Focused ion beam processes for high-<i>T</i> <i>c</i> superconductors

Abstract

Focused ion beam (FIB) processes have been developed for Y–Ba–Cu–O superconductor films. A Y–Cu liquid metal ion source has been fabricated, using a Y67 –Cu33 eutectic alloy as the ion source. As-sputtered Y–Ba–Cu–O film etch rate ratios to GaAs(100) and Si(100) substrates are 0.28 and 1.4 for 130-keV Au+ FIB ion etching, respectively. Y–Ba–Cu–O submicron patterns have been demonstrated by using FIB lithography and Cl2 reactive ion beam etching. Moreover, a Y–Ba–Cu–O superconducting line with 4-μm linewidth has been fabricated by annealing an as-sputtered Y–Ba–Cu–O line pattern. Tc control of Y–Ba–Cu–O film has been achieved by 200-keV Ne+, using conventional ion implantation and 300 keV Si++ FIB ion implantation.