Surface characteristics and material removal mechanisms during nanogrinding on C-face and Si-face of 4H-SiC crystals: Experimental and molecular dynamics insights

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4H-SiC wafers hold significant promise for applications in power devices and radiofrequency devices. In order to develop a cost-effective and efficient grinding technology for 4H-SiC wafers, it is imperative to thoroughly investigate the mechanisms underlying damage evolution on different crystal faces of 4H-SiC. Our approach involved employing a range of experimental techniques including nanoindentation, scratching, and grinding, coupled with molecular dynamics (MD) simulation to systematically analyze the material removal mechanisms on both the C-face and Si-face. Through a comprehensive comparison of mechanical properties, surface morphology, and subsurface damage distribution between the C-face and Si-face, we uncovered the plastic deformation mechanisms operating on each face. Our research findings emphasize that, compared to the Si-face, the C-face exhibits higher elastic modulus and hardness, but lower fracture toughness. Additionally, due to the C-face’s greater propensity for high-density dislocation formation compared to the Si-plane, stress release occurs in the machining area, resulting in smaller normal forces and aiding in reducing surface roughness after grinding. This study provides important guidance for the grinding of the two critical basal planes of single-crystal 4H-SiC.