Investigation of the elastic-plastic evolution mechanism of 4H-SiC substrates with external thermal-assisted abrasion

Abstract

Plastic removal is easier to achieve nanometric surfaces of monocrystalline SiC with brittleness in nano-polishing. This paper mainly focuses on the nano-scale elastic-plastic evolution mechanism of 4H-SiC substrates in thermal-assisted polishing using molecular dynamics simulation. The results show that 4H-SiC substrates undergo elastic deformation, elastic-plastic deformation, and plastic deformation in ramp nano-abrasion. The critical depth from elastic to elastic-plastic deformation rises with higher external temperature, and elastic-plastic deformation stage is compressed. Amorphization dominates the elastic recovery in elastic-plastic deformation stage. Furthermore, the step-terrace structure appears in elastic deformation stage, and is observed at a greater depth rising from 0.679 nm to 1.226 nm with increasing external temperature from 298 K to 700 K. High surface quality and subsurface damage-free of SiC substrates are performed with forming the atomic step-terrace structure.