Molecular-dynamics subplantation studies of carbon beneath the diamond (111) surface

The near-surface implantation of hyperthermal neutral carbon atoms of energy (15--75) eV onto a low-temperature diamond (111) substrate is studied by molecular dynamics using a density-functional-based nonorthogonal tight-binding scheme. Depending on the initial energy and the impact point, the atoms penetrate beneath the exposed (111) surface forming regions of local disorder and stress. The energy partition during the collision is analyzed, yielding results about penetration and the displacement threshold. After a final relaxation of the structures we determine the penetration depth of the colliding particles. The structural topology and the electronic properties of the induced defects and surface modifications are discussed.