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 difficult to measure them. In this work, several films with differing amounts of porosity were deposited by sol-gel methods onto quartz substrates and analyzed using a combined SAW/BET technique and ellipsometry. Gas adsorption was measured by a surface acoustic wave (SAW) device, and porosity was calculated using BET equations. Porosity data was compared and correlated with measurements made by ellipsometry (film refractive index and thickness) and SEM (surface topography). As these techniques do not yield pore size distribution, they are complimentary to the SAW technique, which directly measures porosity information. (C) 1998 Elsevier Science S.A. All rights reserved.