Studies of defects and annealing behavior of silicon irradiated with 70MeV 56Fe ions

Abstract: The effects of 70MeV irradiation of iron ions in p-type silicon at fluences between 1×1012 and 5×1014 ionscm−2 were investigated by high resolution X-ray diffraction (HRXRD), electron spin resonance (ESR) and current–voltage measurements. The irradiated samples were isochronally annealed in nitrogen ambient up to 973K for 2min using the rapid thermal annealing (RTA) system. The screw dislocation density of the annealed sample (5×1014 ionscm−2) estimated at each stage of annealing from the broadening of the HRXRD peak was observed to change from 8.70×107 to 1.58×107 cm−2 with increasing temperatures. The strain and stress parameters estimated at each stage of annealing using the FWHM of ω-scan clearly indicate relative trend towards the un-irradiated silicon sample. The electron spin resonance studies indicate the presence of the dangling bond state of silicon (Siomplex defects. The annealing at 873K was found to be sufficient for complete removal of the defect centers induced due to irradiation. The I–V studies performed on the irradiated samples before and after annealing indicate that the defects created as a consequence of irradiation trap the charge carriers. [Copyright &y& Elsevier]