Chemical Etching of High-Tc Superconducting Films in Feliox-115 Solution

A new chemical etching technique of high-T c superconducting Y-Ba-Cu-O and Er-Ba-Cu-O films has been developed by employing a novel etchant Feliox-115. It offered a diffusion-limited etching. The rate (at 20°C) and the activation energy of Y-Ba-Cu-O dissolution were, respectively, 0.5 µm/min and 0.32 eV. The Er compound was etched off more preferentially than the Y one: The etching rate of the former was nearly twice as high as the latter. The degradation of T c induced during this process was at most 4 K.