Determining optical constants using an infrared ellipsometer.

ABSTRACT

In the infrared region high refractive index coating materials, such as PbTe and Ge, are normally semiconductors. Their optical constants n, k, and d are strongly dependent on the deposition process. For the most practical coating designs, the layers are usually not very thick, of the order of a half or quarter wavelength, and are weakly absorbing. To determine the optical constants of such thin films using an infrared ellipsometer, some problems exist which must be solved (1) the precision of n, k, and d and (2) multiple solutions. In this paper these problems are solved by theoretical analysis and experimental arrangement. Experimental results are given and an experimental measurement method is presented.