A Comparison of Different Techniques for the Rapid Thermal Annealing of Ion Implants in Silicon

Abstract

ABSTRACTIn this paper, a comparative study is presented of different techniques used for the annealing of arsenic ion implants in silicon. The used techniques are: lamp annealing using a bank of tungsten-halogen lamps, CW laser annealing and conventional furnace annealing. The annealing quality of the implanted layers is evaluated in terms of dopant activation, dopant diffusion and final extended defect states. The furnace annealing combines a good electrical dopant activation with nearly complete annihilation of the a/c dislocation loops, but substantial diffusion of the dopant profile is measured. Laser annealing gives good electrical activation with very low diffusion, but fails in removing end-of-range extended defects. Furthermore, latent electrical active defects of a donor-type are created. The tungsten halogen lamp annealing gives comparable activation and the diffusion is still lower than can be resolved by SIMS measurements, while growth and annihilation of the a/c dislocation loops is present but not yet completed. These experiments are in agreement with theoretical comparison of the different annealing techniques based on the effective (T,t) coordinates of each technique, which favours RTA processes in the high temperature - “seconds” -time range.