Ultra low sheet resistance on poly silicon film by excimer laser activation

We found that the sheet resistance (Rs) value of phosphorus-doped poly-Si film activated by excimer laser annealing (ELA)' has a strong correlation with the crystallinity in the film. At the optimum ELA condition of 10 shots and 450 mJ/cm(2) we achieved avery low Rs value of 60 ohm/sq. in poly-Si films. With laser activation, we could get much lower Rs than with conventional rapid thermal annealing (RTA), for silicon layers of the same crystallinity level. The active dopant diffusion is observed from the energy which is speculated to correspond to the near-complete-melting energy regime during laser irradiation.