Studying the Au/Si(100) system using the modified embedded atom method

Abstract

Molecular dynamics simulations based on the modified embedded atom method were applied to study the formation of thin Au films on the Si(100) substrate. Different Au coverages were used to study how the Au concentration affected the structure and morphology of the thin Au film on the Si substrate. It was found that Au atoms re-evaporated from the Si surface below 1 ML coverage at room temperature, and became more stable when the coverage was increased. Above 1 ML, all the Au atoms stayed on the Si substrate without re-evaporation. In our simulations, no Au/Si intermixing was observed within the simulation time of 41.25 ps below 3 ML Au coverage at room temperature. We also calculated the surface stress as the system evolved with time. The calculations showed the surface stress oscillated intensively at the beginning of the simulations and became stable when the system approached equilibrium. Comparing the surface stress of the system at different Au coverages, we found that the surface stress became smaller when the Au coverage was increased. Lastly, we studied the influence of temperature on the Au/Si interactions. Our results showed Au and Si intermixed above 2 ML Au coverage at 800 K, indicating that the Au/Si interactions could be enhanced by increasing the temperature.