DIRECT-CURRENT REACTIVE MAGNETRON-SPUTTERED ZINC-OXIDE THIN-FILMS - THE EFFECT OF THE SPUTTERING PRESSURE

ZnO thin films were deposited onto glass substrates by d.c. reactive m agnetron sputtering from a metallic zinc target. QI systematic study h as been made on the influence of sputtering pressure in the range from 0.2 Pa to 3 Pa on the film structural and optical properties. At low sputtering pressure (0.2-0.4 Pa), the film was inhomogeneous, non-stoi chiometric and had low refractive index and an almost amorphous struct ure. At high sputtering pressure (0.6-0.8 Pa), the film was homogeneou s, stoichiometric and had high refractive index and the crystallinity was improved. As the sputtering pressure was further increased (1-3 Pa ), the homogeneity and the refractive index of the film had no clear v ariation, but the crystallinity of the film went down. As the sputteri ng pressure was increased from 0.2 Pa to 3 Pa, the transmittance of th e film increased and the deposition rate of the film decreased.