Analysis of semiconductor surfaces with very thin native oxide layers by combined immersion and multiple angle of incidence ellipsometry

Abstract

In this paper the method of immersion and multiple angle of incidence ellipsometry is used for analyzing silicon and germanium single crystals covered with very thin native oxide layers under normal laboratory conditions. The method is applied at a wavelenght of 632.8 nm. If the values of the absorption index of both semiconductors are known with sufficient accuracy, the values of the refractive index of these semiconductor substrates, the refractive index and the thickness of the effective surface layers (a double layer consisting of the native oxide layer and the interface layer between the semiconductor and this native oxide film) can be determined with relatively high accuracy. These values are compared with those found by other researchers. The thickness and the refractive index of the native oxide layer on the silicon single crystal substrate are also evaluated taking into account the existence of the interface layer.