Technique for characterization of thin film porosity

• Published in: Thin solid films Vol. 332; no. 1-2; pp. 257 - 261
• Main Authors: TAYLOR, D. J, FLEIG, P. F, HIETALA, S. L
• Format: Conference Proceeding Journal Article
• Language: English
• Published: Lausanne Elsevier Science 02-11-1998
• Subjects: Condensed matter: structure, mechanical and thermal properties; Exact sciences and technology; Other nonelectronic physical properties; Physical properties of thin films, nonelectronic; Physics; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Characterization; Thin films; BET method; Acoustic surface waves; SEM; Porosity; Surface topography; Experimental study; Sol-gel process; Ellipsometry
• ISSN: 0040-6090; 1879-2731
• DOI: 10.1016/S0040-6090(98)01264-4

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.