Abstract

The determination of refractive index profiles in transparent layers, like every inverse problem remains a difficult task. The chance to get a realistic solution depends of course on the magnitude and shape of the profile and on the distance over which it is spread out. Two classes of problems can be identified: non intentional gradient resulting for example from the microstructure of the evaporated films (columnar growth in dielectric films) DI, or the adsorption of a polymer solution onto a solid wall[2], and intentional gradients designed for specific applications. In the second case, the profile deduced from optical measurements can be compared with the target after taking into account the errors introduced during the deposition process. The results that we present in this paper concern compositional gradients in silicon oxynitride films.

© 1995 Optical Society of America