Effect of grain shape on the agglomeration of polycrystalline thin films

TL;DR

This paper investigates how the shape of grain interfaces, whether rounded or faceted, influences the stability and agglomeration of polycrystalline thin films through grain-boundary grooving effects.

Contribution

It introduces a comparison of agglomeration behaviors in thin films with different interface shapes, emphasizing the role of anisotropy and interface energy differences.

Findings

Shape dramatically affects agglomeration stability.

Small energy differences can destabilize or stabilize grains.

Anisotropy is central to interface stability.

Abstract

Grain-boundary grooving is a general phenomenon occurring in all polycrystalline materials at the intersection between the grain-boundary and the interface or free surface. It has been studied theoretically for some time. Grain-boundary grooving in the context of faceted interfaces in particular has attracted some attention. However, these works did not consider the case of thin films and the consequences on agglomeration of the shape of the interface. In this Letter, we compare the agglomeration of thin films with rounded and faceted interfaces. The shape of the grains can dramatically affect the agglomeration of polycrystalline thin films by grain-boundary grooving. Anisotropy plays a central role in the stability against agglomeration of faceted films. Even a small difference between the interface energies of the facets can destabilize faceted grains or, on the contrary, it can make them perfectly stable at any thickness. keywords: grain-boundary grooving, dihedral angle, faceting, energy, silicide, theory, model.