Laser annealing studies on ion implanted iron in silicon

The annealing effect of laser pulses from ruby and neodymium glass lasers on ion implanted 57Fe in silicon is investigated by Moessbauer conversion electron spectroscopy. For light pulses (approximately 70 ns DURATION TIME) from a ruby laser with a power density of 1.5 J/cm2, the Moessbauer spectrum changes drastically upon irradiation. After the irradiation, a quadrupole doublet is observed. This is interpreted to be due to the precipitation of FeSi compounds of approximately FeSi2 composition. From anodic stripping of surface layers it is found that these precipitates are formed in a shallow surface layer of approximately 10 J/cm2. For lower power densities the Moessbauer spectra change only slightly but the implant with an average depth of approximately 650 A is found to move towards the surface to an average depth of approximately 300 A. (author)