Strained substrates, composition inhomogeneities, grain shape and the agglomeration of germanosilicide thin films

TL;DR

This paper investigates how substrate strain, composition inhomogeneity, and grain shape influence the stability and agglomeration of germanosilicide thin films, revealing that strain and grain shape significantly affect film behavior.

Contribution

It introduces a thermodynamics model showing that strained substrates lead to inhomogeneous germanium composition and increased agglomeration in germanosilicide films, supported by experimental agreement.

Findings

Inhomogeneous Ge composition increases on strained substrates.

Polygonal grains are more prone to agglomeration than rounded grains.

Strain enhances the likelihood of film agglomeration.

Abstract

Germanosilicide thin films are quite different from silicides and germanides. The germanium composition is not homogeneous, grains have a different shape, and the substrate is generally strained. This affects grain boundary grooving and favors agglomeration of germanosilicide films. Our thermodynamics model shows that the equilibrium Ge composition of germanosilicide films formed on strained substrates is inhomogeneous and these films are more likely to agglomerate than those formed on relaxed substrates, in agreement with experiments. Grain shape too can affect agglomeration: polygonal films, such as germanosilicides, are more likely to agglomerate than films with rounded grains (silicides, germanides).