Reactive ion etching of niobium

Abstract

The reactive gases CBrF3 and CF4 have both been found to be effective in the reactive ion etching of niobium. At relatively high pressures, 100 mTorr, rapid etching with a small degree of undercutting occurs at moderate rf power levels. At lower pressures, higher rf power levels, ≳1 W/ cm2, are required but vertical edge profiles result. The RIE process can be useful in producing electrodes for Josephson circuits and superconducting microbridges.