Title :
Dependence of critical temperature and resistivity of thin film Nb47wt%Ti on magnetron sputtering conditions
Author :
Hawes, C.D. ; Cooley, L.D. ; Larbalestier, D.C.
Author_Institution :
Appl. Supercond. Center, Wisconsin Univ., Madison, WI, USA
fDate :
6/1/1999 12:00:00 AM
Abstract :
Niobium-titanium multilayers generally have depressed critical temperature, T/sub c/. In this paper the variation of T/sub c/ and resistivity of magnetron sputtered Nb47wt%Ti thin films is studied as a function of the cathode power and target usage. The data are compared with analyses by Auger and scanning electron microscopy. Films made using a new target have properties which are similar to those of bulk Nb47wt%Ti when high cathode power is used. The data indicate a transition in the morphology of the film as power increases, which affects the rate at which interstitial atoms are incorporated into the growing film. After the target lost /spl sim/50% of its mass and acquired strong surface relief, bulk properties could not be obtained, because deposition rates for a given cathode power were lower than before. A small Ti enrichment (3-5%) between the films and the target was found for both sets of films.
Keywords :
Auger electron spectra; electrical resistivity; niobium alloys; scanning electron microscopy; sputter deposition; superconducting thin films; superconducting transition temperature; surface topography; titanium alloys; type II superconductors; Auger electron microscopy; Nb-Ti; SEM; Ti enrichment; bulk properties; cathode power dependence; critical temperature; film morphology; interstitial atoms incorporation; magnetron sputtering conditions dependence; resistivity; scanning electron microscopy; surface relief; target dependence; thin film; Cathodes; Conductivity; Electrons; Magnetic analysis; Magnetic multilayers; Niobium compounds; Sputtering; Temperature dependence; Titanium compounds; Transistors;
Journal_Title :
Applied Superconductivity, IEEE Transactions on