Thin film processing for high-Tc superconductors of the Bi-system

Abstract

Basic thin film deposition processes for controlled deposition of the high-Tc superconductors of the Bi-systems are described. The layered structures of Bi-oxide superconductors are fabricated by a multitarget sputtering process. The multitarget sputtering process realizes the controlled deposition of single phase Bi-oxide superconductors, Bi2O2 · 2SrO · (n −1)CaO · nCuO2 for n = 1 to 5. The minimum thickness controlled by the multitarget sputtering is a half crystal unit-cell of around 15 Å, and the superlattices comprising (AkBk) · m, where A and B denote the Bi-oxide superconductors with different numbers of Cu–O layers, could be fabricated for k > 1, although ion mixing takes place during the sputtering deposition due to the bombardment of the highly energetic sputtered adatoms. Multitarget sputtering will be available for the fabrication of the artificially-made layered oxide superconductors (ALOS).