Coupled SPH-FEM modeling of Berkovich indenter scratching of single-crystal silicon

Single-crystal silicon, a key material in microelectronics, optoelectronics, and biomedical engineering, often incurs surface damage during diamond wire saw slicing, subsequently affecting surface quality and escalating costs. This study proposes a coupled SPH-FEM model for investigating the silicon scratching process, with an analysis of material removal and subsurface damage characteristics. The study investigates the scratching process with increasing normal loads and analyzes the influences of the normal load and the scratching direction on subsurface damage and stress. The results demonstrate a change from ductile-to-brittle transition (DBT) behavior in the workpiece as normal loads increase. The DBT critical loads are 29.2 mN and 21.6 mN for single-crystal silicon in the scratching directions of edge forward ( α  = 0°) and α  = 60°, respectively. The subsurface cracks and forces are substantially influenced by the normal load and the scratching direction. Scratching in the direction of α  = 60° results in a larger damage layer, more radial cracks, and deeper median cracks. Meanwhile, applying smaller normal loads can reduce the subsurface damage, decreasing the area and amplitude of the residual stress zone. This study presents findings for managing subsurface damage and residual stress during the scratching process of hard and brittle materials.