TECHNIQUE FOR CHARACTERIZATION OF THIN-FILM POROSITY

Properties of thin films change with, and as a result of, porosity. It is important to know and understand these effects; however, it is dif ficult to measure them. In this work, several films with differing amo unts of porosity were deposited by sol-gel methods onto quartz substra tes and analyzed using a combined SAW/BET technique and ellipsometry. Gas adsorption was measured by a surface acoustic wave (SAW) device, a nd porosity was calculated using BET equations. Porosity data was comp ared and correlated with measurements made by ellipsometry (film refra ctive index and thickness) and SEM (surface topography). As these tech niques do not yield pore size distribution, they are complimentary to the SAW technique, which directly measures porosity information. (C) 1 998 Elsevier Science S.A. All rights reserved.