Determination of optical constants of thin film from reflectance spectra.

We present a method of determining optical constants n and k of a thin film using only the reflectance R(omega) curve (normal incidence reflectance spectroscopy). The method is based on the simultaneous use of Fresnel laws and dispersion relations between n and k of the film, via an iterative process. To illustrate the method, optical constants in the VUV of a film grown on InP were determined. A second example with a SnO(2) film shows how the method can reduce the effect of experimental errors when two sets of spectroscopic data are available.