Photo-induced iron atom motion of iron-acceptor pairs in silicon

Iron (Fe)-aluminium (Al) and iron-boron (B) pairs in silicon are shown to have excitation-induced dissociation due to light illumination at around 150 K where thermally activated motion of iron atom is almost impossible. Iron was doped by annealing of specimens pre-doped with Al or B in Fe vapor at 1050 degrees C followed by quenching. At first Fe-acceptor pairs were generated by annealing these specimens at 80 degrees C. Then illumination effect on the concentrations of the first and second neighbor pairs of Fe-acceptor was examined at various temperatures. Illumination of light at around 150 K reduced the concentration of the first neighbor pair meanwhile increased that of the second neighbor pair. The activation energy of Fe atom motion from the first to second neighbor of Al atom is 0.11 eV under light illumination which is much smaller than that (0.80 eV) of ordinal motion.