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

Attempts to fabricate Tl-based superconducting thin films in-situ were made using a two-zone off-axis rf-sputtering method. The effects of Tl/sub 2/O partial pressure on the phase formation and growth of various Tl-based superconducting phases were first investigated by an ex-situ two zone post-annealing scheme to simulate the deposition environment of the subsequent in-situ process. The conditions obtained were then used as guidelines for in-situ processes. The rf-sputtering system used for in-situ deposition is equipped with heating facilities capable of controlling the temperatures of the substrates and the Tl/sub 2/O/sub 3/ source separately. Preliminary results indicate that, by varying the substrate temperature and the partial pressure of Tl/sub 2/O in a similar manner, Tl-based superconducting phases can be obtained in-situ with properties comparable to those obtained by two-step annealing processes.