Applications of molecular dynamics to irradiation effects in materials

APPLICATIONS OF MOLECULAR DYNAMICS TO IRRADIATION EFFECTS IN MATERIALS 

With a view to presenting the state of the art and the capabilities of MD of atomic collisions in solids, we shall briefly discuss some examples. The emphasis wiU be on theoretical aspects of the simulations, rather that on their relation to experimental results. 

Semiconductor technology shallow boron dopant on silicon 

The process of semiconductor doping consists normally of two steps implantation of the dopant and annealing, to eliminate those defects created 

Low-energy boron bombardment of silicon has been simulated at room temperature by MD. Tersoff potential T3 was used in the simulation and smoothly linked up with the universal potential. The boron-silicon interaction was simulated according to Tersoff potential for SiC but modified to account for the B-Si interaction. Silicon crystal (Si-c) in the (001) direction, with (2x1) surface reconstruction, was bombarded with boron at 200 and 500 eV. Reasonably good statistics are obtained with 1000 impact points uniformly distributed over a representative surface area. The simulation size was 16x 16x 14 unit cells. Periodic boundary conditions were applied laterally. The temperature was kept at 300 K with a thermal bath applied to the more external cells in the crystal except the top surface. In these conditions the crystal was relaxed during 19 ps. In order to avoid direct channeling, the incidence was inclined 7° out of the normal, as usual in experiments, with random azimuthal direction. 

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Applications of molecular dynamics to irradiation effects in materials... 

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