DETERMINATION OF MECHANICAL-PROPERTIES OF THIN-FILMS - A THEORETICAL FEASIBILITY STUDY

The aim of this work was to determine the principal mechanical paramet ers of a thin film on a substrate, i.e. Young's modulus, Poisson's rat io, intrinsic stress, and coefficient of linear thermal expansion. Fir st, standard experiments possibly suitable for this purpose were inves tigated theoretically. The margin of error of the mechanical parameter s determined was estimated as dependent on the geometrical conditions, substrate properties, and error in the respective measurements. In ad dition, the homogeneity and stability of the parameters were taken int o account, for instance inhomogeneity of the film thickness and possib le modification of substrate parameters during film growth. To obtain meaningful results, the accuracy of the measurements as well as the ho mogeneity and stability of several geometrical and physical parameters in general must be extremely high. However, the experimental conditio ns were found to fulfill these requirements.