Quasi-discrete modeling of step-flow dynamics: capturing bunching and debunching in sic solution growth
Journal
Journal of Crystal Growth
Journal Volume
675
Start Page
128420
ISSN
00220248
Date Issued
2026-01-30
Author(s)
Abstract
Step-flow dynamics during SiC solution growth critically shape surface morphology and defect formation, yet conventional models often average step densities or encounter front-tracking singularities, missing transient bunching and debunching. We introduce a quasi-discrete 2D/3D model that couples advection–diffusion transport with Gaussian-regularized Robin boundary conditions, representing macrosteps as localized, integral-matched sinks. Each macrostep is resolved by a few Gaussian-weighted nodes while solute transport is computed on a fine finite-element mesh, ensuring stability and mass conservation. Simulations reveal that parallel flow drives strong bunching, producing wide terraces with amplified supersaturation; bunched steps advance more slowly due to solute depletion, while high-supersaturation pockets accelerate leading steps and trigger debunching. Conversely, anti-parallel flow advects depletion upstream and preserves uniform step spacing, with no bunching across tested conditions. In three dimensions, parallel flow yields stripe coalescence, while anti-parallel flow stabilizes step trains. By quantifying terrace supersaturation's link to polytype nucleation, this robust, efficient model offers a predictive tool for optimizing step morphology and minimizing defects in high-quality SiC crystal growth.
Subjects
Debunching
Gaussian Robin BC
Polytype nucleation
SiC
Solution growth
Step bunching
Terrace supersaturation
Publisher
Elsevier B.V.
Type
journal article