SMOOTHING OF YBA2CU3O7-DELTA FILMS BY ION CLUSTER BEAM BOMBARDMENT

Smoothing high-temperature superconductor (HTS) surfaces, especially H TS thin-film surfaces, is crucial for HTS thin-film device processing. In this letter, we describe a method to planarize the surface of a YB a2Cu3O7-delta HTS film down to a smoothness with a standard deviation of 1 nm or better. The method includes first smoothing the HTS surface by ion cluster beam bombardment, followed by annealing in oxygen ambi ent to regrow the damaged surface layer. Additional YBCO layers can be grown epitaxially on the treated surface, even without removing the t op surface layer, which contained some residual damage after annealing . This method can be integrated into HTS circuit fabrication as a key step of planarization. (C) 1998 American Institute of Physics.