Etching and annealing of substrates for superconducting multilayers and devices

摘要

The structural and electrical quality of YBa/sub 2/Cu/sub 3/O/sub 7- delta / grown on ion-etched substrates by a variety of techniques was investigated. Co-evaporated YBa/sub 2/Cu/sub 3/O/sub 7- delta / films deposited and postannealed on etched LaAlO/sub 3/ substrates have substantially higher room-temperature resistivities and wider c-axis rocking curve widths than films on unetched substrates. Annealing of the etched substrate prior to evaporation narrows the c-axis rocking curve width and restores resistivity and critical current densities to values comparable to those of the unetched controls. Laser-ablated films on etched substrates show a smaller absolute magnitude of rocking curve broadening and no change in DC electrical properties. An increase of the inhomogeneous strain was also observed in coevaporated postannealed and laser-ablated films on etched substrates.