Simulations of arsenic and boron co-implanted in silicon during RTA for ultra-shallow junctions realizations

We have used the simulator of TITAN process. The latter uses the finished elements method for the equations resolution of codiffusion. We have simulated arsenic (1016 atoms cm−2, 100 keV) and boron (2 × 1015 atoms cm−2, 30 keV) codiffusion profiles in the monosilicon, after rapid thermal annealing (RTA) by using the parameters by defect of simulator. We have noted the difference between the experimental distribution profiles measured with secondary ion mass spectrometry (SIMS) and those simulated. This lead us to readjust the profiles, changing the dopant diffusion coefficient in order to obtain the simulated profiles corresponding in a better way to the experimental profiles. The arsenic diffusivity values vary from 2 × 10−13 to 2 × 10−12 cm2/s in the amorphised zone; and from 4 × 10−16 to 6 × 10−14 cm2/s in the crystalline zone. As far as boron is concerned, they are from 10−15 to 6 × 10−14 cm2/s and from 10−14 to 4 × 10−13 cm2/s in the two zones cited, respectively.