Molecular dynamics simulation on boron diffusion in diamond

The atomic-scale diffusion mechanism of boron in diamond is investigated by molecular dynamics simulation. A substitutional boron atom diffuses to the self-interstitial site when there exists a self-interstitial carbon atom in its nearest tetrahedral center and the system temperature is high. More important, the bond between boron and the self-interstitial carbon atom is never broken during the diffusion process, indicating that Bs–Ci pairs diffuse in the lattice by the interstitial mechanism. The results suggest that boron diffusion is mediated by carbon self-interstitial and not by the vacancy mechanism. In addition, the estimated activation energy and the diffusion exponential prefactor of boron diffusion in diamond are found to be 0.23 eV and 1.123×10−6cm2/s, respectively.