AVS 60th International Symposium and Exhibition
    Spectroscopic Ellipsometry Focus Topic Wednesday Sessions
       Session EL+AS+EM+SS+TF-WeA

Paper EL+AS+EM+SS+TF-WeA12
Anisoptropic Bruggeman Effective Medium Approaches for Slanted Columnar Thin Films

Wednesday, October 30, 2013, 5:40 pm, Room 101 A

Session: Spectroscopic Ellipsometry: Perspectives and Novel Applications
Presenter: D. Schmidt, University of Nebraska-Lincoln
Authors: D. Schmidt, University of Nebraska-Lincoln
E. Schubert, University of Nebraska-Lincoln
M. Schubert, University of Nebraska-Lincoln
Correspondent: Click to Email
Two different formalisms for the homogenization of composite materials containing ellipsoidal inclusions basedon Bruggeman’s original formula for spherical inclusions can be found in the literature [1,2]. Both approximations to determine the effective macroscopic permittivity of such an idealized composite assume randomly distributed dielectric particles of equal shape and differ only in the definition of the depolarization factors. The two approaches are applied to analyze ellipsometric Mueller matrix spectra acquired in the visible and nearinfrared spectral region from metal and semiconductor slanted columnar thin films. Furthermore, the effective dielectric function tensor generated by the two Bruggeman formalisms is compared to effective major axes dielectric functions individually determined with an assumption-free homogeneous biaxial layer approach.

Best-match model parameters of all three model approaches are discussed and compared to estimates fromscanning electron microscope images. It was found that all three optical model equivalents for slanted columnar thin films agree well with the imaging technique and that no preference can be given to any one of the two Bruggeman formalism in terms of structural properties determination.

Application of the effective medium approximation models will be highlighted on the example of in-situ monitoring of dielectric and metal conformal coating growth onto slanted columnar thin films by atomic layer deposition.

[1] D. Polder and J. H. van Santen, Physica 12, 257 (1946).

[2] Mackay and Lakhtakia, J. Nanophoton. 6, 069501 (2012).