Time Dependence of Phosphorus Diffusion and Dose Loss during Postimplantation Annealing at Low Temperatures

Transient enhanced diffusion (TED) of implanted phosphorus was extensively investigated under various ion implantation and annealing conditions. The effective diffusivities of each annealing time period were determined to study the evolution of TED under low-temperature annealing. It was found that TED decays at the early stage of low-temperature annealing until diffusion enhancement reaches a steady state. Further annealing causes a significant decrease of diffusivity as TED is completed. It was also found that higher implantation energy enhances diffusion because of slower decay of TED. However, higher implantation dose introduces more diffusion enhancement without changing the decay behavior of TED. Severe dose loss was observed during the TED period. It was found that the dose loss is controlled by TED. As a result, higher annealing temperature and longer annealing time lead to greater phosphorus dose loss.