Phase-field model for grain boundary grooving in multi-component thin films

TL;DR

This paper introduces a versatile phase-field model to simulate grain boundary grooving in multi-component thin films, capturing microstructural evolution and interface behaviors with analytical and numerical validation.

Contribution

It presents a comprehensive phase-field framework capable of modeling complex multi-component thin film microstructures and interface phenomena, including segregation effects.

Findings

Accurately reproduces theoretical groove angles at and far from equilibrium.

Validates analytical interface profiles with numerical simulations.

Demonstrates application to Ni(Pt)Si thin films on silicon.

Abstract

Polycrystalline thin films can be unstable with respect to island formation (agglomeration) through grooving where grain boundaries intersect the free surface and/or thin film-substrate interface. We develop a phase-field model to study the evolution of the phases, composition, microstructure and morphology of such thin films. The phase-field model is quite general, describing compounds and solid solution alloys with sufficient freedom to choose solubilities, grain boundary and interface energies, and heats of segregation to all interfaces. We present analytical results which describe the interface profiles, with and without segregation, and confirm them using numerical simulations. We demonstrate that the present model accurately reproduces the theoretical grain boundary groove angles both at and far from equilibrium. As an example, we apply the phase-field model to the special case of a Ni(Pt)Si (Ni/Pt silicide) thin film on an initially flat silicon substrate.