Investigations on ion irradiation induced strain and structural modifications in 3C–SiC.

Ion irradiation induced recovery of defects in 3C–SiC caused by electronic energy loss (S e) in the intermediate energy regime (a few 100s of keV to a few 10s of MeV) is less explored. Towards this, separate and sequential ion irradiation of 200 keV Si+ ions and 14 MeV Si+ ions in 3C–SiC were carried out. In our earlier work, RBS/C findings demonstrated that 14 MeV Si+ ion irradiation (S e - 4.9 keV/nm) resulted in defect recovery in 3C–SiC pre-damaged with 200 keV Si+ ions [1]. The present work investigates the strain and structural evolution using High-resolution X-ray diffraction (HRXRD), Reciprocal space mapping (RSM), X-ray absorption near edge spectroscopy (XANES) and Diffuse reflectance spectroscopy (DRS), in the 3C–SiC layer as a result of ion irradiation induced defect production and recovery. HRXRD results revealed that 200 keV Si+ ion results in 4 % of strain at the projected range of ions and strain relaxation as a result of ionization-induced annealing is observed after subsequent 14 MeV Si+ ion irradiation. RSM measurements showed evidence for the formation of extended defects in sequentially ion irradiated samples. Optical characterization using DRS measurements indicates a reduction of refractive index in the ion-irradiated layer, however, for the amorphous SiC layer (ion dose: 0.6 dpa, 200 keV Si+ ion), the refractive index increased due to a reduction in mass density. Modification of refractive index in the ion irradiated layer is a result of the combination of negative change in volume effect and positive change in electronic polarizability. [Display omitted] [ABSTRACT FROM AUTHOR]