Isothermal annealing of selenium (Se)-implanted silicon carbide: Structural evolution and migration behavior of implanted Se

Isothermal annealing studies of selenium-implanted silicon carbide (SiC) were conducted at temperatures >1200 degrees C. Implantation were performed using Se ions of 200 keV to a fluence of 1 x 1016 cm- 2at room temperature, 350 degrees C and 600 degrees C. After implantations, samples were then subjected to an isothermal annealing process at 1300 degrees C, 1350 degrees C and 1400 degrees C for 10 h cycles up to 80 h. The radiation damage in SiC and its morphological change were characterized using Raman spectroscopy and scanning electron microscopy (SEM), respectively. The migration of implanted Se was monitored by Rutherford backscattering spectrometry (RBS). Implantation at RT amorphized SiC while implantation at 350 and 600 degrees C retained crystallinity with defects. Isothermal annealing led to significant recrystallization during the first annealing cycle in all annealing temperatures. The broadening of the Se RBS profile was observed in the RT implanted samples only during the first and second annealing cycles at all annealing temperatures. The diffusion coefficients at 1300 degrees C, 1350 degrees C and 1400 degrees C were estimated to be 1.4 x 10-20 m2s- 1, 2 x 10-20 m2s- 1 and 2.5 x 10-20 m2s- 1, respectively, which yielded to an activation and pre-exponential factor of 2 x 10-22 J and 1.7 x 10-16 m2s- 1 respectively. No measurable diffusion of the Se implanted into SiC was observed in the isothermally annealed hot implanted samples (at implantation temperature of 350 degrees C and 600 degrees C) confirming the radiation enhanced migration of Se in the RT implanted samples.