Revealing the Nanoindentation-Induced Plastic Deformation Mechanisms of 4H-SiC: Combined Insights from Molecular Dynamics Simulations and Experiments

4H-SiC substrate is widely employed in semiconductor device fabrication owing to its unique crystal structure and excellent physicochemical properties. However, its deformation behavior during substrate processing remains complex and not fully understood. In this study, molecular dynamics (MD) simulations were performed to systematically investigate the deformation mechanism of single-crystal 4H-SiC during nanoindentation, serving as an atomic-scale analogue of the workpiece–abrasive interaction during substrate processing. Specifically, the relationship between the fluctuations of the load–depth curve and slip were revealed, with particular emphasis on the basal slip (BS) and prismatic slip (PS) behaviors. The results indicate that the fluctuations in the load–depth curve are primarily associated with the nucleation and propagation of dislocations. The initiation of BS is predominantly influenced by the atomic arrangement and stress distribution, while PS initiates at the terminus of BS as the indentation depth increases. Finally, nanoindentation experiments were conducted to validate the reliability of the MD simulations. These findings provide valuable insights into the deformation mechanism and mechanical behavior of 4H-SiC during practical substrate processing.