure 1 When the input coil 301 crosses, it needs to borrow the second superconducting layer 202 to form a crossing of the input coil 301. As an example, when winding around most of a circle on the input superconducting gasket 3 and then winding around one circle on the input superconducting gasket 4, it needs to cross the second superconducting layer 202 once. At this time, two grooves penetrating the second insulating layer 204 ( Figure 1 the black dots in the superconducting coil layer 14 in

[0059] In the two-step gradient independent input feedback type superconducting quantum interference device in the above embodiment, an input superconducting loop is formed through the structure of the substrate 201, the superconducting layer and the insulating layer, and the magnetic flux of the input loop can be accurately captured.

[0060] In one of the embodiments, each negative feedback superconducting gasket includes: a substrate 201; a first superconducting layer 13 located on the substrate 201; a first insulating layer 203 located on the first superconducting layer 13; and a superconducting coil layer 14 located on the first insulating layer 203.

[0061] Here, it should be noted that through steps such as deposition and etching, the second superconducting layer only exists within the Josephson junction structure, and the second superconducting layer does not need to be formed in the superconducting gasket. That is to say, the second superconducting layer is only used to form the Josephson junction structure, and the second superconducting layer does not need to be formed between the superconducting gasket and the coil.

[0062] As an example, please continue to refer to Figure 1, the superconducting coil layer 14 first wraps half a turn around the negative feedback superconducting gasket 8, then wraps a little more than half a turn around the negative feedback superconducting gasket 7, then wraps more than half a turn around the negative feedback superconducting gasket 5, then wraps one turn around the negative feedback superconducting gasket 6, then wraps a little more than half a turn around the negative feedback superconducting gasket 5, then wraps more than half a turn around the negative feedback superconducting gasket 7, then wraps half a turn around the negative feedback superconducting gasket 8, and finally forms two negative feedback ports of the negative feedback port B with the superconducting coil layer 14 through the first superconducting layer 13.

[0063] Specifically, please continue to refer to Figure 1 , when the negative feedback coil 302 crosses, it needs to borrow the second superconducting layer 202 to form the crossing of the negative feedback coil 302. As an example, when wrapping half a turn around the negative feedback superconducting gasket 8 and then wrapping more than half a turn around the negative feedback superconducting gasket 7, it needs to cross the superconducting coil layer 14 once. At this time, two grooves penetrating the second insulating layer 204 ( Figure 1 the black dots in the superconducting coil layer 14 in

[0064] In the two-step gradient independent input feedback type superconducting quantum interference device in the above embodiment, through the structure of the substrate 201, superconducting layer and insulating layer, a negative feedback superconducting loop is formed, which can accurately adjust the magnetic flux of the two-step gradient independent input feedback type superconducting quantum interference device.

[0065] In one of the embodiments, the bias coil 303 includes: a substrate 201; a first superconducting layer 13 located on the substrate 201; a first insulating layer 203 located on the first superconducting layer 13; a second superconducting layer 202 located on the insulating layer; a second insulating layer 204 located on the second superconducting layer 202; a superconducting coil layer 14 located on the second insulating layer 204; and a resistance layer 205 located on the superconducting coil layer 14 for forming the first resistor 11, the second resistor 15 and the attenuation resistor 12; wherein, the second superconducting layer 202, the superconducting coil layer 14 and the resistance layer 205 together form the bias coil 303.

[0066] In the two-step gradient independent input feedback type superconducting quantum interference device in the above embodiment, the bias coil 303 is formed by two superconducting layers and one resistance layer 205, which ensures the detection accuracy and sensitivity of the two-step gradient independent input feedback type superconducting quantum interference device.

[0067] In one of the embodiments, the first superconducting layer 13, the first insulating layer 203 and the second superconducting layer 202 form the first Josephson junction 9 and / or the second Josephson junction 10.

[0068] In the two - step gradient independent input feedback type superconducting quantum interference device in the above - mentioned embodiments, by forming a superconducting loop structure with a double Josephson junction, a two - step gradient independent input feedback type superconducting quantum interference device with high sensitivity can be formed.

[0069] Among them, the winding directions of the input coil 301 and the negative feedback coil 302 are opposite.

[0070] Please refer to Figure 4 , as an example, the embodiments of the present disclosure provide a method for manufacturing a two - step gradient independent input feedback type superconducting quantum interference device, including the following steps:

[0071] Step S1000: Provide a substrate 201.

[0072] Among them, the substrate 201 can be made of semiconductor material or insulating material. The substrate 201 can be a single - layer structure or a multi - layer structure. For example, the substrate 201 can be a silicon substrate 201, a silicon dioxide substrate 201, etc., or, for another example, the substrate 201 can be a layered substrate 201 including, for example, silicon / silicon carbide, silicon - on - insulator or silicon germanium - on - insulator. Therefore, the type of the substrate 201 should not limit the protection scope of the present disclosure.

