INDENTATION OF STRAINED SILICATE-GLASS FILMS ON ALUMINA SUBSTRATES

Abstract

The understanding of mechanical properties of thin films on substrates requires an understanding of the stresses in the film structures and a knowledge of mechanisms by which thin films deform. These stresses may compromise the performance of integrated circuits, magnetic media, etc. Similarly, in structural multiphase ceramics, the presence of residual and thermal stresses between the matrix and intergranular films is a common source of failure causing deformation and fracture. A variety of techniques and methods have been developed to study the effect of processing and testing conditions on the mechanical behavior of thin films. The technique introduced in the present paper offers a new method of studying residual stresses in thin films. It combines the approaches developed for a bimaterial bending test frequently used to measure interfacial fracture energies in a purely brittle ceramic system with the new developments in nanoindentation techniques. Emphasis is given to the stress-related effects that occur in brittle films on brittle substrates such as silicate-glass films on single-crystal alumina; changes are observed in both the surface morphologies and the indentation data.