Interplay between grain boundary grooving, stress, and dealloying in the agglomeration of NiSi1-xGex films

TL;DR

This study investigates how grain boundary grooving, stress, and dealloying influence the agglomeration of NiSi1-xGex films on strained substrates, revealing unique behaviors compared to other silicides.

Contribution

It uncovers the distinct properties of nickel germanosilicide, including grain morphology, groove sharpness, and dealloying, and links germanium out-diffusion-induced stress to agglomeration.

Findings

Germanosilicides have smaller, faceted grains.

Groove angles are sharper in germanosilicides.

Dealloying and germanium out-diffusion induce stress that promotes agglomeration.

Abstract

Germanosilicides, especially those formed on compressive substrates, are less stable than silicides against agglomeration. By studying the solid-state reaction of Ni thin film on strained Si0.8Ge0.2(001), we show that nickel germanosilicide is different from nickel silicide and nickel germanide in several respects: the grains are smaller and faceted, the groove angle is sharper, and dealloying takes place. The germanium out-diffusion creates a stress in the film which favors grooving and agglomeration.