Insights into the effects of Al-ion implantation temperature on material properties of 4H-SiC

In this study, Al implantation in 4H-SiC at the dose of 1 x 1014 cm-2 was investigated. The impacts of im-plantation temperature on the lattice quality, microstructure, surface composition, and band structure were all studied experimentally and theoretically. Atomic force microscope (AFM) images showed the difference in surface morphology between high-temperature and low-temperature implantation. Transmission electron mi-croscopy (TEM) characterization indicated the lattice damage induced by implantation was recovered after the post-annealing at 1750 degrees C, except for the samples implanted at room temperature. X-ray photoelectron spec-troscopy (XPS) analysis suggested an oxidation effect during and after the implantation process, and it was more serious at lower implantation temperatures. As the implantation temperature incremented, the ratio of Si-C composition with high binding energy increased, the element valence became closer to that of ideal Al-doped 4H-SiC calculated by density functional theory (DFT); and the Fermi level shifted toward the valence band maximum (VBM), demonstrating the formation of efficient p-type doping. A more obvious asymmetric broad-ening in Raman spectroscopy was observed at higher implantation temperature. The theoretically obtained band structures and bond lengths from DFT calculations corroborated the experimental results, providing physical insights into the possible effect mechanism. In sum, correlations between the implantation process, external material properties, and internal crystal structure were recorded, paving the way for further research and future applications.

Automated summary

This study investigated the effects of Al implantation in 4H-SiC at a dose of 1 x 1014 cm-2. Both experimental and theoretical methods were used to study the impacts of implantation temperature on lattice quality, microstructure, surface composition, and band structure. The results revealed differences in surface morphology, lattice damage recovery after post-annealing, and oxidation effects during and after the implantation process. These findings provide insights into the effect mechanism and contribute to further research and applications.