Effect of anisotropy on deformation and crack formation under the brittle removal of 6H-SiC during SPDT process

Introduction: Monocrystal SiC is representative of the third generation semiconductor materials, the efficient process technology of 6H-SiC wafer have always been a hot topic. Developing a SPDT processing method based on brittle removal mode with controllable surface/subsurface damage is an important approach to solve the processing difficulties of 6H-SiC. Objectives: This work aims to analyze the brittle removal process and fully explain the brittle separation behavior and deformation mechanism of 6H-SiC. The micro -scale crack propagation and the effect of anisotropy on crack distribution during machining process are investigated. Methods: Large-scale molecular dynamics simulation was used in this work. Results: Under the condition of brittle removal, shear fracture occurs in the front area of tool tip. Shear plane is high -index surface, independent of slip system. The location of tensile fracture is the cleavage plane of hexagonal system, and the fracture surface is composed of step -like joint planes or perfect plane structures. Cracks with self -healing capability appear in the area behind the tool when the surface to be machined is basal plane. When the surface to be machined is not basal plane, a large number of dislocations or cracks remain in subsurface region. Under brittle removal mode, a large amount of plastic deformation appears as well, and deformation mode is related to processing scheme. Conclusion: The brittle removal behavior of 6H-SiC under SPDT process has obvious anisotropy. Basal plane is more suitable for brittle removal of 6H-SiC without residual damage such as sub -surface cracks. The crack behind the tool generated by cleavage fracture can be repaired by itself. Fracture behavior is not related to dislocation. The processing method parallel to the c -axis can cause the generation of a large number of surface cracks. The (011 0)/[2 1 1 0] and (112 0)/[11 00] mode is the best way to achieve plastic removal of 6H-SiC during SPDT process. (c) 2024 The Authors. Published by Elsevier B.V. on behalf of Cairo University. This is an open access article under the CC BY -NC -ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).