Dresden 2003 – scientific programme

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DS: Dünne Schichten

DS 23: Elektrische und optische Eigenschaften II

DS 23.10: Talk

Thursday, March 27, 2003, 17:30–17:45, GER/38

Contributions to the dielectric constant of low-k silica xerogels films — •C Himcinschi¹, M. Friedrich¹, S. Fruehauf², S.E. Schulz², T. Gessner², and D.R.T. Zahn¹ — ¹Institut für Physik, Technische Universität Chemnitz, — ²Zentrum für Mikrotechnologien, Technische Universität Chemnitz

Low-k silica xerogel films produced using different aging / hydrophobisation conditions were used to investigate the various contributions to the static dielectric constant determined from C-V characteristics. The static dielectric constant є₀ was in the range 2-2.6 and consists of electronic Δ є_e , ionic Δ є_i and configurational Δ є_c contributions: є₀=Δ є_e+Δ є_i+Δ є_c where 1 is the dielectric constant of vacuum. The electronic contribution to the dielectric constant was estimated in visible range from the refractive index determined by Variable Angle Spectroscopic Ellipsometry (VASE) measurements. The dielectric constant in the IR range є_IR consists of vacuum, electronic and ionic contributions. є_IR was calculated from IR transmission spectra describing the film as a Lorentz layer with several absorption peaks. For the films under study with porosities in the range 40-55%, the main difference between static dielectric constants was found to arise from the configurational contribution.