Fabrication and I-V Characteristics of High-T_c Nb₃Ge Microbridges

Abstract

High- T c Nb 3 Ge microbridges are fabricated by electron-beam lithography combined with CF 4 reactive sputter etching. The bridges are 0.48 µm wide and 0.36–0.6 µm long. The temperature dependence of I c is found to be proportional to (1- t ) 5/2 at t >0.8 ( t = T / T c ). This result means that the bridge region behaves like an inhomogeneous type-II superconductor film. 9.75 GHz microwave induced steps are observed throughout a wide temperature range. The steps are observed above 20 K in some bridges.