Electrical contact studies of chemically treated YBa2Cu3O7-x surfaces

Results on electrical characterization of high Tc thin film surfaces modified by different surface treatments are presented. In particular, this work examines the effect of a Br/ethanol chemical etch, which has previously been shown to remove surface contamination while preserving the Cu(+2) oxidation state. Electrical measurements of YBa2Cu3O7-x/Au/Nb contact structures fabricated using polycrystalline, post-annealed YBa2Cu3O7-x films with Br-etched surfaces, show improvements of approximately one to two orders of magnitude in contact current densities and resistivities (resistance-area products) relative to unetched contacts. The Br-etch process has produced 10x10 μm2 contacts with contact current densities greater than 400 A/cm2 and RnA products as low as 4x10-7 Ω-cm2