Texture Effects in Solid-State Reactions of Thin Films

Abstract

The texture of thin films, originating from a solid state reaction between a deposited film and a single crystal substrate is investigated. The relation between the phase formation and texture is analyzed for a number of these systems, such as Co/Si, Ni/Si or Co/Ge, where a metal film is allowed to react with a semiconductor single crystal substrate during heating and a summary of these results in presented in this article. It was found that the texture of the resulting films can be very complex, consisting of a variety of simultaneously occurring texture components such as epitaxy, fiber and axiotaxy texture. The close connection between the phase formation and texture is demonstrated by the fact that even a small intervention in either one, can have a huge effect on the resulting phase and/or its texture. From this, we show that the effect of the addition of ternary elements (e.g. Pt, W, C) to the thin films can only be understood if one considers its effects on both the kinetics and the thermodynamics of the reactions, as well as on the texture of the phases. We show how this can be used to influence technologically important properties of the films, such of formation temperature or stability.