Growth of YBaCuO Superconducting Thin Films by Hollow Cathode Magnetron Sputtering

Abstract

Growth of High Tc Superconductor thin films is receiving considerable attention in the last three years. Various thin film deposition techniques are being tried to improve the reproducibility of the composition, texture and superconducting parameters like Tc and Jc. The deposition techniques can be classified into two heads — single source and multi source methods. Among the single source methods, magnetron sputtering and laser ablation techniques have been successful.

The main problem in magnetron sputtering using the conventional parallel plate geometry has been identified as the reverse sputtering of the film by the negative ions. This results in compositional changes. A hollow or cylindrical cathode helps reduce this problem.

We have deposited YBaCuO thin films from a stoichiometric cylindrical hollow target by DC magnetron sputtering. The hollow-cathode geometry was designed so as to eliminate the preferential resputtering of the film by the negative ions. The effect of partial pressure of Argon and oxygen on the stoichiometry of the deposited film has been studied. The ratio of argon to oxygen have been optimized so as to obtain uniform stoichiometry film over a large area.