[0073] Step S2000: Form a first superconducting layer 13 on the substrate 201, and etch the first superconducting layer 13 to obtain the first superconducting layer 13 with a first target pattern.

[0074] Among them, the first superconducting layer 13 is also the (Bottom Electrode, BE layer), that is, the superconducting thin - film layer.

[0075] Specifically, the material of the first superconducting layer 13 is polycrystalline niobium (Nb).

[0076] As an example, magnetron sputtering can be used to deposit and etch the corresponding pattern (for example, the method of using a positive mask + positive photoresist can be used).

[0077] Among them, the thickness of the first superconducting layer 13 can be 100 nm to 200 nm.

[0078] As an example, the thickness of the first superconducting layer 13 can be 100 nm, 130 nm, 155 nm, 180 nm or 200 nm, etc.

[0079] Step S3000: Form a first insulating layer 203 on the first superconducting layer 13.

[0080] Among them, the first insulating layer 203 is used to form the channel layer of the Josephson junction.

[0081] Specifically, the material of the first insulating layer 203 is aluminum oxide ( )

[0082] As an example, corresponding patterns can be etched by ion beam after anodic oxidation (for example, the method of using a positive mask + positive photoresist can be used).

[0083] Among them, the thickness of the first insulating layer 203 can be 9 nm - 11 nm.

[0084] As an example, the thickness of the first insulating layer 203 can be 9 nm, 10 nm, 11 nm, and so on.

[0085] Step S4000: Form a second superconducting layer 202 on the first insulating layer 203.

[0086] Specifically, the material of the second superconducting layer 202 is polycrystalline niobium (Nb).

[0087] As an example, magnetron sputtering can be used to deposit and etch corresponding patterns (for example, the method of using a positive mask + positive photoresist can be used).

[0088] Among them, the thickness of the second superconducting layer 202 can be 100 nm to 200 nm.

[0089] As an example, the thickness of the second superconducting layer 202 can be 100 nm, 110 nm, 130 nm, 170 nm, 190 nm, 200 nm, and so on.

[0090] Step S5000: Form a second insulating layer 204 on the second superconducting layer 202.

[0091] Specifically, the material of the first insulating layer 203 is silicon oxide ( )

[0092] As an example, chemical vapor deposition can be used to deposit and etch corresponding patterns (for example, the method of using a negative mask + positive photoresist can be used).

[0093] Among them, the thickness of the first superconducting layer 13 can be 350 nm - 370 nm.

[0094] As an example, the thickness of the first superconducting layer 13 can be 350 nm, 355 nm, 360 nm, 370 nm, and so on.

[0095] Step S6000: Form a superconducting coil layer 14 on the second insulating layer 204, etch the superconducting coil layer 14 to obtain a superconducting coil layer 14 for forming an input coil 301, a negative feedback coil 302, and a bias coil 303, and form a plurality of grooves penetrating the second insulating layer 204 in the superconducting coil layer 14, and superconducting materials are deposited in the grooves to connect the superconducting coil layer 14 and the second superconducting layer 202.

[0096] Specifically, the material of the superconducting coil layer 14 is polycrystalline niobium (Nb).

[0097] As an example, magnetron sputtering can be used for deposition and ion beam etching to form the corresponding pattern (for example, the method of using a positive mask + positive photoresist can be used).

[0098] Among them, the thickness of the first superconducting layer 13 can be 390 nm - 410 nm.

[0099] As an example, the thickness of the first superconducting layer 13 can be 390 nm, 395 nm, 400 nm, or 410 nm, etc.

[0100] Step S7000: Form a resistance layer 205 on the superconducting coil layer 14.

[0101] Specifically, the material of the resistance layer 205 can be a PdAu thin film, etc.

[0102] As an example, electron beam evaporation can be used for deposition and etching to form the corresponding pattern (for example, the method of using a positive mask + positive photoresist can be used).

[0103] Among them, the thickness of the resistance layer 205 can be 50 nm - 500 nm.

[0104] As an example, the thickness of the resistance layer 205 can be 50 nm, 100 nm, 150 nm, 300 nm, 400 nm, or 500 nm, etc.

[0105] Among them, the resistance layer 205 is used to form the first resistor 11, the second resistor 15, and the attenuation resistor 12.

