Helmut Tews

Nitrogen-induced transient enhanced diffusion of dopants

Studies of both systematic experiments and detailed simulations for examining the effects of N2+ implant on channel dopants are described. Step-by-step monitor wafer experiments have clearly confirmed the nitrogen-induced transient enhanced diffusion (TED) of dopants. Process simulations within the “+1” N2+ profile approach have demonstrated the need to scale down the +1 model parameter for matching the measured depth profiles. The underlying mechanism for the reduced +1 model parameter is that nitrogen which diffuses toward the Si surface becomes a sink for the interstitials. These combined studies also show that nitrogen-induced TED of dopants increases with N2+ dose.