Physical insight into ultra-shallow junction formation through atomistic modeling

We use atomistic simulations to gain physical understanding of relevant dopant–defect interactions involved in junction formation. The analysis of the energetics of B–Si interstitial clusters (BICs) indicates that a high Si interstitial supersaturation is necessary to nucleate BICs in crystalline Si, but only a Si interstitial supersaturation slightly larger than that set by BICs is enough to cause the stabilization and growth of preexisting BICs. We have analyzed the mechanisms associated to B uphill diffusion and deactivation in preamorphized Si upon subsequent annealing. Both phenomena occur simultaneously and they are the result of the trapping of B atoms by preexisting B clusters in the high concentration region.