Atomistic insights into workpiece width effects in single-crystal silicon nanoindentation process

The application of single-crystal silicon in ultra-large-scale integrated circuits, micro-electromechanical systems, and various optoelectronic devices is widely used. However, the mechanical behavior and internal amorphous structure evolution mechanisms of single-crystal silicon at the nanoscale remain incompletely understood. This study employs molecular dynamics simulations to investigate how workpiece width influences internal amorphous structures and stress distribution during nanoindentation. Atomistic simulations reveal that reduced workpiece width significantly exacerbates edge collapse at the indentation site, manifested by pronounced atomic displacement and surface sinking. Moreover, atomistic visualization demonstrates that the spatial distribution of internal amorphous structures exhibits marked heterogeneity across different cross-sections, dictated by the interplay of workpiece width and indentation depth. Atomic-level stress analysis shows that workpiece width and indentation depth synergistically govern the spatial extent and configuration of high-stress domains. These concentrated stress fields directly drive localized atomic amorphization and plastic deformation. This investigation offers fundamental atomistic perspectives on the mechanical response mechanisms of single-crystal silicon during nanoindentation and offers guidance for optimizing nanomachining processes and reliability of micro/nano devices.