Characterization of zirconia films deposited by rf magnetron sputtering

Thin films of zirconium oxide were prepared by r.f. magnetron sputtering fr om a ZrO2 target. A systematic study has been made on the influence of the sputtering parameters (total pressure, oxygen partial pressure and r.f. pow er) on the film composition and on their structural and optical properties. The zirconia films crystallize either in the cubic or in the monoclinic ph ases depending on the sputtering gas. The crystallinity and the compactness of the films were found to increase with the kinetic energy of the sputter ed particles. The stresses are compressive and become very important in thi ck films deposited at a high power density. Films are generally substoichio metric and their O/Zr atomic ratio was found to increase with the oxygen pa rtial pressure. On the contrary, films deposited at high sputtering pressur es (more than 5 Pa) contain an oxygen excess. This overstoichiometry result s, as it was revealed by F. T. I. R. analyses, from the incorporation of wa ter and hydroxyl groups into the ZrO2 structure. The optical constants (ref ractive index and extinction coefficient) vary also in a wide range with th e deposition conditions. These variations were correlated mainly to structu ral properties. (C) 1998 Elsevier Science S.A. All rights reserved.