Indium out-diffusion from silicon during rapid thermal annealing

The out-diffusion of indium (In) from In-implanted silicon (Si) samples that includes bare Si, samples with an oxidecap layer, nitride-cap layer, and nitride/oxide/Si sandwiched samples, is investigated. The dose loss of In with respect to different implant energies, doses, and soak times during rapid thermal annealing (RTA) is quantified. Experimental results of bare Si samples show that over 90% of In out-diffusion happens within 1 sec of soak time in the RTA process. In the capped samples, In rapidly diffuses through the oxide layer and stops at the nitride/oxide interface. In gets piled up at the interface of Si/oxide and oxide/nitride, and nitride very efficiently prevents In out-diffusion from the oxide layer out to the nitride layer. In addition, In gets more segregated in the Si surface in the presence of boron.