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CN-121985732-A - Post-preparation chemical heat treatment method of superconductive Josephson junction

CN121985732ACN 121985732 ACN121985732 ACN 121985732ACN-121985732-A

Abstract

The invention provides a post-preparation chemical heat treatment method of a high-temperature superconductive Josephson junction, which promotes migration and recombination of oxygen crystal lattice vacancies by annealing the high-temperature superconductive Josephson junction under a preset atmosphere, optimizes the microstructure of a barrier layer and repairs lattice damage in micro-nano processing to a certain extent, thereby remarkably improving the critical current of the high-temperature superconductive Josephson junction, moderately reducing normal state resistance, further improving characteristic voltage and simultaneously not changing the intrinsic transmission mechanism of the high-temperature superconductive Josephson junction. The problems that in the prior art, the defect of oxygen crystal lattice vacancies of a superconductive Josephson junction is unstable, and a transitional region with gradient change of superconductive characteristics possibly formed in the preparation process causes the characteristic voltage to be reduced, thereby influencing the performance parameters, the batch consistency and the stability of the device are solved.

Inventors

  • LIU SHAOHUA
  • LI HAO
  • WANG JI
  • YOU LIXING

Assignees

  • 中国科学院上海微系统与信息技术研究所

Dates

Publication Date
20260505
Application Date
20251224

Claims (10)

  1. 1. A post-preparation chemical heat treatment method of a high temperature superconducting josephson junction, the method comprising: providing a high temperature superconducting josephson junction comprising two superconducting electrode layers and a barrier layer between the two superconducting electrode layers; And annealing the high-temperature superconductive Josephson junction under a preset atmosphere.
  2. 2. The post-preparation chemical heat treatment method of the high-temperature superconductive Josephson junction according to claim 1, wherein the high-temperature superconductive Josephson junction is prepared based on a focused helium ion beam technology.
  3. 3. The post-preparation chemical heat treatment method of a high temperature superconductive Josephson junction according to claim 1, wherein the material of the superconductive electrode layer of the high temperature superconductive Josephson junction is copper oxide superconductor.
  4. 4. The post-preparation chemical heat treatment method of a high temperature superconductive Josephson junction according to claim 1, wherein the high temperature superconductive Josephson junction comprises a grain boundary junction or a step edge junction.
  5. 5. The post-preparation chemical heat treatment method of the high temperature superconductive Josephson junction according to claim 1, wherein the preset atmosphere is air.
  6. 6. The post-preparation chemical heat treatment method of a high temperature superconductive Josephson junction according to claim 1, wherein the method of annealing the high temperature superconductive Josephson junction in a predetermined atmosphere to promote repair of the oxygen crystal lattice vacancy defects comprises: Placing the high temperature superconductive josephson junction in a chamber of an annealing device; vacuumizing until reaching a preset vacuum degree; argon or oxygen is introduced into the cavity to purify the cavity and the gas pipeline, and the process is repeated until the purification is completed; introducing the gas of the preset atmosphere into the cavity; And annealing is carried out by adopting preset process parameters.
  7. 7. The post-preparation chemical heat treatment method of the high-temperature superconductive Josephson junction according to claim 1 or 6, wherein the process parameters of the annealing treatment comprise the annealing temperature of 80-200 ℃ and the annealing time of 5-120 min.
  8. 8. The post-preparation chemical heat treatment method of the high-temperature superconductive Josephson junction of claim 6, wherein the gas in the preset atmosphere is one of argon, oxygen and ozone.
  9. 9. The post-production chemical heat treatment method of a high temperature superconducting Josephson junction according to claim 6, wherein the vacuum degree in the chamber of the annealing device is lower than 10Pa when the annealing treatment is performed.
  10. 10. The post-preparation chemical heat treatment method of a high temperature superconductive josephson junction according to claim 1 or 6, further comprising the step of cooling the high temperature superconductive josephson junction in the preset atmosphere after annealing the high temperature superconductive josephson junction in the preset atmosphere.

Description

Post-preparation chemical heat treatment method of superconductive Josephson junction Technical Field The invention relates to the field of high-temperature superconductivity, in particular to a post-preparation chemical heat treatment method of a high-temperature superconductivity Josephson junction. Background The discovery of copper oxide high temperature superconductors breaks through the low temperature limit of the traditional superconducting materials, and the higher critical temperature (T c) significantly reduces the refrigeration cost and the system complexity, so that the high temperature superconducting electronics is regarded as a key way for pushing the superconducting devices from laboratories to large-scale application. Josephson junctions constructed with copper oxide superconductors, such as yttrium barium copper oxide (YBCO, yttrium Barium Copper Oxide), have become the core base elements of many functional devices, such as superconducting quantum interference devices, superconducting qubits, and superconducting digital circuits, whose performance directly determines the reliability and practicality of the final device. As shown in fig. 1, a high temperature superconductive josephson junction is generally formed by a superconductive electrode layer 1 at both ends and a thin barrier layer 2 in the middle, and in a superconductive state, a cooper pair 3 forms a superfluid by quantum tunneling across the barrier, which is the josephson effect. Superconducting electronic devices developed based on the effect have been widely applied to the fields of biological magnetic detection, geophysical exploration, terahertz technology and the like. The performance of the josephson junction is mainly determined by the critical current I c and the normal state resistance R n, and the product I cRn is the characteristic voltage, which affects key indexes such as the switching speed and the noise performance of the device. Taking superconducting quantum interference device (SQUID) as an example, in order to increase modulation voltage amplitude, wherein,For the reduction of the inductance by a factor,Is a boltzmann constant,In order to be able to operate at a temperature,A flux quantum) requires a larger I cRn. Said barrier layer 2 of the high temperature superconducting josephson junction is generally realized by grain boundary or local modification (e.g. ion irradiation), wherein focused helium ion beam (He-FIB) technology is one of the most potential technical routes for research hotspots and high temperature superconducting electronics practicality due to its high precision and tunability. The technology bombards the copper oxide high-temperature superconducting film through high-energy focused helium ions to generate atomic-level defects, so that the superconducting property of a bombarded area is weakened, weak connection is formed, and the high-temperature superconducting Josephson junction shown in figure 1 is formed. High quality high temperature superconductive josephson junctions present multiple challenges in the fabrication process. In the He-FIB processing process, ion bombardment can lead to the formation of a transition region with gradient variation of superconducting characteristics at the edge of an irradiation region, and a mixed transmission mechanism of quantum tunneling and proximity effect coexistence can be introduced, wherein in a proximity effect structure, the amplitude of superconducting electrons is obviously attenuated compared with that of electrode materials, so that the value of I cRn is reduced. Other micro-nano processing steps such as photoetching, ion etching and the like can damage the lattice structure, and the consistency and stability of the device are affected. These factors may lead to reduced device performance parameters (e.g., feature voltage) for He-FIB fabrication, reduced lot-to-lot consistency and stability, and thus hamper the commercial application prospect of superconducting electronics. Disclosure of Invention In view of the above-mentioned drawbacks of the prior art, an object of the present invention is to provide a post-preparation chemical heat treatment method for high-temperature superconductive josephson junction, which is used to solve the problems of unstable high-temperature superconductive josephson junction oxygen crystal lattice vacancy defects, reduced characteristic voltage in transition regions and transition regions which form gradient changes of superconductive characteristics during preparation, and further influence device performance parameters, batch consistency and stability in the prior art. To achieve the above and other related objects, the present invention provides a post-preparation chemical heat treatment method of a high temperature superconductive josephson junction, the method comprising: providing a high temperature superconducting josephson junction comprising two superconducting electrode layers and a barrier layer b