OPTICAL-PROPERTIES OF ALUMINA AND ZIRCONIA THIN-FILMS GROWN BY PULSED-LASER DEPOSITION

Sintered targets of ZrO2 and Al2O3 are ablated by KrF excimer laser ra diation. The processing gas atmosphere consists of O-2 at typical pres sures of 10(-3)-l mbar. Films with a thickness of 200-700 nm are depos ited on a Pt/Ti/Si multilayer substrate. The analytical techniques use d for the determination of structural characteristics of the films are X-ray diffraction and electron microscopy. The thickness and the comp lex refraction index are determined by ellipsometry by fitting a model for the film geometry to the measured data. The optical film thicknes s at different wavelengths is determined using interference reflection photometry. The investigations concentrate on the influence of the ox ygen pressure, the target-to-substrate distance and the laser fluence on the refraction index of the films, which is correlated with the fil m density. The compaction of the films is achieved by particles imping ing with kinetic energies above 30 eV on the growing surface. The kine tic energy of the particles depending on the processing parameters is modelled and related to the resulting film properties. (C) 1998 Elsevi er Science S.A.