Ion-beam sputter deposition process for Y1Ba2Cu3O7-δ thin-film structures

Abstract

Ion-beam sputter deposition (IBS) has been developed to a fully oxygen-compatible technology for growth of complex oxides, such as Y1Ba2Cu3O7−δ (YBCO) thin films. The IBS system consists of an rf-plasma ion source with molybdenum grids for sputtering, a dc-plasma electron source for space charge compensation, stoichiometric YBCO and NGO targets, a beam chopper with BaO2, Cu, and Nd blades for stoichiometry control, and an ECR-oxygen-plasma source for in situ film oxidation and photoresist removal. Due to its complexity the IBS process is fully computer-controlled. A salient feature of IBS is the excellent crystallographic and morphological properties of thin (100)/(010)- and (103)-oriented YBCO films on SrTiO3 (STO) and NdGaO3 (NGO) substrates. Sharp interfaces and good superconducting properties render this technology feasible for the fabrication of SIS-ramp-junction SQUID's.