Dry Etching of Nb and Fabrication of Nb Variable-Thickness-Bridges
Takeshi Harada, Kenji Gamo, Susumu Namba
Several reactive dry etching methods; ion etching, sputter etching and plasma etching, were studied in order to fabricate a niobium variable-thickness type thin film bridge (VTB). Niobium was etched by CF4 reactive sputter etching with submicron accuracy and no significant influence on the superconducting transition temperature except very near the surface (<200 Å). The niobium VTB behaved as an S-S'-S bridge, and a reduced self-heating effect was realized by a variable-thickness geometry. The DC Josephson effect was observed in the temperature range without thermal hysteresis. The quality factor of the I c R n product obtained was at least 0.42 mV.
Japanese Journal of Applied Physics•Jan 1, 1981•27 citations