Diffusion of phosphorus during rapid thermal annealing of ion-implanted silicon

The diffusion of ion-implanted phosphorus in silicon during rapid thermal annealing has been studied. Depending on the implant dose, we find two distinct kinds of diffusion behavior. For low dose (1×1014 cm-2) P+-implanted Si, a profile redistribution is observed which becomes observable at 900°C for annealing times of 10 s, but which is temperature independent in the range 800-1150°C. This initial redistribution is much more rapid than conventional diffusion coefficient data would predict. For high dose (2×1015 cm -2) P+ implanted and short time (10 s) annealed Si, the dopant profile broadening is strongly temperature dependent. The experimental profiles are in this case in agreement with concentration enhanced diffusion profiles.