Shuhao Kang

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.

The edge effect refers to what occurs when an object undergoes elastic contact with the edge of a material. This is common in practical applications, but the understanding of this phenomenon is not yet mature enough, and understanding the microscopic characteristics of the material regarding this phenomenon is necessary. This article investigates the edge effects of single-crystal silicon at different indentation positions through molecular dynamics simulations. The results indicate that the edge effect of the indentation is influenced by the indentation position and depth. The closer the indentation head is to the edge of the workpiece, the more particles are extruded from the side of the workpiece and the wider the collapse range of the indentation surface. At the same time, the indentation position also affects the distribution of the von Mises stress and phase transition area. When the edge effect occurs, the von Mises stress and phase transition region tend to be concentrated near the workpiece edge. This study demonstrates the atomic-scale deformation mechanism of single-crystal silicon under varying indentation positions.