The atomic-scale diffusion mechanism was investigated using molecular dynamics simulation. A substitutional boron atom diffused to the self-interstitial site when there existed a self-interstitial carbon atom in its nearest tetrahedral center and the system temperature was high. The bond between the boron and self-interstitial carbon atoms was never broken during the diffusion process; indicating that Bs-Ci pairs diffused in the lattice via the interstitial mechanism. The results suggested that boron diffusion was mediated by carbon self-interstitial and not by a vacancy mechanism. The activation energy and pre-factor for boron diffusion in diamond were estimated to be 0.23eV and 1.123 x 10-6cm2/s.

Molecular Dynamics Simulation on Boron Diffusion in Diamond. Hu, X.J., Dai, Y.B., Shen, H.S., He, X.C.: Solid State Communications, 2004, 132[8], 557-60