An atomistic kinetic Monte Carlo model was presented for boron diffusion in amorphous silicon. The diffusion was assumed to be indirect, and mediated by the dangling bonds present in a-Si. The model had a transient character due to a-Si relaxation modeled by dangling-bond annihilation. In addition, the B produced clusters at higher concentrations, leading to an immobile B fraction. The model was successfully applied to experiments on the thermal annealing of amorphized B marker layers and B implantation into pre-amorphized Si. The contribution of B diffusion in a-Si to ultra-shallow junction formation was studied. The model was also used to demonstrate how the contribution to diffusion of B in a-Si in current and future technologies could be higher than in c-Si.

Indirect Boron Diffusion in Amorphous Silicon Modeled by Kinetic Monte Carlo. I.Martin-Bragado, N.Zographos: Solid-State Electronics, 2011, 55[1], 25-8