IN-SITU FABRICATION OF TL-BASED SUPERCONDUCTING THIN-FILMS BY 2-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 T l2O partial pressure on the phase formation and growth of various Tl-b ased superconducting phases were first investigated by an ex-situ two zone postannealing scheme to simulate the depsoition environ ment of s ubsequent in-situ process. The conditions obtained were then used as g uidelines for in-situ processes. The rf-sputtering system used for in- situ de position is equipped with heating facilities capable of contro lling the temperatures of the substrates and the Tl2O3 source separate ly. Preliminary results indicate that, by varying the substrate temper ature and the partial pressure of Tl2O in a similar manner, Tl-based s uperconducting phases can be obtained in-situ with properties comparab le to those obtained by two-step annealing processes.