Molecular dynamics simulation of Si(001) surface: surface reconstruction, melting and epitaxial growth

We have studied the structure, melting transition and molecular beam epitaxy (MBE) of the Si (001) surface using the molecular dynamics simulation technique together with the Stillinger-Weber model potential. The structure of the simulated surface shows dimerized (2×1) symmetry and the surface contains spontaneous defects. The dimers are symmetric and neither buckled nor twisted. The surface induced melting is found to start below the bulk melting point. During the MBE growth, at high substrates temperature, 800 K, well ordered crystalline layers are found to grow underneath an amorphous overlayer of approximately 5 angstrom thick. A limiting temperature for epitaxial growth is found to be 480 K, below which the growth does not produce ordered layers.