Beyond TED: understanding boron shallow junction formation

As implant energies are reduced with the aim of forming shallower junctions, transient enhanced diffusion (TED) effects are greatly reduced. With TED less pronounced, other effects emerge to dominate the diffusion of dopants such as boron. In particular, coupled dopant/defect diffusion injects interstitials leading to enhanced tail diffusion, while oxidation and the diffusion of silicon through thin oxides affects the surface point defect concentrations. This paper shows that by careful consideration of models developed for much deeper junctions, the dependence of junction depth on processing conditions can be understood for shallow junctions as well.