Spectroscopic ellipsometry approximation

In addition to measurement of the dielectric constant at frequencies ranging from 10 kHz to 1 MHz through capacitance measurement using evaporated dot contacts, it is possible to use spectroscopic ellipsometry to evaluate its refractive index. The complex refractive index is the square root of the product of the complex relative dielectric constant and the complex relative permeability. Since ULK films are nonmagnetic, the permeabUity can be approximated by unity. While it is true that the eUipsometry... 

The optical properties and thickness of the films were quantified using spectroscopic ellipsometry (M-2000, J.A. Woollam). Film porosity was calculated from the Bruggemann effective medium approximation (BEMA) model [11,54], assuming that only two phases existed amorphous silica and voids. The refractive index of the film was determined and directly translated into the film porosity, knowing the refractive index of the wall framework. The wall was assumed to be solely amorphous silica with a reported refractive index of 1.458. The film porosity calculated was found to be in the range of 50-60%. 

Aspnes, Theeten, and Hottier made spectroscopic ellipsometry measurements of a surface with induced roughness, and examined calculations with various approximations based on the effective medium model represented by the following relation for the effective dielectric constant < > for a composite layer composed of materials 1 and 2 dispersed in a host medium ... 

Schmidt et al. [136] also reported room-temperature spectroscopic ellipsometry results on pulsed laser deposition-grown wurtzite MgxZni xO (0thin films. The refractive index data were fit to a three-term Cauchy approximation type formula (Equation 3.105), and the anisotropic Cauchy model parameters A, B, and C for ZnO were obtained as 1.916,1.76, and 3.9 for E J c and 1.844,1.81, and 3.6 for... 

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