Molecular dynamics simulation of ultrasonic vibration-assisted nanocutting of monocrystalline silicon

Abstract

As the core substrate material for the semiconductor industry, monocrystalline silicon has long posed a major challenge for precision manufacturing in terms of high-precision and low-damage machining. Ultrasonic vibration-assisted machining technology has been proven to effectively improve the machining quality of hard and brittle materials, yet its atomic-scale mechanism remains incompletely understood. In this paper, molecular dynamics simulation is adopted to construct a three-dimensional model for ultrasonic vibration-assisted nanocutting of monocrystalline silicon with diamond tools. The effects of vibration frequency and amplitude on material removal behavior, cutting force, cutting temperature, atomic phase transformation and subsurface damage are systematically investigated. In terms of material removal, the number of chip atoms exhibits a non-monotonic variation that first decreases and then increases with the rise of frequency and amplitude. In terms of cutting force, the average tangential force continuously decreases while the normal impact load increases monotonically with the increase of vibration frequency and amplitude. In terms of cutting temperature, the average temperature in the cutting zone rises monotonically with increasing frequency and amplitude, and the amplitude exerts a more pronounced enhancement effect on temperature rise. In terms of atomic phase transformation, high frequency and large amplitude intensify the high-pressure phase transformation of monocrystalline silicon from the diamond cubic phase to bct-5, β-Sn and amorphous phases. In terms of subsurface damage, the thickness of the damage layer increases significantly with rising amplitude, while it is less sensitive to frequency modulation. Vibration amplitude serves as the dominant parameter determining the depth of subsurface damage, and the amplitude along the Z direction should not be excessively large. This study reveals the machining mechanism of ultrasonic vibration-assisted nanocutting of monocrystalline silicon at the atomic scale, providing microscale theoretical support for low-damage machining processes.