Atomistic insights into ultrafast SiGe nanoprocessing

TL;DR

This paper introduces a multiscale computational framework for simulating ultrafast laser annealing of SiGe alloys at the atomic level, enabling precise control of nanoprocessing with validated experimental and simulation comparisons.

Contribution

It develops a novel multiscale atomistic-continuum simulation method that captures out-of-equilibrium kinetics during laser annealing, surpassing existing continuum-only models.

Findings

Validated the simulation framework against experiments and phase-field models.

Revealed complex changes in composition and morphology during laser annealing.

Demonstrated the method's applicability to strained, defected, and nanostructured SiGe.

Abstract

Controlling ultrafast material transformations with atomic precision is essential for future nanotechnology. Pulsed laser annealing (LA), inducing extremely rapid and localized phase transitions, is a powerful way to achieve this, but it requires careful optimization together with the appropriate system design. We present a multiscale LA computational framework able to simulate atom-by-atom the highly out-of-equilibrium kinetics of a material as it interacts with the laser, including effects of structural disorder. By seamlessly coupling a macroscale continuum solver to a nanoscale super-lattice Kinetic Monte Carlo code, this method overcomes the limits of state-of-the-art continuum-based tools. We exploit it to investigate nontrivial changes in composition, morphology and quality of laser-annealed SiGe alloys. Validations against experiments and phase-field simulations, as well as advanced applications to strained, defected, nanostructured and confined SiGe are presented, highlighting the importance of a multiscale atomistic-continuum approach. Current applicability and potential generalization routes are finally discussed.