Optimization of glow discharge magnetron sputtering for deposition of high Tc superconducting thin films
Optimization of glow discharge magnetron sputtering for deposition of high Tc superconducting thin films
For in-situ deposition of BSCCO thin films at substrate temperatures around 750°C, a new spatial sputter deposition configuration with two separate sources was developed. The method regulates the film composition via simultaneous deposition from two ceramic targets; a fixed one with stoichiometric composition and one flexibly positioned with a high concentration of bismuth and copper. The accessory target, enabled compensation for the lack of the Bi and Cu from less than 10% up to the stoichmetric value. The films deposited from two sources simultaneously had a more even thickness distribution, uniform composition and much lower resistivity at room temperature. They needed a shorter time for post annealing compared to those deposited at low substrate temperatures with a single target.
The superconducting transition temperature Tc, in good films was as high as 100K, with zero resistivity values between 45K and 75K, depending on the substrate material and annealing conditions. The zero resistance transition temperature Tczero, and their resistivity variation with temperature, were found to be influenced by the heat treatment procedures. Deposition of superconducting films at temperatures > 600°C, onto different polycrystalline substrate materials always showed a degree of preferred orientation, with the c-axis perpendicular to the substrate. The films deposited at substrate temperatures around 750°C onto MgO single crystal substrates were found to be more preferentially oriented.
Film-substrate interactions were studied and a variety of buffer layers were tested. Several new stabilized substrates were sintered from binary oxide solid solution; MgO:CaO, MgO:ZrO2, ZrO2:Y2O3, and ZrO2:CaO. As-grown thin film deposited onto these substrates at temperatures of 750° and above, had a mirror like appearance and a low resistivity at room temperature. The films developed superconductivity after heat treatment for just a few minutes at temperatures close to 847°C.
University of Southampton
1996
Ramezani-Namin, Mehrdad
(1996)
Optimization of glow discharge magnetron sputtering for deposition of high Tc superconducting thin films.
University of Southampton, Doctoral Thesis.
Record type:
Thesis
(Doctoral)
Abstract
For in-situ deposition of BSCCO thin films at substrate temperatures around 750°C, a new spatial sputter deposition configuration with two separate sources was developed. The method regulates the film composition via simultaneous deposition from two ceramic targets; a fixed one with stoichiometric composition and one flexibly positioned with a high concentration of bismuth and copper. The accessory target, enabled compensation for the lack of the Bi and Cu from less than 10% up to the stoichmetric value. The films deposited from two sources simultaneously had a more even thickness distribution, uniform composition and much lower resistivity at room temperature. They needed a shorter time for post annealing compared to those deposited at low substrate temperatures with a single target.
The superconducting transition temperature Tc, in good films was as high as 100K, with zero resistivity values between 45K and 75K, depending on the substrate material and annealing conditions. The zero resistance transition temperature Tczero, and their resistivity variation with temperature, were found to be influenced by the heat treatment procedures. Deposition of superconducting films at temperatures > 600°C, onto different polycrystalline substrate materials always showed a degree of preferred orientation, with the c-axis perpendicular to the substrate. The films deposited at substrate temperatures around 750°C onto MgO single crystal substrates were found to be more preferentially oriented.
Film-substrate interactions were studied and a variety of buffer layers were tested. Several new stabilized substrates were sintered from binary oxide solid solution; MgO:CaO, MgO:ZrO2, ZrO2:Y2O3, and ZrO2:CaO. As-grown thin film deposited onto these substrates at temperatures of 750° and above, had a mirror like appearance and a low resistivity at room temperature. The films developed superconductivity after heat treatment for just a few minutes at temperatures close to 847°C.
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Published date: 1996
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Local EPrints ID: 459614
URI: http://eprints.soton.ac.uk/id/eprint/459614
PURE UUID: 4ef5cb02-8bba-43ab-b699-edd6497d9855
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Date deposited: 04 Jul 2022 17:15
Last modified: 04 Jul 2022 17:15
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Author:
Mehrdad Ramezani-Namin
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