Reduced thermal budget processing of Y-Ba-Cu-O films by rapid isothermal processing assisted metalorganic chemical vapor deposition

Abstract

Metalorganic chemical vapor deposition (MOCVD) has the potential of emerging as a viable technique to fabricate ribbons, tapes, coated wires, and the deposition of films of high‐temperature superconductors, and related materials. As a reduced thermal budget processing technique, rapid isothermal processing (RIP) based on incoherent radiation as the source of energy can be usefully coupled to conventional MOCVD. In this paper we report on the deposition and characterization of high quality superconducting thin films of Y‐Ba‐Cu‐O (YBCO) on yttrium stabilized zirconia substrates by RIP assisted MOCVD. Using O₂ gas as the source of oxygen, YBCO films deposited initially at 600 °C for 1 min and at 745 °C for 25 min followed by deposition at 780 °C for 45 s are primarily c‐axis oriented and zero resistance is observed at 89–90 K. The zero magnetic field current density at 53 and 77 K are 1.2×10⁶ and 3×10⁵ A/cm², respectively. By using a mixture of N₂O and O₂ as the oxygen source substrate temperature was further reduced in the deposition of YBCO films. The films deposited initially at 600 °C for 1 min and than at 720 °C for 30 min are c‐axis oriented and with zero resistance being observed at 91 K. The zero magnetic field current densities at 53 and 77 K are 3.4×10⁶ and 1.2×10⁶ A/cm², respectively. To the best of our knowledge this is the highest value of critical current density, J_c for films deposited by MOCVD at a substrate temperature as low as 720 °C. It is envisioned that high energy photons from the incoherent light source and the use of a mixture of N₂O and O₂ as the oxygen source, assist chemical reactions and lower overall thermal budget for processing of these films.