Low temperature carbon co-implantation in silicon: Defects suppression and diffusion modeling

Carbon has been co-implanted to phosphorus at low temperature (−100 °C) in silicon. As compared to a room temperature carbon implant, phosphorus activation is increased due to the suppression of extended defects. The unusual carbon depleted region observed in both secondary ion mass spectroscopy and atom probe tomography annealed profiles has been explained and modeled using an interstitialcy diffusion barrier of 0.6 eV. Carbon clusters have been interpreted as being composed of several immobile dimers carbon/self-interstitial, in agreement with the stoichiometry of the SiC phase. From the model presented here, an adequate temperature window (>750 °C) has been found regarding self-interstitials trapping by carbon.