Electron microscopy of multilayer thin films

Abstract A replica technique for obtaining electron micrographs of the cross-sectional structure of multilayer thin film systems is described in detail. The importance of such techniques is emphasised in the introductory section, and is attributed to the fact that they provide direct evidence of structural features whose existence has previously been inferred from measurements of the optical performance of the multilayer systems. Four micrographs are used to illustrate the usefulness of the technique, specifically in that they show structural features which could give rise to optical inhomogeneity and anisotropy in the layers as well as unevenness in the boundaries. It is also shown how measurement of the inter-boundary distances can provide information about the effectiveness of the optical thickness monitor used in the preparation of the multilayer system.