[0106] In the preparation method of the two-step gradient independent input feedback type superconducting quantum interference device in the above embodiments, four input superconducting pads and four negative feedback superconducting pads are formed to form four superconducting loops arranged in central symmetry, and the input coil is coupled with the four input superconducting pads, and the negative feedback coil is coupled with the four negative feedback superconducting pads, avoiding the problem that in the prior art, the input coil and the feedback coil are coupled to the same superconducting pad, and there is an easy crosstalk between the input coil and the negative feedback coil, and the coupling coefficient and transfer efficiency of the input coil and the negative feedback coil are both relatively low. It can at least effectively reduce the crosstalk phenomenon between the input coil and the feedback coil, and improve the coupling coefficient and transfer efficiency of the input coil and the feedback coil.

[0107] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features of the above embodiments are described. However, as long as the combination of these technical features does not conflict, it should be considered to be within the scope described in this specification.

[0108] The above embodiments merely represent several implementation manners of the present disclosure. The description thereof is relatively specific and detailed, but it should not be construed as a limitation to the scope of the patent application. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present disclosure, several modifications and improvements can still be made, and these all fall within the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure patent shall be subject to the appended claims.

Claims

1. A two-step gradient independent input feedback type superconducting quantum interference device, characterized in that, Comprising: Eight superconducting gaskets, the eight superconducting gaskets including four input superconducting gaskets and four negative feedback superconducting gaskets, one input superconducting gasket and one negative feedback superconducting gasket forming a superconducting loop, and the four superconducting loops being connected in parallel and arranged in central symmetry; An input coil, the input coil being coupled to the four input superconducting gaskets; A negative feedback coil, the negative feedback coil being coupled to the four negative feedback superconducting gaskets; Further comprising: A bias coil, the bias coil being connected to the four superconducting loops and forming a bias port; Wherein, each input superconducting gasket and each negative feedback superconducting gasket include a substrate, a first superconducting layer, a first insulating layer and a superconducting coil layer which are sequentially stacked along a first direction, and the first direction is the direction perpendicular to the substrate; Wherein, the input coil, the negative feedback coil and the bias coil are formed after etching the superconducting coil layer.

2. The two-step gradient independent input feedback type superconducting quantum interference device according to claim 1, wherein The input coil surrounds the four input superconducting gaskets and forms an input port on the horizontal symmetry line of the eight superconducting gaskets; The negative feedback coil surrounds the four negative feedback superconducting gaskets and forms a negative feedback port.

3. The two-step gradient independent input feedback type superconducting quantum interference device according to claim 2, wherein The bias coil includes a first Josephson junction, a second Josephson junction, a first resistor, a second resistor and an attenuation resistor, and the first resistor and the second resistor are parallel resistors in the bias coil.

4. The two-step gradient independent input feedback type superconducting quantum interference device according to claim 3, wherein The bias coil includes: A substrate; A first superconducting layer, located on the substrate; A first insulating layer, located on the first superconducting layer; A second superconducting layer, located on the first insulating layer; A second insulating layer, located on the second superconducting layer; A superconducting coil layer, located on the second insulating layer; A resistor layer, located on the superconducting coil layer and used for forming the first resistor, the second resistor and the attenuation resistor; Wherein, the second superconducting layer, the superconducting coil layer and the resistor layer jointly form the bias coil.

5. The second-order gradient independent input feedback type superconducting quantum interference device according to claim 4, characterized in that, The first superconducting layer, the first insulating layer and the second superconducting layer form the first Josephson junction and / or the second Josephson junction.

6. The two-step gradient independent input feedback type superconducting quantum interference device according to claim 1, wherein The surrounding directions of the input coil and the negative feedback coil are opposite.

7. A preparation method of a second-order gradient independent input feedback type superconducting quantum interference device, characterized in that Comprising: Providing a substrate; Forming a first superconducting layer on the substrate and etching the first superconducting layer to obtain a first superconducting layer with a first target pattern; Forming a first insulating layer on the first superconducting layer; Forming a second superconducting layer on the first insulating layer; Forming a second insulating layer on the second superconducting layer; Forming a superconducting coil layer on the second insulating layer, etching the superconducting coil layer to obtain a superconducting coil layer for forming the input coil, the negative feedback coil and the bias coil, and forming a plurality of grooves penetrating the second insulating layer in the superconducting coil layer, and depositing superconducting materials in the grooves for connecting the superconducting coil layer and the second superconducting layer; Forming a resistor layer on the superconducting coil layer, and the resistor layer is used for forming the first resistor, the second resistor and the attenuation resistor; Among them, the second-order gradient independent input feedback type superconducting quantum interference device includes: eight superconducting pads, and the eight superconducting pads include four input superconducting pads and four negative feedback superconducting pads. One input superconducting pad and one negative feedback superconducting pad form a superconducting loop, and the four superconducting loops are connected in parallel and arranged in central symmetry; An input coil, which is coupled with the four input superconducting pads; A negative feedback coil, which is coupled with the four negative feedback superconducting pads; It further includes: A bias coil, which is connected to the four superconducting loops and forms a bias port.

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