James L. Blue, ACMD
Mark D. Stiles, Electron and Optical Physics Division, Physics Laboratory
Andrew Zangwell, School of Physics, Georgia Institute of Technology
Epitaxial growth, in which atoms are deposited on a substrate and continue the same crystal structure as the substrate, are widely used. Examples are Molecular Beam Epitaxial Growth and Chemical Vapor Deposition. Understanding the physics of epitaxial growth is important for optimization of the growth process.
We are modeling epitaxial growth by a Monte Carlo simulation; atoms impinge on a crystalline substrate, are adsorbed, and then hop around on the surface. It is a challenge to include realistic physics in the model and yet have the simulation run in reasonable time. Most simulations in the literature accept very approximate physics in order to run fast. Their simulations can give only qualitative results. We are including realistic physics; being right is better than being fast.
Blue has developed data structures and programs that allow simulations of epitaxial growth on various crystalline substrates at various orientations, such as bcc(100) and fcc(110). All the crystal details are isolated in special data structures, and a preprocessing program produces computer code specific to the substrate.
We will be using these programs to study growth of two-component alloys, in which the arrangement of the A-atoms and the B-atoms within the crystal structure depends on the binding energies of the atoms.