Anomalous diffusion of lightly implanted As into a Si substrate was observed during furnace annealing in a N ambient. The anomalous behavior was reflected by the appearance of clear features in the near-surface and tail regions. In the near-surface region, which extended to between 30 and 50nm from the interface, a large number of As atoms moved towards the oxide/Si interface and occasionally accumulated in a narrow region which was between 10 and 20nm from the interface. Retarded diffusion was observed in the tail region. The diffusivity in the tail region increased with increasing annealing time.

N.Aoki, T.Kanemura, I.Mizushima: Applied Physics Letters, 1994, 64[23], 3133-5