Effect of nano-scratch speed on removal behavior of single crystal silicon

As a typical hard and brittle material, single-crystal silicon exhibits different strain rates at varying scratching speeds, leading to diverse material removal behaviors. Molecular dynamics was used to study the deformation and removal processes of single-crystal silicon at different scratching speeds from the perspective of strain rate. The results show that the strain rate of the material increases from 1.25 × 10¹⁰ s⁻¹ to 1.25 × 10¹¹ s⁻¹ as the scratching speed increases from 25 m/s to 250 m/s. At the same time, the scratching parameters, including scratching force, shear stress, and friction coefficient, decrease while the scratching temperature increases. Additionally, the contour accuracy and roughness of the scratch surface improve with increased scratching speeds. Amorphization and phase transformation during the scratching process are the main mechanisms of nanoscale deformation in single-crystal silicon. The depth of the subsurface damage layer decreases from 2.24 nm to 1.89 nm with the increase of shear stress, while the depth of the amorphous layer increases with the rise in scratching temperature.