Spectroscopic ellipsometry: A new tool for nondestructive depth profiling and characterization of interfaces

Abstract

The ability of spectroscopic ellipsometry to analyze the multilayer surface structure of an implanted semiconductor with 1–2 Å resolution has been demonstrated. Spectroscopic ellipsometric data from 1.5 to 4.5 eV on a number of self-ion-implanted silicon samples have been analyzed using the regression analysis technique. It is shown that such a procedure can yield information nondestructively and in a nonperturbing manner: (i) on the depth profile of multilayer structures; (ii) quantitative information on the thicknesses of each layer (within 90% confidence limits); (iii) the structure (whether crystalline or amorphous) as well as the degree of crystallinity in the region; (iv) characterize the oxide layer if present on specimen; and (v) microroughness of the surface, if present. Furthermore, it is shown that these results are in excellent quantitative agreement with the completely independent results obtained on the same specimens using cross-section transmission electron microscopy.