Dielectric behavior of triethoxyfluorosilane aerogels

Low dielectric constant aerogels are being considered by the semiconductor industry as interlayer dielectrics to overcome capacitance problems which limit device feature sizes. Using sol-gel methods and CO₂ supercritical drying, a triethoxyfluorosilane (TEFS) precursor has been used to prepare bulk aerogels. Effects of pH and water to precursor ratio were studied with respect to aerogel dielectric and chemical properties. Methods of analysis for this study include FTIR-ATR and dielectric constant determination by impedance. Si-F bonds were determined to be present in both acid- and base-catalyzed TEFS. Dielectric constants were determined to increase slightly with increasing water to precursor ratios.