Dislocation formation and B transient diffusion in C coimplanted Si

Suppression of dislocation formation and boron transient diffusion by carbon coimplantation is studied by means of transmission electron microscopy, secondary-ion-mass spectrometry, photoluminescence spectroscopy, and high-resolution x-ray diffraction. It is shown that both the effects are due to the formation of C-related damage which acts as a trap for Si interstitials. Quantitative simulations indicate that this damage is probably formed by coprecipitation of Si and C atoms in Si_1.15C complexes. These complexes also deteriorate the electrical properties of the implanted layer. They dissolve at annealing temperatures higher than 900 °C. When this occurs, the effect of C is reduced and both B transient diffusion and dislocations, as well as the recovery of the electrical properties, are observed.