Solid-State Dewetting of Polycrystalline Thin Films: a Phase Field Approach

TL;DR

This paper develops a phase field model to simulate and analyze the complex dewetting behavior of polycrystalline thin films, revealing new insights into the role of grain boundaries and triple junctions in the process.

Contribution

It introduces a grandpotential multi-phase-field model for 3D polycrystalline film dewetting, including analytical criteria for the onset and detailed morphological evolution.

Findings

Model reproduces key dewetting phenomena in polycrystalline films.

Identifies critical role of triple junctions in dewetting.

Provides analytical benchmarks for dewetting onset.

Abstract

Solid-state dewetting is the process by which thin solid films break up and retract on a substrate, forming nanostructures. While dewetting of single-crystalline films is understood as a surface-energy-driven process mediated by surface diffusion, polycrystalline films exhibit additional complexity due to the presence of grain boundaries. Most theoretical and computational studies have focused on single-crystalline dewetting. Here, we present the application of the grandpotential multi-phase-field model to the dewetting of thin polycrystalline films in three dimensions, reproducing the key phenomenology of this process. By considering isotropic interface/surface energy, we illustrate its consistency with predictions based on energetic arguments and the morphological evolution towards equilibrium. We also provide novel analytical criteria for the onset of three-dimensional dewetting, serving as fundamental theoretical benchmarks, and highlight the critical role of triple junctions. Moreover, we unveil the dewetting behavior of polycrystalline patches, extending the scenarios of their single-crystalline counterparts.