Effect of temperature on surface morphology of single-crystal silicon in nanometric cutting

Abstract

Laser-assisted machining (LAM) is an attractive strategy to improve the machinability of single-crystal silicon. During LAM, understanding the effect of machining temperature on surface formation is important for improving the machined surface quality. This study aims to an in-depth comprehension in the surface formation mechanism during nanometric cutting of single-crystal silicon under different temperature conditions by molecular dynamics (MD) simulation. A two-cut model was established to simulate the nanometric cutting process and annealing simulation was conducted on the machined workpiece at a range of temperatures. The results revealed that the asymmetrical material load induced by former machined groove could promote deflection of the material flow, which is more obvious at high cutting temperatures. In the subsurface workpiece, an asymmetrical amorphous layer is formed with dislocations interacting with former defects. When the cutting temperature increases, recrystallization of the disordered phases into cubic and hexagonal structures is activated. By the annealing process, the pile up generated from cutting can be eliminated with less amorphous atoms and dislocations remains in workpiece. These results could help to improve the understanding of the thermal effect on surface formation mechanism and provide insights into the thermal repairing of the machining-induced defects on single-crystal silicon.