Preparation of High Quality Bi₂Sr₂CaCu₂O_y Films by rf Magnetron Sputtering with Multi-targets

Abstract

We prepared Bi₂Sr₂CaCu₂O_y (Bi-2212) films by rf magnetron sputtering with the method with controlled shutters, and using an off-axis geometry, where a mixture of He with oxygen (He : O₂ = 4 : 1) was used as a sputtering gas. In this method, we used the two compound targets, Bi : Sr : Cu = 2.07.0 : 1.52.0 : 0.30.5 and Ca : Cu= 1.02.0 : 1.0. From the results, the method with controlled shutters was available to adjust the composition ratio on the substrate. And, we found that main phase of the films were a Bi-2201 although the composition of the films was approximately equal to that of an ideal Bi-2212. Thus, according to find out the optimum condition of Bi-2212 we found that there was possibility to fabricate the high quality films. This study underlines the high accuracy sputtering controlled shutter.