Highly-oriented ZnO films by rf sputtering of hemispherical electrode system

Abstract
Highly oriented ZnO films (c‐axis orientation) were fabricated on glass and fused‐quartz substrates by an rf‐sputtering system with a hemispherical electrode configuration. The sputtered films show a high longitudinal mode electromechanical coupling factor, kt=0.23–0.24. Initial results suggest that the hemispherical electrode configuration may provide improved reproducibility over planar sputtering systems in the preparation of ZnO films for acoustic device applications.