Physically based kinetic Monte Carlo modeling of arsenic-interstitial interaction and arsenic uphill diffusion during ultrashallow junction formation

A kinetic arsenic-interstitial interaction model has been developed to study and predict arsenic transient enhanced diffusion (TED) and deactivation behavior during ultrashallow junction (USJ) formation. This model is based on density functional theory and has been verified by previous experiments in which the significant role of interstitial mechanism in arsenic TED was revealed. The mechanism of enhanced and retarded arsenic diffusion in different point defect environments is investigated by utilizing this model in kinetic Monte Carlo simulation. The arsenic-interstitial pair, with low binding energy and low migration energy, is shown to be the major contributor to arsenic TED in silicon interstitial-rich situations. In addition, by using this model, we demonstrate the transient existence of arsenic-interstitial clusters ( As n I m ) during postimplant annealing and propose their possible role in deactivation for short time annealings such as laser annealing and spike annealing. Moreover, we have developed a novel surface-trap based kinetic Monte Carlo model to simulate arsenic uphill diffusion in proximity of the Si ∕ Si O 2 interface. The simulation results show that the activation behavior of the uphill portion of arsenic has considerable impact on the junction sheet resistance. The activation behavior of this arsenic is expected to become more important when USJ depth is scaled down further.