It was well known that substitutional carbon atoms could capture excess self-interstitial silicon atoms and suppress the diffusion of ion-implanted interstitial-type dopants, such as boron , in Si. In the case of B concentrations as high as ∼1021/cm3, the B activation ratio in Si decreased with C incorporation. Thus, many studies on stable B-containing clusters and/or precipitates in heavily doped Si with a C additive had thus far been conducted. However, the impact of the C incorporation on the activation and clustering of B atoms in Si was yet to be researched. Here, the chemical bonding features of B and C atoms in heavily B-doped Si with different C contents after high-temperature annealing were characterized systematically by high-resolution X-ray photo-electron spectroscopy. It was found that the C incorporation enhances B-clustering at B concentrations higher than ∼1021/cm3 after 1050C spike annealing. In addition, the formation of C–B bonds with accompanying B-clustering was confirmed by photoemission measurement using a hard X-ray. As a result, the intrinsic B-diffusion was observed to be markedly suppressed by the C incorporation under thermodynamic equilibrium annealing at 1000C.

Contribution of Carbon to Growth of Boron-Containing Cluster in Heavily Boron-Doped Silicon. H.Itokawa, A.Ohta, M.Ikeda, I.Mizushima, S.Miyazaki: Japanese Journal of Applied Physics, 2010, 49[8], 081301