Correlation between island-formation kinetics, surface roughening, and RHEED oscillation damping during GaAs homoepitaxy

The basic mechanisms controlling surface roughening and its correlation to the damping behavior of reflection high energy electron diffraction (RHEED) intensity oscillations are studied. The experimental observations are compared to results of Monte Carlo simulations of atomistic processes on the growing surface, such as surface diffusion of both Ga atoms as well as of slowly migrating GaAs molecules. With the simulation model, quantitative reproduction of the temperature and III/V flux-ratio dependence of RHEED oscillation damping by simulated step density oscillations is demonstrated. Systematic simulation studies are performed to examine the relationship between oscillation decay, surface roughening, nucleation rate, surface kinetics, and the prevalent growth conditions. The nucleation rate is identified as the central quantity which determines both the oscillation damping as well as the surface roughening.