Energetics of Ti atom diffusion into diamond film

Energetics of Ti atom in metallization of diamond film were studied by calculations using density functional theory (DFT) and a composite basis set. Cluster models consisting of more than 10 C atoms were chosen to simulate the diamond phase with their boundaries saturated with H atoms. When Ti atom diffuses from the surface into the bulk of diamond interstitially, the energy barriers were found to be about 40 eV. Ti was found to favor substitutional sites rather than interstitial sites in diamond crystal. Our results indicate that the high concentration of Ti in chemical vapor deposited diamond films after metallization would occupy the grain boundaries rather than the bulk of diamond grain.