Atom correlation and configurational ordering in pseudobinary epitaxial semiconductors

Epitaxial-growth dynamics of the binary alloy system has been modeled taking into account the interatomic interaction (atom correlation) in the surface adsorption and diffusion processes on the basis of the effective Ising Hamiltonian of binary elements. A stochastic differential equation describing the epitaxial-growth kinetics has been derived. The adsorption and the diffusion (atomic jump) probabilities are defined by considering the local configurational energies at the adsorption sites. This makes it possible to couple the effective Ising Hamiltonian with the stochastic differential equation. The Monte Carlo (MC) calculation based on the stochastic equation has successfully revealed the dynamic change of the atomic arrangement as a function of the surface coverage. The evolution processes of short-range ordering (SRO) and long-range ordering (LRO) during the epitaxial processes were also quantitatively evaluated as functions of surface coverage and substrate temperature. It has been revealed that the formations of SRO and LRO are governed by the interplay of adsorption and diffusion processes with the atom correlation effect.