Abstract
Single crystal silicon carbide (SiC) is widely used for optoelectronics applications. Due to the anisotropic characteristics of single crystal materials, the C face and Si face of single crystal SiC have different physical properties, which may fit for particular application purposes. This paper presents an investigation of the material removal and associated subsurface defects in a set of scratching tests on the C face and Si face of 4H-SiC and 6H-SiC materials using molecular dynamics simulations. The investigation reveals that the sample material deformation consists of plastic, amorphous transformations and dislocation slips that may be prone to brittle split. The results showed that the material removal at the C face is more effective with less amorphous deformation than that at the Si face. Such a phenomenon in scratching relates to the dislocations on the basal plane (0001) of the SiC crystal. Subsurface defects were reduced by applying scratching cut depths equal to integer multiples of a half molecular lattice thickness, which formed a foundation for selecting machining control parameters for the best surface quality.
Highlights
Single crystal silicon carbide (SiC) has extensive applications in microelectronics, optoelectronics, aerospace, and medical sectors because of its specific properties, such as chemical inertness, high thermal conductivity, high specific stiffness, and high-temperature stability [1]
This paper presents a study on the removal mechanism of 4H-SiC and 6H-SiC substrates during scratching using Molecular dynamics (MD) simulations in order to explain the differences in the machinability of the Si face and C face
The temperature of the thermostatic layer was controlled at 300 K during the simulation, and the relaxation process of the system was taken for 150 ps before the simulated scratching began
Summary
Single crystal silicon carbide (SiC) has extensive applications in microelectronics, optoelectronics, aerospace, and medical sectors because of its specific properties, such as chemical inertness, high thermal conductivity, high specific stiffness, and high-temperature stability [1]. Nano-indentation results of high-resolution transmission electron microscopy confirm two major material deformation mechanisms, including amorphous deformation generation near the indentation region and dislocation propagation along both the basal and prismatic planes [17]. Considering the anisotropy of SiC, different crystal planes and orientations significantly influence the deformation mechanism and removal efficiency of the material. Tian et al [28] compared the indentation of C and Si faces of 4H- and 6H-SiC through MD simulations and experiments They found that the C face is more prone to dislocation on the basal plane than the Si face. This paper presents a study on the removal mechanism of 4H-SiC and 6H-SiC substrates during scratching using MD simulations in order to explain the differences in the machinability of the Si face and C face.
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