STUDY OF THE INFLUENCE OF OXYGEN ON THE COMPOSITION OF THIN-FILMS OBTAINED BY RF-SPUTTERING FROM A CA-5(PO4)(3)OH TARGET

In this paper we present a study of the influence of the presence of o xygen during sputter deposition on the properties of the films obtaine d from a Ca-5(PO4)(3)OH (HA) target. The films were characterised usin g X-ray diffraction, Fourier transform infrared spectroscopy and profi lometer measurements. The composition of the deposited films was obtai ned by Rutherford backscattering spectrometry measurements. We found t hat an increase of the oxygen pressure resulted in a strong reduction of the growth rate of the films. Also a better stoichiometry of the fi lms with respect to HA was obtained by intentional introduction of oxy gen in the sputtering gas. Furthermore, we have shown that the average Ca/P ratio increases to a higher value than the Ca/P ratio of the tar get, with increasing film thickness and with increasing external negat ive bias on the substrate. (C) 1997 Elsevier Science S.A.