Investigation of the recovery behavior of irradiation defects induced by a neutron in 4H-SiC combining Raman scattering and lattice parameters

Nitrogen-doped 4H-SiC single crystals were neutron-irradiated at temperatures below 100 °C with a fluence of 2.67 × 1024n/m2. The specimens were annealed isochronally from 600 to 1700 °C to evaluate the crystalline defects induced by neutron irradiation and analyze their recovery behaviors. The lattice parameters and Raman spectra were recorded. The first-order model was used to analyze the lattice parameter recovery curves, yielding the rate coefficient, and activation energies at each annealing step. Raman spectroscopy confirmed that neutron irradiation caused the formation of several new C–C homonuclear and Si–C heteronuclear bonds in the 4H-SiC network. During annealing, the evolution of Raman scattering and the recovery of lattice parameters were asynchronous. At 1500 °C, the lattice parameter recovery reaches saturation. Raman spectra, on the other hand, continue to evolve with annealing until 1700 °C. The defect recovery mechanism was discussed using activation energies and the evolution of Raman spectra.Graphical abstractThe manuscript presents an investigation of the annealing behavior of neutron irradiated 4H-SiC. The irradiated defects recombination process is evaluated by X-ray diffractometry (XRD) and Raman scattering. X-ray single-crystal diffraction was employed to determine the lattice parameters and swelling. The quality and structure disorder of silicon carbide crystals irradiated and annealed at different temperatures were characterized by Raman spectroscopy. The relationship between Raman spectra changes and lattice recovery behavior, as well as the defect types and polytype transformation caused by irradiation were discussed. On this basis, the recovery path of irradiation defects during high temperature annealing is constructed.