Dielectric functions of a growing silver film determined using dynamic in situ spectroscopic ellipsometry

Abstract

The dielectric functions of plasma deposited silver on SiO2 through all stages of Volmer-Weber growth at room temperature and 150 degrees C were determined unambiguously by applying a model-independent inversion method to dynamic in situ spectroscopic ellipsometric data. The results show large differences in the localized plasmon resonance and the percolation threshold at the two temperatures. Using these model-independent dielectric functions we assess the effectiveness of modelling the plasmon resonance by fitting a Lorentz oscillator. The methods show agreement for the position of the plasmon resonance below the percolation threshold and for the effective film thickness up to 5.6 nm at room temperature and 11.5 nm at 150 degrees C, however the line shape of the resonance is described by the Lorentzian only in the early stages of film growth.