High resolution patterning of high Tc superconductors

A novel method for submicron patterning of high Tc superconductor thin films is presented. Specifically, we describe the patterning of the superconductor YBa2Cu3O7−x (YBCO) on single crystal SrTiO3 wafers by a selective epitaxy approach. A silicon nitride template is formed on the SrTiO3 using electron beam lithography and reactive ion etching. A thin film of YBCO is then deposited on the wafer, e.g., by laser ablation. Selective epitaxy occurs during the deposition process, the YBCO film grows epitaxially on SrTiO3, while the film depositing on the nitride forms insulating clusters. Good epitaxial films and patterns have been obtained as‐deposited without the need for further annealing or other process steps. Lines as narrow as 130 nm have been fabricated which show no significant decrease in Tc as compared with the original blanket film.