Modification mechanism of collaborative ions implanted into 4H-SiC by atomic simulation and experiment

Ion implantation is increasingly applied to assist machining micro/nano devices in academic research and industry. A method of heavy ions assisted light ions implantation was proposed to modify 4H-SiC for reducing difficulty in ultra-precision machining. First, a three-dimensional molecular dynamics (MD) simulation model for ion implantation into SiC surface was established. The lattice damage mechanism of SiC under implantation of different ions including H⁺, Cu²⁺, and collaboration of Cu²⁺ and H⁺was studied. Projection range of the model with collaboration of Cu²⁺ and H⁺ was the largest. Then, the workpiece after ion implantation was annealed to study residual stress. The results show that high-temperature annealing contributes to reducing residual tensile stress. Finally, a MD model with length of 1530 Å along the Z-axis was built to compare with actual experiments using the same ion implantation parameters. The resulted subsurface damage values were quite close which demonstrates feasibility of the MD model. Surface morphology, cross-section of the defects, and three-dimensional ion distribution on the implanted samples surface were also observed and displayed. As demonstrated by simulation and experiments, the method of collaborative ion implantation can effectively modify surface of hard and brittle materials and bring benefits for subsequent ultra-precision machining.