A simple technique for obtaining (1120) or (1010) textured ZnO films by RF bias sputtering

C-axis parallel-oriented ZnO piezoelectric films, (112̅0) or (1010) textured films, are good candidates for shear mode devices. Ion bombardment to the substrate during film deposition suppresses the usual (0001)-oriented grain growth, resulting in the preferential development of unusual (1120) or (1010) orientation. This is because the most densely packed (0001) plane should incur more damage by ion bombardment than the (1120) and (1010) planes. In this study, we propose RF substrate bias RF magnetron sputtering method to induce the ion bombardment to the substrate. This method made possible to form preferential (1120) or (1010) orientation in the conditions where these orientations could not be formed in case of DC bias.