Interaction between point defects and dislocation loops as the phenomenon able to reduce anomalous diffusion of phosphorus implanted in silicon

Abstract

Phosphorus was implanted at doses below amorphization threshold in virgin silicon and in silicon containing interstitial dislocation loops. The loops were formed by high-dose Si+ implantation and 900 °C, 30 min annealing. Triple-crystal x-ray diffraction and junction depth measurements combined with secondary ion mass spectrometry were used for the analysis of implant defects and the determination of P distribution, respectively. Annealings were carried out in furnace in the range between 600 and 900 °C, and by electron beam at 1000 °C for 10 s. The results obtained show that the presence of loops strongly reduces the phosphorus anomalous diffusion. This phenomenon is the consequence of the absorption by the loops of the interstitial excess coming from dissolution of the clusters produced by the P implant. The influence of the loop position with respect to the P distribution on the extent of P diffusivity is analyzed and discussed.