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Method for preparing magnesium diboride superconducting thin film by electron beam annealing

A technology of electron beam annealing and magnesium diboride, which is applied in the manufacture/processing of superconductor devices, can solve the problems of unfavorable high-quality superconducting thin films, high Mg vapor pressure, and formation of impurities, and achieve high annealing efficiency and heating and cooling speed Fast and reduce the effect of volatilization

Inactive Publication Date: 2011-10-12
INST OF ELECTRICAL ENG CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, the annealing time required by these processes is from several minutes to more than ten minutes, and the following problems are encountered in the preparation process: the high volatility of Mg requires a higher Mg vapor pressure during the film growth process; the active chemical properties of Mg It makes it easy for Mg atoms to react with other substances, especially oxygen atoms, to form impurities; too high temperature can easily cause MgB 2 Decomposition, etc.
Too high heat treatment temperature or too long heat treatment time will cause excessive magnesium volatilization, oxidation and MgB 2 decomposition, resulting in the eventual growth of MgB 2 The film contains high borides due to the lack of Mg, which is not conducive to the formation of high-quality superconducting films

Method used

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  • Method for preparing magnesium diboride superconducting thin film by electron beam annealing
  • Method for preparing magnesium diboride superconducting thin film by electron beam annealing
  • Method for preparing magnesium diboride superconducting thin film by electron beam annealing

Examples

Experimental program
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Effect test

Embodiment 1

[0024] Electron beam annealing was carried out on a self-made EBW-6 electron beam welding machine. Pioneer film is That is, N=1, the film thickness is 20nm, the size of the precursor film is 10.0mm×3.0mm, and the substrate is SiC.

[0025] 1. Place the bare substrate SiC with the same size as the precursor film on the movable workpiece stage in the sample chamber of the electron beam processing equipment. When the vacuum degree of the sample chamber is higher than 1.0×10 -2 Pa, continue to operate as follows;

[0026] 2. According to the formula in step 2, the effective penetration depth R=23nm of the electrons accelerated by the 1kV voltage in the precursor film is obtained, which is greater than the thickness of the sample film of 20nm, so the electron beam acceleration voltage U=1kV is selected;

[0027] 3. Select beam current I and beam spot size Ф: load accelerating voltage U = 1kV, adjust electron beam current I, and adjust beam spot diameter Ф at the same time, when ...

Embodiment 2

[0031] Electron beam annealing was carried out on a self-made EBW-6 electron beam welding machine. Pioneer film is That is, N=5, the film thickness is 100 nm, the size of the precursor film is 10.0 mm×3.0 mm, and the substrate is SiC.

[0032] 1. Place the bare substrate SiC with the same size as the precursor film on the movable workpiece stage in the sample chamber of the electron beam processing equipment, and vacuum the sample chamber to a vacuum degree higher than 1.0×10 -2 Pa;

[0033]2. According to the formula in step 2, the effective penetration depth R=4394nm of the electrons accelerated by the 20kV voltage in the precursor film is obtained, which is greater than the thickness of the sample film of 100nm, so the electron beam acceleration voltage U=20kV is selected;

[0034] 3. Select I=16.0mA, Ф=12.0mm;

[0035] 4. Select the annealing time t=0.14s;

[0036] 5. Place the precursor film on the movable workpiece stage in the sample chamber of the electron beam pr...

Embodiment 3

[0038] Electron beam annealing was carried out on a self-made EBW-6 electron beam welding machine. Pioneer film is That is, N=5, the film thickness is 100 nm, the size of the precursor film is 10.0 mm×3.0 mm, and the substrate is Si.

[0039] 1. Place the bare substrate SiC with the same size as the precursor film on the movable workpiece stage in the sample chamber of the electron beam processing equipment, and vacuum the sample chamber to a vacuum degree higher than 1.0×10 -2 Pa;

[0040] 2. With embodiment two, select U=20kV;

[0041] 3. Select I=2.0mA, Ф=8.0mm;

[0042] 4. Select the annealing time t=0.32s;

[0043] 5. Put the precursor film on the movable workpiece stage in the sample chamber of the electron beam processing equipment, set U=20kV, I=2.0mA, Ф=8.0mm. Since the length of the precursor film is 10 mm greater than the diameter of the beam spot of 8 mm, the moving workpiece table is moved so that the precursor film passes directly under the beam spot at a u...

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Abstract

The invention relates to a method for preparing a magnesium diboride superconducting thin film by electron beam annealing. The method is characterized by annealing a magnesium diboride forerunner film in vacuum by adopting an electron beam, enabling a magnesium and boron simple substance in the forerunner film in the annealing time of the order of magnitude of seconds to perform chemical reaction, and generating the magnesium diboride superconducting thin film finally; and determining electron beam parameters and annealing time according to different thicknesses of the forerunner film and annealing temperatures in annealing, and finishing the annealing of thin films of different thicknesses through controlling energy and dosage of the electron beam accurately. The magnesium diboride superconducting thin film prepared by using the method in the invention has the advantages of stable performances, flat surface, higher transformation temperature than 35k, uniform annealing, and the method for preparing the film has high efficiency, and is simple in operation and the like, and can be used for the preparation of a plurality of functional thin films.

Description

technical field [0001] The invention relates to a method for preparing a superconducting thin film, in particular to a periodic structure The multilayer film is a pioneer film, and the method for preparing a magnesium diboride superconducting thin film by electron beam annealing technology. Background technique [0002] Since the discovery of magnesium diboride superconductors with a critical transition temperature of 39K by Akimitsu et al. in Japan in January 2001 (Nature 410 (2001) 63), scientists from various countries have conducted a lot of research on magnesium diboride superconducting materials. MgB 2 The superconducting film is MgB 2 An important basis for the application of superconducting materials in the field of electronics, scientists from various countries have studied MgB 2 The preparation and research of superconducting thin films have given great attention, actively exploring various methods to prepare high-quality MgB 2 superconducting thin film. Af...

Claims

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Application Information

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IPC IPC(8): H01L39/24
Inventor 孔祥东韩立薛虹初明璋李建国林云生方光荣
Owner INST OF ELECTRICAL ENG CHINESE ACAD OF SCI
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