Probing the surface/subsurface damage mechanism of laser assisted single-grain scratching of 4H-SiC based on molecular dynamics

Abstract

SiC exhibits tremendous potential for semiconductors and microelectronics applications due to its excellent attributes. 4H-SiC is a difficult-to-machine material owing to its unique anisotropy, high hardness, and high brittleness. 4H-SiC is generally processed by grinding, but the material removal efficiency is low, and there are machining defects on the surface. Laser assisted grinding can enhance both the efficiency of processing and the quality of surfaces. However, the mechanism of material removal and damage by laser action on 4H-SiC remains ambiguous, so this paper utilizes the method of molecular dynamics to explore the surface/subsurface damage mechanism of laser assisted single-grain scratching of 4H-SiC crystals and systematically investigates the effects of laser power on the material damage, scratch force, stress, chip morphology, dislocations, and subsurface damage to probe the material removal mechanism of the scratching process. The results demonstrate that as the laser’s intensity rises, the scratching force and stress decrease, and the depth of subsurface damage diminishes. Transformations of 4H-SiC into the more stable 3C-SiC crystal form were found near the incomplete dislocation lines at high power densities. This study reveals the intrinsic mechanism of laser assisted grinding processing of 4H-SiC and provides theoretical guidance for laser assisted grinding processing.