Investigation of Removal Mechanism of 4H-SiC and 6H-SiC Substrates Using Molecular Dynamics Simulation Zige Tian 1,2 , Xun Chen 2 and Xipeng Xu 1 1 Institute of Manufacturing Engineering, Huaqiao University, Xiamen, 361021, Fujian Province, P.R. China 2 Faculty of Engineering and Technology, Liverpool John Moores University, L3 3AF, Liverpool, United Kingdom X.Chen@ljmu.ac.uk Abstract. Single crystal silicon carbide (SiC) is widely used in semiconductor devices and illumination devices. The anisotropic characteristics of SiC crystal structure presents different physical properties on the C face and Si face of a single crystal silicon carbide leading to different applications. Aiming at the understanding of the mechanism of material removal and subsurface defect, this paper presents the molecular dynamics simulations of scratching on the C face and Si face of 4H-SiC and 6H-SiC materials. The results show that the material removal at the C face is easier than that at the Si face, so that less subsurface amorphous deformation appears on the C face. Such a difference is due to a key phenomenon - the dislocations on the basal plane (0001) in the SiC subsurface during scratching. 1. Introduction Single crystal silicon carbide (SiC) plays very important roles in many engineering applications because of some excellent properties, such as high thermal conductivity and stability, high stiffness and good chemical inertness [1]. Within different polytypes of SiC, 4H-SiC have wide applications for optoelectronics, high-temperature electronics, high-performance mirrors and micro/nano dies; while 6H-SiC is mainly used for optoelectronic devices, such as diodes for laser and blue light emitting [2-5]. These ultra-precision micro/nano components require damage-free atomically smooth surfaces, because any nanoscale defects either derived from the material growth or produced from the machining process are harmful to SiC-based devices [6]. Thus, the investigation of the nanoscale mechanical properties and material removal mechanism of 4H-SiC and 6H-SiC substrates is of great interests and significance, therefore it has attracted a lot of attention in research community. Scholars have undertaken indentation and scratching experiments, which are common methods to study the nanomechanical properties of on 4H-SiC and 6H-SiC. Indentation load-displacement curves could show the material deformation transition conditions between elastic, plastic and fracture. Researches [7, 8] demonstrated the yielding or incipient plasticity of 4H-SiC and 6H-SiC at a pop-in event are of a shear stress of about 21 GPa and 23.4 GPa. Grim et al. [9] experimentally confirmed that basal dislocation could appear in the subsurface of 6H-SiC during mechanical polishing. It is difficult to observe nanoscale phenomena experimentally, while molecular dynamics (MD) can be applied effectively to illustrate the movement and interaction of molecules or atoms and to allow the material deformation and removal mechanism during indentation and scratching on 4H-SiC and brought to you by CORE View metadata, citation and similar papers at core.ac.uk provided by LJMU Research Online