In-situ fabrication of Tl-based superconducting thin films by two-zone RF-sputtering

Abstract

Attempts to fabricate Tl-based superconducting thin films in-situ were made using a two-zone off-axis rf-sputtering method. The effects of Tl2O partial pressure on the phase formation and growth of various Tl-based superconducting phases were first investigated by an ex-situ two zone postannealing scheme to simulate the depsoition environ ment of subsequent in-situ process. The conditions obtained were then used as guidelines for in-situ processes. The rf-sputtering system used for in-situ de position is equipped with heating facilities capable of controlling the temperatures of the substrates and the Tl2O3 source separately. Preliminary results indicate that, by varying the substrate temperature and the partial pressure of Tl2O in a similar manner, Tl-based superconducting phases can be obtained in-situ with properties comparable to those obtained by two-step annealing processes.