Special features of spatial redistribution of selenium atoms implanted in silicon

The spatial distribution of selenium atoms implanted in silicon was studied by secondary-ion mass spectrometry after annealing in the temperature range of 600-1200 deg. C. For implantation doses exceeding the amorphization dose for silicon, formation of a peak of selenium concentration was detected beyond the mean projected range of selenium ions. The spatial position of the peak correlates well with the spatial position of the plane in which the calculated value of the specific energy losses of selenium ions in elastic collisions (according to the TRIM code) corresponds to the critical value for amorphization of silicon. Accumulation of impurities at the peak occurs at temperatures of 700 deg. C and higher after recrystallization of the amorphized layer. Redistribution of selenium atoms to deeper layers of the sample due to diffusion is controlled by the temperature dependence of the solubility of selenium in silicon