Monte Carlo Simulation of Gold Drop Formation and Movement over a Silicon Substrate

The simulation of Au droplet formation and motion along the Si(111) surface was carried out using a kinetic lattice Monte Carlo model. It was shown that the Si substrate orientation affects the shape of the etching pits created under golden drops. The absence of droplet directed motion on singular surfaces was demonstrated. A necessary condition for the directional droplet motion is the asymmetry of lateral facets at a liquid-crystal interface. The reason for this asymmetry may be the presence of steps on the vicinal surfaces. The influence of the surface misorientation angle and the substrate annealing temperature on the surface morphology and the characteristics of gold drops movement was analyzed. It was shown that gold deposition on the vicinal silicon surface at high temperature leads to step faceting. Monte Carlo simulations confirmed that the reason for the Au droplet movement during the gold deposition is the silicon substrate dissolution in the Au-Si melt in the tendency to reach the equilibrium silicon concentration in the melt.