MBE成長条件下での表面構造の周期変化とRHEED振動

抄録

The periodic change of the structure and the flatness of a growing surface under MBE conditions are theoretically investigated. The growth of the (001) face of the simple cubic lattice is simulated by using Gilmer and Bennema's model for vapor growth. We discuss the properties of the RHEED oscillation by combining this simulation and a kinematical formula for RHEED intensity. In MBE growth, lifetime τ, of an adatom before evaporation is much larger than the life time τ, of an adatom before capture by another adatom. If J is the incident beam flux and D_5, is the surface diffusion coefficient of adatoms, τ_c = (JD_5)^<-1/2>. The results of the Monte Carlo simulation and RHEED intensities calculated for the simulated growth are interpreted in term of lifetime τ_c and the mean diffusion length λ_c inτ_c. We obtain a diagram predicting the growth conditions under which the periodic change of a growing surface causing RHEED oscillation occurs, and the conditions for oscillations of RHEED intensity for stepped surfaces.