Ellipsometric studies of nanocrystalline silicon films with the thicknesses less than 100 nm

Abstract

Our study deals with the structure of thin nanosilicon films having the thicknesses less than 100 nm. It is measured using multi-angular and spectral ellipsometry methods. Modelling of angular dependences of the ellipsometric parameters shows a significant dependence of both structure and composition of the nanosilicon films upon their thickness. In particular, the volume fraction of voids increases with decreasing thickness of the film. The effect of SiO x shell of the nanocrystals on the optical properties of our films can be neglected. When the thickness of the nanocrystalline layer is less than 50 nm, the compositions of this layer and the surface-roughness layer become practically identical.