Effect of Lattice Mismatch on the Decay of Rheed Oscillations During Growth of Strained InGaAs/GaAs Heterostructures

Abstract

ABSTRACTThe decay of the oscillation of the intensity of the specular beam of the reflection high-energy electron diffraction pattern is analyzed during the molecular beam epitaxial growth of strained InGaAs/GaAs heteroepitaxial structures. The oscillations' amplitude was found to decrease exponentially versustime during the InGaAs growth. Further, the decay time constant decreases with InAs mole fraction, indicating that the lattice strain increases islanding during growth. A simple semi-quantitative model based on the growth front roughening is formulated to explain the results. Assuming that the oscillation decay is related partly to the strain and partly due to kinetic effects during growth, a decay component that is solely due to strain can be separated; we find that the onset of increased roughening due to misfit strain component roughly corresponds to the equilibrium critical layer thickness