We prepared Bi2Sr2Can-1CunOy (BSCCO) thin films by RF magnetron sputtering using a mixture of He + O2 sputtering gas (He : O2= 4 : 1). As helium gas effectively generates active particles of O2+ and O+ by the Penning ionization effect, the crystallinity of the films is expected to improve.
The crystallinity and the composition of films were dependent on the composition of targets. When we prepared the Bi -2212 films using the targets of Bi : Sr : Ca : Cu = 2 : 2 : 1 : Z (Z = 1.0-3.0), the best crystallinity of the film was obtained using the target of Z = 2.0. Furthermore, we prepared the Bi-2223 films with the composition of target, Bi : Sr : Ca : Cu = 2 : 2 : 2 : 3. The films with dominant Bi-2223 single phase were obtained only at Tsub = 630°C, but Bi-2223 and Bi-2212 mixed phases appeared at the other substrate temperatures.