Surface etching of YBCO films by xenon difluoride

Benjamin L. Crossley
Alfredo A. Corrales
Everett E. Crisman, University of Rhode Island

Abstract

We have demonstrated that xenon difluoride (XeF2) etches thin films of YBa₂Cu₃O_7−x, the superconducting form of yttrium–barium–copper–oxide (YBCO), during dry etch processing. Both c-axis and mixed a/c-axis YBCO films show evidence of such etching with a axis being more reactive. Profiles of YBCO films examined by ESCA show that the surfaces of both etched and unetched films are barium rich at the expense of yttrium. After XeF₂ etching, fluorine was found to be present to a depth of at least 40 nm. Despite the etching and the presence of fluorine in the YBCO films, the superconducting transition temperature, T_c, was unaffected by the XeF₂ treatment.