Grain Growth Suppression and Enhancement by Interdiffusion in Thin Films

Abstract

ABSTRACTGrain structure and grain growth in thin metallic films are important because of their effects on properties such as yield strength, electrical resistance and electromigration resistance. Since almost all thin films are used in contact with a substrate and many also have contacts with overlayers, it is important to consider how interactions with other materials affect the grain growth process. In this paper we consider the effects of diffusive interactions. We will show that interdiffusion often accompanies grain growth and that it can result in a number of novel grain boundary reactions, driven by a variety of effects. Using TEM techniques, we demonstrate cases of grain growth suppression and grain growth enhancement resulting from interdiffusion of solute atoms in gold thin films. The reasons for the observed effects will be considered with a view to providing a fundamental understanding of the types of systems that might be expected to exhibit the various phenomena.