Molecular dynamics simulation of nano-polishing of single crystal silicon on non-continuous surface

Abstract A molecular dynamic model of diamond abrasive polishing single crystal silicon is established. The effects of pores on the material removal process and the mechanism of pore wall material removal are studied from the aspects of displacement, polishing force, and phase transformation. The simulation results show that the removal method of material at pore walls is mainly shear and extrusion. The deformation of the pore walls in the entry areas of pores is an elastoplastic mixed deformation, and the deformation of the pore walls in the exit areas of pores is plastic deformation. Increasing the polishing depth increases plastic removal of material at pores. The existence of pores makes the tangential and normal forces decrease to a certain extent during the entire polishing process. The fluctuation of the normal polishing force is greater than that of the tangential polishing force. The lack of material at the pores is the main reason for the decrease of the normal polishing force. As the polishing depth increases, the tangential force increases significantly, and the normal force increases less. During the polishing process, phase transformation atoms with coordination number of 5 and phase transformation atoms with coordination number of 6 are main types of phase transformation atoms. High-pressure phase transformation is the main form of phase transformation. Due to the lack of atoms at the pores, the phase transformation of the pore walls in the entry areas of pores will be extended longitudinally. In the process of increasing the polishing depth, the number of main phase transformation atoms increased, and the degree of phase transformation in the pore area deepened.